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

Rehabilitation After MCL Injury and Repair in Total Knee Replacement

After MCL repair during TKR, implement immediate protected mobilization with a hinged knee brace for 6 weeks, early isometric quadriceps exercises from the first postoperative week, and prioritize closed kinetic chain exercises while avoiding aggressive open kinetic chain movements until at least 4 weeks. 1

Immediate Postoperative Phase (0-2 Weeks)

Bracing and Protection

• Use an unlocked hinged knee brace for 6 weeks postoperatively to protect the MCL repair while allowing controlled motion 1
• This approach has demonstrated successful outcomes without instability at long-term follow-up (mean 99 months) in patients with intraoperative MCL injuries during TKR 1

Early Mobilization

• Initiate immediate knee mobilization within the first week to improve range of motion and reduce pain without compromising stability 2
• Begin isometric quadriceps exercises including static quadriceps contractions and straight leg raises during the first 2 postoperative weeks 2, 3
• These exercises can be safely prescribed and confer advantages for faster recovery of knee range of motion at 1 month without compromising stability 2

Weight-Bearing

• Progress weight-bearing as tolerated within the first week, though this should be more conservative than isolated ACL reconstruction given the MCL repair 2
• The evidence supports early weight-bearing reduces patellofemoral pain without increasing laxity 2

Adjunctive Modalities

• Apply cryotherapy immediately after surgery to reduce knee pain and swelling 2, 3
• Consider neuromuscular electrostimulation (NMES) for the initial 6-8 weeks to re-educate voluntary quadriceps contraction 2

Moderate Protection Phase (2-6 Weeks)

Exercise Progression

• Prioritize closed kinetic chain exercises (leg press, squats, step-ups) over open kinetic chain exercises to minimize stress on the MCL repair 2, 3
• Closed kinetic chain exercises should be emphasized in the first 6-8 weeks to protect the healing ligament 3
• Begin leg press at 3 weeks to improve subjective knee function and functional outcomes 2

Range of Motion

• Progress to full range of motion as tolerated, avoiding forced manipulation 1
• Monitor closely for stiffness, which is a common complication (occurred in 10% of MCL repairs during TKR) 1

Open Kinetic Chain Introduction

• 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 2, 3
• Avoid aggressive resistance with open kinetic chain exercises during this phase 2

Minimum Protection Phase (6-12 Weeks)

Brace Weaning

• Discontinue hinged knee brace at 6 weeks if stability is maintained and healing is progressing appropriately 1

Progressive Strengthening

• Advance to both open and closed kinetic chain exercises with progressive resistance 2, 3
• Combine strength training with neuromuscular/motor control training to restore dynamic stability 2, 3
• Implement eccentric training components, which may result in greater strength gains and quadriceps muscle hypertrophy 2

Functional Activities

• Progress from basic activities of daily living to more demanding functional tasks 2
• Emphasize hamstring strengthening alongside quadriceps to maintain proper knee kinematics 4

Return to Function Phase (3-6 Months)

Criteria-Based Progression

• Base progression on objective criteria rather than time alone 2, 3
• Achieve limb symmetry index >90% for strength testing before advancing to higher-level activities 3
• Ensure no pain, swelling, or instability on examination 2

Functional Testing

• Perform isokinetic quadriceps and hamstring peak torque testing at 60°/s demonstrating 100% symmetry 2
• Assess countermovement jump and drop jump with >90% symmetry 2
• Evaluate patient-reported outcomes including IKDC subjective knee form and psychological readiness scales 2

Critical Pitfalls to Avoid

Stiffness Management

• Stiffness is the most common complication after MCL repair during TKR, occurring in approximately 10% of cases 1
• Early mobilization is critical to prevent this complication, but must be balanced with ligament protection 2
• If stiffness develops, manipulation under anesthesia may be required 1

Avoiding Premature Progression

• Do not advance to aggressive open kinetic chain exercises before 4 weeks 2, 3
• Maintain brace protection for the full 6-week period even if the patient feels stable 1
• Do not substitute functional milestones for adequate healing time in the early phases 4

Monitoring for Instability

• Regularly assess for valgus instability throughout rehabilitation 5
• If instability develops despite appropriate rehabilitation, revision to a constrained prosthesis may be necessary 5

Key Differences from Standard TKR Rehabilitation

The presence of MCL repair necessitates:

• Extended bracing period (6 weeks vs. none in standard TKR) 1
• More conservative approach to open kinetic chain exercises 3
• Greater emphasis on closed kinetic chain exercises in early phases 2, 3
• Heightened vigilance for stiffness as a complication 1
• Criteria-based rather than time-based progression to higher-level activities 2, 3