RATES AND OUTCOMES OF PRIMARY AND REVISION TOTAL HIP REPLACEMENT IN THE UNITED STATES MEDICARE POPULATION
Bibliographic record
Abstract
BACKGROUND: Information on the epidemiology of primary total hip replacement is limited, and we are not aware of any reports on the epidemiology of revision total hip replacement. The objective of this study was to characterize the rates and immediate postoperative outcomes of primary and revision total hip replacement in persons sixty-five years of age and older residing in the United States. METHODS: We used Medicare claims submitted by hospitals, physicians, and outpatient facilities between July 1, 1995, and June 30, 1996, to identify individuals who had undergone elective primary total hip replacement for a reason other than a fracture (61,568 patients) or had had revision total hip replacement (13,483 patients). Annual incidence rates of primary and revision total hip replacement were calculated, and multivariate modeling was used to evaluate the association between patient characteristics and surgical rates. The rates of occurrence of five complications within ninety days postoperatively were also evaluated, and relationships between those outcomes and patient characteristics were assessed with use of multivariate models adjusted for hospital and surgeon volume. RESULTS: The rates of primary total hip replacement were three to six times higher than the rates of revision total hip replacement. Women had higher rates than men, and whites had higher rates than blacks. The rates of primary and revision total hip replacement increased with age until the age of seventy-five to seventy-nine years and then declined. The rates of complications occurring within ninety days after primary total hip replacement were 1.0% for mortality, 0.9% for pulmonary embolus, 0.2% for wound infection, 4.6% for hospital readmission, and 3.1% for hip dislocation. The rates after revision total hip replacement were 2.6%, 0.8%, 0.95%, 10.0%, and 8.4%, respectively. Factors associated with an increased risk of an adverse outcome included increased age, gender (men were at higher risk than women), race (blacks were at higher risk than whites), a medical comorbidity, and a low income. CONCLUSIONS: Analysis of United States Medicare population data showed that the rates of total hip replacement increased with age up to the age of seventy-five to seventy-nine years and that blacks had a significantly lower rate of total hip replacement than whites. The overall rates of adverse outcomes were relatively low, but they were significantly higher after revision than after primary total hip replacement. LEVEL OF EVIDENCE: Prognostic study, Level II-1 (retrospective study). See p. 2 for complete description of levels of evidence.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".