Use of Endoprosthetic Diaphyseal Replacement: A Novel Approach to Management of Extensive Metastatic Tumor of the Midshaft Radius Simon Macmull, MBBS, MRCS, Kishan Gokaraju, BMedSci, MBChB, MRCS, Jonathan Miles, MBChB, FRCS (orth), Gordon W. Blunn, PhD, Steve R. Cannon, FRCS, MCh (orth), and Tim W. Briggs, MD (res), MCh (orth), FRCS Abstract: We report the first use of an endoprosthetic diaphyseal replacement after the excision of a midshaft radial tumor. We present a rare case of a solitary midshaft radial metastasis in a 72-year-old gentleman who was treated 8 years earlier for primary renal cell carcinoma by radical nephrectomy. Follow-up for this patient was 25 months after implant insertion and at the latest review was pain-free. Functional scores for the elbow (using the Mayo Elbow Performance Score) and the wrist (using the Mayo Wrist Score) were 80 and 60, respectively, both out of 100. Use of a midshaft radial endoprosthesis provides a good functional outcome and symptom relief after extensive tumor resection, with regard to functional outcome and symptom relief. Key Words: metastatic, diaphyseal, endoprosthesis, intercalary (Tech Hand Surg 2010;14: 183--186) CASE REPORT A right-handed 70-year-old man was referred to our specialist bone tumor unit for treatment of a left midshaft radius pathologic fracture secondary to renal metastatic disease. The patient had been diagnosed with renal cell carcinoma and had undergone a nephrectomy 8 years earlier. The patient presented with a short history of severe pain in his left forearm, but no history of trauma. Examination revealed painful restricted movements of both the elbow and wrist with localized tenderness in the mid-forearm. Radio- graphs demonstrated a large osteolytic lesion in the midshaft of the left radius, measuring approximately 6  2 cm, with evidence of a pathologic fracture (Fig. 1). Pain and immobility of the limb restricted any form of preoperative functional scoring. A radioisotope bone scan and staging computed tomography revealed this to be a solitary metastatic deposit. Magnetic resonance imaging confirmed that significant local neurovascular structures were not involved (Fig. 2). The lesion was embolized for both pain relief and to aid excision of the tumor. We decided to excise the lesion and reconstruct the radius with a custom-made diaphyseal endoprosthesis. Mea- surement x-rays were taken of the contralateral forearm as a template for accurate sizing of the prosthesis (Fig. 3). The tumor was accessed via the Henry approach to the radius, under tourniquet control. Flexor pollicus longus and flexor digitorum profundus were lifted off their origins to gain access the tumor. The major neurovascular structures were seen and protected throughout. However, it was very difficult to see the posterior interosseous nerve. Dissection was therefore close to the bone at the proximal radius. The tumor was excised and sent for histologic examination. The distal and proximal radiuses were curetted with imprints sent for the examination. Fibers of the muscles involved in the tumor were excised en bloc with the tumor to maintain clear margins. The stemmed titanium diaphyseal replacement with proximal and distal hydroxyapatite-coated collars was cemented in situ on separate segments and then connected and held with 2 bolts. The origins of flexor pollicus longus and flexor digitorum profundus were returned to their anatomic positions and allowed to scar down onto the prosthesis and surrounding soft tissues (Fig. 4). FIGURE 1. X-ray of the left forearm showing extensive destructive lytic lesion of the radius. Copyright r 2010 by Lippincott Williams & Wilkins From the Royal National Orthopaedic Hospital, Middlesex, UK. Address correspondence and reprint requests to Simon Macmull, MBBS, MRCS, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex HA7 4LP, United Kingdom. E-mail: simonmacmull@hotmail.com. TECHNIQUE Techniques in Hand & Upper Extremity Surgery  Volume 14, Number 3, September 2010 www.techhandsurg.com | 183