Trabecular and subchondral bone development of the talus and distal tibia from foal to adult in the warmblood horse.

Horses are precocial animals and able to stand and walk within hours after birth. To cope with associated loading, intrauterine bone development has shown to be anticipative. This study provides further insight into the post-natal development of structurally important features of trabecular and subchondral bone of the talus and sagittal ridge of the tibia of warm-blooded horses. In all areas studied, the average bone volume fraction showed a gradual increase over time, which was the result of a significant increase in trabecular thickness, without significant changes in the degree of anisotropy. Similar to the mineralised part of the bone, collagen content, measured as average retardation using polarised light microscopy, increased significantly, but the degree of anisotropy of the collagen type I network did not. At birth, the subchondral bone layer had a more trabecular aspect, gradually changing to an even surface with only a few vascular canals at an age of 2 months. Presented results indicate the necessity for a stronger structure, but not for a different structural design after birth, providing further evidence for anticipatory bone development in the horse. More knowledge about the strategies used to cope with mechanical loading after birth might be helpful in understanding the developmental bone and joint diseases.

Growth Disturbance of the Distal Tibia in Patients With Idiopathic Clubfeet: Ankle Valgus and Anteflexion of the Distal Tibia.

BACKGROUND: The aim of this study was to evaluate the incidence of deformities of the distal tibia in patients with idiopathic clubfeet who had undergone surgical intervention with a circumferential release through a Cincinnati incision in early infancy. METHODS: A retrospective follow-up evaluation of children with idiopathic clubfoot was conducted. We reviewed children who had undergone surgical treatment by a circumferential release in our department after unsuccessful casting, and who were at least 10 years of age. Main focus was the measurement of anteroposterior and lateral view radiographs for distal tibia deformities. Of 65 patients (93 feet) who had surgery for idiopathic clubfoot from 1998 to 2002, radiographic data of 35 patients (52 feet) were analyzed. RESULTS: An anteflexion deformity was present in 25 of 52 feet (48.1%) and a valgus deformity in 29 of 52 feet (55.8%). A flat-top talus was evident to some degree in all cases. An abnormal lateral talocalcaneal angle was evident in 42.3%. CONCLUSIONS: These results show the importance of conducting follow-up evaluations on patients with idiopathic clubfoot for secondary deformities of the distal tibia. This is the first study, to our knowledge, highlighting the high incidence of distal tibial deformities after surgery for idiopathic clubfoot. It is unclear at this time whether this is also true for clubfeet after conservative treatment. However, patients with clubfeet should have radiographs of the ankle joint between the age of 10 and 12 years to be able to treat possible deformities through guided growth. LEVEL OF EVIDENCE: Level III.

Talar maturity determined by epiphyseal closure of the calcaneus.

The talus is used in many kinds of studies on primates including fossil species, and most of the individuals studied are adults. One of the most important indicators of adult individuals is epiphyseal closure; however, because the talus has no epiphysis, it is difficult to determine the maturity of the talus. The calcaneus has one epiphysis, and it has been used along with the talus in some analyses. The objective of this study was to quantify the maturation trajectory of the talus using epiphyseal closure of the calcaneus as a benchmark. We used 71 skeletons of free-ranging Macaca fuscata fuscata males of known day-age. We did not identify any size increase with age in talar dimensions among specimens with complete calcaneal epiphyseal closure. Thus, in male M. fuscatafuscata, the maturation trajectory of the talus can be quantified using epiphyseal closure of the calcaneus as a benchmark.

The ossific nuclei and the cartilage anlage of the talus and calcaneum.

We studied the ossific nuclei on radiographs of the feet of three stillborn infants, two with club feet, relating the size, position and alignment of each nucleus to the cartilaginous talus or calcaneum in which it lay. Anteroposterior projections of the nucleus of the talus show deformity of that bone as well as subtalar malalignment. Lateral projections of the calcaneal nucleus may underestimate the degree of hindfoot equinus.

Growth and development of the tibia, fibula, and ankle joint.

Deformities of the leg and ankle may result from growth abnormalities of the tibia and fibula. Measurements of the distance between the proximal tibial and fibular physes, the distal tibial and fibular physes, and the angle between the long axis of the tibia and the distal tibial physis and talar dome were made to determine the changes that occur during normal skeletal development. These measurements demonstrate that early detection of growth discrepancy is possible.