JBJS | Arthroscopic Débridement of the Knee for Osteoarthritis in Patients Fifty Years of Age or Older : Utilization and Outcomes in the Province of Ontario

The Journal of Bone & Joint Surgery, Volume 84, Issue 1

Scientific Article | January 01, 2002

Arthroscopic Débridement of the Knee for Osteoarthritis in Patients Fifty Years of Age or Older : Utilization and Outcomes in the Province of Ontario

Eugene K. Wai, MD, MSc; Hans J. Kreder, MD, MPH, FRCS(C); Jack I. Williams, PhD

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Investigation performed by the Musculoskeletal Health Status Working Group, Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada

Eugene K. Wai, MD, MSc
Hans J. Kreder, MD, MPH, FRCS(C)
Division of Orthopaedic Surgery, Sunnybrook and Women’s College Health Sciences Centre, 2075 Bayview Avenue, Room MG-365, Toronto, ON M4N 3M5, Canada. E-mail address for E.K. Wai: euge.wai@utoronto.ca. E-mail address for H.J. Kreder: hans.kreder@swchsc.on.ca

Jack I. Williams, PhD
Institute for Clinical Evaluative Sciences, 2075 Bayview Avenue—G-Wing, Toronto, ON M4N 3M5, Canada. E-mail address: ji.williams@ices.on.ca

No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. No funds were received in support of this study.

The Journal of Bone & Joint Surgery. 2002; 84:17-22

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Abstract

Background: There is little available information regarding the effectiveness of arthroscopic knee débridement for the treatment of arthritis. The purpose of this study was to evaluate patterns of utilization of arthroscopic knee débridement and outcomes following that procedure for the treatment of degenerative arthritis in persons fifty years of age or older in the Province of Ontario.

Methods: All patients fifty years of age or older who underwent elective arthroscopic knee débridement for the treatment of degenerative arthritis between 1992 and 1996 were identified from administrative data sets. Surgical complications and subsequent knee replacements were noted. Population rates were compared across the sixteen District Health Council regions within Ontario. Outcomes were modeled as a function of patient age, gender, and comorbidity with use of multivariate regression analysis.

Results: We identified 14,391 eligible unilateral arthroscopic knee débridement procedures. There was a threefold difference in the population rate of arthroscopic débridement across geographic regions. Overall, 1330 (9.2%) of all patients required total knee arthroplasty within one year after the débridement. Of the 6212 patients with a minimum three-year follow-up, 1146 (18.4%) had undergone total knee replacement within three years following the débridement. Patients who were at least seventy years of age were 4.7 times more likely to have total knee arthroplasty within one year after the débridement than were those less than sixty years of age (19.0% compared with 4.0%; p < 0.05). Patients sixty years of age or older were more likely to have an early total knee replacement (within one year after the débridement) in District Health Council regions where the population rates of arthroscopic knee débridement were higher (p = 0.04).

Conclusions: The higher rates of early total knee arthroplasty and the significant relationship between rates of early total knee arthroplasty and rates of utilization suggest that arthroscopic débridement for the treatment of osteoarthritis of the knee may be overutilized in elderly patients. Important clinical issues such as patient preference, risk perception, and functional outcome cannot be addressed just with the administrative data used for this study.

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Introduction

Arthroscopy of the knee is safe and effective^1,2 and is the most common orthopaedic surgical procedure performed today^1-3. Arthroscopic treatment for traumatic disorders of the meniscus and the intra-articular ligaments has been well established⁴. More recently, arthroscopic débridement has been used to manage patients with degenerative knee arthritis, although there is little evidence documenting its efficacy for this purpose compared with that of medical management or joint replacement^5,6. In case series ranging in size from forty-three to 441 knees, success rates have ranged from 50% to 80% at two to four years^2,7-18. Because of small sample sizes, it is difficult to compare the outcomes of various subgroups, an analysis that could help to refine the specific indications for arthroscopic knee débridement. Furthermore, the majority of these reports are by academic specialists, which may limit the generalizability of the findings.

The purpose of this study was to evaluate patterns of utilization of arthroscopic knee débridement and outcomes following those procedures for the treatment of degenerative arthritis in the Province of Ontario as well as to identify patient-specific factors that were related to those outcomes.

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Fig. 1:: Age and gender-adjusted population rates (per 1000) of arthroscopic knee débridement by year.

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Fig. 2:: For each District Health Council (DHC), the age and gender-adjusted rate of arthroscopic knee débridement for persons sixty years of age or older was compared with the rate of subsequent total knee replacements within one year following arthroscopic débridement.

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Fig. 3:: For each District Health Council (DHC), the age and gender-adjusted rate of arthroscopic knee débridement for persons less than sixty years of age was compared with the rate of subsequent total knee replacements within one year following arthroscopic débridement.

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TABLE I: Number and Unadjusted Rate of Subsequent Operations Within One Year Following Arthroscopic Knee Débridement by Age Group

Procedure	50-59 Years Old (N = 6487)	60-69 Years Old (N = 5435)	70-79 Years Old (N = 2223)	80 Years Old (N = 246)
Knee arthroscopy	214 (3.3%)	131 (2.4%)	?50 (2.2%)	?4 (1.6%)
High tibial osteotomy	107 (1.6%)	?53 (1.0%)	??9 (0.4%)	?0 (0.0%)
Total knee replacement	261 (4.0%)	604 (11.1%)	422 (19.0%)	43 (17.5%)

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TABLE I: Number and Unadjusted Rate of Subsequent Operations Within One Year Following Arthroscopic Knee Débridement by Age Group

Procedure	50-59 Years Old (N = 6487)	60-69 Years Old (N = 5435)	70-79 Years Old (N = 2223)	80 Years Old (N = 246)
Knee arthroscopy	214 (3.3%)	131 (2.4%)	?50 (2.2%)	?4 (1.6%)
High tibial osteotomy	107 (1.6%)	?53 (1.0%)	??9 (0.4%)	?0 (0.0%)
Total knee replacement	261 (4.0%)	604 (11.1%)	422 (19.0%)	43 (17.5%)

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TABLE II: Number and Unadjusted Rate of Subsequent Operations Within Three Years Following Arthroscopic Knee Débridement by Age Group

Procedure	50-59 Years Old (N = 2918)	60-69 Years Old (N = 2354)	70-79 Years Old (N = 854)	80 Years Old (N = 86)
Knee arthroscopy	259 (8.9%)	159 (6.8%)	?53 (6.2%)	?7 (8.1%)
High tibial osteotomy	124 (4.2%)	?47 (2.0%)	??7 (0.8%)	?0 (0.0%)
Total knee replacement	283 (9.7%)	557 (23.7%)	279 (32.7%)	27 (31.4%)

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TABLE II: Number and Unadjusted Rate of Subsequent Operations Within Three Years Following Arthroscopic Knee Débridement by Age Group

Procedure	50-59 Years Old (N = 2918)	60-69 Years Old (N = 2354)	70-79 Years Old (N = 854)	80 Years Old (N = 86)
Knee arthroscopy	259 (8.9%)	159 (6.8%)	?53 (6.2%)	?7 (8.1%)
High tibial osteotomy	124 (4.2%)	?47 (2.0%)	??7 (0.8%)	?0 (0.0%)
Total knee replacement	283 (9.7%)	557 (23.7%)	279 (32.7%)	27 (31.4%)

Methods

Outcomes Study

All individuals, fifty years of age or older, undergoing arthroscopic knee débridement in Ontario between 1992 and 1996 were identified from the Ontario Health Insurance Plan (OHIP) Physician’s Claims database with the use of fee codes (Appendix). OHIP provides universal health-care coverage for the residents of Ontario, and it is estimated that 95% of physicians in Ontario are paid on a fee-for-service basis by OHIP. The OHIP database contains a unique identifier and demographic information for each patient as well as procedural and diagnostic codes for each procedure for which a bill was submitted. Although the procedural and demographic data are considered quite accurate, the diagnostic codes are considered vague and nonspecific¹⁹. The Canadian Institute for Health Information (CIHI) Discharge Abstracts database was used to supplement the OHIP information. CIHI collects information regarding inpatient and day-surgery discharges, including the International Classification of Diseases, Ninth Revision (ICD-9), diagnostic codes²⁰. Although CIHI uses the Canadian Classification of Procedures codes²¹, they are not detailed enough to distinguish between the different types of arthroscopy. Records from the OHIP database were linked to the CIHI database with use of patient health numbers and demographics to provide detailed information regarding procedures and diagnoses. Furthermore, the cohort was linked to the Ontario mortality file to obtain complete information regarding patient deaths.

To form the study cohort, an algorithm, similar to that used in previous research²² and based on the ICD-9 codes, was created to identify patients whose primary diagnosis was osteoarthritis. Patients with a diagnosis of inflammatory arthritis, such as rheumatoid arthritis, were excluded. Patients who had undergone a bilateral knee operation with both procedures performed on the same day were also excluded.

Gender and age at the time of the index procedure were abstracted from the CIHI database. The modified Charlson-Deyo index was used to adjust for comorbidity²³. This index is a well-validated scale that can be calculated from administrative data on the basis of certain diagnostic codes related to various disease states. The score has been shown to predict mortality and complication rates of patients treated with total joint replacement as well as the length of their stay in the hospital^22,24.

The algorithm^22,24 was also used to identify complications of the index arthroscopy from the CIHI database. These complications included infection, deep vein thrombosis, nerve or vessel injury, compartment syndrome, intraoperative surgical complications, and major medical complications. The complications were chosen on the basis of the importance of their effect on clinical outcome and their clarity (little potential for misclassification).

Subsequent specific surgical procedures on the knee (arthroscopy, high tibial osteotomy, and total knee arthroplasty) for a minimum of one year following the index surgery (up to 1997) were sought from the OHIP database, and the time to these subsequent surgical procedures was calculated. Since neither data set includes the side of the operation, it is possible that subsequent knee replacements were performed on the contralateral knee (that is, not the knee treated with the original arthroscopic débridement). In order to determine whether contralateral knee replacement is common following arthroscopic knee débridement, a chart review was undertaken at one institution. All patients who had undergone arthroscopic knee débridement for the treatment of arthritis between 1992 and 1996 followed by total knee replacement up to three years later were identified (with use of the same study inclusion criteria as had been used in the population study). Only one of twenty-one such patients had a total replacement of the contralateral knee.

Descriptive statistics for the entire study population were used to describe the rate of complications as well as the rate of subsequent surgical procedures within one and three years following the index arthroscopic knee débridement. The overall rates of complications and total knee arthroplasty (at one and three years) were calculated for individual demographic subgroups and compared with use of chi-square analysis or the Cochran-Armitage chi-square test for trend. A multivariate Cox proportional hazards model was fitted to determine the significance of the demographic factors as determinants of time to total knee arthroplasty after adjustment for all of the other confounding factors (age, gender, and comorbidity). Cox regression is appropriate for time-dependent continuous outcomes that cannot be modeled with use of simple linear regression. Prior to the multivariate analysis, steps were performed to ensure that models were fitted appropriately and that statistical assumptions were not violated^25,26.

Pattern of Utilization

The Province of Ontario is divided into sixteen District Health Councils (DHC) to which funding is allocated. For this analysis, each resident of Ontario was assigned to a DHC on the basis of the first three digits of their postal code. Age and gender-adjusted population rates of arthroscopic knee débridement for the treatment of arthritis were determined for the overall study period, for each year, and by DHC. Regional variation was quantified with use of the extremal quotient²⁷, the weighted coefficient of variation²⁸, and the systematic component of variation²⁹. The extremal quotient is the ratio of the rate of the DHC with the highest arthroscopy rate relative to that of the DHC with the lowest arthroscopy rate. The coefficient of variation measures the ratio of the standard deviation of the utilization rates across the sixteen DHCs to the mean DHC utilization rate weighted by the population at risk in each DHC. This takes into account the unequal population sizes of the DHCs. The systematic component of variation measures variations in DHC utilization rates after adjustment for random variations in utilization. Chi-square tests were used to test for significant deviation of individual DHC rates from the provincial rate over the four-year study period. A significance level of p < 0.003 (approximately 0.05/16) was chosen to take into account multiple comparisons with use of a Bonferroni adjustment³⁰.

It was hypothesized that regions with excessively high population rates of arthroscopic knee débridement would have higher rates of early total knee arthroplasty following débridement. To test this hypothesis, we evaluated the correlation between the age and gender-adjusted population utilization rates of arthroscopic débridement with the age and gender-adjusted population utilization rates of early total knee arthroplasty following arthroscopic débridement for each DHC. To determine if this trend was more pronounced in older patients, separate Pearson correlation coefficients were calculated for individuals over and under the age of sixty. The age of sixty was chosen (somewhat arbitrarily) as the age when total knee arthroplasty is considered for the treatment of osteoarthritis.

Results

Outcomes Study

A total of 14,391 unilateral arthroscopic débridement procedures for the treatment of osteoarthritis of the knee were performed on residents fifty years of age or older in the Province of Ontario between 1992 and 1996. A minimum of one year of follow-up data were available for all patients, and a minimum of three years of follow-up data were available for 6212 of them. The average age was 62.4 years (range, fifty to ninety-two years), 7210 (50.1%) of the patients were male, 13,743 (95.5%) had no comorbidity, and seventy-two (0.5%) had a Charlson-Deyo score of 2.

Overall, there were sixty-seven surgical complications (0.5%), including nerve or vessel injury, compartment syndrome, and other intraoperative mishaps. We identified forty medical complications such as stroke and myocardial infarction (0.3%), eighty deep-vein thromboses (0.6%), sixty-nine infections (0.5%), and eighteen deaths (0.1%) within three months following the arthroscopic débridement. The total complication rate therefore was 274 (1.9%) of 14,391. The complication rate increased with advancing age. The two hundred and forty-six individuals at least eighty years of age had a total of eight complications (3.3%), including two deaths (0.8%) and three infections (1.2%).

Within one year after the index arthroscopic débridement, 399 individuals (2.8%) underwent a second arthroscopic débridement, 1330 (9.2%) underwent total knee arthroplasty, and 169 (1.2%) underwent high tibial osteotomy. Within three years after the index arthroscopic débridement, 478 (7.7%) of the 6212 patients with a minimum of three years of follow-up had a repeat arthroscopy, 1146 (18.4%) had a total knee arthroplasty, and 178 (2.9%) had a high tibial osteotomy.

The rate of total knee arthroplasty at both one and three years increased significantly (p = 0.0001) with age (Tables I and II). A person who was at least seventy years of age was 4.7 times (95% confidence interval, 4.0 to 5.5 times) more likely to undergo total knee replacement at one year following arthroscopic knee débridement than was a person fifty to fifty-nine years of age (Table I). Three hundred and six (33%) of the 940 persons who were at least seventy and had a minimum of three years of follow-up underwent total knee replacement within three years after the index arthroscopic débridement compared with 283 (10%) of the 2918 persons between the ages of fifty and fifty-nine years (Table II). The trend for higher rates of total knee arthroplasty with increasing age remained significant when adjusted for gender and comorbidity with use of a multivariate Cox proportional hazards model (p = 0.02). Neither gender nor comorbidity was a significant determinant of the need for repeat operations in the unadjusted or adjusted analysis (p > 0.05).

Pattern of Utilization

On the average, 1.4 arthroscopic débridements were performed annually per 1000 population across the Province of Ontario between 1992 and 1996. The age and gender-adjusted population rates increased significantly (p = 0.001) with each year over the study period, at an average rate of 10.1% per year (Fig. 1).

Population rates of arthroscopic knee débridement ranged from 0.7 to 2.3 persons per 1000 (extremal quotient = 3.1) across the District Health Councils of Ontario. The coefficient of variation was 29.0, and the systematic component of variation was 78.9.

The age and gender-adjusted rates of early total knee arthroplasty (within one year following arthroscopic débridement) ranged from 3.0% to 13.7% for all age groups studied across the District Health Councils in the Province of Ontario. Higher population rates of arthroscopic knee débridement were associated with higher rates of early total knee replacement in patients sixty years of age or older (r = 0.52, p = 0.04) (Fig. 2). There was no significant relationship (r = 0.21, p = 0.4) for individuals under the age of sixty (Fig. 3).

Discussion

The use of arthroscopic débridement for the treatment of arthritis remains controversial, and its efficacy has not been demonstrated by high-quality trials⁶. One of the goals of treatment is to delay the need for total knee arthroplasty by controlling symptoms¹⁵. McLaren et al. noted that six (3.5%) of 170 individuals between the ages of twenty-three and eighty-two years (mean age, fifty-four years) required total knee replacement within two years after arthroscopic débridement¹⁵. Older patients with more advanced knee joint arthritis may benefit less from arthroscopic débridement. Goldman et al. reviewed eight published case series consisting of a total of 678 patients who had been followed for an average of thirty-eight months (range, fourteen to sixty months) after arthroscopic débridement for the treatment of osteoarthritis³¹. On the average, 68% of the patients had a good result, which was generally defined by the authors as relief of pain. Poor results were noted to be associated with advanced arthritis^9,11,16,18, malalignment^9,16,18, and nonmechanical symptoms unrelated to meniscal tears or cartilage flaps¹⁶. We found that one-third of individuals seventy years of age or older underwent total knee replacement within three years following arthroscopic débridement. While this implies that up to two-thirds of these individuals may have derived long-term benefit from the débridement, an alternative view is that one-third of the patients were poorly selected for arthroscopic débridement. As physicians gain experience with a technique, the indications are often broadened to include patients who are less likely to benefit before the most appropriate indications are elucidated³². The finding that early knee replacement was more likely to be required for patients who were at least seventy in regions with higher population rates of arthroscopic débridement further supports the view that débridement may be overutilized in these patients. Given the documented success of total knee arthroplasty in this age group^24,33,34, the use of arthroscopic débridement may be unnecessarily delaying total knee replacement in elderly patients.

Four hundred and seventy-eight (7.7%) of the 6212 individuals with a minimum of three years of follow-up underwent repeat arthroscopic knee débridement within three years (Table II). This finding suggests that these individuals were sufficiently satisfied with the first operation to have the procedure again, on either the same or the contralateral knee. Repeat arthroscopic débridement within one year was much less common, especially in older individuals (Table I).

To the best of our knowledge, the present study represents the first attempt to evaluate, with use of administrative data, the results of all arthroscopic débridements performed for the treatment of knee arthritis within an entire geographic population. Our study provides sufficient numbers for subgroup analysis and ensures essentially complete follow-up. However, an analysis based on administrative data is limited by the type and quality of the data in the database. Important clinical variables such as patient preference, risk perception, and functional outcome are not available in the data sets that we used. While procedural and demographic data have been shown to be accurate in the CIHI database³⁵, comorbidity and complications tend to be undercoded. Also, since the side of a procedure is not coded in the administrative databases used for this study, the reported rate of subsequent knee replacements would be inflated if a large number of these operations were in fact performed on the contralateral knee. However, a chart review at one institution indicated that this is unlikely.

In conclusion, this population-based effectiveness study demonstrated that arthroscopic débridement of the knee for the treatment of osteoarthritis is a safe procedure with low complication rates, although the risk of complications increases with advancing age. The rates of subsequent operations can be discussed with patients when surgeons counsel them preoperatively. The rate of early total knee arthroplasty following arthroscopic débridement rises significantly with age, and this should be taken into consideration when deciding who is a candidate for this procedure. Future investigators should consider patient preference, risk perception, and functional outcomes, which could not be addressed with use of the data available in the present study.

Appendix

Ontario Health Insurance Plan (OHIP) Fee Codes for Arthroscopic Débridement, Total Knee Arthroplasty, and High Tibial Osteotomy

R204: Knee arthroscopy, débridement, one compartment

R205: Knee arthroscopy, débridement, more than one compartment

R206: Knee arthroscopy, abrasion arthroplasty

R441: Total knee replacement

R289: Tibial osteotomy

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Fig. 1:: Age and gender-adjusted population rates (per 1000) of arthroscopic knee débridement by year.

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TABLE I: Number and Unadjusted Rate of Subsequent Operations Within One Year Following Arthroscopic Knee Débridement by Age Group

Procedure	50-59 Years Old (N = 6487)	60-69 Years Old (N = 5435)	70-79 Years Old (N = 2223)	80 Years Old (N = 246)
Knee arthroscopy	214 (3.3%)	131 (2.4%)	?50 (2.2%)	?4 (1.6%)
High tibial osteotomy	107 (1.6%)	?53 (1.0%)	??9 (0.4%)	?0 (0.0%)
Total knee replacement	261 (4.0%)	604 (11.1%)	422 (19.0%)	43 (17.5%)

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TABLE I: Number and Unadjusted Rate of Subsequent Operations Within One Year Following Arthroscopic Knee Débridement by Age Group

Procedure	50-59 Years Old (N = 6487)	60-69 Years Old (N = 5435)	70-79 Years Old (N = 2223)	80 Years Old (N = 246)
Knee arthroscopy	214 (3.3%)	131 (2.4%)	?50 (2.2%)	?4 (1.6%)
High tibial osteotomy	107 (1.6%)	?53 (1.0%)	??9 (0.4%)	?0 (0.0%)
Total knee replacement	261 (4.0%)	604 (11.1%)	422 (19.0%)	43 (17.5%)

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TABLE II: Number and Unadjusted Rate of Subsequent Operations Within Three Years Following Arthroscopic Knee Débridement by Age Group

Procedure	50-59 Years Old (N = 2918)	60-69 Years Old (N = 2354)	70-79 Years Old (N = 854)	80 Years Old (N = 86)
Knee arthroscopy	259 (8.9%)	159 (6.8%)	?53 (6.2%)	?7 (8.1%)
High tibial osteotomy	124 (4.2%)	?47 (2.0%)	??7 (0.8%)	?0 (0.0%)
Total knee replacement	283 (9.7%)	557 (23.7%)	279 (32.7%)	27 (31.4%)

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TABLE II: Number and Unadjusted Rate of Subsequent Operations Within Three Years Following Arthroscopic Knee Débridement by Age Group

Procedure	50-59 Years Old (N = 2918)	60-69 Years Old (N = 2354)	70-79 Years Old (N = 854)	80 Years Old (N = 86)
Knee arthroscopy	259 (8.9%)	159 (6.8%)	?53 (6.2%)	?7 (8.1%)
High tibial osteotomy	124 (4.2%)	?47 (2.0%)	??7 (0.8%)	?0 (0.0%)
Total knee replacement	283 (9.7%)	557 (23.7%)	279 (32.7%)	27 (31.4%)