Introduction. An understanding of anatomic variability can help guide the surgeon on intervention strategies. Well-functioning thumb metacarpophalangeal joints (MCPJ) are essential for carrying out typical daily activities. However, current options for arthroplasty are limited. This is further hindered by the lack of a precise understanding of the geometric variation present in the population. In this paper, we offer new insight into the major modes of geometric variation in the thumb MCP using Statistical Shape Modelling. Methods. Ten participants free from hand or wrist disease or injury were recruited for CT imaging (Ethics Ref:14/LO/1059). 1. Participants were sex matched with mean age 31yrs (range 27–37yrs). Metacarpal (MC1) and proximal phalanx (PP1) bone surfaces were identified in the CT volumes using a greyscale threshold, and meshed. The ten MC1 and ten PP1 segmented bones were aligned by estimating their principal axes using Principal Component Analysis (PCA), and registration was performed to enable statistical comparison of the position of each mesh vertex. PCA was then used again, to reduce the dimensionality of the data by identifying the main ‘modes’ of independent size and shape variation (principal components, PCs) present in the population. Once the PCs were identified, the variation described by each PC was explored by inspecting the shape change at two standard deviations either side of the mean bone shape. Results. For the ten MC1s, over 80% of the variation was described by the first two PCs (Table 1). Figure 1 shows the effect of the variation in PC1. The majority of geometric variation of the ten PP1s was also described by the first two PCs, with PC1 describing 78.9%. Figure 2 shows the effect of this component on the mean bone geometry. Both the distal articulating surface (head) of the MC1 and the proximal articulating surface (base) of the PP1 vary in overall size. However, the MC1 head also varies in shape (curvature), whereas the PP1 base does not appear to undergo noticeable variation in shape. In this study population, smaller MC1 was observed to correlate with a flatter head, whereas the PP1 head shape did not vary with size. Discussion. The flatter MC1 head (smaller height-radius ratio) may have implications for MCPJ instability, and possibly for osteoarthritic degeneration. A recent study predicted similar trends for the first CMC joint. 2. Previous investigation also observed correlation between MC1 head curvature and MCPJ RoM. 3. , which may explain clinical observations of differing thumb movement strategies. This study used a convenience sample and cannot describe a full population's variability, though the high variance captured by only two PCs suggests adequate external validity amongst similar populations. Further confidence would be gained from studying the joint (i.e. single PCA containing both bones), and wider populations. Significance. These data: provide more precise description of anatomic variation; may offer insights into thumb movement strategies and MCPJ osteoarthritic degeneration. 4. ; and support implant design for individuals whose anatomy can bear an anatomic reconstruction. For any figures or tables, please contact the authors directly

Since November 2003 there have been 62 Metacarpophalangeal Joint (MCPJ) replacements carried out on 16 patients at Macclesfield District general hospital. 11 of the patients were female and 5 were male. The mean patient age at procedure was 64.9 years, with an age range of 28 to 80. Of the 62 MCPJ replacements carried out, 58 (93.5%) were as a result of rheumatoid arthritis, with only 4 (6.5%) as a result of osteo-arthritis. The primary objective of this study is to assess their outcomes to date. Data was collected retrospectively by means of case note review. Outcomes measured were patient rating of pain and function at post operative review and post operative complications. All operations were carried out by a single surgeon, using his standard operative technique, and all replacements used the Neuflex Finger Joint Implant System. All 16 patients attended for post operative review. At the time of discharge 13 patients rated their outcome as excellent to good, 1 patient was deceased and 2 patients are currently under follow up with no reported complications. Mean time to discharge was 19 months (2–68). Of the total 62 joints replaced, 10 revisions were carried out. Of these, 3 were as a result of dislocation, 6 were for subluxation and 1 as a result of failure of the prosthesis. There were 3 other post operative complications; 1 was for superficial wound infection, 1 resulting from a prominent prosthesis and 1 hypertrophic scar. Results showed that 81.3% of patients rated their range of movement as good to excellent and 87.5% reported an improvement in pain. Overall, 81% of patients rated their outcome at discharge as good to excellent. From the data available we conclude that the Neuflex system is an effective treatment method with a low complication rate

Objective

We explanted NeuFlex metacarpophalangeal (MP) joint prostheses to identify common features, such as position of fracture, and thus better understand the reasons for implant failure.

Introduction. An educated public are becoming increasingly aware of percutaneous needle fasciotomy (PNF) for the treatment of Dupuytren's contracture. We believe that it has an important place in the management of this condition and have set up a dedicated one-stop clinic to perform this procedure. Methods. A prospective study of 61 patients with Dupuytren's, who have undergone PNF have been recruited so far. The study population includes 50 men and 11 women. The average age is 65. The senior author has operated on 81 fingers including 69 MCP joints, 62 PIP joints and 6 DIP joints. We recorded contractures prior to PNF and immediately following the procedure, as well as any complications. At follow up we recorded the Patient global impression of change (PGIC), DASH scores, degree of straightness of the operated finger and whether they would have the procedure again or recommend it. Results. For MCP joints the average pre treatment contracture was 43. o. and immediately post operatively it was 3. o. For PIP joints the average pre treatment contracture was 48. o. and immediately post operatively it was 17. o. For DIP joints the average pre treatment contracture was 41. o. and immediately post operatively it was 20. o. 8 patients had small skin tears and 2 found it too uncomfortable to continue. No nerve or tendon injuries. Mean follow up was 9 months (6–24). At follow up the average PGIC was 6 (very good) and the average DASH score was 30.9 (excellent). Subjectively the vast majority of fingers remained straight. All but 4 patients would have the procedure again and would recommend it to others. Discussion. This specialist clinic offers a very effective, safe procedure and our patients are highly satisfied withthe results. It is also cost effective for our Department

Aim. We aimed to assess the efficacy of conservative management of proximal phalanx fractures in a plaster slab. Methods. 23 consecutive patients with proximal phalanx fractures were included in this prospective study. The fractures were reduced and the position was held with a dorsal slab for three weeks. They were followed up an average of 7 weeks (range 2 to 45) after the injury. Radiographic confirmation of adequate reduction was carried out each week until union. After removal of the plaster, range of motion of the finger and radiological evidence of union, non-union or malunion was documented. Results. In united fractures, an average angulation of 4° (apex volar) was measured (range 0 to 45°). In one case (45°) this was not acceptable. All other cases measured less than 15° of angulation. On the AP radiograph the angulation was on average 2° (range 0 to 8°). On average 1.3 mm of shortening (range 0 to 5mm) were measured. In one case delayed union with rotational deformity of 20° was evident. After removal of the slab mild stiffness was noted in one case at the metacarpophalangeal joint and in two cases at the proximal interphalangeal joint. Conclusion. Most proximal phalanx fractures can be managed conservatively with acceptable results. NO DISCLOSURES

The Mathys. ¯. finger joint replacement system offers a novel fixation method into the proximal and distal medullary canals and a semi-constrained articulation. This comprises a separable, form-fit joint with a distal/proximal play of 0.7 mm, a lateral excursion of 10°, and rotation of up to 6°. This has theoretical advantages of increased radio-ulnar stability, preventing ulnar drift in patients with rheumatoid disease, and enhanced osseointegration offering implant longevity. In our unit, however, high failure rates were noted, prompting a review of cases to quantify our suspicions. Case notes of all patients who underwent finger joint replacement using the Mathys. ¯. implant between 1999 and 2005 were retrieved. Twenty-two devices were implanted by a single surgeon during this period. Four were in finger proximal interphalangeal joints, 17 in finger metacarpophalangeal joints and one in a thumb carpometacarpal joint (CMCJ). Indications for joint replacement included sixteen for rheumatoid arthritis (RA) and five for post-traumatic joint problems. The only thumb CMCJ was replaced for primary osteoarthritis. Patients were reviewed regularly and implant performance assessed critically along with survival of the implant to revision, infection or death of the patient. Mean follow up was 30 months. Sixteen implants failed including the only thumb CMCJ. Modes of failure were rotation (11), poor range of motion (two), infection (two) and dislocation (the CMCJ). Similar ball and socket designs for uncemented thumb CMCJ replacement, such as the Ledoux prosthesis, have previously shown poor survival and have been withdrawn from the market. Of the finger implants in RA patients (n=16), 12 implants failed of which ten were due to rotation. Time to failure ranged from two to 48 months (mean 15 months). The authors do not recommend the use of this implant, especially in cases of rheumatoid arthritis

Introduction. Evaluating the success of a treatment has changed. Currently, the emphasis is on patient-rated outcome scores rather than surgeon recording of outcome measures. Functional outcome and patient satisfaction following Dupuytren's disease surgery is poorly quantified in the literature. This study aimed to assess subjective patient hand function, disability and satisfaction using a PEM score and its correlation with residual contracture. Methods. Percutaneous Needle Fasciotomy (PNF) is performed in our outpatient clinic to treat Dupuytren's contracture at MCP joints. A validated patient completed questionnaire (PEM) was used to record patient demographics, side of surgery, finger involved, time since surgery, residual symptoms, disability, subjective hand function and satisfaction. The questionnaire was posted to all patients who had PNF over the study period (n=68) along with a stamped addressed envelope and participant information sheet. Results. 68 patients had PNF surgery on 73 hands. Completed questionnaires were returned from 46 patients (51 hands), a response rate of 70%. Mean follow-up was 15 months (SD +/− 10), range 5-36 months. Wilcoxon Signed Ranks Test showed that change in ‘function of hand’ over time was statistically significant (z = 5.82, n-ties = 50, p < 0.001). Spearman's test showed a significant correlation between any residual contracture and total score on the PEM (r. s. = 0.540, N=51, p <0 .001, two tailed). Multiple linear regression revealed that the correction achieved at time of surgery was a significant predictor of subjective hand function (p= 0.001). Most of the patients were satisfied with their surgery and its outcome, a cumulative mean score of 4.80 with SD +- 2.58. Conclusion. Significant improvement in contracture and deformity and good patient satisfaction can be achieved by percutaneous needle fasciotomy. Hand function measured using this tool (PEM Score) was strongly correlated with final deformity at follow-up