Quadriceps angle as an outcome measure for structural integrity following total knee arthroplasty in individuals with severe knee osteoarthritis

Purpose: Total knee arthroplasty (TKA) is routinely performed for pain relief and to improve performance of the knee in individuals with severe knee osteoarthritis (OA). The quadriceps angle (Q-angle) is a key component of knee joint stability. However, there is a dearth of literature evaluating Q-angle as an outcome measure after TKA in individuals with severe knee OA.

Objectives: The objective of the study was to assess the Q-angle as an outcome measure before and after TKA and to find the correlation of Q-angle with pain, quadriceps strength, and knee flexion range of motion (ROM) after TKA in individuals with severe knee OA.

Methods: The Q-angles of 34 individuals (male: female = 17:17) were measured using standardized procedures. Pain, quadriceps strength, and knee flexion ROM were measured. The measurements were taken preoperatively (one day before surgery), and postoperatively at the sixth week and third month after TKA.

Results: The mean Q-angle was 19.17° (SD = 1.92°) before TKA, 16.06° (SD = 1.87°) at the sixth week and 13.43° (SD = 1.77°) at the third month after TKA. Significant linear correlations were noted between the Q-angle and pain, quadriceps strength, and knee flexion ROM following TKA.

Conclusion: The Q-angle was measured before and after TKA using a standardized clinical goniometric method. Understanding the Q-angle before and after TKA and its relationship with various clinical and functional variables is imperative in clinical practice for orthopedic surgeons and rehabilitation professionals.