Purpose: Disposable medical devices have several advantages and are widely used. But since the financial burden of disposable devices is however significant for the hospital budget, it would be interesting to reassess multiple use devices in terms of efficacy and safety. The purpose of this study was to determine the safety aspects involved and to assess wear observed in new versions of autoclavable shavers and drill bits used in arthroscopic surgery.

Material and methods: After standard preparation and ten sterilisation cycles, fifteen instruments (shavers and drill bits) were used 10 times each during arthroscopic procedures performed on non-embalmed cadavers. The instruments were used on tissues, cartilage or tendons (shavers) or cancellous bone (drill bits). Duration of use was at least 10 min for each instrument. The instruments underwent standard preparation (decontamination-cleaning-immersion in 1N caustic solution) followed by sterilisation at 134°C for 20 minutes as defined by the regulatory decree (n° 138, 14 March 2001). A tracability sheet was completed at each order for sterilisation. The first phase consisted in an evaluation of the instrument’s resistance to sterilisation treatments, in particular the non-alteration of the cutting surface examined under optical magnification. The second phase was to determine the feasibility and performance level of the cleaning step based on assay of protein residue with UV spectrophotometry as described by Bradford.

Results: One hundred fifty complete cycles were performed. The results of the first phase demonstrated satisfactory instrument resistance to 10 uses with traces of erosion visible on 20% of the instruments after the 5th use. Two instruments were replaced during the study due to mechanical wear. The second phase revealed positive results in 2% of the cases (residual proteins > 8 μg/ml), the positivity threshold defined by the Pr EN ISO 15883-1 normalisation project concerning general requirements for desinfecting cleaners. Analysis of these results demonstrated that 12% of the instruments cleaned with ultrasounds carried traces of protein residues. There was no trace of proteins on instruments cleaned with a washing machine operating on the “endoscope” cycle, i.e. 143 successive cycles.

Discussion: Despite the difficulty in cleaning (double sheath), shavers and drill bits used in arthroscopic surgery can be reused without risk since the traces of residual protein are negligible when the instruments are cleaned with a endoscope-quality desinfecting washing machine. In addition, despite intensive use, wear is acceptable for ten cycles. Extensive use of disposable instruments should be carefully debated due to the financial consequences.

Purpose: Study experimental instability by ligament section leaving intact all the periarticular elements.

Material and methods: Sixteen fresh cadaver shoulders were studied. Dissection was achieved via an axillary approach isolating the ligaments without muscle section. Instability was classified in five stages: 0) stable, 1) drawer and sulcus, 2) subluxation: the head crossed the glenoid border but remained in the plane of the glenoid, 3) reversible dislocation: the head was dislocated by returned spontaneously into place when the arm was left to hang along the body, 4) permanent dislocation. The ligaments were sectioned in the following order: 1) betrween 7h and 5h, 2) between 5h and 2h, 3) between 1h and 11h. Instability was tested with usual manœuvres: drawer, sulcus, hyperabduction test, provoked dislocation in elevation and maximal external rotation, downward pressure in the axis of the humerus.

Results: Dissection of the ligaments produced class 1 instability in 0% of the shoulders, Section between 7h and 5h (anterior part of the inferior glenohumeral ligament) yielded class 2 instability in 12 cases, and class 3 instability in six. The hyperabduction test was positive in all shoulders. Section between 5h and 3h (middle glenohumeral ligament) produced class 3 instability in all the shoulders but never permanent dislocation. To obtain class 4 instabilty, section between 1h and 11h (superior glenohumeral ligament) was required. Section of the cuff was not necessary to obtain permanent dislocation.

Discussion: The role of the superior glenohumeral ligament in the production of shoulder instability has not been detailed to date. Closure of the rotator interval, proposed by Nobuhar and by Field, corresponds to retightening this ligament. The function of the superior glenohumeral ligament should be taken into account during the treatment of shoulder instability.