Orthopedic Expert Witness Opines on Neuropathy Resulting From Incorrectly Fitted Humeral Head Prosthesis

This case involves a fifty-two-year-old male who sustained a work-related musculoskeletal injury. The patient presented to an orthopedic surgeon with bilateral shoulder pain. The surgeon conducted a physical examination and reviewed the patient’s imaging studies. After this initial consultation with the patient, a diagnosis of osteoarthritis of the shoulders was made and a neck abnormality was queried. Medical management was attempted but unsuccessful. The patient returned to the orthopedic surgeon with the same complaints, he recommended bilateral total shoulder arthroplasty. They decided to have the right shoulder corrected first followed by the left three months later. The medical records show that whilst the treating surgeon did inform the patient of some of the risks of the procedure such as wear and tear, loosening and infection he was not informed of the potential risk of nerve damage before consenting to the surgery. Post-operatively the patient suffered from aching pain, decreased range of motion, and numbness of the right forearm. The surgeon suggested that the pain may be the result of the nerve block or pressure applied to the nerves during the procedure. He did not suggest that the manner in which he performed the surgery could have been the cause of the patient’s symptoms. The surgeon referred the patient to a physical therapist. Her symptoms continued despite physical therapy. She had very limited range of motion in the right shoulder and forearm. The physician decided to order an EMG to evaluate the arm for nerve damage. The electromyography (EMG) revealed denervation of the bicep which was suggestive of musculocutaneous neuropathy. She was found to have musculoskeletal neuritis. The orthopedic surgeon then decided to perform an arthroscopic manipulation in an attempt to increase range of motion. The patient repeatedly saw the original physician over the next couple of years with no resolution to the musculoskeletal neuritis. Finally, after continued treatment under the care of the original physician with no success, she sought a second opinion. The new orthopedic surgeon noted the humeral head prosthesis used in the original arthroplasty to be too big. Additionally, he noted the musculoskeletal nerve damage likely occurred when traction was applied. The patient’s only option at this point was to undergo a corrective arthroplasty surgery which she has declined fearing further surgical complications. The patient never recovered and was left with permanent physical impairment with a severely limited use of her right arm.

Question(s) For Expert Witness

1. What are the typical instances of musculoskeletal nerve injury in shoulder arthroplasty?

Expert Witness Response

Musculoskeletal nerve injury typically occurs as a result of traction and is most commonly seen after retraction-related traction injury in shoulder procedures; sometimes it can be directly injured at the time of biceps procedures or coracoid transfers. It is imperative during arthroplasty that the correct size prosthesis is selected to prevent injury to the patient. The humeral head is usually sized by a combination of pre-operative templating from radiographs and intraoperative evaluation of the size and dimensions of the resected head.