Comparisons among three approaches—two minimally invasive and one conventional—for total knee arthroplasty: a retrospective cohort study with minimum follow-up of 10 years

Background: Few studies have investigated whether the mini-medial parapatellar (MMP) and quadriceps-sparing (QS) approaches have good long-term results compared to the conventional medial parapatellar (MP) approach in terms of clinical evaluations and radiographic assessments for total knee arthroplasty (TKA). The purpose of this study was to perform comparisons among the MMP, QS and MP approaches with a follow-up at 10 to 17 years. Methods: This is a retrospective comparative study of 93 patients who underwent MMP TKA (32 TKAs), QS TKA (47 TKAs) or MP TKA (31 TKAs) with the same arthroplasty system. The clinical evaluations were performed according to the new American Knee Society score (KSS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the visual analogue scale (VAS), range of motion (ROM), incidence of anterior knee pain (AKP), the Feller patellofemoral score (PFS), the reoperation rate and the complication rates. Radiographic assessments included observation of the mechanical axis of the lower limb and calculations of the lateral distal femoral angle (LDFA), femoral flexion angle (FFA), medial proximal tibial angle (MPTA), tibial slope angle (TSA), lateral patella displacement (LPD), and lateral patella tilt (LPT). Results: There were no differences in the long-term follow-up results of the new KSS, WOMAC score, ROM, VAS, patellofemoral functions, reoperation rate or complication rates among the groups. In addition, no radiographic differences in terms of lower limb mechanical axis or femoral, tibial or patellar position were observed. Conclusion: These results provide conclusive evidence that equivalent, long-term clinical results can be obtained using any one of these three approaches.