Understanding the foot's functional anatomy in physiological and pathological conditions: the calcaneopedal unit concept.

BACKGROUND: A thorough review of the available orthopaedic literature shows significant controversies, inconsistencies and sparse data regarding the terminology used to describe foot deformities. This lack of consensus on terminology creates confusion in professional discussions of foot anatomy, pathoanatomy and treatment of deformities. The controversies apply to joint movements as well as static relationships between the bones. DESCRIPTION: The calcaneopedal unit (CPU) is a specific anatomical and physiological entity, represented by the entire foot excepted the talus. The calcaneus, midfoot and forefoot are solidly bound by three strong ligaments that create a unit that articulates with the talus. The movement of the CPU is complex, as it rotates under the talus, around the axis of Henke that coincides with the talo-calcaneal ligament of Farabeuf.This calcaneopedal unit is deformable. It is compared with a twisted plate, able to adapt to many physiological situations in standing position, in order to acheive a plantigrade position.Moreover, the calcaneopedal unit and the talo-tibiofibular complex are interdependent; rotation of the latter produces morphologic modifications inside the former and vice versa. PURPOSE: This paper is a review article of this concept and of its physiopathological applications.

Validity and reliability of different techniques of neck-shaft angle measurement.

AIM: To determine a valid and reliable neck-shaft angle (NSA) measurement method while rotating the pelvises in increments of 5° in order to simulate patient malpositioning. MATERIALS AND METHODS: CT images of 17 patients were used to produce digitally reconstructed radiographs in frontal and lateral views and three-dimensional (3D)-reconstructions of the femurs, considered to be the reference standard. Malpositioning was simulated by axially rotating the frontal radiographs from 0° to 20°. Three operators measured in two-dimensions the NSA using four different methods, three times each, at each axial rotation (AR) position. Method 1 (femoral neck axis drawn by joining the centre of the femoral head (CFH) to the median of the femoral neck base; femoral diaphysis axis drawn by joining the median of two lines passing through the medial and lateral edges of the femoral axis below the lesser trochanter) and method 2 (femoral axis taken as the median of a triangle passing through base of femoral neck and medial and lateral head-neck junction; femoral diaphysis as previous) were described for the first time; method 3 was based on a previous study; method 4 was a free-hand technique. Reliability, validity, and global uncertainty were assessed. RESULTS: Method 1 showed the best reliability and validity. The global uncertainty also showed minimal values for method 1, ranging from 7.4° to 14.3° across AR positions. CONCLUSION: Method 1, based on locating the CFH, was the most reliable and valid method and should be considered as a standardised two-dimensional NSA measurement method for clinical application.

Normative spino-pelvic sagittal alignment of Lebanese asymptomatic adults: Comparisons with different ethnicities.

BACKGROUND: Normative values of sagittal alignment are used as references for the diagnosis and treatment of spinal pathologies. There are currently no reference values for the normative sagittal alignment of Lebanese subjects. The objective is to describe normative values of full body sagittal alignment parameters in asymptomatic Lebanese adults and to compare the sagittal alignment of this population to that of populations of various origins. METHODS: Included subjects were aged 18 to 28 years old. Each subject underwent a full body biplanar X-ray exam with measurement of spine, pelvis and lower limb parameters of sagittal alignment. The sagittal alignment of the Lebanese population was compared to that of other ethnicities, previously reported in the literature, using one-way ANOVA. RESULTS: Ninety-two asymptomatic Lebanese young adult volunteers (48 males, 44 females, age=21.5±2.2 years) were enrolled in this study. The mean curvature in the cervical spine was kyphotic (-4.3°) in women, while it was lordotic in men (5.4°). Men were found to be significantly more kyphotic than women (-58.3° vs. -53.0°; p<0.01) but both sexes were found to have similar lordosis (61.6°) and pelvic incidence (52.0°). Lebanese subjects had intermediate pelvic incidence compared to other ethnicities but showed significantly higher thoracic kyphosis (p<0.01) and lumbar lordosis (p<0.01) compared to all other ethnicities. CONCLUSIONS: This study established reference normative values for young adult Lebanese subjects. Most women were found to have kyphotic cervical spines. The sagittal alignment of Lebanese subjects differed significantly compared to that of other ethnicities. LEVEL OF EVIDENCE: Level IV - cross sectional study.