We present a prospective study outlining the management of clenched fist 'fight bite' injuries. Over a 4-year period all patients with such injuries had surgical exploration with further débridements as necessary. For metacarpophalangeal joint injuries, a midline tendon-splitting approach was used. For proximal interphalangeal joint injuries, an approach was made between the lateral band and central slip of the extensor mechanism. A total of 147 patients with 159 joint injuries were treated, with 130 metacarpophalangeal joint and 29 proximal interphalangeal joint injuries. The joint was penetrated in 96% of joints overall. The number of débridements ranged from two to eight. Twenty patients defaulted within 1 week of surgery and were not included in the analysis of the results. All patients with metacarpophalangeal joint injury had satisfactory or good outcomes. A total of 42% of patients with proximal interphalangeal joint injuries had poor results, four requiring amputation and one a fusion. The tendon-splitting approach to the metacarpophalangeal joint allows excellent access and avoids damage to the sagittal bands and consequent instability of the extensor mechanism.