What is the treatment for a rupture of the distal aspect of the medial collateral ligament (MCL)?

Treatment of Distal Medial Collateral Ligament (MCL) Rupture

Distal MCL ruptures require operative fixation with direct repair and suture augmentation, as these injuries have poor healing capacity and high risk of residual valgus instability when treated conservatively. 1, 2

Why Distal MCL Ruptures Are Different

• Distal tibial avulsion injuries of the MCL require surgical treatment, unlike proximal or midsubstance tears which can heal with conservative management 1, 2
• The distal attachment has significantly worse healing potential compared to proximal MCL injuries, which can develop a "Stener-like lesion" where MCL fibers sublux superficial to the pes anserinus, preventing anatomic healing 3
• Nonoperative treatment of distal MCL ruptures results in inferior functional outcomes compared to proximal injuries, with lower IKDC2000 scores (median 62 vs 80) and Lysholm scores (median 75 vs 88) 1

Surgical Technique

The optimal fixation method is direct anatomic repair with suture augmentation using spiked PEEK washers secured with No. 2 polyester sutures (FiberWire), which provides superior biomechanical properties 4, 2:

• This technique yields the lowest elongation during cyclic loading (2.9 ± 0.7 mm) and highest ultimate failure load (469.8 ± 64.3 N) 4
• Alternative fixation includes 4.0-mm cancellous screws with washers or 5.5-mm titanium suture anchors, though these show inferior biomechanical performance 4
• The repair must restore anatomic insertion sites on the tibia to prevent residual valgus laxity 3, 2

Timing of Surgery

Acute surgical treatment (within 2-3 weeks) is preferred over delayed reconstruction 3, 5:

• Early surgery allows simultaneous treatment of concomitant ACL injuries if present, avoiding the traditional 6-week delay 5
• Delayed treatment prolongs overall rehabilitation, increases muscle atrophy, and leaves the knee unstable longer with risk of further intra-articular damage 5
• Acute repair prevents incomplete MCL healing that places ACL grafts at higher failure risk 5

Postoperative Protocol

Structured rehabilitation with protected range of motion is essential 3:

• Weeks 1-3: Brace locked at 0-20-60° (extension/flexion), partial weight bearing 10-20 kg 3
• Weeks 4-6: Brace adjusted to 0-10-90°, continue protected weight bearing 3
• After week 7: Free range of motion, progressive weight bearing 3
• If combined with PCL reconstruction, use 6 weeks immobilization in extension with posterior support, exercises only in prone position 3

Critical Pitfalls to Avoid

• Do not treat distal MCL avulsions conservatively—this is the one MCL injury pattern that consistently requires surgery 1, 2
• Avoid the outdated approach of delaying all MCL surgery for 6 weeks, which was based on historical concerns about postoperative stiffness from non-anatomic repairs 5
• Monitor for arthrofibrosis, which occurred in 3 of 34 cases (8.8%) in one surgical series, requiring revision 3
• Ensure valgus stress protection for full 6 weeks—premature loading risks repair failure 3

Concomitant Injuries

When combined with ACL or PCL injuries, perform simultaneous ligament reconstruction at the time of MCL repair 1, 3, 5:

• In multiligamentous knee injuries (KDIIIM pattern), early bicruciate reconstruction with MCL repair yields acceptable outcomes 1
• Combined procedures require more restrictive postoperative protocols, particularly with PCL involvement 3