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Heterotopic ossification in total hip arthroplasty: the significance for clinical outcome
1Department of Orthopedic Surgery, University of Berne, Inselspital, Switzerland.
Insights
Heterotopic ossification (HO) significantly impacts total hip replacement outcomes. This study found increasing HO degrees correlated with reduced joint function and patient satisfaction, highlighting HO as a critical factor in clinical results.
Area of Science:
- Orthopedic Surgery
- Biomedical Engineering
- Clinical Research
Background:
- Heterotopic ossification (HO) is a potential complication following total hip replacement (THR).
- Understanding the clinical impact of HO is crucial for patient outcomes.
- This study excluded patients receiving HO prophylaxis to isolate the effects of spontaneous HO.
Purpose of the Study:
- To investigate the correlation between heterotopic ossification and clinical outcomes after primary total hip replacement.
- To quantify the impact of varying degrees of HO on functional parameters and patient satisfaction.
Main Methods:
- Prospective, multicenter study of 706 patients undergoing 835 primary total hip replacements.
- Patients were not given prophylaxis against HO.
- Clinical and radiological follow-up averaged 3.1 years, assessing HO using Brooker grading.
Main Results:
- Heterotopic ossification (HO) was observed in 47% of total hip replacements.
- Mild HO (Brooker I) in 29.1%, moderate (Brooker II) in 12.7%, and severe (Brooker III/IV) in 5.2%.
- Increasing HO severity significantly correlated with decreased flexion range, reduced spreading distance, and diminished patient satisfaction.
Conclusions:
- Heterotopic ossification negatively impacts clinical outcomes and patient satisfaction after total hip replacement.
- The degree of HO directly correlates with functional limitations, particularly range of motion.
- Managing or preventing HO is essential for optimizing total hip replacement success.
Abstract:
This study evaluates 706 patients with 835 primary total hip replacements documented in a prospective fashion in a multicenter study with respect to correlation between heterotopic ossification (HO) and clinical outcome. Only patients without prophylaxis against HO entered the study. The mean clinical and radiological follow-up was 3.1 years (+/- 0.7). Heterotopic ossification was noted in 47% of all total hips replaced. It was graded as mild (Brooker I) in 29.1%, moderate (Brooker II) in 12.7%, and severe (Brooker III and IV) in 5.2%. All clinical parameters investigated were significantly affected with the increasing amount of heterotopic ossification. The strongest correlation was found in flexion range and spreading distance. Both factors were significantly decreased with higher degrees of ossification. The other clinical parameters investigated, walking capacity, limp, and use of analgesics, were altered to a lesser extent and only with higher degrees of heterotopic bone formation. Finally, patient satisfaction was significantly influenced by the degree of heterotopic ossification and dropped from almost 90% good or excellent patient satisfaction in the non-ossification group to less than 30% in the group with severe ossification.
