1 . The extensor assembly of the fingers consists of the central tendon joined by three pairs of components: a) the retinacular ligaments, which link the movements of the interphalangeal joints; b) the "wing" tendons, a lumbrical on the radial side, and usually a palmar interosseous on the ulnar side; c) the phalangeal tendons, usually dorsal interossei. 2. The retinacular ligaments are relaxed in full extension of the proximal interphalangeal joints and are, in this position, unable to extend the distal joints fully. This is because the interphalangeal joint surfaces are eccentric. 3. The pull of the wing tendons alters the shape of the extensor expansion and transfers the pull of the long extensor tendon from the base of the middle phalanx to the base of the distal phalanx, thus enabling full extension of the distal joint to be powerfully achieved. 4. The action of the lumbrical muscle, as an extensor of the interphalangeal joint, is demonstrated by a diagram showing its site and length in the various positions of the finger, calculated from the known excursions of the tendons. This is consistent with the observations on action potentials. 5. The phalangeal tendons of the dorsal interossei have a bifid insertion, a) into the phalangeal tubercle at the base of the proximal phalanx, and b) into the transverse band, and hence to the central tendon. The muscle acts at one or both of these attachments, according to the positions of the metacarpo-phalangeal and interphalangeal joints, in its varying functions of flexion, abduction and hyperextension. Finally an explanation of the deformity of clawing in ulnar palsy is given

We reviewed 13 patients with a complex fracture-dislocation of the proximal interphalangeal joint of a finger and one patient with a complex fracture-dislocation of the interphalangeal joint of thumb. We had treated these injuries using a pins and rubbers traction system which had been modified to avoid friction of the pins against the bone during mobilisation of the joint in order to minimise the risk of osteolysis. A Michigan hand outcome questionnaire was used for subjective assessment. The active range of movement (AROM) of the proximal and distal interphalangeal joints and the grip strength were used for objective assessment. The mean follow-up was 34 months (12 to 49). The mean normalised Michigan hand outcome score was 84. The mean AROM of the proximal interphalangeal joint was 85° and that of the distal interphalangeal joint 48°. The mean grip strength was 92% of the uninvolved hand. Twelve patients have returned to their original occupations. There has been no radiological osteolysis or clinical osteomyelitis. This modified traction system has given acceptable results with a low rate of complications. It is light, cheap, effective and easy to apply

1. The intrinsic paralysis that occurs in leprosy has been treated by the sublimis transfer of Stiles and Bunnell for the past nine years. Since 1951 300 hands have been operated upon, and 150 patients selected geographically have been followed up in this study. 2. The patients have been assessed by a standard method involving: 1) Measurement of range of movement of the interphalangeal joint (unassisted movement, assisted active movement and passive movement); 2) grasp index; and 3) photographs of each hand in six standard positions. 3. Assessment of the open hand—The Stiles-Bunnell procedure is effective in achieving a fully open hand: 73 per cent of the fingers scored good or excellent results. A defect in the operation is that it sometimes hyperextends the interphalangeal joint, producing an "intrinsic plus" hand. 4. Assessment of sequence of joint flexion—The Stiles-Bunnell operation restores satisfactory mechanism of closure of the hand in 93 per cent of cases—that is, the metacarpo-phalangeal joints flex before the interphalangeal joints. 5. The closedfist assessment—About 30 per cent of patients had some defect in the complete closure of the fist after operation. In 5 per cent of cases the fingers did not reach the palm after operation. 6. Complications—The "intrinsic plus" defect is commonest in the best and most mobile hands. This is a late complication which gets worse in succeeding years. It can be corrected by Littler's operation together with a profundus tenodesis in the middle segment of the finger. Lateral deviation of fingers due to radial-side attachment of the transferred tendon can be avoided by ulnar-side attachment of the tendon used for the index finger. Bowstringing of the sublimis stump in the flexor sheath may be avoided by division of the sublimis at it insertion. Weakness of grasp and pinch from loss of sublimis may be avoided by using only one or two sublimis tendons split into several strands. The index finger sublimis should be left in position. 7. It is concluded that the sublimis transfer of Stiles and Bunnell is a very powerful corrective of intrinsic paralysis of the fingers. Its chief defect is that it is too powerful and produces the opposite deformity. For this reason the use of this operation should be restricted to fingers in which there is some limitation of passive extension. For fully mobile fingers an operation should be selected which does not remove the sublimis from its normal position

We treated 32 displaced mallet finger fractures by a two extension block Kirschner-wire technique. The clinical and radiological outcomes were evaluated at a mean follow-up of 49 months (25 to 84). The mean joint surface involvement was 38.4% (33% to 50%) and 18 patients (56%) had accompanying joint subluxation. All 32 fractures united with a mean time to union of 6.2 weeks (5.1 to 8.2). Congruent joint surfaces and anatomical reduction were seen in all cases. The mean flexion of the distal interphalangeal joints was 83.1° (75° to 90°) and the mean extension loss was 0.9° (0° to 7°). No digit had a prominent dorsal bump or a recurrent mallet deformity. We believe that this technique, when properly applied, produces satisfactory results both clinically and radiologically

1. The range of variation in the movements at the metatarso-phalangeal and interphalangeal joints of the big toe in fifty males has been investigated by means of lateral radiographs. 2. In the "neutral" position the proximal phalanx is dorsiflexed on the metatarsal and the distal phalanx dorsiflexed on the proximal. Sometimes the distal phalanx is plantar flexed on the proximal but this is not associated with any obvious abnormality of function. 3. There is a wide variation between individuals in the amount of movement found at these joints. 4. At the metatarso-phalangeal joint dorsiflexion is much more free than plantar flexion. The opposite is the case at the interphalangeal joint. 5. There is no significant difference between the right and left sides. Only in plantar flexion at both joints are there significant reductions in the range of movement in older age groups. These reductions are not functionally important. 6. There is an inverse relationship between active and passive dorsiflexion: the greater the range of active dorsiflexion, the less is the range of additional passive dorsiflexion. 7. In lateral radiographs the head of the metatarsal is always rounded

We reviewed the results of reconstruction of 97 upper limbs in a consecutive series of 57 tetraplegic patients, treated from 1982 to 1990. Of these, 49 had functional and eight had cosmetic reconstructions. The principal functional objectives were to provide active elbow extension, hook grip, and key pinch. Elbow extension was provided in 34 limbs, using deltoid-to-triceps transfer. Hook grip was provided in 58 limbs, mostly using extensor carpi radialis longus to flexor pollicis longus transfer, and key pinch in 68, mostly using brachioradialis to flexor pollicis longus transfer. Many other procedures were employed. At an average follow-up of 37 months, 70% had good or excellent subjective results, and objective measurements of function compared favourably with other series. Revisions were required for 11 active transfers and three tenodeses, while complications included rupture of anastomoses and problems with thumb interphalangeal joint stabilisation and wound healing. We report a reliable clinical method for differentiating between the activity of extensor carpi radialis longus and brevis and describe a successful new split flexor pollicis longus tenodesis for stabilising the thumb interphalangeal joint. Bilateral simultaneous surgery gave generally better results than did unilateral surgery

1. The claw position of a finger with intrinsic paralysis is caused by the blocking effect of the transverse lamina on the long extensor. This starts as soon as the metacarpo-phalangeal joint is hyperextended, and increases with further hyperextension. Thus the long extensor loses its pull on the interphalangeal joints and allows them to flex. Therefore, in intrinsic paralysis the claw position can be prevented or cured by keeping the metacarpo-phalangeal joint in flexion, however slight, which can be done by splinting, by tenodesis or by capsulorrhaphy. 2. Replacement of the intrinsics by some active element, although it may improve the action of the fingers, is not necessary for the correction of claw finger. The function of the intrinsics in the prevention of claw finger is not to be found in their extending effect on the interphalangeal joints, but in the flexion effect on the metacarpo-phalangeal joint, or at least in preventing its hyperextension. This is in accordance with the fact that loss of intrinsic function is disastrous only in supple fingers, in which the metacarpo-phalangeal joints tend to assume extreme degrees of hyperextension (Riordan 1953, Brand 1958). In such fingers, the wide range of hyperextension available at the metacarpo-phalangeal joints is, of course, part of a generalised laxity of the soft parts of the fingers. These soft parts generally tend to counteract the tendency to clawing; the less their resistance, the more the human finger as a whole will tend to behave like a musculo-articular model, and such a model without intrinsics will always immediately assume the claw position

1. The range of variation in full extension at the interphalangeal and metacarpo-phalangeal joints of the thumbs of 133 male and 100 female Europeans, and of 31 male Indians and 30 male Africans, has been investigated. 2. There is considerable variation between individuals in the maximum extension of both joints of the right and left thumbs in all groups studied. 3. The distribution for each joint in both thumbs in all groups is fairly symmetrical. 4. There is a high correlation between the right and left thumbs for both joints in all groups. 5. The mean angle of extension at the right and left metacarpo-phalangeal joints in all groups is similar. Female Europeans, however, show a significantly greater mean angle than male Europeans. 6. The mean interphalangeal angle of extension in male Europeans is significantly greater than that in female Europeans and the mean in the Indian and African groups is significantly greater than in the male European group. 7. There is slight negative correlation between the metacarpo-phalangeal angle and interphalangeal angle in each thumb in the European groups. 8. Many subjects in all groups can increase extension at the metacarpo-phalangeal joint after flexing the carpo-metacarpal joint. Marked hyperextension (over 40°) is more frequent in the left than in the right thumb, in females than in males, and in male Indians than in male Europeans and Africans. 9. Maximum extension at the interphalangeal joints is not related to the presence of a sesamoid bone in the anterior part of the capsule of the joint. 10. The surfaces of the metacarpo-phalangeal joints vary considerably in shape. Those which are flat form about 10 per cent. of the sample and do not show hyperextension. 11. The factors influencing the amount of extension at the interphalangeal joint is the degree of laxity of the anterior capsule. The problem at the metacarpo-phalangeal joint is more complex; both the capsule and the shape of the joint surfaces play important roles

We randomised 79 patients (84 hands, 90 fingers) with Dupuytren’s contracture of the proximal interphalangeal joint to have either a ‘firebreak’ skin graft (39 patients, 41 hands, 44 fingers) or a fasciectomy (40 patients, 43 hands, 46 fingers) if, after full correction, the skin over the proximal phalanx could be easily closed by a Z-plasty. Patients were reviewed after three, six, 12, 24 and 36 months to note any complications, the range of movement and recurrence. Both groups were similar in regard to age, gender and factors considered to influence the outcome such as bilateral disease, family history, the presence of diabetes, smoking and alcohol intake. The degree of contracture of the metacarpophalangeal and interphalangeal joints of the operated fingers was similar in the two groups and both were comparable in terms of grip strength, range of movement and disability at each follow-up. The recurrence rate was 12.2%. We did not identify any improvement in correction or recurrence of contracture after firebreak dermofasciectomy up to three years after surgery

A case is reported of a young girl who presented with macrodactyly of the right middle finger and tumour masses on the palmar side of both interphalangeal joints. The lesions were fibrocartilaginous and appeared to be hyperplastic palmar plates. The macrodactyly and the hyperplasia of the palmar plates were attributed to trauma

1. An investigation of interdigital clavus or corn does not support the opinion that it is found most often in the web of the fourth interspace. 2. Most occur in that interval, but less than a third involve the web. 3. The commonest site is the area of impingement of the distal interphalangeal joint of the fifth toe on the proximal interphalangeal joint of the fourth

1. From India a family is reported in which fifteen of fifty-seven were affected by the nail-patella syndrome. 2. Additional coincidental features not described previously were fiexion deformities of both hips and hyperextension of the interphalangeal joints of the fingers. 3. Patients affected by the condition do not always show the same blood group

There are many operations for hallux valgus and hallux rigidus, but Keller's operation remains one of the most popular, particularly for the older patient. A prospective trial was carried out to compare the results of Keller's operation modified by Kirschner-wire distraction with those of the standard operation. The results suggest that there is no advantage in using temporary Kirschner-wire distraction; indeed, degenerative changes in the interphalangeal joint and a subjectively worse result may result from its use

Immobilisation of the thumb is widely believed to be important in the management of fractures of the carpal scaphoid. To assess the need for this, we randomly allocated 392 fresh fractures for treatment by either a forearm gauntlet (Colles') cast, leaving the thumb free, or by a conventional 'scaphoid' plaster incorporating the thumb as far as its interphalangeal joint. In the 292 fractures which were followed for six months, the incidence of nonunion was independent of the type of cast used

This annotation reviews current concepts on the three most common surgical approaches used for proximal interphalangeal joint arthroplasty: dorsal, volar, and lateral. Advantages and disadvantages of each are highlighted, and the outcomes are discussed.

Cite this article: Bone Joint J 2022;104-B(12):1329–1333.

1. A review of intra-articular and peri-articular fractures of the phalanges has been carried out, and the late results of such injuries have been examined. 2. These fractures usually unite by bone. 3. The results of conservative treatment by immobilisation are satisfactory in the case of mallet fractures, hyperextension sprain fractures and collateral avulsion fractures of the proximal phalanges. 4. The less satisfactory results after collateral avulsion fractures of the interphalangeal joints and avulsion fractures complicating dislocations are discussed

We reviewed 31 patients at a mean of five years after mallet deformity of the finger had been treated with a thermoplastic splint. Intra-articular fractures were present in 35% of patients. Osteoarthritic changes had developed in 48%, most in association with fracture, and 29% had a swan-neck deformity. There was a loss of extension greater than 10° in 35%; the average deficit at the interphalangeal joint was 8.3° and the average flexion arc was 48.5°. Despite these findings, patient satisfaction was generally high, with little evidence of functional impairment

1. Trigger thumbs present at birth can be safely watched for twelve months because there is an expected spontaneous recovery rate of at least 30 per cent. 2. Trigger thumbs in children first noticed between the age of six to thirty months can be safely watched for six months because there is an expected spontaneous recovery rate of about 12 per cent. 3. Delayed operation left no residual contracture of the interphalangeal joint provided the release was done before the age of four years. 4. Operation is recommended if the child is over the age of three years when first seen

External fixation is useful for the treatment of selected injuries to the hand. Some authors have suggested that external fixation of a phalanx may tether the extensor hood, thereby hindering active movements and predisposing to permanent adhesions. There is no consensus as to the best site for placement of the pin to minimise these problems. This study was performed on cadaver specimens to investigate the influence of the pin site on the range of simulated active movement of the interphalangeal joint. The dorsal midline position produces least interference with the extensor mechanism; radial and ulnar to this, interdigitating oblique fibres prevent a clean longitudinal split in the direction of gliding thus limiting movement of the extensor hood. At the proximal phalanx, positioning of the pin just off the midline avoids the thickening of the proximal median hood, whereas at the middle phalanx, a true midline position utilises the bare area at its base

We examined prospectively 4719 newborn infants to determine the congenital incidence of trigger thumb. No cases were found. Fifteen other children aged from 15 to 51 months had surgery for this condition. The anomaly had not been seen at birth and all thumbs presented with a flexion contracture without triggering. The condition is usually seen after birth as a flexion contracture of the interphalangeal joint. The term ‘congenital’ is a misnomer because patients acquire the deformity after birth. The term ‘trigger’ is inaccurate as most thumbs show a fixed-flexion contracture without triggering. We suggest that rather than ‘congenital trigger thumb’ a more appropriate description of this disorder is ‘acquired thumb flexion contracture in children’. If the contracture persists after one year of age, treatment by dividing the A-1 pulley is simple and effective