This article describes a case of a 11-year-old boy with an osteochondroma of the peroneal head causing peroneal nerve palsy. Physical examination disclosed large exostoses palpated at the right fibular head. Neurological examination revealed paresis of the tibialis anterior, lateral peroneal, and extensor digitorum muscles with a muscle strength grade of 2. Electrophysiological studies confirmed denervation of the muscles supplied by the right peroneal nerve. Radiological examination showed an osteochondroma in the head of the right fibula. The patient underwent surgical decompression of the right peroneal nerve after resection of the bone tumor. At 36-month follow-up, there was a complete recovery of the deficits.
Peroneal mononeuropathy in children is uncommon. Osteochondroma is a benign tumor consisting of projecting bone capped by cartilage. These tumors may be solitary or multiple and occur in hereditary multiple exostoses syndrome. The conjunction of this lesion with peroneal nerve palsy has been exceptionally reported for children, usually linked to hereditary multiple exostoses syndrome. Most peroneal nerve trauma occurs at the fibular head, where the common nerve has not yet divided into its deep and superficial peroneal nerve and where most peroneal nerve lesions, therefore, involve both branches, although motor deficits are more frequently involved than sensory ones. Surgical treatment should not be delayed because neurological improvement may be achieved if surgery is performed before severe neurological deficits become irreversible.
The fibular nerve is frequently involved in cases of lesions or compression in the lower limb.1 It can be damaged due to direct injuries, fibular fractures, neuropathies, cysts from the tibiofibular joint, entrapments, and tumor.2,3 The most vulnerable point of injury to the peroneal nerve is the head of the fibular bone.3 Few cases have been reported on peroneal nerve compression by a benign bone growth in this area.2-7
This article describes a case of a child with an osteochondroma of the peroneal head causing peroneal nerve palsy.
An 11-year-old boy presented with tenderness at the right fibular head and foot drop of 3 months duration. He reported no history of trauma or previous neurological disease. Physical examination disclosed multiple bony exostoses overlying the ribs, knees, and ankles bilaterally. In particular, a large exostoses was palpated at the right fibular head. Tinels sign was positive with percussion to this area. Neurological examination revealed paresis of the tibialis anterior, lateral peroneal, and extensor digitorum muscles with a muscle strength grade of 2. No sensory loss was present in the affected leg.
Electrophysiological studies confirmed denervation of the muscles supplied by the right peroneal nerve, which suggested impairment of this nerve at the level of the fibular head. Radiological examination showed a bone prominence in the head of the right fibula (Figure 1). Biopsy confirmed the diagnosis of osteochondroma.
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Figure 1: Radiograph of the right knee showing an osteochondroma of the fibular head (A, B).
The patient underwent surgical decompression of the right peroneal nerve. A large exostosis of the fibular head, compressing and displacing the peroneal nerve, was observed intraoperatively (Figure 2). The bone lesion was removed (Figure 3).
Postoperatively, nerve function improved. Three months postoperatively, the patient had almost full recovery of the preoperative deficit. At 36-month follow-up, he had made a complete recovery, and no evidence of recurrence was seen.
The peroneal nerve is located behind the bony prominence of the fibular neck. It is superficial and covered primarily by subcutaneous tissue and skin.3 This anatomic course and the increased number of fascicles in this area make the nerve extremely vulnerable to injury. Although injury secondary to a fracture, dislocation, surgical procedure, or application of skeletal traction or a tight cast are the major causes of peroneal palsy, nontraumatic lesions also trigger peroneal nerve neuropathy and include mononeuritis, idiopathic peroneal palsy, intrinsic and extrinsic nerve tumors, extraneural compression by a synovial cyst, ganglion cyst, soft tissue tumor, and osseous mass.8
Peroneal mononeuropathy in children is uncommon. John et al9 identified 15 patients from >1100 patients studied by electromyography. In 1 of these patients, neuropathy was caused by exostoses at the fibular head. In another series of 103 patients with peroneal mononeuropathy, in over one-half of 7 patients younger than 18 years, neuropathy was the result of trauma.10
Osteochondroma is a benign tumor consisting of projecting bone (exostosis) capped by cartilage. These tumors may be solitary or multiple. Multiple tumors occur in hereditary multiple exostoses syndrome, an autosomic dominant disorder characterized by the formation of multiple bone prominences and developing from the epiphysis. The exostosis begins to develop in childhood and continues to grow until puberty.
Osteochondroma is usually asymptomatic and detected as an incidental finding on radiography.6,7 It is considered the most common of all bone tumors.11 Complications are directly related to tumor size and site and can be extrinsic, intrinsic, or mechanical in origin. Extrinsic complications of osteochondroma, due to its mass effect on adjacent tissues, can be subdivided depending on the tissue involved.
Nerve compression caused by this lesion is extremely rare, present in <1% of all cases and usually linked to hereditary multiple exostoses syndrome.12 Few cases of compression of the peroneal nerve by cartilaginous exostosis have been reported in the literature.3,5-7
In a study by Vanhoenacker et al,13 a serial evaluation of 489 exostoses in hereditary multiple exostoses syndrome demonstrated no nerve compression. This study estimated that the fibular bone can be involved in 8.2% of exostoses cases. Kim and Kline3 reported 302 cases of peroneal nerve injuries and described only 1 patient who presented with bilateral peroneal compression by exostosis of the head of the fibula.
Most peroneal nerve trauma occurs at the fibular head, where the common nerve has not yet divided into its deep and superficial peroneal nerve and where most peroneal nerve lesions, therefore, involve both branches; although motor deficits are more frequently involved than sensory ones. This finding may be explained by the arrangement of the fascicles inside of the common peroneal nerve. The motor fascicles run more medially, whereas the sensorial fascicles are located laterally.14 The exostosis grows from inside to outside, thus compressing the motor fibers earlier.
The general surgical indications for benign bony growths are cosmetic defect, exostosis in a location at risk of repetitive trauma, increased risk of the exostosis fracture,7 neurological involvement, impairment of articular range of motion, and suspicion of malignancy.4 In the fibular head region, the peroneal nerve is at risk for repetitive trauma, and motor weakness is the result of compression.
- Dawson DM. Entrapment Neuropathies. 2nd ed. Boston, MA: Little, Brown; 1990.
- Levin KH, Wilbourn AJ, Jones HR Jr. Childhood peroneal neuropathy from bone tumors. Pediatr Neurol. 1991; 7(4):308-309.
- Kim DH, Kline DG. Management and results of peroneal nerve lesions. Neurosurgery. 1996; 39(2):312-319.
- Cardelia JM, Dormans JP, Drummond DS, Davidson RS, Duhaime C, Sutton L. Proximal fibular osteochondroma with associated peroneal nerve palsy: a review of six cases. J Pediatr Orthop. 1995; 15(5):574-577.
- Piton C, Fabre T, Lasseur E, André D, Geneste M, Durandeau A. Common fibular nerve lesions. Etiology and treatment. Apropos of 146 cases with surgical treatment [in French]. Rev Chir Orthop Reparatrice Appar Mot. 1997; 83(6):515-521.
- Rinaldi E. Peroneal paralysis due exostosis of the fibula. Report of 2 cases. Ital J Orthop Traumatol. 1983; 9(2):259-262.
- Theodorou SD, Karamitsos S, Tsouparopoulos D, Hatzipavlou AG. Rare complications of exostosis. Fractures and injury to the common peroneal nerve. Acta Orthop Belg. 1978; 44(4):496-505.
- Salter RB. Textbook of Disorders and Injuries of the Musculoskeletal System. 2nd ed. Baltimore, MD: William & Wilkins; 1983.
- John HR JR, Gross PT, Gianturco L, Buchhalter J. Peroneal nerve palsy in children. Muscle Nerve. 1987; (10):664.
- Katirji MB, Wilbourn AJ. Common peroneal mononeuropathy: a clinical and electrophysiologic study of 116 lesions. Neurology. 1988; 38(11):1723-1728.
- Wicklund CL, Pauli RM, Johnston D, Hecht JT. Natural history study of hereditary multiple exostoses. Am J Med Genet. 1995; 55(1):43-46.
- Paik NJ, Han TR, Lim SJ. Multiple peripheral nerve compressions related to malignantly transformed hereditary multiple exostoses. Muscle Nerve. 2000; 23(8):1290-1294.
- Vanhoenacker FM, Van Hul W, Wuyts W, Willems PJ, De Schepper AM. Hereditary multiple exostoses: from genetics to clinical syndrome and complications. Eur J Radiol. 2001; 40(3):208-217.
- Urushidani H. The funicular pattern of sciatic nerve in Japanese adults [in Japanese]. Nippon Geka Hokan. 1974; 43(4):254-275.
Drs Mnif, Koubaa, Zrig, Zammel, and Abid are from the Department of Orthopedic Surgery, Hospital Monastir, Tunisia.
Drs Mnif, Koubaa, Zrig, Zammel, and Abid have no relevant financial relationships to disclose.
Correspondence should be addressed to: Hichem Mnif, MD, Department of Orthopedics, Hospital Monastir, Road 1 June, Monastir, Tunisia.