Courtesy: Dr Strickland, Ashok Shyam TV, Ortho
Background and Evolution of Treatment
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Medial patellofemoral ligament reconstruction was rarely performed two decades ago.
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The ligament was historically under-recognized in patellar instability.
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Over the last 12 to 13 years, understanding of its importance has significantly increased.
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Patellar instability can lead to:
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Loss of athletic participation for an entire season in approximately 20 percent of patients.
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High incidence in young female athletes, including gymnastics, soccer, lacrosse, and football.
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Significant disability with prolonged nonoperative management in many cases.
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Associated Injuries and Long-Term Risks
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Osteochondral or chondral injury is common following patellar dislocation.
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Some patients progress to generalized knee osteoarthritis.
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Instability symptoms do not necessarily correlate with severity of cartilage damage.
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Careful evaluation is required in every case.
Historical Procedures
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Several older surgical procedures for patellar instability demonstrated poor outcomes.
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Some techniques have been abandoned due to high failure rates.
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Modern treatment focuses on anatomical restoration and risk-based decision making.
Treatment Algorithm Overview
First-Time Dislocator
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If cartilage injury is present:
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Surgical management should be strongly considered.
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Reconstruction of the medial patellofemoral ligament should be included.
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If no cartilage injury:
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Risk factors must guide decision-making.
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High-risk patients should have a surgical discussion.
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Multiple Dislocators
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Surgical management is generally recommended.
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Medial patellofemoral ligament reconstruction is indicated in most cases.
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Nonoperative treatment is rarely appropriate after multiple instability episodes.
Predicting Recurrence
Certain patients have significantly higher recurrence rates.
High-Risk Features
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Patella alta
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Trochlear dysplasia
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Age younger than 25 years
These patients may have:
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Approximately 70 percent five-year recurrence risk.
Additional predictive factors:
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Skeletal maturity
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Trochlear dysplasia severity
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Patella alta measurements
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Contralateral patellar dislocation history
Patients with prior contralateral dislocation:
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Three times higher risk of instability.
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Prior instability in either knee increases recurrence risk significantly.
Special Considerations in Skeletally Immature Patients
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Open growth plates limit surgical options.
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Bony procedures are contraindicated.
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Medial patellofemoral ligament reconstruction is the primary surgical option.
Isolated Medial Patellofemoral Ligament Reconstruction
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In many cases, isolated reconstruction provides good short-term outcomes.
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Published studies show favorable results at one to two years.
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Long-term data beyond five years are critical for true success evaluation.
Clinical Examination Pearls
Patellar Tilt Assessment
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Patient in full extension.
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Both hands used to center patella.
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Assess ability to evert lateral facet to neutral.
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Tight lateral restraints may require lateral lengthening.
Important Warning
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Do not perform lateral release or lengthening in patients with generalized ligamentous laxity (high Beighton score).
Femoral Tunnel Placement: Critical Factor
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Most failures are due to incorrect femoral tunnel placement.
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Incorrect positioning results in:
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Non-isometric graft behavior.
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Tunnel widening.
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Overconstraint.
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Poor clinical outcomes.
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Key Principles
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Start at the palpable sulcus.
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Check graft isometry carefully.
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Confirm positioning with fluoroscopy in every case.
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Avoid placing the tunnel too high and too tight.
Improper placement may cause:
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Excessive graft tension.
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Patellar overload.
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Catastrophic failure.
Patellar Fixation Pearls
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Avoid violating patellar cortex.
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Avoid damaging articular cartilage.
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Incorrect anchor placement may lead to:
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Patellar fracture.
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Extensor mechanism compromise.
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Severe patient dissatisfaction.
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Preferred Technique
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All-suture anchors placed carefully.
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Avoid lateral facet violation.
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Avoid excessive anterior cortex weakening.
Graft Fixation Technique Overview
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Doubled graft attached to patella.
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Femoral tunnel created after confirming isometry and fluoroscopic position.
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Whip stitching of graft.
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Button or adjustable fixation device allows tension fine-tuning.
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Graft should not be overtightened.
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Goal is appropriate stability, not excessive constraint.
Case Example: Skeletally Immature Patient
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Young female patient with:
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Patella alta
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Trochlear dysplasia
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High tibial tubercle to trochlear groove distance
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Osteotomy desired but not possible due to open growth plate.
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Large osteochondral fragment identified.
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Surgical plan:
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Medial patellofemoral ligament reconstruction.
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Cartilage repair if fragment viable.
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Fixation with absorbable implants when possible.
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Cartilage Management Principles
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If fragment viable:
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Repair is preferred.
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If fragment nonviable:
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Consider cartilage restoration procedures.
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Address cartilage injury at the index procedure whenever possible.
Key Surgical Pearls Summary
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Open growth plate:
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Only soft tissue procedures.
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Isolated medial patellofemoral ligament reconstruction often effective.
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Assess patellar tilt carefully.
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Avoid lateral release in hyperlax patients.
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Femoral tunnel accuracy is critical.
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Avoid patellar cortex and cartilage violation.
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Fine-tune graft tension.
Clinical Decision-Making Summary
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Risk stratification improves recurrence prediction.
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High-risk first-time dislocators should be counseled about surgery.
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Multiple dislocators generally require reconstruction.
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Cartilage injury mandates surgical consideration.
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Early cartilage fixation improves long-term joint preservation.
Conclusion
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Management of patellar instability has evolved significantly.
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Medial patellofemoral ligament reconstruction is central to treatment.
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Accurate surgical technique determines outcome.
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Risk factor assessment allows individualized care.
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Early and appropriate intervention may prevent recurrent instability and long-term degeneration.
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