Objective:

To evaluate quadriceps and hamstring strength and flexibility changes following total knee arthroplasty over a 12-month period.

Approach:

• Study Design: A prospective, longitudinal single-center study involving patients aged 50 to 80 years with severe knee osteoarthritis scheduled for total knee arthroplasty.
• Participants: 77 patients were enrolled, with follow-up completed by 77 at 6 weeks and 3 months, 54 at 6 months, and 26 at 12 months.
• Assessment Methods: Quadriceps and hamstring strength were evaluated using handheld dynamometry, and flexibility was assessed through passive knee extension and a modified Thomas test.
• Rehabilitation Program: Patients underwent a standardized postoperative rehabilitation program including progressive strengthening, mobility, stretching, functional training, balance training, and aerobic conditioning.

Key Findings:

• Mean quadriceps strength decreased from 12 lbs preoperatively to 7 lbs at 6 weeks, then increased to 30 lbs at 3 months, 38 lbs at 6 months, and 43 lbs at 12 months.
• Mean hamstring strength decreased from 20 lbs preoperatively to 13 lbs at 6 weeks, then increased to 30 lbs at 3 months, 42 lbs at 6 months, and 58 lbs at 12 months.
• At 12 months, quadriceps and hamstring strength remained lower compared with control values of 75 lbs and 68 lbs, respectively.

Limitations:

• Attrition at 12 months may limit generalizability.
• Absence of blinded outcome assessment may introduce bias.
• Analysis did not account for postoperative pain, rehabilitation adherence, or physical activity.

Sources:

• Journal of Orthopaedics