Impact of a mobile-bearing total knee arthroplasty design on non-resurfaced patellar tracking | ||
| The Egyptian Orthopaedic Journal | ||
| Volume 48, Issue 2, June 2013, Pages 151-155 PDF (624.44 K) | ||
| DOI: 10.7123/01.EOJ.0000428876.38331.5a | ||
| Authors | ||
| Mohamed A.M. Eid; Tamer Fayad | ||
| Abstract | ||
| Background Unlike fixed-bearing total knee arthroplasty (TKA), mobile-bearing TKA is designed to accommodate for small mismatches in the rotational position of the femoral and tibial components owing to mobility of the bearing insert. Thereby, central patellar tracking is potentially facilitated. The aim of this study is to determine whether the incidence of lateral retinacular release would be lower in knees replaced with a mobile-bearing TKA as compared with a fixed-bearing TKA design. Patients and methods A standardized surgical technique was applied in 64 consecutive cases with advanced varus osteoarthritis. A single cruciate-substituting knee design was used in all patients. The selection of a fixed-bearing versus mobile-bearing TKA was made primarily on the basis of knee stability, age, and lifestyle activities. There were 39 women and 25 men in the study, mean age 64.5 years (range, 56–77 years). A mobile-bearing TKA design was implanted in half of the cases (32) and a fixed-bearing design was equally implanted in the other half. Results The overall lateral retinacular release rate in this study was 12.5% (eight of 64 knees). The incidence of lateral retinacular release was higher (<0.005) for knees replaced with a fixed-bearing tibial component (18.7%, six of 32 knees) than for knees replaced with a mobile-bearing tibial component (6.25%, two of 32 knees). The overall incidence of postoperative patellar tilt of 5° or more shown on Merchant follow-up radiographs of the patella was 14% (nine of 64 knees). The incidence of residual patellar tilt was slightly higher in the fixed-bearing group (15.6%, five of 32) than in the mobile-bearing group (12.5%, four of 32). In both the fixed-bearing group (=0.053) and the mobile-bearing group (=0.012), the amount of patellar tilt was higher in patients in whom a lateral retinacular release was not performed. No patient in either study group showed patellar subluxation of more than 5 mm on follow-up radiographs. Conclusion In conclusion, the current study showed that decreased incidence of lateral retinacular release could be one potential advantage of the mobile-bearing TKA design. However, further long-term follow-up studies are still required to document other theoretical benefits of mobile-bearing TKA with respect to reduced polyethylene wear, durable long-term fixation, and patellofemoral performance. | ||
| Keywords | ||
| fixed-bearing total knee arthroplasty; mobile-bearing total knee arthroplasty; total knee arthroplasty | ||
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