Posterior Subluxation Research Articles

Three-dimensional measures of posterior bone loss and retroversion in Walch B2 glenoids predict the need for an augmented anatomic glenoid component.

The purpose of this study is to evaluate whether the amount of measured posterior bone loss on 2- and 3-dimensional (2D and 3D) imaging of Walch B2 glenoids can reliably predict the plan for an augmented anatomic glenoid component. Patients with Walch B2 glenoids and preoperative computed tomography (CT) scans were retrospectively identified. 2D axial CT scans were reviewed and posterior bone loss was measured by 3 independent reviewers. Images were then formatted into BluePrint (Wright Medical) preoperative planning software. The same 3 reviewers again measured posterior bone loss on 3D imaging. Additionally, all cases were planned with BluePrint software. An augment was used when the following criteria were unable to be satisfied with standard implants: <10° retroversion, <10° superior inclination, ≥90% backside contact, <2 mm medial reaming, and ≤1 peg perforation. Forty-two patients were included in the final analysis with a mean age of 63.1 ± 6.3 years. As measured by BluePrint, the mean retroversion was 23° ± 7° (range = 9°-40°), the mean superior inclination was 5° ± 6° (range = -9° to 22°), and the mean posterior subluxation was 80% ± 17% (range = 41%-95%). The mean 2D bone loss measurements (3.5 ± 1.6 mm) were significantly lower than the mean 3D bone loss (4.0 ± 1.8 mm) measurements (P = .03). There was substantial agreement between reviewers on both 2D and 3D measurements with an interclass correlation of 0.815 (95% confidence interval [CI] 0.714-0.889, P < .001) and an interclass correlation of 0.802 (95% CI 0.683-0.884, P < .001), respectively. Augments were used in 73.8%, 63.4%, and 63.4% of cases by reviewers 1, 2, and 3, respectively, with moderate agreement with a Fleiss kappa of 0.592 (95% CI 0.416-0.769, P < .001). Augment size was moderately, positively correlated with the amount of bone loss on 3D imaging but not with 2D imaging. After multivariate logistic regression, both 3D bone loss and retroversion were found to be predictive for a plan to use an augment. Planning for a posterior augment in Walch B2 glenoids is better predicted with 3D imaging than with 2D imaging, as 2D imaging may underestimate posterior bone loss. Additionally, use of a larger augment size is moderately correlated with posterior bone loss on 3D imaging but not 2D imaging. Standard 2D imaging may be limited in cases of posterior bone loss, and 3D imaging may be beneficial for preoperative planning in Walch B2 glenoids.

Muscle volume imbalance may be associated with static posterior humeral head subluxation

BackgroundThe transverse force couple (TFC) of the rotator cuff (subscapularis vs. infraspinatus and teres minor muscle) is an important dynamic stabilizer of the shoulder joint in the anterior-posterior direction. In patients with posterior static subluxation of the humeral head (PSSH), decentration of the humeral head posteriorly occurs, which is associated with premature arthritis. We hypothesize that not only pathologic glenoid retroversion but also chronic muscle volume imbalance in the transverse force couple leads to PSSH.MethodsA retrospective analysis of the TFC muscle volumes of 9 patients with symptomatic, atraumatic PSSH, within 8 were treated with glenoid correction osteotomy, was conducted. The imaging data (CT) of 9 patients/10 shoulders of the full scapula and shoulder were analyzed, and the muscle volumes of the subscapularis (SSC), infraspinatus (ISP) and teres minor muscles (TMM) were measured by manually marking the muscle contours on transverse slices and calculating the volume from software. Furthermore, the glenoid retroversion and glenohumeral distance were measured.ResultsThe mean glenoid retroversion was − 16° (− 7° to − 31°). The observed mean glenohumeral distance was 4.0 mm (0 to 6.8 mm). Our study population showed a significant muscle volume imbalance between the subscapularis muscle and the infraspinatus and teres minor muscles (192 vs. 170 ml; p = 0.005). There was no significant correlation between the subscapularis muscle volume and the glenohumeral distance (r = 0.068), (p = 0.872).ConclusionThe muscle volume of the SSC in patients with PSSH was significantly higher than the muscle volume of the posterior force couple (ISP and TMM). This novel finding, albeit in a small series of patients, may support the theory that transverse force couple imbalance is associated with PSSH.Level of evidenceLevel 4 – Case series with no comparison group.

The Evolution of the Walch Classification for Primary Glenohumeral Arthritis.

Our understanding of the pathology of and treatment for glenohumeral arthritis (GHA) has grown dramatically in the past few decades. Original observations regarding patterns of glenoid erosion, glenoid retroversion, and posterior humeral head subluxation in patients with primary GHA were documented in the 1980s and early 1990s. In the late 1990s, Walch et al proposed what is now the most widely used classification system to describe the characteristic pathology of GHA. Improved understanding of both premorbid and pathologic anatomies, along with advancements in imaging, have steered modifications in this classification system. These changes have improved its reliability and helped to further guide management decisions. The purpose of this article is to review the evolution of the Walch classification, understand the rationale behind the modifications, and discuss potential future developments.

Does the Walch type B shoulder have a transverse force couple imbalance? A volumetric analysis of segmented rotator cuff muscles in osteoarthritic shoulders.

The etiology of the Walch type B shoulder remains unclear. We hypothesized that a scapulohumeral muscle imbalance, due to a disturbed transverse force couple (TFC) between the anterior and posterior rotator cuff muscles, may have a role in the pathogenesis of the type B morphology. The purpose of this study was to determine whether there is a TFC imbalance in the Walch type B shoulder using an imaging-based 3-dimensional (3D) volumetric and fatty infiltration assessment of segmented rotator cuff muscles. Computed tomography images of 33 Walch type A and 60 Walch type B shoulders with the complete scapula and humerus including the distal humeral epicondyles were evaluated. The 3D volumes of the entire subscapularis, supraspinatus, and infraspinatus-teres minor (Infra-Tm) were manually segmented and analyzed. Additionally, anthropometric parameters including glenoid version, glenoid inclination, posterior humeral head subluxation, and humeral torsion were measured. The 3D muscle analysis was then compared with the anthropometric parameters using the Wilcoxon rank sum and Kruskal-Wallis tests. There were no significant differences (P > .200) in muscle volume ratios between the Infra-Tm and the subscapularis in Walch type A (0.93) and type B (0.96) shoulders. The fatty infiltration percentage ratio, however, was significantly greater in type B shoulders (0.94 vs. 0.75, P < .001). The Infra-Tm to subscapularis fatty infiltration percentage ratio was significantly larger in patients with >75% humeral head subluxation than in those with 60%-75% head subluxation (0.97 vs. 0.74, P < .001) and significantly larger in patients with >25° of retroversion than in those with <15° of retroversion (1.10 vs. 0.75, P = .004). The supraspinatus fatty infiltration percentage was significantly lower in Walch type B shoulders than type A shoulders (P = .004). Walch type A shoulders had mean humeral retrotorsion of 22° ± 10° whereas Walch type B shoulders had humeral retrotorsion of only 14° ± 9° relative to the epicondylar axis (P< .001). The TFC is in balance in the Walch type B shoulder in terms of 3D volumetric rotator cuff muscle analysis; however, the posterior rotator cuff does demonstrate increased fatty infiltration. Posterior humeral head subluxation and glenoid retroversion, which are pathognomonic of the Walch type B shoulder, may lead to a disturbance in the length-tension relationship of the posterior rotator cuff, causing fatty infiltration.

Nonoperative Management of Posterior Shoulder Instability: What Are the Long-Term Clinical Outcomes?

To report the injury characteristics, radiographic findings, and long-term outcomes of nonoperative management for posterior shoulder instability (PSI). A retrospective review of 143 patients with PSI using a large geographic database. Single county between January 1994 and July 2012. A clinical history and diagnosis of PSI, one confirmatory imaging study to support the diagnosis, and a minimum of 5 years follow-up were required for inclusion. Patients with seizure disorders, anterior-only instability, multidirectional instability, and superior labrum from anterior to posterior diagnosis were excluded. Patients with PSI were managed nonoperatively or operatively. Pain, recurrent instability, and progression into glenohumeral osteoarthritis at long-term follow-up. One hundred fifteen patients were identified. Thirty-seven (32%) underwent nonoperative management. Twenty (54%) patients were diagnosed with posterior subluxation, 3 (8%) with a single dislocation, and 7 (19%) with multiple dislocations. Symptomatic progression of glenohumeral arthritis was observed in 8% (3) of patients. Pain improved in 46% (17) of patients and worsened in 19% (7). Recurrent instability and progression to osteoarthritis occurred in 15% (3/20) of patients with a traumatic instability event compared with 0% of atraumatic patients after nonoperative management (P = 0.234). Pain at follow-up was more common in nonoperative than operative patients (P = 0.017). Nonoperative management is a viable option for many patients with posterior shoulder instability; however, many may continue to have posterior shoulder pain.

Does non-spherical humeral head with inlay glenoid re-center the glenohumeral joint?

BackgroundTreatment of glenohumeral osteoarthritis (OA) with Walch type B glenoid poses a challenge for orthopedic surgeons. Although various techniques have been described, it is still a major concern in terms of management and long-term results. We hypothesized that total shoulder arthroplasty (TSA) using a combination of non-spherical humeral head resurfacing (HHR) and inlay glenoid replacement would re-center the glenohumeral joint in patients with Walch type B glenoid without surgical correction of glenoid version. MethodsWe retrospectively screened patients who underwent TSA using a combination of non-spherical HHR and inlay glenoid replacement for primary glenohumeral OA with posteriorly subluxated humeral head (HH) (Walch Type B1, B2 and B3) between 2015 and 2019. Ratios of preoperative and postoperative HH subluxation were compared using Walch index and the point of contact ratio method. Two orthopedic surgeons performed radiographic measurements blinded to each other. Means of 2 independent measurements were included in the final analysis for each shoulder. We also screened for postoperative complications, dislocation events and radiographic loosening. ResultsInitial cohort included 49 patients. A total of 29 shoulders in 28 patients were eligible for screening. The numbers of shoulders with Walch type B1, B2, and B3 glenoids were 3, 22, and 4, respectively. Mean preoperative and postoperative Walch indices were 56.57 ± 6.08% and 49.47 ± 4.78%, respectively. The mean preoperative and postoperative point of contact ratios were 62.97 ± 8.45% and 50.08 ± 3.87%, respectively. The difference between preoperative and postoperative subluxation ratios was significant for both methods (P < .01). Inter-rater reliability was found to be good-excellent. The overall complication rate at a mean follow-up period of 37.79 months was 10.34% (3/29). One patient experienced deep vein thrombosis (DVT) (3.22%) on postoperative day 8. Two patients experienced infection (6.45%), one of which required a revision TSA (3.22%) at 19 months after surgery. No patient experienced shoulder dislocation and no loosening was detected on postoperative radiographs. ConclusionWhen coupled with an inlay glenoid component in patients with eccentric glenoid wear and posterior subluxation, glenohumeral re-centering was consistently observed in this challenging patient population without the use of joint correction or augmentation procedures. It will be important to follow the clinical outcomes over the long-term to determine whether these observations translate to better clinical results than other techniques currently employed to deal with eccentric erosion and posterior subluxation of the arthritic glenohumeral joint although recent published mid-term results suggest results equal to or better than previously reported results in literature with different reconstructive techniques Level of evidenceLevel IV; Retrospective cohort

Correction of equinus deformity by means of a new unconstrained ilizarov frame system.

This study aimed to clarify the effectiveness of a novel technique utilizing the new unconstrained Ilizarov frame system by evaluating the clinical outcomes of equinus deformity correction. From January 1998 to December 2012, a total of 9 consecutive patients (median age: 33 years) with equinus deformity were treated by using a simple, unconstrained, hinge-less Ilizarov frame, which was developed to correct talar subluxation using an unconstrained frame system. All patients had equinus deformity >30°, although preoperative radiographs showed a congruous ankle joint with no fixed bony deformity. Preoperative equinus deformity was evaluated as well as dorsal flexion (DF) in Ilizarov at 3 months after removal and at final follow-up. Furthermore, the presence or absence of talar subluxation at the time removal of the Ilizarov apparatus, and whether or not ankle arthrodesis was finally indicated, was evaluated. Median follow-up period was 76 months. Median preoperative equinus deformity was -40° None of the patients showed anterior or posterior subluxation of the talus at the time of removal. Three months after removal of the Ilizarov apparatus, the median DF angle was -5° However, 4 patients showed less than -15° of DF and underwent ankle arthrodesis with the ankle joint in the 5° DF position. At the final follow-up, median DF angle was 5°. This technique allows for safe, gradual correction of equinus deformity without talar subluxation, although additional procedures, such as ankle arthrodesis, may be needed in some cases.

Arthroscopic Posterior Glenoid Reconstruction Using a Fresh Distal Tibia Allograft for Recurrent Posterior Instability

Posterior glenohumeral instability is a relatively uncommon cause of shoulder instability. Recurrent posterior instability with static posterior humeral head subluxation is often associated with critical glenoid bone loss. Unlike anterior instability, the amount of bone loss for posterior instability that requires surgical reconstruction remains a topic of debate. Several techniques have been described to treat critical bony defects in patients with recurrent posterior shoulder instability with the use of both autografts and allografts depending on the amount of bone loss present. Open posterior glenoid bone block procedure is associated with increased risk of complications and morbidity to the patient. As such, all-arthroscopic techniques have emerged with the advantage of allowing for the diagnosis and treatment of concomitant glenohumeral pathology and minimizing soft-tissue dissection through the posterior deltoid and rotator cuff muscles. Reported short-term outcomes of arthroscopic posterior bone block stabilization are promising; however, it remains a technically challenging procedure due to intra-articular graft insertion and subsequent fixation congruent to the posterior glenoid articular margin. We describe an all-arthroscopic technique using a fresh distal tibia allograft fixation using 2 partially threaded screws in conjunction with an arthroscopic Latarjet fixation set for a patient with recurrent posterior shoulder instability and associated glenoid bone loss.

Standard radiological classification of glenohumeral osteoarthritis does not correlate with the complexity of the arthritic glenoid deformity.

The Samilson-Prieto classification (SPC) depending on the humeral osteophyte length on a-pX-rays today is widely used to classify glenohumeral osteoarthritis in general. For treatment planning and prognosis, the patho-morphology of the glenoid and static posterior subluxation of the humeral head classified according to Walch is of much higher importance. Here, usually a CT or MRI scan is required for a correct classification. A possible correlation between both classifications is poorly explored. Without it, the complexity of the case might be mis-interpreted using the SPC. The aim of this study was to investigate such a correlation, i.e. whether it correlates with the glenoid deformity and degree of humeral head subluxation. Radiological datasets (X-ray and CT or MRI) of 352 patients with primary OA of the shoulder were evaluated by two observers experienced in shoulder surgery. For the Samilson-Prieto classification, true a-p shoulder radiographs and for the modified Walch classification CT or MRI scans in the axial plane were interpreted using a validated method. To investigate a correlation between both classifications, the Fisher's exact test was used. For the interobserver reliability, the weighted kappa coefficient κ was determined. For the Walch classification, both observers found a similar percentage for the different types, with decreasing numbers from normal (type A1) to severely altered glenoids In the Samilson-Prieto classification, OA grade I was predominant, while grade II and III showed a relatively equal distribution. Interobserver reliability was high both for the Walch classification with a κ 0.923 (95% confidence interval 0.892; 0.954) and) for the SPC with a κ 0.88 (95% confidence interval 0.843; 0.916). A correlation between the two classifications in Fischer's exact test could not be shown (p = 0.584). Since there is no correlation between both, using the Samilson-Prieto classification alone might miss relevant prognostic factors in gleno-humeral OA. Adequate imaging of the glenoid morphology also in the axial plane is absolutely mandatory to understand the complexity and chose the right treatment for each patient. Study of Diagnostic Test-Level II.

Post-traumatic elbow osteoarthritis after radial head arthroplasty: Prevalence and risk factors

BackgroundOne of the treatment options for comminuted radial head fractures is radial head arthroplasty (RHA), especially when the elbow is also dislocated. While the clinical outcomes of RHA have been well documented, the incidence of post-traumatic osteoarthritis after RHA and its risk factors are not well known. ObjectiveTo determine the incidence of post-traumatic elbow osteoarthritis (humeroulnar and humeroradial joints) after RHA and identify its risk factors. MethodsAll patients who underwent RHA at our hospital between 2008 and 2016 were included retrospectively. The inclusion criteria were primary RHA, recent radial head fracture (isolated or associated with elbow dislocation), minimum 1 year of follow-up, clinical and radiographic examination at final assessment. The exclusion criteria were pre-existing elbow osteoarthritis, RHA revision, multiple fractures of the ipsilateral upper limb or polytrauma. The final assessment consisted of a clinical examination [joint range of motion (ROM) and Mayo Elbow Performance Score (MEPS)] and standard radiographs. The correlation between the incidence and severity of osteoarthritis and various risk factors was determined. ResultsSeventy-three patients were included in the analysis with a mean age of 56 years (21–85). The injuries consisted of 41 terrible triad, 15 isolated radial head fractures, 11 Monteggia fractures and 6 transolecranon fracture-dislocations. The mean follow-up was 3.4 years (1–10.9). At the final assessment, osteoarthritis was visible in the humeroulnar compartment in 56% of cases and in the humeroradial compartment in 72% of cases. There was a statistical correlation between the presence of humeroulnar osteoarthritis at the final assessment and ROM in flexion-extension (p=0.003), MEPS (p<0.001), duration of immobilization (p=0.03) and presence of posterior subluxation on immediate postoperative radiographs (p=0.012). The correlation between humeroradial osteoarthritis at the final assessment and ROM in flexion-extension (p=0.0054), RHA implant position (p<0.01), and unipolar configuration (p=0.027) was statistically significant. ConclusionIn our study, elbow osteoarthritis incidence after RHA was 56% in the humeroulnar joint and 72% in the humeroradial joint. RHA implant placement, posterior subluxation immediately postoperative and the duration of immobilization were significantly corelated with osteoarthritis. Level of evidenceIV; case series without control group.

Similar scapular morphology in patients with dynamic and static posterior shoulder instability.

BackgroundThere is evidence that specific variants of scapular morphology are associated with dynamic and static posterior shoulder instability. To this date, observations regarding glenoid and/or acromial variants were analyzed independently, with two-dimensional imaging or without comparison with a healthy control group. Therefore, the purpose of this study was to analyze and describe the three-dimensional (3D) shape of the scapula in healthy and in shoulders with static or dynamic posterior instability using 3D surface models and 3D measurement methods.MethodsIn this study, 30 patients with unidirectional posterior instability and 20 patients with static posterior humeral head subluxation (static posterior instability, Walch B1) were analyzed. Both cohorts were compared with a control group of 40 patients with stable, centered shoulders and without any clinical symptoms. 3D surface models were obtained through segmentation of computed tomography images and 3D measurements were performed for glenoid (version and inclination) and acromion (tilt, coverage, height).ResultsOverall, the scapulae of patients with dynamic and static instability differed only marginally among themselves. Compared with the control group, the glenoid was 2.5° (P = .032), respectively, 5.7° (P = .001) more retroverted and 2.9° (P = .025), respectively, 3.7° (P = .014) more downward tilted in dynamic, respectively, static instability. The acromial roof of dynamic instability was significantly higher and on average 6.2° (P = .007) less posterior covering with an increased posterior acromial height of +4.8mm (P = .001). The acromial roof of static instability was on average 4.8° (P = .041) more externally rotated (axial tilt), 7.3° (P = .004) flatter (sagittal tilt), 8.3° (P = .001) less posterior covered with an increased posterior acromial height of +5.8 mm (0.001).ConclusionThe scapula of shoulders with dynamic and static posterior instability is characterized by an increased glenoid retroversion and an acromion that is shorter posterolaterally, higher, and more horizontal in the sagittal plane. All these deviations from the normal scapula values were more pronounced in static posterior instability.

Evaluation of cervical spine injury and predicting neurological deficit by magnetic resonance imaging

Background: The consequences of cervical spine injuries range from simple neck pain, to quadriplegia, or even death. MR imaging has become part of the diagnostic and prognostic tools for spinal cord injury. Aim: To prospectively evaluate cervical spine injuries by MR imaging and to find out association of MR imaging findings with degree of neurological deficit. Material and Methods: Descriptive longitudinal hospital based study was conducted on 30 patients with known or suspected cervical spine trauma who presented to the emergency department. Results: Mean age of the cases was about 42 years, with female to male ratio of 1:6.5. C6-C7 spinal level was most commonly involved. Proportions complete spinal cord injury (CSCI), incomplete spinal cord injury (ISCI) and neurologically normal (NN) were 23.33%, 60% and 16.67% respectively. Out of 12 MRI findings, cord haemorrhage, contusion, posterior element fracture, disc injury, prevertebral hematoma, subluxation and soft tissue injury was statistically associated with degree of neurological deficit. Cord contusion, cord haemorrhage and posterior element fracture were potential predictors of neurological status at admission. Cord contusion, cord haemorrhage and subluxation were potential predictors at 3 months. Conclusion: MRI proved a pivotal role in the diagnosis of SCIs, deciding prompt management and predicting neurological deficit and prognosis of neurological recovery. So, MRI is an excellent diagnostic modality for the evaluation of spinal trauma and predicting the degree of neurological deficit and recovery.

Inestabilidad Posterior de Hombro. Revisión de conceptos actuales

Chronic posterior glenohumeral instability presents recurrent posterior subluxation that is characterized by pain rather than a sensation of instability. However, if it is accompanied by other instabilities such as the previous or lower one, we would be facing a different scenario known as multidirectional instability. Although posterior shoulder instability is a rare pathology compared to anterior instability, there is an increasing amount of research and literature on the subject, which has led specialists to improve the knowledge and understanding of the mechanism and pathophysiology of this entity.Evidence Level: IV

Limb lengthening of a rare case of congenital femoral deficiency with an unstable knee

Congenital femoral deficiency (CFD) is a rare birth defect that is characterized by a short femur, associated with hip and knee deformity, deficiency, or instability. Children with severe CFD may need multiple deformity correction or lengthening procedures to reduce axial malalignment and limb length discrepancy (LLD). During limb lengthening, it can occur knee subluxation or dislocation, a severe treatment-related complication. We report a 15-year-old girl with a CFD with a previous episode of posterior subluxation of the knee during a femoral lengthening using a monolateral external fixator. She had a 13 cm LLD and coxa vara; therefore, it was applied a knee spanning Ilizarov fixator with a double osteotomy of the femur for gradual correction. At 11 months following Ilizarov application, a complete correction was achieved, and the circular fixator was removed. Knee joints of patients with CFD show highly variable grades of instability. Adequate surgical techniques, preventive measures, and early detection of signs of subluxation can lead to good functional results. Femur lengthening with a preventive bridging of the knee with an Ilizarov frame is a safe and effective way of treating patients with CFD.

Restoration of the Posterior Glenoid in Recurrent Posterior Shoulder Instability Using an Arthroscopically Placed Iliac Crest Bone Graft: A Computed Tomography-Based Analysis.

Background:Posterior shoulder instability is uncommon, and its treatment is a challenging problem. An arthroscopically assisted technique for posterior iliac crest bone grafting (ICBG) has shown promising short- and long-term clinical results. Changes as shown on imaging scans after posterior ICBG for posterior shoulder instability have not been investigated in the recent literature.Purpose:To evaluate changes on computed tomography (CT) after arthroscopically assisted posterior ICBG and to assess clinical outcomes.Study Design:Case series; Level of evidence, 4.Methods:Patients with preoperative CT scans and at least 2 postoperative CT scans with a minimum follow-up of 2 years were included in the evaluation. Of 49 initial patients, 17 (follow-up rate, 35%) met the inclusion criteria and were available for follow-up. We measured the glenoid version angle and the glenohumeral and scapulohumeral indices on the preoperative CT scans and compared them with measurements on the postoperative CT scans. Postoperatively, graft surface, resorption, and defect coverage were measured and compared with those at early follow-up (within 16 months) and final follow-up (mean ± SD, 6.6 ± 2.8 years).Results:The mean preoperative glenoid version was –17° ± 13.5°, which was corrected to –9.9° ± 11.9° at final follow-up (P < .001). The humeral head was able to be recentered and reached normal values as indicated by the glenohumeral index (51.8% ± 6%; P = .042) and scapulohumeral index (59.6% ± 10.2%; P < .001) at final follow-up. Graft surface area decreased over the follow-up period, from 24% ± 9% of the glenoid surface at early follow-up to 17% ± 10% at final follow-up (P < .001). All clinical outcome scores had improved significantly. Progression of osteoarthritis was observed in 47% of the shoulders.Conclusion:Arthroscopically assisted posterior ICBG restored reliable parameters as shown on CT scans, especially glenoid version and the posterior subluxation indices. Graft resorption was common and could be observed in all shoulders. Patient-reported clinical outcome scores were improved. Osteoarthritis progression in almost 50% of patients is concerning for the long-term success of this procedure.

Scapulothoracic Alignment Alterations in Patients with Walch Type B Osteoarthritis: An In Vivo Dynamic Analysis and Prospective Comparative Study.

Background: Kinematic changes of the scapulothoracic joint may influence the relative position of the glenoid fossa and, consequently, the glenohumeral joint. As the alignment of the scapula relative to the thorax differs between individuals, such variability may be another factor in the development of posterior head subluxation. The purpose of this study was to compare scapulothoracic alignment in pathologic type B shoulders with contralateral healthy shoulders. Methods: Seven adult volunteers with unilateral type B glenohumeral osteoarthritis (OA) underwent bilateral computed tomography (CT) scans of the shoulders and arms. A patient-specific, three-dimensional measurement technique that coupled medical imaging (i.e., CT) and optical motion capture was used. Results: The scapulothoracic distance at the trigonum was 75 ± 15 mm for pathologic shoulders and 78 ± 11 mm for healthy shoulders (p = 0.583), while at the inferior angle, it was 102 ± 18 mm for pathologic shoulders and 108 ± 12 mm for healthy shoulders (p = 0.466). Conclusion: Scapula positioning at a resting position did not differ between pathologic and healthy shoulders. However, pathologic shoulders tended to be limited in maximal glenohumeral motion and exhibited greater anterior tilt of the scapula in internal rotation at 90 degrees, which may be adaptive to the restricted glenohumeral motion.

Incidence of Posterior Shoulder Instability in the United States Military: Demographic Considerations From a High-Risk Population

Background: Relatively little is known about the true incidence of posterior shoulder instability in the United States. Purpose/Hypothesis: The purpose of this study was to characterize the incidence of posterior shoulder instability in the US military population and to examine which characteristics place these patients at highest risk. We hypothesized that the rate of posterior instability in this cohort of patients would be higher than previously reported. Study Design: Descriptive epidemiology study. Methods: All initial cases of posterior shoulder dislocation and subluxation in the Defense Medical Epidemiology Database were screened between 2016 and 2018 using the relevant International Classification of Diseases–Tenth Revision-Clinical Modification codes. Incidences were calculated, and multivariate Poisson regression was used to calculate adjusted rate ratios for the effects of sex, race, age, military service branch, rank, and year. Results: The overall unadjusted incidence was 0.032 per 1000 person-years for posterior dislocations, 0.064 per 1000 person-years for posterior subluxations, and 0.096 per 1000 person-years for all cases of posterior shoulder instability. The total incidence of all shoulder instability was 1.84 per 1000 person-years, with posterior shoulder instability accounting for 5.2% of total cases. For posterior subluxation, significant differences between groups were found in the unadjusted and adjusted rate ratio (ARR) for sex (ARR, 3.31; 95% CI, 1.85-5.93 for men), race (ARR, 0.458; 95% CI, 0.294-0.714 for Black servicemembers and ARR, 0.632; 95% CI, 0.421-0.948 for servicemembers of other race), age (ARR, 3.69; 95% CI, 1.56-8.70 for patients aged 30-34 years), and military service branch (ARR, 0.663; 95% CI, 0.460-0.955 for Air Force servicemembers). For posterior shoulder dislocations, a significant difference was found only between men and women (ARR, 4.55; 95% CI, 1.85-11.2 for men). Conclusion: The incidence of posterior shoulder instability among US military personnel is higher than previously reported in the general US population, with a majority of cases due to subluxation. This increased incidence is likely reflective of a young and highly active population along with improvements in awareness and diagnosis of posterior instability in recent years.

Return to Sport After Arthroscopic Treatment of Posterior Shoulder Instability.

Background:Arthroscopic treatment of posterior shoulder instability has become more popular and effective in recent years, but few data are available concerning the rate of return to sport.Purpose:To present our experiences with arthroscopic posterior labral reconstruction in athletes and review our results, with a particular focus on the rate of return to sport.Study Design:Case series; Level of evidence, 4.Methods:Included in the study were 40 arthroscopic stabilizations performed because of posterior shoulder instability in 37 athletes at a single institution. During follow-up, the athletes’ rate of return to sport was calculated. Shoulder function was evaluated based on a pre- versus postoperative comparison of the Rowe instability score and the American Shoulder and Elbow Surgeons score. Additionally, the return-to-sport rate was compared among different subgroups: traumatic versus atraumatic origin of injury, competitive versus recreational athletes, high-risk versus low-risk sport, and posterior-only versus anterior and posterior stabilization. Data were statistically analyzed using paired-samples t test and nonparametric Fisher exact test.Results:The average follow-up period was 54.4 months (range, 24-112 months). Three shoulders (7.5%) continued to have posterior subluxations postoperatively. There were 34 excellent, 3 good, and 3 fair results based on the Rowe score (average postoperative score, 92.9), and patients achieved an average postoperative American Shoulder and Elbow Surgeons score of 92.7. The pre- to postoperative improvement was statistically significant in both scoring systems (P < .001). Of the 37 patients, 36 (98.2%) were able to return to sport activity: 27 of them (72.9%) to their original sport and 19 (51.4%) at their preinjury level. A significantly higher rate of return to the same sport occurred in athletes who had traumatic injury compared with a subgroup of athletes without a traumatic event (P < .02).Conclusion:More than half of the athletes were able to return to their preinjury level of sport after arthroscopic posterior labral reconstruction. In addition, low recurrence rates and good functional outcomes were seen in >90% of the patients, and 98% returned to sport activity. The athletes had a significantly higher rate of return to sport if their posterior shoulder instability had a clear traumatic origin.

Telescopic rod technique to reverse anterior subluxation of the talus during the correction of equinocavovarus deformity with the Ilizarov fixator

Anterior subluxation of the talus (AST) can occur during the correction of equinocavovarus using Ilizarov external fixation, which should be reduced under anaesthesia and fixed by Ilizarov external fixation. The ankle joint has multi-directional dynamic rotational axis, so it is difficult to find the correct ankle rotational axis during external fixation, even for experienced doctors. The objective of this study is to describe a telescopic rod (T-rods) technique that allows AST to be reversed without anaesthesia during the correction of an equinovarus deformity with the Ilizarov external fixation. In patients with equinocavovarus foot deformity, corrective procedures including bone and soft tissue procedures were performed first, and then the Ilizarov fixator was applied. Correction of the deformity was started immediately after relief of pain and oedema in the foot and ankle. The Ilizarov apparatus was manipulated to apply gradual, controlled distraction as tolerated. If AST was found on the postoperative radiographs during correction by the Ilizarov apparatus, T-rods were installed immediately without anaesthesia to reverse AST. Generally, after the T-rods were installed, the correction of AST is started. The anterior rod (A-rod) was shortened to cause ankle dorsiflexion. The T-rods were extended so that the talus would move backward slowly and return to the ankle joint, and the T-rods rotated forward at the same time. As a result, the talus was restored, and the equinocavovarus deformity was corrected. In the course of correction, the reduction of AST was confirmed by taking radiographs. Once AST was completely reduced, T-rods extension was stopped to prevent posterior subluxation of the talus due to excessive traction. Telescopic rods are effective for reversing AST during correction of equinovarus with an Ilizarov fixator. Moreover, telescopic rods may be used routinely for all patients to avoid AST. AST can occur during the correction of equinocavovarus using Ilizarov external fixation. We describe a telescopic rod technique that allows AST to be reversed without anaesthesia during the correction of an equinovarus deformity with the Ilizarov fixator. This may guide surgeons to provide new perspectives and ideas in preventing AST and may support to design more targeted therapies to reduce AST.

Fracture Dislocation of the Knee - A Staged Approach for Bony and Ligamentous injuries or All-at-Once Surgery?

HISTORY - 45yo male sustained a closed right knee injury after crashing his all-terrain vehicle. In the emergency department, his examination showed and isolated deformity to his right knee. He had intact motor nerve function to the right leg but complained of numbness to the distribution of the common peroneal nerve. He had strong peripheral pulses with an ABI 1.0. X-rays and CT (Figure 1, Figure 2) revealed a comminuted displaced anteromedial tibial plateau fracture, altered tibiofemoral alignment with posteromedial tibia subluxation and a fibular head fracture. MRI examination (Figure 3) added the presence of a medial meniscal root detachment and PCL rupture. Figure 2Coronal, sagittal and axial CT imaging demonstrating a comminuted displaced anteromedial tibial plateau fracture with posterior subluxation of the tibia View Large Image Figure Viewer Download Hi-res image Figure 3A. Coronal images of the right knee demonstrating a medial meniscal root tear/detachment with displacement (white arrow), a fibular head fracture with intact biceps, LCL, peroneal fascia (bent arrow). B. Rupture of femoral sided PCL with posterior tibial subluxation (white arrow). C. Lateral compartment posterior tibial subluxation with tenting of the popliteal tendon. View Large Image Figure Viewer Download Hi-res image