Morpho-functional analysis of the temporomandibular joint following mandible-first bimaxillary surgery with mandible-only patient-specific implants.

The aim of this study was to evaluate condylar and glenoid fossa remodeling after bimaxillary orthognathic surgery guided by patient-specific mandibular implants. In total, 18 patients suffering from dentofacial dysmorphism underwent a virtually planned bimaxillary mandibular PSI-guided orthognathic procedure. One month prior to surgery, patients underwent a CBCT scan and optical scans of the dental arches; these datasets were re-acquired 1 month and at least 9 months postsurgery. Three-dimensional models of the condyles, glenoid fossae, and interarticular surface space (IASS) were obtained and compared to evaluate the roto-translational positional discrepancy and surface variation of each condyle and glenoid fossa, and the IASS variation. The condylar position varied by an average of 4.31° and 2.18 mm, mainly due to surgically unavoidable ramus position correction. Condylar resorption remodeling was minimal (average ≤ 0.1 mm), and affected skeletal class III patients the most. Later condylar remodeling was positively correlated with patient age. No significant glenoid fossa remodeling was observed. No postoperative orofacial pain was recorded at clinical follow-up. The procedure was accurate in minimizing the shift in relationship between the bony components of the TMJ and their remodeling, and was effective in avoiding postoperative onset of orofacial pain. An increase in sample size, however, would be useful to confirm our findings.

Prospective Evaluation of Posterior Glenoid Bone Loss After First-time and Recurrent Posterior Glenohumeral Instability Events.

BACKGROUND: Although posterior glenohumeral instability is becoming an increasingly recognized cause of shoulder pain, the role of posterior glenoid bone loss on outcomes remains incompletely understood. PURPOSES: To prospectively determine the amount of bone loss associated with posterior instability events and to determine predisposing factors based on preinstability imaging. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 1428 shoulders were evaluated prospectively for ≥4 years. At baseline, a subjective history of shoulder instability was ascertained for each patient, and bilateral noncontrast magnetic resonance imaging (MRI) scans of the shoulders were obtained regardless of any reported history of shoulder instability. The cohort was prospectively followed during the study period, and those who were diagnosed with posterior glenohumeral instability were identified. Postinjury MRI scans were obtained and compared with the screening MRI scans. Glenoid version, perfect-circle-based bone loss was measured for each patient's pre- and postinjury MRI scans using previously described methods. RESULTS: Of the 1428 shoulders that were prospectively followed, 10 shoulders sustained a first-time posterior instability event and 3 shoulders sustained a recurrent posterior instability event. At baseline, 11 of 13 shoulders had some amount of glenoid dysplasia and/or bone loss. The change in glenoid bone loss was 5.4% along the axis of greatest loss (95% CI, 3.8%-7.0%; P = .009), 4.4% at the glenoid equator (95% CI, 2.7%-6.2%; P = .016), and 4.2% of total glenoid area (95% CI, 2.9%-5.3%; P = .002). Recurrent glenoid instability was associated with a greater amount of absolute bone loss along the axis of greatest loss compared with first-time instability (recurrent: 16.8% ± 1.1%; 95% CI, 14.6%-18.9%; first-time: 10.0% ± 1.5%; 95% CI, 7.0%-13.0%; P = .005). Baseline glenoid retroversion ≥10° was associated with a significantly greater percentage of bone loss along the axis of greatest loss (≥10° of retroversion: 13.5% ± 2.0%; 95% CI, 9.6%-17.4%; <10° of retroversion: 8.5% ± 0.8%; 95% CI, 7.0%-10.0%; P = .045). CONCLUSIONS: Posterior glenohumeral instability events were associated with glenoid bone loss of 5%. The amount of glenoid bone loss after a recurrent posterior glenohumeral instability event was greater than that after first-time instability. Glenoid retroversion ≥10° was associated with a greater amount of posterior glenoid bone loss after a posterior instability event.

The association between anterior shoulder joint capsule thickening and glenoid deformity in primary glenohumeral osteoarthritis.

BACKGROUND: Anterior shoulder joint capsule thickening is typically present in osteoarthritic shoulders, but its association with specific patterns of glenoid wear is incompletely understood. We sought to determine the relationship between anterior capsular thickening and glenoid deformity in primary glenohumeral osteoarthritis. METHODS: We retrospectively identified 134 consecutive osteoarthritic shoulders with magnetic resonance imaging and computed tomography scans performed. Axial fat-suppressed magnetic resonance imaging slices were used to quantify the anterior capsular thickness in millimeters, measured at its thickest point below the subscapularis muscle. Computed tomography scans were used to classify glenoid deformity according to the Walch classification, and an automated 3-dimensional software program provided values for glenoid retroversion and humeral head subluxation. Multinomial and linear regression models were used to characterize the association of anterior capsular thickening with Walch glenoid type, glenoid retroversion, and posterior humeral head subluxation while controlling for patient age and sex. RESULTS: The anterior capsule was thickest in glenoid types B2 (5.5 mm, 95% confidence interval [CI]: 5.0-6.0) and B3 (6.1 mm, 95% CI: 5.6-6.6) and thinnest in A1 (3.7 mm, 95% CI: 3.3-4.2; P < .001). Adjusted for age and sex, glenoid types B2 (odds ratio: 4.4, 95% CI: 2.3-8.4, P < .001) and B3 (odds ratio: 5.4, 95% CI: 2.8-10.4, P < .001) showed the strongest association with increased anterior capsule thickness, compared to glenoid type A1. Increased capsular thickness correlated with greater glenoid retroversion (r = 0.57; P < .001) and posterior humeral head subluxation (r = 0.50; P < .001). In multivariable analysis, for every 1-mm increase in anterior capsular thickening, there was an adjusted mean increase of 3.2° (95% CI: 2.4-4.1) in glenoid retroversion and a 3.8% (95% CI: 2.7-5.0) increase in posterior humeral head subluxation. CONCLUSIONS: Increased thickening of the anterior shoulder capsule is associated with greater posterior glenoid wear and humeral head subluxation. Additional research should determine whether anterior capsular disease plays a causative role in the etiology or progression of eccentric glenohumeral osteoarthritis.

Relationship Between Glenoid Component Shift and Osteolysis After Anatomic Total Shoulder Arthroplasty: Three-Dimensional Computed Tomography Analysis.

BACKGROUND: The purpose of this study was to evaluate glenoid component position and radiolucency following anatomic total shoulder arthroplasty (TSA) using sequential 3-dimensional computed tomography (3D CT) analysis. METHODS: In a series of 152 patients (42 Walch A1, 16 A2, 7 B1, 49 B2, 29 B3, 3 C1, 3 C2, and 3 D glenoids) undergoing anatomic TSA with a polyethylene glenoid component, sequential 3D CT analysis was performed preoperatively (CT1), early postoperatively (CT2), and at a minimum 2-year follow-up (CT3). Glenoid component shift was defined as a change in component version or inclination of ≥3° from CT2 to CT3. Glenoid component central anchor peg osteolysis (CPO) was assessed at CT3. Factors associated with glenoid component shift and CPO were evaluated. RESULTS: Glenoid component shift occurred from CT2 to CT3 in 78 (51%) of the 152 patients. CPO was seen at CT3 in 19 (13%) of the 152 patients, including 15 (19%) of the 78 with component shift. Walch B2 glenoids with a standard component and glenoids with higher preoperative retroversion were associated with a higher rate of shift, but not of CPO. B3 glenoids with an augmented component and glenoids with greater preoperative joint-line medialization were associated with CPO, but not with shift. More glenoid component joint-line medialization from CT2 to CT3 was associated with higher rates of shift and CPO. A greater absolute change in glenoid component inclination from CT2 to CT3 and a combined absolute glenoid component version and inclination change from CT2 to CT3 were associated with CPO. Neither glenoid component shift nor CPO was associated with worse clinical outcomes. CONCLUSIONS: Postoperative 3D CT analysis demonstrated that glenoid component shift commonly occurs following anatomic TSA, with increased inclination the most common direction. Most (81%) of the patients with glenoid component shift did not develop CPO. Longer follow-up is needed to determine the relationships of glenoid component shift and CPO with loosening over time. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Reverse Total Shoulder Arthroplasty without Bone-Grafting for Severe Glenoid Bone Loss in Patients with Osteoarthritis and Intact Rotator Cuff: A Concise 5-Year Follow-up of a Previous Report.

LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Anatomical relationships of the transmuscular portal to its surrounding structures in arthroscopic treatment of superior labrum anterior posterior lesions: A cadaveric study and preliminary report.

OBJECTIVE: This study aims to investigate the anatomical relationships of the transmuscular portal to its surrounding structures in arthroscopic treatment of superior labrum anterior posterior (SLAP) lesions in a human cadaveric model. METHODS: In this anatomic study, bilateral shoulder girdles of 12 adult formalin embalmed cadavers were used. All cadavers were male, and the mean age was 63.4±7.3 years. The portal entry point was determined as midway between the anterior and posterior borders of the acromion, approximately 1 cm lateral from the edge of the acromion. After a guidewire was placed in the glenoid cavity at the 12 o'clock position where the SLAP lesion typically occurs, a switching stick was inserted there. Each glenoid was then drilled with a 2.4 mm drill through an arthroscopic cannula. Subsequently, anatomical dissection was executed to assess the relationship of the transmuscular portal with the suprascapular nerve, axillary nerve, supraspinatus tendon, acromion, and biceps tendon. Lastly, the shortest distance between the aforementioned structures with the drill was measured by a sensitive caliper to determine whether there was a penetration of the structures. Differences between the right and left sides were analyzed. RESULTS: The mean distance between the portal and the axillary nerve was 55.5 mm±6.0 mm, and the mean length of the suprascapular nerve was 61.2 mm±7.0 mm. The mean distance between the portal and the supraspinatus tendon was 2.8 mm±1.5 mm. No penetration of the axillary nerve, suprascapular nerve, and supraspinatus tendon was observed in any cadaver. No differences were detected for measured anatomical parameters between the right and left sides (p>0.05). CONCLUSION: Findings from this cadaveric study revealed that the transmuscular portal may allow for a reliable anchor placement without any nerve or tendon penetration during arthroscopic SLAP repair. LEVEL OF EVIDENCE: Level V.

Arthroscopic Bankart repair with remplissage versus Latarjet procedure for management of engaging Hill-Sachs lesions with subcritical glenoid bone loss in traumatic anterior shoulder instability: a systematic review and meta-analysis.

BACKGROUND: A large engaging Hill-Sachs lesion (HSL) with subcritical glenoid bone loss (GBL) is approached through either increasing the glenoid arc by the Latarjet procedure or converting the HSL to an extra-articular defect by arthroscopic Bankart repair with remplissage (BRR). Until now, there has been no evidence-based consensus about which of these 2 most appropriate procedures is the better surgical choice. The purpose of this study was to analyze the current literature comparing results of BRR vs. the Latarjet procedure in the treatment of engaging HSLs with subcritical GBL. METHODS: A comprehensive review of the PubMed and Cochrane databases was completed for studies that compared the clinical outcomes and complications of BRR vs. the Latarjet procedure with minimum follow-up of 2 years. The outcome measures analyzed included postoperative Rowe score, visual analog scale pain score, postoperative range of motion (ROM), and rates of recurrent instability and other complications. RESULTS: Overall, 4 articles (level III evidence in 3 and level II in 1) were included from an initial 804 abstracts. The study population consisted of a total of 379 patients, of whom 194 underwent BRR and 185 underwent the Latarjet procedure. There were no unacceptable differences in baseline characteristics between the 2 groups. For the rate of recurrent instability, both groups had comparable risk ratios (RRs) (N = 379; RR, 0.72; 95% confidence interval [CI], 0.37-1.41). The risk of other complications was significantly increased with the Latarjet procedure (by about 7 times) relative to the the BRR procedure (N = 379; RR, 7.37; 95% CI, 2-27). Both groups had comparable postoperative Rowe scores (n = 190; mean difference [MD], -0.9; 95% CI, -3.45 to 1.7) and visual analog scale pain scores (n = 347; MD, -0.2; 95% CI, -0.6 to 0.2). Moreover, both groups had comparable postoperative external rotation ROM (MD, -1.7°; 95% CI, -9.4° to 6°) and internal rotation ROM (MD, 1.95°; 95% CI, -5.35° to 9.25°). There was substantial heterogeneity in the effect of both procedures on postoperative pain and ROM (external rotation and internal rotation). CONCLUSION: Both the BRR and Latarjet procedures are effective for the management of engaging HSLs with subcritical GBL and give comparable clinical outcomes. However, given the fewer overall postoperative complications, remplissage may be safer. The results of the included studies were adequately consistent for most analyzed outcomes. However, for the intervention effect on postoperative pain and ROM, there was a small body of evidence, limiting the strength of the reported conclusions.

Mechanism and patterns of bone loss in patients with anterior shoulder dislocation.

BACKGROUND: Bony defects are common injuries associated with anterior shoulder dislocation. It is generally thought that these bony defects are created at the time of dislocation. However, there have been no biomechanical reports demonstrating the exact time point when these lesions occur. The purpose of this study was to clarify when, how, and which types of bony defects were created during experimental dislocation in cadaveric shoulders. METHODS: Fifteen fresh-frozen cadaveric shoulders (mean age at the time of death, 79 years) were fixed in a custom testing machine. First, the glenohumeral joint was inspected by arthroscopy. Then, the arm was held at 60° of abduction and maximum external rotation and was manually extended horizontally under fluoroscopy until an anterior dislocation occurred. Next, a force of 800 N was applied to a Kirschner wire inserted in the humeral head in the direction of the pectoralis major with use of an air cylinder. We waited until the arm came to equilibrium under this condition. Finally, the glenohumeral joint was arthroscopically examined. We further performed x-ray micro-computed tomography and histologic examination in 1 shoulder with a bipolar lesion. RESULTS: After the anterior dislocation, a Bankart lesion was created in 9 of 15 shoulders and a fragment-type glenoid defect (avulsion fracture) was created in 4. A Hill-Sachs lesion, on the other hand, was not observed after the dislocation. The equilibrium arm position was 40° ± 17° in flexion, 45° ± 22° in abduction, and 27° ± 19° in external rotation. In this arm position, newly created lesions were Hill-Sachs lesions in 6 shoulders and erosion-type glenoid defects (compression fracture) in 7. Micro-computed tomography, performed in a single specimen, showed a flattened anterior glenoid rim with collapse of trabecular bone. Histologic analysis of nondecalcified sections using hematoxylin-eosin staining indicated that the anterior rim of the glenoid was compressed and flattened. The cortex of the anterior glenoid rim could be clearly observed. CONCLUSION: The fragment-type glenoid defect (avulsion fracture) was observed at the time of dislocation, whereas the erosion-type defect (compression fracture) was observed when the arm came to equilibrium in the midrange of motion. Hill-Sachs lesions were created not at the time of dislocation but after the arm came to equilibrium.

Early results of reverse total shoulder arthroplasty using a patient-matched glenoid implant for severe glenoid bone deficiency.

BACKGROUND: Reverse total shoulder arthroplasty (rTSA) in the presence of significant glenoid bone loss remains a challenge. This study presents preliminary clinical and radiographic outcomes of primary and revision rTSA using a patient-matched, 3-dimensionally printed custom metal glenoid implant to address severe glenoid bone deficiency. METHODS: Between September 2017 and November 2018, 19 patients with severe glenoid bone deficiency underwent primary (n = 9) or revision rTSA (n = 10) using the Comprehensive Vault Reconstruction System (VRS) (Zimmer Biomet, Warsaw, IN, USA) at a single institution. Preoperative and postoperative values for the Disabilities of the Arm, Shoulder and Hand score, Constant score, American Shoulder and Elbow Surgeons score, Simple Shoulder Test score, Single Assessment Numeric Evaluation score, and visual analog scale pain score and active range of motion were compared using the Wilcoxon signed rank test with the level of statistical significance set at P < .05. RESULTS: Complications occurred in 4 patients (21%), including a nondisplaced greater tuberosity fracture treated conservatively in 1, intraoperative cortical perforation during humeral cement removal treated with an allograft strut in 1, and recurrent instability and hematoma formation treated with humeral component revision in 1. One patient with an early periprosthetic infection was treated with component removal and antibiotic spacer placement at an outside facility and was subsequently lost to follow-up. Eighteen patients with 1-year minimum clinical and radiographic follow-up were evaluated (mean, 18.2 months; range, 12-27 months). Significant improvements were noted in the mean Disabilities of the Arm, Shoulder and Hand score (57.4 ± 16.5 vs. 29.4 ± 19.5, P < .001), mean Constant score (24.6 ± 10.2 vs. 60.4 ± 14.5, P < .001), mean American Shoulder and Elbow Surgeons score (32 ± 18.2 vs. 79 ± 15.6, P < .001), mean Simple Shoulder Test score (4.5 ± 2.6 vs. 9.3 ± 1.8, P < .001), mean Single Assessment Numeric Evaluation score (25.4 ± 13.7 vs. 72.2 ± 17.8, P < .001), mean visual analog scale pain score (6.2 ± 2.9 vs. 0.7 ± 1.3, P < .001), mean active forward flexion (53° ± 27° vs. 124° ± 23°, P < .001), and mean active abduction (42° ± 17° to 77° ± 15°, P < .001). Mean external rotation changed from 17° ± 19° to 32° ± 24° (P = .06). No radiographic evidence of component loosening, scapular notching, or hardware failure was observed at last follow-up in any patient. CONCLUSION: The preliminary results of rTSA using the VRS to manage severe glenoid bone deficiency are promising, but longer follow-up is necessary to determine the longevity of this implant.

When to Abandon the Arthroscopic Bankart Repair: A Systematic Review.

CONTEXT: Bone loss is a major factor in determining surgical choice in patients with anterior glenohumeral instability. Although bone loss has been described, there is no consensus on glenoid, humeral head, and bipolar bone loss limits for which arthroscopic-only management with Bankart repair can be performed. OBJECTIVE: To provide guidelines for selecting a more complex repair or reconstruction (in lieu of arthroscopic-only Bankart repair) in the setting of glenohumeral instability based on available literature. DATA SOURCES: An electronic search of the literature for the period from 2000 to 2019 was performed using PubMed (MEDLINE). STUDY SELECTION: Studies were included if they quantified bone loss (humeral head or glenoid) in the setting of anterior instability treated with arthroscopic Bankart repair. STUDY DESIGN: Systematic review. LEVEL OF EVIDENCE: Level 4. DATA EXTRACTION: Study design, level of evidence, patient demographics, follow-up, recurrence rates, and measures of bone loss (glenoid, humeral head, bipolar). RESULTS: A total of 14 studies met the inclusion criteria. Of these, 10 measured glenoid bone loss, 5 measured humeral head bone loss, and 2 measured "tracking" without explicit measurement of humeral head bone loss. Measurement techniques for glenoid and humeral head bone loss varied widely. Recommendations for maximum glenoid bone loss for arthroscopic repair were largely <15% of glenoid width in recent studies. Recommendations regarding humeral head loss were more variable (many authors providing only qualitative descriptions) with increasing attention on glenohumeral tracking. CONCLUSION: It is essential that a standardized method of glenoid and humeral head bone loss measurements be performed preoperatively to assess which patients will have successful stabilization after arthroscopic Bankart repair. Glenoid bone loss should be <15%, and humeral head lesions should be "on track" if an arthroscopic-only Bankart is planned. If there is greater bone loss, adjunct or open procedures should be performed.

Effects of Glenoid and Humeral Bone Defects on Recurrent Anterior Instability of the Shoulder.

For proper treatment of recurrent anterior instability of the shoulder with a bone defect, the defect size should be assessed preoperatively with three-dimensional computed tomography or magnetic resonance imaging. In general, the risk of postoperative recurrence of instability is estimated on the basis of preoperative imaging of bipolar bone defects: more than 20%-25% glenoid bone loss and off-track Hill-Sachs lesions have been considered risk factors for recurrence. In patients with a glenoid bone defect more than 20%-25%, a bone graft procedure, such as the Latarjet procedure, is preferred regardless of the glenoid track concept, because compared with arthroscopic stabilization procedure, it provides greater postoperative stability. For patients with a borderline glenoid bone defect (around 20%), surgeons should discuss surgical options with the patients, considering their demand and physical activity level. In addition, the surgeon should take care to prevent postoperative instability and long-term complications. Arthroscopic soft-tissue reconstruction including labral repair and capsular plication combined with the additional remplissage procedure is an anatomical procedure and could be considered as one of the primary treatment methods for patients with glenoid bone defects around 20%. Therefore, treatment strategies for recurrent anterior shoulder instability combined with bone defects should be determined more flexibly on the basis of the patient's individual condition.

Use of the Contralateral Glenoid for Calculation of Glenoid Bone Loss: A Cadaveric Anthropometric Study.

PURPOSE: The purpose of this study was to determine if there are significant side-to-side anthropometric differences between paired glenoids. METHODS: Forty-six matched-pair cadaver glenoids were harvested, and their glenoid heights (GHs) and glenoid widths (GWs) were measured with digital calipers. The glenoid surface area was calculated using the standard assumption that the inferior two-thirds of the glenoid is a perfect circle. RESULTS: There was a statistically significant difference between matched-pair GHs of 0.96 ± 3.07 mm (P = .020) and GWs of 0.46 ± 1.64 mm (P = .033). There was a significant difference of glenoid cavity area of 20.30 ± 81.53 mm2 (P = .044), or a difference of ∼3%. A total of 4 of 46 pairs of glenoids (8.6%) showed a difference in width >3 mm. CONCLUSIONS: This study demonstrates the fallacy of use of the contralateral glenoid in measuring glenoid bone loss. Although many paired samples exhibited similar side-to-side glenoid measurements, the number of cadaveric pairs that showed differences of >3 mm was substantial. Caution should be taken when using calculation methods that include this assumption for surgical decision making, as surface area, GW, and GH were all shown to have statistically significant side-to-side differences in their measurements. CLINICAL RELEVANCE: Many methods exist for measuring glenoid bone loss after anterior shoulder dislocation, but some of the current methods may be inaccurate and lead to unreliable estimations.

Automated quantification of glenoid bone defects using 3-dimensional measurements.

BACKGROUND: Assessment of glenoid bone defects is important to select the optimal glenoid component design during shoulder arthroplasty planning and implantation. This study presents a fully automated method to describe glenoid bone loss using 3-dimensional measurements without the need for a healthy contralateral reference scapula. METHODS: The native shape of the glenoid is reconstructed by fitting a statistical shape model (SSM) of the scapula. The total vault loss percentage, local vault loss percentages, defect depth, defect area percentage, and subluxation distance and region are computed based on a comparison of the reconstructed and eroded glenoids. The method is evaluated by comparing its results with a contralateral bone-based reconstruction approach in a data set of 34 scapula and humerus pairs with unilateral glenoid bone defects. RESULTS: The SSM-based defect measurements deviated from the contralateral bone-based measurements with mean absolute differences of 5.5% in the total vault loss percentage, 4.5% to 8.0% in the local vault loss percentages, 1.9 mm in the defect depth, 14.8% in the defect area percentage, and 1.6 mm in the subluxation distance. The SSM-based method was statistically equivalent to the contralateral bone-based method for all parameters except the defect area percentage. CONCLUSION: The presented method is able to automatically analyze glenoid bone defects using 3-dimensional measurements without the need for a healthy contralateral bone.

Return to sports after glenoid reconstruction using an implant-free iliac crest bone graft.

PURPOSE: The purpose of this study was to evaluate sports ability and the rate of return to sports after implant-free iliac bone graft for recurrent, anterior shoulder instability and anterior glenoid bone loss. Subgroups of younger and older patients and patients who had previous arthroscopic Bankart surgery and those who did not have such surgery before implant-free iliac bone graft were formed and compared. METHODS: We retrospectively analyzed 34 patients; 14 patients had previous arthroscopic Bankart surgery, and 20 patients did not have the surgery; The median age at the time of iliac bone graft was 35.3 years (range, 23 to 75), 17 patients were over the age of 35, and 17 patients were under the age of 35. The mean follow-up was 40 months (range: 25 to 56). RESULTS: All the 34 patients were engaged in pre- and post-operative sport, which represents a return to sport rate of 100%. Although the number of sport disciplines decreased significantly from 6 before the operation to 4.8 after the operation (p=0.002), the number of sports sessions per week did not change significantly, and the duration per session did not change significantly. More than two-thirds of all patients returned to sports within 6 months. Overall, 41% of patients changed sport disciplines, 15% of whom cited shoulder-related causes; however, all patients returned to the same sport level. CONCLUSIONS: Overall and within the subgroups, the return to sport rate after implant-free iliac bone grafting was high, with a high sense of well-being. The number of sport disciplines decreased significantly and more than one-third of the patients changed disciplines, of which 15% percent changed due to shoulder-related causes. The sport level remained equal, and no other parameters changed significantly compared with the time before the onset of restrictive shoulder symptoms.

Reverse shoulder arthroplasty for patients with glenohumeral osteoarthritis secondary to glenoid dysplasia.

The purpose is to report the clinical and radiographic outcomes, complications and reoperations of reverse shoulder arthroplasty (RSA) for glenoid dysplasia. All patients who had undergone RSA for osteoarthritis secondary to underlying glenoid dysplasia were retrospectively identified. The study included twelve shoulders (11 patients), with a mean (SD) patient age of 62.2 (13.2) years and median (range) clinical follow-up of 28 (24-34) months. RSA resulted in substantial improvements in pain and function. At most recent follow-up, there was a significant improvement in forward flexion range of motion (ROM), a non-significant improvement in internal rotation ROM, and no changes in external rotation ROM. The mean (SD) SST and ASES scores were 7.8 (3.7) and 73.5 (20.4), respectively. There were no reoperations or radiographic loosening. The results were excellent in 1 case, satisfactory in 8, and unsatisfactory in 3. RSA provides acceptable function and good pain relief, though patients should be advised that shoulder rotation may be somewhat limited.

Effect of subcritical glenoid bone loss on activities of daily living in patients with anterior shoulder instability.

BACKGROUND: It has been biomechanically demonstrated that 20% to 25% is a critical glenoid bone loss. Recently, there are several reports describing that a bone loss less than 20% to 25% needed to be treated because patients may have decreased quality of life without recurrent instability events. The purpose of this study was to clarify the presence of subcritical bone loss that would affect postoperative instability or quality of life. METHODS: Subjects were 43 patients aged≤40years with less than 25% glenoid bone loss who had undergone arthroscopic Bankart repair. These patients were assessed at a mean follow-up of 32months. The Western Ontario Shoulder Instability (WOSI) and Rowe scores were used for the clinical evaluation. Patients were divided in 3 groups based on the percentage of bone loss: group 1: <8%; group 2: 8% to 17%; and group 3: >17%. RESULTS: The recurrence rate was 7% (3/43 shoulders). A weak negative correlation was seen between bone loss and sports/recreation/work domain of the WOSI score (r=-0.304, p=0.0191). The WOSI for group 3 was significantly lower than that for group 1 and 2 (p=0.0009). The male WOSI scores were significantly lower than the female ones (p=0.0471). The WOSI scores of the contact athletes were significantly lower than those of non-contact athletes (p=0.0275). All the patients in Group 3 were males and participated in contact sports. CONCLUSION: Glenoid bone loss between 17% and 25% is considered to be a "subcritical bone loss" in our series, especially in male patients who are involved in sports or high-level activities. LEVEL OF EVIDENCE: III, retrospective study.

Association Between Rotator Cuff Muscle Size and Glenoid Deformity in Primary Glenohumeral Osteoarthritis.

BACKGROUND: Although glenoid morphology has been associated with fatty infiltration of the rotator cuff in arthritic shoulders, the association of rotator cuff muscle area with specific patterns of glenoid wear has not been studied. The purpose of our study was to assess the associations of glenoid deformity in primary glenohumeral osteoarthritis and rotator cuff muscle area. METHODS: A retrospective study of 370 computed tomographic (CT) scans of osteoarthritic shoulders was performed. Glenoid deformity according to the modified Walch classification was determined, and retroversion, inclination, and humeral-head subluxation were calculated using automated 3-dimensional software. Rotator cuff muscle area was measured on sagittal CT scan reconstructions. A ratio of the area of the posterior rotator cuff muscles to the subscapularis was calculated to approximate axial plane potential force imbalance. Univariate and multivariate analyses to determine associations with glenoid bone deformity and rotator cuff measurements were performed. RESULTS: Patient age and sex were significantly related to cuff muscle area across glenoid types. Multivariate analysis did not find significant differences in individual rotator cuff cross-sectional areas across glenoid types, with the exception of a larger supraspinatus area in Type-B2 glenoids compared with Type-A glenoids (odds ratio [OR], 1.5; p = 0.04). An increased ratio of the posterior cuff area to the subscapularis area was associated with increased odds of a Type-B2 deformity (OR, 1.3; p = 0.002). Similarly, an increase in this ratio was significantly associated with increased glenoid retroversion (beta = 0.92; p = 0.01) and humeral-head subluxation (beta = 1.48; p = 0.001). Within the Type-B glenoids, only posterior humeral subluxation was related to the ratio of the posterior cuff to the subscapularis (beta = 1.15; p = 0.001). CONCLUSIONS: Age and sex are significantly associated with cuff muscle area in arthritic shoulders. Asymmetric glenoid wear and humeral-head subluxation in osteoarthritis are associated with asymmetric atrophy within the rotator cuff transverse plane. Increased posterior rotator cuff muscle area compared with anterior rotator cuff muscle area is associated with greater posterior glenoid wear and subluxation. It is unclear if the results are causative or associative; further research is required to clarify the relationship. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Characterization of Posterior Glenoid Bone Loss Morphology in Patients With Posterior Shoulder Instability.

PURPOSE: To systemically describe posterior bone defects in the setting of posterior shoulder instability based on several parameters, including surface area, slope and version, defect height from the base of the glenoid, and extent of bone loss at equal intervals along the long axis of the fossa. METHODS: A total of 40 young, active individuals with recurrent posterior shoulder instability and a bony injury confirmed on either computed tomography (n = 18; mean age, 26.3 ± 4.0 years) or magnetic resonance imaging (n = 22; mean age, 20.0 ± 4.9 years) were identified. The posterior glenoid bone defect was characterized using the following measures: (1) percentage of bone loss, (2) glenoid vault version, (3) slope of the posterior defect relative to the glenoid surface, (4) superior-inferior length of the defect, and (5) anterior-posterior width of the defect at 5 intervals along the glenoid fossa. RESULTS: The mean age of the 40 patients was 22.9 ± 5.5 years (range, 14.9-35.5 years). The mean surface area of glenoid bone loss was 9.7% ± 4.7%. Glenoid version measured at 5 equal intervals along the inferior two-thirds of the glenoid was 12.8° ± 4.9°, 11.9° ± 5.0°, 10.1° ± 6.3°, 10.5° ± 6.5°, and 8.7° ± 7.2° from superior to inferior. The mean slope of the posterior defect relative to the glenoid fossa was 26.8° ± 11.5°. The mean superior-inferior height of the bony defect was 21.9 ± 0.4 mm. The anterior-posterior sloped width of the defect at 5 equal intervals along the glenoid fossa was 0.9 ± 1.5 mm, 2.8 ± 2.4 mm, 4.0 ± 1.7 mm, 4.0 ± 2.1 mm, and 2.9 ± 2.6 mm from superior to inferior. Low-grade (<10%) bone loss was diagnosed in most shoulders (23 of 40 evaluated), whereas 15 had moderate bone loss (10% to <20%) and 2 had high-grade bone loss (≥20%). CONCLUSIONS: Posterior glenoid bone loss is characterized by a loss of posterior bony concavity, increased slope from anterior to posterior, and increased posterior version. The most anterior-posterior sloped width was quantified at the third and fourth intervals of 5 equal intervals from superior to inferior. This study highlights that patients with posterior instability have bone loss that is sloped relative to the glenoid fossa and suggests that management must be appropriately tailored given the distinctiveness of posterior bone loss. LEVEL OF EVIDENCE: Level IV, case series.

Mid-term results of reverse shoulder arthroplasty for glenohumeral osteoarthritis with posterior glenoid deficiency and humeral subluxation.

BACKGROUND: Results of anatomic shoulder arthroplasty for glenohumeral osteoarthritis with severe glenoid retroversion are unpredictable with a high rate of glenoid loosening. Reverse shoulder arthroplasty (RSA) has been suggested as an alternative, with good early results. We sought to confirm this at longer follow-up (minimum 5 years). The study hypothesis was that early results would endure over time. METHODS: We retrospectively reviewed all RSAs performed in 7 centers from 1998 to 2010. The inclusion criteria were primary glenohumeral osteoarthritis with B1, B2, B3, or C glenoid. Forty-nine shoulders in 45 patients fulfilled the criteria. Bone grafting was performed in 16 cases. Clinical outcomes were evaluated with the Constant score (CS) and shoulder range of motion. RESULTS: The mean total CS increased from 30 preoperatively to 68 points (P < .001) with significant improvements in all the subsections of the CS and range of motion. Scapular notching was observed in 20 shoulders (43%), grade 1 in 5 (11%), grade 2 in 7 (15%), grade 3 in 5 (11%), and grade 4 in 3 (6%). The glenoid bone graft healed in all the shoulders. Partial inferior lysis of the bone graft was present in 8 cases (50%). Scapular notching and glenoid bone graft resorption had no influence on the CS (P = .147 and P = .798). CONCLUSION: RSA for the treatment of primary glenohumeral osteoarthritis in patients with posterior glenoid deficiency and humeral subluxation without rotator cuff insufficiency resulted in excellent clinical outcomes at a minimum of 5 years of follow-up.

Bone defect-induced alteration in glenoid articular surface geometry and restoration with coracoid transfer procedures: a cadaveric study.

BACKGROUND: This study analyzed the alteration in glenoid articular geometry with increasing anterior bone loss, as well as its subsequent correction with 2 modifications of the Latarjet procedure. METHODS: Anterior defects were simulated by creating glenoid osteotomies (10%, 20%, 30%, and 40%), and defects were reconstructed using 2 Latarjet modifications (classic and congruent arc). A total of 108 computed tomography scans were performed (1) on intact scapulae (n = 12), (2) after each bone defect (n = 48), and (3) after each reconstruction (n = 48). Glenoid parameters (width, area, arc length, and version) were analyzed on computed tomography scans. Statistical analysis was used to determine significant differences between intact, deficient, and reconstructed glenoids. RESULTS: All parameters were reduced with every 10% defect increment (mean change in width, 2.5 mm; area, 64 mm2; version, 2.2°; and arc length, 2.2 mm). Width correction with the classic Latarjet procedure was not statistically significant in 30% and 40% defects. Area correction in 30% defects was not significant with the classic Latarjet procedure and was significantly undercorrected in 40% defects. Version correction was not significant after the classic Latarjet procedure in 20%, 30%, and 40% defects. Arc-length correction was not significant in 20% and 30% defects with the classic Latarjet procedure and was significantly undercorrected in 40% defects. The congruent-arc Latarjet procedure overcorrected glenoid parameters in all defects; however, area and arc length were not significantly different from intact glenoids in 40% defects (P < .05). CONCLUSION: Glenoid articular geometry is progressively altered with a sequential increase in anterior bone defects from 0% to 40%. The classic Latarjet procedure provided significant correction in bone defects of 10% and 20%. The congruent-arc Latarjet procedure restored and overcorrected most parameters even in 40% glenoid defects.