Limb length discrepancy after total knee arthroplasty may contribute to suboptimal functional results

Purpose Limb length discrepancy (LLD) has been related to inferior outcomes after total hip arthroplasty (THA), but few studies have dealt with the LLD in primary total knee arthroplasty (TKA). The aims of the study were to examine the incidence of LLD after TKA and how it can influence in the outcomes scores. Methods We analysed preoperative, postoperative and changes in LLD in 460 patients who underwent a unilateral primary TKA. The measurements were done on digital full leg radiographs preoperatively and 6 months after surgery. The hip–knee–ankle (HKA) angle was also measured on these radiographs. Patients were evaluated with the Knee Society Score (KSS) preoperatively and 12 months after surgery. Results The average LLD was 1.1 mm in the preoperative period and changed to −0.8 mm in the postoperative (the 1.9 mm lengthening of the operated limb was statistically significant ( p