Comparison of clinical outcomes between cruciate-retaining and posterior-stabilized total knee arthroplasty in patients with mild to moderate patellofemoral joint osteoarthritis

Background The clinical results of a total knee arthroplasty (TKA) without patellar resurfacing for knee osteoarthritis have been reported; however, not regarding comparison patellofemoral joint (PFJ) clinical outcomes using different prosthesis types. The purpose of this study is to compare clinical and imaging outcomes in patients with mild to moderate PFJ between cruciate-retaining TKA and posterior-stabilized TKA without patellar resurfacing. Methods The clinical and imaging outcomes of PFJ were compared between 107 knees (CR group) with CR TKA and 109 knees (PS group) with PS TKA. Radiological evaluations included the hip-knee-ankle angle (HKA), femoral rotation angle (FRA), patellar tilt angle (PTA), Insall–Salvati ratio (ISR), and patellar facet angle. Clinical assessment included the occurrence of anterior knee pain (AKP), patellar crepitus (PC), range of motion (ROM), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Knee Society Score (KSS). Results The incidence of AKP in the PS group was higher compared to the CR group ( p = 0.028) with no significant differences in terms of the time to the presentation of PC ( P 0.05). ROM in PS TKA was better than CR TKA ( p 0.05). There was no significant difference in postoperative KSS, WOMAC, HKA, FRA, PTA and ISR ( P 0.05) between the two groups. Conclusions This study prompt that TKA without patellar resurfacing for the treatment of PFJ osteoarthritis can obtain excellent clinical and radiological early outcomes regardless of the different prosthesis types. CR and PS TKA can achieve similar clinical results. Postoperative AKP may be more common in PS TKA. Level of evidence Level III.