Article
Ulnar neuropathy at the elbow in 413 Japanese patients: an assessment of pathological elbow lesions and neurological severity
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Published: | February 6, 2020 |
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Objectives/Interrogation: Pathological lesions of the elbow are often complicated by ulnar neuropathy at the elbow (UNE); however, detailed pathological and neurological features of these lesions remain unidentified. We investigated the elbow pathology and neurological severity of UNE in Japanese patients.
Methods: We retrospectively examined the medical records of 457 patients aged 15 years or more who were diagnosed with UNE and surgically treated by certified hand surgeons between 2000 and 2012 at six participating institutions. UNE of eligible patients were diagnosed by physical findings and nerve conduction studies. Elbows were analyzed for age, gender, occupation, elbow pathology, entrapment site of the ulnar nerve, and severity of nerve palsy.
Results: A total of 413 UNE elbows in 398 patients with a median age of 63 years (range: 15-87) were included. UNE elbows were predominantly male (69%). Of 310 elbows, 75% had 1 or more lesions: single lesion, 238 elbows (77%); 2 or more lesions, 72 elbows (23%). Common lesions were as follows: primary elbow osteoarthritis (EOA), 55% of elbows; medial elbow ganglion, 9%; cubitus valgus, 7%; dislocation of the ulnar nerve, 6%; prior elbow trauma, 3%; cubitus varus, 2%. Medial elbow ganglion and cubitus valgus or varus were generally associated with EOA (91% and 67%, respectively). UNE with primary EOA exhibited older age, higher prevalence of manual laborers and severe ulnar nerve palsy, and longer symptom duration compared to those with no lesion. Common entrapment sites were: cubital tunnel, 86%; medial epicondyle, 5%; deep flexor pronator aponeurosis, 4%; medial intermuscular septum, 2%. Incidences of primary or secondary EOA and severe motor weakness (McGowan grade III) were 62.2% and 47.2% in this study, respectively; in contrast, 9.5 to 19.7% and 15.0 to 26.4% have been previously reported for the Caucasian population, respectively.
Conclusions: This study showed that 75% of UNE had isolated or combined pathological lesions, and 85 to 90 % of UNE had an entrapment site at the cubital tunnel regardless of the lesion. In Japanese patients, EOA was highly associated with UNE, and clinical features of UNE with EOA differed from UNE with no lesion. In contrast to Caucasians, the UAE of Japanese patients showed high incidences of EOA and severe ulnar nerve palsy.