Quantitative analysis of widespread osteolysis in the proximal end of cemented and cementless prostheses in total hip arthroplasty

Yong ZHANG; Tongtao YANG; Yong ZHOU; Baoan MA

ABSTRACT

BACKGROUND:

At present, there are only morphological observation about the femoral osteolysis in domestic literatures and reports of quantita tive study are also few.

OBJECTIVE:

To quantitatively analyze the changing status of osteolysis in proximal femur after total joint replacements (TJR) through the changing rules of bone density in proximal end of femur.

DESIGN:

Observation on patients before and after self-comparison.

SETTING:

Department of Orthopedics, Tangdu Hospital of Fourth Military Medical University of Chinese PLA.

PARTICIPANTS:

Twenty-eight hips in 26 patients received total hip replacements in the Department of Orthopedics, Tangdu Hospital of Fourth Military University from March 1994 to March 2004, including 16 hips in 14 male patients and 12 hips in 12 female patients, were selected. Types of prostheses 17 hips in 16 patients with ameliorated Moore cemented prostheses were taken as cemented prosthesis group with a mean age of 57 years; 11 hips in 10 patients with microbores on the surface of implant were taken as cementless prosthesis group with a mean age of 55 years.Patients were diagnosed as traumatic arthritis before operation with the mean Harris score of 49 (20-77) points on hip. Age, gender and diagnosis after operation in patients of two groups were matched.

METHODS:

The gray degrees of X-ray in patients of two groups were measured with computer image analyzing, relative values were obtained,I.e. The average gray degrees of 1.0-2.0 cm2 area in femoral trochanter and iliac bone were measured with the same X-ray; Differences between them represented the relative value of bone density in greater trochanter of femur. Changing rules of bone density were quantitatively analyzed.MAIN OUTCOME

MEASURES:

Relative values of bone density in greater trochanter of femur of patients in two groups one week before and after operation, during the follow-up time were measured respectively.

RESULTS:

A total of 26 patients (28 hips) with the follow-up time of 9-126months were all involved in the analysis of results. Relative values of bone density were increased to different degree one week after operation. And rate of osteolysis was 100% with a mean value of 57.4 (9-118) in greater trochanter of femur from 17 hips of 16 patients in the cemented group during the follow-up time; Relative value of bone density in greater trochanter of femur in 10 hips of 11 patients in the cementless group during the follow-up time were increased to different degree one week after operation.Rate of osteolysis changing was 100% with a mean value of 72.8 (14-130).Differences between two groups were not significant (P ＞ 0.05). Changes of osteolysis firstly appeared in the 9th month of post-operation and were obvious 2-4 years after operation and lessened in the 6th year.

CONCLUSION:

There are osteolysis in cemented and cementless prostheses after total hip replacement and no significant differences between two kinds of prostheses.