INTEROSSEOUS MUSCLE BIOPSY DURING HAND SURGERY FOR RHEUMATOID ARTHRITIS By M. RILEY, M.B., M.R.C.P. and STEWART H. HARRISON, F.R.C.S., L.D.S R.C.S. (Ed.) M.R.C. Rheumatism Research Unit, Canadian Red Cross Memorial Hospital, Taplow, Maidenhead, Berks. IN I949 Kestler described histological changes occurring in all the intrinsic muscles of the hand in i I cases of rheumatoid arthritis. He stated," the characteristic deformity of the rheumatoid hand is the result of simultaneous factors of which the primary and dominating feature is the direct involvement of the intrinsic muscle apparatus proper by the rheumatism process. The wonderful precision balance of the intrinsic apparatus is disturbed through thus establishing the first link in a chain of pathological sequences " Since this there have been no further papers on the histology of the intrinsic muscles, although in 1955 Bunnell stated that microscopically the muscles, tendons and ligaments show minute foci of inflammation and later fibrotic contracture ; and in 1965 Flatt stated that rheumatoid involvement produces spasm and fibrosis of the intrinsics, and atrophy is so common and so characteristic that it represents one of the diagnostic criteria of the presence of rheumatoid arthritis. The present study was undertaken to attempt to evaluate the degree of involvement of the dorsal interossei in rheumatoid arthritis and to find out if these changes were in any way related to the severity of the general disease or to any specific hand deformity. Material.--Twenty-eight patients submitted for hand surgery have had biopsies usually of the first dorsal interosseous. A total of 3I specimens were obtained, three patients having two surgical procedures at different times. The specimens were fixed in buffered formalin, mounted in paraffin blocks, then sectioned at 5 microns and stained with hmmatoxylin and eosin. Method.--On light microscopy, the features looked for were evidence of so-called " nodular polymyositis ", wasting of the muscle, and any evidence of fibrosis or increase in connective tissue within the muscle. " Nodular polymyositis ", a chronic inflammatory change, was considered present when there were circumscribed collections of at least 50 cells, mainly lymphocytes and plasma cells, either perivascular (Fig. I) or located in the peri-endo or epimysium (Fig. 2). was diagnosed by a subjective increase in the proportion of sarcolemmal nuclei, shrinkage of muscle fibres and any vacuolisation. Results.--Out of a total of 31 biopsies (Table I), 14 were normal. In nine there was evidence of wasting with alteration in fibre size and marked increase in sarcolemmal nuclei but with no cellular infiltration. Eight showed focal collections of chronic inflammatory cells, predominantly lymphocytes, in the peri- or epimysium and perivascular collections of lymphocytes together with signs of wasting. There was no evidence of increased amounts of collagen or fibrosis in any of the specimens. Analysing the three groups in relation to the duration of rheumatoid arthritis to surgery (Table II), those with wasting had a longer course than the other two groups ; there was also a higher percentage of sero-positive cases in this group. Patients treated with corticosteroids had a higher incidence of inflammatory change, though the differences were not statistically significant. 342
FIG. I Longitudinal section of muscle from Case I, Table III~ showing perivascular collection of lymphocytcs and clumping of sarcolemnal nuclei. (H. & E. 2Io.) FIG. 2 Cross-section of muscle from patient undergoing metacarpophalangeal arthroplasty~ showing circumscribed collection of chronic inflammatory cells with some focal atrophy of muscle. (H. & E. 2IO.)
TABLE I Interosseous Muscle Biopsies in Rheumatoid Arthritis. Number Percentage. 14 45 ). Inflammatory change 9 8 29 j 55 26 I Total 31 IOO TABLE II Histological Changes in relation to Duration of Disease, DAT and Corficosteroid Therapy No. Duration to surgery Sero-positive Steroid therapy. Inflammatory 14 3-20 yr. Mean 9 8 4-20 yr. Mean I2 6-18 yr. Mean IO Total 31 3-2o yr. Mean IO 19 II TABLE III Comparison of Findings in Patients with Bilateral Biopsies Date of Year of Year of Name birth onset operation Hand deformity Histology of muscle i. D.R. (F) I9o9 I95I (I) I963 (2) I964 L. Swan's neck R. Swan's neck Inflammatory change 2. D. C. (F) 194 I96I (1) 1965 (2) 1966 L. Ulnar deviation L>R R. Ulnar deviation 3. J. W. (F) 1943 1956 (1) I965 (2) I966 R. Ulnar deviation+ MCP subluxation L. Ulnar deviation TABLE IV Histological Findings compared with Hand Deformity Histology Hand deformity Total Inflammatory change No deformity Ulnar deviation. Ulnar deviation with "subluxation of MCP joints... Swan's neck deformity of fingers Swan's neck deformity and subluxation of MCP joints Total 31 14 9 8
INTEROSSEOUS MUSCLE BIOVSlES IN RHEUMATOID ARTHRITIS 345 Three patients had muscle biopsies on two different occasions (Table III). In Case I both operations were for swan's neck deformity and the relevant interosseous muscle was normal in the left hand but showed inflammatory change in the right. In Cases 2 and 3 the muscle biopsies from the more severely affected hands showed wasting. Comparison of the histological changes present with the anatomical deformity of the hand (Table IV) demonstrates that muscle wasting is present in a higher percentage of the severely deformed hands and in those with ulnar deviation, whereas inflammatory changes may occur with any or no deformity and are certainly not a characteristic feature of any particular anatomical derangement. DISCUSSION In 1946 Steiner et al. described nodular polymyositis with increased collagen and secondary atrophy in nine cases of rheumatoid arthritis which was not present in 196 controls. Since then there have been many other series giving an incidence of nodular polymyositis varying from 25 per cent. (Ogryzlo, i948 ; Lenoch et al., 1962) through 56 per cent. (Sokoloff et al., I95O), 60 per cent. (Yates, 1962) to 82 per cent. (De Forest et al., 1947). They considered that the atrophy was in association with the inflammatory change and did not include wasting as a separate entity. That these changes are non-specific was demonstrated by Sokoloff et al. (195o) who, reviewing 202 biopsies of 57 patients with rheumatoid arthritis and a control group including patients with ankylosing spondylitis, rheumatic fever, rheumatic heart disease, degenerative joint disease and healthy adults, found lesions in 25 per cent. of the controls varying from 4o per cent. in ankylosing spondylitis to 3 per cent. in healthy adults. Involvement of dorsal interossei found in this series shows a similar incidence of muscular changes elsewhere and it is doubtful flit is any more specific in the hand than in other muscles of the body. Despite the statements of Kessler (1949) and Flatt (1965), in our study atrophic changes were more common the longer the duration of the disease and in sero-positive cases. Inflammatory changes were seen slightly more often in those cases maintained on corticosteroid therapy. It could, however, be argued that this represented the more severe disease process. The only association between muscle involvement and hand deformity was a higher incidence of wasting with ulnar deviation alone and ulnar deviation with metacarpal phalangeal subluxation ; that is, the most severely damaged hands. It is, therefore, more likely that these changes are secondary to the gross deformity and limitation rather than primary mtiological factors. SUMMARY Considering the meagre histological evidence, we feel that there has been undue emphasis placed upon direct involvement of the hand muscles in rheumatoid arthritis and its role in the production of specific hand deformities. We are grateful to Dr L. E. Glyn for advice in the histological assessment, and to Professor E. G. L. Bywaters and Dr B. M. Ansell for their help, encouragement and criticism in the preparation of this article.
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