What is the recommended rehabilitation plan for a patient undergoing Medial Collateral Ligament (MCL) repair during Total Knee Replacement (TKR)?

Rehabilitation After MCL Repair During Total Knee Replacement

For patients undergoing MCL repair during TKR, implement a conservative, phase-based rehabilitation protocol with hinged knee bracing for 6 weeks, prioritizing early mobilization and closed kinetic chain exercises while protecting the healing ligament, followed by progressive strengthening based on objective criteria rather than time alone. 1, 2

Immediate Postoperative Phase (0-2 Weeks)

The most critical intervention is applying an unlocked hinged knee brace for 6 weeks postoperatively to protect the MCL repair while allowing controlled motion. 2 This bracing protocol has been shown to successfully treat intraoperative MCL injuries without requiring increased prosthetic constraint, with no instability at long-term follow-up. 2

Early Mobilization and Exercise

• Initiate immediate knee mobilization within the first week to improve range of motion and reduce pain without compromising stability. 1 This early mobilization is critical to prevent stiffness, which is a common complication after MCL repair during TKR. 2
• Begin isometric quadriceps exercises (static quadriceps contractions and straight leg raises) during the first 2 weeks. 1, 3 These exercises can be safely prescribed and confer advantages for faster recovery of knee range of motion at 1 month without compromising stability. 1
• Progress weight-bearing as tolerated within the first week, though more conservatively than isolated ACL reconstruction given the MCL repair. 1 Early weight-bearing reduces patellofemoral pain without increasing laxity. 1

Adjunctive Modalities

• Apply cryotherapy immediately after surgery to reduce knee pain and swelling. 1, 3
• Consider neuromuscular electrostimulation (NMES) for the initial 6-8 weeks to re-educate voluntary quadriceps contraction. 1, 3

Moderate Protection Phase (2-6 Weeks)

This phase requires the most conservative approach due to the healing MCL repair, with strict prioritization of closed kinetic chain exercises. 1

Exercise Prescription

• Prioritize closed kinetic chain exercises (leg press, squats, step-ups) over open kinetic chain exercises to minimize stress on the MCL repair. 1, 3 Closed kinetic chain exercises should be emphasized in the first 6-8 weeks to protect the healing ligament. 1
• Begin leg press at 3 weeks to improve subjective knee function and functional outcomes. 1
• Open kinetic chain exercises (90-45°) may be cautiously added as early as 4 weeks, but should be introduced with extreme caution given the MCL repair. 1, 3 Avoid aggressive resistance with open kinetic chain exercises during this phase. 1
• Continue wearing the hinged knee brace throughout this entire phase. 2

Minimum Protection Phase (6-12 Weeks)

At 6 weeks, the hinged brace can be discontinued if there are no signs of instability, and rehabilitation can advance more aggressively. 2

Progressive Strengthening

• Advance to both open and closed kinetic chain exercises with progressive resistance. 1, 3
• Combine strength training with neuromuscular/motor control training to restore dynamic stability. 1, 4
• Implement eccentric training components, which may result in greater strength gains and quadriceps muscle hypertrophy. 1
• Progress from basic activities of daily living to more demanding functional tasks. 1

Return to Function Phase (3-6 Months)

Base progression on objective criteria rather than time alone, as functional recovery is unpredictable after TKR with MCL repair. 1, 4

Objective Discharge Criteria

• Achieve limb symmetry index >90% for strength testing before advancing to higher-level activities. 1, 4
• Ensure no pain, swelling, or instability on examination. 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. 1, 3

Critical Pitfalls to Avoid

Stiffness is the most common complication after MCL repair during TKR, occurring in approximately 11% of cases. 2 To minimize this risk:

• Do not delay early mobilization, as this leads to stiffness and extension deficits, but balance this with ligament protection through bracing. 1, 2
• Do not advance to aggressive open kinetic chain exercises before 4 weeks. 1, 3
• Maintain a conservative approach to open kinetic chain exercises throughout the first 6-8 weeks due to the presence of MCL repair. 1
• Do not remove the hinged brace before 6 weeks postoperatively. 2
• Use criteria-based rather than time-based progression to higher-level activities, as recovery is unpredictable. 1, 4
• Do not use continuous passive motion, as it is not recommended and may contribute to stiffness. 3

Special Considerations

The combination of TKR and MCL repair creates unique challenges compared to isolated procedures. 2 The need for ligament healing requires more conservative early rehabilitation than standard TKR, while the risk of stiffness from the arthroplasty demands aggressive mobilization. 2 This paradox is best managed through the hinged brace protocol, which allows early motion while protecting the repair. 2

Aseptic loosening occurred in 4% of cases at long-term follow-up, suggesting that proper rehabilitation and protection of the MCL repair does not compromise implant fixation. 2