Courtesy: Dr S Macdonald, Ashok Shyam, Ortho TV

Flexion contracture is frequently encountered in advanced osteoarthritis—particularly in populations presenting late. It significantly affects gait mechanics and functional recovery.

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Why It Matters

• Flexion contracture increases quadriceps workload.

• Bilateral 30° contractures ? ~50% increase in quadriceps effort.

• Leads to:

  • Energy-inefficient gait

  • Reduced walking endurance

  • Poor postoperative satisfaction if uncorrected

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Grading of Flexion Contracture

Grade 2 and 3 deformities are commonly seen in advanced OA.

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Pathoanatomy

Structures contributing to flexion deformity:

• Posterior capsule

• Posterior cruciate ligament (PCL)

• Posterior osteophytes (femur and tibia)

• Hamstrings

• Gastrocnemius

• Posterior soft tissue envelope

In inflammatory arthritis:

• Additional posterior bone loss contributes.

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?? Important Principle

Avoid correcting flexion deformity by excessive distal femoral resection alone.

Over-resection leads to:

• Flexion instability

• Raised joint line

• Poor long-term function

Always prioritize soft tissue correction first.

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Three-Stage Management Strategy

1?? Preoperative Measures

Limited role, but useful in select cases:

• Serial manipulation

• Serial casting

• Epidural-assisted stretching (especially inflammatory arthritis)

• Correct hips first if bilateral hip and knee involvement

?? Risk: Supracondylar fracture during aggressive manipulation.

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2?? Intraoperative Management (Key Phase)

Step 1: Adequate Exposure

• Standard approach.

• Maintain measured bone resection technique.

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Step 2: Posterior Osteophyte Removal (Critical Step)

• Remove femoral and tibial posterior osteophytes completely.

• Use curved osteotome or rongeur.

• Work carefully under the MCL.

• Recreate posterior recess.

This alone often significantly reduces contracture.

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Step 3: Posterior Soft Tissue Release

• Subperiosteal release from posterior femur.

• Can safely extend deep without vascular compromise if performed correctly.

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Step 4: Tibial Slope

• Minimum ~5° posterior slope recommended.

• Inadequate slope may perpetuate flexion tightness.

• Particularly important in CR knees.

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Step 5: PCL Management

• PCL sacrifice often required in moderate-to-severe deformity.

• CR correction possible in selected mild cases.

• PS or constrained designs often preferred in severe cases.

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Step 6: Posterior Capsulotomy

• Performed under direct visualization.

• Can be done in flexion or extension.

• Use laminar spreaders.

• Release central posterior capsule carefully.

Almost always required in Grade 2–3 deformities.

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Step 7: Gastrocnemius Release (Selective)

• Consider in severe fixed deformity.

• Especially when posterior tightness persists.

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Step 8: Distal Femoral Recut (Last Resort)

• If contracture persists:

  • Additional 2 mm distal femoral resection.

• Avoid excessive resection.

• Preserve joint line integrity.

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3?? Postoperative Management

Key Principles

• No pillow under the knee.

• Pillow under heel to maintain extension.

• Night knee immobilizer.

• Controlled use of CPM.

• Aggressive extension exercises.

Failure in postoperative extension positioning can undo intraoperative correction.

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Correction Expectations

Osteoarthritis

• Aim for full correction.

• Up to 10° residual deformity may gradually correct over time.

Rheumatoid Arthritis

• Full correction not always achievable.

• Functional improvement more important than absolute zero deformity.

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Additional Considerations

Patella Baja

• Avoid excessive distal femoral resection.

• Avoid joint line elevation.

• May consider:

  • Tibial resection adjustments

  • AP femoral sizing modifications

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Severe Contracture (Extreme Cases)

• Consider:

  • Medial capsule advancement

  • Quadriceps slide

  • Double-breasting technique

  • Constrained implants if instability present

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Complications to Watch For

• Neurovascular injury

• Wound healing problems

• Recurrent deformity

• Ligament instability

• Posterior subluxation

Careful, stepwise correction minimizes these risks.

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Practical Algorithm

1. Remove posterior osteophytes.

2. Posterior capsular release.

3. PCL sacrifice (if needed).

4. Gastrocnemius release (if needed).

5. Reassess extension gap.

6. Additional distal femoral resection only if necessary.

7. Consider constrained implant if instability.

8. Enforce strict postoperative extension protocol.

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Final Clinical Pearls

• Do not rush bone resection.

• Soft tissue correction is primary.

• Joint line preservation is critical.

• Focus is essential in severe deformities.

• Inadequate attention ? instability disaster.