Good Operative Effects of Patellofemoral Arthroplasty Combined With the Tibial Tubercle Transfer for Isolated Patellofemoral Arthritis Patients With an Increased Tibial Tuberosity-trochlear Groove Distance

Purpose: The objective of present study was to investigate the operative effect of patellofemoral arthroplasty combined with the tibial tubercle transfer for isolated patellofemoral arthritis patients with an increased tibial tuberosity-trochlear groove distance (>20mm). Methods: : A prospective study was performed between November 2012 and December 2017. Finally, thirty-six cases, with a mean age of 61.1 ± 7.3 years, were admitted to our study. A total of 17 patients underwent patellofemoral arthroplasty combined with tibial tubercle transfer, and 19 patients underwent patellofemoral arthroplasty only. All eligible patients had CT scans preoperatively and at 12 months follow-up, to assess the stability of the patellofemoral joint on axial slices. In addition, the demographic and clinical features of all the patients were asked. Knee balance was assessed with the single leg stance test and timed get up and go, and functionality was evaluated with stair climbing test and the Western Ontario and McMaster Universities Osteoarthritis Index score. (P>0.05) Results: : Preoperatively, the data regarding the knee balance and functionality were not significantly different between the two Groups (P>0.05). Many measurements showed significant differences between the two groups at the last follow-up. Significant differences were seen in well-known measurements such as the SLST (Group I, 28.9 s (SD 7.5); Group II, 20.3 s (SD 5.9); p < 0.001), TGUG (Group I, 13.4 s (SD 3.2); Group II, 16.8 s (SD 3.1); p < 0.001), and SCT (Group I, 18.6 s (SD 6.8); Group II, 24.5 s (SD 8.7); p < 0.001). Additionally, the median WOMAC score was improved from 62.7 (SD 11.2) preoperatively to 25.7 (SD 8.2) one year postoperatively in Group I and from 64.1 (SD 10.7) to 36.2 (SD 9.7) in Group II, which were also significantly different between the groups. Conclusion: For such special IPA patients with an increased TT-TG (>20mm), the combined operation of PFA combined with TTT can better restore the involutional relationship of patellofemoral joint and further improve the balance and function of knee joint.