Arthritis of the Knee Is There a Role for Arthroscopic Debridement?

Robert Litchfield M.D., FRCSC, Associate Professor
John Gallagher, FRACS
Department of Surgery, Division of Orthopaedics
Fowler Kennedy Sport Medicine Clinic
University of Western Ontario
London, ON

Arthroscopy of the arthritic knee is a most rewarding treatment modality when used selectively in the carefully chosen and well-informed patient. The role of arthroscopic debridement in the arthritic knee is to provide pain relief and functional improvement and therefore postpone (and in many cases, avoid), other major surgical interventions such as corrective osteotomies or joint arthroplasties.

Arthroscopy is a valuable part of the treatment armamentarium for arthritis of the knee, and we should not allow its important role to be undermined by recent sensationalist claims based largely on a single scientifically challenged study by Moseley et al1.

Many authors have already highlighted some of the weaknesses of Moseleys study2, 3 and have questioned the validity of the conclusions. We at the Fowler Kennedy Sport Medicine Clinic feel it warranted to highlight three such criticisms to better substantiate the role of arthroscopy in the arthritic knee.

Firstly, Moseleys study employed questionable methodology for recruitment and assessment, with three different measures (Inclusion Criteria Visual Analogue Score, Sample Size SF36, Primary Outcome Knee Specific Pain Score) used disjointedly throughout the study.

The SF36, while being an excellent general population assessment tool, is most insensitive when performing specific comparisons, as was done here. Furthermore, the Knee Specific Pain Score (created by the study authors to facilitate their own study purposes) was used in place of the SF36 as the primary outcome measure and is felt by some to be invalid3.

Secondly, the study was designed as a superiority trial but when the results did not support this, was changed post-factum to an equivalence trial, resulting in the high likelihood of data-dependant biases4. Additionally, it has been shown to have inadequate power, well below the required level necessary to substantiate their claims of equivalence between Placebo, Arthroscopic Lavage and Arthroscopic Debridement.

Third and finally, Moseleys paper did not address the single most important issue in the role of arthroscopy of the arthritic knee patient selection. Quite the opposite in fact, as nearly half (44%) of those invited into the study refused to participate. Those participating had double the incidence of severe arthritis, and therefore were thus less likely to benefit from arthroscopy. This strong pre-selection bias further invalidates Moseleys conclusion of equivalence.

Knowing how to perform a particular operation well, while important, is secondary to knowing on whom to perform it. This, in our opinion, is the key to success in arthroscopy of the arthritic knee.

Three areas must be assessed when considering arthroscopy of the arthritic knee in order to increase the likelihood of a satisfactory outcome : 1. surgical indication factors; 2. patient-related factors and 3. surgery-related factors.

In many instances, knee arthroscopy will not be indicated, with other alternatives such as medical therapies, corrective osteotomy, unicompartmental or total knee arthroplasty being more appropriate (see Figure 1). We believe the following factors favour arthroscopic debridement of an arthritic knee:

Favourable Surgical Indication Factors

1. Mechanical Symptoms
2. Mechanical Signs
3. Moderate Effusion
4. Short Duration of Symptoms
5. Loose Bodies on X-ray

Favourable Patient-Related Factors
1. Normally Aligned Knee5
2. Stable Knee
3. Absence of Multiple Procedures
4. Low Grade Unicompartmental X-ray Changes
5. No Litigation / Insurance / Workers Compensation

Favourable Surgery-Related Factors
1. Unstable Meniscal Tear Removal / Repair
2. Unstable Articular Chondral Flap Removal / Repair
3. Loose Bodies Removal
4. Synovitis Limited Debridement
5. Bare Bone Avoidance of Abrasion Arthroplasty6

The role of arthroscopic debridement is thus limited and not applicable to all knee arthritis patients. Rather, consideration of favourable prognostic factors such as those listed above will assist in the appropriate selection of the patient most likely to benefit from an arthroscopic debridement.

Where these factors are ignored less than ideal knee arthritis patients will undergo arthroscopy with less favourable results.

Even when favourable surgical indications and patient variables exist, good outcome measures are not guaranteed, highlighting the need to not only take care in selecting the appropriate patient but also to assume responsibility for educating our patients about their diagnosis, proposed management and expected results. Thus to increase the likelihood of having a satisfied patient post-arthroscopy, a pre-arthroscopy education program should be conducted. The knee arthritis patient should be made aware of the following with respect to arthroscopic debridement:

1. A likelihood BUT no guarantee of symptomatic improvement
2. Unpredictable and limited gains determined by intraoperative findings
3. Any benefits achieved may be short-lived
4. A non-restorative / non-curative procedure
5. Quite possibly will need further future surgery (HTO, UKR, TKR)

This is a vital step to avoid the unrealistic expectations of some patients, including that of having a normal knee post-arthroscopy.

While many patients with an arthritic knee will be better managed by means other than arthroscopy, there is a deserving subgroup who will benefit from an arthroscopic debridement (Figure 2). These patients should not be denied the opportunity to have a gold standard level of care due to the negative press generated by one highly publicized, yet scientifically flawed paper1. Rather, these patients should be carefully selected and educated preoperatively before undergoing appropriate arthroscopic debridement surgery following which they can expect a high likelihood of significant improvement. This likelihood of experiencing a favourable outcome is substantiated by a large volume of clinical evidence7, 8, 9, 10, 11, 12, 13 which mirrors our personal experience here at the Fowler Kennedy Sport Medicine Clinic.

We look forward to shedding more light soon on this important topic with the anticipated completion of a randomized, controlled, evaluator-blinded, prospective study initiated by the late Dr. Sandy Kirkley assessing Arthroscopic Surgery versus Non-Surgical Treatment of Osteoarthritis of the Knee.

References

1. Moseley J.B. et al.: A controlled trial of arthroscopic surgery for osteoarthritis of the knee. N Engl J Med, 2002; 347(2): 81 88
2. Johnson L.L. Degenerative arthritis arthroscopy and research Letters to the Editor. Arthroscopy, 2002; 18(7): 683 686
3. Chambers K., Schulzer M., Sobolev B., Day B. Degenerative arthritis arthroscopy and research Letters to the Editor. Arthroscopy, 2002; 18(7): 686 687
4. Jones B., Jarvis P., Lewis J.A., Ebbutt A.F. Trials to assess equivalence: The importance of rigorous methods. BMJ, 1996; 313: 36 39
5. Harwin S.F. Arthroscopic debridement for osteoarthritis of the knee: Predictors of patient satisfaction. Arthroscopy, 1999; 15(2): 142 146
6. Bert J.M., Maschka K. The arthroscopic treatment of unicompartmental gonarthrosis: a five year follow up study of abrasion arthroplasty plus arthroscopic debridement and arthroscopic debridement alone. Arthroscopy, 1989; 5: 25 32
7. Merchan E.C.R., Galindo E. Arthroscope guided surgery versus nonoperative treatment for limited degenerative osteoarthritis of the femorotibial joint in patients over 50 years of age: A prospective comparative study. Arthroscopy, 1993; 9: 663 667
8. Jackson R.W., Rouse D.W. The results of partial arthroscopic meniscectomy in patients over 40 years of age. J Bone Joint Surg Br, 1982; 64: 481 485
9. Rand J.A. Role of arthroscopy in osteoarthritis of the knee. Arthroscopy, 1991; 7: 358 363
10. Spraque N.F. III. Arthroscopic debridement for degenerative knee joint disease. Clin Orthop, 1981; 160: 118 123
11. Rand J.A. Arthroscopic management of degenerative meniscus tears in patients with degenerative arthritis. Arthroscopy, 1985; 1: 253 258
12. Christie W.R., Spraque N.F. III, Kim L. Arthroscopic evaluation and treatment of the symptomatic previously operated knee. Arthroscopy, 1988; 4: 194 198
13. Aichroth P.M., Patel D.V., Moyes S.T. A prospective review of arthroscopic debridement for degenerative joint disease of the knee. Int Orthop, 1991; 15: 351 355

Legend

figure 1a litchfieldfigure 1b litchfield

Figure 1

A: Patient (X) with varus knee alignment
B: Patient (Y) with Grade IV Medial Compartment Gonarthrosis

Neither of these patients (X,Y) could be expected to have significant improvement with arthroscopic debridement alone candidates for HTO

figure 2a litchfieldfigure 2b litchfield

Figure 2

A: Patient (Z) with mild to moderate medial compartment degenerative arthritis
B: Patient (Z) with degenerative medial Parrot Beak meniscal flap tear

This patient (Z) could be expected to have a good result post arthroscopic debridement

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