Personality, function and satisfaction in patients undergoing total hip or knee replacement.

BACKGROUND: The aim of this study was to investigate the relationships between personality and joint-specific function, general physical and general mental health in patients undergoing total hip (THA) and knee arthroplasty (TKA). METHODS: One hundred and eighty-four patients undergoing THA and 205 undergoing TKA were assessed using the Eysneck Personality Questionnaire, brief version (EPQ-BV). General physical and mental health was measured using the Short-Form 12 (SF-12) questionnaire and the EuroQol (EQ-5D). Joint-specific function was measured using the Oxford hip or knee score. RESULTS: The "unstable introvert" personality type was associated with poorer pre-operative function and health in patients with hip arthrosis. In patients with knee arthrosis, there was poorer general health in those with "stable extrovert" and "unstable introvert" types. Personality was not an independent predictor of outcome following TKA or THA. The main predictor was pre-operative function and health. Comorbidity was an important covariate of both pre-operative and postoperative function. CONCLUSIONS: Personality may play a role in the interaction of these disease processes with function and health perception. It may also affect the response and interpretation of psychometric and patient-reported outcome measures. It may be important to characterise and identify these traits in potential arthroplasty patients as it may help deliver targeted education and management to improve outcomes in certain groups.

A micro-architectural evaluation of osteoporotic human femoral heads to guide implant placement in proximal femoral fractures.

BACKGROUND AND PURPOSE: The micro-architecture of bone has been increasingly recognized as an important determinant of bone strength. Successful operative stabilization of fractures depends on bone strength. We evaluated the osseous micro-architecture and strength of the osteoporotic human femoral head. MATERIAL AND METHODS: 6 femoral heads, obtained during arthroplasty surgery for femoral neck fracture, underwent micro-computed tomography (microCT) scanning at 30 µm, and bone volume ratio (BV/TV), trabecular thickness, structural model index, connection density, and degree of anisotropy for volumes of interest throughout the head were derived. A further 15 femoral heads underwent mechanical testing of compressive failure stress of cubes of trabecular bone from different regions of the head. RESULTS: The greatest density and trabecular thickness was found in the central core that extended from the medial calcar to the physeal scar. This region also correlated with the greatest degree of anisotropy and proportion of plate-like trabeculae. In the epiphyseal region, the trabeculae were organized radially from the physeal scar. The weakest area was found at the apex and peripheral areas of the head. The strongest region was at the center of the head. INTERPRETATION: The center of the femoral head contained the strongest trabecular bone, with the thickest, most dense trabeculae. The apical region was weaker. From an anatomical and mechanical point of view, implants that achieve fixation in or below this central core may achieve the most stable fixation during fracture healing.

What is the relevance of the tip-apex distance as a predictor of lag screw cut-out?

Using a simple mathematical formulation, the relationship between the position of the lag screw tip (relevant to both intramedullary and extramedullary devices) and the concept of tip-apex distance (TAD) was derived. TAD is widely used in operating theaters as a surgical guideline in relation to the fixation of trochanteric fractures, and in clinical studies as a predictor of lag screw cut-out. In order to visualize better this concept, the locus of points having the same TAD was plotted and the dependence of TAD on the location of the lag screw tip was also reported. It was shown that TAD should be adjusted for the size of the femoral head (a variable which varies a lot according to the sex of the patient) while no correlation was found between TAD and bone morphometry indices obtained from micro-CT data (BV/TV and Tb.Th). Therefore, these results seem to suggest that TAD lacks mechanical justification and that predictors which are based on mechanical properties, such as bone density, should be investigated further.

Chronic osteomyelitis of the pelvis.

The aim of this study was to examine the aetiology and response to treatment of a series of patients with pelvic osteomyelitis. Criteria for selection were multiple positive intra-operative cultures and/or a positive radiological diagnosis. Twenty patients met these criteria (age range: 21-78 years, mean = 46). Data was recorded on host status using the Cierny-Mader classification, neurological status, causative organisms; sensitivities were recorded and the treatment and its outcome. Pelvic osteomyelitis was frequently caused by unusual organisms; a high incidence (45%) of neurologically compromised patients was noted. There were important differences in infective organisms, treatment and outcome in the paraplegic and non-paraplegic population. A high mortality and a high incidence of squamous cell carcinoma was observed. Pelvic osteomyelitis should be managed differently to long bone osteomyelitis as far as the antibiotic therapy is concerned, with a greater need for broad spectrum antibiotics in pelvic osteomyelitis. The response to surgical resection was similar to long bone osteomyelitis with a high chance of success with marginal resection in type A hosts and with wide resection in type B hosts.