1. Previous papers on the subject of the os trigonum are reviewed. 2. Evidence is produced to show that the posterior part of the talus normally develops from separate centres. 3. An explanation is given for the presence in adults of separate ossicles (the so-called os trigonum) in one or both ankles and for the variety of shapes adopted by them. 4. Contrary to opinions expressed by previous writers, these ossicles may give rise to symptoms

Eleven patients were reviewed an average of 23 years after they had been treated by excision of a symptomatic calcaneonavicular bar in 16 of their feet. Of these feet 69% (11 feet) had a good or excellent result. Of the five failures, three feet had good results after subsequent triple arthrodesis, but two treated by repeated excision of the bar were still unsatisfactory. Beaking of the talus seen before operation correlated with poor results

The results of triple arthrodesis performed in 80 feet and followed for an average of 13 years are reviewed. Although the majority of patients were very pleased, the results of objective assessment were less favourable. There was a high incidence of degenerative joint changes in the ankle and midfoot and also of pseudarthrosis, avascular necrosis of the talus and residual deformity. Pre-operative rigid equinovarus deformity produced the majority of the poor results. It is suggested that bony resection alone might not be the best means of correcting severe equinus

1. An anatomical study of congenital club foot in various stages of foetal development is presented, and the literature is reviewed. 2. The most striking finding was deformity of the talus and in particular a change in its angle of declination. 3. That deformity was present in feet whose deformity could not be corrected by gentle manipulation; it was absent in feet whose deformity could be so corrected. 4. Abnormality of the tendon and insertion of the tibialis posterior muscle was found in most cases. 5. Speculations are advanced concerning the nature and cause of the talar deformity

1. Twenty-three patients were treated by cross screwing for diastasis of the tibia and fibula in fractures at the ankle. 2. It is suggested that limitation of ankle dorsiflexion after this treatment was caused by the presence of a mechanical block to dorsiflexion by spur formation at the margins of tibia and talus. 3. An ordinary bone screw controlled the diastasis satisfactorily in twenty patients. 4. The screw did not interfere with movement at the inferior tibio-fibular joint because bone resorption about that part of the screw in the fibula allowed a small range of movement. 5. Discomfort from the screw was relieved by its removal

Talectomy was performed on 10 patients (15 feet) for club foot deformity in arthrogryposis multiplex congenita. These were reviewed after an average follow-up of eight years. At follow-up nine feet were plantigrade, and six had less than 15 degrees residual equinus at the ankle. All the feet were asymptomatic but had mild residual adduction of the forefoot and marked stiffness of the hindfoot. Seven feet developed spontaneous bony ankylosis in the tibiotarsal joint. The common technical errors were incomplete removal of the talus and incorrect positioning of the calcaneus in the ankle mortise

Nine patients have been reviewed at an average period of 22 years after a Watson-Jones tenodesis performed for chronic instability of the ankle. Only three patients had complete relief of symptoms. Two favourable early results deteriorated 7 and 10 years after operation. Radiographic examination revealed full correction of both anterior and lateral instability of the talus in only two cases. Talar tilt was controlled more successfully than increased anterior drawer movement. Long-standing instability was associated with the formation of marginal exostoses, the severity of which appeared proportional to the degree of instability

The range of rotation of the talus in the horizontal plane was studied in the cadaveric ankle under conditions which simulated normal load-bearing. In the unloaded state there was 25 degrees of rotation, approximately half of which resulted from movement of the inferior tibiofibular joint. Rotation was load-dependent in both the intact ankle and in the ankle rendered unstable by division of the ligaments. Experimental division of the ligaments increased the range of rotation. The malleoli were contact areas during flexion and extension but excision of their articular surfaces caused only a moderate increase in rotation. The factors which limit talar rotation in intact and injured ankles are discussed

Fourteen cases of pseudarthrosis of the tibia in childhood presented at a hospital in Burma over a period of eight years. The ages of the patients ranged from one month to seventeen years. Nine were treated by a pointed graft driven into the medullary cavity of the distal tibia, and usually across the ankle joint into the body of the talus, before fixation to the proximal tibia. In six of the nine union was secured, but one case required a second grafting. Transarticular segments of graft showed a marked tendency to undergo absorption. No significant deformity was observed to follow central penetration of the growth plate and epiphysis of the lower tibia

1. Thirteen cases of fracture of the lateral process of the talus seen over a period of thirteen months are reported. 2. The mechanism of the injury would appear to be inversion strain of the foot with dorsiflexion of the ankle. 3. The diagnosis would no doubt be made more often if the possibility of this fracture were kept in mind, and if radiographs of good quality were taken with the ankle at 0 degree and the leg rotated inwards 10 to 20 degrees. 4. With regard to treatment, early operation appears to give good results, a single large fragment being reduced accurately and small or comminuted fragments being removed

1. The record is presented of an attempt to treat osteochondritis dissecans on idealistic lines. 2. The operative technique to be adopted in the various circumstances likely to be encountered in the knee joint is described. Two cases affecting the talus are recorded. 3. The radiological appearance has become virtually normal in twenty-seven cases (the remaining four are recent); healing has been observed directly in seven cases in which a second operation to remove the means of internal fixation was necessary; and the patients' complaints have been eliminated, but the long term results of treatment are unknown. 4. Suggestions are made for possible developments in the technique of operation

1) Supination and pronation are the only material tarsal movements; other terms describe their hypothetical components only. 2) The subtalar and talo-navicular joints form a single joint functionally, which may be called the peritalar joint. 3) Peritalar movement comprises a wide range of supination and pronation of the foot about an axis which passes from the tuberosity of the calcaneum upwards, forwards and slightly medially to the neck of the talus. 4) Midtarsal movement comprises a narrow range of supination and pronation of the foot about an axis similar to that of peritalar movement. 5) Tile peritalar and midtarsal joints are thus oblique hinge joints

1. Nineteen patients with spina bifida, myelomeningocele or lipoma of the cauda equina have been reviewed. Convex pes valgus was found in twenty-five feet. All patients had a neuromuscular imbalance between the evertors and invertors of the foot. 2. Results of release procedures only and of those which combine release procedures with tendon transfers are compared; they show that there is no consistently satisfactory operation for correction of the deformity when it exists with neuromuscular imbalance. 3. An operation in which release procedures are combined with the transfer of the peroneus brevis to the tibialis posterior and of the tibialis anterior to the neck of the talus is described. It has given satisfactory results in two out of three patients with paralytic convex pes valgus

Ligamentous instability of the ankle joint can be confirmed by radiographs taken in two planes. The place of the anteroposterior varus stress view is established, but the lateral view which shows anterior subluxation of the talus is frequently omitted. The anatomical significance of the two stress views has been determined by dividing different components of the lateral ligament of 20 cadaveric ankles and noting the subluxation that resulted from these procedures. A clinical assessment was then made of 54 ankles (46 patients) with radiological evidence of instability when subjected to varus and anterior stress. Anterior subluxation was found to be considerably more common than varus tilt, and it is therefore suggested that the lateral stress view should be an essential part of the investigation of the unstable ankle

1. Lateral radiographs of fifty-seven club feet and seventeen normal feet were taken in forced flexion and forced extension. On these, the arcs traversed by the talus, the sole and the calcaneus were measured, as was the talo-calcaneal angle. 2. It was found that the ankle in club feet usually contributed more than half of the total sagittal movement of the foot. 3. Occasional cases were encountered in which the ankle was so damaged that it contributed only half or less than half of this movement. In such cases wedge excision of the ankle joint is theoretically justified in preference to wedge tarsectomy. 4. The talo-calcaneal angle is much reduced in club foot, and this element of deformity is extremely resistant to manipulative treatment. The reasons for this and a possible method of treatment are discussed

We investigated a new method of stress radiography of the subtalar joints using forced maximum dorsiflexion of the ankle in a supinated position. We measured transposition of the lateral process of the talus at the posterior subtalar joint in lateral views of normal amputated ankles, normal control subjects and patients with recurrent ankle sprains. The mean displacement in the control groups (n = 36) was 29.9%, significantly different from the 43.0% in patients with recurrent ankle sprains (n = 24). In the amputated specimens with intact ligaments movement was similar to that in normal subjects. Section of the calcaneofibular and the interosseous ligaments allowed much the same movement as in patients with recurrent ankle sprains. The new method is simple and useful for detecting subtalar instability

Of 23 children (35 feet) with cerebral palsy who had undergone a Grice extra-articular subtalar arthrodesis for a valgus hindfoot between 1976 and 1981, we reviewed 17 (26 feet), at a mean of 20 years (17 years 3 months to 22 years 4 months) after operation. Seven were quadriplegic, eight spastic diplegic, and two hemiplegic. They were all able to walk at the time of operation. Thirteen patients (20 feet) were pleased with the Grice procedure, 13 had no pain and 15 (23 feet) were still able to walk. The clinical results were satisfactory for most feet. Radiography showed that the results had been maintained over time but 14 feet developed a mean ankle valgus of 11° (6 to 18) with a compensatory hindfoot varus in 12 feet. No deformity of the talus or arthritis of adjacent joints was noted. The Grice procedure gives good long-term results in children with cerebral palsy

Aims

There is little information about how to manage patients with a recurvatum deformity of the distal tibia and osteoarthritis (OA) of the ankle. The aim of this study was to evaluate the functional and radiological outcome of addressing this deformity using a flexion osteotomy and to assess the progression of OA after this procedure.

The development of lateral tibial torsion in the paralysed lower limb is well documented, but its pathogenesis is poorly understood. This paper attempts to provide an explanation for its development when it is associated with a varus or equinovarus deformity of the hindfoot. Correction of the lateral tibial torsion by supramalleolar derotation tibial osteotomy and reorientation of the ankle mortise appear to unlock the talus from the laterally rotated position, correcting a mobile hindfoot varus deformity and altering soft-tissue tensions about the ankle so that the correction achieved is maintained. In the presence of a fixed hindfoot deformity, supramalleolar derotation tibial osteotomy is useful as a first-stage procedure before corrective osteotomies of the foot. The operation described is technically simple and carries a low morbidity. Twenty supramalleolar derotation tibial osteotomies in 18 patients have been performed with satisfactory results and few complications

A 14-year-old girl with a congenitally deformed and shortened right leg and foot is described. The patient could not bear weight on the deformed limb and had to hop on the left leg. The deformed foot faced backwards and had nine toes. The right leg was shorter than the left by 26 centimetres. Radiologically, the lower end of the right femur was ill-developed and there was no knee joint. There were two fibulae and the tibia and the patella were absent. A through-knee disarticulation was done and a prosthesis fitted later. The amputated leg and foot were dissected. Many of the muscles in the leg and foot were duplicated. There were two calcanei, one talus, one navicular, two cuboids and four cuneiforms. Ther were nine metatarsals, and all the toes had three phalanges except for one which had two