Bernard Augereau

A 4-portal arthroscopic stabilization in posterior shoulder instability.

The purpose of this study was to present an arthroscopic stabilization technique with 4 portals for posterior instability used in 11 patients (13 shoulders). There were 7 male and 4 female patients. All patients had an arthroscopic labral suture with anchors and capsular plication with 4 portals. The follow-up period averaged 34 months. No complication or recurrence of instability was noted. A moderate loss of range of motion was noted in 4 shoulders and moderate pain in 2 shoulders. All patients were satisfied. According to the literature, the rate of recurrence of instability is currently lower than 12% when a labral suture and capsular plication are performed. Our results for pain and range of motion are similar to those described in recent publications. However, we think that the 4-portal technique allows a facilitated access to the posteroinferior part of the glenoid and reduces the rate of postoperative instability.

Glenoid Loosening after Total Shoulder Arthroplasty: An In Vitro CT-Scan Study

Glenoid fixation failure has only been grossly characterized. This lack of information hinders attempts to improve fixation because of a lack of methodologies for detecting and monitoring fixation failure. Our goal was twofold: to collect detailed data of glenoid fixation fracture, and to investigate computed tomography (CT)‐scanning as a tool for investigations of fixation failure. Six cadaver scapulas and six bone‐substitute specimens were cyclically loaded and CT‐scanned at clinical settings after 0, 1,000, 5,000, 10,000, 30,000, 50,000 and 70,000 load cycles. The fixation status was evaluated by inspection of the scans. After 70,000 cycles, the specimens were sectioned, and the fixation inspected by microscopy. The results of the microscopy analysis were compared to the CT‐scan analysis. Fracture of the glenoid fixation initiated at the edge of the glenoid rim and propagated towards and around the keel of the implant. The entire process from initiation to complete fracture took place at the polyethylene implant–cement interface, while the cement, the adjacent bone, and the cement–bone interface remained intact. Thus, strengthening the polyethylene–cement interface should improve glenoid fixation. Microscopy results validated the CT methodology, suggesting that the CT technique is reliable.

Accuracy of Glenoid Component Placement in Total Shoulder Arthroplasty and Its Effect on Clinical and Radiological Outcome in a Retrospective, Longitudinal, Monocentric Open Study

Background The success of Total Shoulder Arthroplasty (TSA) is believed to depend on the restoration of the natural anatomy of the joint and a key development has been the introduction of modular humeral components to more accurately restore the patient’s anatomy. However, there are no peer-reviewed studies that have reported the degree of glenoid component mal-position achieved in clinical practice and the clinical outcome of such mal-position. The main purpose of this study was to assess the accuracy of glenoid implant positioning during TSA and to relate it to the radiological (occurrence of radiolucent lines and osteolysis on CT) and clinical outcomes. Methods 68 TSAs were assessed with a mean follow-up of 38+/−27 months. The clinical evaluation consisted of measuring the mobility as well as of the Constant Score. The radiological evaluation was performed on CT-scans in which metal artefacts had been eliminated. From the CT-scans radiolucent lines and osteolysis were assessed. The positions of the glenoid and humeral components were also measured from the CT scans. Results Four position glenoid component parameters were calculated The posterior version (6°±12°; mean ± SD), the superior tilt (12°±17°), the rotation of the implant relative to the scapular plane (3°±14°) and the off-set distance of the centre of the glenoid implant from the scapular plane (6±4 mm). An inferiorly inclined implant was found to be associated with higher levels of radiolucent lines while retroversion and non-neutral rotation were associated with a reduced range of motion. Conclusion this study demonstrates that glenoid implants of anatomic TSA are poorly positioned and that this malposition has a direct effect on the clinical and radiological outcome. Thus, further developments in glenoid implantation techniques are required to enable the surgeon to achieve a desired implant position and outcome.

Developments in shoulder arthroplasty

Abstract Indications for shoulder arthroplasty are numerous, mainly owing to glenohumeral osteoarthritis, rheumatoid arthritis, or fracture of the proximal humerus. However, the anatomy and the biomechanics of the shoulder are complex and shoulder arthroplasty has evolved significantly over the past 30 years. This paper presents the main recent evolutions in shoulder replacement, the questions not answered yet, and the main future areas of research. The review focuses firstly on the design, positioning, and fixation of the humeral component, secondly on the design, positioning, and fixation of the glenoid implant, and thirdly on other concepts of shoulder arthroplasty such as the reversed prosthesis, the cementless surface replacement arthroplasty, and the bipolar arthroplasty. This review demonstrates that more research is needed. Although, in the long term, large randomized trials are needed to settle the fundamental questions of what type of replacement and which kind of fixation should be used, biomechanical research in the laboratory should be focused primarily on the comprehension of glenoid loosening, which is a major cause of total shoulder arthroplasty failure, and the significance of radiolucent lines which are often seen but with no clear understanding about their relation with failure.

Arthroplastie de hanche à couple métal-métal sur polyéthylène cimenté: Résultats à moyen terme

PURPOSE OF THE STUDY Metal-on-metal bearings in total hip arthroplasty may, in theory, provide an effective answer to osteolysis in active patients. The purpose of this retrospective study was to evaluate the results of a consecutive series of Metasul total hip arthroplasties with a cemented socket. MATERIAL AND METHODS The series was composed of 28 total hip arthroplasties in 23 patients (13 women and 10 men). The mean age at operation was 44 +/- 8.3 years (range 22-59 years). The initial diagnosis was osteoarthritis (14 hips), osteonecrosis of the femoral head (11 hips) and rheumatoid arthritis (3 hips). Cemented cups with a metal articulation surface molded into the polyethylene were used. The cup was articulated with a 28-mm metallic head. Cemented stems were used in 27 hips, whereas a hydroxyapatite coated stem was implanted in one hip. RESULTS One hip required revision for deep infection five months postoperatively. One patient (one hip) was lost to follow-up. Twenty-six hips were evaluated at an average 31-month follow-up (range 12-47 months). All hips were rated excellent or very good. Radiographically, seven hips (27%) had a progressive acetabular radiolucent line, including three complete radiolucent lines. The latter always were located at the bone-cement interface. No implant migration was noted. In these cases, the mean socket diameter was lower than for the rest of the cohort (p < 0.001). DISCUSSION AND CONCLUSION Progression of acetabular radiolucent lines remains of concern in this series of Metasul artificial hips. It is hypothesized that the diminution of polyethylene thickness has led to an increased rigidity of the socket, resulting in a higher rate of constraints at the bone-cement interface. Special attention must be given to these hips.

Surgical treatment of three and four-part proximal humeral fractures

Three- and four-part fractures of the proximal humerus are usually treated surgically. Open reduction with internal fixation (ORIF) is the method of choice in younger patients. Anatomic reduction of the tuberosities is crucial to ensure that, in the event of poorly tolerated avascular necrosis of the humeral head, hemiarthroplasty can be performed under optimal conditions. Suboptimal outcomes may occur after ORIF, as less-than-perfect reduction and fixation is poorly tolerated at the shoulder. Preoperative computed tomography must be performed routinely to analyse fragment displacement and comminution, classify the fracture, assess humeral head vitality, and evaluate the mechanical properties of the underlying bone. Fracture reduction relies on principles that are shared by the various available techniques. Reduction of each fragment should be assessed separately. Reduction of the humeral head to the shaft should be performed before reduction of the tuberosities. The fixation technique should ensure stability of the anatomic reduction, with secure fixation of the tuberosities and a minimal risk of material migration into the joint. Here, we provide a detailed discussion of the various techniques, with their advantages and drawbacks, to help surgeons select the method that is most appropriate to each individual patient.

Do Dual-Mobility Cups Reduce the Risk of Dislocation in Total Hip Arthroplasty for Fractured Neck of Femur in Patients Aged Older Than 75 Years?

BACKGROUND Total hip arthroplasty (THA) for intracapsular neck of femur (NOF) fracture remains debatable as it is associated with higher rates of dislocation, notably in the older part of the population. We hypothesized this risk could be limited using dual-mobility cups (DMCs). METHODS Eighty-two patients (83 hips) aged older than 75 years underwent DMC-THA using a posterolateral approach for an intracapsular NOF fracture. RESULTS Clinical data were collected in 45 patients at a mean of 23.8 ± 9.4 months (12.1-42 months). The mortality rates were 19% (16 patients) and 36.5% (30 patients) at 1 year postoperatively and at the last follow-up, respectively. Postoperatively, there were 2 dislocations of the large articulation (4.4%) and one intraprosthetic dislocation (2.2%), all related to technical errors. Functional results were rated at least good in 71% cases, whereas the Parker and Devane scores were stable, indicating optimal restoration of autonomy and physical activity. CONCLUSION Although technically demanding, DMC-THA may prevent dislocation in intracapsular NOF fracture in elderly patients, while consistently limiting the risk of loss of independence.

Total shoulder arthroplasty does not correct the orientation of the eroded glenoid

Background and purpose Alignment of the glenoid component with the scapula during total shoulder arthroplasty (TSA) is challenging due to glenoid erosion and lack of both bone stock and guiding landmarks. We determined the extent to which the implant position is governed by the preoperative erosion of the glenoid. Also, we investigated whether excessive erosion of the glenoid is associated with perforation of the glenoid vault. Methods We used preoperative and postoperative CT scans of 29 TSAs to assess version, inclination, rotation, and offset of the glenoid relative to the scapula plane. The position of the implant keel within the glenoid vault was classified into three types: centrally positioned, component touching vault cortex, and perforation of the cortex. Results Preoperative glenoid erosion was statistically significantly linked to the postoperative placement of the implant regarding all position parameters. Retroversion of the eroded glenoid was on average 10° (SD10) and retroversion of the implant after surgery was 7° (SD11). The implant keel was centered within the vault in 7 of 29 patients and the glenoid vault was perforated in 5 patients. Anterior cortex perforation was most frequent and was associated with severe preoperative posterior erosion, causing implant retroversion. Interpretation The position of the glenoid component reflected the preoperative erosion and “correction” was not a characteristic of the reconstructive surgery. Severe erosion appears to be linked to vault perforation. If malalignment and perforation are associated with loosening, our results suggest reorientation of the implant relative to the eroded surface.

Measurement of femoral head penetration in polyethylene using a 3-dimensional CT-scan technique

Background Current techniques for measuring in vivo polyethylene wear suffer from a range of problems, resulting in an unacceptable lack of repeatability and/or insufficient accuracy when they are used to measure the low wear rates associated with new, highly crosslinked polyethylene. We describe an improved CT method for measurement of 3D femoral head penetration in PE acetabular cups that has sufficient accuracy and repeatability to allow assessment of the wear potential of modern implants. Method The accuracy and repeatability of the CT-scan method was determined by blindly repeating measurements on a precisely calibrated 28-mm prosthetic head and by comparing them with direct metrological measurements on 10 acetabular specimens with in vitro wear from machining, and on 8 explanted acetabular specimens with in vivo wear. Results The intra- and interobserver errors in femoral head diameter were 0.036 mm (SD 0.044) and 0.050 mm (SD 0.022), respectively. CT estimated femoral head penetration in both all-poly and metal-backed acetabular components with accuracy ranging from 0.009 to 0.245 mm (mean 0.080; SD 0.067). Interpretation We found that the CT method is rapid, is accurate, and has repeatability and ease of availability. Using a slice thickness of 0.0625 mm, this method can detect wear—and also the threshold for the wear rate that causes osteolysis—much earlier than previous methods.

A CT scan protocol for the detection of radiographic loosening of the glenoid component after total shoulder arthroplasty

Background and purpose It is difficult to evaluate glenoid component periprosthetic radiolucencies in total shoulder arthroplasties (TSAs) using plain radiographs. This study was performed to evaluate whether computed tomography (CT) using a specific patient position in the CT scanner provides a better method for assessing radiolucencies in TSA. Methods Following TSA, 11 patients were CT scanned in a lateral decubitus position with maximum forward flexion, which aligns the glenoid orientation with the axis of the CT scanner. Follow-up CT scanning is part of our routine patient care. Glenoid component periprosthetic lucency was assessed according to the Molé score and it was compared to routine plain radiographs by 5 observers. Results The protocol almost completely eliminated metal artifacts in the CT images and allowed accurate assessment of periprosthetic lucency of the glenoid fixation. Positioning of the patient within the CT scanner as described was possible for all 11 patients. A radiolucent line was identified in 54 of the 55 observed CT scans and osteolysis was identified in 25 observations. The average radiolucent line Molé score was 3.4 (SD 2.7) points with plain radiographs and 9.5 (SD 0.8) points with CT scans (p = 0.001). The mean intra-observer variance was lower in the CT scan group than in the plain radiograph group (p = 0.001). Interpretation The CT scan protocol we used is of clinical value in routine assessment of glenoid periprosthetic lucency after TSA. The technique improves the ability to detect and monitor radiolucent lines and, therefore, possibly implant loosening also.