Multicenter, retrospective comparison of implant survival, complications and cost between plate and screw and intramedullary nail fixation for metastatic lesions of the diaphyseal humerus.

Background: The humerus is a common site of metastatic disease that can be fixated with either plate and screw or intramedullary nail (IMN) constructs. A multicenter retrospective comparison study was undertaken to compare implant survival, complication rate and cost between the two constructs. No prior studies have included a cost comparison.

Methods: Databases of two academic practices were queried retrospectively to identify patients with metastases of the humerus. Inclusion criteria were a lesion in the proximal metaphysis to distal diaphysis and amenable to both implant options with available cost data. Follow-up was at least 6 months barring death or discharge to hospice sooner. Demographic, clinical and outcome data was recorded. Costs were estimated based on contract pricing. Operating room (OR) costs were estimated using per minute OR costs proposed by other investigators.

Results: One hundred and one humeri in 96 patients were included (72 plates and 29 nails). The most common malignancies were renal cell, myeloma and lung. Half presented with a displaced fracture. Demographics were similar in both groups. Lesions were larger in the plate group. Surgical times were longer in the plate group, 146 vs. 75 min, P<0.001. Estimated blood loss (EBL) was higher in the plate group, 510 vs. 221 mL, P<0.001. A trend toward increased failure was seen in the plate group, 12.5% vs. 0% (P=0.056). The most common complications in the plate group were pain, stiffness and swelling compared to pain, refracture and PE in the nail group. Local disease progression was equivalent. Implant costs were higher in the IMN group ($2,753 vs. $1,553, P<0.001), while OR costs were lower ($2,349 vs. $4,395, P<0.001). Overall cost of implantation was lower in the IMN group ($5,102 vs. $5,949, P=0.005).

Conclusions: IMN of metastases of the humerus offers a faster, potentially more durable construct with lower blood loss, faster OR times and decreased cost of implantation.