Increase In External Rotation Research Articles

Population-based in silico modeling of anatomical shape variation of the knee and its impact on joint loading in knee osteoarthritis.

Anatomical knee joint features and osteoarthritis (OA) severity are associated, however confirming causals link to altered knee loading is challenging. This study leverages statistical shape models (SSM) to investigate the relationship between joint shape/alignment and knee loading during gait in knee OA(KOA) patients to understand their contribution to elevated medial knee loading in OA. Musculoskeletal (MSK) models were created for the mean as well as the first eightSSM principal modes of variation (-3,-2,-1, +1, +2, +3 standard deviations for each mode) and used as input to a MSK modeling framework. Using an identical KOA gait pattern (i.e., joint kinematics and ground reaction forces), we ran simulations for each MSK model and evaluated medial compartment loading magnitude and contact distribution at the instant of first and second peak of knee joint loading. An increase in external rotation, posterior tibia translation and a decrease in medial joint space and medial femoral condylar size predisposed the medial compartment knee joint to overloading during gait. This was coupled with an anterior and medial shift in contact location with increasing external rotated tibial position and increasing posterior tibial translation with respect to the femur. Next, results also highlighted a posterior shift of the medial compartment loading location with decreasing medial joint space. This study provides important population-based insights on how knee shape and alignment predispose individuals with KOA to elevated medial compartmental knee loading. This information can be crucial in assessing the risk for medial KOA development and progression.

Shoulder kinetic during pitching in baseball players with scapular dyskinesis

IntroductionShoulder injuries in baseball players cause excessive shoulder load during pitching and scapular dyskinesis (SD). However, the characteristics of pitching kinetics in the shoulder joint with SD are unclear. This study aimed to investigate the effect of SD on pitching kinetics in the shoulder joint of baseball players. MethodSeventy-two college and independent league baseball players participated in the study. The pitching motion was measured using an 18–camera motion-capture system. SD was classified into four types (I–IV) using the scapular dyskinesis test (SDT). The pitching kinetics data were analyzed. ResultsThe agreement of SD in this study was 56/72 (77.8%). SD were classified into 31 abnormal group (type I–Ⅲ) and 25 control group (type Ⅳ). Three participants with measurement failure during the pitching motion analysis were excluded from the analysis. The abnormal group showed a larger maximum value of the glenohumeral normalized anterior joint force than the control group. ConclusionsThese results suggest that an increase in GH anterior force during pitching causes an excessive increase in external rotation of the GH with an insufficient posterior tilt of the scapula with SD. Therefore, baseball pitching with SD may involve shoulder injuries owing to excessive shoulder load during pitching.

The effect of medial only versus medial and lateral hamstring lengthening on transverse gait parameters in cerebral palsy.

Benefits of hamstring lengthening surgery on the sagittal plane in children with cerebral palsy have been previously demonstrated, but there is limited information on its effects on the transverse plane. This study compared the effects of medial hamstring lengthening (MHL) with those of medial and lateral hamstring lengthening (MLHL) procedures in the transverse plane. Children with gross motor function classification system (GMFCS) levels I-III who had MHL or MLHL were included. Baseline, short- (1-2 years), and long-term (3+ years) postoperative three-dimensional gait analysis outcomes were compared using analysis of variance. Children were excluded if they had concurrent osteotomies or tendon transfers. One hundred fifty children (235 limbs) were included, with 110 limbs in the MHL group (age 8.5 ± 4.1 years, GMFCS I-27%, II-52%, and III-21%) and 125 limbs in the MLHL group (age 10.0 ± 4.0 years, GMFCS I-23%, II-41%, and III-37%). Time between surgery and short- and long-term follow-up gait analysis was 1.5 ± 0.6 years and 6.6 ± 2.9 years, respectively. Transmalleolar axis became more external after MHL at both short and long terms ( P < 0.05), whereas there were only significant differences at long term in MLHL ( P < 0.05). Although hamstring lengthening has a positive impact on stance phase knee extension in children with cerebral palsy, intact lateral hamstrings after MHL likely contribute to increased tibial external rotation after surgery. Significant increases in external rotation at the knee in the long term are likely related to a trend present with growth in children with cerebral palsy rather than a direct result of surgical intervention.

Functional Femoral Anteversion: Axial Rotation of the Femur and its Implications for Stem Version Targets in Total Hip Arthroplasty.

BackgroundAcetabular and femoral component positioning are important considerations in reducing adverse outcomes after total hip arthroplasty (THA). Previous assessments of femoral anteversion examined anatomic femoral anteversion (AFA) referenced to anatomic landmarks. However, this does not provide a functional understanding of the femur’s relationship to the hip. We investigate a new measurement, functional femoral anteversion (FFA), and sought to measure its variability across a large sample of patients undergoing THA.MethodsA total of 1008 consecutive patients underwent THA surgery between September 2019 and July 2021. All patients were measured for supine and standing functional femoral rotation (FFR), AFA, and FFA.ResultsThe mean standing FFA was 13.2° ± 12.2° (−27.8° to 52.3°). The mean change in FFR from supine to standing was −2.2° ± 11.8° (−43.0° to 41.9°). Of all, 161 (16%) patients had standing FFA version greater than 25°. Four hundred sixty (46%) patients had standing FFR (internal or external) greater than 10°. One hundred twenty-three (12%) patients exhibited an increase in external rotation from supine to standing of greater than 10°. A moderate, negative linear relationship was observed between AFA and standing external femoral rotation (P <<.001, R = −0.46), indicating people may externally rotate their femur as AFA decreases with age.ConclusionsFunctional alignment of the femur in patients requiring THA is understudied. It is now understood that the femur, like the pelvis, can rotate substantially between functional positions. Enhancing our understanding of FFA and FFR may improve both acetabular and femoral component positioning.

Impact of Capsulotomy on Hip Biomechanics during Arthroscopy.

Background and Objectives: Anterior capsulotomy is routinely performed in hip arthroscopy to improve joint visualization; however, this can partly or completely disrupt the stabilizing ligaments of the hip. This study aimed to report the effects of conventional and extensive arthroscopic capsulotomies on hip stability. Materials and Methods: Eight freshly frozen cadaveric pelvises were used in this study. The range of motion and translation were measured and compared among different capsular conditions utilized in hip arthroscopy, with a special interest in the iliofemoral ligament (IFL) and zona orbicularis (ZO). The conditions included intact capsule, interportal capsulotomy, T-capsulotomy, complete IFL disruption, and complete IFL and ZO disruption. Internal rotation at three flexion planes (−10°, 0°, and 30°) and external rotation at six flexion planes (−10°, 0°, 30°, 60°, 90°, and 110°) were measured with corresponding femoral head translation distance at the application of 2.5 Nm torque. Results: As compared to an intact capsule, a significant increase in external rotation was observed after interportal capsulotomy from −10° to 60° and after T-capsulotomy from −10° to 110° flexion. A significant translation was observed only with a T-capsulotomy, which ranged from 1.9 to 2.3 mm across the flexion angles. Compared with conventional interportal capsulotomy, disruption of the entire IFL resulted in a significant increase in external rotation in all flexion planes, and significant translation was accompanied by disruption of the ZO. Conclusions: Interportal capsulotomy can result in an increase in range of motion, and T-capsulotomy can lead to significant translation. Partial or complete tears of the IFL and ZO can result in further external rotation and translation.

Biomechanical Comparison of Capsular Repair, Capsular Shift, and Capsular Plication for Hip Capsular Closure: Is a Single Repair Technique Best for All?

Background:In hip arthroscopy, the best capsular closure technique to prevent microinstability in some patients while preventing overconstraints in other patients has yet to be determined.Purpose:To evaluate the biomechanical effects of capsular repair, capsular shift, and combination capsular shift and capsular plication for closure of the hip capsule.Study Design:Controlled laboratory study.Methods:Eight cadaveric hips (4 male and 4 female hips; mean age, 55.7 years) were evaluated in 7 conditions: intact, vented, capsulotomy, side-to-side repair, side-to-side repair with capsular plication (interval closure between iliofemoral and ischiofemoral ligaments), capsular shift repair, and capsular shift repair with plication. Measurements, via a 360° goniometer, included internal and external rotation with 1.5 N·m of torque at 5° of extension and 0°, 30°, 60°, and 90° of flexion. In addition, the degree of maximum extension with 5 N·m of torque and the amount of femoral distraction with 40 N and 80 N of force were obtained. Repeated-measures analysis of variance and Tukey post hoc analyses were used to analyze differences between capsular conditions.Results:At lower hip positions (5° of extension, 0° and 30° of flexion), there was a significant increase in external rotation and total rotation after capsulotomy versus the intact state (P < .05). At all hip flexion angles, there was a significant increase in external rotation, internal rotation, and total rotation as well as a significant increase in maximum extension after capsulotomy versus capsular shift with plication (P < .05 for all). At all flexion angles, both capsular closure with side-to-side repair (with or without plication) and capsular shift without capsular plication were able to restore rotation, with no significant differences compared with the intact capsule (P > .05). Among repair constructs, there were significant differences in range of motion between side-to-side repair and combined capsular shift with plication (P < .05).Conclusion:At all positions, significantly increased rotational motion was seen after capsulotomy. Capsular closure was able to restore rotation similar to an intact capsule. Combined capsular shift and plication may provide more restrained rotation for conditions of hip microinstability but may overconstrain hips without laxity.Clinical Relevance:More advanced closure techniques or a combination of techniques may be needed for patients with hip laxity and microinstability. At the same time, simple repair may suffice for patients without these conditions.

Superior Capsule Reconstruction for Irreparable Massive Rotator Cuff Tears: Does It Make Sense? A Systematic Review of Early Clinical Evidence

Background: Treatment of irreparable massive rotator cuff tears (MRCTs) in patients without advanced glenohumeral osteoarthritis remains a challenge. Arthroscopic superior capsule reconstruction (SCR) represents a newer method for treatment with increasing popularity and acceptance. Purpose: To analyze the clinical evidence surrounding SCR and determine the current clinical outcomes postoperatively. Study Design: Systematic review. Methods: A systematic review of the literature was performed following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Electronic databases of PubMed, MEDLINE, Cochrane, and Google Scholar were used for the literature search. The study quality was evaluated according to the Modified Coleman Methodology Score. Studies in English evaluating SCR outcomes were included. Results: Seven studies were reviewed, including 352 patients (358 shoulders) treated with arthroscopic SCR with the mean duration of follow-up ranging from 15 to 48 months (range, 12-88 months). Fourteen patients were lost to follow-up, leaving 338 patients (344 shoulders) with clinical outcome data. Graft types included dermal allografts (n = 3 studies), fascia lata autografts (n = 3), or both (n = 1). Most commonly, a double-row technique was utilized for humeral graft fixation. The most common complication included graft tears in 13% of patients, resulting in 15 SCR revisions and 7 reverse shoulder arthroplasties. Postoperatively, improvements in visual analog scale (2.5 to 5.9), American Shoulder and Elbow Surgeons (20 to 56), Japanese Orthopaedic Association (38.0), Subjective Shoulder Value (37.0 to 41.3), and Constant (11.6 to 47.4) scores were observed. Three studies reported respective satisfaction rates of 72.9%, 85.7% and 90%. Increases in external rotation, internal rotation, and abduction with improved strength in external rotation were observed postoperatively. Improvement of pseudoparalysis was also observed in 3 studies. One study reported return to sports in 100% of patients (2 competitively, 24 recreationally) with no adverse outcomes. Conclusion: SCR showed good to excellent short-term clinical outcomes with adequate pain relief and functional improvement. The current evidence suggests that the procedure is an alternative for symptomatic patients with irreparable MRCT; however, the included studies were fair to poor in quality, and there were some notable complications. Long-term follow-up will determine the longevity and ultimate role of this new method in the treatment of irreparable MRCT.

Changes in Alignment of Ipsilateral Knee on Computed Tomography after Total Hip Arthroplasty for Developmental Dysplasia of the Hip.

ObjectiveTo assess the changes in alignment of ipsilateral knee joint after total hip arthroplasty (THA) for patients with developmental dysplasia of the hip (DDH).MethodsThirty‐four patients with DDH (38 hips) who underwent THA between February and December 2008 were included in the study: 4 men and 30 women with a mean age of 56.2 years. According to Crowe classification, 11 patients were grade I, 12 were grade II, 9 were grade III, and 6 were grade IV. Computed tomography scans were performed from the anterior superior iliac spine to the tibial tubercle before surgery and at last follow‐up. Femoral anteversion angle, leg lengthening, and knee alignment, including patellar tilt angle, lateral patellar displacement, and tibiofemoral rotation angle, were measured on computed tomography scans, and their relationships were analyzed.ResultsThe mean follow‐up period was 51.5 months (range, 39–70 months). There were no intraoperative fractures, and no infections occurred during the follow‐up period. One patient developed deep venous thrombosis and another suffered from femoral nerve palsy. The mean preoperative Harris Hip Score was 48.9 ± 7.5 and improved to 91.2 ± 8.3 by the last follow‐up (P < 0.001). There was no sign of prosthetic loosening in all hips. Postoperatively, mean leg lengthening was 26.08 ± 21.81 mm (P < 0.001), femoral anteversion decreased 9.03° ± 12.80° (P < 0.001), and patellar tilt, lateral patellar displacement, and tibiofemoral rotation increased by 3.58° ± 4.96° (P < 0.001), 1.78 ± 3.36 mm (P = 0.002), and 2.56° ± 3.37° (P < 0.001), respectively. Postoperative increase in patellar tilt and lateral patellar displacement had significant linear relationships with the decrease in femoral anteversion (r = 0.621, P < 0.001 and r = 0.437, P = 0.0037, respectively). These results revealed that patellofemoral alignment would change more with the decrease in femoral anteversion. Postoperative increase in external rotation of the tibia had significant positive linear relationships with leg lengthening (r = 0.34, P = 0.037) and the decrease in femoral anteversion (r = 0.693, P < 0.001). These results revealed that the external rotation of the proximal tibia would increase with the leg lengthening or the decrease of femoral anteversion. Postoperative changes in patellar tilt and lateral patellar displacement had no significant linear relationships with leg lengthening (P = 0.795 and P = 0.082, respectively).ConclusionsTotal hip arthroplasty for DDH could induce changes in alignment of ipsilateral patellofemoral and tibiofemoral joints, with increases in patellar tilt and displacement, and increases in external rotation of the tibia. These secondary alterations still existed at medium‐term follow‐up after surgery, which should be considered during THA for patients with DDH. Extended follow‐up is necessary to evaluate long‐term changes in the knee joint.

The effect of torsional moments on the posterolateral rotatory stability of a lateral ligament deficient elbow: An in vitro biomechanical investigation

BackgroundClinical tests for posterolateral rotatory instability of the elbow apply external torsional moments to the forearm; however, biomechanical studies of lateral collateral ligament injuries and their surgical repair, reconstruction and rehabilitation have primarily relied on varus gravity loading to quantify instability.The aim of this investigation was to determine the effect of torsional moments on the posterolateral rotatory instability of the lateral ligament deficient elbow. MethodsSix cadaveric arms were tested in an elbow motion simulator with the arm in the varus position. A threaded outrigger was inserted on the dorsal aspect of the proximal ulna to suspend 400 g, 600 g, and 800 g of weight to allow torsional moments of 0.12, 0.18, and 0.23 Nm respectively on the ulna. An injured model was created by sectioning of the common extensor origin, and the lateral collateral ligament. FindingsDuring simulated active flexion with the arm in varus, the injured model resulted in a significant increase in external rotation of the ulnohumeral articulation with the forearm both pronated and supinated (pronation: P = .021; supination: P = .015). The application of torsional moments to the lateral ligament deficient elbow resulted in a significant increase in the posterolateral rotatory instability of the elbow. InterpretationThis investigation demonstrates that the application of even small amounts of external torsional moments on the forearm with the arm in the varus position increases the rotational instability of the lateral ligament deficient elbow. During clinical examination for posterolateral rotatory instability and biomechanical studies of lateral ligament injury, the application of external torsion to the forearm should be considered to detect subtle instability. Level of evidenceBasic Science Study.

Coronal tibial alignment is linked to femoral rotational asymmetry: Implications for total knee arthroplasty surgery

BackgroundFemoral rotational asymmetry (FRA) is the difference in rotational alignment between the trochlear groove and posterior condyles. We hypothesize that FRA increases as the tibial plateau becomes more varus due to internal rotation of the posterior condyles and external rotation of the trochlear groove to ensure a vertical trochlear groove at 90o knee flexion. MethodsSeventy lower limb Computed Tomography (CT) scans were reviewed by two examiners. Comparisons were made between both the sulcus line (SL) and posterior condylar line (PCL) relative to the surgical epicondylar axis (SEA). Femoral and tibial coronal alignment were measured on CT scanograms and 3D reconstructions. Correlation analysis was performed to identify associations between FRA, SL and PCL and the coronal alignment of the tibia and femur. ResultsThe mean FRA was +2.9° (SL externally rotated to PCL) (−2.4° to +7.7°, SD 2.2o). FRA greater than four degrees occurred in (17/70) 24% of knees. A statistically significant correlation was found between the degree of FRA and proximal tibial varus (MPTA) (R2 = 0.67, p < 0.001). Furthermore, there were significant correlations between the SL and the MPTA (p < 0.001, R2 = 0.77) and the PCL and the MPTA (p < 0.001, R2 = −0.41). ConclusionNative femora are frequently rotationally asymmetrical. As the tibial plateau becomes increasingly varus there is an increase in external rotation of the SL and internal rotation of the PCL. The effect is to maintain a more vertical trochlear groove during flexion in the presence of a varus tibia.

Capsular plication in the non-deformity hip: impact on post-operative joint stability

Purpose and hypothesisThe aim of this study was to evaluate the hip joint range of motion after different capsular plication. The study hypothesis proposed that capsular plication after hip arthroscopy may reduce hip external rotation and thus prevent the hip joint instability created by arthroscopic capsulotomies.MethodsSix fresh frozen human cadavers were studied in the intact state (5 males, 1 females) for a total of 12 non-deformity hips tested. They were fixed to the operating room table using a custom-made apparatus. Three Steinman pins were inserted, the first into ASIS, a parallel pin into the distal femur proximal to inter-epicondylar axis and the third pin into the lateral epicondyle. Simulation of arthroscopic capsulotomies was done progressively with simulation of three capsular plication techniques. The first plication technique consisted of a primary plication shift of the antero-lateral capsule. The distal-medial arm of the iliofemoral ligament was shifted toward the proximal-lateral arm. The second plication technique consisted in adding a longitudinal arm to the capsulotomy, between the lateral arm and the medial arm of the iliofemoral ligament, to create a T-shaped capsulotomy. The resulting two triangular capsular flaps were overlaid onto each other by approximately 5 mm, plicated fully and tighly sutured in a double-breast manner. The third plication technique, called redrapping, consisted in excising the inferior capsular triangular flap (previously made in the second technique), and suturing the latero-anterior superior capsular flap to the medial arm of the iliofemoral ligament, superimposing the capsular edges for closure. External rotation of the hip at 0°, 15° and 30° of flexion were obtained after the capsulotomy and each capsular plication technique to quantify the increase in hip stability after plication. Data were assessed using a two-way repeated measure analysis of variance (ANOVAs) and Student’s T-test when necessary to determine if the change in external rotation was significantly different.ResultsAfter capsulotomy, external rotation averaged 26.3°, 29.1° and 31.1° at 0°, 15° and 30° of flexion. With the primary plication shift, external rotation averaged 24.9°, 30.3° and 34.0°. With the two-triangle technique, external rotation averaged 26.1°, 31.9° and 33.3°. With the re-draping technique, external rotation averaged 25.8°, 30.9° and 32.0°. A significant relationship was found between «Plication Technique» and «Angle of flexion» factors for the measured angle of external rotation (P = 0.04).A decomposition of the interaction showed that external rotation decreased at 0° of hip flexion and increased as the hip flexion angle increased. The only significant difference found corresponded to the two triangles technique at 15° flexion (mean difference compared to the non-repaired state = 2.8° ± 3.8° or 8.8% increase in external rotation; P = 0.03).ConclusionsDifferent techniques of capsular plication result in a non-significant increase in hip external rotation when compared to unrepaired capsulotomies. Therefore, special attention should be paid at the time of capsular plication, which could be disadvantageous when done overzealously aiming to increase postoperative stability.

Prospective Study on Physiological Intorsion of Lower Limbs in Children

Background: Rotational profiles vary widely among healthy children. Rotation of the long bones refers to the twist of the bone about its long axis. Rotational deformity of the lower limb in the transverse plane is associated with many clinical settings ranging from harmless to excessive intoeing in children. Materials and Methods: This study was conducted at the Department of Orthopedics, Indraprastha Apollo Hospital, New Delhi. Children presenting to the outpatient department during the period of April to September 2013 were followed up. It is a prospective study conducted over 14 months. A total of 27 children (54 lower limbs) were included and followed up. Results: Twenty-seven children were selected as per the inclusion criteria and assessed for the thigh-transmalleolar axis, thigh-foot angle, femoral anteversion (FA), foot progression angles (FPA), and hip rotations at 4-month interval for 2 follow-ups. There were very few studies of such type which have been conducted in India. Conclusions: In our study, there was a definite and significant decrease in FPA and internal tibial torsion with increasing age. The values of clinical anteversion also decreased with age along with a gradual decrease of internal rotation and an increase of external rotation (ER). The decrease of FA with age correlated better with increase of hip ER. FPA was a significant clinical parameter which gave us an objective picture of the change in both femoral and tibial torsions with age.

Biomechanical influence of deficient posterolateral corner structures on knee joint kinematics: A computational study.

The posterolateral corner (PLC) structures including the popliteofibular ligament (PFL), popliteus tendon (PT) and lateral collateral ligament (LCL) are important soft tissues for posterior translational, external rotational, and varus angulation knee joint instabilities. The purpose of this study was to determine the effects of deficient PLC structures on the kinematics of the knee joint under gait and squat loading conditions. We developed subject-specific computational models with full 12-degree-of-freedom tibiofemoral and patellofemoral joints for four male subjects and one female subject. The subject-specific knee joint models were validated with computationally predicted muscle activation, electromyography data, and experimental data from previous study. According to our results, deficiency of the PFL did not significantly influence knee joint kinematics compared to an intact model under gait loading conditions. Compared with an intact model under gait and squat loading conditions, deficiency of the PT led to significant increases in external rotation and posterior translation, while LCL deficiency increased varus angulation. Deficiency of all PLC structures led to the greatest increases in external rotation, varus angulation, and posterior translation. These results suggest that the PT is an important structure for external rotation and posterior translation, while the LCL is important for varus angulation under dynamic loading conditions. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-8, 2018.

Contribution of the Ligamentum Teres to Hip Stability in the Presence of an Intact Capsule: A Cadaveric Study

To determine the contribution of the ligamentum teres (LT) to hip stability in the presence of an intact capsule with special attention to the change in range of motion and femoral head translation. Seven fresh-frozen cadaveric pelvises were used. Following visual inspection of the LT at different hip positions, internal rotation angles were measured at 10° of extension and at 0° of flexion, while external rotation was measured at 60°, 90°, and 110° of flexion with different hip abduction angles using electromagnetic motion tracking sensor. Femoral head translations were measured simultaneously. The tests were repeated after resection of the LT. The capsule was left intact for all test conditions. The results were compared between intact and LT resected conditions when torque of 2 and 4Nm was applied. Compared with the intact hip, the LT resected hip showed no significant difference when 2Nm torque was applied in all scenarios. With 4 Nm torque application, significant increase in external rotation was found at 60° and at 90° of flexion (1.7° ± 0.8° and 2.1° ± 1.0°, respectively). Significant difference was also noted at 60°, 90°, and 110° of flexion when the hip was in the adducted position while at 90° in the abducted hip. However, LT resection did not show significant change in internal rotation. There was no significant difference in the translation distance of the femoral head in the intact hip compared with the LT resected hip (0.77-1.11mm vs 0.79-1.29mm). Our results indicate that within the physiologic range of motion, LT can minimally limit external rotation when the hip is in the flexed position but does not contribute to translation stability. In the hip with intact capsule, LT deficiency can result in a slight increase in range of motion, but its contribution to stability is questionable.

The influence of anatomic total shoulder arthroplasty using a subscapularis tenotomy on shoulder strength

There is limited evidence describing the influence of total shoulder arthroplasty on strength. The hypothesis was that after total shoulder arthroplasty, strength would improve compared with the preoperative state but remain inferior to that of the nonoperative shoulder. An additional aim was to determine whether strength improvement was associated with improvements in outcome scores and motion. Thirty-six patients underwent total shoulder arthroplasty, with 31 patients (86%) having 1 year of follow-up for all outcomes. Patient-determined outcomes (Western Ontario Osteoarthritis of the Shoulder score; Disabilities of the Arm, Shoulder and Hand score; Single Assessment Numeric Evaluation rating; and shoulder activity level), range of motion, and strength were assessed. Isometric strength was determined for scaption and external rotation, as well as the liftoff test, belly-press test, and bear-hug test. All strength measures improved, with significant increases in external rotation, the liftoff test, and the bear-hug test, but remained inferior to the nonoperative-side strength. Improved strength in the belly-press test was associated with greater improvement in Single Assessment Numeric Evaluation scores. Improvements in scaption and belly-press testing were associated with improvements in active flexion. Strength improvements in the liftoff test were associated with improved internal rotation in 90° of abduction. Patients with improvements in strength had improvements in their shoulder activity level from baseline to final follow-up, whereas patients without improved strength test findings did not have improved shoulder activity levels. Total shoulder arthroplasty improved external rotation, liftoff, and bear-hug strength testing. Operative shoulder strength remained inferior to strength of the nonoperative shoulder. Patients with improvements in strength were more likely to have greater improvements in outcome scores and range of motion. Improvements in the shoulder activity level after anatomic total shoulder arthroplasty may be dependent on improvements in strength.

Glenosphere size in reverse shoulder arthroplasty: is larger better for external rotation and abduction strength?

The role of glenosphere size in reverse shoulder arthroplasty (RSA) may be important in prosthetic stability, joint kinematics, rotator cuff tension and excursion, scapular impingement, humeral lateralization, deltoid wrap, and the occurrence of "notching." This study compared short- and midterm clinical and radiographic outcomes for 2 different glenosphere sizes of a single RSA type with respect to implant positioning, glenoid size, and morphology. This retrospective analysis included 68 RSA procedures that were prospectively documented in a local register during a 5-year postoperative period. Two glenosphere diameter sizes of 36 mm (n = 33) and 44 mm (n = 35) were used. Standard radiographs were made preoperatively (ie, baseline) and at 6, 12, 24, and 60 months after surgery. Range of motion, strength, the Constant-Murley score, and the Shoulder Pain and Disability Index were also assessed at all follow-up visits. The effect of glenosphere size on measured outcomes was adjusted for baseline values, patient gender, and humeral head diameter. No significant differences were found in the functional scores between treatment groups at all follow-up assessments. At the 12-month follow-up, patients with a 44-mm glenosphere had greater external rotation in adduction (mean difference, 12°; P = .001) and abduction strength (mean difference, 1.4 kg; P = .026) compared with those with the smaller implant. These differences remained at 60 months. Scapular notching was observed in 38% of all patients, without any relevant difference between the groups. An increase in glenosphere diameter leads to a clinically moderate but significant increase in external rotation in adduction and abduction strength at midterm follow-up.

Internal and External Rotation Stabilizers of the Knee with Intact Cruciate and Collateral Ligaments

Objectives:The purpose of this study was to assess the effect of sequentially cutting the posterolateral, anterolateral, posteromedial and anteromedial structures of the knee on rotational kinematics in the setting of intact cruciate and collateral ligaments. It was hypothesized that cutting of the iliotibial band (ITB), anterolateral ligament and lateral capsule (ALL/LC), the posterior oblique ligament (POL), and the posteromedial capsule (PMC) would significantly increase internal rotation and that the anteromedial capsule (AMC), and the popliteus tendon and popliteofibular ligament (PLT/PFL) when sectioned would lead to a significant increase in external rotation of the knee.Methods:Ten pairs (n = 20) of cadaveric knees were assigned to two sequential cutting groups (posterolateral-to-posteromedial and posteromedial-to-posterolateral). Specimen were subjected to 5 N-m of internal and external rotation torque at knee flexion angles 0° through 90° in the intact and after each cut state. Rotational changes were measured and compared to the intact and previous states following each cut.Results:Sectioning of the ITB significantly increased internal rotation at 60° and 90° by 5.4° and 6.2[[Unsupported Character - Codename ­]]°, respectively (after ALL/LC cut) and 3.5° and 3.8° (prior to ALL/LC cut) (Figure 1). At 60° and 90°, section of the ALL/LC produced significant increases in internal rotation of 3.1[[Unsupported Character - Codename ­]]° and 3.5°, respectively (after ITB cut) and of 0.5° (prior to ITB cut) (Figure 1). At 0°, section of the POL produced significant increases in internal rotation of 2.0° (ITB intact) and 1.8° (after ITB cut) (Figure 1). Sectioning the PLT/PFL complex significantly increased external rotation at 60° and 90° by 2.7° and 2.9°, respectively (prior to sectioning medial structures) and 2.2° and 2.7[[Unsupported Character - Codename ­]]°, respectively (after sectioning medial structures) (Figure 2). Sectioning the AMC produced significant increases in external rotation at 30°- 90° of flexion, however the magnitude of change was < 1° (Figure 2).Figure 1.Changes in internal rotation from the intact state during a 5 N-m internal rotation torque when sequentially cutting structures from lateral to medial (above) and medial to lateral (below).Figure 2.Changes in external rotation from the intact state during a 5 N-m external rotation torque when sequentially cutting structures from lateral to medial (above) and medial to lateral (below).Conclusion:Collectively the anterolateral corner structures had a primary role in internal rotational control of the knee from 60° to 90° of knee flexion. The ITB was the most significant primary stabilizer for internal rotation in ACL intact knees. The POL contributed to internal rotational control at full extension, while the PLT/PFL complex controlled external rotation of the knee at higher flexion angles (60° and 90°). Internal rotation control of the knee has been mainly attributed to the cruciate and collateral ligaments. This study delineates the primary and secondary roles of the ITB, the ALL/LC, POL and PLT/PFL to rotatory stability of the knee. As such, it provides new information about the understanding of rotational instabilities of the knee.

Rotational glenohumeral adaptations are associated with shoulder pathology in professional male handball players.

Glenohumeral range of motion adaptations may affect throwing athletes and contribute to shoulder injury. The purpose of this study was to evaluate shoulder rotation deficits among elite professional handball players and its correlation to the presence of shoulder pain and morphological changes. Eighty-seven elite professional handball players and 41 healthy non-athlete volunteers participated in the study. Evaluations included measurement of range of internal and external rotation, total arch of motion, identification of shoulder pain and ultrasound scan for diagnosis of rotator cuff tears and internal impingement. Glenohumeral rotational deficits (>20-25°) were found among 11 players group (13%). The throwing shoulders in the players group showed a decrease in internal rotation and an increase in external rotation with significantly larger ranges among players compared to the non-athlete group. Internal rotation deficit >20° was associated with higher incidence of shoulder pain among players. Both internal rotation deficits (>25°) and total arch of motion deficit (>20°) co-existed with higher incidence of internal impingement. Shoulder pain was common (36/97-41%) and was associated with decreased external rotation and total arch of motion. Internal impingement (found in 13/87-15%) correlated with decreased rotation ranges and a greater deficit in total arch of motion, whereas higher gain in external rotation correlated with a partial rotator cuff tear (found in 12/87-14%). Shoulder pathologies and problems commonly affected the group of handball players. Greater glenohumeral rotational deficits in throwing shoulders of handball players correlate with shoulder pain and internal impingement, while increased external rotation with partial rotator cuff tears. Such deficits affect 13% of the athlete population. Major clinical relevance of the study is to monitor handball players' shoulders both clinically and by proper imaging. Evaluation of range of rotation seems to identify shoulders at risk of the pathology. Cross-Sectional study with control group, Level II.

Effect of Humeral Component Version on Outcomes in Reverse Shoulder Arthroplasty.

Although reverse shoulder arthroplasty provides excellent clinical results in appropriately selected patients, loss of external and internal rotation may occur. Component selection, design, and placement affect postoperative results. Recent studies considered the effect of humeral component version on functional results. The current study investigated whether humeral stem retroversion affects the outcomes of reverse shoulder arthroplasty with a retrospective review of a multisurgeon, industry-sponsored, prospectively gathered database of a single reverse shoulder arthroplasty implant. All patients had at least 2-year follow-up. Clinical outcomes, including American Shoulder and Elbow Surgeons score, visual analog scale pain score, Short Form-12 Mental and Physical Component scores, range of motion, and internal rotation function, were compared between patients with humeral retroversion of 10° or less (group A) and those with humeral retroversion of 20° or greater (group B). Radiographic outcomes were compared. The analysis included 64 patients (group A, 29 patients; group B, 35 patients). No clinical or statistically significant difference was found in American Shoulder and Elbow Surgeons scores. Both groups showed statistical and clinical improvement vs preoperative scores, with group A averaging 77.8 and group B averaging 79.2 at final follow-up. No differences were found between groups in range of motion or ability to perform tasks that require shoulder internal rotation. Patients can expect good clinical improvement after reverse shoulder arthroplasty. No difference was found in clinical or radiologic outcomes based on humeral component retroversion. Despite the theoretical increase in external rotation when the humeral component is placed closer to native retroversion, the results did not show this effect. [Orthopedics. 2017; 40(3):179-186.].

MRI Quantification of the Impact of Ankle Position on Syndesmosis Anatomy.

Despite the common occurrence of syndesmotic injuries in ankle trauma, the distal tibiofibular relationship remains poorly understood. The aim of this study was to evaluate the anatomical impact of ankle sagittal positioning on the tibiofibular relationship in intact ankles by using a validated magnetic resonance imaging (MRI)-based measurement system. In this radiologic study, 34 healthy volunteers underwent a series of ankle MRIs with the ankle stabilized in 3 positions: neutral position (NP), dorsiflexion (DF), and plantarflexion (PF). Using a previously validated measurement system, 6 fixed translational measurements and 2 fixed angles were recorded on each MRI and compared using paired t tests. When comparing PF to DF, the anterior distance between the tibial incisura and the fibula varied from 2.5 mm to 3.9 mm ( P < .001), respectively. The middle distance between the tibial incisura and the fibula varied from 1.5 mm to 2.6 mm ( P < .001). Fibular angle varied from 8.7 degrees to 7.8 degrees of internal rotation ( P = .046), respectively. When comparing NP to DF, only the anterior distance was found to be significantly different, varying 0.4 mm ( P < .002). Ankle dorsiflexion leads to an increase in external rotation and lateral translation of the fibula. These changes could be measured on MRI using a validated measurement system. Ankle motion did have an impact on the distal tibiofibular relationship and should be considered in studies pertaining to syndesmosis imaging. This is the first in vivo study demonstrating the impact of sagittal ankle position on the distal tibiofibular relationship in an uninjured ankle. Our findings also support the practice of placing the ankle in dorsiflexion when fixing a disrupted syndesmosis. Level III, comparative study.