Long-term impact of scapular notching after reverse shoulder arthroplasty.

BACKGROUND: Because it medializes the centre of rotation, one of the drawbacks of reverse shoulder arthroplasty (RSA) is the risk of impingement between the humerus and lateral border of the scapula resulting in scapular notching. The long-term impact of this notching is not well known, either on function or the risk of glenoid loosening. The aim of this longitudinal study was to analyze the drawbacks of this notching. METHODS: Between 1993 and 2006, 81 patients (91 shoulders) underwent RSA for primary glenohumeral osteoarthritis or massive cuff tear with or without osteoarthritis. This cohort was followed longitudinally with post-operative assessments done at one to two  years (T1), three to eight  years (T2), and nine+ years (T3). Before T3, 25 patients had died, nine were lost to follow-up, five  had the implants changed, and seven  had incomplete records. Thus, 45 shoulders were available for follow-up beyond nine years (mean follow-up of 12 years) and were used to determine the long-term impact of notching. Survival curves were generated using the occurrence of Sirveaux grade 3 or 4 notching and the presence of aseptic glenoid loosening as endpoints. RESULTS: The survivorship before grade 3 or 4 notching developed was 83% at five years, 60% at 10 years, and 43% at 15 years. In the end, aseptic glenoid loosening occurred in four shoulders, all of which had developed grade 4 notching. No glenoid loosening occurred in the population with grade 0, 1, 2, or 3 notching (p = 0.02). The Constant score significantly decreased between T2 and T3, although it was not different between shoulders with and without advanced notching. CONCLUSIONS: Beyond the second year post-RSA, the number of shoulders with grade 3 or 4 notching increases steadily up to the longest follow-up. Grade 4 notching always preceded the occurrence of late glenoid loosening. The functional outcomes become significantly worse after the 9th year post-RSA, although they were not correlated to the presence of high-grade scapular notching.

Superior glenoid inclination and glenoid bone loss : Definition, assessment, biomechanical consequences, and surgical options.

Correct anatomical alignment of the glenoid component is of central importance for wear and loosening in shoulder endoprostheses. The aim of this article is to review and clarify the biomechanical and clinical effects of incorrect glenoid inclination in reverse and anatomical joint replacements. Based on the literature and on our own work, statements are made about the following: (1) the glenoid inclination of a normal glenoid, a degenerative glenoid and a glenoid implant, and the consequences if superior inclination is too large, and (2) the surgical technique as well as tips and tricks for correct adjustment of the inclination. The inclination of the glenoid plane is a morphological parameter of the scapula with high individual variation and is best measured using reformatted computed tomography using three-dimensional software for reconstruction and evaluation. The standard value is between 0 and 10°. Excessive superior inclination promotes translation of the humeral head and the formation of rotator cuff tears-in a degenerative glenoid, to superior wear. The correct amount of superior inclination of the glenoid component is essential for the survival of the implant. Positioning without excessive superior inclination is therefore mandatory. Precise preoperative determination of glenoid inclination and wear is important in order to correctly plan the positioning of an implant. This serves as the basis for deciding whether a bone graft or patient-specific instrumentation is necessary. Thus, the surgeon also has prognostic parameters for the anticipation of possible complications as a result of the bone defect and abnormal orientation. However, the evaluation must always include the position of the scapula in these considerations.

Shoulder patient-specific guide: First experience in 10 patients indicates room for improvement.

BACKGROUND: Implantation of the glenoid component of a total shoulder prosthesis can be facilitated by using a patient-specific guide (PSG) designed to ensure replication of the preoperatively planned position. The objective of this study was to assess the reliability and accuracy of a PSG in replicating the planned glenoid component position during total shoulder arthroplasty (TSA). HYPOTHESIS: Additional criteria should be used for 3D preoperative planning and PSG design to further improve the accuracy of glenoid component positioning. MATERIAL AND METHODS: We studied 10 patients who underwent TSA with use of a PSG to position the glenoid component after preoperative 3D planning. Postoperative glenoid version and tilt were measured and compared to the planned values. We also used new criteria to assess implant rotation and global 3D position, as well as accuracy of the 3D pilot hole for the glenoid guide-pin. RESULTS: Mean errors in glenoid position were -1.7°±4.4° for version, -0.4°±4.9° for tilt, and 6.0°±13.5° for rotation. Mean difference in global orientation of the glenoid implant versus the planned value was 4.9°±2.5°. Mean 3D discrepancy in glenoid pilot hole position was 2.9±0.5mm; the discrepancy was greater in the mediolateral direction (1.9±0.9mm) than in the supero-inferior (1.1±1.2mm) and antero-posterior (0.8±1.2mm) directions. DISCUSSION: The poor performance of the PSG in controlling rotation and reaming may explain the difference in global glenoid position compared to the planned value. Improvements in PSG design to incorporate these two parameters deserve consideration. LEVEL OF EVIDENCE: II, prospective cohort study.

Preoperative planning for accurate glenoid component positioning in reverse shoulder arthroplasty.

BACKGROUND: Glenoid component positioning in reverse shoulder arthroplasty (RSA) is challenging. Patient-specific instrumentation (PSI) has been advocated to improve accuracy, and is based on precise preoperative planning. The purpose of this study was to determine the accuracy of glenoid component positioning when only the glenoid surface is visible, compared to when the entire scapula is visible on a 3D virtual model. METHODS: CT scans of 30 arthritic shoulders were reconstructed in 3D models. Two surgeons then virtually placed a glenosphere component in the model while visualizing only the glenoid surface, in order to simulate typical intraoperative exposure ("blind 3D" surgery). One surgeon then placed the component in an ideal position while visualizing the entire scapula ("visible 3D" surgery). These two positions were then compared, and the accuracy of glenoid component positioning was assessed in terms of correction of native glenoid version and tilt, and avoidance of glenoid vault perforation. RESULTS: Mean version and tilt after "blind 3D" surgery were +1.4° (SD 8.8°) and +7.6° (SD 6°), respectively; glenoid vault perforation occurred in 17 specimens. Mean version and tilt after "visible 3D" surgery were +0.3° (SD 0.8°) and +0.1° (SD 0.5°), respectively, with glenoid vault perforation in 6 cases. "Visible 3D" surgery provided significantly better accuracy than "blind 3D" surgery (P<0.05). CONCLUSION: When the entire scapula is used as reference, accuracy is improved and glenoid vault perforation is less frequent. This type of visualization is only possible with pre-operative 3D CT planning, and may be augmented by PSI. LEVEL OF EVIDENCE: Basic science study. Level III.

Efficiency of locking-plate fixation in isolated talonavicular fusion.

INTRODUCTION: Talonavicular (TN) fusion is an effective means of treating hindfoot deformity and pain. At the cost of a certain limited morbidity, it allows lasting stabilization of all of the torque joints. Non-union rates, however, are high, due to insufficient mechanical stability of the fixation. The present study assessed radiological and clinical results in TN fusion fixed by two retrograde compression screws and a dorsal locking plate. MATERIAL AND METHOD: A retrospective single-surgeon study recruited 26 TN fusions performed in 25 patients (13 male, 12 female; mean age, 54.6±15.4years) between March 1st, 2010 and February 28th, 2014. Mean follow-up was 14.9±8.7months. Bone fusion and anatomic results were assessed on dorsoplantar, lateral and Méary weight-bearing radiographs. RESULTS: Radiologic fusion was achieved in all cases, at a mean 2.7±0.7months. Mean TN coverage angle was 21.7±10.5° preoperatively and 3.8±1.8° at follow-up. Mean AOFAS score improved significantly, from 37.2±11.8 (range, 20-53) preoperatively to 79.4±11.4 (range, 45-98) at follow-up. CONCLUSION: TN fusion fixed by two retrograde compression screws and a dorsal locking plate provided a high rate of consolidation without loss of angular correction and with satisfactory clinical results. LEVEL OF EVIDENCE: IV. TYPE OF STUDY: Retrospective.

Dual mobility cup in revision total hip arthroplasty: dislocation rate and survival after 5 years.

BACKGROUND: Dislocation is a common complication of total hip arthroplasty (THA), particularly when performed as revision surgery. Dual mobility cups (DMCs) minimize the risk of instability when implanted during primary THA. However, their usefulness and survival in revision THA remain unclear. We therefore conducted a retrospective study to assess DMC stability and survival at a minimal follow-up period of 5years after revision THA. HYPOTHESIS: The dislocation rate associated with DMCs for revision THA is similar to that seen after primary THA. MATERIALS AND METHODS: Cup exchange with implantation of a DMC was performed in 71 patients (74 hips) between 2000 and 2007, for the following reasons: recurrent dislocation (n=22), aseptic loosening (n=38), and infection (n=14). The DMCs were cemented in 47 cases and cementless in 27 cases. The clinical variables (Merle d'Aubigné-Postel score and Harris Hip Score) and radiological findings were collected retrospectively from the medical records and compared with those obtained at the last follow-up visit. RESULTS: Of the 74 cases, 2 were lost to follow-up. At last follow-up, the mean Merle d'Aubigné-Postel score was 15.2 (11-18) and the mean Harris Hip Score was 80.4 (51-98). Of the 8 failures, 2 (2/72, 2.7%) were related to mechanical factors (1 case each of aseptic loosening and dislocation) and 6 were changed because of infection (recurrent infection, n=4). Mechanical failure was not linked to a specific reason for revision THA. A radiolucent line was visible in 4 cases but this finding was not associated with clinical manifestations. When failure was defined as cup revision for any non-infectious complication, 5-year implant survival was 99% (95% confidence interval, 93-100%). DISCUSSION: Use of a DMC in revision THA was associated with a slightly higher dislocation rate (1/72, 1.4%) than in primary THA, whereas 5-year survival was comparable. Cemented DMCs were not associated with a greater risk of loosening. CONCLUSION: DMCs are useful to decrease the risk of dislocation in revision THA performed for any reason. The low rate of loosening indicates that DMCs do not result in high stresses at the bone-implant interface. LEVEL OF EVIDENCE: IV, retrospective study.

Effect of scapular pillar anatomy on scapular impingement in adduction and rotation after reverse shoulder arthroplasty.

BACKGROUND: Notching of the scapular pillar is the main radiographic complication seen during follow-up of reverse shoulder arthroplasties. Several recommendations pertaining to the implantation technique and glenoid component design have been suggested. No studies have investigated potential anatomic risk factors for inferior scapular impingement. HYPOTHESIS: A specific anatomic shape of the scapular pillar promotes the development of notching. MATERIALS AND METHODS: The Aequalis Reversed(®) (Tornier Inc., Edina, MN, USA) prosthesis was implanted into 40 cadaver scapulae. We measured maximal range-of-motion (ROM) in internal rotation, external rotation, and adduction. The anatomic specimens were then imaged using two-dimensional computed tomography (CT) and the scapular neck angle, surface area under the scapular pillar, and distance from the central glenosphere peg to the inferior glenoid rim were measured. Associations between these CT parameters and ROM values were assessed using statistical independence tests. RESULTS: ROM values were greatest when the surface area under the scapular pillar was above 0.8 cm(2) (P<0.5). This feature combined with a scapular neck angle less than 105° produced the largest ROM values (P<0.5). DISCUSSION: The scapular neck angle alone is not sufficient to identify a scapular morphology that increases the risk of notching. The surface area under the scapular pillar, in contrast, discriminates between scapulae with and without a high risk of notching. The surface area under the scapular pillar is influenced by the inferior glenoid offset. CONCLUSION: We were unable to define a specific scapular shape at high risk for notching. The prevention of notching should rely chiefly on a rigorous glenoid component implantation technique, with particular attention to the inferior offset. LEVEL OF EVIDENCE: III, experimental study.

Influence of glenoid component design and humeral component retroversion on internal and external rotation in reverse shoulder arthroplasty: a cadaver study.

BACKGROUND: A common disadvantage of reverse shoulder arthroplasty is limitation of the range of arm rotation. Several changes to the prosthesis design and implantation technique have been suggested to improve rotation range of motion (ROM). HYPOTHESIS: Glenoid component design and degree of humeral component retroversion influence rotation ROM after reverse shoulder arthroplasty. MATERIAL AND METHODS: The Aequalis Reversed™ shoulder prosthesis (Tornier Inc., Edina, MN, USA) was implanted into 40 cadaver shoulders. Eight glenoid component combinations were tested, five with the 36-mm sphere (centred seating, eccentric seating, inferior tilt, centred with a 5-mm thick lateralised spacer, and centred with a 7-mm thick lateralised spacer) and three with the 42-mm sphere (centred with no spacer or with a 7-mm or 10-mm spacer). Humeral component position was evaluated with 0°, 10°, 20°, 30°, and 40° of retroversion. External and internal rotation ROMs to posterior and anterior impingement on the scapular neck were measured with the arm in 20° of abduction. RESULTS: The large glenosphere (42 mm) was associated with significantly (P<0.05) greater rotation ROMs, particularly when combined with a lateralised spacer (46° internal and 66° external rotation). Rotation ROMs were smallest with the 36-mm sphere. Greater humeral component retroversion was associated with a decrease in internal rotation and a significant increase (P<0.05) in external rotation. The best balance between rotation ROMs was obtained with the native retroversion, which was estimated at 17.5° on average in this study. DISCUSSION: Our anatomic study in a large number of cadavers involved a detailed and reproducible experimental protocol. However, we did not evaluate the variability in scapular anatomy. Earlier studies of the influence of technical parameters did not take humeral component retroversion into account. In addition, no previous studies assessed rotation ROMs. CONCLUSION: Rotation ROM should be improved by the use of a large-diameter glenosphere with a spacer to lateralise the centre of rotation of the gleno-humeral joint, as well as by positioning the humeral component at the patient's native retroversion value.

Meniscus matching: evaluation of direct anatomical, indirect radiographic, and photographic methods in 10 cadaver knees.

INTRODUCTION: When performing meniscus transplantation, allograft size must be carefully matched to the host knee anatomy. The radiographic method devised by Pollard et al. is the current reference standard for meniscus size matching. The primary objective of this study was to compare the accuracy of radiographic measurement according to Pollard, direct anatomic measurement, and photographic measurement. HYPOTHESIS: Anatomic and photographic allograft size measurement is as reliable as radiographic host-knee sizing according to Pollard et al. MATERIALS AND METHODS: Three methods for measuring meniscal width and length based on reliable landmarks were assessed in 10 cadaver knees: direct measurement of anatomic specimens, measurement of photographs, and the radiographic method described by Pollard et al. RESULTS: No significant differences were found between the anatomic and radiographic methods, whereas the anatomic and photographic methods produced significantly different results. Compared to the anatomic method, mean overall measurement error was 7.9% for the radiographic method and 24.1% for the photographic method. DISCUSSION: The photographic method used in everyday practice during allograft harvesting is not reliable. Correcting for magnification bias might improve the performance of the photographic method. The radiographic method described by Pollard et al. is acceptable, with a margin of error of about 10%, which is considered tolerable. In practice, however, the radiographic method is burdensome to use. CONCLUSION: The best measurement method is direct measurement of the specimen during allograft harvesting. LEVEL OF EVIDENCE: Level IV.

Rotational positioning of the tibial tray in total knee arthroplasty: a CT evaluation.

INTRODUCTION: Various surgical techniques have been described to set the rotational alignment of the tibial baseplate during total knee arthroplasty. The self-positioning method ("self-adjustment") aligns the tibial implant according to the rotational alignment of the femoral component which is used as a reference after performing repeated knee flexion/extension cycles. Postoperative computed tomography scanning produces accurate measurements of the tibial baseplate rotational alignment with respect to the femoral component. HYPOTHESIS: The rotational positioning of the tibial baseplate matches the rotation of the femoral component with parallel alignment to the prosthetic posterior bicondylar axis. PATIENTS AND METHODS: A 3-month follow-up CT scan was carried out after primary total knee arthroplasty implanted in osteoarthritic patients with a mean 7.8° varus deformity of the knee in 50 cases and a mean 8.7° valgus deformity of the knee in 44 cases. The NexGen LPS Flex (Zimmer) fixed-bearing knee prosthesis was used in all cases. An independant examiner (not part of the operating team) measured different variables: the angle between the anatomic transepicondylar axis and the posterior bicondylar axis of the femoral prosthesis (prosthetic posterior condylar angle), the angle between the posterior bicondylar axis and the posterior marginal axis of the tibial prosthesis, the angle between the posterior marginal axis of the tibial prosthesis and the posterior marginal axis of the tibial bone and finally the angle between the anatomic transepicondylar axis and the posterior marginal axis of the tibial prosthesis. RESULTS: For the genu varum and genu valgum subgroups, the mean posterior condylar axis of the femoral prosthesis was 3.1° (SD: 1.91; extremes 0° to 17.5°) and 4.7° (SD: 2.7; extremes 0° to 11°) respectively. The tibial baseplate was placed in external rotation with respect to the femoral component: 0.7° (SD : 4.45; extremes -9.5° to 9.8°) and 0.9° (SD: 4.53; extremes -10.8° to 9.5°), but also to the native tibia: 6.1° (SD: 5.85; extremes -4.6° to 22.5°) and 12.5° (SD: 8.6; extremes -10° to 28.9°). The tibial component was placed in internal rotation relative to the anatomic transepicondylar axis: 1.9° (SD : 4.93; extremes -13.6° to 7°) and 3° (SD : 4.38; extremes -16.2° to 4.8°). DISCUSSION: The tibial component is aligned parallel to the femoral component whatever the initial frontal deformity (P≅0.7). However, a difference was observed between the rotational alignment of the tibial baseplate and the native tibia depending on the initial deformity and could be attributed to the morphological variations of the bony tibial plateau in case of genu valgum. CONCLUSION: The self-positioning method is a reproducible option when using this type of implant since it allows the tibial component to be positioned parallel to the posterior border of the femur.

Massive rotator cuff tears in patients younger than 65 years. What treatment options are available?

Management of massive rotator cuff tears is a therapeutic challenge in patients younger than 65 years, particularly if still working. According to our hypothesis, choice of the most appropriate treatment option mainly depends on the patient's functional status and on two predictive factors: height of the subacromial space and fatty muscle infiltration. This is a retrospective, multicenter study of a series of 296 patients younger than 65 years, including 176 males and 120 females with extensive or massive cuff tear. Patients had loss of elevation or external rotation or both in 162 cases. Four types of management of massive rotator cuff tear were performed in this study: anatomical watertight repairs, palliative treatments and partial repairs, watertight repairs using flaps or cuff prostheses and reverse shoulder prostheses. At follow-up, the Constant score (65.6+/-3.4) and active elevation (147.7 degrees +/-32 degrees) had significantly improved. Active external rotation with elbow at the side, and acromiohumeral interval (AHI) were unchanged. Work-related injuries, previous surgeries and complications were correlated with a poorer Constant score. At follow-up, the anatomical repair sub-group had a significantly better Constant score than the three other treatment groups but involved patients with unchanged AHI and a low degree of fatty infiltration of the infraspinatus muscle. The reverse shoulder prostheses sub-group showed better outcomes in terms of function benefits. The presence of a long biceps was correlated with the use of a palliative treatment. In the light of the results and literature, an approach to treatment is suggested related to the functional capacity of patients, the AHI and the degree of fatty infiltration of the infraspinatus and subscapularis muscles.

Massive rotator cuff tears in patients younger than 65 years. Epidemiology and characteristics.

Currently, there is little information on the clinical, radiographic and electric profile of patients younger than 65 years of age with large rotator cuff tear. According to our hypothesis, massive rotator cuff tear, when discovered after recent traumatism, do not provide typical radiographic findings and suprascapular nerve impairment in large rotator cuff tears is uncommon. This is a prospective, descriptive, multicenter study of a series of 112 patients younger than 65 years, including 66 males and 46 females with extensive or massive cuff tear. Duration of symptoms was less than 6 months in 28 cases and secondary to trauma in 57 cases. Patients had loss of elevation or external rotation or both in 57 cases. An electromyogram (EMG) of suprascapular nerve was performed in 50 cases. A higher incidence of advanced fatty infiltration of the infraspinatus muscle (>stage 2 according to Goutallier) was observed in case of long-term symptomatology or in the absence of known trauma. Traumatic status was commonly found in patients with functional deficit in shoulder elevation, thus reporting a significantly lower Constant score (p<0.0001). Patients with both loss of shoulder elevation and external rotation had a significantly narrower subacromial space (5 mm versus 7.2 mm). No significant relationship could be established between electric impairment and massive cuff tear. According to the present study, in case of traumatic context and recent symptomatology, subacromial height and fatty infiltration of the infraspinatus muscle are better prognostic factors despite a pseudoparalytic shoulder. Repair should thus be considered. Moreover, the interest of a preoperative suprascapular nerve EMG is questionable.