[Is osteolysis associated with a stable total hip replacement asymptomatic?]

It has been reported that periprosthetic osteolysis in a stable cementless total hip prosthesis is often free from symptoms. The aim of this study is to check this assumption and provide details on the clinical presentation of this troublesome and worrying complication of hip arthroplasty.

Between March 1999 and June 2002, 76 hips in 72 patients underwent revision arthroplasty for periprosthetic osteolysis associated with stable ABG I prostheses. This patient group included 53 females and 19 males. The average age at the time of revision was 49 years (range, 32 to 63). The average time between the primary and revision surgery was 54.6 months (range, 23 to 85). The average cup size was 49.7 mm (range, 44 to 60), the modular 28-mm CoCr head was used in 69 hips, 28-mm ceramic head in six hips, and 22-mm CoCr head in one patient.

The following characteristics were recorded: gender, age, type of patient, height, weight, symptoms, diagnosis, ERS, CRP, Harris hip score, cup size, abduction angle and extent of bony defects. The data of symptomatic and asymptomatic patients were compared by parametric or non-parametric tests.

Before revision, 61 hips (80%) were symptomatic. The patients complained of pain or signs of instability or both, and these complaints were taken as indications for revision surgery. The remaining 15 hips (20%) were asymptomatic. The average period from the primary surgery to the appearance of the first symptoms was 43 months (range, 5 to 80). The average Harris hip score before revision was 68 points (range, 37 to 90) and 82 points (range, 10 to 98) in the symptomatic and asymptomatic patients, respectively (p = 0.002). There were no other significant differences between these patients.

The results of our study are in agreement with the findings of Hozack et al., but not with those of Maloney et al. and others who have reported that the progression of osteolysis developing in association with hip arthroplasty can be without symptoms.

Osteolysis developing around a stable cementless hip prosthesis is generally symptomatic, with pain being the most frequent symptom. Even without a periprosthetic fracture, osteolysis may seriously impair the function of a joint and comfort of the patient. Since symptomatic patients are likely to see their attending physicians, it is emphasized that attention should also be paid to asymptomatic patients who have prostheses with unsuitable designs or pairings.