Lieven De Wilde

Functional recovery after a reverse prosthesis for reconstruction of the proximal humerus in tumor surgery

An alternative treatment for primary bone tumors of the proximal humerus was assessed. Four patients, who made full functional recovery after complete resection of the proximal humerus inclusive of the rotator cuff and subsequent reconstruction with a reverse shoulder prosthesis, were examined clinically and radiographically. Distinct medialization of the center of rotation of the glenohumeral joint (28 mm) and elongation of the remaining deltoid muscle (116%) were measured. Increased scapular rotation (118%) was observed. The radiologic results and thoracoscapular rhythm analyses were implemented in a three-dimensional computerized model of the glenohumeral joint. This allowed us to calculate a doubling of the moment of the deltoid abductor muscle in the true scapular plane. After tumor surgery, in which the proximal humerus is resected without reinserting the rotator cuff, full functional recovery of the shoulder can be obtained with a total shoulder prosthesis, medializing the glenohumeral center of rotation and elongating the remaining deltoid muscle. Level of Evidence: Therapeutic study, Level IV (case series-no, or historical control group)

Prosthetic overhang is the most effective way to prevent scapular conflict in a reverse total shoulder prosthesis

Background and purpose Despite good clinical results with the reverse total shoulder arthroplasty, inferior scapular notching remains a concern. We evaluated 6 different solutions to overcome the problem of scapular notching. Methods An average and a “worst case scenario” shape in A-P view in a 2-D computer model of a scapula was created, using data from 200 “normal” scapulae, so that the position of the glenoid and humeral component could be changed as well as design features such as depth of the polyethylene insert, the size of glenosphere, the position of the center of rotation, and downward glenoid inclination. The model calculated the maximum adduction (notch angle) in the scapular plane when the cup of the humeral component was in conflict with the scapula. Results A change in humeral neck shaft inclination from 155° to 145° gave a 10° gain in notch angle. A change in cup depth from 8 mm to 5 mm gave a gain of 12°. With no inferior prosthetic overhang, a lateralization of the center of rotation from 0 mm to 5 mm gained 16°. With an inferior overhang of only 1 mm, no effect of lateralizing the center of rotation was noted. Downward glenoid inclination of 0º to 10º gained 10°. A change in glenosphere radius from 18 mm to 21 mm gained 31° due to the inferior overhang created by the increase in glenosphere. A prosthetic overhang to the bone from 0 mm to 5 mm gained 39°. Interpretation Of all 6 solutions tested, the prosthetic overhang created the biggest gain in notch angle and this should be considered when designing the reverse arthroplasty and defining optimal surgical technique.

Measuring shoulder external and internal rotation strength and range of motion: comprehensive intra-rater and inter-rater reliability study of several testing protocols

BACKGROUND Shoulder range of motion (ROM) and strength measurements are imperative in the clinical assessment of the patients status and progression over time. The method and type of assessment varies among clinicians and institutions. No comprehensive study to date has examined the reliability of a variety of procedures based on different testing equipment and specific patient or shoulder position. The purpose of this study was to establish absolute and relative reliability for several procedures measuring the rotational shoulder ROM and strength into internal (IR) and external (ER) rotation strength. METHODS Thirty healthy individuals (15 male, 15 female), with a mean age of 22.1 ± 1.4 years, were examined by 2 examiners who measured ROM with a goniometer and inclinometer and isometric strength with a hand-held dynamometer (HHD) in different patient and shoulder positions. Relative reliability was determined by intraclass correlation coefficients (ICC). Absolute reliability was quantified by standard error of measurement (SEM) and minimal detectable change (MDC). Systematic differences across trials or between testers, as well as differences among similar measurements under different testing circumstances, were analyzed with dependent t tests or repeated-measures analysis of variance in case of 2 or more than 2 conditions, respectively. RESULTS Reliability was good to excellent for IR and ER ROM and isometric strength measurements, regardless of patient or shoulder position or equipment used (ICC, 0.85-0.99). For some of the measurements, systematic differences were found across trials or between testers. The patients position and the equipment used resulted in different outcome measures. CONCLUSIONS All procedures examined showed acceptable reliability for clinical use. However, patient position and equipment might influence the results.

Omarthrose ecentrée: symposium

Cuff tear arthropathy is defined as the combination of a gleno-humeral arthritis and a massive rotators cuff tear. It is generally admitted that the cuff tear, or its deficiency jeopardises the results of anatomic prosthesis. Grammont imagined and grew the concept of the reverse prosthesis whose aim was to remedy the insufficiency of the rotator cuff and whose use has dramatically modified the therapeutic approach in these complicated situations. The aim of this symposium is to analyse the results of shoulder arthroplasty (anatomic prosthesis, bipolar or reverse) in cuff tear arthropathy, in massive and isolated cuff tears which justify the use of prosthetic surgery, and in centered osteoarthritis with deficient cuff also justifying this use. Massive cuff tears and cuff tear arthropathy have been considered as the stages of a same pathology by Hamada whose classification has been used for the purposes of this study. Out of the 738 initial prosthesis, 111 have been eliminated because of death, incomplete files or lost of sight, without any known complication. Out of the remaining 627 who were used as a basis for this symposium (representing 85% of initial cases), 570 who still had their prosthesis were reviewed and their functional results analysed after 2 years or more. The population was mainly female (72%) who were injured on the dominant side (75%) with a mean age of 72 years. The preoperative Constant score was in average 24 and 24% of the patients had already been operated on their shoulder. For those who had an acetabulization of the acromion, the strength in external rotation was significantly less satisfying and the lesion of the infraspinatus and the teres minor were more frequent. 48 hemiarthroplasties, 52 bipolar and 527 reverse prosthesis were studied. At revision, with an average follow up of 52 months, the revision rate was 23% for hemiarthroplasties, 14% for reversed prosthesis and only 8% for bipolar prosthesis. The prosthesis was removed in 21% of hemiarthroplasties, 5% of reverse and 2% of bipolar. No infection to report in the hemi group or the bipolar group, whereas there was an infection rate of 5% in the reverse group. Nevertheless, the Constant score was significantly better with reverse (62) than with bipolar (45) or hemi (44). The active elevation was also better with the reverse whereas the external rotation was not as good as with anatomic prosthesis. The analytic study of the results of the reverse prosthesis shows a negative influence of the lesion of the sub-scapularis and the teres minor. The results are disappointing with young patients and those who had surgical precedents. On X-ray, we can notice 0.5% of humeral loosening withouth any correlation to the fact that the implant is cemented or not, 3.6% of glenoid loosening and 68% of scapular notches without any significant change on the Constant score. Their occurrence is correlated to a preoperative rising of the humeral head and a superior glenoid lesion. It is observed more frequently with the supero-lateral approach compared to the delto-pectoral one. The frequency of these notches grows with the follow up and their occurrence is often associated to humeral radiolucent lines. On the long term, the survival rate of these prosthesis is 89% at 10 years. The Constant score deteriorates gradually after 7 years; this seems to be linked to the occurrence of x-ray modifications in the years that followed. The main complications observed with reverse prosthesis were the infections (5.1%), the glenoid problems (5.1%), the instabilities (3.6%), the acromion fractures (3.0%). Infections can be treated by a wash out and antibiotics in the first 3 months, then the removal of the prosthesis becomes necessary. The instabilities occur more often for males, with delto-pectoral approach and with 36mm diameter glenoids. The glenoid problems are frequent in the first years and often due to technical errors or material defects (unscrewing of the glenosphere). Acromion fractures have an important clinical impact when they concern the spine and there healing is difficult to obtain, whichever method is used. In conclusion, the use of a prosthesis for cuff tear arthropathies must be thought about, especially in massive cuff tear without osteoarthritis, in patients with previous surgery, and in patients younger than 70. If the active elevation is conserved and the patient is young, the use of an hemi or a bipolar prosthesis can be debated. In other cases, the indication of a reverse prosthesis is preferable given that the clinical results are better. In these cases, the surgical technique must be accurate, bearing in mind the advantages and disadvantages of the two possible approaches, the type of implant (36 vs 42), the position and orientation of the glenoid baseplate according to the pre-operative bone wear, the orientation of the humeral implant, the need for reinsertion of the subscapularis and, maybe, the possibility of an associated transfer of the latissimus dorsi.Cuff tear arthropathy is defined as the combination of a gleno-humeral arthritis and a massive rotators cuff tear. It is generally admitted that the cuff tear, or its deficiency jeopardises the results of anatomic prosthesis. Grammont imagined and grew the concept of the reverse prosthesis whose aim was to remedy the insufficiency of the rotator cuff and whose use has dramatically modified the therapeutic approach in these complicated situations. The aim of this symposium is to analyse the results of shoulder arthroplasty (anatomic prosthesis, bipolar or reverse) in cuff tear arthropathy, in massive and isolated cuff tears which justify the use of prosthetic surgery, and in centered osteoarthritis with deficient cuff also justifying this use. Massive cuff tears and cuff tear arthropathy have been considered as the stages of a same pathology by Hamada whose classification has been used for the purposes of this study. Out of the 738 initial prosthesis, 111 have been eliminated because of death, incomplete files or lost of sight, without any known complication. Out of the remaining 627 who were used as a basis for this symposium (representing 85% of initial cases), 570 who still had their prosthesis were reviewed and their functional results analysed after 2 years or more. The population was mainly female (72%) who were injured on the dominant side (75%) with a mean age of 72 years. The preoperative Constant score was in average 24 and 24% of the patients had already been operated on their shoulder. For those who had an acetabulization of the acromion, the strength in external rotation was significantly less satisfying and the lesion of the infraspinatus and the teres minor were more frequent. 48 hemiarthroplasties, 52 bipolar and 527 reverse prosthesis were studied. At revision, with an average follow up of 52 months, the revision rate was 23% for hemiarthroplasties, 14% for reversed prosthesis and only 8% for bipolar prosthesis. The prosthesis was removed in 21% of hemiarthroplasties, 5% of reverse and 2% of bipolar. No infection to report in the hemi group or the bipolar group, whereas there was an infection rate of 5% in the reverse group. Nevertheless, the Constant score was significantly better with reverse (62) than with bipolar (45) or hemi (44). The active elevation was also better with the reverse whereas the external rotation was not as good as with anatomic prosthesis. The analytic study of the results of the reverse prosthesis shows a negative influence of the lesion of the sub-scapularis and the teres minor. The results are disappointing with young patients and those who had surgical precedents. On X-ray, we can notice 0.5% of humeral loosening withouth any correlation to the fact that the implant is cemented or not, 3.6% of glenoid loosening and 68% of scapular notches without any significant change on the Constant score. Their occurrence is correlated to a preoperative rising of the humeral head and a superior glenoid lesion. It is observed more frequently with the supero-lateral approach compared to the delto-pectoral one. The frequency of these notches grows with the follow up and their occurrence is often associated to humeral radiolucent lines. On the long term, the survival rate of these prosthesis is 89% at 10 years. The Constant score deteriorates gradually after 7 years; this seems to be linked to the occurrence of x-ray modifications in the years that followed. The main complications observed with reverse prosthesis were the infections (5.1%), the glenoid problems (5.1%), the instabilities (3.6%), the acromion fractures (3.0%). Infections can be treated by a wash out and antibiotics in the first 3 months, then the removal of the prosthesis becomes necessary. The instabilities occur more often for males, with delto-pectoral approach and with 36mm diameter glenoids. The glenoid problems are frequent in the first years and often due to technical errors or material defects (unscrewing of the glenosphere). Acromion fractures have an important clinical impact when they concern the spine and there healing is difficult to obtain, whichever method is used. In conclusion, the use of a prosthesis for cuff tear arthropathies must be thought about, especially in massive cuff tear without osteoarthritis, in patients with previous surgery, and in patients younger than 70. If the active elevation is conserved and the patient is young, the use of an hemi or a bipolar prosthesis can be debated. In other cases, the indication of a reverse prosthesis is preferable given that the clinical results are better. In these cases, the surgical technique must be accurate, bearing in mind the advantages and disadvantages of the two possible approaches, the type of implant (36 vs 42), the position and orientation of the glenoid baseplate according to the pre-operative bone wear, the orientation of the humeral implant, the need for reinsertion of the subscapularis and, maybe, the possibility of an associated transfer of the latissimus dorsi.

Cerebral oxygen desaturation during beach chair position

Context Cases of ischaemic brain damage have been reported in relatively healthy patients undergoing shoulder surgery in the beach chair position. Unrecognised cerebral hypoperfusion may have contributed to these catastrophic events, indicating that routine anaesthesia monitoring may not suffice. Near-infrared spectroscopy (NIRS) provides a non-invasive, continuous method to measure regional cerebral oxygen saturation (rScO2). Objectives The aim of this clinical investigation was to evaluate the prevalence of regional cerebral oxygen desaturation in patients undergoing shoulder surgery in the upright position during routine anaesthesia management. We also aimed to identify some causal factors for cerebral desaturation. Design Prospective, observational, blinded study. Setting University hospital. Observation period from 19 05 2008 to 26 08 2008. Patients Twenty consecutive adult patients presenting for elective shoulder surgery under general anaesthesia in the beach chair position were enrolled. Patients with clinically apparent neurological or cognitive dysfunction were excluded. Interventions Routine anaesthesia management and standard monitoring were used. The responsible anaesthesiologist was blinded to the rScO2 data and was not informed about the purpose of the study. Main outcome measures The prevalence of cerebral oxygen desaturation was measured. Results With beach chair positioning, rScO2 decreased significantly from 79 ± 9 to 57 ± 9% on the left side and from 77 ± 10 to 59 ± 10% on the right side (P < 0.001). A relative decrease in rScO2 of more than 20% occurred in 80% of patients when the beach chair position was adopted. Postural decreases in cerebral oxygenation were related to blood pressure (r = 0.60, P = 0.007) and end-tidal carbon dioxide concentration (r = 0.47, P = 0.035). Conclusion The high prevalence of significant cerebral oxygen desaturation during shoulder surgery in the upright position underlines the need for close monitoring. NIRS might constitute a valuable technique to detect cerebral hypoperfusion in this high-risk group of patients.

Glenohumeral relationship in the transverse plane of the body

Reconstruction of a normal glenohumeral relationship is desirable for a successful arthroplasty. Double-contrast computed tomography was performed on 49 healthy shoulders in young volunteers. For creation of a uniform spatial reference system, the subjects were positioned in a thoracobrachial orthosis with the arm adducted in the coronal plane and the forearm flexed in the sagittal plane, and they were examined in dorsal recumbency. The classical anatomic angles were measured, and the anatomic axes were determined and quantified as angles to the coronal plane. When the axis of the glenoid was correlated to the axis of the humeral head, a mean of 8.5 degrees divergence in a clear Gaussian distribution was found. This contrasts with the variability of the version of the humeral head and of the glenoid and offers a useful guideline in difficult prosthetic surgery of the shoulder in which normal anatomic landmarks are lost because of arthritic or traumatic deformity.

Consequences of Scapular Anatomy for Reversed Total Shoulder Arthroplasty

The reverse total shoulder prosthesis provides successful functional outcome in many patients with rotator cuff tear arthropathy. However, scapular notching, a direct consequence of mechanical impingement between the humeral prosthesis and the glenoid, remains a major concern. We presumed a better knowledge of the anatomy of the scapula would enable design or placement modifications to minimize this phenomenon. After establishing a uniform spatial reference system using easy locatable surgical reference points and planes, we analyzed 200 dry bony scapulae and defined the glenoid and infraglenoid anatomy relative to the reference system. The bony rim of the two inferior quadrants of the glenoid forms a semicircle the center of which can be used perioperatively as an easy locatable bony reference point. The infraglenoid tubercle varies in width and length, and can interfere with the humeral part of the reverse prosthesis, creating scapular notching. To avoid notching, we suggest using a convex base plate with a smaller radius than currently used, placing it as low as possible with a 42-mm glenosphere eccentrically assembled to create a posterior offset. If prosthetic overhang cannot be obtained, we suggest removing part of the infraglenoid tubercle.

Reliability of the glenoid plane

HYPOTHESIS The purpose of this study was to investigate the 3-dimensional (3-D) orientation of the glenoid and scapular planes. Different definitions of the glenoid plane were used and different planes measured, and we hypothesed that the 3-D plane with the least variation would be best to define the most reliable glenoid plane. METHODS We studied 150 CT scans from nonpathological shoulders from patients between 18 and 80. The scapular plane and 5 different glenoid planes were determined: inferior, anterior, posterior, superior, and neutral. All plane versions and inclination angles were measured. Because all examinations were done in a standardized position to the coronal, sagittal, and transverse planes of the body, the scapular plane could be defined versus the coronal, sagittal, and transverse planes of the body. RESULTS The version (mean, 3.76) of the inferior glenoid plane showed a significantly lower standard deviation than the version of the anterior (P < .001), posterior (P=.001), and superior (P=.001) glenoid plane (ANOVA). For inclination all planes have a similar variance. The scapular plane was different between gender (P=.022) and correlated with age. CONCLUSION This study showed that the retroversion of the inferior glenoid is reasonably constant. The osseous anthropometry of the inferior glenoid can offer a reproducible point of reference to be used in prosthetic surgery of the shoulder.

Erratum: Glenosphere Disengagement: A Potentially Serious Default in Reverse Shoulder Surgery

Implant failure is a serious complication in reverse shoulder arthroplasty. We determined the incidence of glenosphere disengagement in a cohort of 479 reverse shoulder prostheses (468 Delta III TM (DePuy International Ltd, Leeds, UK), 11 Aequalis TM (Tornier, Grenoble, France)). We also determined whether disengagement adversely affected clinical outcomes. The minimum followup was 12 months (mean, 28.6 months; range, 12-72 months). Disengagement of the glenosphere occur- red in 16 of 479 shoulders (3.2%). In 13 patients, the disengagement was partial (clear step-off between the baseplate and the glenosphere) and was not associated with a poor functional outcome with this short-term followup. In three patients, the disengagement led to a fracture of the central screw, leading to a complete disengagement of the glenosphere from the baseplate, necessitating revision in two; the third refused revision. Partial disengagement was seen in five of 11 Aequalis TM prostheses (45.4%) and eight of 468 Delta III TM prostheses (1.7%). The three total dis- engagements with central screw breakage all occurred in Delta III TM prostheses. We believe differences in the type of locking screws may explain the differences observed between the two types of reverse prostheses. Level of Evidence: Level III, retrospective study. See the Guidelines for Authors for a complete description of levels of evidence.

Prosthetic component relationship of the reverse Delta III total shoulder prosthesis in the transverse plane of the body

The Delta III (DePuy International Ltd, Leeds, UK) reverse total shoulder prosthesis has provided a successful functional outcome in cuff tear arthropathy (CTA); however, internal and external rotation remain compromised. Positioning of the prosthetic components in the transverse plane has theoretically been suggested to affect rotation. Twenty-seven patients who received a Delta III reversed total shoulder prosthesis for CTA were analyzed (mean follow-up, 43 months) using standard radiographs and computed tomography. The position of the prosthetic components and the possible influence of scapular rotation was analyzed using a uniform spatial reference system using axes in reference to the sagittal or coronal plane. We assessed impingement of the humeral component on the glenoid neck in neutral and internal rotation. An increase in the anterior divergence of the glenoid and humeral prosthetic components correlates with an increase in radiologically measured internal rotation (r = 0.932, P < .001). The uniformity of the reference system used seems to allow accurate positioning of the components intraoperatively and can be useful for analysis of the prosthetic component relationship postoperatively.