TKA Neurovascular Injury

Epidemiology of Neurovascular Injury

Nerve Injury

Common peroneal nerve palsy is the most frequent neurological complication following TKA, occurring in 0.3-1.3% of primary cases. [1,2] The incidence increases substantially in revision procedures and complex primary cases.

Risk stratification by deformity:

• Valgus greater than 10°: 3.3% peroneal nerve palsy rate
• Valgus greater than 15°: 6-9.5% peroneal nerve palsy rate
• Flexion contracture greater than 20°: 4-5% nerve palsy rate [1,3]

Vascular Injury

Vascular complications are rare but carry significant morbidity and mortality:

• Overall incidence: 0.03-0.17% of TKA procedures [4,5]
• Popliteal artery injury most common vascular complication
• Delayed presentation (pseudoaneurysm, AVF) may occur weeks to months post-operatively
• Mortality rate: 5-7% when vascular injury occurs
• Amputation rate: 10-42% in delayed recognition [4]

Australian Context

The Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) does not specifically capture neurovascular complications, but Australian data suggests similar rates to international literature. High-volume centres with fellowship-trained arthroplasty surgeons demonstrate lower complication rates. Patients with peripheral vascular disease should be optimized pre-operatively with vascular surgery input when indicated.

Critical Neurovascular Anatomy

Understanding the anatomical relationships in the popliteal fossa and around the proximal fibula is essential for both prevention and management of neurovascular complications.

Popliteal Fossa Contents

From superficial to deep (posterior to anterior):

1. Tibial nerve - most posterior, crosses popliteal vessels from lateral to medial
2. Popliteal vein - intermediate position
3. Popliteal artery - deepest structure, closest to posterior capsule

Key distances from bone:

• Popliteal artery lies approximately 5-10mm posterior to the posterior tibial cortex with knee in extension [6]
• Distance decreases with knee flexion beyond 90°
• Tethered by genicular branches - limited mobility
• Most vulnerable during posterior capsule release and tibial cutting

Common Peroneal Nerve Course

Course of common peroneal nerve:

1. Originates from sciatic nerve at apex of popliteal fossa (variable level)
2. Descends along medial border of biceps femoris tendon
3. Wraps around fibular neck - superficial, vulnerable location
4. Only 2-3mm of connective tissue between nerve and bone at fibular neck
5. Divides into superficial and deep peroneal nerves

Why the peroneal nerve is vulnerable:

Proximal Tibiofibular Joint Anatomy

Clinical correlates:

• Lateral retractor placement must avoid fibular head
• Peroneal nerve can be directly visualized if in doubt
• Release of ITB and lateral structures places nerve at risk
• Proximal tibiofibular joint arthritis/osteophytes may alter anatomy

Vascular Anatomy Relevant to TKA

Popliteal artery branches in the knee region:

High-risk maneuvers for popliteal artery injury:

1. Posterior capsule release (closest proximity)
2. Posterior tibial osteophyte removal
3. Oscillating saw during tibial cut (over-penetration)
4. Anterior tibial retractor placement (impingement)
5. Tibia extraction after cementation

Patient and Surgical Risk Factors

Pre-operative Risk Factors

Intra-operative Risk Factors

Recognition of Neurovascular Injury

Nerve Injury Presentation

Vascular Injury Presentation

Acute Arterial Injury:

Delayed Vascular Issues:

Differential Diagnosis of Post-TKA Foot Drop

Surgical Techniques to Minimize Risk

Pre-operative Planning

Patient Assessment:

• Document pre-operative neurological status (ankle dorsiflexion, sensation)
• Assess peripheral pulses and ABI if vascular disease suspected
• Consider vascular surgery consultation for calcified vessels/prior vascular surgery
• Review previous surgical records for anatomical variations
• Inform patient of increased risk if risk factors present

Surgical Planning:

• Templating to predict required correction
• Consider constrained implants for severe deformity (reduce soft tissue release)
• Plan for staged correction if greater than 15° valgus
• Have vascular surgery backup if high-risk case

Intra-operative Prevention

Post-operative Monitoring

Neurovascular Observations:

• Document pulses and ankle dorsiflexion in recovery
• Repeat examination when regional block wears off
• Monitor for compartment syndrome (especially if tourniquet used)
• Low threshold for dressing loosening if concerns

High-Risk Protocol:

• Splint knee in 30-45° flexion for 48-72 hours
• Serial neurological examinations
• Early physiotherapy input
• Consider routine Doppler assessment if vascular concern

Imaging Gallery

Imaging in Neurovascular Injury:

Nerve Conduction Studies / EMG:

• Not useful in acute setting (requires 2-3 weeks for Wallerian degeneration)
• Baseline at 3-4 weeks if no recovery
• Repeat at 3 months to assess recovery
• Useful to differentiate neurapraxia from axonotmesis
• Can localize level of lesion

Stepwise Management Approach

📊 Management Algorithm

Click to expand

Acute Nerve Palsy Management

Acute Vascular Injury Management

Management by Injury Type:

Fasciotomy Technique:

• All 4 compartments must be released
• Single lateral incision can access anterior, lateral, and superficial posterior
• Separate posteromedial incision for deep posterior
• Leave wounds open - delayed primary closure or skin grafting

Prognosis and Recovery

Peroneal Nerve Palsy Outcomes

Recovery Rates:

• Complete recovery: 50-90% (literature varies widely)
• Partial recovery: 10-30%
• No recovery: 5-20%
• Mean recovery time: 12-18 months
• Maximum recovery typically by 2-3 years

Functional Outcomes:

• Most patients with complete recovery have normal function
• Patients with AFO-dependent foot drop can still ambulate
• Patient satisfaction lower than uncomplicated TKA
• Consider revision or tendon transfer for permanent deficit

Vascular Injury Outcomes

Outcomes by Recognition Timing:

Long-term Outcomes:

• Patients with limb salvage may have claudication
• Repeat intervention may be required
• Chronic pain and disability common
• Litigation risk significant

Medicolegal Considerations

• Neurovascular injury is a recognized complication of TKA
• Documentation of consent discussion essential
• Pre-operative neurological status should be documented
• Post-operative examination must be timely and documented
• Delayed recognition is the most common source of litigation

References

1. Schinsky MF, Macaulay W, Parks ML, Kiernan H, Nercessian OA. Nerve injury after primary total knee arthroplasty. J Arthroplasty. 2001;16(8):1048-1054.

2. Idusuyi OB, Morrey BF. Peroneal nerve palsy after total knee arthroplasty. Assessment of predisposing and prognostic factors. J Bone Joint Surg Am. 1996;78(2):177-184.

3. Nercessian OA, Ugwonali OF, Park S. Peroneal nerve palsy after total knee arthroplasty. J Arthroplasty. 2005;20(8):1068-1073.

4. Calligaro KD, Dougherty MJ, Ryan S, Booth RE. Acute arterial complications associated with total hip and knee arthroplasty. J Vasc Surg. 2003;38(6):1170-1177.

5. Rand JA. Vascular complications of total knee arthroplasty. Report of three cases. J Arthroplasty. 1987;2(2):89-93.

6. Ninomiya JT, Dean JC, Goldberg VM. Injury to the popliteal artery and its anatomic location in total knee arthroplasty. J Arthroplasty. 1999;14(7):803-809.

7. Asp JP, Rand JA. Peroneal nerve palsy after total knee arthroplasty. Clin Orthop Relat Res. 1990;(261):233-237.

8. Rose HA, Hood RW, Otis JC, Ranawat CS, Insall JN. Peroneal nerve palsy following total knee arthroplasty. A review of The Hospital for Special Surgery experience. J Bone Joint Surg Am. 1982;64(3):347-351.

9. Horlocker TT, Hebl JR, Gali B, et al. Anesthetic, patient, and surgical risk factors for neurologic complications after prolonged total tourniquet time during total knee arthroplasty. Anesth Analg. 2006;102(3):950-955.

10. Mont MA, Dellon AL, Chen F, Hungerford MW, Krackow KA, Hungerford DS. The operative treatment of peroneal nerve palsy. J Bone Joint Surg Am. 1996;78(6):863-869.

11. Parvizi J, Pulido L, Slenker N, Macgibeny M, Purtill JJ, Rothman RH. Vascular injuries after total joint arthroplasty. J Arthroplasty. 2008;23(8):1115-1121.

12. Abularrage CJ, Nassiri N, Shao H, Borg BB, Mukherjee D, Perler BA, Lipsitz EC. Arterial injury during primary total joint arthroplasty: a 13-year review of 5,067 cases. J Vasc Surg. 2013;58(1):220-225.