Aim

The purpose of this study was to investigate the effects of plaster/splint immobilisation of the knee/ankle on driving performance in healthy individuals.

Objective

Retrospective study to assess the outcomes of ulnar shortening for TFCC tear and distal radial malunion.

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for uncemented thumb CMCJ replacement, such as the Ledoux prosthesis, have previously shown poor survival and have been withdrawn from the market.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.

Background: Thumb carpalmetacarpal joint (CMCJ) osteoarthritis has been treated using various combinations of resection, interposition and replacement arthroplasties. The procedure of choice for various stages of CMCJ osteoarthritis remains controversial. This study compares the short term outcomes of trapeziectomy alone and trapeziectomy with PI2 implantation.

Methods: A cross-sectional observational study involving 33 patients (36 thumbs). 18 thumbs had trapeziectomy alone and 18 had trapeziectomy and PI2 implantation. Underlying indication was osteoarthritis in 35 thumbs and trauma in one thumb. Preoperative radiological assessment using the Eaton and Glickel grading for CMCJ osteoarthritis and clinical review including DASH and SF-36 score was performed at a mean follow-up of 18 months. Preoperative and postoperative pain level was assessed using Visual Analogue Scale (VAS) and satisfaction of the surgery using the Likert 5-point scale.

Results: There were 30 women and 3 men. The average age at follow up was 61 years (range 45 to 75). There was no significant difference between the two groups regarding age, duration of symptoms, and stage of disease, preoperative pain score and handedness. The mean DASH score at follow up was 26.8 for trapeziectomy alone group and 35.4 for the PI2 arthroplasty group. Preoperative to postoperative VAS for pain showed an improvement from fair to excellent in 60% of patients in trapeziectomy alone group and 30% of the patients in the PI2 arthroplasty group. There was no significant difference in the SF-36 scores between the two groups in all health domains. 6 out of 16(38 %) patients in the PI2 group had multiple surgeries mainly due to dislocation or subluxation of the implant. The overall Likert 5-point scale scores were highest for trapeziectomy alone group with 70% very satisfied compared to 40% in the PI2 arthroplasty group.

Conclusion: The early results of pyrocarbon PI2 arthroplasty show a high complication rate compared to simple trapeziectomy. The high rates of subluxation and dislocation observed in the early cohort resulting in multiple surgeries may be attributed to steep learning curve of the surgical technique and creation of a shallow groove for the implant. This may have contributed to the low satisfaction levels observed in PI2 arthroplasty group. Simple trapeziectomy provides satisfactory outcome in more than 80% of the patients.