Diagnostic and therapeutic value of early synovectomy of the knee joint -(An analysis of 60 cases)DN Hormusjee, MN Shahane
Department 0f Orthopaedics. K.E.M. Hospital and Seth G.S. Medical College. Parel, Bombay-400 012, India
Correspondence Address: Source of Support: None, Conflict of Interest: None PMID: 529169
Source of Support: None, Conflict of Interest: None
A study of sixty well selected cases of synovitis of the knee joint, treated by timely adequate synovectomy, followed up over a period of four years is presented. We have stressed the importance of therapeutic and diagnostic value of synovectomy. The results are found encouraging and the procedure useful in preventing damage to the articular structures of the knee joint. The best results are obtained in non-specific, traumatic and very early cases of rheumatoid arthritis while infective arthritis benefits to fair extent.
Synovitis of the knee joint is a challenging problem to tackle for an orthopaedic surgeon. Averagely one sees 4-5 cases in a busy outdoor of a general hospital where patients present with vague corn plaints of pain and swelling of the knee joint. In most of these cases the swelling has progressed over a long period with not much of pain to disable the patient sufficiently and make him seek earl orthopaedic advice.
Usually the movements in the joins concerned are functionally accepted by the patient but the patient least realises that synovial swelling is a warning signal of a forthcoming disaster.
Osteoarthritis, rheumatoid arthritis, low grade pyogenic infection, traumatic affection or non-specific synovitis, though not impossible, are difficult to differentiate only on clinical examination. There is a limit to treating these cases on conservative lines especially when one sees that in spite of the empirical treatment the patient's symptoms are either not relieved or they are frankly progressive.
Synovectomy of the knee joint done in good time is a simple procedure which combined with proper use of drugs and physiotherapy gives good results. It confirms the diagnosis and salvages the knee as the menisci, the articular cartilage and ligaments are saved from any further damage which the synovium would have caused if surgery was deferred. This is a study of sixty well selected cases of synovitis of the knee joint treated by early synovectomy.
Sixty cases of synovitis of the knee joint treated by early synovectomy at the K.E.M. Hospital, Bombay, between the period of 1972 and 1976 are analysed here. Of the 60 cases, 17 had frank synovial effusion and thickening with range of motion less than 90%. Twenty-two of them had minimal synovial thickening but recurrent effusion and as a result grossly wasted quadriceps. Remaining 21 cases belonged to a group which presented with vague pains and very occasional effusion but had definite synovial thickening palpable. Majority of these had received conservative line of treatment either from a general practitioner or by a surgeon.
Age and Sex
Most of the cases belonged to the younger age group, the youngest patient was 7 years old and the oldest was 52 years old. Out of 60 patients, 13 were below 20 years of age, 29 were in the 20-30 year age group, 14 were in the 31-40 year age group and only 4 were above 40 years of age. There were 39 males and 21 females in this series.
Side of affection and duration of Symptoms
There were 27 right-sided and 33 left-sided affections. Most cases presented in the initial six months of their complaints. Some had taken the proper conservative line of treatment during that period, in terms of anti-inflammatory drugs, local heat and quadriceps strengthening exercises but with very little benefit. All these cases were again subjected to conservative line of treatment and when found not responding were subjected to subtotal surgical excision of synovium.
Criteria used for selection of the case for surgery
Synovectomy is an acceptable rationale and standard procedure for synovial affections of the knee-joint but one definitely waits till a time when there arises a definite indication for surgical intervention. We have used the criteria as detailed in `Discussion' before subjecting the cases for surgery.
In addition to standard criteria for undertaking synovectomy, we have used following as special criteria:
1. Cases with synovial hypertrophy acting as a block or obstacle to the functional recovery of the knee by overstretching the ligaments capsule and increasing the intra-articular tension.
2. Cases where sufficient conservative trial has failed to give result.
3. To establish a definite histopathological diagnosis.
4. Where limited synovial biopsy has proved non-conclusive or the knee had steadily deteriorated in spite of conservative treatment after a conclusive biopsy done earlier.
Patients were subjected to the routine investigations like blood count, ESR, X-rays of the knee and chest. In cases with evidence of multiple joint involvement R.A. test, C. reactive proteins and A.S.O. titre were evaluated. The range of motion was carefully recorded at the knee joint. Any laxity of ligaments was noted and under aseptic precaution in cases where synovial effusion existed aspiration of the knee joint was done and fluid was subjected to smear culture and antibiotic sensitivity. In cases which gave an impression of rheumatoid affection, R.A. test of the aspirate was also performed.  These tests cliniched the diagnosis in 17 out of 60 cases, while in the remaining 43 cases these tests were non-conclusive.
All the cases were operated under general anaesthesia using a pneumatic tourniquet. The standard medial parapatellar incision was used.' The joint was exposed from proximal most part of the supra-patellar pouch to the tibial condylar margin. The capsule and the supra-patellar pouch were dissected free from the quadriceps expansion from above downwards and the supra-patellar pouch en masse was excised. The synovium and the pannus of the synovium at the articular margin and in the intercondylar notch were excised by sharp dissection. The menisci, ligaments, articular cartilage, and the metaphyseal area of the lower end of the femur were inspected and if found damaged were dealt with adequately. The joint was given a thorough wash with antibiotic solution and the wound was closed in layers. Knee was immobilised in full extension but only a compression bandage was used. No plaster immobilization was used in any of the cases.
Patients were given routine broad spectrum antibiotics. The knee was supported by a small soft pillow kept under it and patients were instructed to follow a regime of static quadriceps exercises within a couple of days. In cases where gross pathology was obvious definitive chemotherapy was started without waiting for the histopathology report. On the 10th post-operative day or even earlier in certain cases gentle knee flexion exercises were started. All these patients were always kept on the bed and were not allowed to occupy the ground mattresses. This helped a lot in mobilizing the knee as the patient himself could do knee flexion and quadriceps exercises sitting at the edge of the bed. Sutures were removed on the 10th day and depending on the pathology patients were allowed weight hearing subsequently.
Patients were regularly followed up in the out-patient department, for a period between 1 and 4 years. Three cases were followed for less than 1 year, 5 cases from 1 to 2 years, 20 cases from 2 to 3 years and 32 cases from 3 to 4 years. All these cases were assessed from the point of view of residual pain, their gait, mobility at the knee joint, laxity of ligament if any, synovial swelling if persisting, their quadriceps power and quadriceps girth. Accordingly, we graded the results into four groups by the following criteria:
Good: No pain and limp, full mobility at the knee joint without laxity of ligaments or synovial swelling. Quadriceps power-grade V with normal girth, as compared to the opposite limb and no quadriceps lag.
Fair: Full mobility without pain, minimal limp, slight post-operative swelling around the knee which later subsided. Good quadriceps power. No lag.
Poor: Persisting pain and limp, subnormal mobility at the knee joint, laxity of ligament and swelling around the knee.
Quadriceps power-Grade IV with persisting wasting and stiffness.
The average time taken to achieve a painless mobile knee with good quadriceps power and stability was anything between 3-8 weeks depending on the pathology. There were 36 (60%) good 18 (30%) fair and 6 (10%) poor results. All the 6 cases which resulted in deterioration of the knee joint were of infective pathology, either septic or tubercle with gross damage to the joint. Histopathology revealed that 28 cases belonged to rheumatoid affection (See [Figure 1],[Figure 2] and [Figure 3] on page 170A), 10 cases proved to be of non-specific synovitis, 8 cases where histopathology did not reveal any conclusive finding were the cases which had early osteoarthritic changes, 12 showed Koch's lesion, and 2 were septic in nature.
We encountered the complications like initial stiffness (5 cases) of the knee which responded well to timely guarded manipulation. There were 7 cases which had residual discharging sinuses but they subsided with subsequent chemotherapy. Six cases showed no improvement but deteriorated after surgery and had considerable stiffness with pain. All these six cases were of infective synovitis.
The operation of early synovectomy is a salvage procedure which saves the knee joint from further damage to the ligaments menisci and articular surfaces. This operation has resulted in relief of pain in a high percentage of cases. The elimination of pain has permitted redevelopment of muscle power and consequent improvement of function of the joint as a whole. This series gives enough evidence with a long follow up that we have undertaken that eradication of aggressive synovial membrane which is vascular pannus in rheumatoid while toxic destructive in pyogenic and slow but steadily destructive in tubercle cases when excised in good time prevents abnormal contact of the membrane with the articular cartilage and prevents it from invading subchondral bone thus retarding destruction of the joint. Smillie  quotes a case in his monogram on "Diseases of the knee joint" that a case of 12 years' follow tip where two knees of the same person were simultaneously involved by rheumatoid pathology and one was synovectorni5ed and the other left alone due to certain unavoidable circumstances, showed that the synovectomised knee was near normal at the end of 12 years while the other knee was the subject of gross osteoarthritis with painful limited motion. 
In this series the criteria on which early synovectomy has been undertaken were pain, persistent swelling, early involvement of the second knee in presence of advanced destruction of the first, clinical evidence of synovitis with minimal radiological changes, no limitation of flexion other than as a result of synovial swelling and mild pain and no serious involvement of other weight bearing joints ,
Possibility of loss of flexion in a synovectomised knee exists. If synovectomy is a rational procedure in terms of removal of pathological tissue, it is irrational in terms of motion in that it involves excision of opposing gliding surfaces of supra-patellar pouch and else- where. Thus the earlier the synovectomy is done as a prophylactic measure the less may be the subjective benefit for the patient but the amount it pays in the long run can only be analysed in a series like this.
We are able to conclude from the series that a simple procedure like synovectomy in a well selected cases performed in good time salvages the knee. The procedure is not only of therapeutic value but gives us a definite diagnosis on which one frames the further line of treatment. Early mobilization and good quadriceps regime have proved of immense value in the post-operative recovery of the knee, and therefore, one should not be hesistant in undertaking this simple procedure.
Thanks are due to the Dean, K.E.M. Hospital, Bombay, for permitting us to report the hospital data.
[Figure 1], [Figure 2], [Figure 3]