What is the recommended rehabilitation protocol after Medial Collateral Ligament (MCL) repair in Total Knee Replacement (TKR)?

Rehabilitation After MCL Repair in Total Knee Replacement

Begin immediate mobilization and isometric quadriceps exercises within the first postoperative week, prioritize closed kinetic chain exercises for the first 6-8 weeks to protect the MCL repair, and delay open kinetic chain exercises until at least 4 weeks with extreme caution given the combined ligament repair and arthroplasty. 1

Immediate Postoperative Phase (0-2 Weeks)

Start isometric quadriceps exercises immediately including static quadriceps contractions and straight leg raises during the first 2 postoperative weeks, which accelerates knee range of motion recovery at 1 month without compromising stability. 2, 1

• Initiate knee mobilization within the first week to improve range of motion and reduce pain without compromising the MCL repair. 1
• Progress weight-bearing as tolerated within the first week, though maintain a more conservative approach than isolated ACL reconstruction given the MCL repair. 1
• Apply cryotherapy immediately after surgery and throughout the first postoperative week to reduce knee pain and swelling. 2, 1, 3
• Consider neuromuscular electrical stimulation (NMES) for the initial 6-8 weeks as an adjunct to isometric strength training to re-educate voluntary quadriceps contraction. 1, 3
• Allow immediate weight bearing only if correct gait pattern is maintained (with crutches if necessary) and there is no pain, effusion, or temperature increase when walking. 2, 3

Moderate Protection Phase (2-6 Weeks)

Prioritize closed kinetic chain exercises (leg press, squats, step-ups) over open kinetic chain exercises to minimize stress on the MCL repair. 2, 1, 4

• Begin closed kinetic chain exercises from week 2 postoperative, emphasizing these exercises for the first 6-8 weeks to protect the healing ligament. 1, 3
• Start leg press at 3 weeks to improve subjective knee function and functional outcomes. 2, 1
• Progress from isometric exercises to concentric and eccentric exercises when the quadriceps is reactivated and the knee does not react with effusion or increased pain. 3
• Open kinetic chain exercises (90-45°) may be cautiously added as early as 4 weeks, but introduce with extreme caution given the MCL repair. 2, 1
• Avoid aggressive resistance with open kinetic chain exercises during this phase to protect the healing MCL. 1

Minimum Protection Phase (6-12 Weeks)

Advance to both open and closed kinetic chain exercises with progressive resistance, combining strength training with neuromuscular training to restore dynamic stability. 2, 1

• Use both open and closed kinetic chain exercises for regaining quadriceps strength, as there is no significant difference in anterior tibial laxity between the two approaches. 2
• Implement eccentric training components starting at 3 weeks (if not already initiated), which may result in greater strength gains, better daily activity level, and greater quadriceps muscle hypertrophy. 2, 1
• Progress from basic activities of daily living to more demanding functional tasks. 1
• Continue neuromuscular training alongside strength training to optimize self-reported outcomes and prevent reinjuries. 2, 3

Return to Function Phase (3-6 Months)

Base progression on objective criteria rather than time alone, requiring limb symmetry index >90% for strength testing before advancing to higher-level activities. 1, 4

• Ensure no pain, swelling, or instability on examination before progression. 1
• Perform isokinetic quadriceps and hamstring peak torque testing at 60°/s demonstrating 100% symmetry. 1
• Assess countermovement jump and drop jump with >90% symmetry. 1
• Evaluate patient-reported outcomes including IKDC subjective knee form and psychological readiness scales. 2, 1
• Continue rehabilitation for 9-12 months depending on the final return-to-work or play goals. 2, 3

Critical Pitfalls to Avoid

• Do not delay mobilization, as this leads to stiffness and extension deficits, but balance early motion with ligament protection. 1, 3
• Do not advance to aggressive open kinetic chain exercises before 4 weeks, and maintain a conservative approach throughout due to the MCL repair. 2, 1
• Do not use time-based progression alone; instead use criteria-based advancement to higher-level activities. 1, 4
• Do not neglect closed kinetic chain exercises in early phases, as these protect the healing ligament while building strength. 1, 4
• Do not fail to address quadriceps strength deficits, as preoperative deficits >20% significantly impact self-reported outcomes 2 years after surgery. 2, 3