Sunday, January 15, 2012

Results post revision surgery

A few nites ago, I posted something in responce to a readers request:  how are the post revision patients doing.  I found two more journal articles on this topic.  Hope this provides some insight.

J Bone Joint Surg Br. 2007 Nov;89(11):1446-51.

Predictors of quality of life outcomes after revision total hip replacement.

Source

University of British Columbia, Vancouver, Canada. bring7@aol.com

Abstract

A prospective cohort of 222 patients who underwent revision hip replacement between April 2001 and March 2004 was evaluated to determine predictors of function, pain and activity level between one and two years post-operatively, and to define quality of life outcomes using validated patient reported outcome tools. Predictive models were developed and proportional odds regression analyses were performed to identify factors that predict quality of life outcomes at one and two years post-operatively. The dependent outcome variables were the Western Ontario and McMaster Osteoarthritis Index (WOMAC) function and pain scores, and University of California Los Angeles activity scores. The independent variables included patient demographics, operative factors, and objective quality of life parameters, including pre-operative WOMAC, and the Short Form-12 mental component score. There was a significant improvement (t-test, p < 0.001) in all patient quality of life scores. In the predictive model, factors predictive of improved function (original regression analyses, p < 0.05) included a higher pre-operative WOMAC function score (p < 0.001), age between 60 and 70 years (p < 0.037), male gender (p = 0.017), lower Charnley class (p < 0.001) and aseptic loosening being the indication for revision (p < 0.003). Using the WOMAC pain score as an outcome variable, factors predictive of improvement included the pre-operative WOMAC function score (p = 0.001), age between 60 and 70 years (p = 0.004), male gender (p = 0.005), lower Charnley class (p = 0.001) and no previous revision procedure (p = 0.023). The pre-operative WOMAC function score (p = 0.001), the indication for the operation (p = 0.007), and the operating surgeon (p = 0.008) were significant predictors of the activity assessment at follow-up. Predictors of quality of life outcomes after revision hip replacement were established. Although some patient-specific and surgery-specific variables were important, age, gender, Charnley class and pre-operative WOMAC function score had the most robust associations with outcome. 

WOMAC

The Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index is a disease-specific, self-administered, health status measure. It probes clinically-important symptoms in the areas of pain, stiffness and physical function in patients with osteoarthritis of the hip and/or knee. The index consists of 24 questions (5 pain, 2 stiffness and 17 physical function) and can be completed in less than 5 minutes. The WOMAC is a valid, reliable and sensitive instrument for the detection of clinically important changes in health status following a variety of interventions (pharmacologic, surgical, physiotherapy, etc.).

In The Hip & Knee Registry, WOMAC results are reported as a normalized score. Individual question responses are assigned a score of between 0 (extreme) and 4 (None). Individual question scores are then summed to form a raw score ranging from 0 (worst) to 96 (best). Finally, raw scores are normalized by multiplying each score by 100/96. This produces a reported WOMAC Score of between 0 (worst) to 100 (best).

As of December 1996, 2124 THA patients participating in The Hip & Knee Registry had a mean preoperative WOMAC score of 44. This improved to 74 at 1 to 5 months and to 78 at 5 to 18 months after THA.

Interpretation of the significance of differences in mean WOMAC scores is largely determined by sample size and the size of the difference in scores between groups of patients. Any formal test of statistical significance of differences in WOMAC scores should include the advice of a statistician.

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This article  is a bit off  beat based on the question in that a femoral resurfacing is not exactly the subject of the question but its information.  Amazing that there are few studies on the general revision for the ASR.

J Bone Joint Surg Am. 2010 Jul 7;92(7):1600-4.

Functional results of isolated femoral revision of hip resurfacing arthroplasty.

Source

Robert Jones and Agnes Hunt Orthopaedic Hospital, Gobowen, Oswestry, Shropshire SY10 7AG, United Kingdom. drrobgilbert@aol.com

Abstract

BACKGROUND:

Conversion of a failed femoral resurfacing component is reportedly a straightforward procedure; however, little has been published regarding the functional results following revision. Our primary aim was to compare the functional results for a group of patients who had had isolated femoral component revision after a failed hip resurfacing with those for a group of patients with a surviving hip resurfacing. Our secondary aim was to identify whether the mode of failure affects functional outcome.

METHODS:

Between 1997 and 2002, data were prospectively collected on 5000 Birmingham Hip Resurfacing procedures. One hundred and seventy-seven hips were revised, and, of those, seventy-six had an isolated femoral component revision. We reviewed the modes of failure and the post-revision clinical outcomes for this subgroup (the revised implant group) and compared the results with those for the patients who had a surviving hip resurfacing implant (the surviving implant group).

RESULTS:

The median Harris and Merle d'Aubigné hip scores were significantly better in the surviving implant group than in the revised implant group (median Harris score, 96 compared with 82 [p < 0.001]; median Merle d'Aubigné score, 17 compared with 14 [p < 0.001]). When we analyzed outcomes following revision, we found that the mode of failure affected outcome. Patient satisfaction and clinical outcomes were worse following revision because of femoral component loosening in comparison with revision because of femoral neck fracture or revision because of femoral head collapse or osteonecrosis. In these three subgroups, the median Harris hip scores were 66, 87, and 92, respectively, and the median Merle d'Aubigné scores were 10, 14, and 15, respectively. Six of fifteen patients in the femoral loosening group believed that they were worse or much worse after the revision than they had been before the primary procedure, compared with four of twenty-five patients in the femoral neck fracture group and two of twenty-two patients in the femoral head collapse or osteonecrosis group. Four patients (four hips) experienced complications as a consequence of revision surgery (three deep infections and one case of loosening of an uncemented femoral stem).

[Merle d'Aubigné scores:  http://www.jbjs.org/data/Journals/JBJS/928/JBJA0890919860E01.pdf]

CONCLUSIONS:

The functional results for patients who had revision of the femoral component of a current-generation metal-on-metal resurfacing arthroplasty were worse than those for patients with a surviving hip resurfacing. Patients who had revision because of femoral component loosening had worse outcomes than those who had revision because of femoral neck fracture or femoral head collapse or osteonecrosis.






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