The By-Pass Operation for Arthritis at the First Carpometaearpal Joint--Stewart H. Harrison
THE BY-PASS OPERATION FOR ARTHRITIS AT THE FIRST CARPOMETACARPAL JOINT STEWART H. HARRISON, Windsor SUMMARY
The By-Pass operation provides a less destructive alternative to arthroplasty or arthrodesis for fixation of the firs~ carpometacarpal joint. INTRODUCTION
The first carpometacarpal joint is frequently affected in both Osteo-Arthritis and Rheumatoid Arthritis, giving rise to pain and deformity. There are two methods of treatment: one is arthrodesis, the other arthroplasty. The arthrodesis as described in this paper is an extra-articular arthrodesis using an intermetacarpal bone graft or peg, and is described as the "By-Pass Operation". Arthroplasty is performed by removal of the trapezium as practised by Clayton (1962), Flatt (1963), and Gervis (1949), and modified by Swanson (1968) and Entin (1971), who remove the trapezium and insert a prosthesis as a replacement. Kessler (1973) removes the base of the metacarpal and inserts a silicone spacer. Nalebuff (1968) recommends carpometacarpal joint arthrodesis. A case is presented in favour of the By-Pass Operation in preference to arthroplasty or true arthrodesis on the grounds that it is less destructive and need not be permanent. Bunnell (1956) states that the results of removal of the trapezium are uncertain, and the thumb is left more or less floating on the scaphoid without the best joint leverage. Kessler (1973) does not favour excision of the trapezium because of the weakness and instability which follows and emphasises the need for stability at the base of the thumb. There are anatomical and functional reasons why the trapezium should not be removed. FUNCTIONAL ANATOMY
The thumb is the most important digit in the hand and the first carpometacarpal joint is designed to provide it with mobility. Basically there are four movements: extension, flexion, abduction and adduction, and these occur at the carpometacarpal joint. This joint is a saddle-shaped joint, concave in the vertical plane and convex in the transverse. It is not multi-axial as described by some anatomical textbooks; it is bi-axial. This joint will allow movement basically in two planes: up to 90 ° palmar abduction away from the palm, and from full radial abduction to full adduction in the plane of the palm. Rotation occurs as a result of the obliquity of the joint surfaces and the laxity of the ligaments at the carpometacarpal and the first metacarpophalangeal joints. It can be seen by observing the nail that although the thumb passes from 0-90 degrees, the thumbnail in fact only rotates 45 degrees. It is probable that any rotation which takes place outside the two planes of movement previously described in the first carpometacarpal joint occurs at the scaphoid-trapezium joint. S. H. Harrison, F.R.C.S, (Eng. & Ed.), L.D.S., R.C.S.Ed., 1 Dorset Road, Windsor, Berkshire. The Hand--Vol. 8
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The By-Pass Operation for Arthritis at the First Carpometacarpal Joint--Stewart H. Harrison
Fig. 1. The scapho-trapezial joint can be affectedby arthritis. Fig. 2. Diagram to show ridge on trapezium which gives origin to short musclesof the thumb. The scaphoid-trapezium joint is concavo-convex and can also be affected by Osteo-Arthritis (see Fig. 1). The degenerative change seen in this X-ray is presumptive evidence of functional mobility. There is a well-marked ridge on the trapezium (see Fig. 2) which gives origin to three of the short muscles of the thumb, namely the abductor pollicis brevis, opponens pollicis, and flexor brevis pollicis. It also gives attachment to the transverse carpal ligament. The bone is grooved to accommodate the flexor carpi radialis which lies in a synovial sheath. It is apparent that the three short muscles most concerned with bringing tile thumb into the pre-dynamic position of function all arise from the trapezium, and removal of the trapezium will materially affect the origin of these essential muscles. At the same time, the thumb will be shortened and stability further affected by the loss of the distal attachment of the carpal ligament, and possibly the stabilising effect of the flexor carpi radialis. Finally, removal of the base of the first metacarpal will affect the insertion of the abductor pollicis longus, and accentuate the loss of stability. EFFECT ON FUNCTION Pain and/or instability at the first carpometacarpal joint leads to an adduction deformity, and this affects pinch which is changed from opposition to apposition pinch. This in turn alters the relationship of the index finger, from supination in opposition pinch, to pronation in apposition pinch, and puts an extra strain on the first interosseus muscle. If this weakens then the index finger will drift into ulnar deviation. Shortening of the thumb by removal of the trapezium reduces the effective length of the short muscles, and will therefore reduce stability. INDICATIONS
FOR OPERATION
Pain in the carpometacarpal joint can be diagnosed by passive rotation of the thumb. If this symptom is absent and the patient is complaining of pain, 146
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then direct pressure over the tubercle of the scaphoid may elicit pain, and in this case the cause is often Osteo-Arthritis of the scapho-trapezium joint. Osteo-Arthritis in the carpometacarpal joint is not uncommon and causes pain and discomfort. X-ray shows narrowing of the joint space and lipping is frequently seen. The metacarpal adducts due to muscle spasm, the base of the metacarpal subluxates dorsally and the metacarpophalangeal joint hyper-extends (Fig. 3). In Rheumatoid Arthritis the carpometacarpal joint is also frequently involved, and as a result, the first metacarpal adducts towards the second. This deformity not only alters the relationship of the thumb to the index in pinch, but produces excessive strain on the medial collateral ligament of the thumb which can rupture and give rise to subluxation with radial deviation of the thumb at the first metacarpophalangeal joint. In Rheumatoid Arthritis adduction deformity may be classified as follows: (1) Primary; (2) Secondary; (3) Paralytic. Primary adduction deformity is due to pain and destructive changes in the carpometacarpal joint, and this will ultimately lead to an adduction deformity of the thumb. Secondary adduction deformity occurs when the thumb pursues the retreating index finger in ulnar drift. Paralytic adduction deformity o c c u r s secondary to median nerve involvement, especially seen in the Carpal Tunnel Syndrome.
Fig. 3. Osteoarthritis of the carpometacarpal joint of the thumb with dorsal subluxation of the base of the metacarpal and hyperextension of the metacarpophalangeal joint. Fig. 4. Diagram of the insertion of the graft. Dotted lines indicate bone cut out, and the arrow indicates how the graft is inserted. It is locked in place with a separate piece of bone, the key. The Hand--Vol. 8
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The By-Pass Operation for Arthritis at the First Carpometacarpal Joint--Stewart H. Harrison THE O P E R A T I O N
A curved incision is made between the first and second metacarpals, and a round hole is bored in the mid-shaft of the first metacarpal on the medial side. A gutter is then cut along the lateral side of the second metacarpal. A bone graft 5 cms. long is cut from the olecranon and a separate small fragment is also removed to be used later as a key. The graft is recessed into the round hole in the first metacarpal. It is then passed through the first interosseus muscle and emergesat the distal end of the gutter on the second metacarpal. The surplus of bone is removed and the graft is then impacted down the gutter with an impacter until maximum separation of the metacarpals has been obtained. The key is then inserted to prevent the graft from slipping forwards (Fig. 4). Immobilisation in Plaster of Paris is maintained for six weeks. It has now become our practice to insert a thin sheet of silastic material into the carpometacarpal joint in order to prevent fusion occurring and also a small piece is inserted into the scaphotrapezium joint if there is any radiological evidence of destructive change or Osteo-Arthritis. In one rheumatoid patient in whom there was total disorganisation and collapse of the carpus, the graft was supplemented by a large Swanson prosthesis which entered the base of the metacarpal and proximally entered the lower end of the radius (see Fig. 5). Fig. 5 shows a bone graft soundly united. More recently a straight peg (see Fig. 6) made of Polypropylene (Harrison, 1974) has been used as an alternative to the bone graft. There are two sizes of straight peg, one of 3.5 cms. and the other of 4.5 cms. FOLLOW-UP Thirty cases have been treated: twenty-six by bone graft and four by the peg. All have been relieved of pain and deformity initially. Seventy per cent of the bone-grafts survived and no patient has complained of any disability as a result of this operation. A number of those cases treated for Osteo-Arthritis of the carpometacarpal joint in which pain was the predominating symptom, have
Fig. 5. A bone graft soundlyunited, 148
Fig. 6. Polypropylenepeg. The Hand--Vol. 8
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requested that the other thumb should be similarly treated. In thirty per cent the bone graft absorbed and in one case it fractured. Those cases that failed had a recurrence of deformity but remained free from pain. The average period for radiological evidence of absorption was six to nine months. CONCLUSION The By-Pass Operation corrects the adduction deformity and will relieve pain in both Osteo-Arthritis and Rheumatoid Arthritis. The prolonged rest tends to halt the progress of joint destruction in both Osteo and Rheumatoid Arthritis. Therefore, if the bone-graft should absorb, a recurrence of pain is not an inevitable result of this complication. The advantage of the By-Pass Operation as compared with arthroplasty by excision of the trapezium is that the thumb is not shortened and it does not interfere with the anatomical structures which form the keystone of this pillar of anatomy. It does not alter the origin of the tendons which stabilise and maintain function in this digit, and there is no irreparable damage done as occurs from the more radical procedure. REFERENCES
13UNNELL, Sterling (1956) "Surgery of The Hand", 3rd Ed. Philadelphia and Montreal. J. B. Lippincott and Company. CLAYTON, M. L. (1962) Surgery of the Thumb in Rheumatoid Arthritis. Journal of Bone and Joint Surgery, 44A" 1376-1386. ENTIN, M. A. (1971) Management of Early Rheumatoid Arthritis in the Hand. In: Surgery of Rheumatoid Arthritis. Ed. R. L. Creuss, Philadelphia, J. 13. Lippincott and Co. 165-175. FLATT, A. E. (1963) The Care of the Rheumatoid Hand. St. Louis, C. V. Mosby Company. GERVIS, W. H. (1949) Excision of the Trapezium for Osteoarthritis of the TrapezioMetacarpal Joint. Journal of Bone and Joint Surgery, 3113 537-539. HARRISON, S. H. (1974) The Harrison-Nicolle Intramedullary Peg: Follow-up Study of One Hundred Cases. The Hand, 6: 304-307. KESSLER, Isidor (1973) Aetiology and Management of Adduction Contracture of the Thumb in Rheumatoid Arthritis. The Hand, 5: 170-174. NALEBUFF, E. A. (1968) Diagnosis, Classification and Management of Rheumatoid Thumb Deformities. Bulletin of the Hospital for Joint Diseases, 29: 119-137. SWANSON, A. B. (1968) Silicone Rubber Implants for Replacement of Arthritic or Destroyed Joints in the Hand. Surgical Clinics of North America, 48: 1113-1127.
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