arthroscopic synovectomy of the knee for rheumatoid arthritis

Arthroscopy: The Journal of Arthroscopic and Related Surgery 7( 1):91-97 Published by Raven Press. Ltd. 0 1991 Arthroscopy Association of North America

Arthroscopic Synovectomy of the Knee for Rheumatoid Arthritis

D. J. Ogilvie-Harris and A. Basinski

Summary: Arthroscopic synovectomy for rheumatoid arthritis was carried out on a total of 96 knees. The period of follow-up observation varied from 2 to 4 years. The technique was without major complication. There were statistically significant decreases in pain and synovitis over the 4-year follow-up time. The range of movement was maintained. Arthroscopic synovectomy was at least a valuable palliative procedure for uncontrolled synovitis of the knee. Key Words: Synovectomy-Pain-Rheumatoid arthritis-Synovitis.

Ablation of the synovium in the knee of the patient with rheumatoid arthritis can at least tempo- rarily control the disease. Trials in the United King- dom and in the United States indicated that in early stages of the disease, satisfactory results can be obtained. In the Arthritis Foundation Committee Multi-Centre Study of synovectomy and rheumatoid arthritis, joint swelling was found to be significantly decreased 3 years after synovectomy, but the pain relief of medical treatment was equal to that provided by synovectomy (1). More recent studies have indicated that the long-term results of synovectomy in uncontrolled studies are signiti- cantly reduced pain and recurrent effusions after open synovectomy (2.3).

There are risks associated with open synovectomy. The patients require a hospital stay of 7-10 days. After open synovectomy they often lose range of movement and require subsequent manip- ulations. Despite some initial loss of range of movement, the long-term studies indicate that after open

From the Departments of Orthopaedic Surgery (D.J.O-H) and Family and Community Medicine (A.B.), Family Medicine Cen- tre, Toronto Western Hospital, and University of Toronto, To- ronto, Ontario, Canada.

Address correspondence and reprint requests to Dr. D. J. Ogil- vie-Harris, Orthopaedic Surgery, Toronto Western Hospital. Room I-221, Fraser Fell Pavilion. 399 Bathurst St.. Toronto, Ontario M5T 2S8. Canada.

The technique described in this article will be demonstrated in a forthcoming Video Supplement to Arthroscopy.

surgical synovectomy. range of movement is rela- tively well preserved.

Arthroscopic synovectomy is a recently devel- oped technique for surgical ablation of the synovium of the knee joint. In skilled hands it in- volves minimal morbidity for the patient (4,5). The purpose of this study was to determine if this technique was of benefit in rheumatoid arthritis of the knee.

SURGICAL TECHNIQUE

Arthroscopic synovectomy was performed using an arthroscope attached to a video display. A tour- niquet was used in all patients. All patients received a general anesthetic. The power shaver system used 55mm full-radius resectors. In most cases a pres- sure irrigation system was used but gravity flow was adequate. The inflow was through the arthroscope portal and outflow through the shaver. The irrigation fluid was normal saline solution.

Arthroscopic synovectomy was carried out in a systematic manner after examination and evaluation of the joint. Using the shaver, the superficial layers of the synovium are removed. There is usually a defining plane between the synovium and the subsynovial tissues. Resection is carried down to this plane. When sufficient synovium has been removed, the smooth, shiny fibers of the capsule can be visualized and the superficial capillaries lying over the interior of the capsule can clearly be seen.

91

92 D. J. OGILVIE-HARRIS AND A. BASINSKI

To remove this quantity of synovium, it takes between 1 and Ifi h of operating time. Disposable synovial resector blades are the most effective means for ablating the tissue.

Step 1 The arthroscope was introduced through the an-

terolateral portal (Fig. 1). The shaver was introduced through the superolateral portal. The advan- tage of this approach is to clear the synovium from the superopatellar pouch before proceeding with the rest of the joint. Synovium can be resected from most of the superopatellar pouch and the lateral gutter.

Step 2 The arthroscope was left in the anterolateral por-

tal and the shaver was introduced through the ar- teromedial portal (Fig. 2). From this approach the medial gutter, the medial side of the joint, the inter- condylar notch, and a large portion of the lateral side of the joint can be reached. This approach can also be used to remove the synovium from the un- dersurface of the fat pad and the retropatellar area.

Step 3 The arthroscope is moved to the anteromedial

portal (Fig. 3). The shaver is placed in the anterolateral portal. From this approach the lateral side of the joint can be reached and cleared of synovium. The lower part of the lateral gutter, the intercondy- lar notch, and the medial joint can be visualized and treated.

FIG. 1. Step 1. The arthroscope (represented by the eye) is introduced into the anterolateral portal. The shaver is introduced into the lateral suprapatellar pouch. The shaded area represents the synovium that can be reached by the shaver.

FIG. 2. Step 2. The shaver is changed to the anteromedial portal; the arthroscope is left in the anterolateral portal. The shaded area represents the synovium that can be reached by the shaver.

Step 4 The arthroscope is left in the anteromedial portal

(Fig. 4). The shaver is introduced into the supero- medial portal. Through this approach the rest of the synovium in the suprapatella pouch and the inter- condylar notch can be removed as well as any re- maining synovium underneath the patellar tendon and in the medial gutter.

Step 5 The last part of the procedure consists of remov-

ing the synovium from the posterior aspect of the joint (Fig. 5). Considerable experience is necessary to avoid damage to the posterior structures of the knee. It is essential that the knee is in the flexed

FIG. 3. Step 3. The arthroscope is changed to the anteromedial portal and the shaver to the anterolateral portal. The shaded area represents the synovium that can be reached by the shaver.

Arthroscopy, Vol. 7, No. 1, 1991

KNEE SYNOVECTOMY FOR RHEUMATOID ARTHRITIS 93

FIG. 4. Step 4. The arthroscope is kept in the anterolateral portal. The shaver is moved up to the medial suprapatellar portal to complete the synovectomy anteriorly. The shaded area represents the synovium that can be reached by the shaver.

position and is distended. With the arthroscope still in the anteromedial portal after step 4, the posteromedial aspect of the joint can be visualized and the needle inserted into the posteromedial aspect of the joint. Having defined the portal, the shaver can then be introduced into the posteromedial section of the joint. If visualization of the posteromedial portion of the joint is not clear with the arthroscope in the anteromedial portal, then the arthroscope can also be introduced into the posteromedial compartment first and the shaver introduced approximately 2 cm below the arthroscope.

FIG. 5. Step 5. The posterior aspects of the joint are visualized last. The arthroscope and shaver may be introduced posteriorly (medial or lateral) or the shaver may be introduced posteriorly under direct vision from an anterior portal. Special techniques are necessary to safely resect synovium from the posterior com- partments (see text).

The lateral compartment is cleared in the same way, although the shaver will be visualized using an arthroscopic portal at the anterolateral portion of the joint.

It is essential to visualize the tip of the shaver at all times during procedures at the posterior aspect of the joint. The shaver will only resect synovium when the suction is on. It is therefore easy to control the rate of resection by controlling the suction rather than switching the shaver itself on and off. Using this technique, the shaver is left continuously running while the assistant controls the suction in response to the surgeon’s request. This technique allows resection of the synovium with minimal risk of damage to the neurovascular structures by pen- etrating the posterior capsule.

Postoperatively, a large suction drain was left in the knee joint for 2-4 h. The knee was wrapped in a tensor bandage. The patient was allowed full weight bearing on the same day of surgery. The patient was encouraged to perform quadriceps exercises and knee flexion exercises immediately postoperatively. The patient is usually discharged the day following surgery unless there were medical problems.

PATIENTS

Patients were selected for arthroscopic synovectomy of the knee when they had a minimum of 6 months persistent effusion and synovitis despite medical therapy. All patients fulfilled the American Rheumatological Association criteria for definite or classical rheumatoid arthritis and were functional class I or II. No attempt was made to standardize the patient’s medical treatment before or after the surgical procedure, and this was left in the control of the referring rheumatologist.

Initially there were 111 patients in the study. However, 17 were unavailable for follow-up observation (due to inability to contact the patients), leaving 96 available for study. There were 79 women and 17 men. The age distribution is dis- played in Table 1; the majority of patients were 3O- 60 years old. The grading of the articular cartilage lesions was according to the system set out by Out- erbridge (6).

The criteria for assessment of results were mod- ified from those proposed by Laurin et al. (7). The assessments were made preoperatively at 1, 2, 3, and 4 years postoperatively (Table 2). There were a total of 96 patients in the l- and 2-year group for follow-up observation. There were 52 patients in

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94 D. J. OGILVIE-HARRIS AND A. BASINSKI

TABLE 1. Age distribution of patients

No. of patients

Age, yr 20-29 30-39 40-49 50-59 60+

Total

8 29 32 18 9

96

the 3-year follow-up group. There were 33 patients in the 4-year follow-up group. During the period of follow-up observation, four patients underwent total joint replacement, one at 2 years, one at 3 years, and two at 4 years after surgery.

STATISTICAL METHODS

The outcomes of primary interest were the change in the indicators of clinical status. The clinical status was assessed on four dimensions: pain, synovitis and effusion, range of motion, and functional capacity. Each clinical measurement was rated on a 4-point ordinal rating scale (the score) representing the severity of the individual dimension (Table 2).

This patient population constitutes a single prospective cohort undergoing the surgical procedure. It was not possible to completely control for the phenomenon of regression to the mean. This could occur, for instance, in the event that patients are selected for surgery at a point of maximal decline in their clinical status. Hence, any perceived improvement in their clinical status after surgery could not solely be attributed to the surgical procedure. Yearly follow-up data for 1-4 years following surgery are available for 96 patients. By representing the score for each dimension of clinical status at the times of observation as a Markov process, we are able to compare the changes at the time of surgery

TABLE 2. Results

Results rating, points

0 1 2 3

Pain Severe Moderate Slight None Synovitis

effusion Severe Moderate Slight None Range of

motion >20% loss la-20% loss 040% loss 0% loss Functional Minimal Some Most All

capacity activity activity activities activities


with those during the follow-up periods @).I Thus, while not completely correcting the problems due to the lack of comparison control group, we are able to compare the changes before and after surgery on a more equal footing.

The data for each patient are represented as four sequences of measurements, one for each clinical evaluation. Each sequence has length correspond- ing to the number of follow-up observations available for that patient in addition to the preoperative assessment. Thus, there exist separate sequences of variable length for each clinical measurement, representing the ranges in clinical state presurgery and at least 2-year postsurgery follow-up assessments.

The Markov transition probablities were esti- mated from these data. Initially, the transition probabilities for the follow-up periods were tested for a stationary outcome (8). For pain, synovitis, and range of movement the hypothesis of a stationary outcome was not rejected (p = 0.05). In these cases of stationary outcomes, the follow-up data for each clinical measurement were pooled to estimate the transition probabilities postsurgery. They were then compared with the presurgery to postsurgery transition for stationary outcome (Table 3). Pain and synovitis exhibited significant differences between the transitions during the times before and after surgery and those experienced in the l-4 year postoperative period. In the case of range of motion, the follow-up assessments exhibited no change in clinical measurement for any patient at any time. The functional status exhibited a nonstationary outcome in postsurgical follow-up observation, largely due to a single marked improvement from mild functional impairment to none between the 2nd and 3rd years of follow-up observation (Table 4). Both the initial follow-up data and the transitions between years 2-3 were utilized for comparison. The transition between years 2-3 compared to the transition at surgery is not statistically different in the case of functional status. Patients had an improvement between the preoperative and year I assesments similar to the improvement from years 2 to 3 (without surgery during the latter). Improvements in clinical state following surgery, compared with those that might be expected in a single year of follow-up observation for a similar cohort as those who had surgery, are unequivocally demonstrated only for the clinical measures of pain and synovitis.

’ The Markov process is covered in depth by Bishop et al. in reference 8.


TABLE 3. Stationary outcome presurgery and postsurgety

Stationary outcome.

postoperative

Pain Yes Synovitis Yes Function No Motion Yes Overall Yes P+S+M Yes

Surgery, P postoperative

Average distribution

of states, P preoperative


of states, postoperative

0.9 No 0.35 No

<O.Ol No 1.0 No 0.67 No 1.0 No

-co.01 1.32 2.07 <O.Ol 0.77 2.24 CO.01 1.23 2.22

0.01 2.68 2.71 CO.01 2.22 3.83 CO.01 2.22 2.82


of states in I yP

1.38 0.73 I .32 (2.42jb 2.68 2.25 2.12

Difference

90.001 eo.001 @O.OOl (0.10)

0.38 90.001 <O.OOl

All signiticance tests are by likelihood ratio chi-squared. The scale for each clinical component is on O-3 and that for the overall index is O-5, obtained by pairwise grouping of the achieved

categories; similarly the P + S + M scale is on a scale of W. 0 The preoperative distribution of states, 4 is transformed by the Markov transition matrix P to yield the distribution of states qP that

might be expected in 1 year. This is used to estimate the corrected average state after 1 year. ’ Preoperative to postoperative transition compared between years l-2 and years 2-3.

The phenomenon of overall clinical improvement may be tested by comparing the difference in average clinical scores before and after surgery with the difference that would be experienced by a cohort with the same distribution of clinical scores as the presurgery cohort in a year of follow-up observation. Clinical improvement after surgery with a significant difference is demonstrated for pain and synovitis. The significance level of these findings is sufficiently high that the results remain significant even with stringent corrections for multiple comparisons. Although improvement is initially demon- strable for functional status compared to the first follow-up year, similar improvements were wit- nessed in the 2nd year of follow-up observation for this group. The change in function status may not be due to surgery alone (Table 3).

The indices of overall status (sum of clinical scores) and of the sum of pain, synovitis, and motion are also stationary postoperatively, so the data may be pooled for comparisons. They demonstrate a statistically significant improvement following the surgical event.

RESULTS

The blood loss after the procedure ranged from 50 to 400 ml. No patient required a transfusion. The average was approximately 100 ml of blood.

There were no infections or other serious compli- cations. One patient in the series had marked stiffening of the knee with a range of movement of 30-60” only and went on to total knee replacement subsequently.

Pain Whereas 56% of patients had severe or moderate

pain preoperatively, only 21% of patients had such

pain postoperatively at 4 years (Table 4). The average preoperative score was 1.32 and the average postoperative score was 2.07. The average score for a population initially distributed similarly to the preoperative population would be 1.38 after 1 year of follow-up observation. Thus, the arthroscopic synovectomy produced a statistically significant re- duction in pain even when controlled for the change in distribution of the postoperative clinical status.

Synovitis Preoperatively there were no patients without

synovitis, as the selection criteria for this procedure included the presence of persistence synovitis (Ta- ble 5). Eighty-six percent of patients had severe or moderate synovitis. Postoperatively at 4 years only 24% of patients had moderate or severe synovitis. Forty-two percent of patients had no synovitis or effusion whatsoever. The average preoperative score was 0.77, reflecting the selection criteria. The postoperative score was 2.24. At 4 years the postoperative score was 2.09. The average score for a matched preoperative cohort after 1 year of follow- up observation would be 0.73. Again, synovectomy

TABLE 4. Pain

Pain, no. of patients (%I

Preoper- atively 1 Yr 2 Yr 3 Yr 4 Yr

Total % % 96 52 33

Severe 17 (18) 1 (1) - 2 (2) 1 (2) 2 (6) Moderate 36 (38) 21 (22) 21 (22) 8 (15) 5 (15) Mild 38 (40) 44 (46) 47 (49) 28 (54) 19 (58) None 5 (5) 30 (31) 26 (27) 15 (29) 7 (21) Average 1.32 2.07” 2.01” 2.10” 1.94”

LI Statistically significant difference, p < 0.001, Average. average score based on points in Table 2.

Arthroscopy. Vol. 7. No. 1. 1991

D. J. OGILVIE-HARRIS AND A. BASINSKI

TABLE 5. Synovitis

Synovitis, no. of patients (%)


Total 96 96 96 52 33

Severe 35 (36) 5 (5) 8 (8) 6 (12) 3 (9) Moderate 48 (50) 12 (13) 10 (IO) 8 (15) 5 (15) Mild 13 (14) 34 (35) 46 (48) 17 (33) 11 (33) None 0 (0) 45 (47) 32 (33) 21 (40) 14 (42) Average 0.77 2.24” 2.06a 2.02” 2.09”

a Statistically significant difference, p < 0.001. Average, see explanation Table 4.

appears to have significantly improved this clinical outcome.

Functional assessment Preoperatively, 62% of patients had severe or

moderate functional impairment (Table 6). Postop- eratively at 4 years, only 18% of patients had such impairment. The average preoperative score was 1.23 and at 4 years it was 2.48. However, there was a single marked improvement in functional status from years 2 to 3. Although the patients overall showed a significantly increased functional status, it would not be attributed to surgery alone.

Range of movement Preoperatively, there were no patients with se-

vere loss of range of movement (Table 7). Seventy- one percent of patients had minimal loss of range of movement. Postoperatively, the range of movement was maintained. However, one patient did have severe stiffening of the knee. Overall, arthroscopic synovectomy did not cause significant loss of the range of movement of the knee, nor did it improve it.

Overall scores The maximum overall score of 12 was never

achieved. The range of overall scores was reduced by grouping the states into six categories, O-5 cor-

TABLE 6. Functional impairment

Functional impairment, no. of patients (%)


Total 96 96 96 52 33

Severe 18 (19) 2 (2) 2 (2) 1 (2) 1 (3) Moderate 41 (43) 15 (16) 16 (17) 6 (12) 5 (15) Mild 34 (35) 38 (40) 39 (41) 3 (6) 4 (12) None 3 (3) 41 (43) 39 (41) 42 (81) 23 (70) Average 1.23 2.23” 2.20” 2.65’ 2.4gb

a Statistically significant difference, p < 0.001. b Nonsignificant difference, p = 0.1. Average, see explanation Table 4.


TABLE 7. Range of movement loss

Range of movement loss, no. (%)

Preoper- atively 1 yr 2 yr 3 yr 4 Yr

Total 96 % 96 52 33

Severe 0 (0) 1 (1) 1 (1) 1 (2) 1 (3) Moderate 3 (3) 3 (3) 3 (3) 2 (4) 1 (3) Mild 25 (26) 19 (20) 19 (20) g (15) 6 (18) None 68 (71) 73 (76) 73 (76) 41 (79) 25 (76) Average 2.68 2.71” 2.71n 2.71” 2.67”

y No statistically significant difference. p = 0.38. Average, see explanation Table 4.

responding to pairs of overall scores from 0, 1 to 10, 11. The preoperative average score on the new scale was 2.22. It was 3.83, 3.69, 3.98, and 3.88 in the postoperative years 14, respectively. The overall score exhibits remarkable stability postoperatively, in contrast to the significant change at surgery. The postoperative results for pain and synovitis were significantly improved. There was no statistically significant difference in the range of motion, and the initial change in functional assessment was unsustained at the 2nd follow-up year.

Degree of cartilage damage A comparison of the results with the degree of

cartilage damage at the time of surgery indicates that the poor preoperative condition of the patient correlates with more extensive cartilaginous damage (Table 8). The postoperative results do suggest that with the greater degrees of cartilage damage, the results are not as good, but there is considerable variability. It would not be possible to predict the outcome based on the degree of cartilage damage at the time of surgery.

DISCUSSION

The Arthritis and Rheumatism Council and the British Orthopaedic Association (9) and the Arthri- tis Committee on the Evaluation of Synovectomy (1) found no significant benefits to synovectomy at

TABLE 8. Comparison of cartilage damage

Cartilage grade

0 1 2 3 4

No. (score) Preoperative 6 (7.5) 23 (7.3) 42 (5.8) 11 (4.9) 14 (4.6)

1 yr 6 (11) 23 (10.1) 42 (9.1) 11 (8.5) 14 (8.1)

2 yr 6 (10.2) 23 (9.8) 42 (8.8) 11 (8.7) 14 (7.7)

3 yr 3 (10.5) 13 (9.8) 24 (9.9) 7 (8.8) 5 (8) 4 yr 3 (10.5) 10 (10.2) 13 (8.9) 4 (10.3) 3 (10.7)


3-5 year follow-up observation (3). In view of this evidence, the risks of open surgical synovectomy would appear to be substantial. Both Laurin et al. (7) and Ishikawa et al. (2) report long-term results with good relief of synovitis and pain and improved function in rheumatoid knees following open synovectomy. The role of synovectomy in the man- agement of the rheumatoid knee remains controver- sial.

Arthroscopic techniques allow the removal of synovium from the knee with minimal morbidity (4,5). The technique outlined is safe in experienced hands, and there were no serious surgical compli- cations. The technique, therefore, potentially offers a benefit to the patient with minimal risk. This study has shown that arthroscopic synovectomy can suc- cessfully control synovitis and pain for up to 4 years. The range of movement is preserved although not increased. The function status, in this series, varies sufficiently as to allow no firm con- clusion. The results appear to be better in the cases with less initial cartilaginous damage.

These conclusions must be tempered by criticisms of this study. The study was not randomized or blinded, nor were there control groups. There was no attempt to control the patient’s medical treatment. Variables such as the rate of progression of the disease have not been accounted for. Spon- taneous remissions of the disease, however, are un- common in patients with a long duration of symptoms (10). On average, half of our patients have symptoms of less than 5 years’ duration.

In view of these criticisms, the role of arthroscopic synovectomy in the overall treatment of the rheumatoid patient is still not clearly defined. From this study there is no doubt that it can adequately improve important symptoms such as pain and synovitis, with maintenance of improvements over reasonable periods. Whether this will change the rate of progression of the disease or act simply as a

temporary palliative measure cannot be deter- mined. Further studies carried out in a prospective randomized and blinded fashion will be necessary. Sledge et al. reported 80% good results using a chemical synovectomy, and good initial results have also been reported with radiation synovectomy (11). Studies will also need to be done to determine the effectiveness of these forms of synovectomy in comparison with arthroscopic synovectomy and with medical therapy.

REFERENCES

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2.

The Arthritis Foundation Committee on Evaluation of Sy- novectomy. Multi-centre evaluation of synovectomy in the treatment of rheumatoid arthritis-report of the results at the end of three years. Arthritis Rheum 1977;20:765-71. lshikawa H, Ohno 0. Hirohita K. Long term results of synovectomy in rheumatoid patients. J Bone Join1 Surg 1986; 68A:198-205.

3. McEwen C. Multi-centre evaluation of synovectomy in the treatment of rheumatoid arthritis. Arthritis Rheum 1977;20: 765-7 I.

4.

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Klein W. Jensen K-U. Arthroscopic synovectomy of the knee joint: indication, techinique and follow-up results. Ar- throscopy 1988;4:63-71. Shibata T, Shiaoka K, Tarubo N. Comparison between arthroscopic and open synovectomy for the knee in rheumatoid arthritis. Arch Orfhop Truuma Surg 1986;105:257-62. Outerbridge RE. The etiology of chondromalacia patella. J Bone Joint Surg 1976;43B:752-7. Laurin CA, Desmarchais J, Dazino L, Gariepy R, Drome A. Long term results of synovectomy of the knee in rheumatoid patients. J Bone Joint Surg 1974;56A:521-31. Bishop YMM, Feinberg SE, Holland PW. Discrete multi- variate analysis: theory and practice. Cambridge. Massachu- setts: MIT Press, 1975. The Arthritis and Rheumatism Council and British Ortho- paedic Association. Controlled trial of synovectomy of the knee and metacarpalphalangeal joints in rheumatoid arthritis. Ann Rheum Dis 1976;35:43742. Harris ED. Rheumatoid arthritis-the clinical spectrum. In: Kelly WN, Harris ED, Ruddy S, Sledge CB, eds. Textbook of rheumatology. 2nd ed. Philadelphia: WB Saunders, 1985: 915-50. Sledge CB, Zuckerman JD, Shortkroff S, et al. Synovec- tomy of the rheumatoid knee using intra-articular infection of dyprosium 165, ferric hydroxide macroaggregates. J Bone Joint Surg 1987;69A:97&5.

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arthroscopic synovectomy of the knee for rheumatoid arthritis

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