synonyms: knee fusion, knee arthrodesis
Knee Arthrodesis CPT
Knee Arthrodesis Anatomy
- Final position for knee fusion = 7° ± 5° of valgus and 15° ± 5°of flexion. (Figgie HE III,CORR 1987;224:237)
Knee Arthrodesis Indications
- Failed TKA
- Irreparable extensor mechanism
- Young active patients involved in heavy labor
- Soft tissue defects
- Neuropathic joint disease
Knee Arthrodesis Contraindications
- Bilateral disease
- Ipsilateral hip arthrodesis
- Ipsilateral hip arthritis
- Ipsilateral ankle arthritis
Knee Arthrodesis Alternatives
- Resection arthroplasty
- Above-knee amputation (Falahee MH, JBJS 1987;69A:1013)
Knee Arthrodesis Pre-op Planning / Considerations
- Pre-op medical clearance is needed in most patients.
- A/P and lateral knee films, standing hip-to-knee alignment xrays. Evaluate pre-op alignment and varify hip and anke are free of significant arthritis. Nail length templated and any bony cuts or hardware removal needed is determined.
- Pre-operative trial of in cylinder cast or knee immobilizer is valuable to demonstrate post-operative functional abililites to patients.
- Infection should be eradicated before fusion.
Knee Arthrodesis Techniques
Knee Arthrodesis IM Nail Technique
- Pre-operative antibiotic.
- Supine position with bump under hip.
- Anesthesia: Consider peripheral nerve blocks (Horlocker TT, JAAOS 2006;14:126)
- Bony prominences well padded
- Consider foley catheter
- Mid-line longitudinal incision. Use the most lateral longitudinal parapatellar incision when previous multiple incisions are present. (Vince KG, ICL 1993;42:325)
- Medial parapatellar arthrotomy
- Previous TKA components removed.
- Bone ends cut to ensure bone on bone contact.
- Tibia is reamed first to deterimine nail size.
- Femus and tibia shafts prepared and nail placed per IM nail manufactures technique guide.
- Close in layers.
- Knee immobilizer or cylinder cast.
Knee Arthrodesis Complications
Knee Arthrodesis Follow-up
- Post-operative weight-bearing status is depended on type of fixation used and the amount of bone on bone contact achieved. Generally partial weight-bearing until evidence of bony fusion is seen on xray.
- TKA after arthrodesis has high risk of complication including skin necrosis, infection, and instability.
Knee Arthrodesis Outcomes
- 83% union, average time to union =5.5 months, average limb-length discrepancy = 5.5 cm. Complications = above-the-knee amputation for recurrence of infection, nail breakage three years after implantation. (Bargiotas K, JBJS 2006;88A:553).
Knee Arthrodesis Review References