RARE ABNORMALITIES OF THE SCAPHOID IN ASSOCIATION WITH CONGENITAL RADIAL RAY DEFECTS OF THE HAND: A REPORT OF TWO CASES R. W. PARKINSON, J. NOBLE, R. S. BALE and A. J. FREEMONT From Hope Hospital, Salford and the University of Manchester Medical School There is a well-recognised associationbetweencongenital hypoplasia or absence of the carpal scaphoid and retardation in the development of the first metacarpal, thumb and thenar muscles (Davidson, 1962).Idiopathic avascular necrosis of the scaphoid (sometimes called Preiser’s disease) is extremely rare and has only been reported sporadically (Ekerot and Eiken, 1980; Allen, 1983; Bray and McCarrol, 1984; Ferlic and Morrin 1989).Congenital bipartite scaphoid is also uncommon but is well reported (Boyes, 1970; Kelikian, 1974; Sherbok and Grogan, 1980; Richards et al., 1987). We report two patients with radial ray defects, one of whom has idiopathic avascular necrosis of the scaphoid and the other a congenital bipartite scaphoid. We believe these associations have not been reported previously in the English literature. We discuss their clinical signifi- cance. Case reports case 1 A 20-year-old shop assistant presented with a six-week history of pain in the right wrist, though she had experienced occasional aching in the wrist for the previous two years. There was no definite history of injury. There is a family history of myotonic dystrophy, but our patient has no clinical features of this condition. On examination she had hypoplastic thumbs and wasting of the thenar musculature in both hands (Fig, 1). She was tender over the right scaphoid and had a weak, painful grip. All movements of the wrist were limited and painful. Neurological and general examination of the patient was otherwise normal. Radiographs of the right wrist and hand showed increased density, fragmentation and collapse of the scaphoid, indicating longstanding avascular necrosis. Shealso had a hypoplastic first metacarpal and there was 1 mm of negative ulnar variance (Fig. 2). Radiographs of the left wrist showed a hypoplastic but normal density scaphoid, a hypoplastic first metacarpal and 2 mm of negative ulnar variance (Fig. 3). A TcHDP bone scan of both wrists showed abnormal isotope uptake in the region of the right scaphoid, consistent with avascular necrosis.The bone scanof the left wrist was normal. She was treated in a scaphoid plaster for eight weeks, Fig. 1 Case 1. Right hand showing the hypoplastic thumb and wasting of the thenar muscles. over the following year with increasing pain in the right wrist. after which she returned to work but continued to complain of a weak painful grip. Her symptoms worsened The scaphoidwas therefore explored from the anterior approach and the fragmented bone excisedpiecemeal. It was our original intention to put in a silastic scaphoid prosthesis, but it was not possible to insert even the smallest silastic spacer because the spacewas too small. In addition, there were marked degenerativechangesin the radio-scaphoid joint which further excluded the use of a scaphoid implant. The patient was therefore left with a simple excision arthroplasty. Histology of the excised scaphoid showed necrosis of the entire bone, followed by new bone formation centrally, confirming the diagnosis of avascular necrosis (Fig. 4). At follow-up nine months after operation, the patient was virtually free of pain and had returned to work without difficulty. 208 THE JOURNAL OF HAND SURGERY