Functional outcomes of total hip arthroplasty in patients aged 30 years or less: a systematic review and meta-analysis.
- R.P. Walker, M. Gee, F. Wong, Z. Shah, M. George, M.J.K. Bankes, A. Ajuied – Department of Orthopaedics, Guy’s and St Thomas’ NHS Foundation Trust and Department of Orthopaedics and Trauma, King’s College Hospital, London, UK
- Hip Int 2016; 26 (5): 424-431
- Level of Evidence:
- Review and meta-analysis of level IV studies.
Walker et al performed a systematic review of outcomes in total hip arthroplasty (THA) in patients < 30 years old. They identified 14 articles from peer-reviewed journals published between 1981 and 2013. Primary outcome measure was the Harris Hip Score (HHS); secondary measures were implant survivorship, effect of fixation (cemented/uncemented stem) and bearing surface (hard-soft/CoC).
In total 743 THAs were included in the analysis with a mean follow up of 8.4 years. Mean patient age was 22.7 years (range 13-30y). Hard-on-soft (metal or ceramic femoral heads) bearings were used in 461 cases and ceramic-onceramic (CoC) bearings in 282 cases. In 457 cases uncemented THA was used whith a mean follow up of 9.9 years. All studies showed similar significant improvement in HHS with a mean difference of 43 points for hard-on-soft bearings and 45.8 points for CoC bearings, statistically not significant. Overall 155 complications were reported, including revisions (5%) and radiographic loosening (5.4%). Further complications were heterotopic ossification (4.3%), dislocation (1.9%), substantial PE wear (2.1%), infection (0.8%), periprosthetic fracture (0.5%), sciatic nerve injury (0.5%), squeaking (1%), ceramic fracture (0.5%), vascular injury (0.2%), and pulmonary embolism (0.2%).
When the bearings of all fixation cohorts were analysed separately, CoC bearings had a revision rate of 1.1% at 11.5 years compared to 7.9% for hard-on-soft bearings at 7.3 years. When only uncemented THAs were assessed the overall revision rate was 1.3% at 9.9 years with a radiographic loosening of 0.2%. For cementless THA the revision rate with CoC bearings was only 0.78% at 12.2 years. In the hard-on-soft group the revision rate was 1.2% at 7.2 years and radiographic loosening was 12.2%.
The authors summarize that the combined revision rate of 5% in this very young patient group is comparable with the results in older patient groups. However, only a large randomized controlled trial comparing cemented/uncemented mode of fixation with CoC vs. hard-on-soft bearings will be able to determine any significant difference.
- Level of evidence low for all included studies (Level IV).
- No differentiation between ceramic- and metal-on-Polyethylene bearings.
- Type of PE not assessed, some early studies included historical gamma-air.
- No information on head size and its influence.
- Revision rate in these very young patients was 5% at 8.4 years, comparable with results of older age groups.
- The results appear to suggest that CoC bearings outperform hard-on-soft couples in terms of improvement in the HHS, revision rate and loosening. However, the differences in bearing surfaces are confounded by differences in fixation and historical (obsolete) polyethylene in the hard-on-soft group. Thus, no conclusions about modern bearing materials can be drawn from Walker’s study.
This literature analysis shows an excellent performance of uncemented THA with CoC bearings in very young patients.