Arthrofibrosis

Courtesy: Dr C Ranawat, Ashok Shyam TV, Ortho

Introduction

• Arthrofibrosis is an uncommon but frustrating complication after total knee arthroplasty (TKA).

• Incidence: < 2% following primary TKA.

• Defined as:

  • Functional impairment with restricted knee motion.

• Important distinction:

  • Not all stiff knees are arthrofibrotic.

---

Definition of a Stiff Knee

• Knee flexion < 75° generally considered stiff.

• However:

  • Stiffness ? Arthrofibrosis.

  • Arthrofibrosis is a diagnosis of exclusion.

---

Causes of Postoperative Stiffness

Preoperative Factors

• Multiple previous knee surgeries.

• Ankylosed or severely deformed knees.

• Poor preoperative range of motion.

---

Intraoperative Technical Errors

• Inaccurate ligament balancing.

• Oversized components.

• Joint line elevation.

• Patella infera.

• Femoral component malrotation (especially internal rotation).

---

Postoperative Causes to Rule Out

Before diagnosing arthrofibrosis, exclude:

• Deep infection.

• Complex regional pain syndrome (CRPS / RSD).

• Heterotopic ossification.

---

Complex Regional Pain Syndrome (CRPS) vs Arthrofibrosis

CRPS features:

• Vasomotor disturbances.

• Hyperesthesia.

• Excessive sweating.

• Periarticular osteoporosis.

Diagnostic/therapeutic option:

• Lumbar sympathetic block.

• Possible lumbar sympathectomy in refractory cases.

These features are not typical in arthrofibrosis.

---

Pathophysiology of Arthrofibrosis

• Periarticular fibrosis.

• Formation of dense scar bands between:

  • Extensor mechanism.

  • Distal femur.

• Obliteration of medial and lateral gutters.

• Reduced patellar mobility.

Proposed Mechanisms

• T-cell mediated immune response.

• Overexpression of TGF-? (transforming growth factor beta).

• Excess collagen deposition (type VI collagen predominance).

---

Predisposing Factors

• Keloid tendency.

• HLA-B8 association (reported).

• Poor pain tolerance.

• Noncompliance with rehabilitation.

• Certain personality traits (poor participation in therapy).

---

Clinical Presentation

• Pain and stiffness.

• Warmth and swelling.

• Reduced range of motion.

• Antalgic gait.

• Flexed-knee posture.

May mimic infection.

---

Diagnostic Workup

Radiographs

• Assess:

  • Implant positioning.

  • Joint line.

  • Tibial slope.

  • Component alignment.

CT Scan

• Useful if femoral component malrotation suspected.

• Internal rotation of femoral component strongly associated with postoperative stiffness.

---

Management Algorithm

0–3 Weeks Postoperative

• Aggressive physiotherapy.

• Dynamic splinting.

• Continuous passive motion (CPM).

• Ensure adequate pain control (critical).

---

3–6 Weeks

• Consider manipulation under anesthesia (MUA) if progress inadequate.

• Must ensure:

  • Complete muscle relaxation.

  • Controlled technique.

Risks:

• Periprosthetic fracture.

• Extensor mechanism disruption.

Evidence suggests:

• Intra-articular analgesic cocktail may improve motion gains.

---

Beyond 6 Weeks

If persistent stiffness:

Arthrolysis

• Arthroscopic:

  • Less invasive.

  • May be limited by visualization.

• Open:

  • Radical scar excision.

  • Medial and lateral gutter release.

  • Quadriceps pie-crusting if needed.

  • Polyethylene exchange (thinner insert).

---

Revision Surgery

Indicated only if:

• Identifiable technical error.

• Malalignment.

• Internal rotation of femoral component.

• Elevated joint line.

If femoral component internal rotation present:

• Physiotherapy and manipulation unlikely to succeed.

• Revision required.

---

Principles of Revision

• Wide exposure.

• Consider:

  • Quadriceps snip.

  • Tibial tubercle osteotomy.

• Complete scar excision.

• Correct component alignment.

• Restore joint line.

• Ensure optimal postoperative pain control.

---

Summary Algorithm

1. Reduced ROM after TKA ? Evaluate clinically.

2. Rule out:

   • Infection.

   • CRPS.

   • Heterotopic ossification.

3. 0–3 weeks ? Aggressive rehab.

4. 3–6 weeks ? Manipulation under anesthesia.

5. 6 weeks ? Arthrolysis.

6. Revision only if technical error identified.

---

Key Take-Home Messages

• Arthrofibrosis is uncommon but challenging.

• It is a diagnosis of exclusion.

• Adequate pain control is essential for prevention.

• Early intervention improves outcomes.

• Revision should only be done when a correctable cause is identified.

• Further research needed into immune modulation and genetic predictors.