Partial arthroscopic trapeziectomy with or without ligament reconstruction to treat primary thumb carpometacarpal joint osteoarthritis.

Many surgical options have been proposed for the treatment of first carpometacarpal (CMC1) osteoarthritis. Conventional techniques are invasive, so we wanted to develop an arthroscopic technique. Partial trapeziectomy combined with various interpositions and ligament reconstruction is a long-standing intervention. As in total trapeziectomy, the combination with ligament reconstruction remains controversial. The aim of this study was to demonstrate the benefits of adding an abductor pollicis longus (APL) ligament reconstruction to partial trapeziectomy performed under arthroscopy. This study analyzes the results of two consecutive case series carried out by a single surgeon. Thirty-four patients underwent an isolated partial trapeziectomy and 49 patients underwent partial trapeziectomy with ligament reconstruction using the APL. The patients were reviewed with an average follow-up of 3.7 years (13 months to 8.6 years) by an independent observer. The assessment included the analysis of pain, thumb appearance, QuickDASH score, Nelson Hospital score, and measurements of mobility and strength. For all patients, there was a marked reduction in pain (7.13 preoperatively vs.1.37 postoperatively) with 71% of patients having a painless thumb, the Nelson (11.14) and QuickDASH (17.89) scores as well as a clinical improvement in mobility and grip strength (14.5 KgF preop vs. 19.6 KgF postop) and key pinch (4.4 KgF preop vs. 5.4 KgF postop). The mean recovery time was 18.8 weeks. Eighty-four percent of patients were satisfied with the procedure with 90% having a stable thumb. No CRPS was found. However, the results were better for patients who underwent ligament reconstruction. There was a significant gain in grip strength, better first web opening and a lower percentage of painful thumbs. The other items were also slightly improved, but not significantly (Nelson Hospital score, QuickDASH score, key grip strength, percentage of stable thumbs, subjective thumb value estimated by patients). This technique is a less aggressive treatment of CMC1 osteoarthritis, with simplified and rapid rehabilitation. The addition of ligament reconstruction using the APL appears useful. The advantages of arthroscopy are a less painful postoperative course, low morbidity, ligament conservation, along with better access to remove loose bodies, osteophytes and to perform synovectomy. Partial trapeziectomy, which is especially indicated when the scaphotrapeziotrapezoid joint is not symptomatic, is much less used than total trapeziectomy; however, it is an attractive surgical option for young patients with significant functional demands. Arthroscopic partial trapeziectomy is a safe and reliable procedure.

PHARAO laser source flight model: design and performances.

In this paper, we describe the design and the main performances of the PHARAO laser source flight model. PHARAO is a laser cooled cesium clock specially designed for operation in space and the laser source is one of the main sub-systems. The flight model presented in this work is the first remote-controlled laser system designed for spaceborne cold atom manipulation. The main challenges arise from mechanical compatibility with space constraints, which impose a high level of compactness, a low electric power consumption, a wide range of operating temperature, and a vacuum environment. We describe the main functions of the laser source and give an overview of the main technologies developed for this instrument. We present some results of the qualification process. The characteristics of the laser source flight model, and their impact on the clock performances, have been verified in operational conditions.

Optimization of bone-block positioning in the Bristow-Latarjet procedure: a biomechanical study.

BACKGROUND: In the Bristow-Latarjet procedure, optimal positioning of the coracoid bone-block on the anterior aspect of the glenoid (standing or lying on the glenoid rim) remains debated. A biomechanical study assessed the effect of the position of the bone-block with its attached conjoint tendon on anterior and inferior stabilization of the humeral head. MATERIALS AND METHODS: The Bristow-Latarjet procedure was performed on 8 fresh cadaveric shoulders. The bone-block size was systematically at 2.5×1×1 cm. Anterior translation of the humeral head was stress induced under 30-N traction, in maximum external rotation at 0° and at 90° abduction: respectively, adduction and external rotation (ADER), and abduction and external rotation (ABER). Under radiological control, displacement of the center of the humeral head was compared with the glenoid surface at the 3, 4 and 5 o'clock (medial, antero-inferior and inferior) positions for the 2 bone-block positionings. RESULTS: The lying position at 4 o'clock substantially decreased anterior and inferior displacement of the humeral head respectively in ADER and ABER; and in ABER it also tended to decrease anterior translation, but not significantly. The standing bone-block position did not affect translation. CONCLUSIONS: Positioning the bone-block so that it lies on the anterior aspect of the glenoid in the middle of the antero-inferior quarter of the rim at 4 o'clock can decrease anterior displacement of the humeral head and inferior glenohumeral translation, especially in ADER for anterior displacement and in ABER for inferior displacement. STUDY DESIGN: Laboratory study.

Partial arthroscopic trapeziectomy with ligament reconstruction to treat primary thumb basal joint osteoarthritis.

Since the outcome of partial trapeziectomy is not always satisfactory, we proposed using arthroscopy to perform partial trapeziectomy and to perform ligament reconstruction with the abductor pollicis longus tendon. A tendon strip was left intact at its insertion at the base of the first metacarpal and then slipped into the trapeziectomy space. It was fixed into a blind tunnel at the base of the second metacarpal with a bioabsorbable interference screw. Forty-nine patients were surgically treated between 2006 and 2009. With an average follow-up of 3.6 years, 83.5% of patients were satisfied with the procedure; 96% of thumbs were stable and 74% were pain free. The average recovery time was 4.5 months. There were four cases of radial nerve branch irritation and one case of flexor carpi radialis tendinitis; there were no cases of complex regional pain syndrome. This minimally-invasive technique is a less-aggressive treatment approach for thumb carpometacarpal joint arthritis, which simplify postoperative recovery.