RESUMO
Background: Malrotation of the tibial component in a total knee replacement leads to anterior knee pain, patella dislocations, extensor mechanism disruptions, knee stiffness and prosthesis loosening. Techniques like free-floating technique, medial 1/3 rd of the tibial tubercle, medial border of the tibial tuberosity, Akagi's line, transcondylar line of tibia, posterior condylar line of tibia, midsulcus of tibial spines, curve on curve technique have been advocated. None of these have been shown to be accurate and reproducible. We developed a novel 'Sharma's Venn Diagram' method to assess the tibial component rotation. Methods: Fifty-two consecutive knee replacements were included in a prospective observational study. The average age of the study group was 53.6 years (48-76 years) Thirty-one were females and 3 were males. The patients were followed a minimum of one years (max 2 years, average 1.8 years). 'Sharma's Venn diagram Method (C)' was compared to free-floating method (F) and post-op CT scans using Berger protocol (B). Results: Tibial rotation calculated using Sharma's Venn diagram method (C) coincided with the final component placement in 50/52 knees. The free floating method (F) coincided with method (C) in 30/52 knees with an average 4.8° external rotation in 5 knees and an average of 5.2° internal rotation in 17 knees. Bland Altman method was used to compare method (C) with Method (F), The difference was statistically significant p < 0.0001. Conclusion: Sharma's Venn diagram method is reliable, accurate and easily reproducible by any surgeon performing tkr and correlates with postoperative 2D CT-based assessment of tibial component rotation. Level II Study: Prospective observational study.
RESUMO
INTRODUCTION: Stiff knees are defined as those with an arc of motion < 50°. They pose a considerable surgical challenge to the operating surgeon. Based on our experience to deal with these complex cases, we have developed a working classification that outlines a flowchart to manage the stiff/ankylosed knees. MATERIALS AND METHODS: It was a retrospective study conducted in our department. Out of 570 TKA performed in last 5 years, 57 had stiffness and four had bony ankyloses (total 61 knees). Patients were classified based on the fibrous or bony ankylosis and preoperative ROM. RESULTS: Patients were followed for an average 2.4 years (1.8-5.5 years). KSS pain scores improved from an av. 32 preop (18-64) to av. 76 postoperatively (61-90). The KSS function scores improved from a preoperative value of 36 (16-56) to an av. 78 (52-90) postoperatively. ROM improved from an average of 35.6° (0°-44°) preoperatively to an average of 95.6° (ROM 73°-118°) postoperatively. Extension lag was an av. 8° (3°-12°) and was seen in 13 patients postoperatively. Residual fixed flexion deformity was an av. 7° (3°-14°) and seen in 17 patients. The stiff knees (type 1 and type 2) fared better than ankylosed knees (type 3) in all aspects. Complication rate was high (24%) in our series. CONCLUSION: Our classification of stiff/ankylosed knees guides the surgeon to decide upon which approach to take, which implants to keep handy and has a predictive and prognostic value.
