Metastatic disease to the upper extremity is a relatively common occurrence. Although the upper extremity is typically non-weight bearing, its role in activities of daily living, including bathing, toileting, and eating, is critical to a patient’s quality of life. Furthermore, because metastatic disease in the skeleton often additionally involves the lower extremities, competent upper extremities are needed for patients who rely on crutches or walkers for assistance with ambulation. For this reason, it may be prudent to radiographically assess asymptomatic upper extremity long bones in patients with symptomatic lower extremity metastatic disease.

The humerus is the second most frequently involved site in the appendicular skeleton following the femur.¹ As with other skeletal sites, the common histologic subtypes present in the upper extremity are lung, breast, prostate, kidney, and thyroid carcinoma. Of these, breast and renal carcinomas have been reported to have the highest predilection for humeral metastases,² whereas lung carcinoma has a predilection for metastasizing to the hand. A multidisciplinary team is imperative in treating this patient population. As discussed in a 2023 study, the surgical care for patients with bone metastases must be a collaborative effort, with medical and radiation oncologists sharing in the decision making.³ End-of-life discussions often are required to determine whether surgery to treat a patient with symptomatic metastasis is appropriate. The role of the orthopaedic surgeon caring for these patients should be carefully aligned with that of the other caregivers to provide thoughtful and appropriate care. A guide for decision making in the management of bone metastasis to the upper extremity is presented in Figure 1. The algorithm is predicated on the presence of either known metastatic cancer or a proximate history of cancer.⁴ If, during the initial presentation, no documented history of cancer can be substantiated, the patient must undergo workup to demonstrate the objective presence of malignancy and metastasis.⁵

Next, the presence or absence of a fracture is determined. If the patient has sustained a stable fracture with minimal bone loss or the patient has a short life span or poor performance status, the overall treatment recommendation would be immobilization and radiation as needed.⁶ Conversely, in a patient who has sustained an unstable fracture, with significant structural bone loss and if the patient’s life span and performance status are amenable to surgery, surgery can be beneficial for improving function and relieving pain. The goal is to provide durable stability and to ease symptoms with one procedure. A similar approach is implemented in patients with impending fractures (Figure 1).

The humerus is the site of most metastases of the upper extremity.¹ A logical approach to surgical management is site specific within the bone, with different considerations for the proximal humerus, humeral diaphysis, and distal humerus. Figure 2 presents an algorithm for surgical management of metastatic disease in the humerus.

Small symptomatic proximal humeral lesions that occupy less than 50% of the bone stock and preserve the articular surface can be successfully managed with curettage and polymethyl methacrylate (PMMA) bone cement packing with or without application of a plate and screws (Figure 2). The addition of internal fixation in this location is based on the amount of bone loss and the bone’s structural stability after curettage (Figure 3).

According to a 2020 study, when the lesion is large and/or the articular surface is lost, endoprosthetic replacement is recommended.⁷ If the greater and lesser tuberosities are intact, a standard cemented humeral hemiarthroplasty can be performed. If the tuberosities are effaced or deficient, a proximal humeral segmental resection is recommended with a proximal humeral endoprosthetic reconstruction (Figure 4). The standard endoprosthetic replacement provides a more favorable functional result where possible, because a proximal humeral replacement detaches soft tissues and can present problems of glenohumeral instability. In some patients, the deltoid insertion can be spared when the rotator cuff attachment site is lost. Reverse total shoulder arthroplasty is being used more frequently for metastatic disease of the proximal humerus. Recent studies suggest that the reverse arthroplasty may offer functional benefits over that of a standard hemiarthroplasty or total shoulder arthroplasty, but this remains an area of active investigation.^8,9,10 Some success has also been reported with allograft-prosthetic composites in the setting of proximal humerus pathologic fractures.^9,11