What is the Role of Lateral Retinacular Release?

Reviewed by Dr Nathan White MBBS | Unaccredited Orthopaedic Registrar

Indications

  • Anterior knee pain
  • Patellar instability
  • Patellofemoral osteoarthritis
  • Knee replacement

Patellar stability

  • Soft tissue stabilisers
    • Active: VMO
    • Passive: medial PF ligament, lateral retinaculum
  • Bony influences
    • Q angle
    • Trochlear morphology

Principles

  • symptoms due to dynamic imbalance between medial and lateral constraining forces.
  • Patello-femoral biomechanics vs symptoms
    • Complex relationship between soft tissue and bony anatomy
    • Biomechanics alone does not always correlate with pain or instability

Biomechanical Effects of Lateral Release

  • Centre of PF contact pressure medialised in 60-120 flexion
  • Reduced force required for lateral displacement
  • May theoretically worsen instability symptoms
  • Progressive release from proximal 1/3 vastus lateralis to mid patella then Gerdy’s tubercle: mid part contributes most to medial stability
  • Issues
    • How much is too much?
    • Does biomechanical evidence translate into symptomatic relief?

Lateral release for Anterior knee pain

  • Results
    • Satisfaction 14 – 100%
  • Literature
    • Variable pt selection, evaluation, follow up
  • Outcome results
    • Poor outcome
      • Female (young, fail to regain strength)
      • Inadequate realignment, malalignment
      • Grade III – IV articular changes
    • Better outcome
      • Sage sign +, tilt on CT
  • Points of interest
    • Patellar tilt and displacement improved
    • No improvement in function at 4 years
    • Complex pathology
    • Possibility of transient improvement due to lateral retinaculum dennervation
  • Recommendations
    • Sage +, patellar tilt on CT
    • Absence of articular cartilage damage

Lateral release for Patellar instability

  • Results
    • Satisfaction 30 – 100%
    • Significant reduction over time

Lateral release for Patellofemoral Osteoarthritis

  • Lateral release alone uniformly poor outcome
  • Exception: combined with PFJ bipolar debridement

Lateral Release in TKR

  • Variable findings
  • Increased rate of patellar vascular compromise on bone scan – up to 50%
  • Reduced oxygen concentration at lateral wound edge
  • Correlation with symptoms, wound complications, or patellar revision surgery?
  • Avoid: consider femoral component

Complications Following Lateral Release

  • Haemarthrosis
    • Superior lateral geniculate
    • Minimise with open or arthroscopic diathermy
  • Medial instability
  • CRPS

Take home message

  • Literature
    • Poorly described inclusion / exclusion
    • Non standardised assessment: satisfaction
    • Proposed indications cover heterogenous patient group
  • Limited clear indications for Latera Release
    • Careful patient selection
    • Anterior pain: Sage +, CT evidence of patellar tilt
    • Instability: rarely alone, consider other factors
    • TKR: prevention