Perceived Leg-Length Discrepancy After Primary Total Knee Arthroplasty: Does Knee Alignment Play a Role?

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Patient-Reported Outcomes

Background:

• Leg length discrepancy (LLD) is a known complication following total knee arthroplasty (TKA), yet its precise incidence and patient perception are not well-documented.
• Understanding patient-perceived LLD and its relationship with objective measures like knee alignment is crucial for improving TKA outcomes.

Purpose of the Study:

• To determine the incidence of perceived LLD before and after primary TKA.
• To investigate the correlation between the mechanical axis of the knee and perceived LLD.
• To assess the time frame for resolution of postoperative LLD.

Main Methods:

• Prospective enrollment of 73 patients undergoing primary TKA.
• Patient surveys assessing perceived LLD at multiple postoperative time points (3-6 weeks, 3, 6, and 12 months).
• Measurement of mechanical axis radiographs to correlate with perceived LLD, including analysis of varus and valgus deformities.

Main Results:

• Preoperatively, 18 out of 73 patients perceived LLD; postoperatively, only 7 patients perceived LLD.
• A significant decrease in perceived LLD was observed after TKA (P = .035).
• All 7 patients with postoperative LLD reported resolution within an average of 8.5 weeks; no significant correlation was found between knee alignment and perceived LLD.

Conclusions:

• Perceived leg length discrepancy is a common issue for patients undergoing total knee arthroplasty.
• TKA surgery generally leads to a reduction in perceived LLD, with most cases resolving within three months.
• Objective knee alignment does not appear to be a significant predictor of perceived LLD in TKA patients.