Comparison of computer-navigated and conventional total knee arthroplasty in patients with Ranawat type-II valgus deformity: Medium-Term clinical and radiological results

Background: Arthritic knees with Ranawat type-II valgus deformity present with soft tissue contracture and osseou anomalies that make total knee arthroplasty (TKA) difficult. We hypothesized that computer-navigated-TKA (CN-TKA may be superior to conventional techniques and provide better mid-Term radiographic and clinical outcomes i such cases Methods: Between January 2002 and January 2009, patients with Ranawat type-II valgus deformity who underwen primary TKA were entered into this retrospective study. Conventional TKA and CN-TKA were compared for th accuracy of component placement, joint line level, and postoperative limb alignment. International Knee Societ scores and patellar scores were used for clinical assessment Results: A total of 62 patients (70 knees) with a minimum of 5 years of follow-up were studied. Conventional TK was performed in 36 knees and CN-TKA in 34 knees. A significantly higher rate of lateral retinaculum release wa recorded in the conventional TKA group compared to the CN-TKA group. Proper restoration of joint line was achieve using CN-TKA. The range of motion of the knees was similar in both groups preoperative and postoperatively. Ther were no significant differences in reconstructed mechanical axes, accuracy of component positioning, and difference i perioperative hemoglobin level between the two groups. At a mean follow-up of 6.2 years, both groups had significan postoperative improvements in clinical performance, however the difference did not reach statistical significanc between both techniques Conclusions: Our findings demonstrate that CN-TKA can properly restored the joint line level for arthritic knee with Ranawat type II valgus deformity. However, no differences in clinical function, limb and component alignment, o survival of the prostheses were noted between the CN-TKA and conventional TKA groups at a mean follow-up o 6.2 years.