Treatment Options for a Dislodged Tibial ACL Anchor
Surgical revision is the recommended treatment for a dislodged tibial ACL anchor to prevent graft failure and restore knee stability, with rehabilitation following evidence-based protocols to optimize outcomes and reduce reinjury risk.
Immediate Management
When an ACL tibial anchor becomes dislodged, prompt assessment and intervention are necessary to prevent further complications:
- Pain management: Apply cryotherapy with compression to reduce pain and swelling 1
- Activity modification: Immediate restriction of weight-bearing and movement to prevent further displacement
- Imaging: Obtain standard knee X-rays to confirm anchor position and assess for any associated damage 1
Surgical Options
Primary Surgical Revision
The gold standard treatment for a dislodged tibial anchor is surgical revision to restore graft stability:
Bioabsorbable suture anchor fixation:
Post cortical screw fixation:
Revision with interference screw:
- May be considered but offers limited pullout strength when used alone 2
- Additional fixation methods are recommended for aggressive rehabilitation
Post-Revision Rehabilitation Protocol
Following surgical revision, a structured rehabilitation program is essential:
Phase 1: Maximum Protection (0-12 weeks)
- Week 1: Immediate knee mobilization, isometric quadriceps exercises if pain-free, cryotherapy 4, 1
- Weeks 1-4: Closed kinetic chain exercises should be prioritized to mitigate patellofemoral pain 4
- Week 4: Begin open kinetic chain exercises in restricted ROM (90-45°) 4
- Weeks 4-8: Gradually increase ROM according to schedule, progressing from 90-45° to full ROM 1
Phase 2: Progressive Strengthening (12-24 weeks)
- Add neuromuscular training to strength training 4, 1
- Eccentric cycle ergometer training may result in greater strength gains if initiated early 4
- Combination of eccentric and plyometric exercises is more effective in improving balance, functional activities, and subjective knee function 4
Phase 3: Return to Function (24-48 weeks)
- Continue rehabilitation for 9-12 months depending on return-to-activity goals 1
- Perform functional evaluation including hop tests before return to sport 1
- Aim for Limb Symmetry Index (LSI) >90% for strength and hop tests 1
Common Pitfalls and Considerations
Early weight bearing: While immediate weight bearing is recommended in standard ACL rehabilitation 4, caution should be exercised with dislodged anchors until proper fixation is achieved
Graft protection: Hamstring grafts might be more vulnerable to early introduction of open kinetic chain exercises compared to bone-patellar tendon-bone grafts 4
Rehabilitation progression: Avoid accelerating rehabilitation timelines after revision surgery, as biological healing of the graft requires adequate time regardless of fixation strength 4
Psychological factors: Evaluate psychological changes during rehabilitation, as factors like self-efficacy and fear of reinjury influence outcomes 1
Return to Activity Criteria
Return to activity should be based on functional criteria, not just time since surgery:
- No pain or swelling
- Full knee ROM
- Stable knee on examination
- Normalized subjective knee function and psychological readiness
- Limb symmetry index >90% for quadriceps strength 1
For return to sport/activity, aim for 100% symmetry in isokinetic quadriceps and hamstring peak torque at 60°/s and >90% symmetry in jump height and impulse measurements 1.
By following this comprehensive approach to managing a dislodged tibial ACL anchor, patients can achieve optimal outcomes with restored knee stability and function.