A 46-year-old man injured his ring finger and developed a mallet deformity. Radiographs showed a mallet finger fracture through an osteolytic lesion of the distal phalanx. Magnetic resonance imaging showed low intensity on T1-weighted imaging and high intensity on T2-weighted imaging, which suggested the clinical diagnosis of enchondroma. The bone tumor was excised, and osteosynthesis was performed using Ishiguro's extension block pinning, and a flexion block pin was added to prevent flexor tendon avulsion fracture through the enchondroma, followed by an autologous iliac cancellous bone graft. One year after surgery, the patient had no pain or extension lag of the affected ring finger, and his quickDASH score was 0 points. Radiographs showed no recurrence and minimal arthritic change of the distal interphalangeal joint. One-stage treatment of a mallet finger fracture through an enchondroma using Ishiguro's method was effective.

We report a case of carpal tunnel syndrome and trigger wrist caused by localized amyloidosis. A 37-year-old man, who worked as a manufacturer, presented with a 5-month history of tingling sensation in the three radial fingers of the left hand and a painful click at the volar aspect of the wrist during digital motion. We divided the transverse carpal ligament and detected diffuse tenosynovitis that was especially severe around the flexor digitorum profundus tendons. Histological findings led to a diagnosis of amyloidosis. Localized amyloidosis could thus be a cause of trigger wrist. Systemic amyloidosis may develop in patients with localized amyloidosis; therefore, patients with trigger wrist caused by flexor tenosynovitis should be investigated for the existence of localized amyloidosis, with biopsy of the flexor tenosynovium.

Intramedullary fixation for distal radius fractures was free from tendinous complications such as tenosynovitis and tendon ruptures around the implant, which are frequently caused by volar locking plate fixation. However, this less invasive technique could not avoid common complications such as trigger finger and carpal tunnel syndrome associated with distal radius fractures.

We report a case of closed rupture of the flexor tendons of the little finger caused by calcium pyrophosphate dihydrate crystal deposition disease of the pisotriquetrum joint. The patient could not flex the little finger and did not have wrist pain. Plain radiographs of the affected wrist joint showed severe arthritic changes of the pisotriquetrum joint and calcification around the joint. At operation, the pisotriquetrum joint capsule was ruptured and involved the flexor tendon of the little finger. The distal stump of the flexor tendon was transferred to the flexor tendon of the ring finger, and the pisiform was resected. Histological examination with polarized light microscopy revealed crystals showing weakly positive birefringence in the calcification.

The findings of this study indicate that intramedullary implants for dorsally displaced extra-articular or simple intraarticular distal radius fractures may offer good radiological and functional outcomes without hardware irritation in elderly patients. Distal radius fractures with an osteoporotic, large medullary canal should be stabilized by implants of an appropriate size.