Optimal intraoperative medial joint gap in extension to prevent flexion contracture following total knee arthroplasty using modified gap balancing technique.

Background: Primary aim to identify the ideal medial joint gap in extension needed to prevent post-operative flexion contracture following total knee arthroplasty (TKA) in varus osteoarthritic knees by the modified gap balancing technique. A secondary aim was to analyze multiple factors that influence knee extension in TKA by modified gap balancing. Methods: This is a prospective cohort study of 150 patients diagnosed with osteoarthritic varus knee who underwent TKA using the modified gap balancing technique. Operative and clinical records were assessed to determine factors including age, BMI (Body mass index), pre-operative extension angle and the medial extension laxity. Patients were followed for 6-months post-operatively and reviewed for knee extension angle. Results: Six months final follow-up information was available for 148 patients with an average age of 75.5 years. Pre-operative knee extension and BMI were significantly associated with post-operative knee extension. Post-operative flexion contracture of ≧ 100 was not seen in any of 34 patients with a medial extension laxity ≧ 0 mm who had no pre-existing flexion contracture, and in 1/9 (11.1%) patients with a medial extension laxity ≧ 1 mm who had pre-existing flexion contracture. Conclusions: Pre-operative extension angle and BMI significantly influence the post-operative knee extension angle in TKA using the modified gap balancing technique. A medial extension laxity of at least 1 mm is ideally needed to prevent post-operative flexion contracture in patients with a pre-existing contracture ≧ 100. Level of evidence: Level II; Prospective cohort study.

Resurfacing Egg-shell Patellar Defect in a Single-staged Primary total Knee Arthroplasty - A Case Report.

Introduction: Patellofemoral biomechanics are a very critical factor for patient satisfaction after total knee arthroplasty. Patellar defects in a primary total knee arthroplasty are rare. We present a rare case of valgus deformed knee with an eroded egg-shell like patella managed with primary knee arthroplasty. Case Report: A 58-year-old female with bilateral knee pain for 35-years presented to us with a bilateral valgus knee. The knee range of movement was restricted more on the left side and severely restricting her activities of daily living. She had an egg-shell like eroded patellar defect in an osteoarthritic knee for which, she underwent primary total knee arthroplasty and patellar resurfacing with autologous bone graft harvested from the tibial cut bone. Conclusion: We have presented a rare case of a combination of patellar defect in an Osteoarthritic knee which was managed by modified gapbalancing technique of TKA with a novel method of patellar resurfacing in a single stage with good functional results at 1-year postoperatively. This case improves our understanding of the management of such complex scenarios and, more importantly raises the questions our understanding and need of classification of such patellar defects in a primary arthritic knee.