Rehabilitation Protocol for PCL Avulsion Fracture Fixed with Cannulated Compression Screw
Overview
For PCL avulsion fractures fixed with cannulated compression screws, implement immediate controlled range of motion (40-70°) with progressive flexion advancement and early quadriceps strengthening, avoiding cast immobilization to optimize functional outcomes. 1
The rehabilitation approach for PCL avulsion fractures differs fundamentally from ACL reconstruction protocols due to the bony healing requirements and the PCL's unique biomechanical role in preventing posterior tibial translation. 2, 3
Phase 1: Maximum Protection (Weeks 0-6)
Immediate Postoperative Period (Week 0-2)
- Initiate immediate controlled range of motion (40-70°) in a functional brace rather than cast immobilization, as this approach yields superior outcomes compared to 4-6 weeks of casting. 1
- Apply cryotherapy for pain and swelling control during the first postoperative week. 4
- Begin isometric quadriceps exercises immediately on postoperative day one, as quadriceps strength is more critical than residual laxity for functional outcomes in PCL injuries. 2, 4
- Use neuromuscular electrical stimulation for quadriceps activation during the first 6-8 weeks to prevent atrophy while mechanical loading is restricted. 4
- Implement partial weight bearing of 10-20 kg with crutches to protect the fixation. 5
Weeks 2-6
- Progressively advance knee flexion restrictions:
- Continue partial weight bearing (10-20 kg) through week 4-6 to allow bony union. 5
- Prioritize closed kinetic chain exercises (leg press, mini-squats) over open kinetic chain exercises to minimize posterior tibial translation forces. 4
- Avoid posterior drawer stress and hamstring-dominant exercises that could displace the healing fragment. 2
Critical Pitfall: Unlike ACL reconstruction where immediate full weight bearing is safe, PCL avulsion fractures require protected weight bearing for 4-6 weeks to ensure bony union. 5
Phase 2: Moderate Protection (Weeks 6-12)
Weeks 6-8
- Advance to full weight bearing as tolerated once radiographic evidence of fracture union is confirmed. 3
- Progress knee flexion to full range of motion (typically 120-130°). 3
- Intensify quadriceps strengthening with progressive resistance, as quadriceps status determines functional outcome more than residual laxity. 2
- Begin stationary cycling once full weight bearing is achieved. 6
Weeks 8-12
- Initiate aquatic therapy once the surgical wound is fully healed (typically week 8-10). 6
- Add proprioceptive and balance training to improve functional outcomes. 6
- Continue combined strength and motor control training, as one cannot replace the other. 7, 4
- Assess for posterior sag sign and posterior drawer test to evaluate stability. 2
Key Consideration: Mild instability (1+ posterior drawer) may be present in some patients but is often consistent with functional stability if quadriceps strength is adequate. 3, 2
Phase 3: Minimum Protection (Weeks 12-24)
Months 3-6
- Progress to sport-specific exercises and functional training. 4
- Implement core stability exercises to improve gait mechanics. 6
- Add eccentric quadriceps exercises with progressive loading. 7
- Continue neuromuscular training combined with strength training throughout this phase. 4
- Avoid premature return to activities involving posterior tibial stress or hyperflexion. 2
Objective Progression Criteria
- Achieve limb symmetry index (LSI) >85% for quadriceps strength before advancing to plyometric training. 6
- Confirm full knee extension and flexion (average 121.7° ± 9.2°). 3
- Ensure no effusion, pain, or temperature increase with activities. 7
Phase 4: Return to Activity (Months 6-12)
Months 6-9
- Introduce plyometric and agility training cautiously once LSI >85% for strength and no valgus instability is confirmed. 6
- Implement sports-specific training programs with progressive exposure. 7, 4
- Address psychological factors, particularly fear of reinjury, which significantly impacts return to sport. 7
Return to Sport Criteria (Minimum 9 Months)
A minimum of 9-12 months is required before considering return to high-demand activities, significantly longer than isolated procedures. 6, 4
- Achieve LSI >90% for strength testing and functional hop tests. 6, 4
- For pivoting/contact sports, target LSI ≥100%. 4
- Confirm radiographic evidence of complete bony union. 3
- Document full range of motion with no more than mild instability (1+). 3
- Complete sports-specific training program with progressive controlled exposure. 7, 4
- Assess psychological readiness using validated instruments (ACL-RSI). 4
Critical Distinction: Return to sport clearance is not the same as return to competition; a transition phase from sports participation to sports performance is required. 7
Key Principles Throughout Rehabilitation
- Use criteria-based progression rather than time-based advancement, though minimum time requirements must be respected for bony healing. 4, 1
- Emphasize intensive quadriceps exercises throughout all phases, as muscular status determines outcome more than residual laxity. 2
- Avoid routine postoperative knee bracing beyond the initial functional brace period, as prolonged bracing impedes rehabilitation. 4
- Monitor for posterior sag sign and excessive posterior drawer as indicators of fixation failure. 2
- Set realistic goals and achieve well-defined milestones to maintain patient compliance through the extended rehabilitation period. 7
Expected Outcomes: With stable early fixation and aggressive rehabilitation, excellent to good results (Lysholm score 97 ± 7.6) can be achieved with fracture union in all cases. 3