Early migration characteristics of a hydroxyapatite-coated femoral stem: an RSA study.

Measurement of early stem subsidence can be used to predict the likelihood of long-term femoral component loosening and clinical failure. Data that examines the early migration pattern of clinically proven stems will provide clinicians with useful baseline data with which to compare new stem designs. This study was performed to evaluate the early migration pattern of a hydroxyapatite-coated press-fit femoral component that has been in use for over ten years. We enrolled 30 patients who underwent THA for osteoarthritis. The median age was 70 years (range, 55-80 years). Patients were clinically assessed using the Harris hip score. Radiostereometric analysis was used to evaluate stem migration at three to four days, six months, one year and two years. We observed a mean subsidence of 0.73 mm at six months, 0.62 mm at one year and 0.58 mm at two years and a mean retroversion of 1.82° at six months, 1.90° at one year and 1.59° at two years. This data suggests that subsidence is confined to the first six months after which there was no further subsidence. The results from this study can be compared with those from novel cementless stem designs to help predict the long-term outcome one may expect from new cementless stem designs.

Incidence and outcomes of knee and hip joint replacement in veterans and civilians.

BACKGROUND: This article describes the incidence of total knee and hip replacement, and compares post-surgery health status outcomes in veterans and civilians. METHODS: The numbers of male veterans and civilians who had a knee and/or a hip replacement in South Australia (1994-2002) were obtained. Standardized morbidity ratios, and odds ratios for age group by veteran/civilian interactions, were calculated. Presurgery and 1-year post-surgery Medical Outcomes Short Form (36) Health Survey, Knee Society and Harris hip scores were completed. Independent samples t-tests were used to compare presurgery scores. ancova models were used to determine any differences between veterans and civilians post-surgery. RESULTS: For veterans, standardized morbidity ratios were 0.987 and 0.715 for knee and hip replacements, respectively (P < 0.0001). Veterans' odds ratios for knee and hip replacements were significantly lower in the 65- to 74-year age group (P < 0.001), similar in the 75- to 84-year and above 85-year age groups for hip replacement, but significantly higher in the above 85-year age group for knee replacement (P < 0.001). Presurgery, veterans reported significantly lower scores (P < 0.003) for knee function. After knee replacement, veterans reported significantly lower Medical Outcomes Short Form (36) Health Survey scores for bodily pain, physical functioning, role - physical, role--emotional, social functioning and physical component summary (P < 0.033). Significantly lower physical functioning, role--physical and physical component summary scores (P < 0.02) were reported by veterans post-surgery for hip replacement. CONCLUSION: Veterans are delaying joint replacement. Presurgical knee function is worse in veterans. Post-surgery, the veterans are worse off in a number of health status outcomes.

Number, incidence, and projections of distal forearm fractures admitted to hospital in Australia.

BACKGROUND: This study documents the number, incidence, and relative risk (RR) of distal forearm fractures requiring admission to hospital in Australia in 1997 and estimates of the projected numbers for 2021. METHODS: Distal forearm fracture numbers from 1993 to 1998 were obtained. The incidence and RR were calculated by gender and 5-year age groups for 1997. Projected numbers for 2021 were estimated using population projection data. RESULTS: In 1997, fracture numbers were 12357 for male patients and 19319 for female patients. The incidence was 152 per 100000 for male patients and 157 per 100000 for female patients. The highest incidence and RR was in the 10- to 14-year age group for male patients and in the 85 years and over age group for female patients. If fracture incidence remains constant (on the basis of predicted population changes in Australia), by 2021, it is estimated that fracture numbers for people 50 years of age and over will increase by 81%, compared with 11% for people under 50. In the older age group, the number for women will be 4.7 times higher than for men. CONCLUSION: This study quantifies the potential disproportionate increase in distal forearm fractures requiring admission in Australia, particularly for female patients, because of an aging population.