7 to treat mallet fracture and evaluate its efficiency. scientific study MATERIALS AND METHODS Between 2004 and 2009, 38 mallet fractures that involved one third or more of the articular surface were treated using extension block technique by five physicians. (Figure 1) Figure 1 Lateral radiography of the finger in the preoperative. Patients included 24 men and 14 women with a mean age of 34,3 years (range, 19-46 years). In 10 cases the finger affected was the fifth, in 16 cases, the forth, in 12 cases, the third. Twenty four injuries occurred in the dominant hand. All injuries were closed and in four cases showed subluxation of the distal phalanx. The mean time from fracture to operation was 1,7 days (range 0-4 days). Clinical results were assessed using the criteria published by Crawford.

8 Radiographs were taken of all cases after surgery. (Figure 2a and 2b). Figure 2 (A) Postoperative AP radiography. (B) Postoperative lateral radiography. On radiographs were evaluated: union, malunion, space, inclination, degenerative changes, subluxation and deformity. The values of the passive range of movement of the joint IFD were measured with a goniometer. Patients with an average 18 months (12-36 months) were invited to participate in a telephone assessment of the long term results of the treatment SURGICAL TECHNIQUE The operation is performed under digital block anesthesia. DIP joints are passively flexed so that the displaced fragment moves to its original position because of to maintain continuity periosteal. A 0.035″ (0.9 mm) or 0.045″ (1.

4 mm) K wire is inserted through the extensor tendon at a 45 degree angle into the head of the middle phalanx along the dorsal edge of the fragment under the surveillance of C-arm. (Figure 3) Figure 3 Show that clinically K wire inserted techniques. The distal phalanx is extended to 0 degree. A second K wire is inserted to transfixed the DIP joint in to the middle phalanx to maintain reduction. Active motion of the PIP and MP joints is started immediately after the surgery. Splinting and antibiotics were not used. The follow up visit was conducted ten days after the surgery to evaluate the site of the pin. At the end of the sixth week, K wires were removed after radiographic control of the healing and a night splint was used for two weeks. The patient was encouraged to do active and passive exercises of range of motion (ROM) immediately with the DIP joint.

RESULTS In the radiographic assesment, union was obtained in all patients. No malunion or subluxation were found in any patient. Knitting The anatomical union was obtained in 24 cases; in 10 cases there was a gap of less than 2 mm, and in four cases, the gap was of more than GSK-3 2 mm. (Figure 4) Figure 4 The lateral radiograph shows union. The DIP joint had an average extension lag of two (0-7) degrees and the final flexion was 70o on average (45o-80o). There were no cases of infection along the pin tract, instability or nail bed injury.