Total knee arthroplasty using a pie-crusting technique for valgus deformity.

UNLABELLED: Valgus deformity correction with total knee arthroplasty is challenging. We hypothesized selective release of the tight lateral structures (pie-crusting technique), and of the lateral retinaculum in case of patellar maltracking, would obtain and maintain correction of the frontal plane deformity, restore patellar tracking and function, and avoid the complications of the extensive releases, including lateral condyle avascularity and residual lateral instability. We followed 48 patients with 53 valgus knees who underwent TKA and were followed a minimum of 5 years (mean, 8 years; range, 5-12 years). Soft tissue balancing of the lateral structures was performed with the pie-crusting technique. We employed either a fixed posterior stabilized or a mobile implant. A lateral release was performed in 67% of the cases. We observed one postoperative complication, a transient postoperative peroneal nerve palsy that spontaneously completely recovered. In 51 of the 53 knees (96%) we achieved alignment within 5 degrees from neutral. One patient had varus instability in extension. No component was revised. The pie-crusting technique reliably corrects moderate to severe fixed valgus deformities with a low complication rate and reasonable mid-term results. The multiple punctures allow gradual stretching of the lateral soft tissues and preservation of the popliteus tendon reducing the risk of posterolateral instability. LEVEL OF EVIDENCE: Level IV, case series. See the Guidelines for Authors for a complete description of levels of evidence.

Comparison of mobile-bearing and fixed-bearing total knee arthroplasty: a prospective randomized study.

The purpose of this prospective randomized study was to compare the postoperative recovery and early results of 2 groups of patients undergoing total knee arthroplasty: 107 patients received an established fixed-bearing posterior-stabilized prosthesis (Legacy Posterior Stabilized [LPS]), and 103 patients the meniscal-bearing prosthesis (Meniscal Bearing Knee [MBK]). Surgical procedures were the same for both groups except for posterior cruciate ligament management, which was sacrificed in the LPS group and spared but completely released from the tibia in the MBK group. At an average follow-up of 36 months, knee, function, and patellar scores were comparable in both groups. The LPS group showed a significantly higher maximum flexion than the MBK group (112 degrees vs 108 degrees). Using a fixed-bearing or a mobile-bearing design did not seem to influence the short-term recovery and early results after knee arthroplasty. Key words: total knee arthroplasty, mobile bearing, knee prosthesis, meniscal-bearing knee, posterior stabilized, prospective randomized.