Extra-articular migration of the patellar component following total knee arthroplasty.

Complications related to patellar resurfacing are well recognized. We present an unusual case where the patellar button, after separating from the patella, extruded from the knee joint to lie within the extra-articular soft tissues.

Altered venous function and deep venous thrombosis following proximal femoral fracture.

The effect of surgery for femoral neck fracture on lower limb venous blood flow and its relationship to deep vein thrombosis was investigated in 179 patients. Blood flow was measured using strain gauge plethysmography before surgery, in the 1st week after surgery, and at 6 week review. There was a significant reduction in both venous outflow and venous capacitance, affecting both fractured and non-fractured legs but significantly greater in the fractured leg. Venous function remained significantly impaired in both lower limbs 6 weeks after surgery. There was a significant correlation between the reduction in venous function and the development of deep vein thrombosis.

Analysis of the sit-stand-sit movement cycle in normal subjects.

OBJECTIVE: This study aimed to establish a basis of descriptive data for the sit-stand-sit movement cycle in 50 normal subjects, 25 male and 25 female, aged between 20.1 and 78.3 years (mean age 46.8 years). DESIGN: A descriptive design was employed to establish the characteristics of the activity in normal subjects. BACKGROUND: Research has been carried out into kinetic and kinematic characteristics of the sit-to-stand movement, but few researchers have considered stand-to-sit. Most studies have involved small samples, subjects with pathology, or elderly subjects, so a baseline of data from normal subjects has not yet been established. METHOD: Linear displacement and acceleration of the trunk and angular displacement of the knee were recorded simultaneously within the same temporal framework. The measurement system consisted of a vector stereograph, and triaxial accelerometers located at the level of C(7), and an electrogoniometer located at the lateral aspect of the knee. Subjects rose from and descended to the seated position a total of six times at their own self-selected speed. Numerical data were subjected to descriptive analysis, matched-pairs t tests and Pearson's rho correlations. RESULTS: Mean values for the time to rise was 1.91 s and to descend was 1.97 s. Forward lean velocity was greater during rising than descending (P < 0.001), and recovery velocity was greater during descending than rising (P < 0.001). Temporal contributions of forward lean and vertical displacement and the period of overlap between them were identified, and relationships between acceleration and temporal events and components were established. Differences existed among groups, involving primarily the elderly groups and occurring during the rising phase. CONCLUSIONS: This study has proposed a baseline of descriptive data in normal subjects for the sit-stand-sit movement cycle. RELEVANCE: In practical and clinical applications of information gained from analysis of functional activities, establishment of what is accepted as 'normal' is necessary before abnormalities can be identified and analysed, and intervention implemented and evaluated. This study provides that basis.