{'fraction_non_alphanumeric': 0.032116788321167884, 'fraction_numerical': 0.021897810218978103, 'mean_word_length': 4.942196531791907, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 1, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
What's new in total hip arthroplasty.

It has been nearly a decade since the introduction of this Specialty Update section in The Journal. We have covered many topics that were considered to be contemporary and controversial. In the current update, we have elected to include reviews on (1) the outcomes of primary total hip arthroplasty, (2) the outcomes of revision hip arthroplasty, (3) hip resurfacing arthroplasty, (4) complications, and (5) practice management. The major new information in the past year is in epidemiology and hip resurfacing arthroplasty.

### Epidemiology

Total joint arthroplasty volume is projected to continue to increase. Kurtz et al. used the Nationwide Inpatient Sample (NIS) to make projections and to analyze population-based outcomes of total joint arthroplasty. They projected that >50% of all joint arthroplasties will be performed in patients less than sixty-five years of age by 2011. Moreover, younger patients will account for 52% of all total hip arthroplasties and 55% to 62% of all primary and revision total knee arthroplasties by 2030. This projection may have implications for the private sector with regard to insurance coverage and reimbursement for joint arthroplasty procedures in the future.

### Clinical Outcome

#### Femoral Stem

Hip resurfacing arthroplasty has become increasingly popular worldwide. One of the proposed advantages of resurfacing is that the outcome and durability are superior to those of conventional total hip arthroplasty, especially in younger patients. Springer et al. conducted a systematic review of three databases of published results of total hip arthroplasties performed with use of contemporary designs and cementless fixation in young patients. The meta-analysis included 5907 patients (6408 hips) less than fifty-five years of age. These patients were compared with 3002 patients with 3269 hip resurfacing arthroplasties. The pooled failure rate for the femoral stem was 1.3% at a mean of 8.4 years, compared with a failure rate of 2.6% at a mean of 3.9 years for …