What treatment options are available for a patellar subluxation where the knee frequently pops out of place but self-reduces?

Treatment of Recurrent Patellar Subluxation with Self-Reduction

Begin with a structured 3-6 month trial of conservative management centered on eccentric strengthening exercises, as this approach successfully resolves symptoms in approximately 80% of patients and surgery should only be considered after documented failure of well-executed conservative treatment. 1

Initial Conservative Management (First-Line Treatment)

Eccentric Strengthening Program

• Implement eccentric quadriceps exercises as the cornerstone of treatment, specifically targeting the vastus medialis obliquus (VMO) to improve patellar tracking and stability 1
• These exercises reduce symptoms, increase strength, and promote proper collagen alignment in the supporting structures 1
• Heavy slow resistance training serves as an evidence-based alternative to traditional eccentric protocols 1

Activity Modification

• Reduce repetitive loading activities that reproduce subluxation episodes, particularly jumping, pivoting, and stair navigation 1
• Implement relative rest rather than complete immobilization, as the latter causes muscular atrophy and deconditioning 1

Pain Management

• Use topical NSAIDs preferentially over oral formulations to eliminate gastrointestinal hemorrhage risk while providing short-term pain relief 1
• Apply cryotherapy through a wet towel for 10-minute periods for acute pain episodes 1

Adjunctive Manual Therapy

• Deep transverse friction massage to the patellar retinaculum reduces pain and may provide additional benefit 1

Diagnostic Imaging Pathway

Initial Radiographic Assessment

• Obtain knee radiographs as the initial imaging study, including anteroposterior, lateral, and tangential patellar views 2
• Look specifically for small osseous fragments along the medial patellar margin suggesting prior dislocation-relocation events 2

Advanced Imaging When Indicated

• Order MRI without IV contrast if radiographs show osseous fragments or clinical concern for recurrent instability persists 2
• MRI effectively evaluates medial patellofemoral ligament integrity, medial patellar retinaculum status, cartilage injury extent, and identifies loose bodies 2
• CT without IV contrast may be indicated to evaluate patellofemoral anatomy, trochlear morphology, and tibial tubercle-trochlear groove distance in cases of repetitive subluxation 2

Surgical Intervention Criteria

Timing and Indications

• Surgery is justified only after 3-6 months of well-managed conservative treatment has failed 1
• Additional surgical indications include inability to perform activities of daily living despite conservative treatment or documented associated pathology requiring intervention 3

Surgical Techniques

• Extensor mechanism realignment consisting of lateral patellofemoral ligament release, vastus medialis obliquus advancement, and in selected cases, tibial tubercle transfer 3
• Open or arthroscopic excision of abnormal tissue with longitudinal tenotomies to release scarring and fibrosis 1
• All surgical cases should include arthrotomy to assess and address intra-articular pathology 3

Evidence Regarding Surgical vs. Conservative Management

The evidence comparing surgical to non-surgical treatment for patellar dislocation remains very uncertain, with very low certainty evidence showing surgery may reduce recurrent dislocation risk (157 fewer per 1000 at 2-9 years) but with unclear effects on function scores and potentially higher adverse event rates (335 more complications per 1000) 4. Given this uncertainty and the high success rate of conservative treatment, the conservative-first approach is strongly justified.

Critical Pitfalls to Avoid

• Never inject corticosteroids directly into patellar supporting structures, as this inhibits healing, reduces tensile strength, and predisposes to spontaneous rupture 1
• Do not proceed to surgery without documenting an adequate 3-6 month trial of properly executed conservative treatment 1
• Avoid multiple corticosteroid injections as they weaken structural integrity despite providing short-term symptom relief 1
• If multiple tendons are symptomatic simultaneously, evaluate for underlying rheumatic disease 1
• Do not recommend complete immobilization, as this worsens outcomes through deconditioning 1

Expected Outcomes

• Approximately 80% of patients recover completely within 3-6 months with appropriate conservative treatment 1
• For the 20-27% requiring surgery after conservative failure, extensor mechanism realignment provides good results in terms of pain reduction, improved function, and patellar stability at average 3-year follow-up 3