Joint distraction for ankle osteoarthritis

5 Safety

This section describes safety outcomes from the published literature that the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the interventional procedure overview.

5.1 Deep vein thrombosis distal to the knee was reported in 1 patient treated by ankle joint distraction in a randomised controlled trial (RCT) of 36 patients treated by fixed distraction (n=18) or distraction with motion (n=18); this was treated by anticoagulation therapy (no further details provided).

5.2 Infection at the pin sites was reported in 28% (16/57) of patients treated by ankle joint distraction in a case series of 57 patients; this was treated by antibiotics (no further details provided). Pin track infection was reported on 43 occasions in 53% (19/36) of patients in the RCT of 36 patients treated by fixed distraction or distraction with motion. All infections were initially treated with oral antibiotics; 4 persisted and the pins were removed. Two of the 4 infections were treated by 6 weeks of intravenous antibiotics because acute osteomyelitis was suspected. Superficial pin site infection was reported in 100% (23/23) of patients with complete data in a case series of 25 patients treated by ankle joint distraction; all infections resolved following a single course of antibiotics.

5.3 Numbness in the distribution of the medial calcaneal branch of the tibial nerve and in the deep peroneal distribution onto the great toe, after the frame was fitted, was reported in 22% (8/36) of patients in the RCT of 36 patients treated by fixed distraction or distraction with motion. When numbness occurred in the context of distraction exceeding 5 mm on X‑ray, the distraction was reduced to 5 mm; no other treatment was given. In 50% (4/8) of patients numbness resolved with the frame in place, 25% (2/8) resolved within 3 months after frame removal, and 25% (2/8) of patients were left with residual numbness.

5.4 Sudeck's atrophy (reflex sympathetic dystrophy) was reported in 2% (2/105) of patients treated by ankle joint distraction who were still in the study at 2‑year follow‑up, in a combined analysis of a case series of 75 patients treated by ankle joint distraction and the RCT of 36 patients treated by fixed ankle distraction or distraction with motion. Sudeck's atrophy was reported in 1 patient treated by ankle joint distraction in a case series of 22 patients; it was unclear if this was related to the procedure.

5.5 A broken pin through the forefoot, possibly caused by excessive strain during walking, was reported in 14% (8/57) of patients in the case series of 57 patients. Of these patients, 63% (5/8) had the broken pin removed and 38% (3/8) had the pin replaced; local infections were prevented or treated by antibiotics.

5.6 In addition to safety outcomes reported in the literature, specialist advisers are asked about anecdotal adverse events (events which they have heard about) and about theoretical adverse events (events which they think might possibly occur, even if they have never done so). For this procedure, specialist advisers listed the following anecdotal adverse events: stiffness or clawing of the toes, pain during distraction, and difficulty tolerating the frame. They considered that the following were theoretical adverse events: neurovascular injury, tendon injury, creation of deformity, risk of worsening symptoms, septic arthritis, avascular necrosis of the talus, fracture, joint stiffness, complex regional pain syndrome, and ongoing pain after the frame is removed.