IN DEFENCE OF THE MENISCUS

Transcription

1 IN DEFENCE OF THE MENISCUS A PROSPECTIVE STUDY OF 200 MENISCECTOMY PATIENTS J. NOBLE, K. ERAT From The Princess Margaret Rose Orthopaedic Hospital, Edinburgh 0f250 patients scheduled f meniscectomy 50 had symptoms which subsided and operation could be deferred; ofthe remaining 200 only 73 per cent were found to have a significant tear. It is shown that the risks of removing a nmal far exceed those of leaving a tear in the posteri third. Statistical analysis of clinical features revealed no reliable diagnostic pattern. The advent of arthrography and arthroscopy have highlighted the difficulties of diagnosing meniscal lesions. Much of the success with these time-consuming techniques appears to have been in Nth America. At the moment it is likely that only a minity of British surgeons will acquire that expertise with arthroscopy described by Jackson and Dandy (1976). Indeed it is probable, in the current economic climate, that many will not even be able to acquire an arthroscope (Lancet 1976). Not all practitioners of arthrography (DeHaven and Collins ; Axer et al ) rept the success rate of over 90 per cent described by those Nth American auths who have become particularly expert with the technique (Nicholas, Freiberger and Killan 1970; McBeath and Wirka 1972; Kaye and Freiberger 1975). The potential weakness of both techniques is in demonstrating the posteri third of the and it is here, where are most common, that false positive results and false negatives occur. Although the best compromise may be to depend upon a combination of clinical diagnosis, arthrography and arthroscopy, the surgeon first has to exercise clinical judgement in selecting patients f either investigation. This can only be based upon clinical features, which, despite being familiar, have previously not been prospectively and statistically assessed in terms of their diagnostic reliability. Despite arthrography arthroscopy the situation will arise wherein the knee is opened and no tear is obvious. It is then that Watson-Jones (1956) teaching that the cartilage should be removed f fear of leaving a posteri tear, invisible from the front, becomes a real threat to the. One has to balance the risks of leaving such a tear against those of excising a nmal. No surgeon can escape this dilemma. MATERIAL AND METHODS Two hundred and fifty consecutive patients scheduled f meniscectomy, in a few cases, f explaty arthrotomy f a possible meniscal tear, were studied by one observer. All symptoms and signs befe operation were recded on a detailed profma, as well as the radiographic features and all operative findings. The clinical features were then crelated with the meniscal and intra-articular abnmalities. The diagnostic are shown in Table I. The vertical comprised 30 per cent of the findings at arthrotomy, while hizontal lesions were encountered in 38.5 per cent, some of which were in a less well recognised group in which the bucket-handle tear was based upon a hizontal lesion. Of the two diagnostic in which the was found to be Table I. Diagnosis I. Diagnostic Per cent Bucket-handle 15.0 Complete peripheral separation Posteri peripheral separation Posteri hn (fish-tail) Hizontal lesion Posteri Associated Complete third parrot-beak 3. Hizontal lesion and bucket-handle tear Nmal -removed Nmal -left in place Cystic lesion-alone Discoid lesion-alone J J. Noblc, MB ChB FRCSEd, Seni Lecturer in Orthopaedic Surgery, University of Manchester, Hope Hospital, Eccles Old Road, Salfd M6 8HD, England. K. Erat. BA, Research Associate (Computer Science), Department of Surgery. Peter Bent Brigham Hospital. Boston, Massachusetts 02 I I 5, U.S.A. Requests f reprints should be sent to Mr J. Noble. VOL. 62-B, No. I. FEBRUARY 980

2 J. NOBLE, K. ERAT nmal only Group 4, in which the was removed, was used f statistical comparisons as nmality had only then been established beyond doubt; a comparison was made, however, f all clinical features between these two. The eight cystic menisci and the one discoid which did not have an associated tear were not included in the ensuing crelations. A further eight meniscal cysts were encountered, but these were associated with meniscal and were classified as such. The symptoms, signs, age distribution, side, sex, type of onset and duration of complaints were crelated between Groups 1, 2 and 4. F simplicity only the me imptant clinical features are considered here. Subsequently the first three diagnostic were combined into one tear positive group and Groups 4 and 5 into a tear negative group. Computer programmes were written in which the chi-square test was used on any combination of between two and 1 0 of the following clinical features: symptoms-pain as the predominant complaint, pain at night, locking, instability and effusion; signswasting effusion, tenderness hyperaesthesia over the joint line, a block to extension and a positive squatting duck-waddle test. By these means the incidence of these features in the tear positive and tear negative could be compared. Further comparisons were made f each patient, by giving a point f each positive feature and comparing the mean points sce between the tear negative group and the tear positive group. Two hundred and fifty patients were iginally called in f meniscectomy, but 50 never underwent operation. The reasons were as follows: 25 spontaneously improved while awaiting operation and asked that their names be removed from the waiting list and a similar situation was discovered with a further 10 patients on admission to the hospital, so that they were dismissed without operation ; another 10 patients defaulted and five were treated conservatively. These observations are only as statistically reliable as the clinician who iginally made them. F each patient the clinical features recded by that observer the day befe operation were compared with those recded the same day by the admitting surgeon. Where any significant difference existed between these observations the clinical features were reconsidered by both parties. CLINICAL FINDINGS The majity of patients (63.2 per cent) had an acute onset of symptoms, associated with an injury, whereas 24.9 per cent had an insidious onset. Between these two extremes per cent had an acute onset unassociated with any significant injury. Fty-three per cent of the patients had had symptoms f me than a year. Of the 200 patients who underwent operation, 146 had a significant meniscal tear, giving a diagnostic accuracy rate of 73 per cent; when considered in relation to the iginal 250 patients scheduled f operation, this represented a diagnostic accuracy of only 58.4 per cent. The features identified at arthrotomy, in the 54 patients in whom the menisci appeared to be nmal, are enumerated in Table II; in 15 of them no abnmality was identified. There were 3.2 meniscectomies where meniscal were found f every one with a nmal cartilage among the male patients, whereas f the females the ratio was 1. 1 to 1. In 25 of the 54 patients where no abnmality was found at arthrotomy a nmal was removed, usually in the spirit of Watson-Jones teaching and this represents 14.6 per cent of all the meniscectomies in this series. Transverse of the anteri hn mid ption, unassociated with a Table II. Intra-articular findings in 54 knees in which the appeared to be nmal Findings Number knees Chondromalacia patellae patellofemal osteoarthritis 15 Synovitis synovial hypertrophy 9 Lesion of the fat pad 8 Ligamentous lesion 4 Loose body osteochondritis dissecans 4 Tibiofemal osteoarthritis 3 Synovial chondromatosis 1 Ganglion 1 No abnmality 15 hizontal tear, were not regarded as significant abnmalities, as they may be caused by linear traction upon a curved structure during mobilisation of the ; neither were menisci with a frayed edge, discolation, softening fibrillation with no frank tear. There were no significant differences in any respect between the arthrotomies with negative findings where the had been removed and those in which it had been left. Table Ill. Age and sex of patients and side and onset of lesions expressed as percentage distribution in three diagnostic Age (years) Over6O Malepatients Hizontal Nmal menlscus Medial Onset Less than 1 month 1 to 12 months Me than 1 year Acute and traumatic Acute Insidious of THE JOURNAL OF BONE AND JOINT SURGERY

3 IN DEFENCE OF THE MENISCUS 9 Whereas the patients with vertical were younger and had shter histies it is emphasised that a third of the h#{224}rizontal lesions were encountered in people under the age of 30 (Table III). The onset was acute and traumatic in 54.4 per cent of the patients with a hizontal lesion, and insidious in 38.6 per cent. In contrast, only 19 per cent of the group with vertical had an onset not involving trauma beyond a trivial domestic incident (Table III). Pain (including pain at night) was the predominant complaint in less than half of the group with vertical and was not invariable at the onset of the histy in any of the three compared (Table IV). Although pain at night was twice as common among patients with hizontal as in those with vertical, it was just as frequent with a nmal. Locking was commonest with the vertical and instability predominated with the Table IV. Percentage incidence of symptoms in three diagnostic associations were between a block to ( loss of) extension and any combination of wasting, tenderness over the joint line ligamentous laxity. With female patients there was an 80 per cent, better, chance of the arthrotomy findings being negative if the pain was general ill-localised and not associated with effusion a block to extension. Sixty-one per cent of the male patients with negative findings at explation had ill-localised pain. Table V. Percentage incidence of physical signs in three diagnostic Hizontal Nmal Effusion Wasting of the quadriceps Tenderness over the affected joint line Tenderness over the ipsilateral ligament Hizontal Nmal Swelling of the joint line Ligamentous lesion Initial complaint was pain Pain now Pain at affected joint line Night pain Night pain which disturbs sleep Night pain caused by knees touching Locking Instability Effusion Stiffness Symptoms on walking hizontal lesion. However, 52 per cent of the patients with hizontal complained oflocking and 62.5 per cent of those with nmal menisci complained of instability. The incidence of tenderness and limitations of movement are shown in Table V. The average number of clinical abnmalities in the tear positive group was 13.3, whereas f the tear negative group it was This difference was not statistically significant, and neither were the other results from the other scing methods applied. The only symptom combinations with a probability better than P<0. 1 were continuing pain, effusion and locking; locking and instability; and locking and effusion. Regarding signs, the only significant (P<0.1) Lacks full extension Lacks full flexion Positive McMurray sign Positive squat duck waddle Hyperaesthesia over the joint line In 20 patients (1 0 per cent) both medial and lateral compartments were opened, although in five of them the second arthrotomy was delayed f between one and six months. In eight patients both menisci were nmal and in four both were pathological, whereas in the remaining eight the second and previously unsuspected compartment was the seat of a silent, significant tear. DISCUSSION Reliability of clinical features. Despite a wealth of references to the signs and symptoms exhibited by patients with tn menisci this is the first study in which their reliability has been studied prospectively. In 20 per cent of the patients with a diagnosis of tn the symptoms settled, indicating their unreliable transience. To date we know that only two of these 50 patients have subsequently come to arthrotomy, one having a degenerate tear, the other having negative findings at explation. As no specific sign symptom consistently means a specific lesion it is best, in all but the most acute and VOL. 62-B, No. I. FEBRUARY 1980

4 10 J. NOBLE, K. ERAT obvious cases, to examine the patient two three times over several weeks befe any firm surgical decision is made. The similarity of symptoms in those with a hizontal tear and those with a nmal siggests a common igin which could be an underlying synovitis. Me imptant than any distinction between different types of tear is the absence of any reliable clinical pattern differentiating between the patients with a tn and those without. The decision to excise a should therefe not be based upon clinical features. Clinical significance of meniscal pathology. That 54 of the 200 patients (27 per cent) who underwent arthrotomy did not have a tn might suggest a lack of diagnostic acumen, especially as a number of series make little no mention of finding a nmal (Wynne-Parry, Nichols and Lewis 1958; Helfet 1959; Appel 1970). However, similar sparse mention is made of the hizontal lesion, the commonest of all meniscal (Smillie 1970). Lipscomb and Henderson (1947) found that in 21.7 per cent of the series at the Mayo Clinic no tear was found at operation; McBeath and Wirka (1972) had similar findings. Me recently the arthroscopic data of Dandy and Jackson (1975) and of DeHaven and Collins (1 975) have shown the diagnostic difficulties and the need f expert arthroscopy. It may be that the number of negative findings in our meniscectomy series has been increased by not regarding discoloured menisci with frayed edges transverse of the anteri hn as significant. The imptant functions of the have been demonstrated (Walker and Erkman ; Krause et a!. 1976), and the long-term sequelae of meniscectomy have been recognised f some time (Fairbank 1948; Gear 1967; Jackson 1968; Tapper and Hoover 1969). The classical teaching of Watson-Jones therefe needs to be reviewed. Whereas we would not question the need f early removal of an acute, displaced, buckethandle tear, the risks of leaving other significant meniscal abnmalities should be reconsidered. Undisplaced peripheral separations can be readily demonstrated by increased mobility of the upon traction with a blunt hook at arthrotomy. A small posteri peripheral tear which cannot be demonstrated in this manner is likely to be unimptant. The majity of other posteri will be hizontal and upon applying a little traction anterily and viewing from the level of the tibial plateau it is usually easy to see their ragged bder and mouth. As cystic and discoid cartilages present no diagnostic problems, concern remains only regarding posteri-third vertical, the so-called fish-tail lesions which represent only three per cent of this series. Therefe, in this study, the risks of leaving such a tear in the posteri third were only 1 in 33, whereas those of finding no meniscal tear and therefe of removing a nmal were potentially one in four. Although the sequelae of removal are well known, those of leaving behind a tear in the posteri third of the remain unknown. Noble and Hamblen (1975) have demonstrated the possibility of severe osteoarthritis coexisting with untn menisci, and vice versa. If hizontal of the posteri third are potentially detrimental to the articular cartilage, then on the basis of their findings there must be at least three million people in Britain requiring a meniscectomy. Johnson et al. ( 1 974) and Gear ( 1 967) have suggested that the longer the period between the first complaint and the operation the less favourable the result; however, Johnson s follow-up rate was 22.5 per cent and Gear s 27 per cent, rendering such conclusions suspect. Both Jackson ( 1 968), with a larger number of patients and a 90 per cent follow-up, and Appel (1 970) have shown that long-term results of meniscectomy are not adversely affected by the length of time from diagnosis to meniscectomy. If, at arthrotomy, no abnmality exists in the to which the clinical features pointed, then the other cartilage should be examined. Among 200 arthrotomies there were 1 2 cases where either the other both were tn, although unftunately this was not always recognised at the same sitting. However, if one is faced with an open joint and two apparently nmal menisci then nothing is lost by closing the joint and awaiting further developments. This study was iginally stimulated by Professs J. I. P. James and D. L. Hamblen to wom much gratitude is due, as it is to Mr John Chalmers f his help in the preparation of this paper. Grateful thanks are due to all surgeons and registrars at the Princess Margaret Rose Orthopaedic Hospital who gave full access to all their clinical material and much friendly help. We are also most grateful to the Department of Surgery at the Peter Bent Brigham Hospital in Boston, Massachusetts, f use of their computer facilities. REFERENCES Appel H. Late results after meniscectomy in the knee joint. Acta Orthop Scand 1970;Suppl.133. Axer A, Segal D, Hendel D, et al. Arthrography and arthroscopy in the diagnosis of internal derangement of the knee. Harefuah 1 976;91:61-3 [in Hebrewj. Dandy Di, Jackson RW. The impact of arthroscopy on the management of disders of the knee. J Bone Joint Surg [Br] 1975;57-B: DeHavenKE, Collins HR. Diagnosis of internal derangement of the knee. J Bone Joint Surg [Am] 1975;57-A: Fairbank TJ. Knee joint changes after meniscectomy. J Bone Joint Surg [Br] 1948;30-B: Gear MWL. The late results of meniscectomy. Br J Surg 1967;54: Helfet A. Mechanism of derangement of the medial semilunar cartilage and their management. J Bone Joint Surg [Br] 1959;41-B: Jackson JP. Degenerative changes in the knee after meniscectomy. Br Med J I 968;2: THE JOURNAL OF BONE ANI) JOINT SURGERY

5 . IN DEFENCE OF THE MENISCUS 1 1 Jackson RW, Dandy Di. Arthroscopy ofthe knee. New Yk: Grune and Stratton, Johnson Ri, Kettlekamp DB, Clarke W, Leaverton P. Facts affecting late results after meniscectomy. J Bone Joint Surg [Am] 1 974;56-A: Kaye Ji, Frelberger RH. Arthrography of the knee. Clin Orthop 1975;107: Krause WR, Pope MH, Johnson Ri, Wilder D. Mechanical changes in the knee after meniscectomy. J Bone Joint Surg [Am] 1 976;58-A: Lancet. Editial: unnecessary meniscectomy. Lancet ;1: Llpscomb PR, Henderson MS. Internal derangements of the knee. JAMA 1947;135: McBeath AA, Wirka HW. Positive-contrast arthrography of the knee. Clin Orthop 1972;S8:70-5. Nicholas JA, Frelberger RH, Killan PJ. Double-contrast arthrography of the knee. J Bone Joint Surg [Am] 1970;52-A: Noble J, Hamblen DL. The pathology of the degenerate lesion. J Bone Joint Surg [BrJ 1975;57-B: Smillie IS. Injuries ofthe knee joint. 4th ed. Edinburgh: Churchill Livingstone, 1970:50. Tapper EM, Hoover NW. Late results after meniscectomy. J Bone Joint Surg [Am] 1969;51-A: Walker PS, Erkman Mi. The role of the menisci in fce transmission across the knee. Clin Orthop 1975;109: Watson-Jones Sir R. Fractures and joint injuries. Edinburgh: E & S Livingstone Ltd. 1956;ll:769. Wynne-Parry CB, Nichols PJR, Lewis NR. Meniscectomy: a review of 1723 cases. Ann Phys Med 1958;4: VOL.. 62-B, No. 1. FEBRUARY 1980