Knee joint trauma or injury can cause isolated peroneal nerve laceration. An injury to the peroneal nerve is generally caused by an impact or trauma on the outside of the knee causing numbness and tingling. The diagnosis of knee joint trauma or injury and peroneal nerve injury causing peroneal nerve palsy is confirmed during physical assessment following trauma. Patient is seen by neurologist, physiatrist, podiatrist, orthopedic spine surgeon, or a neurosurgeon for further evaluation, investigation and treatment of knee joint trauma and peroneal nerve injury.
Most common symptom and sign suggesting peroneal nerve injury is individual showing signs of footdrop and having difficulty walking on heels. Tests such as MRI or EMG are done to further confirm the diagnosis.
About Peroneal Nerve
The peroneal nerve emanates from the sciatic nerve, which runs down the outside of the lower leg and supplies the peroneal muscles. These muscles facilitate inversion of the foot and upward movement of the foot.
Causes of Peroneal Nerve Injury:
- Knee Joint Injury- Injury or trauma to the outer portion of the knee results in injury to the peroneal nerve since it is present very close to the skin.
- Peroneal Nerve Injury- Most of the accidental injuries causing peroneal nerve laceration or tear are caused by domestic fall, car and work accident.
- Soft Tissue Inflammation- Soft tissue inflammation, and subcutaneous abscess close to peroneal nerve causes peroneal nerve injury.
- Fibular Fracture- Fracture of fibula causes knee joint injury and peroneal nerve laceration resulting in foot drop.1
- Knee Dislocation- Knee joint trauma such as knee joint dislocation causes peroneal nerve injury caused by nerve laceration and tear.2
- Surgery- Knee joint surgery may result in knee joint trauma and peroneal nerve injury. Skin incision if close to peroneal nerve, then peroneal nerve injury may result from skin incision.3
- Pressure Over Peroneal Nerve- Prolonged pressure to the outer portion of the knee such as in people who cross their legs with sitting or wear tight clothes can cause peroneal nerve injury.
- Bone Cancer- Benign or malignant bone cancer may infiltrate into peroneal nerve resulting in severe damage.4
Symptoms of Peroneal Nerve Injury On Knee Joint:
- Swelling- Knee joint swelling is observed. Swelling is caused by hematoma and soft tissue edema. Swelling, hard in consistency, could be dislocation of fracture of tibia, fibula or femur.
- Pain- Severe intractable pain of knee joint.
- Dislocation- Dislocation of knee joint may result in abnormal shape of knee joint. Patient is unable to flex or extend knee joint.2
- Fracture- Fracture of knee joint may result in abnormal shape of knee joint and movement. Severe pain is observed with palpation of the joint or movement.
General Symptoms Of Peroneal Nerve Injury Are:-
- Numbness or tingling on the anterior side or on top of the foot.
- Reduced sensation to touch.
- Weakness with lifting the foot in an upward direction and turning it outwards.
- Loss of function of the foot.
- Severe cases of peroneal nerve injury results in footdrop meaning the inability of a person to lift the foot up when ambulating.
- Presence of a slapping gait where the foot slaps on the ground during ambulation due to inadequate control over muscles.
- Symptoms of the peroneal nerve injury are similar to symptoms produced as a result of compression of the nerve at a level above usually at the nerve root.
Treatment for Peroneal Nerve Injury:
- Non-Steroidal Anti-Hypertensive Medications (NSAID)-
- Prescribed for inflammation and pain.
- Most common NSAIDs prescribed are Celebrex, Motrin and Naproxen.
- Exercise To:
- Improve foot drop
- Improve power and tone of foot and leg muscles.
- Foot drop because of muscle weakness and paralysis interferes with walking and standing. Gait training is part of the physical therapy to prevent falling down and tripping.
- TENS (Transcutaneous Electrical Nerve Stimulation) Unit
- TENS unit is used to relieve the pain and also cause muscle contraction, which helps to improve tone and power of the leg and foot muscles.
Interventional Pain Therapy For Peroneal Nerve Injury
- Corticosteroid Injection-
- Corticosteroid injection of knee joint and peroneal nerve helps to reduce pain intensity and improve inflammation. Initially a course of 3 injections are tried, if pain relief is satisfactory then cortisone injection is recommended as a treatment every 3 to 4 months for 1 to 2 years.
Surgery For Peroneal Nerve Injury:
Surgical Treatment For Peroneal Nerve Injury Comprises Of
- Decompression Surgery5
- Nerve Sutures
- Nerve Grafting
- Nerve or Tendon Transfer
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Kim YC1, Jung TD.
Ann Rehabil Med. 2011 Oct;35(5):648-57.
2. Is Peroneal Nerve Injury Associated With Worse Function After Knee Dislocation?
Krych AJ1, Giuseffi SA, Kuzma SA, Stuart MJ, Levy BA.
Clin Orthop Relat Res. 2014 Feb 27.
3. Iatrogenic transection of the peroneal and partial transection of the tibial nerve during arthroscopic lateral meniscal debridement and removal of osteochondral fragment.
Wendt MC, Spinner RJ, Shin AY1.
Y. Am J Orthop (Belle Mead NJ). 2014 Apr;43(4):182-5.
4. Peripheral nerve injuries due to osteochondromas: analysis of 20 cases and review of the literature.
Göçmen S1, Topuz AK, Atabey C, Şimşek H, Keklikçi K, Rodop O.
J Neurosurg. 2014 May;120(5):1105-12.
5. Peroneal nerve entrapment at the fibular head: outcomes of neurolysis.
Maalla R1, Youssef M, Ben Lassoued N, Sebai MA, Essadam H.
Orthop Traumatol Surg Res. 2013 Oct;99(6):719-22.