Late-onset implant-related neuropathy: Three years after proximal humeral fracture

There are currently no reports of implant-related neuropathy associated with humeral proximal fracture surgery. Herein, we report a case of implant-related late-onset neuropathy that developed 3 years after proximal humeral fracture surgery. A 51-year-old man underwent minimally invasive plate osteosynthesis for a left proximal humeral fracture 3 years prior. Left upper limb pain and reduced angle of elevation of the shoulder were recognized 1 month before the outpatient consultation. Numbness was noted on the ulnar side of the hand, and radiating pain to the ulnar nerve region was noted during shoulder abduction and compression of the medial side of the upper arm. Computed tomography revealed close proximity of the neurovascular bundle to the locking screw along with muscle atrophy around the shoulder. Hence, the patient was diagnosed with neuropathy. After implant removal, the pain in the ulnar nerve region improved, and the upper arm could be elevated. In our case, the cause of muscle atrophy was axillary nerve manipulation and cervical myelopathy caused by the operation. When late-onset neuropathy occurs, implant-related neuropathy with muscle atrophy should be considered.