Slope Reducing Osteotomy for Revision ACL Surgery
Introduction: Slope reducing osteotomy is an advanced surgical technique used alongside revision Anterior Cruciate Ligament (ACL) surgery to address excessive posterior tibial slope. An increased slope is often a primary factor in recurrent ACL graft failures. This sheet provides detailed information on the procedure, its mechanics, risks, and recovery expectations.
Understanding Posterior Tibial Slope and ACL Graft Failure:
- Posterior Tibial Slope: The angle of the tibial plateau, or slope, is crucial for knee stability. A slope greater than 12 degrees can cause excessive anterior tibial translation, putting undue strain on the ACL graft.
- Mechanics of Strain: A steeper slope allows the tibia to move forward more easily when the knee is under stress, increasing the likelihood of graft failure.
Slope Reducing Osteotomy Procedure:
- Indication: Recommended for patients with a posterior tibial slope above 12 degrees, aiming to reduce the slope to approximately 5 degrees (target range: 4-6 degrees).
- Technique Overview:
- Instruments and Imaging: The procedure uses standard surgical instruments and fluoroscopy for precision.
- Approach: The osteotomy is performed just above the patellar tendon attachment, using a closing wedge technique, which inherently provides stability.
- Incisions: Two longitudinal incisions are made on either side of the patellar tendon for access.
- Bone Cutting: Parallel K-wires are placed to guide the osteotomy. A microsagittal saw, chosen for its thin blade, makes the cut following the K-wire path, tapering medially and laterally.
- Bone Removal: The correction is estimated at approximately 1.5 degrees per millimeter of bone removed. For example, a 10-degree correction involves removing a 6-7mm bone wedge.
- Fixation: The osteotomy is stabilized with Arthrex staples one medial and two lateral.
Risks of the Procedure:
- Infection: As with any surgery, there is a risk of infection at the incision sites.
- Fracture: Cutting and repositioning the bone carries a risk of fracture.
- Neurovascular Injury: There is potential for damage to nearby nerves or blood vessels.
Outcomes and Recovery:
- Stability and Weight Bearing: The closing wedge technique ensures a stable osteotomy, allowing patients to bear weight immediately post-surgery.
- Range of Motion: Patients typically regain full range of motion early in the recovery process.
- Rehabilitation: A comprehensive rehabilitation program is essential for restoring strength and knee function.
- Long-term Success: By effectively reducing the tibial slope, this procedure significantly lowers the risk of future ACL graft failure, promoting knee stability and function.
Conclusion: Slope reducing osteotomy is a critical intervention for patients with multiply failed ACL reconstructions due to excessive posterior tibial slope. By correcting the slope, this procedure enhances the success of ACL revisions.
Anterior Tibial Slope Reducing Osteotomy for Revision ACL Reconstruction
