Aims

Arthroplasty has become increasingly popular to treat end-stage ankle arthritis. Iatrogenic posterior neurovascular and tendinous injury have been described from saw cuts. However, it is hypothesized that posterior ankle structures could be damaged by inserting tibial guide pins too deeply and be a potential cause of residual hindfoot pain.

We carried out a prospective study over a period of 12 months to measure the exposure to radiation of the hands of a dedicated foot and ankle surgeon. A thermoluminescent dosimeter ring (TLD) was used to measure the cumulative dose of radiation. Fluoroscopy was used in operations on the foot and ankle. The total screening time was 3028 s, with a mean time per procedure of 37.4 s (0.6 to 197). This correlated positively with the number of procedures performed (r = 0.92, p < 0.001), and with the dose of radiation in both the left (r = 0.85, p = 0.0005) and right TLDs (r = 0.59, p = 0.419). There was no significant difference in the dose of radiation between the two hands (t-test, p = 0.62). The total dose to the right TLD over the 12 months was 2.4 millisieverts. This is a simple and convenient method for evaluating the exposure of a single surgeon to radiation. The radiation detected was well below the annual dose limit set by the International Commission on Radiological Protection

Supination-external rotation (SER) fractures of the ankle may present with a medial ligamentous injury that is not apparent on the initial radiographs. A cadaver gravity-stress view has been described, but the manual-stress view is considered to be the examination of choice for the diagnosis of medial injuries. We prospectively compared the efficacy of these two examinations.

We undertook both examinations in 29 patients with SER fractures. Of these, 16 (55%) were stress-positive, i.e. and had widening of the medial clear space of > 4 mm with a mean medial clear space of 6.09 mm (4.4 to 8.1) on gravity-stress and 5.81 mm (4.0 to 8.2) on manual-stress examination, and 13 patients (45%) were stress-negative with a mean medial clear space of 3.91 mm (3.3 to 5.1) and 3.61 mm (2.6 to 4.5) on examination of gravity- and manual-stress respectively. The mean absolute visual analgoue scale score for discomfort in the examination of gravity stress was 3.45 (1 to 6) and in the manual-stress procedure 6.14 (3 to 10).

We have shown that examination of gravity-stress is as reliable and perceived as more comfortable than that of manual stress. We recommend using it as the initial diagnostic screening examination for the detection of occult medial ligamentous injuries in SER fractures of the ankle.