Bone loss related to primary or metastatic cancer lesions of the shoulder’s proximal humerus is a challenging problem for orthopaedic surgeons. Many methods of surgical repair can result in poor function related to the loss of the rotator cuff and deltoid function. In a recent study, UAB surgeons found that use of a low-profile locking plate and bone cement can boost the outcome when treating patients with these pathological or impending pathological humeral fractures.
Between December 2003 and December 2007, Herrick Siegel, MD, Associate Professor of Orthopaedic Surgery, and his UAB associates conducted a study of this procedure using bone cement on 32 oncology patients who had pathological fractures of the proximal humerus. After 18 months of following these patients, functional and radiological assessments showed no evidence of failure in the surgical repair. 22 of the study patients were employed prior to their surgery, and they all were able to return to work without restrictions.
“We found that augmenting use of the locking plate with bone cement may reduce the time in the hospital, compared with joint replacement, and it often results in better function of the affected shoulder,” Siegel says.
Pathological fractures typically occur in a weakened bone and are often the result of malignant tumors. Biologic and mechanical obstacles such as chemotherapy, radiation therapy, bone grafts, and long pathological segments of bone are present in oncology patients, which make osteosynthesis more difficult.
The humerus is the second most common site for long bone tumors, second only to the femur. Historically, pathologic humerus fractures have been treated without surgery, using casts, splints, or braces in conjunction with radiotherapy. Functional outcome for these patients was poor because use of the arm was greatly limited. As a result, surgical techniques were developed to stabilize the fractures.
In the proximal humerus, the bone is subject to extreme bending and rotational forces from its various muscle insertions. Traditional surgical techniques for treating these injuries required that bone cement be placed in the affected bone initially, followed by screws placed either outside the cement or in holes drilled into it. “This surgical method can cause fragmentation and weakening of the bone-cement interface, and using high-profile thick plates can irritate soft tissues,” Siegel says. “It is also more technically challenging and can result in excessive surgical time and early failure.”
In the revised procedure used in the study, the surgeon uses a low-profile locking plate that allows for multidirectional placement of the locking screws. The screws are evenly distributed throughout the humeral head. In the bone cavity, locking screws are placed to form a lattice for cementing and the cavity is then filled with bone cement. “This results in a more stable fixation of the humerus and reinforces the bone-cement construction,” Siegel says.
In recent years, resection of the humerus with endoprosthetic reconstruction has gained popularity in the management of destructive lesions in the proximal humerus, but use of the proximal humerus plate and cement augmentation allows more of these patients to be treated successfully with potential for a better functional outcome. “Introduction of a locking plate into orthopaedic oncology has made a significant impact,” Siegel says. “Many oncology patients are treated with chemotherapy, radiation, or both prior to surgery. The resulting immune and bone marrow suppression often places these patients at an increased risk of infection, hematoma, and wound complications. This new method of repairing the fracture limits surgical time, exposure and blood loss, which is better for the patient.”
Siegel adds that the proximal humerus appears to be a suitable site for aggressive treatment without compromising the stability or function of the shoulder joint. “With the use of this technique, pathological fractures that once were thought to be unsalvageable may now be treated successfully,” he says.