Bone-cement interface strength in distal radii using two medullary canal preparation techniques: carbon dioxide jet cleaning versus syringed saline.

PURPOSE: Loosening is an important cause of failure of upper limb arthroplasty and improvement in cementation techniques may limit this. The currently accepted medullary canal preparation techniques use saline washing and gauze drying. Another method of bone preparation uses carbon dioxide compression gas jet which blows debris from the canal, whilst simultaneously drying the bone. We compared the push out strengths of cement plugs in sections of human cadaveric radii that had been prepared using either syringed saline or carbon dioxide jet cleaning. METHODS: Following bone preparation, four radii in each group, were cemented in a standardised fashion, and cut into 1 cm sections. An Instron materials testing machine was used to measure the force needed to push the cement plug out of the bone section. RESULTS: The force needed to push out the cement plug was significantly higher in the carbon dioxide jet (median 580.61, IQR 429.10-650.05) as compared to the saline group (median 366.57N, IQR 271.05-502.23), P = 0.009. The mechanism of failure of the bone-cement interface also differed between the two groups, with 100% of the sectioned cortices fracturing prior to cement extrusion in the carbon dioxide jet group, but only 23% of the sectioned cortices doing so in the saline group. CONCLUSION: Our results suggest that there is a statistically stronger macro-interlock at the bone-cement interface after preparation of the medullary canals of radii using a carbon dioxide compression gas jet as compared to saline irrigation.

Undisplaced scaphoid waist fractures: is 4 weeks' immobilisation in a below-elbow cast sufficient if a week 4 CT scan suggests fracture union?

This prospective study investigated a cohort of 59 scaphoid waist fractures which were treated nonoperatively in a below-elbow plaster cast for 4 weeks and then underwent a Week 4 CT scan to assess displacement and progress to union. Forty-three were classed as undisplaced and 37 of these 43 were also classed as 'united'. All the 37 undisplaced and 'united' fractures united with up to 8 weeks' cast immobilisation, including 26 which were taken out of plaster at 4 weeks and mobilised. We conclude that scaphoid waist fractures which appear to be undisplaced and united on a week 4 CT scan will unite, and may not need to be immobilised in a plaster cast for more than 4 weeks. Such a treatment policy may reduce the period of disability and time off work associated with nonoperative treatment.

An assessment of the tensile properties and technical difficulties of two- and four-strand flexor tendon repairs.

This study compares the mechanical properties of locking Kessler and four-strand flexor tendon repairs and examines for difficulties related to technical ability. Two trainee surgeons each carried out 10 locking Kessler and 10 four-strand single-cross flexor tendon repairs on an in vitro porcine model. Outcome measures included gap formation and ultimate forces, operative time and repair bulk. Ultimate force was 81% greater for the four-strand repair compared to the Kessler (52 N, SD 5, versus 29 N, SD 6). Operating times were similar between the two techniques (Kessler 10.0 minutes, four strand 10.1 minutes). Rupture force and operating times improved slightly during the study for the Kessler repairs, but in the four strand repairs results remained stable throughout the study. We conclude that the single-cross four-strand repair tolerates superior loads yet is no more technically demanding than the modified Kessler, and can be reliably performed without additional operating time.

Arthroplasty of the shoulder in rheumatoid arthritis with rotator cuff dysfunction.

We carried out a retrospective analysis of 17 total shoulder replacements using the reversed Delta III prosthesis in patients with rheumatoid arthritis of the glenohumeral joint complicated by rotator cuff dysfunction. Outcome was assessed using the Constant-Murley scoring system. In addition, general health status was assessed with the Short Form Health Survey and radiographical analysis of the prostheses undertaken. Mean age at the time of surgery was 64 years. Thirteen shoulders were followed up for more than 5 years (mean 87 months). Median Constant-Murley score was 59.0; median scores for general health were 33.40 and 49.36 for the physical and mental components respectively. Radiographical analysis revealed evidence of lucencies about the humeral component in all cases and about the glenoid component in five cases. Despite the good clinical results, the high incidence of radiographical lucencies is of concern.

Comparison of weight changes after total hip or knee arthroplasty.

A prospective study of the effect on weight in 192 patients after total hip arthroplasty (THA) (124 hips) or total knee arthroplasty (TKA) (68 knees) was performed. Patients' weights at 1 year after THA or TKA were compared with their preoperative weights. There was little or no effect on a patient's weight after TKA. Women undergoing THA gained on average 3.1 kg (6.8 lb), whereas men gained on average 2.5 kg (5.5 lb). This information may be of benefit to a surgeon whose patient needs encouragement to lose weight before undergoing a THA.

A clinical grading system for Dupuytren's contracture.

A clinical classification for Dupuytren's contracture of the hand is described. The classification system has been used to sort patients with Dupuytren's contracture into five broad surgical categories and takes into account predisposing factors, risk of recurrence and sympathetic tone in the individual patient. The system has many advantages in determining the approximate operation time and surgical experience required to treat patients. One hundred and four patients graded by this system have been analysed. There was a broad agreement between expected and actual operating times, with no significant difference between them.

A mechanism for entrapment of the tibialis posterior tendon in lateral subtalar dislocation.

The entrapment of the tibialis posterior tendon causing a block to reduction of lateral subtalar dislocation is recognized. The mechanism which allows tendon excursion is less clearly understood. We present a case in which extensive tearing of the musculotendinous junction of the tibialis posterior muscle occurred during tendon displacement and entrapment in lateral subtalar dislocation. In view of this previously poorly recognized finding the two theories regarding entrapment are discussed. Recognition of the cause of the tendon lengthening with an intact flexor retinaculum allows appropriate early treatment.