Introduction. Orthopaedic and trauma surgeons not infrequently encounter the hallucal interphalangeal joint sesamoid (HIPJS) in irreducible traumatic dislocations. However, patients with the classic triad of plantar keratoma beneath a hyperextended interphalangeal (IP) joint associated with stiffness of the first metatarsophalangeal joint tend to present to podiatrists rather than orthopaedic surgeons. Methods. We present our experience with the HIPJS following first metatarsophalangeal joint (MTP1) arthrodesis in 18 feet of 16 women, aged 42 to 70 years old. Where CT scan was available, volume of the HIPJS was determined using Vitrea Software. Results. Two groups of patients were identified. Group 1 consisted of 12 feet in 11 women, who developed a painful keratoma beneath a gradually hyperextending IP joint of the great toe, at varying intervals (range 6 to 75 months) following MTP1 arthrodesis. Group 2 comprised 6 feet in 5 women who had undergone MTP1 arthrodesis but reported no symptoms in relation to an undetected and/or recognized, but unexcised HIPJS (range 15 to 97 months). We found no difference in average size of the HIPJS between Groups 1 and 2 (190.42 mm. 3. and 196.47 mm. 3. , respectively). Clinically, all toes had been fused in good position and no difference existed in the post-operative angle subtended by the proximal phalanx of the arthrodesed big toe with the first metatarsal between the 2 groups. A good outcome followed removal of metalwork and excision of the HIPJS in the symptomatic patients. Conclusion. Think of a HIPJS in the patient who presents with a painful plantar keratoma beneath a hyperextended interphalangeal joint following MTP1 arthrodesis. Do not rush into a Moberg osteotomy as this will only push the big toe higher against the toe-box. Consider prophylactic excision of a HIPJS prior to MTP1 arthrodesis

Distal interphalangeal joint (DIPJ) fusion using a k-wire has been the gold standard treatment for DIPJ arthritis. Recent studies have shown similar patient outcomes with the headless compression screws (HCS), however there has been no cost analysis to compare the two. Therefore, this study aims to 1) review the cost of DIPJ fusion between k-wire and HCS 2) compare functional outcome and patient satisfaction between the two groups. A retrospective review was performed over a nine-year period from 2012-2021 in Counties Manukau. Cost analysis was performed between patients who underwent DIPJ fusion with either HCS or k-wire. Costs included were surgical cost, repeat operations and follow-up clinic costs. The difference in pre-operative and post-operative functional and pain scores were also compared using the patient rate wrist/hand evaluation (PRWHE). Of the 85 eligible patients, 49 underwent fusion with k-wires and 36 had HCS. The overall cost was significantly lower in the HCS group which was 6554 New Zealand Dollars (NZD), whereas this was 10408 NZD in the k-wire group (p<0.0001). The adjusted relative risk of 1.3 indicate that the cost of k-wires is 1.3 times more than HCS (P=0.0053). The patients’ post-operative PRWHE pain (−22 vs −18, p<0.0001) and functional scores (−38 vs −36, p<0.0001) improved significantly in HCS group compared to the k-wire group. Literatures have shown similar DIPJ fusion outcomes between k-wire and HCS. K-wires often need to be removed post-operatively due to the metalware irritation. This leads to more surgical procedures and clinic follow-ups, which overall increases the cost of DIPJ fusion with k-wires. DIPJ fusion with HCS is a more cost-effective with a lower surgical and follow-up costs compared to the k-wiring technique. Patients with HCS also tend to have a significant improvement in post-operative pain and functional scores

Background Bony or cartilaginous ossicles appear at the plantar aspect of the interphalangeal joint of the great toe. The variation in pattern, prevalence and anatomic relationships of these structures is not clearly established in the literature, especially in a Caucasian population. Without this knowledge, pathology at this joint may be underestimated and surgical approaches may be poorly planned particularly as radiographs underestimate the incidence of ossicles at this joint. The aims of this study were to determine the incidence and pattern of ossicles at this joint and to establish their anatomical relationships in order to aid planning the approach for their excision. Method The left great toe interphalangeal joint was dissected in forty British Caucasian cadavers and the pattern of ossicles and their anatomic relationships were established. Results In 27.5% of specimens, there was no identifiable ossicle and in these cases, the tendon of flexor hallucis longus was adherent to the joint capsule. In the remaining specimens (72.5%), a bursa separated the tendon of flexor hallucis longus from the plantar joint capsule and ossicles were found embedded within the joint capsule. Over a half (52.5%) of the specimens had a single ossicle located centrally within the plantar capsule and the remaining 20% had two ossicles lying within the capsule. Conclusion This study shows that a large proportion of the population have either one or two bony or cartilaginous ossicles at this joint. In addition, the study has clarified the anatomy of this joint and shown that, when present, ossicles do not lie within the tendon of flexor hallucis longus and could be most safely approached from either a medial or lateral approach

Aims. The paediatric trigger thumb is a distinct clinical entity with unique anatomical abnormalities. The aim of this study was to present the long-term outcomes of A1 pulley release in idiopathic paediatric trigger thumbs based on established patient-reported outcome measures. Methods. This study was a cross-sectional, questionnaire-based study conducted at a tertiary care orthopaedic centre. All cases of idiopathic paediatric trigger thumbs which underwent A1 pulley release between 2004 and 2011 and had a minimum follow-up period of ten years were included in the study. The abbreviated version of the Disabilities of Arm, Shoulder and Hand questionnaire (QuickDASH) was administered as an online survey, and ipsi- and contralateral thumb motion was assessed. Results. A total of 67 patients completed the survey, of whom 63 (94%) had full interphalangeal joint extension or hyperextension. Severe metacarpophalangeal joint hyperextension (> 40°) was documented in 15 cases (22%). The median QuickDASH score was 0 (0 to 61), indicating excellent function at a median follow-up of 15 years (10 to 19). Overall satisfaction was high, with 56 patients (84%) reporting the maximal satisfaction score of 5. Among 37 patients who underwent surgery at age ≤ two years, 34 (92%) reported the largest satisfaction, whereas this was the case for 22 of 30 patients (73%) with surgery at aged > two years (p = 0.053). Notta’s nodule resolved in 49 patients (73%) at final follow-up. No residual triggering or revision surgery was observed. Conclusion. Surgical release of A1 pulley in paediatric trigger thumb is an acceptable procedure with excellent functional long-term outcomes. There was a trend towards higher satisfaction with earlier surgery among the patients. Cite this article: Bone Jt Open 2024;5(9):736–741

Introduction

Patients suffering from finger joint pain or dysfunction due to arthritis and traumatic injury may require arthroplasty and joint replacement. Single-part silicone-based implants remain the material of choice and most widely used option, although reports on their long-term clinical performance are variable. For trauma indications, patients have a high expectation of functionality necessitating the use of materials with high wear resistance and mechanical performance. A new proximal inter phalangeal (PIP) joint designed by Zrinski AG (Wurmlingen, Germany), comprising a self-mating carbon fibre reinforced polyetheretherketone (CFR-PEEK) coupling, may provide a suitable alternative. Here we describe the wear performance of the CFR-PEEK components in a PIP joint wear simulator and subsequent characterisation of the wear particles.

Osteoarthritis (OA) of the equine distal interphalangeal joint (DIPJ) is a common cause of lameness. MicroRNAs (miRNAs) from biofluids such as plasma and synovial fluid make promising biomarker and therapeutic candidates. The objectives of this study are (1) Identify differentially expressed (DE) miRNAs in mild and severe equine DIPJ OA synovial fluid samples and (2) Determine the effects of DE miRNAs on equine chondrocytes in monolayer culture. Synovial fluid samples from five horses with mild and twelve horses with severe DIPJ OA were submitted for RNA-sequencing; OA diagnosis was made from MRI T2 mapping, macroscopic and histological evaluation. Transfection of equine chondrocytes (n=3) was performed using the Lipofectamine® RNAiMAX system with a negative control and a miR-92a mimic and inhibitor. qPCR was used to quantify target mRNA genes. RNA-seq showed two miRNAs (miR-16 and miR-92a) were significantly DE (p<0.05). Ingenuity Pathway Analysis (IPA) identified important downstream targets of miR-92a involved in the pathogenesis of osteoarthritis and so this miRNA was used to transfect equine chondrocytes from three donor horses diagnosed with OA. Transfection was successfully demonstrated by a 1000-20000 fold increase in miR-92a expression in the equine chondrocytes. There was a significant (p<0.05) increase in COMP, COL3A1 and Sox9 in the miR-92a mimic treatment and there was no difference in ADAMTS-5 expression between the miR-92 mimic and inhibitor treatment. RNA-seq demonstrated miR-92a was downregulated in severe OA synovial fluid samples which has not previously been reported in horses, however miR-92a is known to play a role in the pathogenesis of OA in other species. Over expression of miR-92a in equine chondrocytes led to significantly increased COMP and Sox9 expression, consistent with a chondrogenic phenotype which has been identified in human and murine chondrocytes

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

Ten patients, who underwent treatment for complex fracture-dislocation of the proximal interphalangeal joint of finger and one patient for that of the interphalangeal joint of thumb with a modified pins and rubbers traction system, were reviewed to evaluate the clinical and functional results. Two patients had open fracture-dislocation, 5 had pilon fractures and 4 had fracture-dislocations. The system was modified to avoid rotation of the pins in the bone during joint mobilization, thus minimizing the risk of osteolysis due to friction of pins over the bone. Michigan hand scoring system was used for subjective assessment and range of motion at proximal and distal interphalangeal joints and grip strength for objective assessment. Average follow-up was 18 months (range 3 months to 28 months). The average normalised Michigan hand score was 86. Based on Michigan scores, overall hand function was rated excellent in 8 patients, good in 2 and poor in 1. Eight patients have returned to their original jobs. The average arc of flexion in the proximal interphalangeal joint was 85 degrees and in the distal interphalangeal joint it was 47 degrees. The average grip strength was 95 percent of the uninvolved side. Two patients developed minor pin site infection, which did not necessitate pin removal or any alteration in the treatment regime. There have been no cases of osteolysis, osteitis or osteomyelitis. This modification of pins and rubbers traction system has given very acceptable results with a low complication rate. It is light, cheap, effective and easy to apply

Normal digital flexion relies on flexor tendon pulleys to transmit linear muscular force to angular digital motion. Despite the critical role these pulleys play, there is a growing trend among surgeons to partially sacrifice or “vent” them during flexor tendon repair to improve surgical exposure. Although this new practice is reported to improve outcomes after flexor tendon repair, there is concern for the long-term effects of bowstringing, reduced finger range of motion (ROM) and altered tendon biomechanics. The objective of this study was to examine the effects of the application of a thermoplastic ring, acting as an “external” pulley, on flexor tendon biomechanics and finger ROM. We hypothesized that the application of an external thermoplastic ring would produce a centripetal force over the tendon to reduce bowstringing, improve finger ROM, and restore tendon loads following pulley venting. Twelve digits comprised of the index, long, and ring fingers from four cadaveric specimens were tested using a novel in-vitro active finger motion simulator. Servo-motors were used to generate motion. Loads induced by flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP), and joint range of motion were measured with each sequential sectioning of the A2, A3, and A4 flexor pulley, in comparison to a native healthy finger condition. At each finger condition, A2 and A4 external thermoplastic pulley rings were applied over the proximal phalanx and middle phalanx, respectively, to recreate A2 and A4 function. Results were recorded and analyzed using a one way repeated-measures ANOVA. Following venting of the A2, A3 and A4 pulley, proximal interphalangeal joint (PIPJ) ROM significantly decreased by 17.02 ± 8.42 degrees and distal interphalangeal joint (DIPJ) range of motion decreased by 17.25 ± 8.68 degrees compared to intact pulleys. Application of the external rings restored range of motion to within 8.14 ± 8.17 degrees at the PIPJ and to within 7.72 ± 8.95 degrees at the DIPJ. Similarly, pulley venting resulted in a 36% reduction in FDS load and 50% in FDP load compared to intact pulleys. Following application of the external rings, loads were almost restored to normal at 7% reduction for FDS load and 13% reduction for FDP load. Venting of flexor tendon pulleys significantly alters flexor tendon biomechanics and digit range of motion. The application of thermoplastic rings acting as external pulleys over the proximal and middle phalanges is an effective, inexpensive, non-invasive and reproducible therapeutic method to restore flexor tendon biomechanics and digit range of motion

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

Aim. Distal interphalangeal joint (DIPJ) arthrodesis is a well-accepted treatment of disease in the DIPJ of the hand. The ideal technique should be technically simple, quick, cheap, have minimal complications and yield a rapid return to function. Recent large published series report major complications of 11.1% and minor complications of 26% for this procedure. The study objective is to determine patient satisfaction and complication rates of DIPJ fusion using the Autofix screw (Small Bone Innovations, France), a smaller diameter headless compression screw. Methods. A standard questionnaire was devised to assess patients' overall satisfaction and complications related to the procedure. This data is compared to equivalent procedures published internationally. The patient's radiological records were reviewed to determine bone union at 7 weeks post-operation. Results. 39 fingers were fused in 29 participants. Mean follow up was 36 months (range 2–48 months). Patient satisfaction was above 90%. We had a major complication rate of 2.56%, a minor complication rate of 20.5%. There was a higher rate of complications in patients younger than 60 years of age. Discussion. Our technique for the insertion of the Autofix, headless compression screw is shown. It is a simple, quick and effective technique for the fusion of distal interphalangeal joints of all fingers; there is no ‘down-time’, and complication rates are superior to the largest series published in international literature. Furthermore, we demonstrated 100% union by 7 weeks in our patient sample. We attribute these results to 3 aspects of the procedure. 1) The Autofix screw is a smaller diameter screw than previously used for this procedure. 2) The screw generates significant compression across the fusion site. 3) We utilise bone graft as part of our routine management. NO DISCLOSURES

The authors report their results of “extension-block Kirschner wire fixation” for the treatment of mallet finger fracture. This technique should be considered in presence of a large bone fragment involving more than the 30% of the articular surface, with or without palmar subluxation of the distal phalanx. A modification of the extension-block technique is described reducing the fragment to 0° extension of the distal interphalangeal joint. The results confirmed the better outcomes of this modification, minimizing the postoperative extension lag at the distal interphalangeal joint. The Wehbe and Schneider method was used to classify the mallet finger fractures and the results were graded according to Crawford’s criteria (66,6% excellent and 33,4% good). The extension-block K wire technique, when properly applied, is a very helpful procedure avoiding the risks and complications of the open surgery and achieving a good indirect anatomical reduction of the fracture

A retrospective analysis was done on 20 cases of interphalangeal joint fusion of the great toe utilizing longitudinal cortical screw fixation. The purpose of this study was to present a series of interphalangeal joint fusion great toe done in both paediatric and adult patients using 3.5mm cortical screws. Most of the patients had interphalangeal joint fusion along with Jones transfer and other associated procedures with a mean follow up period of 19 months. Arthrodesis was successfully achieved in all the patients. No one had pain at the interphalangeal joint of the great toe. A literature review on interphalangeal joint arthrodesis was done and advantages of cortical screw fixation over other techniques have also been presented

Purpose of the study: Duplication of the thumb is the most common congenital anomaly of the first ray. The characteristic feature of type IV is the diversity of the clinical forms and the presence of certain complex forms particularly difficult to treat (Hung IVD). We propose a new procedure for reconstruction of IVD type thumb duplication. Material and method: This new procedure was used for thumb reconstruction in two boys with type IVD thumb duplication. Mean age at surgery was 10 months. Surgical technique. The future incisions were traced with a central skin resection removing the most hypoplastic nail entirely (generally the radial nail). At the bone level, a longitudinal osteotomy of the proximal phalanges was made over the entire length to remove the central part and obtain a width for the first phalanx comparable to that of the contralateral thumb. An oblique osteotomy was cut in the base of the distal phalanx of the ulnar hemithumb with resection of a radial corner. The same type of osteotomy was performed at the base of the distal phalanx of the radial hemithumb, but with preservation of the radial corner and resection of the rest of the radial thumb. The proximal hemiphalanges were sutured as were the bases of the distal phalanges. This produced automatic realignment and stabilisation of the interphalangeal joint without an ungueal intervention. Results: The three children were reviewed at 24, 18 and 12 months. The Horii score was good in all cases. Discussion: Type IVD duplications of the thumb are difficult to treat and may leave serious sequelae. Our technique is based on the principle of a central resection of the proximal phalanges associated with partial resection of the base of the distal phalanges. This enables realignment and stabilisation of the interphalangeal joint while avoiding the problem of ungueal dystrophy since only one nail is preserved. Our preliminary results are encouraging but must be confirmed with a longer term study

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

Introduction. Mallet toe is a flexion deformity of the distal interphalangeal joint of the lesser toe. It causes pain and callosity in the toe tip and the dorsum of the distal interphalangeal joint. Campbell refers to the “terminal Syme’s amputation” for this condition but the results of this have not previously been reported. Material and Methods. This is a retrospective review of 35 toes in 22 patients that underwent distal phalangectomy. Sixteen patients were aged over 70. Patients were interviewed by an independent observer regarding the pain relief, cosmetic acceptability and satisfaction with the procedure and were examined for callosity, stump tenderness, sensitivity and neuroma. Results. All patients were satisfied including pain relief and cosmetic acceptability at an average follow up of 4.6 years. One patient had mild wound infection. One patient had asymptomatic nail growth. No stump tenderness, sensitivity or neuroma was noted. Discussion and Conclusion. Coughlin reported a satisfaction rate of 89% and 86% following successful fusion and excision arthroplasty respectively. In this series all patients were satisfied. We feel that distal phalangectomy is an option in a selected group of elderly patients where pain relief and functional outcome is the priority

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