Subtalar instability has been recognized as a cause of ankle symptoms. The purpose of this anatomic study is to determine the ligament damage required to produce subtalar instability, and to define a radiographic technique to demonstrate it. Ten fresh adult cadaver ankles were dissected. Selective sectioning of the calcaneofibular ligament, capsule, and interosseous ligaments of the subtalar joint were done. Radiographic documentation of subtalar opening was recorded, using a lateral and Brodan's view. Sectioning of the calcaneofibular ligament alone produced a 5-mm opening of the subtalar joint. When combined with sectioning of the interosseous ligament, a 7-mm opening was produced. This was reproduced with a plantar flexion-supination load to the foot. Instability of the ankle joint (talar tilting) was produced only when loading caused additional tearing of the anterior talofibular ligament. This study suggests that surgical repairs to correct lateral ankle instability should include repair or substitution of the calcaneofibular ligament if subtalar instability is a consideration.

The average general orthopaedic surgeon examines and treats a considerable number of acute lateral ankle ligament sprains in a busy office practice. A cursory review of recent articles published on this subject will present a confusing picture regarding diagnosis and treatment of Grade III injuries. An air of controversy surrounds the interpretation of diagnostic x-rays, and the management of these common ankle problems. This review article is presented to summarize current thoughts on the anatomy, biomechanics, diagnosis, and treatment of acute lateral ankle ligament sprains.

A modification of internal fixation compression arthrodesis for ankle fusion is described using two 6.5-mm cancellous bone screws and a lateral T plate. Using this technique, 20 consecutive arthrodeses by one surgeon were reviewed. Solid union was attained in 19 of 20 patients (95%). Average follow-up was 18 months (range 6-59 months). Time to obtain solid arthrodeses averaged 18 weeks. In 11 patients who returned for follow-up, clinical grading using the Mazur scale score averaged 70 of 90 points. Diagnoses included posttraumatic degenerative arthritis, failed ankle arthrodesis and rheumatoid arthritis (2 each), failed ankle arthroplasty, and post-tuberculous arthritis (1 each). Complications included one malunion and one asymptomatic screw malposition. All patients attaining union were pleased with the procedure.

Nineteen heels in 19 patients underwent a lateral decompression for hindfoot pain secondary to a malunited os calcis fracture with subtalar intra-articular involvement. The operative procedure consisted of a lateral calcaneal bony prominence removal (ostectomy) and sural nerve release or transection. In addition, the peroneal tendons were released, relocated, and lengthened as necessary, with repair or reconstruction of their retinaculum. Eight patients (group I) had previously undergone a late subtalar fusion without relief of lateral symptoms. Eleven patients (group II) underwent a lateral decompression as an alternative to late subtalar fusion. In both groups combined, there were 14 males and 5 females with an average age of 40 years. The average follow-up was 28 months in group I and 17 months in group II. A satisfactory result was obtained in 75% (6 of 8) of the patients in group I and in 82% (9 of 11) of the patients in group II. This compares to a published success rate of approximately 50% in selected series in the literature and the authors' similar success rate of 46% for late subtalar fusion for the same pathology. The results suggest that the lateral decompression procedure offers a technically simpler yet effective alternative to late subtalar fusion for lateral pain following a malunited os calcis fracture with subtalar intra-articular involvement.

The Chevron osteotomy has become popular for the treatment of hallux valgus deformity. Displacement of the osteotomy is a known complication. Many methods of internal fixation have previously been reported to prevent the displacement and each has inherent advantages and disadvantages. An alternative method of fixation, utilizing absorbable polydioxanon pins, is presented in this article. Between April 1989 and April 1990, 71 procedures were performed on 50 patients. At 1-year follow-up, there were no complications or infections. Review of the osteotomy after surgery and at 1 year revealed no fractures or displacements, and no pins required removal. Internal fixation utilizing absorbable polydioxanon pins appears to have significant benefits when compared with metallic fixation.