ABSTRACT
Locked thumb metacarpophalangeal (MCP) joint has been known as a relatively rare condition. We present a case of a 25-year-old male presented with a traumatic locked thumb MCP joint of the right hand. Clinical presentation showed the joint was in a hyperextention position and resistant to active flexion and extension. The radial sesamoid was distally displaced on X-ray film and entrapped into the joint on CT scan. The mechanism of the locked MCP joint was thought as a "pull-hook lock" between the pointed proximal edge of the sesamoid and the deformed volar groove on the cartilaginous surface of the metacarpal head. Surgical treatment included partially releasing the insertion of the abductor pollicis brevis (APB) and flexor pollicis brevis (FPB) muscles to move the entrapped radial sesamoid, and resurfacing the deformed metacarpal head.
ABSTRACT
INTRODUCTION AND IMPORTANCE: Anterior column plate combined with posterior column screws have been effectively used for treatment of displaced transverse acetabular fractures. This article presents the use of 3D-printed technology for customising a guide template to appropriately place posterior column screw. CASE PRESENTATION: A 50-year-old female suffered displaced juxtatectal fracture of the right acetabulum. A personalised guide for antegrade posterior column screw placement was designed based on the data of her pelvic CT-scan. This guide and a prototype of her right acetabulum - created by mirroring the intact left acetabulum - were 3D-printed for preoperative evaluation and pre-contouring of reconstruction plate. Modified Stoppa approach and additional lateral window were used for direct reduction, anterior column plate and posterior column lag screw fixation. Post-operative CT-scan showed good reduction and nearly ideal screw position. CLINICAL DISCUSSION: Anterior column plate and antegrade posterior column screw could provide joint stability and early mobilisation for displaced transverse acetabular fractures. However, determination of optimal entry point, direction and length for screw insertion is still technically demanding. The 3-D reconstruction images of hemipelvic specimen allowed us to identify the safe bone corridor, design a drill guide to put the proper guide pin and conduct preoperative trial. All those resulted in appropriate real screw fixation with reduction of soft tissue damage, X-ray exposure and time of operation. CONCLUSION: The use of 3D-printed personalised guide for posterior column screw fixation is a promising alternative option for treatment of displaced transverse acetabular fracture where 3D-navigation system is not available.