In a young, active patient with a stable central‑lateral trochlear groove osteochondral lesion ≤1 cm² and minimal symptoms, how should it be managed?

Management of Central-Lateral Trochlear Groove Osteochondral Lesions ≤1 cm²

In young, active patients with stable central-lateral trochlear groove osteochondral lesions ≤1 cm² and minimal symptoms, initial conservative management with activity modification and quadriceps strengthening should be attempted for 3-6 months, followed by arthroscopic microfracture if symptoms persist. 1

Initial Conservative Management (First-Line)

For stable lesions with minimal symptoms, begin with a 3-6 month trial of non-operative treatment: 1, 2

• Activity modification: Eliminate high-impact loading activities (running, jumping, pivoting sports) while maintaining low-impact cardiovascular fitness 3
• Quadriceps strengthening: Initiate isometric quadriceps exercises immediately to improve knee stability and reduce mechanical stress on the subchondral bone 3
• NSAIDs: Use topical formulations for inflammation control during symptomatic periods 3
• Weight optimization: Target BMI <25 kg/m² if overweight to decrease mechanical load 3

Monitor for mechanical symptoms (locking, catching), persistent effusion, or point tenderness that would indicate lesion instability and prompt earlier surgical intervention. 1

Surgical Management Algorithm (When Conservative Treatment Fails)

For Lesions <1 cm² with Intact Cartilage but Subchondral Pathology

Arthroscopic microfracture is the preferred first-line surgical option: 1, 3

• Indications: Focal, contained lesion <4 cm² (your lesion qualifies), minimal osteoarthritis, stable surrounding cartilage, intact subchondral plate 1
• Technique specifics: Debride friable cartilage to create perpendicular edges of healthy cartilage, then create 3-4 mm deep holes spaced 3-4 mm apart using a microfracture awl until bleeding visualized 1
• Expected outcomes: 93% ± 17% defect fill at second-look arthroscopy (mean 17 months), with significant improvement in pain and function scores 1
• Advantages: Single-stage procedure, no donor site morbidity, arthroscopic technique with minimal invasiveness 1

For Lesions <1 cm² with Unstable or Detached Fragments

If the osteochondral fragment is salvageable, internal fixation with bioabsorbable pins is preferred over excision: 4, 5

• Fixation technique: Use bioabsorbable compression screws or pins for rigid fixation of the fragment 5
• Consider lateral retinacular lengthening: In lateral trochlear groove lesions, simultaneous lateral retinacular lengthening prevents recurrence and achieves 94% patient satisfaction with return to sport 5
• Outcomes: Lysholm scores improve from 68.7 to 93.4, with 88% returning to same or higher athletic ability 5

Alternative: Osteochondral Autograft (Mosaicplasty)

For lesions that fail microfracture or have significant subchondral bone involvement, mosaicplasty is the definitive treatment: 1, 3, 6

• Indications: Age <45 years, no osteoarthritis, focal full-thickness lesion <3 cm² (your patient qualifies) 1
• Graft harvest site: Lateral trochlea non-weightbearing surface 3, 6
• Advantages over microfracture: Provides hyaline cartilage (superior mechanical properties to fibrocartilage), single-stage procedure, immediate weight-bearing permitted 1, 6
• Main limitation: Donor site morbidity, though this can be minimized with careful technique 6

Postoperative Rehabilitation Protocol

Early mobilization is critical to prevent stiffness while protecting the repair: 7

• Immediate (Days 1-7): Begin passive range-of-motion exercises and isometric quadriceps activation (straight-leg raises) 7
• Week 1: Initiate weight-bearing as tolerated; immediate full weight-bearing does not compromise healing 7
• Week 3: Introduce closed kinetic-chain exercises (leg press) for improved functional outcomes 7
• Weeks 4-6: Avoid open kinetic-chain exercises until ≥4 weeks post-surgery (restrict to 90°-45° knee flexion only) 7

Critical rehabilitation pitfall: Do NOT immobilize for 4 weeks—this increases stiffness without improving stability. However, avoid overly aggressive therapy in the first 6 weeks to protect fixation. 7

Procedures to Avoid

Arthroscopic debridement alone (without microfracture or repair) provides no benefit over conservative management and should not be performed for degenerative lesions. 3

When to Consider Osteochondral Allograft

Reserve allograft transplantation for larger lesions (>2.5 cm²) or revision cases with substantial subchondral bone loss—not indicated for your patient's ≤1 cm² lesion. 1, 3, 6