Arthroscopic treatment of scaphoid nonunion, a new algorithm after six years practice

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Till now most of the patients have been treated with open revision, bone grafting and internal stabilization. Arthroscopy plays an increasing role in hand surgery since the last decade. Three years after starting the use of arthroscopic treatment of scaphoid nonunion we analyzed our results and modified our therapy protocol. Material and Methods: In 2017, we started arthroscopic treatment of scaphoid nonunion at our department. Debridement is done arthroscopically as well as insertion of radius cancellous bone graft. Fixation has been accomplished with K-wires and/or head compression screws percutaneously, by help of x-ray. Till 2020, we treated 24 patients, observing three delayed unions, treated successfully by extra corporal shockwave therapy and modifying the fixation. Analyzing these results, we modified our fixation methods and all patients, got shockwave therapy additionally. Results : Comparing the success rate with the 28 operated after 2020, the adaption of our algorithm showed an improvement of our results concerning healing rate. There we found only one ongoing nonunion in the proximal 1/3. The median time to healing was comparable in the two groups, operation time showed no significant difference. After a median follow-up of 30 months, we found an excellent range of motion, a significant reduction in pain and grip strength matchable with the unaffected hand in all 52 patients. DASH and Mayo Wrist Score showed satisfactory results, and 45 patients came back to their earlier occupation and sports. Conclusion : Arthroscopy has a fix place in the algorithm for scaphoid nonunion in our institution. We think an adequate and stabile fixation adopted to the section of the nonunion is indispensable. The distal radius is a sufficient donor-site for cancellous bone grafting. Extra corporal shockwave therapy should be used routinely in scaphoid nonunion. Level of evidence: IV Scaphoid nonunion wrist arthroscopy radius bone graft extra corporal shockwave wrist injuries internal fixation Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Introduction Scaphoid fracture is the most common fracture of the wrist, usually occurring in young, active individuals and may fail to heal because of different reasons [1, 2, 3]. Instability and displacement of the scaphoid leads to impairment of wrist motion and subsequently, to degenerative changes starting on the radial styloid and ending as well-known Scaphoid Nonunion Advanced Collapse (SNAC) Wrist [4]. In 90-100% of non-treated Scaphoid Nonunion (SNU), these degenerative changes can be found five years after injury, accompanied by pain and impaired function [5, 6]. The high rate of SNU and risk of SNAC Wrist, may not only be caused by vascular compromise, but also by the special function of the scaphoid in the carpus, where it links the proximal and the distal rows which allows shearing, bending and promotion forces [7, 8]. The best possibility to prevent the carpal collapse is to restore the scaphoid architecture as soon as possible [1]. The principles for successful treatment of SNU are: excision of pseudarthroses, correction of possible Humpback deformity, bone grafting and rigid internal fixation [1, 9-11]. Open procedures to treat SNU are well known, and results described in the literature, but they necessitate the detachment of parts of capsular and ligamentous structures surrounding the scaphoid, which is covered by cartilage of approximately 80% of its surface [1, 12]. Soft tissue detachment includes the risk of jeopardizing the residual vascularity of the scaphoid, which affects the bone graft healing rate and may lead to wrist stiffness because of scarring [1, 13, 14]. In the last years, arthroscopy (ASK) has become an important technique for diagnosis and treatment of wrist pathologies. It has become the gold standard in exploring the intraarticular conditions of the wrist. Because of rapid advances in technique there is also an increasing use in treatment of bony injuries like scaphoid fractures, distal radius fractures and associated malunions [15, 16]. Use of ASK in SNU was first described in 2006 by Slade and Dodds [17]. Arthroscopy with its minimally invasive approach to the joint surface avoids or minimizes the common complications of open repair including hypertrophic scar formation, avascular necrosis, carpal instability, bone graft infection, screw protrusion and complex regional pain syndrome [18]. Different donor-sites for cancellous bone grafting are described in the literature. Authors use grafts from the ipsilateral radius [9, 13, 19, 20], the olecranon [21] or iliac crest [1, 2]. The use of bone grafting is indisputable, but there are no significant advantages of any of these donor sites described [20]. Additional improvement in blood flow of the scaphoid can be accomplished by focused Extra Corporal Shock Wave Therapy (ESWT). Schleusser et al. described an enhancement in the microcirculation of the scaphoid after single ESWT application [22]. Clinical usage is published in patients with SNU combined with cast fixation [23], as well as in combination with bone grafting and fixation [24], all showing high union rates and good functional outcome. In 2017, we started the treatment of SNU using ASK, radial bone grafting and internal fixation. An interim analysis in 2020 showed sufficient functional benefits after treatment of 24 patients. However, three patients had delayed healing, effectively treated by ESWT and modifying the fixation, and three patients with continuing nonunion who needed vascularized bone grafts for restitution. Analyzing these complications, we adapted our treatment protocol concerning ESWT and internal fixation. The aim of this study is to investigate whether adaption and optimization of the treatment protocol, brought an improvement in outcome of our patients. Material and Methods Approval from institutional ethical review board and informed consent from all patients included in this study was obtained. All patients who underwent arthroscopic treatment of SNU between June 2017 and May 2023 at our facility were enrolled in this study. Inclusion criteria were: (1) Documented SNU for at least six months after failed conservative or operative treatment and after non-treated fractures. (2) Arthroscopic debridement and reduction with bone grafting from the distal radius and internal fixation. (3) available follow-up data for a minimum of 12 months. (4) Patients greater than 16 years at time of treatment. Patients showing a fragmented proximal pole, or radiographic signs of osteoarthritis more than SNAC II, have been excluded. All included patients underwent clinical and radiological examination at least 12 months after surgery. The surgical procedures of these patients have all been performed by two surgeons, experienced in wrist ASK (J.S. and C.W.). Clinical evaluation: Clinical outcome evaluation included pain status based on visual analog scale (VAS), range of motion (ROM), grip strength, nicotine abuse at the time of operation, and post-operative complications. All patients completed Modified Mayo Wrist Score (MMWS) and Disability of the Arm, Shoulder and Hand (DASH) Score questionnaire. Operative specific data including type of fixation and duration of the operative treatment have been assessed, as well as time from fracture to operation. Radiographic evaluation: Standard pre-operative radiographs were obtained in posterior-anterior and lateral views. In all patients Magnetic Resonance Imaging (MRI) was performed pre-operatively to detect vascularization of the proximal pole fragment, as well as Computed Tomography (CT) to analyze the SNU and the structure of the proximal pole to assess according to the Schmidle Classification [14]. Post-operative x-rays were evaluated for possible progression of osteoarthritis in all patients and changes in the scapholunate angle, radiolunate angle and lateral intra scaphoid angle. These measurements were also performed in the last preop x-ray for comparison. Computed tomography was used to confirm bony union. Union was determined by trabeculation across the fracture site of at least 50% in long-axis sagittal CT images. CT was done routinely eight weeks after operation, if union could not be determined, investigation was repeated after four weeks. Surgical procedure: Surgery was performed with the patient under general or regional anesthesia. We used routinely a wrist traction tower with axial load of seven kilograms (kg) and a tourniquet. Standard radiocarpal portals have been 3-4 and 6R and were used to evaluate possible intra-articular pathologies and status of the joint surface. After this midcarpal ulnar portal was created to localize the SNU site and to perform a radial located free-style portal in elongation to the nonunion. The pseudarthrosis was debrided using a 2.7mm shaver, a burr and different angled curettes by this portal. All fibrous tissue and necrotic or sclerotic bony tissue was debrided until healthy cancellous bone was visualized on the proximal and distal fracture sites (Fig. 1). After this a four centimeter (cm) longitudinal incision was made over the distal radius proximal to Listers tubercle. Tendons and muscles were mobilized after incision of the fascia down to the periosteum to create a cortical window and to harvest cancellous bone graft (Fig. 2). After reapproximating the cortical cap, the wound was closed in layers. The arm was then removed from axial load and traction. In patients with Humpback deformity the lunate was reduced and transient fixed by a K-wire in neutral position. If necessary additional K-wires were used as Joysticks to correct the alignment of the scaphoid. Continuation was the same as in non-displaced fractures: A percutaneous guidewire for headless screws was inserted in retrograde fashion under fluoroscopic guidance. Another K-wire was placed parallel to the first to prevent rotation. At this point, the surgeons decided individually if they inserted a third K-wire for fixation or determined the length of the used compression screw. Now the wrist was placed in the traction tower again with axial load to insert the arthroscope in the MU portal to check the position of the K-wires (Fig. 3). A small trocar sheath is used to insert the cancellous bone graft via the MR portal. From this step onwards, it is indispensable to perform a dry ASK. A small freer elevator was used to compress the bone graft in the non-union site until the defect was fully packed (Fig. 4). If used, the headless compression screw (CCSÒ, Medartis, Basel, Switzerland) was inserted in retrograde fashion via the optimal guidewire. The position was confirmed by fluoroscopy. The non-union was re-examined and overlaying bone graft was compressed to the level of the articular surface. In cases of K-wire fixation alone, these were removed when bony union was verified. A rehabilitation protocol was started in all patients after obtaining union. Before the study, a power analysis was performed which determined a cut-off of 5% (0.05) for significant results. The null hypothesis was that the preoperative visual analogue scores, ranges of motion, grip strengths and pinch grips did not change postoperatively, when using two-sided tests. The analyses involved mainly descriptive statistical values. We used nonparametric procedures for statistical comparison between the cases for the visual analogue scales, DASH-score, Mayo wrist score, grip strength and pinch grip to the healthy side. For continuous data and paired samples, a t- test was used. A p -value 0.05 was considered to be statistically significant. Results A total of 52 patients underwent arthroscopic treatment for SNU during the study period. All of these met the inclusion criteria. The average age of the 3 women and 49 men was 21.3 years in whom the dominant hand was involved in 29 patients. We operated 30 right and 22 left wrists (Table 1). The average duration from injury to surgery was 18.6 months (range 6-120 months) and the patients suffered from wrist pain for an average of 8.8 months (range 2-48 months). Only six reported an occupational accident, while the remaining 46 sustained a sport-, bike- or motorbike accident. In pre-operative MRI investigation of 9 patients, we found only slight or no signs of vascularization in the proximal scaphoid pole. Most cases, 31, could be identified as I° after Schmidle [14] in preoperative CT analysis of the proximal pole (Table 2). The exact distribution of the level of SNU can be found in Table 3. The examination of pre-operative X-rays showed mild signs of osteoarthritis on the radial part of the wrist in 7 patients (SNAC I), with no increase in the number or extent of these changes in postoperative follow-up. 23 patients have been treated because of primary scaphoid fracture, 12 with cast immobilization, 7 by ESWT and 4 had fracture fixation by compression-screw and cast immobilization. 12 patients reported nicotine abuse. Fixation of the non-union was performed by compression-screw in 18 (35%), by one screw and 1 K-wire in 19 (36%) and two or three K-wires in 15 (29%) patients. 8 patients showed Humpback-deformity pre-operatively. The Linsheid maneuver was used to correct the intra-scaphoid angle. Average operating time of all 52 patients was 120 min (range 76-190 min) and did not differ significantly to the sub-group treated till 2020, with 124 min (range 92-190 min). Median time to heal was 8.6 weeks (range 6 – 16 weeks). In the whole group we found no postoperative complication except ongoing nonunion as described previously. Interim analysis of the results in 2020 concerning healing, showed three patients with delayed union after 12 weeks, 2 in the waist and 1 in the proximal 1/3 of the scaphoid. All of them were successfully treated by secondary ESWT and modification of the fixation. 3 further patients showed no healing 16 weeks after operation - two in the waist (fixation 1x 1 compression screw, 1x 2 K-wire, Schmidle I° and II°) and one in the proximal 1/3 (2 K-wire, Schmidle II°) , the ongoing SNU was effectively managed using two free vascularized bone grafts and one osteochondral graft from the medial femoral condyle. All three have been in the group with nicotine abuse. The healing rate of these first 24 patients was 87,5% (21 out of 24). In the cohort treated from 2020 to 2023, there has been only one ongoing SNU in a 16-year-old patient and non-union far proximal (fixation 3 K-wires, Schmidle III°). Until now, he shows only small clinical impairment and did not want an osteochondral graft. Healing rate from 2020 to 2023 was 27 out of 28 (96,4%). Cumulative healing rate was 92,3 % (48 out of 52). Progression of pain (VAS) showed a significant improvement as well as DASH score with 32 pre- and 5.4 postoperatively. Similar results could be found concerning Modified Mayo Wrist Score (MMWS) with 47.4 compared to 94.9 postoperatively. Comparing the mean joint angles showed only slight improvements post-operative without significance (Table 4). The ROM and grip force showed comparable results to the contralateral, non-affected wrists in the follow-up. The exact measurement results can be found in Table 5. Discussion Adapting our protocol of arthroscopic treatment of SNU brought an improvement of our results with healing rates rising from 87,5% to 96,4%. This shows a trend, but we could not find a significant statistical difference between the two groups. We will however continue to use our new algorithm. The treatment of SNU varies, but maintaining blood supply, debridement of necrotic bone and scar tissue, exposure of well-vascularized cancellous bone, reduction of the fragments, bone grafting and rigid stabilization are critical requirements [1, 9, 10, 17, 25]. Open debridement and bone grafting offers the advantage of direct visualization of the nonunion and correction of possible deformities of the scaphoid but implicate the stripping of soft tissue attachments from the scaphoid with impairment of bone vascularization and the higher risk of scarring [1, 13, 14, 17, 18]. With respect to this fact arthroscopic treatment of SNU was invited by Slade and Dodds [17]. Because of rising numbers of publications documenting sufficient results of this new method, we started arthroscopic treatment of SNU 2017 in our institution [17, 26, 27]. Until 2020 we found excellent clinical results. The operations were performed by two surgeons but concerning fixation we followed no stringent algorithm. In this period, we found 3 patients with delayed healings, who we could treat sufficiently using ESWT and modifying the fixation and 3 patients, in whom we needed vascularized bone grafts and osteochondral graft from the medial femoral condyle to reach bony union. In the former cases we detected union within 6 weeks. ESWT technology has been used successfully at our institution for more than 20 years in patients with trouble in bone healing. The positive effect of ESWT maintaining scaphoid bone healing is documented clinically [23, 24] as well as in the experimental investigation of Schleusser, who demonstrated a significant increase in capillary flow in scaphoids after single use of ESWT [22]. Furthermore, we changed the fixation to three K-wires in patients affected in the proximal 1/3 and from two K-wires to one compression screw with a K-wire in the middle 1/3 of the other two patients. In 2002 Merrell described in a meta-analysis a significantly higher healing rate using screws for fixation of SNU with 94% compared to K-wires with 77% [28]. In the middle 1/3 for us, using compression screws is the optimal fixation but we use it always in combination with one K-wire or a second screw to neutralize rotational forces [17]. In the proximal section, especially in cases with reduced bony quality like Schmidle II° or III°, we agree with Ecker and use two or three K-wires for fixation in these patients, because the risk of fragmentation of the proximal pole is much higher using screws as well as sufficient anchorage of screws in such a pole fragment is questionable [29]. But to hit the sometimes-small proximal pole with two or three K-wires remains a demanding procedure. In all patients we used autologous cancellous bone from the distal radius, despite Waitayawinyu demonstrating excellent results using olecranon bone grafts [21]. Beside the straightforward procedure using radial bone graft, we think the increase of circulation in the wrist after removing cancellous bone graft, the so called Illaramendi effect, could also be an amplification in healing [30]. Cancellous bone graft from the iliac crest offers a much higher amount of bone but needs a second operation site with demand of general anesthesia and the risk of postoperative pain up to 21% [20, 29, 31]. Garg reported no significant advantage of different donor-sites of cancellous bone concerning functional outcome or healing rate [20]. Our cohort also confirm the findings of Schmidle, who showed a congruence of the healing capacity of SNU with the characteristic of CT scans [14, 32]. These findings are confirmed by Rancy, who also found no sufficient correlation between MRI and histology [33]. We could assess bone union in three patients who showed only minimal or no contrast agent enhancement at the proximal pole in the preoperative MRI but in CT scan a bone quality III° [14, 32]. This is the reason why thin layer CT scan is our leading diagnostic tool pre-operatively to assess the healing capacity. The relevance of MRI in preoperative diagnostic of SNU is judged critically also by other authors. Lin et al. demonstrated healing in patients with avascular necrosis (AVN) in preoperative MRI like in our cohort [34] and agrees with Wong and Ho, who also see no contraindication using ASK in patients with AVN but present no alternative method for sufficient preoperative diagnostic [1]. After analyzing our results 2020 and the successful usage of ESWT and fixation, we changed to a fixed algorithm to treat patients with ASK from there on: patients with non-union in the middle 1/3 have been fixed by two compression screws or one screw and one K-wire (Fig. 5) and those affected in the proximal 1/3 have been fixed by two or three K-wires (Fig. 6). All of them got additionally ESWT (3000 impulses, 0.4 mJ/mm 2 and 4 Hz). The operative technique of ASK, the bone grafting and cast fixation were not modified. In the following period from 2020 to 2023 we treated 28 patients, detecting only one non-union, a 16-year-old patient with very proximal SNU. Analyzing this case, we think, that insufficient fixation of the pole fragment was the reason of treatment failure, as supposed by Ecker in his failure-case [29]. The clinical outcome, grip strength and ROM have been not affected by the modification of our treatment, so we did not distinguish these parameters in two groups. The median time of operations didn’t differ in the two groups, despite the routine use of ESWT, presumably because of the rising routine of the whole team. Sufficient treatment of SNU is the best possibility to avoid the development or progression of SNAC wrist, which can also be confirmed by our data because we found no further signs of osteoarthritis in our patients after a median follow-up of 30 months (range 12 to 73 months) [1]. Shih describes the sufficient use of styloidectomy in 8 of his 44 patients because of ongoing radiocarpal osteoarthritis with satisfactory outcome, a method also possible with use of ASK. But Shih didn’t analyze these 8 cases, Zemirline supposed that remaining Humpback-deformity could cause osteoarthritis despite bony healing and advocates correction of deformity as important step during treatment [35]. ASK also offers the possibility to correct slight Humpback deformity using Linsheid maneuver, which we used in eight patients [19, 35]. The limit of this procedure in our opinion is a fixed flexed position of the distal scaphoid, which cannot be repositioned using K-wires, in such cases we prefer open reduction and cortico-cancellous bone grafting [11, 35-37]. The excellent results of MMWS and DASH Score reflect the good functional outcome after ASK and are confirmed by a significant pain reduction and approximately same ROM (Fig. 7) and strength of the operated wrists compared to the unaffected side. We agree with some authors, who state that ASK provides only minimal trauma to the wrist and because of the minimal scarring, the continuing attachment of the ligament and capsule structures provides excellent functional outcome [1, 2, 9, 34, 37, 38]. Schmidle and Liu postulate to use the least invasive method that is still able to achieve bony healing, so ASK is for us this requested method [13, 14, 32]. Analyzing the four non healed patients brought no clear answers, beside the last, a 16-year-old patient with very proximal SNU with supposed ineffective fixation. In the other three we could not find an explicit reason for the therapy failure; the only common conspicuousness was nicotine abuse. So, we recommend all patients to stop smoking till bony stability and information about nicotine abuse as a risk-factor is a fix point in our pre-treatment consultation. Despite our overall positive results, the sufficient use of vascularized bone grafts, in our cases free vascularized bone grafts and free osteochondral grafts from the medial femoral condyle, are still important in the treatment of SNU. But analyzing the numbers of our operations with the diagnosis SNU in the last years showed an important reduction in use of VBG at our institution. Patients with huge bone defect in the middle 1/3 and fragmented proximal pole (Schmidle IV°) still require VBG or free osteochondral grafts, so it is necessary that these procedures can be done furthermore [33]. Whether you use local VBG or free VBG for salvage is a matter of taste. Despite some authors use local VBG after failure of ASK [9, 33, 39] we suppose that free VBG from the femoral condyle enables the use of a bigger and more solid bone block and the option to rise an osteo-chondral graft. Our impressive overall healing rate of 92.3% is comparable to the results in literature with 88% to 97% [9, 26, 29, 33, 34, 36, 39, 40], despite not excluding patients who have been treated operatively before [9, 26, 36, 39]. On closer inspection the published results we noticed a long time to heal up to 80 weeks [1, 9, 21, 25, 27, 39, 40, 41] for us this poses the question, did we change to VBG to early? Although we cannot answer this question retrospectively, we found a very satisfying median time to heal of 8.6 weeks, shorter than in the literature with 13.2 -18.4 weeks [1, 9, 25, 39-41]. To shorten the sick leave is a very important fact because most of the patients are very young and want to come back to occupation as soon as possible [1, 13, 38, 39]. Considering the results in the literature and our investigation, showing comparable results to open bone grafting which have a higher risk of non-healing [37] and longer time to heal [38], we think ASK is a remarkable technique in treatment of SNU. We are aware of some limitations of our study. Despite the satisfactory total amount of our study cohort, the two subgroups are too small to obtain a significant difference concerning our modified treatment protocol. Due to partial missing pre-operative measurements of grip-strength and ROM, it is not possible to compare these parameters with postoperative results. Although our comparison with the unaffected side shows a good functional outcome. This study demonstrates a retrospective analysis of our results after ASK treatment of SNU and we have no control-group to compare these results. Declarations Author Contribution C. W. wrote the first draft of the manuscript. P. I. and P. J. did most of the follow-up investigations, M. 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J Hand Surg Am 27(4):685-691.https://doi.org/10.1053/jhsu.2002.34372 Ecker J, Shahbaz L, Kohli S, Breidahl W, Andrijich C (2022) Arthroscopic Bone Graft and Internal Fixation of Non-Union of the Proximal Pole of the Scaphoid: Surgical Technique and Outcomes. J Wrist Surg 20;11(6):535-540.https://doi.org/10.1055/s-0041-1742097 Illarramendi AA, Schulz C, De Carli P (2001) The surgical treatment of Kienböck's disease by radius and ulna metaphyseal core decompression. J Hand Surg Am 26(2):252-260.https://doi.org/10.1053/jhsu.2001.22928 Tambe AD, Cutler L, Murali SR, Trail IA, Stanley JK (2006) In scaphoid non-union, does the source of graft affect outcome? Iliac crest versus distal end of radius bone graft. J Hand Surg Br 31(1):47-51.https://doi.org/10.1016/j.jhsb.2005.07.008 Schmidle G, Ebner HL, Klima G, Pfaller K, Fritz J, Hoermann R, Gabl M (2018) Time-dependent changes in bone healing capacity of scaphoid fractures and non-unions. J Anat 232(6):908-918.https://doi.org/10.1111/joa.12795 Rancy SK, Swanstrom MM, DiCarlo EF, Sneag DB, Lee SK, Wolfe SW; Scaphoid Nonunion Consortium (2018) Success of scaphoid nonunion surgery is independent of proximal pole vascularity. J Hand Surg Eur Vol 43(1):32-40.https://doi.org/10.1177/1753193417732003 Lin TY, Fu CW, Tsai PS, Huang CH, Wei SH, Chuang MY (2023) Outcomes after arthroscopic treatment for scaphoid nonunion using ipsilateral radius bone graft and a headless compression screw: a comparison between the patients with and without avascular necrosis. Int Orthop 47(4):1041-1049.https://doi.org/10.1007/s00264-023-05700-5 Zemirline A, Lebailly F, Taleb C, Naito K (2019) Arthroscopic treatment of scaphoid nonunion with humpback deformity and DISI with corticocancellous bone grafting: Technical note. Hand Surg Rehabil 38(5):280-285.https://doi.org/10.1016/j.hansur.2019.07.007 Oh WT, Kang HJ, Chun YM, Koh IH, Lee YJ, Choi YR (2018) Retrospective Comparative Outcomes Analysis of Arthroscopic VersusOpen Bone Graft and Fixation for Unstable Scaphoid Nonunions. Arthroscopy 34(10):2810-2818.https://doi.org/10.1016/j.arthro.2018.04.024 Gvozdenovic R, Kongensgaard TB (2023) Results of arthroscopic cancellous bone grafting for treatment of scaphoid nonunion in comparison with open cancellous bone grafting. J Hand Surg Eur Vol 48(9):903-910.https://doi.org/10.1177/17531934231166343 Kjaer M, Rasmussen JV, Gvozdenovic R (2023) Arthroscopic versus open cancellous bone grafting for scaphoid delayed/nonunion in adults (SCOPE-OUT): study protocol for a randomized clinical trial. Trials 14;24(1):273.https://doi.org/10.1186/s13063-023-07281-5 Shih YC, Wu CC, Shih JT (2023) Arthroscopic treatment of stable nonunion, unstable nonunion, or nonunionof the scaphoid with early degenerative radioscaphoid arthritis. J Orthop Surg Res 21;18(1):123.https://doi.org/10.1186/s13018-023-03609-8 Wang JP, Huang HK, Shih JT (2020) Arthroscopic-assisted reduction, bone grafting and screw fixation across the scapholunate joint for proximal pole scaphoid nonunion. BMC Musculoskelet Disord 10;21(1):834.https://doi.org/10.1186/s12891-020-03850-w Cheng C, Jiang Z, Sun H, Hu J, Ouyang Y (2023) Arthroscopic treatment of unstable scaphoid fracture and nonunion with two headless compression screws and distal radius bone graft. J Orthop Surg Res 18;18(1):52.https://doi.org/10.1186/s13018-023-03529-7 Tables Table 1, Demographic data of patients Age (years) 21.3 (16-38) Duration of SNU (months) 18.6 (6-120) Duration of pain (months) 8.8 (2-48) Sex Female/Male 3/49 Rhight/left hand 30/22 SNU Scaphoid Non Union Table 2, Schmidle classification CT-Classification I II III 31 (59.6%) 19 (36.5%) 2 (3.9%) Schmidle et al. [14] Table 3, Level of Scaphoid nonunion Level of non union 2017-2020 2020-2023 total Distal 1/3 0 (0%) 0 (0%) 0 (0%) Waist 18 (34.6%) 16 (30.8%) 34 (65.4%) Proximal 1/3 4 (7.8%) 14 (26.9%) 18 (34.6%) Table 4, Outcome after arthroscopic treatment of Scaphoid nonunion Outcome evaluation Pre-operative mean (min/max) Follow-up mean (min/max) VAS pain score 2.7 (1.2/5.7) 0.7 (0/3) DASH Score 32 (0.5/68.5) 5.4 (0.5/35) MMWS 47.4 (20/90) 94.9 (60/100) S-L angle 54.9° (41°/75°) 54.1° (45°/67°) R-L angle 14.3° (5°/36°) 13.2° (5°/30°) Intrascaphoid angle 49° (25°-77°) 45° (20°-70°) VAS visual analogue scale, MMWS Modified Mayo Wrist Score Table 4, Outcome after arthroscopic treatment of Scaphoid nonunion Outcome evaluation Pre-operative mean (min/max) Follow-up mean (min/max) VAS pain score 2.7 (1.2/5.7) 0.7 (0/3) DASH Score 32 (0.5/68.5) 5.4 (0.5/35) MMWS 47.4 (20/90) 94.9 (60/100) S-L angle 54.9° (41°/75°) 54.1° (45°/67°) R-L angle 14.3° (5°/36°) 13.2° (5°/30°) Intrascaphoid angle 49° (25°-77°) 45° (20°-70°) VAS visual analogue scale, MMWS Modified Mayo Wrist Score Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 19 Feb, 2025 Read the published version in Archives of Orthopaedic and Trauma Surgery → Version 1 posted Editorial decision: Revision requested 10 Jan, 2025 Reviews received at journal 07 Jan, 2025 Reviewers agreed at journal 01 Jan, 2025 Reviews received at journal 31 Dec, 2024 Reviewers agreed at journal 31 Dec, 2024 Reviewers invited by journal 30 Dec, 2024 Editor assigned by journal 30 Dec, 2024 Submission checks completed at journal 30 Dec, 2024 First submitted to journal 23 Dec, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5697154","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":396253882,"identity":"fe57f931-a108-4d64-a22a-c39d8d1d8167","order_by":0,"name":"Christian Windhofer","email":"data:image/png;base64,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","orcid":"","institution":"Unfallkrankenhaus Salzburg","correspondingAuthor":true,"prefix":"","firstName":"Christian","middleName":"","lastName":"Windhofer","suffix":""},{"id":396253883,"identity":"961de4c9-7886-4ab3-b8f9-5fb1ca30115b","order_by":1,"name":"Patrik Ivusic","email":"","orcid":"","institution":"Unfallkrankenhaus Salzburg","correspondingAuthor":false,"prefix":"","firstName":"Patrik","middleName":"","lastName":"Ivusic","suffix":""},{"id":396253884,"identity":"70e7b3d0-ab60-41c9-bc62-5e8191a646c8","order_by":2,"name":"Peter Jakob","email":"","orcid":"","institution":"Krankenhaus der Barmherzigen Schwestern Ried","correspondingAuthor":false,"prefix":"","firstName":"Peter","middleName":"","lastName":"Jakob","suffix":""},{"id":396253885,"identity":"3ab42457-3a30-4c10-a0b8-ced3a9ee9ae8","order_by":3,"name":"Markus Lill","email":"","orcid":"","institution":"Unfallkrankenhaus Salzburg","correspondingAuthor":false,"prefix":"","firstName":"Markus","middleName":"","lastName":"Lill","suffix":""},{"id":396253886,"identity":"9f49598e-6f80-4921-91ed-198e40b1de0e","order_by":4,"name":"Josef Schauer","email":"","orcid":"","institution":"Salzburger Landeskliniken","correspondingAuthor":false,"prefix":"","firstName":"Josef","middleName":"","lastName":"Schauer","suffix":""}],"badges":[],"createdAt":"2024-12-23 06:53:27","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5697154/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5697154/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00402-025-05777-0","type":"published","date":"2025-02-19T15:56:51+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":72739025,"identity":"04a565b1-9a75-478b-b445-7036ffe80887","added_by":"auto","created_at":"2025-01-01 09:23:04","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1437309,"visible":true,"origin":"","legend":"\u003cp\u003eArthroscopic findings of a SNU, pictures done from the midcarpal-ulnar portal.\u003c/p\u003e\n\u003cp\u003ea Nonunion with scare tissue. b Debridement using a 2.7mm Shaver.\u003c/p\u003e\n\u003cp\u003ec Debridement using a curette. d Cancellous bone at the distal nonunion site after adequate debridement.\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5697154/v1/5482a9795af384176b76749e.jpg"},{"id":72739020,"identity":"a535cf13-60c4-4cda-acfa-feb37b0c86fd","added_by":"auto","created_at":"2025-01-01 09:23:04","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":86751,"visible":true,"origin":"","legend":"\u003cp\u003eHarvesting of cancellous bone graft from the distal radius over a square cortical window. The wrist is still held in the traction tower.\u003c/p\u003e","description":"","filename":"Figure2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5697154/v1/9a5aa175d34f2afab637d751.jpeg"},{"id":72740377,"identity":"0af2d3aa-74f8-4076-9d8a-70065af16f14","added_by":"auto","created_at":"2025-01-01 09:31:04","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":126004,"visible":true,"origin":"","legend":"\u003cp\u003eThe position of the K-wires can be checked after drilling under fluoroscopy visually. After temporary opening the torniquet, bleeding points demonstrate adequate debridement to vital tissue.\u003c/p\u003e","description":"","filename":"Figure3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5697154/v1/fc160c8dcf396e564260422a.jpeg"},{"id":72740405,"identity":"b526f482-afbb-40bd-8d65-f5ca3782c364","added_by":"auto","created_at":"2025-01-01 09:31:05","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":69247,"visible":true,"origin":"","legend":"\u003cp\u003eInsertion of cancellous bone graft into the nonunion site.\u003c/p\u003e\n\u003cp\u003ea Cancellous bone is placed using a small trocar sheath.\u003c/p\u003e\n\u003cp\u003eb After each portion, the bone is compressed using a small elevator.\u003c/p\u003e\n\u003cp\u003ec Fully packed nonunion site.\u003c/p\u003e","description":"","filename":"Figure4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5697154/v1/dc1fbafe7834c17e7dc0cb12.jpeg"},{"id":72739047,"identity":"f9062a6e-83c7-41ba-b558-c8aebee03c35","added_by":"auto","created_at":"2025-01-01 09:23:06","extension":"jpeg","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":227185,"visible":true,"origin":"","legend":"\u003cp\u003eShowing a patient with SNU in the middle 1/3 of the scaphoid.\u003c/p\u003e\n\u003cp\u003ea and b Preoperative CT scan showing the nonunion with bone resorption and slight Humpback-deformity.\u003c/p\u003e\n\u003cp\u003ec and d Intraoperative fluoroscopy after bone grafting and fixation with 2 headless compressions screws.\u003c/p\u003e\n\u003cp\u003ee and f CT scan, done 10 weeks after operation showing bony union.\u003c/p\u003e","description":"","filename":"Figure5.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5697154/v1/785f6b59a3282737dff07752.jpeg"},{"id":72739030,"identity":"34aa638a-5d53-4dd0-83e0-f78b9319e491","added_by":"auto","created_at":"2025-01-01 09:23:05","extension":"jpeg","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":158263,"visible":true,"origin":"","legend":"\u003cp\u003eScaphoid nonunion at the proximal 1/3, treated with radial bone graft and K-wires.\u003c/p\u003e\n\u003cp\u003ea and b Preoperative CT-scan showing the SNU.\u003c/p\u003e\n\u003cp\u003ec Intraoperative fluoroscopy after positioning of the 3 K-wires. The tip of the rod is used to mark the position where the ESWT is applicated.\u003c/p\u003e\n\u003cp\u003ed and e CT-scan after 10 weeks demonstrating bony union with K-wires in situ.\u003c/p\u003e\n\u003cp\u003ef and g Posterior-anterior and lateral x-rays after removal of the K-wires.\u003c/p\u003e","description":"","filename":"Figure6.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5697154/v1/308ee158ce3c05a676334499.jpeg"},{"id":72740407,"identity":"489130e5-52ac-493a-8ade-baa088aa206d","added_by":"auto","created_at":"2025-01-01 09:31:06","extension":"jpg","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":1333080,"visible":true,"origin":"","legend":"\u003cp\u003eClinical outcome of a 26-year-old patient, 4 months after ASK.\u003c/p\u003e\n\u003cp\u003ea, b and c ROM with slight limitation of the operated right wrist.\u003c/p\u003e\n\u003cp\u003ed The ASK portals and scar on the distal dorsal radius after raising of cancellous bone graft (marked by the star) are rarely to see.\u003c/p\u003e","description":"","filename":"Figure7.jpg","url":"https://assets-eu.researchsquare.com/files/rs-5697154/v1/d3fe8559c6e7ef04f8f388ba.jpg"},{"id":77052444,"identity":"d068069a-d9a8-4182-93a0-679cd9f7e218","added_by":"auto","created_at":"2025-02-24 16:00:36","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3939935,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5697154/v1/2616e85a-74e6-49ba-ada8-20b504fe5545.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Arthroscopic treatment of scaphoid nonunion, a new algorithm after six years practice","fulltext":[{"header":"Introduction","content":"\u003cp\u003eScaphoid fracture is the most common fracture of the wrist, usually occurring in young, active individuals and may fail to heal because of different reasons\u0026nbsp;[1, 2, 3]. Instability and displacement of the scaphoid leads to impairment of wrist motion and subsequently, to degenerative changes starting on the radial styloid and ending as well-known Scaphoid Nonunion Advanced Collapse (SNAC) Wrist \u0026nbsp;[4]. In 90-100% of non-treated Scaphoid Nonunion (SNU), these degenerative changes can be found five years after injury, accompanied by pain and impaired function\u0026nbsp;[5, 6]. The high rate of SNU and risk of SNAC Wrist, may not only be caused by vascular compromise, but also by the special function of the scaphoid in the carpus, where it links the proximal and the distal rows which allows shearing, bending and promotion forces\u0026nbsp;[7, 8].\u003c/p\u003e\n\u003cp\u003eThe best possibility to prevent the carpal collapse is to restore the scaphoid architecture as soon as possible\u0026nbsp;[1].\u003c/p\u003e\n\u003cp\u003eThe principles for successful treatment of SNU are: excision of pseudarthroses, correction of possible Humpback deformity, bone grafting and rigid internal fixation\u0026nbsp;[1, 9-11].\u003c/p\u003e\n\u003cp\u003eOpen procedures to treat SNU are well known, and results described in the literature, but they necessitate the detachment of parts of capsular and ligamentous structures surrounding the scaphoid, which is covered by cartilage of approximately 80% of its surface\u0026nbsp;[1, 12]. Soft tissue detachment includes the risk of jeopardizing the residual vascularity of the scaphoid, which affects the bone graft healing rate and may lead to wrist stiffness because of scarring\u0026nbsp;[1, 13, 14].\u003c/p\u003e\n\u003cp\u003eIn the last years, arthroscopy (ASK) has become an important technique for diagnosis and treatment of wrist pathologies. It has become the gold standard in exploring the intraarticular conditions of the wrist. Because of rapid advances in technique there is also an increasing use in treatment of bony injuries like scaphoid fractures, distal radius fractures and associated malunions\u0026nbsp;[15, 16].\u003c/p\u003e\n\u003cp\u003eUse of ASK in SNU was first described in 2006 by Slade and Dodds\u0026nbsp;[17]. Arthroscopy with its minimally invasive approach to the joint surface avoids or minimizes the common complications of open repair including hypertrophic scar formation, avascular necrosis, carpal instability, bone graft infection, screw protrusion and complex regional pain syndrome\u0026nbsp;[18].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDifferent donor-sites for cancellous bone grafting are described in the literature. Authors use grafts from the ipsilateral radius\u0026nbsp;[9, 13, 19, 20], the olecranon\u0026nbsp;[21]\u0026nbsp;or iliac crest\u0026nbsp;[1, 2]. The use of bone grafting is indisputable, but there are no significant advantages of any of these donor sites described\u0026nbsp;[20].\u003c/p\u003e\n\u003cp\u003eAdditional improvement in blood flow of the scaphoid can be accomplished by focused Extra Corporal Shock Wave Therapy (ESWT). Schleusser et al. described an enhancement in the microcirculation of the scaphoid after single ESWT application\u0026nbsp;[22]. Clinical usage is published in patients with SNU combined with cast fixation\u0026nbsp;[23], as well as in combination with bone grafting and fixation\u0026nbsp;[24], all showing high union rates and good functional outcome.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn 2017, we started the treatment of SNU using ASK, radial bone grafting and internal fixation. An interim analysis in 2020 showed sufficient functional benefits after treatment of 24 patients. However, three patients had delayed healing, effectively treated by ESWT and modifying the fixation, and three patients with continuing nonunion who needed vascularized bone grafts for restitution.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAnalyzing these complications, we adapted our treatment protocol concerning ESWT and internal fixation.\u003c/p\u003e\n\u003cp\u003eThe aim of this study is to investigate whether adaption and optimization of the treatment protocol, brought an improvement in outcome of our patients.\u003c/p\u003e"},{"header":"Material and Methods","content":"\u003cp\u003eApproval from institutional ethical review board and informed consent from all patients included in this study was obtained.\u003c/p\u003e\n\u003cp\u003eAll patients who underwent arthroscopic treatment of SNU between June 2017 and May 2023 at our facility were enrolled in this study.\u003c/p\u003e\n\u003cp\u003eInclusion criteria were: (1) Documented SNU for at least six months after failed conservative or operative treatment and after non-treated fractures. (2) Arthroscopic debridement and reduction with bone grafting from the distal radius and internal fixation. (3) available follow-up data for a minimum of 12 months. (4) Patients greater than 16 years at time of treatment.\u003c/p\u003e\n\u003cp\u003ePatients showing a fragmented proximal pole, or radiographic signs of osteoarthritis more than SNAC II, have been excluded.\u003c/p\u003e\n\u003cp\u003eAll included patients underwent clinical and radiological examination at least 12 months after surgery.\u003c/p\u003e\n\u003cp\u003eThe surgical procedures of these patients have all been performed by two surgeons, experienced in wrist ASK (J.S. and C.W.).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical evaluation:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eClinical outcome evaluation included pain status based on visual analog scale (VAS), range of motion (ROM), grip strength, nicotine abuse at the time of operation, and post-operative complications. All patients completed Modified Mayo Wrist Score (MMWS) and Disability of the Arm, Shoulder and Hand (DASH) Score questionnaire. Operative specific data including type of fixation and duration of the operative treatment have been assessed, as well as time from fracture to operation.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRadiographic evaluation:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eStandard pre-operative radiographs were obtained in posterior-anterior and lateral views.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn all patients Magnetic Resonance Imaging (MRI) was performed pre-operatively to detect vascularization of the proximal pole fragment, as well as Computed Tomography (CT) to analyze the SNU and the structure of the proximal pole to assess according to the Schmidle Classification\u0026nbsp;[14].\u003c/p\u003e\n\u003cp\u003ePost-operative x-rays were evaluated for possible progression of osteoarthritis in all patients and changes in the scapholunate angle, radiolunate angle and lateral intra scaphoid angle. These measurements were also performed in the last preop x-ray for comparison.\u003c/p\u003e\n\u003cp\u003eComputed tomography was used to confirm bony union. Union was determined by trabeculation across the fracture site of at least 50% in long-axis sagittal CT images. CT was done routinely eight weeks after operation, if union could not be determined, investigation was repeated after four weeks.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSurgical procedure:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSurgery was performed with the patient under general or regional anesthesia. We used routinely a wrist traction tower with axial load of seven kilograms (kg) and a tourniquet. Standard radiocarpal portals have been 3-4 and 6R and were used to evaluate possible intra-articular pathologies and status of the joint surface.\u003c/p\u003e\n\u003cp\u003eAfter this midcarpal ulnar portal was created to localize the SNU site and to perform a radial located free-style portal in elongation to the nonunion. The pseudarthrosis was debrided using a 2.7mm shaver, a burr and different angled curettes by this portal. All fibrous tissue and necrotic or sclerotic bony tissue was debrided until healthy cancellous bone was visualized on the proximal and distal fracture sites (Fig. 1).\u003c/p\u003e\n\u003cp\u003eAfter this a four centimeter (cm) longitudinal incision was made over the distal radius proximal to Listers tubercle. Tendons and muscles were mobilized after incision of the fascia down to the periosteum to create a cortical window and to harvest cancellous bone graft (Fig. 2).\u0026nbsp;After reapproximating the cortical cap, the wound was closed in layers.\u003c/p\u003e\n\u003cp\u003eThe arm was then removed from axial load and traction. In patients with Humpback deformity the lunate was reduced and transient fixed by a K-wire in neutral position. If necessary additional K-wires were used as Joysticks to correct the alignment of the scaphoid. Continuation was the same as in non-displaced fractures: A percutaneous guidewire for headless screws was inserted in retrograde fashion under fluoroscopic guidance. Another K-wire was placed parallel to the first to prevent rotation. At this point, the surgeons decided individually if they inserted a third K-wire for fixation or determined the length of the used compression screw.\u003c/p\u003e\n\u003cp\u003eNow the wrist was placed in the traction tower again with axial load to insert the arthroscope in the MU portal to check the position of the K-wires (Fig. 3). A small trocar sheath is used to insert the cancellous bone graft via the MR portal. From this step onwards, it is indispensable to perform a dry ASK. A small freer elevator was used to compress the bone graft in the non-union site until the defect was fully packed (Fig. 4). If used, the headless compression screw (CCS\u0026Ograve;, Medartis, Basel, Switzerland) was inserted in retrograde fashion via the optimal guidewire. The position was confirmed by fluoroscopy. The non-union was re-examined and overlaying bone graft was compressed to the level of the articular surface.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn cases of K-wire fixation alone, these were removed when bony union was verified.\u003c/p\u003e\n\u003cp\u003eA rehabilitation protocol was started in all patients after obtaining union.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eBefore the study, a power analysis was performed which determined a cut-off of 5% (0.05) for significant results.\u0026nbsp;The null hypothesis\u0026nbsp;was that the preoperative visual analogue scores, ranges of motion, grip strengths and pinch grips did not change postoperatively, when using two-sided tests.\u003c/p\u003e\n\u003cp\u003eThe analyses involved mainly descriptive statistical values. We used nonparametric procedures for statistical comparison between the cases for the visual analogue scales, DASH-score, Mayo wrist score, grip strength and pinch grip to the healthy side. For continuous data and paired samples, a t- test was used. \u0026nbsp;A \u003cem\u003ep\u003c/em\u003e-value 0.05 was considered to be statistically significant. \u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eA total of 52 patients underwent arthroscopic treatment for SNU during the study period. All of these met the inclusion criteria. The average age of the 3 women and 49 men was 21.3 years in whom the dominant hand was involved in 29 patients. We operated 30 right and 22 left wrists (Table 1).\u0026nbsp;The average duration from injury to surgery was 18.6 months (range 6-120 months) and the patients suffered from wrist pain for an average of 8.8 months (range 2-48 months). Only six reported an occupational accident, while the remaining 46 sustained a sport-, bike- or motorbike accident.\u003c/p\u003e\n\u003cp\u003eIn pre-operative MRI investigation of 9 patients, we found only slight or no signs of vascularization in the proximal scaphoid pole. Most cases, 31, could be identified as I\u0026deg; after Schmidle\u0026nbsp;[14]\u0026nbsp;in preoperative CT analysis of the proximal pole (Table 2). The exact distribution of the level of SNU can be found in Table 3. The examination of pre-operative X-rays showed mild signs of osteoarthritis on the radial part of the wrist in 7 patients (SNAC I), with no increase in the number or extent of these changes in postoperative follow-up. 23 patients have been treated because of primary scaphoid fracture, 12 with cast immobilization, 7 by ESWT and 4 had fracture fixation by compression-screw and cast immobilization.\u003c/p\u003e\n\u003cp\u003e12 patients reported nicotine abuse.\u003c/p\u003e\n\u003cp\u003eFixation of the non-union was performed by compression-screw in 18 (35%), by one screw and 1 K-wire in 19 (36%) and two or three K-wires in 15 (29%) patients. 8 patients showed Humpback-deformity pre-operatively. The Linsheid maneuver was used to correct the intra-scaphoid angle. \u0026nbsp;Average operating time of all 52 patients was 120 min (range 76-190 min) and did not differ significantly to the sub-group treated till 2020, with 124 min (range 92-190 min). Median time to heal was 8.6 weeks (range 6 \u0026ndash; 16 weeks). In the whole group we found no postoperative complication except ongoing nonunion as described previously.\u003c/p\u003e\n\u003cp\u003eInterim analysis of the results in 2020 concerning healing, showed three patients with delayed union after 12 weeks, 2 in the waist and 1 in the proximal 1/3 of the scaphoid.\u0026nbsp;All of them were successfully treated by secondary ESWT and modification of the fixation. 3 further patients showed no healing 16 weeks after operation - two in the waist (fixation 1x 1 compression screw, 1x 2 K-wire, Schmidle I\u0026deg; and II\u0026deg;) and one in the proximal 1/3 (2 K-wire, Schmidle II\u0026deg;)\u003cs\u003e,\u003c/s\u003e the ongoing SNU was effectively managed using two free vascularized bone grafts and one osteochondral graft from the medial femoral condyle. All three have been in the group with nicotine abuse.\u003c/p\u003e\n\u003cp\u003eThe healing rate of these first 24 patients was 87,5% (21 out of 24). In the cohort treated from 2020 to 2023, there has been only one ongoing SNU in a 16-year-old patient and non-union far proximal (fixation 3 K-wires, Schmidle III\u0026deg;). Until now, he shows only small clinical impairment and did not want an osteochondral graft. Healing rate from 2020 to 2023 was 27 out of 28 (96,4%). Cumulative healing rate was 92,3 % (48 out of 52).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eProgression of pain (VAS) showed a significant improvement as well as DASH score with 32 pre- and 5.4 postoperatively. Similar results could be found concerning Modified Mayo Wrist Score (MMWS) with 47.4 compared to 94.9 postoperatively. Comparing the mean joint angles showed only slight improvements post-operative without significance (Table 4).\u003c/p\u003e\n\u003cp\u003eThe ROM and grip force showed comparable results to the contralateral, non-affected wrists in the follow-up. The exact measurement results can be found in Table 5.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eAdapting our protocol of arthroscopic treatment of SNU brought an improvement of our results with healing rates rising from 87,5% to 96,4%. This shows a trend, but we could not find a significant statistical difference between the two groups. \u0026nbsp;We will however continue to use our new algorithm.\u003c/p\u003e\n\u003cp\u003eThe treatment of SNU varies, but maintaining blood supply, debridement of necrotic bone and scar tissue, exposure of well-vascularized cancellous bone, reduction of the fragments, bone grafting and rigid stabilization are critical requirements\u0026nbsp;[1, 9, 10, 17, 25].\u003c/p\u003e\n\u003cp\u003eOpen debridement and bone grafting offers the advantage of direct visualization of the nonunion and correction of possible deformities of the scaphoid but implicate the stripping of soft tissue attachments from the scaphoid with impairment of bone vascularization and the higher risk of scarring\u0026nbsp;[1, 13, 14, 17, 18]. With respect to this fact arthroscopic treatment of SNU was invited by Slade and Dodds\u0026nbsp;[17].\u003c/p\u003e\n\u003cp\u003eBecause of rising numbers of publications documenting sufficient results of this new method, we started arthroscopic treatment of SNU 2017 in our institution\u0026nbsp;[17, 26, 27]. Until 2020 we found excellent clinical results. The operations were performed by two surgeons but concerning fixation we followed no stringent algorithm. In this period, we found 3 patients with delayed healings, who we could treat sufficiently using ESWT and modifying the fixation and 3 patients, in whom we needed vascularized bone grafts and osteochondral graft from the medial femoral condyle to reach bony union.\u003c/p\u003e\n\u003cp\u003eIn the former cases we detected union within 6 weeks. ESWT technology has been used successfully at our institution for more than 20 years in patients with trouble in bone healing. The positive effect of ESWT maintaining scaphoid bone healing is documented clinically\u0026nbsp;[23, 24]\u0026nbsp;as well as in the experimental investigation of Schleusser, who demonstrated a significant increase in capillary flow in scaphoids after single use of ESWT\u0026nbsp;[22]. Furthermore, we changed the fixation to three K-wires in patients affected in the proximal 1/3 and from two K-wires to one compression screw with a K-wire in the middle 1/3 of the other two patients. In 2002 Merrell described in a meta-analysis a significantly higher healing rate using screws for fixation of SNU with 94% compared to K-wires with 77%\u0026nbsp;[28]. In the middle 1/3 for us, using compression screws is the optimal fixation but we use it always in combination with one K-wire or a second screw to neutralize rotational forces\u0026nbsp;[17]. In the proximal section, especially in cases with reduced bony quality like Schmidle II\u0026deg; or III\u0026deg;, we agree with Ecker and use two or three K-wires for fixation in these patients, because the risk of fragmentation of the proximal pole is much higher using screws as well as sufficient anchorage of screws in such a pole fragment is questionable\u0026nbsp;[29]. But to hit the sometimes-small proximal pole with two or three K-wires remains a demanding procedure.\u003c/p\u003e\n\u003cp\u003eIn all patients we used autologous cancellous bone from the distal radius, despite Waitayawinyu demonstrating excellent results using olecranon bone grafts\u0026nbsp;[21]. Beside the straightforward procedure using radial bone graft, we think the increase of circulation in the wrist after removing cancellous bone graft, the so called Illaramendi effect, could also be an amplification in healing [30].\u0026nbsp;Cancellous bone graft from the iliac crest offers a much higher amount of bone but needs a second operation site with demand of general anesthesia and the risk of postoperative pain up to 21%\u0026nbsp;[20, 29, 31]. Garg reported no significant advantage of different donor-sites of cancellous bone concerning functional outcome or healing rate\u0026nbsp;[20].\u003c/p\u003e\n\u003cp\u003eOur cohort also confirm the findings of Schmidle, who showed a congruence of the healing capacity of SNU with the characteristic of CT scans\u0026nbsp;[14, 32]. These findings are confirmed by Rancy, who also found no sufficient correlation between MRI and histology\u0026nbsp;[33]. We could assess bone union in three patients who showed only minimal or no contrast agent enhancement at the proximal pole in the preoperative MRI but in CT scan a bone quality III\u0026deg;\u0026nbsp;[14, 32]. This is the reason why thin layer CT scan is our leading diagnostic tool pre-operatively to assess the healing capacity. The relevance of MRI in preoperative diagnostic of SNU is judged critically also by other authors. Lin et al. \u0026nbsp;demonstrated healing in patients with avascular necrosis (AVN) in preoperative MRI like in our cohort\u0026nbsp;[34]\u0026nbsp;and agrees with Wong and Ho, who also see no contraindication using ASK in patients with AVN but present no alternative method for sufficient preoperative diagnostic\u0026nbsp;[1].\u003c/p\u003e\n\u003cp\u003eAfter analyzing our results 2020 and the successful usage of ESWT and fixation, we changed to a fixed algorithm to treat patients with ASK from there on: patients with non-union in the middle 1/3 have been fixed by two compression screws or one screw and one K-wire (Fig. 5)\u0026nbsp;and those affected in the proximal 1/3 have been fixed by two or three K-wires (Fig. 6).\u0026nbsp;All of them got additionally ESWT (3000 impulses, 0.4 mJ/mm\u003csup\u003e2\u003c/sup\u003e and 4 Hz). The operative technique of ASK, the bone grafting and cast fixation were not modified.\u003c/p\u003e\n\u003cp\u003eIn the following period from 2020 to 2023 we treated 28 patients, detecting only one non-union, a 16-year-old patient with very proximal SNU. Analyzing this case, we think, that insufficient fixation of the pole fragment was the reason of treatment failure, as supposed by Ecker in his failure-case\u0026nbsp;[29].\u003c/p\u003e\n\u003cp\u003eThe clinical outcome, grip strength and ROM have been not affected by the modification of our treatment, so we did not distinguish these parameters in two groups. The median time of operations didn\u0026rsquo;t differ in the two groups, despite the routine use of ESWT, presumably because of the rising routine of the whole team.\u003c/p\u003e\n\u003cp\u003eSufficient treatment of SNU is the best possibility to avoid the development or progression of SNAC wrist, which can also be confirmed by our data because we found no further signs of osteoarthritis in our patients after a median follow-up of 30 months (range 12 to 73 months)\u0026nbsp;[1]. Shih describes the sufficient use of styloidectomy in 8 of his 44 patients because of ongoing radiocarpal osteoarthritis with satisfactory outcome, a method also possible with use of ASK. But Shih didn\u0026rsquo;t analyze these 8 cases, Zemirline supposed that remaining Humpback-deformity could cause osteoarthritis despite bony healing and advocates correction of deformity as important step during treatment\u0026nbsp;[35].\u003c/p\u003e\n\u003cp\u003eASK also offers the possibility to correct slight Humpback deformity using Linsheid maneuver, which we used in eight patients\u0026nbsp;[19, 35]. The limit of this procedure in our opinion is a fixed flexed position of the distal scaphoid, which cannot be repositioned using K-wires, in such cases we prefer open reduction and cortico-cancellous bone grafting\u0026nbsp;[11, 35-37].\u003c/p\u003e\n\u003cp\u003eThe excellent results of MMWS and DASH Score reflect the good functional outcome after ASK and are confirmed by a significant pain reduction and approximately same ROM (Fig. 7) and strength of the operated wrists compared to the unaffected side. We agree with some authors, who state that ASK provides only minimal trauma to the wrist and because of the minimal scarring, the continuing attachment of the ligament and capsule structures provides excellent functional outcome\u0026nbsp;[1, 2, 9, 34, 37, 38]. Schmidle and Liu postulate to use the least invasive method that is still able to achieve bony healing, so ASK is for us this requested method\u0026nbsp;[13, 14, 32].\u003c/p\u003e\n\u003cp\u003eAnalyzing the four non healed patients brought no clear answers, beside the last, a 16-year-old patient with very proximal SNU with supposed ineffective fixation. In the other three we could not find an explicit reason for the therapy failure; the only common conspicuousness was nicotine abuse. So, we recommend all patients to stop smoking till bony stability and information about nicotine abuse as a risk-factor is a fix point in our pre-treatment consultation.\u003c/p\u003e\n\u003cp\u003eDespite our overall positive results, the sufficient use of vascularized bone grafts, in our cases free vascularized bone grafts and free osteochondral grafts from the medial femoral condyle, are still important in the treatment of SNU. But analyzing the numbers of our operations with the diagnosis SNU in the last years showed an important reduction in use of VBG at our institution. Patients with huge bone defect in the middle 1/3 and fragmented proximal pole (Schmidle IV\u0026deg;) still require VBG or free osteochondral grafts, so it is necessary that these procedures can be done furthermore\u0026nbsp;[33]. \u0026nbsp; Whether you use local VBG or free VBG for salvage is a matter of taste. Despite some authors use local VBG after failure of ASK\u0026nbsp;[9, 33, 39]\u0026nbsp;we suppose that free VBG from the femoral condyle enables the use of a bigger and more solid bone block and the option to rise an osteo-chondral graft.\u003c/p\u003e\n\u003cp\u003eOur impressive overall healing rate of 92.3% is comparable to the results in literature with 88% to 97%\u0026nbsp;[9, 26, 29, 33, 34, 36, 39, 40], despite not excluding patients who have been treated operatively before\u0026nbsp;[9, 26, 36, 39]. On closer inspection the published results we noticed a long time to heal up to 80 weeks\u0026nbsp;[1, 9, 21, 25, 27, 39, 40, 41]\u0026nbsp;for us this poses the question, did we change to VBG to early? Although we cannot answer this question retrospectively, we found a very satisfying median time to heal of 8.6 weeks, shorter than in the literature with 13.2 -18.4 weeks [1, 9, 25, 39-41].\u0026nbsp;To shorten the sick leave is a very important fact because most of the patients are very young and want to come back to occupation as soon as possible\u0026nbsp;[1, 13, 38, 39].\u003c/p\u003e\n\u003cp\u003eConsidering the results in the literature and our investigation, showing comparable results to open bone grafting which have a higher risk of non-healing\u0026nbsp;[37]\u0026nbsp;and longer time to heal\u0026nbsp;[38], we think ASK is a remarkable technique in treatment of SNU.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWe are aware of some limitations of our study. Despite the satisfactory total amount of our study cohort, the two subgroups are too small to obtain a significant difference concerning our modified treatment protocol. Due to partial missing pre-operative measurements of grip-strength and ROM, it is not possible to compare these parameters with postoperative results. Although our comparison with the unaffected side shows a good functional outcome. \u0026nbsp;This study demonstrates a retrospective analysis of our results after ASK treatment of SNU and we have no control-group to compare these results.\u0026nbsp;\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eC. W. wrote the first draft of the manuscript. P. I. and P. J. did most of the follow-up investigations, M. L. reviewed the manuscript and implemented a part of the discussion, J. Sch. has been one of the two surgeons and reviewed the manuscript. All authors reviewed and edited the manuscript and approved the final version of the manuscript\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe authors thank Chris Lockie, MD, for revision of this paper concerning English language and Christoph Hirnsperger, MD, for preparing the figures.\u003c/p\u003e\u003cp\u003eNo funding was received to assist with the preparation of this manuscript.\u003c/p\u003e\n\u003cp\u003eAll authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eWong WC, Ho PC (2019) Arthroscopic Management of Scaphoid Nonunion. Hand Clin 35:295-313.https://doi:org/10.1016/j.hcl.2019.03.003\u003c/li\u003e\n \u003cli\u003eHaugstvedt JR, Wong CW (2020) Arthroscopic treatment for nonunion of the scaphoid. 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Arch Orthop Trauma Surg 143(7):4565-4574.https://doi.org/10.1007/s00402-023-04806-0\u003c/li\u003e\n \u003cli\u003eLee YK, Choi KW, Woo SH, Ho PC, Lee (2018) The clinical result of arthroscopic bone grafting and percutaneous K-wires fixation for management of scaphoid nonunions. Medicine (Baltimore) 97(13):e9987.https://doi.org/10.1097/MD.0000000000009987\u003c/li\u003e\n \u003cli\u003eKang HJ, Chun YM, Koh IH, Park JH, Choi YR (2016) Is Arthroscopic Bone Graft and Fixation for Scaphoid Nonunions Effective? Clin Orthop Relat Res 474(1):204-212.https://doi.org/10.1007/s11999-015-4495-3\u003c/li\u003e\n \u003cli\u003eCognet JM, Louis P, Martinache X, Schernberg F (2017) Arthroscopic grafting of scaphoid nonunion - surgical technique and preliminary findings from 23 cases. Hand Surg Rehabil. 36(1):17-23.https://doi.org/10.1016/j.hansur.2016.11.002\u003c/li\u003e\n \u003cli\u003eMerrell GA, Wolfe SW, Slade JF 3rd (2002) Treatment of scaphoid nonunions: quantitative meta-analysis of the literature. J Hand Surg Am 27(4):685-691.https://doi.org/10.1053/jhsu.2002.34372\u003c/li\u003e\n \u003cli\u003eEcker J, Shahbaz L, Kohli S, Breidahl W, Andrijich C (2022) Arthroscopic Bone Graft and Internal Fixation of Non-Union of the Proximal Pole of the Scaphoid: Surgical Technique and Outcomes. J Wrist Surg 20;11(6):535-540.https://doi.org/10.1055/s-0041-1742097\u003c/li\u003e\n \u003cli\u003eIllarramendi AA, Schulz C, De Carli P (2001) The surgical treatment of Kienb\u0026ouml;ck\u0026apos;s disease by radius and ulna metaphyseal core decompression. J Hand Surg Am 26(2):252-260.https://doi.org/10.1053/jhsu.2001.22928\u003c/li\u003e\n \u003cli\u003eTambe AD, Cutler L, Murali SR, Trail IA, Stanley JK (2006) In scaphoid non-union, does the source of graft affect outcome? Iliac crest versus distal end of radius bone graft. J Hand Surg Br 31(1):47-51.https://doi.org/10.1016/j.jhsb.2005.07.008\u003c/li\u003e\n \u003cli\u003eSchmidle G, Ebner HL, Klima G, Pfaller K, Fritz J, Hoermann R, Gabl M (2018) Time-dependent changes in bone healing capacity of scaphoid fractures and non-unions. J Anat 232(6):908-918.https://doi.org/10.1111/joa.12795\u003c/li\u003e\n \u003cli\u003eRancy SK, Swanstrom MM, DiCarlo EF, Sneag DB, Lee SK, Wolfe SW; Scaphoid Nonunion Consortium (2018) Success of scaphoid nonunion surgery is independent of proximal pole vascularity. J Hand Surg Eur Vol 43(1):32-40.https://doi.org/10.1177/1753193417732003\u003c/li\u003e\n \u003cli\u003eLin TY, Fu CW, Tsai PS, Huang CH, Wei SH, Chuang MY (2023) Outcomes after arthroscopic treatment for scaphoid nonunion using ipsilateral radius bone graft and a headless compression screw: a comparison between the patients with and without avascular necrosis. Int Orthop 47(4):1041-1049.https://doi.org/10.1007/s00264-023-05700-5\u003c/li\u003e\n \u003cli\u003eZemirline A, Lebailly F, Taleb C, Naito K (2019) Arthroscopic treatment of scaphoid nonunion with humpback deformity and DISI with corticocancellous bone grafting: Technical note. Hand Surg Rehabil 38(5):280-285.https://doi.org/10.1016/j.hansur.2019.07.007\u003c/li\u003e\n \u003cli\u003eOh WT, Kang HJ, Chun YM, Koh IH, Lee YJ, Choi YR (2018) Retrospective Comparative Outcomes Analysis of Arthroscopic VersusOpen Bone Graft and Fixation for Unstable Scaphoid Nonunions. Arthroscopy 34(10):2810-2818.https://doi.org/10.1016/j.arthro.2018.04.024\u003c/li\u003e\n \u003cli\u003eGvozdenovic R, Kongensgaard TB (2023) Results of arthroscopic cancellous bone grafting for treatment of scaphoid nonunion in comparison with open cancellous bone grafting. J Hand Surg Eur Vol 48(9):903-910.https://doi.org/10.1177/17531934231166343\u003c/li\u003e\n \u003cli\u003eKjaer M, Rasmussen JV, Gvozdenovic R (2023) Arthroscopic versus open cancellous bone grafting for scaphoid delayed/nonunion in adults (SCOPE-OUT): study protocol for a randomized clinical trial. Trials 14;24(1):273.https://doi.org/10.1186/s13063-023-07281-5\u003c/li\u003e\n \u003cli\u003eShih YC, Wu CC, Shih JT (2023) Arthroscopic treatment of stable nonunion, unstable nonunion, or nonunionof the scaphoid with early degenerative radioscaphoid arthritis. J Orthop Surg Res 21;18(1):123.https://doi.org/10.1186/s13018-023-03609-8\u003c/li\u003e\n \u003cli\u003eWang JP, Huang HK, Shih JT (2020) Arthroscopic-assisted reduction, bone grafting and screw fixation across the scapholunate joint for proximal pole scaphoid nonunion. BMC Musculoskelet Disord 10;21(1):834.https://doi.org/10.1186/s12891-020-03850-w\u003c/li\u003e\n \u003cli\u003eCheng C, Jiang Z, Sun H, Hu J, Ouyang Y (2023) Arthroscopic treatment of unstable scaphoid fracture and nonunion with two headless compression screws and distal radius bone graft. J Orthop Surg Res 18;18(1):52.https://doi.org/10.1186/s13018-023-03529-7\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1, Demographic data of patients\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eAge (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e21.3 (16-38)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eDuration of SNU (months)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e18.6 (6-120)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eDuration of pain (months)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e8.8 (2-48)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eSex Female/Male\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e3/49\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eRhight/left hand\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e30/22\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eSNU Scaphoid Non Union\u003c/p\u003e\n\u003cp\u003eTable 2, Schmidle classification\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003eCT-Classification\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003eI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003eII\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003eIII\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e31 (59.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e19 (36.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e2 (3.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eSchmidle et al. [14]\u003c/p\u003e\n\u003cp\u003eTable 3, Level of \u0026nbsp;Scaphoid nonunion\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003eLevel of non union\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e2017-2020\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e2020-2023\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003etotal\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003eDistal 1/3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003eWaist\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e18 (34.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e16 (30.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e34 (65.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003eProximal 1/3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e4 (7.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e14 (26.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 151px;\"\u003e\n \u003cp\u003e18 (34.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 4, Outcome after arthroscopic treatment of Scaphoid nonunion\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eOutcome evaluation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003ePre-operative mean (min/max)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eFollow-up mean (min/max)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eVAS pain score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e2.7 (1.2/5.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e0.7 (0/3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eDASH Score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e32 (0.5/68.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e5.4 (0.5/35)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eMMWS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e47.4 (20/90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e94.9 (60/100)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eS-L angle\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e54.9\u0026deg; (41\u0026deg;/75\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e54.1\u0026deg; (45\u0026deg;/67\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eR-L angle\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e14.3\u0026deg; (5\u0026deg;/36\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e13.2\u0026deg; (5\u0026deg;/30\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eIntrascaphoid angle\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e49\u0026deg; (25\u0026deg;-77\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e45\u0026deg; (20\u0026deg;-70\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eVAS visual analogue scale, MMWS Modified Mayo Wrist Score\u003c/p\u003e\n\u003cp\u003eTable 4, Outcome after arthroscopic treatment of Scaphoid nonunion\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eOutcome evaluation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003ePre-operative mean (min/max)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eFollow-up mean (min/max)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eVAS pain score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e2.7 (1.2/5.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e0.7 (0/3)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eDASH Score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e32 (0.5/68.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e5.4 (0.5/35)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eMMWS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e47.4 (20/90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e94.9 (60/100)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eS-L angle\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e54.9\u0026deg; (41\u0026deg;/75\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e54.1\u0026deg; (45\u0026deg;/67\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eR-L angle\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e14.3\u0026deg; (5\u0026deg;/36\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e13.2\u0026deg; (5\u0026deg;/30\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003eIntrascaphoid angle\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e49\u0026deg; (25\u0026deg;-77\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 201px;\"\u003e\n \u003cp\u003e45\u0026deg; (20\u0026deg;-70\u0026deg;)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eVAS visual analogue scale, MMWS Modified Mayo Wrist Score\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"archives-of-orthopaedic-and-trauma-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"aots","sideBox":"Learn more about [Archives of Orthopaedic and Trauma Surgery](http://link.springer.com/journal/402)","snPcode":"402","submissionUrl":"https://submission.springernature.com/new-submission/402/3","title":"Archives of Orthopaedic and Trauma Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Scaphoid nonunion, wrist arthroscopy, radius bone graft, extra corporal shockwave, wrist injuries, internal fixation","lastPublishedDoi":"10.21203/rs.3.rs-5697154/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5697154/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eIntroduction:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eScaphoid nonunion is still a challenging problem in hand surgery. Till now most of the patients have been treated with open revision, bone grafting and internal stabilization.\u003c/p\u003e\n\u003cp\u003eArthroscopy plays an increasing role in hand surgery since the last decade. Three years after starting the use of arthroscopic treatment of scaphoid nonunion we analyzed our results and modified our therapy protocol.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterial and Methods:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn 2017, we started arthroscopic treatment of scaphoid nonunion at our department. Debridement is done arthroscopically as well as insertion of radius cancellous bone graft. Fixation has been accomplished with K-wires and/or head compression screws percutaneously, by help of x-ray.\u003c/p\u003e\n\u003cp\u003eTill 2020, we treated 24 patients, observing three delayed unions, treated successfully by extra corporal shockwave therapy and modifying the fixation.\u003c/p\u003e\n\u003cp\u003eAnalyzing these results, we modified our fixation methods and all patients, got shockwave therapy additionally.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e:\u003c/p\u003e\n\u003cp\u003eComparing the success rate with the 28 operated after 2020, the adaption of our algorithm showed an improvement of our results concerning healing rate. There we found only one ongoing nonunion in the proximal 1/3. The median time to healing was comparable in the two groups, operation time showed no significant difference.\u003c/p\u003e\n\u003cp\u003eAfter a median follow-up of 30 months, we found an excellent range of motion, a significant reduction in pain and grip strength matchable with the unaffected hand in all 52 patients. DASH and Mayo Wrist Score showed satisfactory results, and 45 patients came back to their earlier occupation and sports.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e:\u003c/p\u003e\n\u003cp\u003eArthroscopy has a fix place in the algorithm for scaphoid nonunion in our institution. We think an adequate and stabile fixation adopted to the section of the nonunion is indispensable.\u003c/p\u003e\n\u003cp\u003eThe distal radius is a sufficient donor-site for cancellous bone grafting.\u003c/p\u003e\n\u003cp\u003eExtra corporal shockwave therapy should be used routinely in scaphoid nonunion.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLevel of evidence:\u003c/strong\u003e IV\u003c/p\u003e","manuscriptTitle":"Arthroscopic treatment of scaphoid nonunion, a new algorithm after six years practice","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-01-01 09:23:00","doi":"10.21203/rs.3.rs-5697154/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-01-10T14:22:05+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-01-07T21:10:58+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"109973863497204856485502665161863105588","date":"2025-01-01T21:01:58+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-12-31T16:54:24+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"292880553382108782241552253008113571347","date":"2024-12-31T09:44:04+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-12-30T18:25:06+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-12-30T13:59:26+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-12-30T13:58:31+00:00","index":"","fulltext":""},{"type":"submitted","content":"Archives of Orthopaedic and Trauma Surgery","date":"2024-12-23T06:50:23+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"archives-of-orthopaedic-and-trauma-surgery","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"aots","sideBox":"Learn more about [Archives of Orthopaedic and Trauma Surgery](http://link.springer.com/journal/402)","snPcode":"402","submissionUrl":"https://submission.springernature.com/new-submission/402/3","title":"Archives of Orthopaedic and Trauma Surgery","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"ef6b24e7-62fe-4a02-8fd8-686db3bc2dd4","owner":[],"postedDate":"January 1st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-02-24T15:58:19+00:00","versionOfRecord":{"articleIdentity":"rs-5697154","link":"https://doi.org/10.1007/s00402-025-05777-0","journal":{"identity":"archives-of-orthopaedic-and-trauma-surgery","isVorOnly":false,"title":"Archives of Orthopaedic and Trauma Surgery"},"publishedOn":"2025-02-19 15:56:51","publishedOnDateReadable":"February 19th, 2025"},"versionCreatedAt":"2025-01-01 09:23:00","video":"","vorDoi":"10.1007/s00402-025-05777-0","vorDoiUrl":"https://doi.org/10.1007/s00402-025-05777-0","workflowStages":[]},"version":"v1","identity":"rs-5697154","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5697154","identity":"rs-5697154","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}