Postgrad Med J: first published as 10.1136/pgmj.44.517.848 on 1 November 1968. Downloaded from Postgrad. med. J. (November 1968) 44, 848-850.

Hard and soft osteo-arthritis

C. P. BROAD M. B., F.R.C.S. The Rowley Bristow Orthopaedic Hospital, Pyrford, Surrey

Summary remarkably constant and has a rational basis in This short paper attempts to show how the pathology. X-ray appearance influences the choice and Secondary osteo-arthritis may follow mechan- success of operative procedures performed on the ical anomalies (e.g. fractures into the joint, devel- hip and knee joints for osteo-arthritis. If the opmental disorders, mal-alignment, etc.) in which bones look 'soft' the only methods likely to suc- case the texture of the bone is relatively normal ceed are those in which total replacement and it looks 'hard' on X-ray. But when the degen- coupled with the use of cement ensure firm erative changes are secondary to rheumatoid anchorage and wide distribution of stress. When arthritis the bone looks 'soft', as it also does in bones look 'hard' simpler methods are usually osteoporotic disorders. satisfactory. When 'soft' bone osteoarthritis of the hip was treated by prosthetic replacement of the femoral IN THE treatment of osteo-arthritis it is usually head the result was often unsatisfactory. Pain wasProtected by copyright. easy to decide whether or not operative treatment not relieved or it subsequently recurred; and later is indicated: but frequently it is difficult to X-ray films showed the prosthesis migrating down choose which operation is best suited to the the femoral shaft, or burrowing into the pelvis, or individual patient. The three basic procedures are both (Fig. 2). Even osteotomy rarely succeeded, arthrodesis, osteotomy and arthroplasty. Arthro- presumably because any biological regeneration desis is usually reserved for those patients in was more than offset by the continuing collapse whom one joint only is involved, the 'compensat- of the soft bone. But even with 'soft' bone a ing' joints are reasonably supple and the patient total hip-replacement using McKee's technique fairly young. Osteotomy is most likely to succeed was nearly always successful. The essential where the joint has a reasonable range of move- feature is probably the wide distribution of stress ment and the disease is not so advanced that afforded by the use of the cement which anchors bone collapse precludes the probability of joint the metal components. regeneration. Arthroplasty is the only feasible With 'hard' bone osteo-arthritis at the hip,

procedure for all other patients and nowadays a procedures less elaborate than total replacement http://pmj.bmj.com/ variety of techniques is available. were usually adequate. Osteotomy was successful The present hypothesis is not concerned with (providing the joint preoperatively had at least those cases selected for arthrodesis. It attempts 700 of flexion and little bone collapse had to rationalize the choice between osteotomy and occurred), and cup arthroplasty or simple re- arthroplasty as well as indicating which technique placement of the femoral head with a Moore's of arthroplasty should be used. or Thomson's prosthesis were also satisfactory. The hip and knee joints were selected for study, Similarly Ring's total hip replacement although these being the joints at which the problem was not employing cement was successful, presum- on September 30, 2021 by guest. most often encountered. When patients were ex- ably because the long screw carrying the acetabu- amined at least 2 years after operation it was lar component obtained an excellent grip on the relatively easy to decide which were successful 'hard' bone of the ilium. or which were failures. Next the X-ray films At the knee the findings were similar. With were studied and again two clear-cut groups 'soft' bone osteo-arthritis neither osteotomy nor emerged; those in whom the bones looked 'hard' simple tibial plateau replacement proved reliable; (Fig. la) and those in whom they looked 'soft' continuing collapse caused failure and success (Fig. lb). The third stage of the investigation was could be obtained only by using total knee re- to try and correlate success or failure with hard- placement in which each component was ness and softness of bone. The thesis of this article anchored with cement distributing the load is that such a correlation not only exists but is widely. When the bone was 'hard' osteotomy or Postgrad Med J: first published as 10.1136/pgmj.44.517.848 on 1 November 1968. Downloaded from Hard and soft osteo-arthritis 849 Protected by copyright.

FIG. 1. 'Hard' (a) and 'soft' (b) osteo-arthritis. http://pmj.bmj.com/ on September 30, 2021 by guest.

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FIG. 2. (a) A Moore's prosthesis which has been inserted in the presence of 'soft' bone. (b) The same hip as illustrated in (a) after an interval of 3 years. The prosthesis has sunk down the shaft of the femur and into the acetabulum. Postgrad Med J: first published as 10.1136/pgmj.44.517.848 on 1 November 1968. Downloaded from 850 C. P. Broad tibial plateau prosthetic replacement were usually in which total replacement coupled with the use satisfactory. of cement ensure firm anchorage and wide dis- tribution of stress. When the bones look 'hard' Conclusions simpler methods are usually satisfactory. In choosing between the various procedures available in the surgical treatment of osteo-arth- ritis the radiographic appearance of the bones is Acknowledgment of considerable importance. If the bones look I wish to thank Mr A. Graham Apley who encouraged 'soft' the only methods likely to succeed are those me to develop this thesis. Protected by copyright. http://pmj.bmj.com/ on September 30, 2021 by guest.