The Hip: Preservation, Replacement and Revision

Peroneal Nerve Palsy

peroneal nerve
    - peroneal palsy following TKR
    - nerve injury
    - discussion:
         - peroneal nerve palsy may lead to severe disability w/ foot drop and paresthesias;
         - note that in contrast to other types of nerve palsies, peroneal palsy may demonstrate a greater motor deficit (than sensory deficit) because the deep motor brach is subject to tethering a two points: the fibular neck and the intermuscular septum;
         - traumatic peroneal palsy: may result from supracondylar frx, knee dislocation, and proximal tibial frx;
         - atraumatic peroneal nerve palsy:
                   - may result from a large fabella which impinges on peroneal nerve behind knee or may result from a proximal tibiofibular synovial cyst (which is identifed by MRI);
                   - these patients will often have a history of lumber disc disease, ETOH use, and diabetes.
                   - reference:
                          - Unusual manifestations of proximal tibiofibular joint synovial cysts.  
    - exam:
         - always consider lumbar radiculopathy during the examination;
         - there may be an obvious foot drop;
         - sensory loss may be difficult to determine because of variable & small autonomous zone of sensation;
         - Tinel's sign over the fibular neck, helps localize the site of nerve compression;
         - always check for a fabella and check to see if direct compression reproduces nerve symptoms;
         - in cases of knee dislocation it is important to test for function of the tibial branch of the sciatic nerve as well;
               - in some cases of peroneal nerve avulsion, there will also be a sciatic nerve traction injury;
    - EMG:
         - useful to objectively document the conduction block;
         - if possible should be performed w/ in one month of injury;
         - amplitude of the sensory potential and decreases in nerve conduction velocities are used to confirm sensory and motor deficits, respectively;
    - prognosis;
         - w/ partial nerve palsy, > 80% will recover completely;
         - w/ complete palsy, < 40% will have complete recovery;
         - peroneal nerve in continuity which arises from a well defined etiology will tend to do better than nerve palsies arising from idiopathic causes;
    - treatment:
         - if there is no neurologic improvement after 2-3 months, then operative decompression is indicated;
         - nerve in continuity:
                - operative treatment invovles external neurolysis of peroneal nerve at the level of the fibular head;
                - nerve and its branches need to be freed from its adherence to the proximal fibula, particularly at its most proximal 4 cm as well as a 2nd region of adherence which may lie between 7 and 15 cm from the fibular head;
                - nerve may be entrapped by thick fibrous bands which arch over the nerve as it crosses the fibular neck;
                          - the arch has a superficial band and a deep band;
         - nerve not in continuity: (neurotomesis)
                - see nerve repair
                - one of the problems encountered in peroneal nerve repair following knee dislocations (or other injuries) is that the location of the nerve injury may be well above the knee joint;
                         - in the case of knee dislocation, there may be concomitant tibial nerve division palsy;
         - references: 
                - Nerve grafting for traction injuries of the common peroneal nerve. A report of 17 cases.
                - The operative treatment of peroneal nerve palsy.   
                - Decompression of the common peroneal nerve: experience with 20 consecutive cases.
                - Fibular fibrous arch.  Anatomical considerations in fibular tunnel syndrome.  
                - Anatomic variations related to decompression of the common peroneal nerve at the fibular head. 

- Tendon Transfers:
                - Posterior Tibial Tendon Transfer: Results of Fixation to the Dorsiflexors Proximal to the Ankle Joint 
                - Combined anteroposterior tibial tendon transfer in post-traumatic peroneal palsy.  
                - Anterior transplantation of the posterior tibial tendon for persistant palsy of the common peroneal nerve
                - Early Active Motion versus Immobilization after Tendon Transfer for Foot Drop Deformity: A Randomized Clinical Trial

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Thursday, January 10, 2013 12:57 pm