Provider Volume of Total Knee Arthroplasties and Patient Outcomes in the HCUP-Nationwide Inpatient Sample.

BACKGROUND The relationship between volume and outcome of total knee arthroplasties has never been evaluated in a nationally representative sample, to our knowledge. We hypothesized that surgeons and hospitals with higher patient volumes would have better outcomes, as defined by lower mortality rates, shorter hospital stays, and lower postoperative complication rates. METHODS The 1997 Healthcare Cost and Utilization Project (HCUP) Nationwide Inpatient Sample, Release 6, provided discharge abstracts of patients undergoing total knee arthroplasty from a national stratified probability sample. Logistic and multiple regression models were used to estimate the adjusted association of surgeon or hospital volume with rates of in-hospital mortality, pulmonary thromboembolism, deep venous thrombosis in the lower extremity, and postoperative wound infection as well as length of hospital stay. Estimates were calculated for a target population of 277,550 patients. Models were adjusted for comorbidity, age, gender, race, household income, and procedure (primary or revision arthroplasty). RESULTS The patients were mostly white (70.2%) and female (62.7%), with a mean age of 68.9 years. The overall in-hospital mortality rate for the target population was 0.2%, and the average length of stay was 4.6 days for the primary total knee arthroplasties and 4.9 days for the revision procedures. Surgeon volumes of at least fifteen procedures per year and hospital volumes of at least eighty-five per year were significantly and linearly associated with lower mortality rates (odds ratio = 0.56 [0.24 to 1.31] for surgeon volume of > or = 60). No other association demonstrated a significant and directionally consistent linear trend for improved outcomes. CONCLUSION Patients treated by providers with lower caseload volumes had higher rates of mortality following total knee arthroplasty in 1997. Proposing volume standards could decrease patient mortality following this procedure.

[1]  R. Deyo,et al.  Adapting a clinical comorbidity index for use with ICD-9-CM administrative databases. , 1992, Journal of clinical epidemiology.

[2]  J. Williams,et al.  Are complication rates for elective primary total hip arthroplasty in Ontario related to surgeon and hospital volumes? A preliminary investigation. , 1998, Canadian journal of surgery. Journal canadien de chirurgie.

[3]  C. Lavernia,et al.  Relationship of surgical volume to short-term mortality, morbidity, and hospital charges in arthroplasty. , 1995, The Journal of arthroplasty.

[4]  J. Concato,et al.  A simulation study of the number of events per variable in logistic regression analysis. , 1996, Journal of clinical epidemiology.

[5]  G. Forrest,et al.  Decreasing length of stay after total joint arthroplasty: effect on referrals to rehabilitation units. , 1999, Archives of physical medicine and rehabilitation.

[6]  V. Robertson,et al.  Hospital stay and discharge outcomes after knee arthroplasty. , 2001, Journal of quality in clinical practice.

[7]  Ross Ihaka,et al.  Gentleman R: R: A language for data analysis and graphics , 1996 .

[8]  E. DeLong,et al.  Relationship between physician and hospital coronary angioplasty volume and outcome in elderly patients. , 1997, Circulation.

[9]  D. Dennis,et al.  Relationship between mortality rates and hospital patient volume for Medicare patients undergoing major orthopaedic surgery of the hip, knee, spine, and femur. , 1997, The Journal of arthroplasty.

[10]  D. Heck,et al.  Patient Outcomes After Knee Replacement , 1998, Clinical orthopaedics and related research.

[11]  E. Hannan,et al.  Relationship between provider volume and mortality for carotid endarterectomies in New York state. , 1998, Stroke.

[12]  J. Benichou,et al.  An alternative test for trend in exposure-response analysis. , 1998, Journal of exposure analysis and environmental epidemiology.

[13]  R Poss,et al.  Association Between Hospital and Surgeon Procedure Volume and Outcomes of Total Hip Replacement in the United States Medicare Population* , 2001, The Journal of bone and joint surgery. American volume.

[14]  Edward L. Hannan,et al.  Investigation of the Relationship Between Volume and Mortality for Surgical Procedures Performed in New York State Hospitals , 1989 .

[15]  D. Fisher,et al.  Effect of a patient management system on outcomes of total hip and knee arthroplasty. , 1997, Clinical orthopaedics and related research.

[16]  M. Swiontkowski,et al.  Relationship between the Volume of Total Hip Replacements Performed by Providers and the Rates of Postoperative Complications in the State of Washington* , 1997, The Journal of bone and joint surgery. American volume.

[17]  C. Lang.  Comparison of 6- and 7-day physical therapy coverage on length of stay and discharge outcome for individuals with total hip and knee arthroplasty. , 1998, The Journal of orthopaedic and sports physical therapy.

[18]  M. R. Mölken,et al.  Statistical analysis of cost outcomes in a randomized controlled clinical trial. , 1994 .

[19]  V. Kim,et al.  Epidemiology of venous thromboembolic disease. , 2001, Emergency medicine clinics of North America.

[20]  C. Lavernia.  Hemiarthroplasty in hip fracture care: effects of surgical volume on short-term outcome. , 1998, The Journal of arthroplasty.

[21]  A. Planès,et al.  Risk of deep-venous thrombosis after hospital discharge in patients having undergone total hip replacement: double-blind randomised comparison of enoxaparin versus placebo , 1996, The Lancet.

[22]  S Greenland,et al.  Tests for trend and dose response: misinterpretations and alternatives. , 1992, American journal of epidemiology.

[23]  N. Scott,et al.  Influence of volume of work on the outcome of treatment for patients with colorectal cancer , 1999, The British journal of surgery.

[24]  E L Hannan,et al.  Coronary angioplasty volume-outcome relationships for hospitals and cardiologists. , 1997, JAMA.