Implementation of ultrasonic sensing for high resolution measurement of binary gas mixture fractions

We describe an ultrasonic instrument for continuous real-time analysis of the fractional mixture of a binary gas system. The instrument is particularly well suited to measurement of leaks of a high molecular weight gas into a system that is nominally composed of a single gas. Sensitivity < 5 × 10−5 is demonstrated to leaks of octaflouropropane (C3F8) coolant into nitrogen during a long duration (18 month) continuous study. The sensitivity of the described measurement system is shown to depend on the difference in molecular masses of the two gases in the mixture. The impact of temperature and pressure variances on the accuracy of the measurement is analysed. Practical considerations for the implementation and deployment of long term, in situ ultrasonic leak detection systems are also described. Although development of the described systems was motivated by the requirements of an evaporative fluorocarbon cooling system, the instrument is applicable to the detection of leaks of many other gases and to processes requiring continuous knowledge of particular binary gas mixture fractions

Allograft-Composite Reverse Shoulder Arthroplasty for Malignant Tumor of the Proximal Humerus

International audienceComposite-allograft reverse shoulder arthroplasties are a surgical alternative in malignant tumor reconstructions following segmental bone resection of the proximal humerus. They allow reinsertion of the rotator cuff tendons and reliable restoration of humeral height, increasing prosthetic stability and mobility. Preoperative local tumor extension assessment must be thorough and a strict surgical technique must be followed to obtain satisfactory functional results. The indications for this procedure include a strictly intraosseous tumor of the proximal humerus corresponding to an S3-S4 A resection following criteria provided by the Musculoskeletal Tumor Society as described by Enneking and colleagues in 1990. Certain conditions must question the procedure such as extended S3-S4-S5 bone resections, partial sacrifice of the deltoid muscle, preoperative deltoid impairment, and glenohumeral arthrectomy. Here, we report technical details and indications of composite-allograft reverse shoulder arthroplasty in the context of tumor segmental resection of the proximal humerus, especially in the humeral preparation

Composite reverse shoulder arthroplasty can provide good function and quality of life in cases of malignant tumour of the proximal humerus

International audienceManagement of proximal humeral tumours remains a surgical challenge. No study to date has assessed the quality of life scores following the composite reverse shoulder arthroplasty for this indication. We, therefore, evaluated function and quality of life following reconstruction with allograft for malignant tumour of the humerus

Do trapeziometacarpal prosthesis provide better metacarpophalangeal stability than trapeziectomy and ligamentoplasty?

International audienceBACKGROUND:No surgical management is better than another regarding functional recovery for trapeziometacarpal joint osteoarthritis. Metacarpophalangeal (MCP) hyperextension, directly due to the shortening of thumb height, appears to be a factor of poor prognosis.HYPOTHESIS:MCP hyperextension can be corrected by implantation of a trapeziometacarpal prosthesis (TMP), as opposed to trapeziectomy and ligamentoplasty (TL), and pinch strength is greater with TMP in this indication.MATERIAL AND METHODS:Sixty-nine patients (41 TMP and 28 TL) were retrospectively evaluated. The following were evaluated: pain, mobility of the metacarpophalangeal joints, palmar grip and pinch strength. Thumb height was measured on radiographs as a post/preoperative ratio.RESULTS:The mean follow-up was 20 months (6-38). The TMP group showed greater reduction of the metacarpophalangeal hyperextension in all hyperextension groups, especially hypertension >30°, compared with TL. The TMP group provided significant greater pinch strength in all the subgroups with preoperative MCP hyperextension. Patient with postoperative MCP hyperextension had a significant lower grip and pinch strength compared with patient without MCP hyperextension. Radiographic analysis showed that thumb height changes were related to the degree of preoperative hyperextension. Postoperatively, patients with postoperative MCP hyperextension had a significant lower thumb height than patient without MCP hyperextension.DISCUSSION:Metacarpophalangeal hyperextension appears to be a factor of poor prognosis for surgical treatment of trapeziometacarpal osteoarthritis when it is not managed. TMP provides better metacarpophalangeal stabilization by restoring thumb length and would avoid surgery on the metacarpophalangeal joint. TMP may be recommended in patients having symptomatic trapeziometacarpal joint osteoarthritis and MCP joint hyperextension.LEVEL OF EVIDENCE:III, retrospective observational case control study

Modification of matched distal ulnar resection for distal radio-ulnar joint arthropathy: Analysis of distal instability and radio-ulnar convergence

International audienceBackground: In palliative surgery on the distal radio-ulnar joint (DRUJ), ulnar head resection and the Sauvé-Kapandji procedure are often followed by instability and radio-ulnar convergence. The objective of this study was to evaluate the stability of the DRUJ after modified matched distal ulnar resection performed alone or with partial or complete wrist arthrodesis.Hypothesis: A modification of matched distal ulnar resection, consisting in reconstruction of the sixth compartment and dorsalisation of the extensor carpi ulnaris, minimises these complications, regardless of the cause and associated procedures.Patients and methods: A single-centre retrospective study was conducted in 46 patients (50 wrists) who underwent modified matched distal ulnar resection. The 50 wrists fell into three groups: total wrist arthrodesis according to Millender, n=21 (TWA group); radius to proximal row arthrodesis, n=17 (RPRA group); and isolated matched distal ulnar resection, n=12 (IMDUR group). Seventy per cent of patients had rheumatoid arthritis. Each patient underwent a clinical and radiographic assessment, with an analysis of radio-ulnar convergence, DRUJ stability, and ulno-carpal impingement, as well as of ulnar translation of the carpus in the IMDUR group.Results: After the mean follow-up of 8.2±5.4 years, 62% of patients were pain-free, with a mean VAS pain score of 1.3±2.1, and 90% of patients said they would have the procedure again. Clinical and radiographic instability due to excessively proximal resection was noted in 2 (4%) wrists, of which 1 required repeat surgery. Ulno-carpal impingement due to excessively distal resection occurred in 2 (4%) wrists. No significant ulnar translation of the carpus was noted in the IMDUR group (DiBenedetto: 0.011±1.9). Range of motion was similar in the three groups (mean pronation=77±17°; and mean supination=79±8°) (p>0.05). Mean grip strength was 85±35% compared to the other side.Discussion: Our modification of matched distal ulnar resection minimises the complications specific of other ulnar head resection techniques or of the Sauvé-Kapandji procedure, namely, radio-ulnar convergence and DRUJ instability.Level of proof: IV; retrospective comparative study