Abduction Angle Research Articles

Influence of obesity and intra-operative imaging guidance technology on acetabular cup positioning in total hip arthroplasty.

Accuracy of acetabular cup positioning during total hip arthroplasty (THA) can be improved with intra-operative imaging but may be influenced by body mass index (BMI). This study assessed the influence of BMI (kg/m2) on cup accuracy when using intra-operative fluoroscopy (IF) alone or supplemented with a commercial product. This retrospective review included four consecutive cohorts of patients having undergone anterior approach THA with IF alone (2011-2015), IF and Overlay (2015-2016) (Radlink Inc., Los Angeles, CA), IF and Grid (2017-2018) (HipGrid Drone™, OrthoGrid Systems Inc., Salt Lake City, UT) and IF and Digital (2018-2020) (OrthoGrid Phantom®, OrthoGrid Systems, Inc., Salt Lake City, UT). Component placement accuracy was measured on 6-week post-operative weight bearing radiographs and compared between four BMI patient groups (BMI ≤ 25, 25 < BMI ≤ 30, 30 < BMI ≤ 35, and 35 < BMI). Total fluoroscopy times were also recorded directly from the fluoroscopy unit. Abduction angle significantly increased as BMI increased (p = 0.003) with IF alone but no difference was present in groups with guidance technology. Anteversion was significantly different between BMI groups for IF alone (p = 0.028) and Grid (p = 0.027) but was not different in Overlay (p = 0.107) or Digital (p = 0.210). Fluoroscopy time was significantly different between BMI categories for IF alone (p = 0.005) and Grid (p = 0.018) but was not different in Overlay (p = 0.444) or Digital (p = 0.170). Morbid obesity (BMI > 35) increases risk for malpositioning of acetabular cups and increases surgical time with IF alone or the Grid. Additional IF guidance technology (Overlay or Digital) increased cup positioning accuracy without decreasing surgical efficiency.

Effect of reverse shoulder arthroplasty humeral component retroversion on acromial strain.

Acromion and scapular spine stress fractures can be catastrophic complications following reverse shoulder arthroplasty (RSA). A variety of host, implant, and technical factors have been identified that increase the risk of this complication. The glenoid component in particular has been closely evaluated for its impact on rates of stress fractures following RSA. The goal of this biomechanical study is to evaluate if humeral stem version has an impact on acromion and scapular spine strain after RSA. Eight cadaveric specimens were tested on a custom dynamic shoulder frame. Commercially available RSA components were implanted with the humeral component inserted in 0° of retroversion. Acromion and scapular spine strain were measured at 0°, 30°, and 60° of abduction using strain rosettes secured to the acromion and scapular spine in the typical locations for Levy type II and type III stress fractures, respectively. The humeral stem was then removed and reimplanted in 30° of retroversion and the measurements were repeated. Student t test was performed to analyze the relationship between humeral stem version and acromion and scapular spine strain at various abduction angles. Strain at the both the acromion and scapular spine were found to have no significant difference at any abduction angle when comparing 0° and 30° version of the humeral stem. With 0° and 30° versions pooled together, there is significantly lower acromion and scapular spine strain at 60° of abduction when compared to 0° of abduction (strain at 0° abduction - strain at 60° abduction: acromion 313.1 μꜪ; P=.0409, Scapular spine 304.9 μꜪ; P=.0407). There was no significant difference in strain at either location when comparing 0° of abduction to 30° of abduction and when comparing 30° of abduction to 60° of abduction. This biomechanical study found no significant difference in scapular spine and acromion strain after RSA when comparing variations in humeral stem version. There does appear to be lower strain at both the acromion and scapular spine at 60° of abduction when compared to 0° of abduction regardless of stem version.

Effect of Whole Body Parameters on Knee Joint Biomechanics: Implications for ACL Injury Prevention During Single-Leg Landings

Background: Previous studies have examined the effect of whole body (WB) parameters on anterior cruciate ligament (ACL) strain and loads, as well as knee joint kinetics and kinematics. However, articular cartilage damage occurs in relation to ACL failure, and the effect of WB parameters on ACL strain and articular cartilage biomechanics during dynamic tasks is unclear. Purposes: (1) To investigate the effect of WB parameters on ACL strain, as well as articular cartilage stress and contact force, during a single-leg cross drop (SLCD) and single-leg drop (SLD). (2) To identify WB parameters predictive of high ACL strain during these tasks. Study Design: Descriptive laboratory study. Methods: Three-dimensional motion analysis data from 14 physically active men and women were recorded during an SLCD and SLD. OpenSim was used to obtain their kinematics, kinetics, and muscle forces for the WB model. Using these data in kinetically driven finite element simulations of the knee joint produced outputs of ACL strains and articular cartilage stresses and contact forces. Spearman correlation coefficients were used to assess relationships between WB parameters and ACL strain and cartilage biomechanics. Moreover, receiver operating characteristic curve analyses and multivariate binary logistic regressions were used to find the WB parameters that could discriminate high from low ACL strain trials. Results: Correlations showed that more lumbar rotation away from the stance limb at peak ACL strain had the strongest overall association (ρ = 0.877) with peak ACL strain. Higher knee anterior shear force (ρ = 0.895) and lower gluteus maximus muscle force (ρ = 0.89) at peak ACL strain demonstrated the strongest associations with peak articular cartilage stress or contact force in ≥1 of the analyzed tasks. The regression model that used muscle forces to predict high ACL strain trials during the dominant limb SLD yielded the highest accuracy (93.5%), sensitivity (0.881), and specificity (0.952) among all regression models. Conclusion: WB parameters that were most consistently associated with and predictive of high ACL strain and poor articular cartilage biomechanics during the SLCD and SLD tasks included greater knee abduction angle at initial contact and higher anterior shear force at peak ACL strain, as well as lower gracilis, gluteus maximus, and medial gastrocnemius muscle forces. Clinical relevance: Knowledge of which landing postures create a high risk for ACL or cartilage injury may help reduce injuries in athletes by avoiding those postures and practicing the tasks with reduced high-risk motions, as well as by strengthening the muscles that protect the knee during single-leg landings.

The Extensor Digiti Quinty (EDQ) Opponensplasty—Revisited

Introduction: The extensor digiti quinty (EDQ) opponensplasty, although previously described, is not widely used by hand surgeons. This tendon transfer was used selectively in cases of combined median-ulnar nerve palsies at our center over the last 4 years, with the primary goal to preserve the extensor indices proprius (EIP) for pinch plasty. We present our technique and the series of 8 patients that underwent EDQ opponensplasty here. Materials and Methods: A retrospective chart review identified patients with combined median-ulnar nerve palsies that underwent EDQ opponensplasty between 2015 and 2019 at our institution by a single surgeon. Primary outcome measures collected were pinch, grip, disabilities of the arm, shoulder, and hand (DASH) scores, thumb position, palmar abduction angle, and thumb span. Secondary outcomes included donor site morbidity and complications. Results: Eight patients (9 hands) ages 21 to 53 underwent EDQ opponensplasty, with an average follow-up of 8 months. Postoperative pinch and grip on the affected side improved from preoperative values. All 9 transfers were functional with the thumb positioned in the palmar plane of the hand. Palmar abduction ranged from 45 to 70 degrees. Motor reeducation was achieved without any difficulty in all patients. No patients had evidence of donor site morbidity. Discussion: The EDQ opponensplasty is satisfactory in achieving thumb opposition in the setting of combined median-ulnar neuropathy, without evidence of donor site morbidity. The EDQ is expendable, has adequate length, an optimal line of pull, minimal donor site morbidity, and leaves the extensor indices proprius available for pinch plasty.

Percutaneous steroid injection versus oral NSAIDs on treatment of symptomatic calcific rotator cuff tendinitis: a short-term retrospective clinical evaluation

Aim: Symptomatic calcific rotator cuff tendinopathies (CRCT) continue to be a significant health problem in the adult population because of intense pain and disability. Different clinical responses obtained with different treatment modalities show us the importance of determining the optimal method. The aim of this study is to compare short term pain and functional status improvements in adult patients diagnosed with CRCT and treated with oral non-steroid anti-inflammatory drugs (O-NSAID) or percutaneous steroid injections (PSI).&#x0D; Material and Method: A retrospective examination was made of the clinical results of adult patients diagnosed with CRCT and treated with one of the two treatment methods. Whole study group was formed of 40 patients (20 male, 20 female) with a mean age of 42.35 ± 8.28 (range, 23-57) years. The clinical responses of the patients in a period of 3 months were compared between the two treatment groups O-NSAID, PSI using the Visual Analogue Scale (VAS) and the Quick Disability of the Arm, Shoulder, and Hand Scale (Q-DASH). The angular upper limit values of the active range of motion (ROM) of the shoulder joint (anteflexion and abduction angle) of patients also were compared in the study. &#x0D; Results: In the PSI treatment group, in the 3rd week and 3rd month clinical evaluations, significant better responses were obtained in both the VAS and Q-DASH scores of the patients compared to O-NSAID treatment group (p=0.000, p=0.001, respectively). And significant greater shoulder anteflexion and abduction ROM upper limits were determined in the PSI treament group compared to O-NSAID treatment group at the end of the 3rd month (p=0.000, p=0.000, respectively).&#x0D; Conclusion: The percutaneous steroid applications in treatment of CRCT can provide more pleasing short term results than O-NSAID treatments in terms of pain reduction and functional improvement.

Effect Of Different Grip Position And Shoulder- Abduction Angle On Muscle Strength And Activation During The Seated Cable Row

The purpose of this study was to compare the peak force and electromyographic activation in different techniques of the seated row. Eleven recreationally trained male (28±5 years, 176±5 cm, 94±16 kg) and ten female (27±5 years, 168±8 cm, 65±11 kg ) performed an isometric and a dynamic assessment of the seated cable row and the preacher curl: pronated grip (PRO), supinated grip (SUP), neutral grip (NEU), 30° (30°), 60° (60°), 90° (90°) of shoulder abduction, and cable preacher curl (PC). Peak force and muscle activation of upper trapezius, middle trapezius, upper latissimus, lower latissimus, posterior deltoid, and biceps bracii were recorded during the isometric and dynamic assessment of the exercises. p values&lt;0.05 were considered statistically significant. The peak force was greater when shoulder abduction angle was closer to 0° (PRO, SUP, and NEU) and decreased as abduction angle increased (60° and 90°). Muscle activation of the upper back (upper trapezius, middle trapezius) and posterior deltoid increased as abduction angle increased (60° and 90°) on both isometric and dynamic analysis. Muscle activation of the upper and lower latissimus increased as abduction angle was closer to 0° (PRO, SUP, and NEU) on both isometric and dynamic analysis. Biceps brachii activation on both isometric and dynamic analysis during the PC was greater than all other rowing conditions; among the rowing techniques, BB activation was greater during SUP, NEU, and 90° techniques. In conclusion, the closer to 90° shoulder abduction the greater UT, MT, and PD activity, on the other hand, the closer to 0° shoulder abduction the greater peak force, UL, and LL activity during the variations of the rowing exercise.

Lower Limb Biomechanics during the Golf Downswing in Individuals with and without a History of Knee Joint Injury.

Although prevention is better than treatment, after a knee injury occurs, the adjustment of the movement technique back to the posture before the injury and the restoration of accuracy is very important for professional and amateur players. This study aimed to compare the differences in lower limb mechanics during the golf downswing between those with and without a history of knee joint injury. A total of 20 professional golfers with single-digit handicaps were recruited for this study, 10 of whom had a knee injury history (KIH+), while another 10 players were without a knee injury history (KIH-). From the 3D analysis, selected kinematic and kinetic parameters during the downswing were analyzed using an independent samples t-test with a significance level of α = 0.05. During the downswing, individuals with KIH+ exhibited a smaller hip flexion angle, smaller ankle abduction angle, and larger ankle adduction/abduction range of motion (ROM). Moreover, there was no significant difference found in the knee joint moment. Athletes with a history of knee injury can adjust the motion angles of their hip and ankle joints (e.g., by avoiding excessive forward leaning of the trunk and maintaining stable foot posture without inward or outward rotation) to minimize the impact of changes in their movement patterns resulting from the injury.

Mental Fatigue Uniquely Influences Drop Landing Biomechanics for Individuals With a Concussion History.

Induced mental fatigue negatively impacts sport performance and neurocognition. However, it is unclear how induced mental fatigue influences landing biomechanics. The purpose of this study was to examine the influence of mental fatigue on drop landing biomechanics in individuals with and without a concussion history. Crossover design. Forty-eight (24 per group) recreationally active individuals were matched on age (±3y), sex, and body mass index (±1kg/m2). All participants completed an experimental (30-min Stroop task) and control (30-min reading magazines) intervention on separate days separated by a minimum of 24 hours. Drop landings were performed before and after both interventions. Outcomes included peak vertical ground reaction force (vGRF), vertical loading rate (VLR), knee flexion angle, knee abduction angle, external knee flexion moment, external knee abduction moment, and initial ground contact knee flexion and knee abduction angles. Separate 2 (group) × 2 (intervention) between-within analyses of covariance compared drop landing outcomes. Each group's average pre-Stroop and premagazine outcomes were covariates. There was a significant interaction for vGRF (P = .033, ηp2=.097) and VLR (P = .0497, ηp2=.083). The vGRF simple effects were not statistically significantly (P range = .052-.325). However, individuals with a concussion history displayed a medium effect size for greater vGRF post-Stroop compared with their own postmagazine vGRF (mean difference (95% confidence interval [95% CI] = 0.163 (-0.002 to 0.327) bodyweight (BW), p = .052, ηp2=.081. In contrast, the control group displayed a small effect size (mean difference [95% CI] = 0.095 [-0.069 to 0.259] BW, p = .251, ηp2=.029). Individuals with a concussion history displayed greater VLR post-Stroop compared with controls (mean difference [95% CI], 26.29 [6.19 to 46.40] BW/s, P = .012, ηp2=.134) and their own postmagazine values (mean difference [95% CI] = 32.61 [7.80 to 57.42] BW/s, p = .011, ηp2=.135). Mental fatigue leads to greater VLR for individuals with a concussion history. Athletic competition and activities of daily living can increase mental fatigue. Training programs may seek to teach mental fatigue reducing strategies to athletes with a concussion history.

Hip abduction angle after open-wedge high tibial osteotomy is associated with the timed up & go test and recurrence of varus alignment

The aim of this study is to investigate the association between the hip abduction angle (HAA) and lower limb alignment as well as the clinical assessments in open-wedge high tibial osteotomy (OWHTO) patients. A total of 90 patients who underwent OWHTO were included. The demographic characteristics and clinical assessments (the Visual Analogue Scale for activities of daily living, the Japanese knee osteoarthritis measure, the Knee injury and Osteoarthritis Outcome Score, the Knee Society score, the Timed Up & Go (TUG) test, the single standing (SLS) test and muscle strength) were recorded. The patients were divided into two groups according to the HAA at 1 month after operation: the HAA (−) group (HAA < 0°) and the HAA (+) group (HAA ≥ 0°). Clinical scores except for the SLS test and radiographic parameters except for the posterior tibia slope (PTS), lateral distal femoral angle (LDFA) and lateral distal tibial angle (LDTA) were significantly improved at 2 years postoperatively. Regarding the two groups, scores on the TUG test in the HAA (−) group were significantly lower than those in the HAA (+) group (p = 0.011). The hip-knee-ankle angle (HKA), weight bearing line (WBLR) and knee joint line obliquity (KJLO) in the HAA (−) group were significantly higher than those in the HAA (+) group (p < 0.001, 0.001 and p = 0.025). In contrast, the LDFA in the HAA (−) group were significantly lower than those in the HAA (+) group (p < 0.001). The TUG test and the LDFA were weakly positively correlated with the HAA (r = 0.34, 0.42, p < 0.001 and 0.001). In contrast, the HKA, WBLR and KJLO had a weak negative correlation with the HAA (r = − 0.43, − 0.38 and − 0.37, p < 0.001, 0.001 and 0.001). This study showed the postoperative HAA was significantly associated with the TUG test and the HKA, WBLR, LDFA, and KJLO. A higher postoperative HAA might induce varus recurrence and poor outcomes of the gait parameter.

Ultrasound assessment of the inferior glenohumeral capsule in normal shoulders—a study of measurement variables and reliability

To establish the reliability of a standardised ultrasound protocol to measure normal inferior glenohumeral capsule (IGHC) thickness and to investigate the effects of age, sex, hand dominance and angles of abduction on the thickness. IGHC images were obtained at 60o, 90o and 180o abduction angles of 151 asymptomatic shoulders in supine position. Following the proposed guidelines, three sonographers blindly measured the IGHC thicknesses for intra- and interrater reliability assessments. The intrarater reliability was excellent (intraclass correlation coefficient value = 0.95; 95% CI = 0.92-0.97). The interrater reliability was moderate (intraclass correlation coefficient value = 0.74; 95% CI = 0.60-0.83). The mean IGHC thickness values in mm ± SD at 60o, 90o and 180o abduction angles for males were 3.3 ± 0.93, 3.0 ± 0.80 and 2.6 ± 0.55 and those for females were 2.7 ± 0.86, 2.4 ± 0.7 and 2.0 ± 0.56 respectively. Although males had thicker IGHC, the rate at which the thickness reduced with increased abduction was same in both males and females. Age and hand dominance had no effect. The normal IGHC thickness varies with sex and the abduction angle of the arm at which it is measured. A large variation of IGHC thickness exists in the normal population. The results of this study discourage the use of a single value of IGHC thickness and emphasise the importance of comparing the thickness of the symptomatic side to that of the asymptomatic side of the same subject at the same abduction level. The guidelines provided in this study can be used in clinical practice and in future research studies.

Biomechanical comparison of combined latissimus dorsi and teres major tendon transfer vs. latissimus dorsi tendon transfer in shoulders with irreparable anterosuperior rotator cuff tears.

Irreparable anterosuperior rotator cuff tears (IASRCTs) can result in a gradual loss of active elevation and internal rotation, superior and anterior translation of the humeral head, and cuff tear arthropathy. Joint-preserving treatment options for IASRCTs in young and high-demand elderly patients remain a subject of ongoing debate. The aim of the study was to evaluate the biomechanical efficacy of the combined latissimus dorsi and teres major tendon (LDTM) transfer and compare it to an isolated latissimus dorsi (LD) transfer in a cadaveric IASRCT model. Eight cadaveric shoulders (mean age, 68.3±5.2 years; range 58-71) were tested with a custom shoulder testing system. All specimens were tested at 0°, 30°, and 60° of glenohumeral abduction in the scapular plane under 4 conditions: (1) intact, (2) IASRCT, (3) combined LDTM transfer, and (4) isolated LD transfer. The superior and anteroinferior translation and subacromial contact pressure were measured. The effects of 3 different LD and LDTM muscle loading conditions were investigated to determine the effectiveness of the muscle transfer conditions. A linear mixed effect model was used for statistical analysis, followed by a Tukey post hoc test. IASRCTs significantly increased superior translation, anteroinferior translation, and subacromial peak contact pressure. Combined LDTM transfer significantly decreased superior and anteroinferior translation compared with IASRCTs in all positions and muscle loadings. Isolated LD transfer did not significantly decrease superior (P>.115) and anteroinferior translation (P>.151) compared to IASRCT at any abduction and muscle loads except superior translation at 60° abduction and 90° of external rotation (ER) (P<.036). LDTM transfer also significantly decreased peak contact pressure from the IASRCT condition at every abduction angle (P<.046). However, isolated LD transfer significantly decreased subacromial peak contact pressure only at 30° abduction and 0° and 30° of ER with triple loading (P<.048), as well as at 60° abduction and 90° of ER (P<.003). Combined LDTM transfer decreased superior translation, anteroinferior translation, and subacromial contact pressure compared with the IASRCT condition. Isolated LD transfer did not improve glenohumeral translation and subacromial contact pressure. Combined LDTM transfer may be a more reliable treatment option than isolated LD transfer in patients with an IASRCT.

Comparison of the early clinical efficacy of the SuperPath approach versus the modified Hardinge approach in total hip arthroplasty for femoral neck fractures in elderly patients: a randomized controlled trial

PurposeTo investigate the clinical efficacy and advantages of the SuperPath approach for total hip arthroplasty in the treatment of femoral neck fractures in the elderly population.MethodsFrom February 2018 to March 2019, 120 patients were randomly divided into two groups with 60 patients each: the SuperPath group and the conventional group. The results evaluated included the general operation situation, serum markers, blood loss, pain score, hip function and prosthesis location analysis.ResultsThere was no demographic difference between the two groups. Compared with the conventional group, the SuperPath group had a shorter operation time (78.4 vs. 93.0 min, p = 0.000), a smaller incision length (5.8 vs. 12.5 cm, p = 0.000), less intraoperative blood loss (121.5 vs. 178.8 ml, p = 0.000), a shorter hospitalization time (8.0 vs. 10.8 days, p = 0.000) and less drainage volume (77.8 vs. 141.2 ml, p = 0.000). The creatine kinase level in the SuperPath group was significantly lower than that in the conventional group, while there was no difference in the C-reactive protein level and erythrocyte sedimentation rate level. The visual analog scale score was lower one month postoperatively, and the Harris hip score was higher three months postoperatively in the SuperPath group (p < 0.05). There was no difference in the cup abduction angle or anteversion angle of the two groups.ConclusionWe found better clinical efficacy after using the SuperPath approach with less muscle damage, less postoperative pain and better postoperative function than after using the modified Hardinge approach.Trial registration The randomized clinical trial was retrospectively registered at the Chinese Clinical Trial Registry on 31/12/2020 (ChiCTR-2000041583, http://www.chictr.org.cn/showproj.aspx?proj=57008).

Elliptical and spherical heads show similar obligate glenohumeral translation during axial rotation in total shoulder arthroplasty

BackgroundElliptical shape humeral head prostheses have been recently proposed to reflect a more anatomic shoulder replacement. However, its effect on obligate glenohumeral translation during axial rotation compared to a standard spherical head is still not well understood. The purpose of the study was to compare obligate humeral translation during axial rotation using spherical and elliptical shaped humeral head prostheses. It was hypothesized that the spherical head design would show significantly more obligate translation when compared to the elliptical design.MethodsSix fresh-frozen cadaveric shoulders were utilized for biomechanical testing of internal (IR) and external (ER) rotation at various levels of abduction (0°, 30°, 45°, 60°) with lines of pull along each of the rotator cuff muscles. Each specimen underwent the following three conditions: (1) native; total shoulder arthroplasty (TSA) using (2) an elliptical and (3) spherical humeral head implant. Obligate translation during IR and ER was quantified using a 3-dimensional digitizer. The radius of curvature of the superoinferior and anteroposterior dimensions of the implants was calculated across each condition.ResultsPosterior and inferior translation as well as compound motion of spherical and elliptical heads during ER was similar at all abduction angles (P > 0.05, respectively). Compared to the native humeral head, both implants demonstrated significantly decreased posterior translation at 45° (elliptical: P = 0.003; spherical: P = 0.004) and 60° of abduction (elliptical: P < 0.001; spherical: P < 0.001). During internal rotation at 0° abduction, the spherical head showed significantly more compound motion (P = 0.042) compared to the elliptical head. The spherical implant also demonstrated increased anterior translation and compound motion during internal rotation at 60° abduction (P < 0.001) compared to the resting state. This difference was not significant for the native or elliptical head design at this angle (P > 0.05).ConclusionIn the setting of TSA, elliptical and spherical head implants showed similar obligate translation and overall compound motion during axial rotation. A gained understanding of the consequences of implant head shape in TSA may guide future surgical implant choice for better recreation of native shoulder kinematics and potentially improved patient outcomes.Level of evidenceControlled Laboratory Study.

The Association of Trunk and Hip Kinematic With Knee Abduction Angle During Single-Leg Landing

Objectives: Children aged 10 to 12 years often show dangerous maneuvers during landing, which include increased knee valgus, placing them at higher risk of anterior cruciate ligament (ACL) injuries. The study aimed to investigate the relation of the trunk and hip kinematics with the peak knee abduction angle during single-leg landing among preadolescent female soccer players. Methods: Thirty-six preadolescent female soccer players aged 10 to 12 years attended the study. Participants did a static trial and after that performed landing trials. A single-leg landing was applied to assess the landing kinematics. A three-dimensional motion capture system was applied to analyze trunk, hip, and knee kinematics. Results: Pearson correlation coefficient demonstrated a significantly positive relationship between peak hip internal rotation angle (r=0.361) (P=0.03) and peak knee abduction angle. Furthermore, no significant relationship was identified between peak hip adduction (r=-0.102) (P=0.55), peak trunk rotation (r=0.239) (P=0.16), peak trunk lateral flexion (r=0.052) (P=0.76), and peak valgus knee. Discussion: Peak hip rotation angle was correlated with the valgus knee with a weak correlation value among preadolescent female soccer players. Future studies should consider kinematic risk factors related to ACL injuries in combination with neuromuscular control trunk and hip during more demanding tasks.

Comparison between passive knee kinematics during surgery and active knee kinematics during walking: A preliminary study.

Recovery of function is among a patient's main expectations when undergoing total knee arthroplasty (TKA). However, normal gait knee function is not always completely restored, which can affect patient satisfaction and quality of life. Computer-assisted surgery (CAS) allows surgeons to evaluate passive knee kinematics intra-operatively. Understanding associations between knee kinematics measured during surgery and during daily activities, such as walking, could help define criteria for success based on knee function and not only on the correct alignment of the implant or the leg. This preliminary study compared passive knee kinematics measured during surgery with active kinematics measured during walking. Eight patients underwent a treadmill gait analysis using the KneeKG™ system both before surgery and three months afterwards. Knee kinematics were measured during CAS both before and after TKA implantation. The anatomical axes of the KneeKG™ and CAS systems were homogenised using a two-level, multi-body kinematics optimisation with a kinematic chain based on the calibration measured during CAS. A Bland-Altman analysis was performed before and after TKA for adduction-abduction angle, internal-external rotation, and anterior-posterior displacement over the whole gait cycle, at the single stance phase and at the swing phase. Homogenising the anatomical axes between CAS and treadmill gait led to limited median bias and limits of agreement (post-surgery -0.6 ± 3.6 deg, -2.7 ± 3.6 deg, and -0.2 ± 2.4 mm for adduction-abduction, internal-external rotation and anterior-posterior displacement, respectively). At the individual level, correlations between the two systems were mostly weak (R2 < 0.3) over the whole gait cycle, indicating low kinematic consistency between the two measurements. However, correlations were better at the phase level, especially the swing phase. The multiple sources of differences did not enable us to conclude whether they came from anatomical and biomechanical differences or from measurement system errors.

Superior Capsular Reconstruction Partially Restores Native Glenohumeral Joint Loads in a Dynamic Biomechanical Shoulder Model

To evaluate the effect of an irreparable posterosuperior rotator cuff tear (PSRCT) on glenohumeral joint loads and to quantify improvement after superior capsular reconstruction (SCR) using an acellular dermal allograft. Ten fresh-frozen cadaveric shoulders were tested using a validated dynamic shoulder simulator. A pressure mapping sensor was placed between the humeral head and glenoid surface. Each specimen underwent the following conditions: (1) native, (2) irreparable PSRCT, and (3) SCR using a 3-mm-thick acellular dermal allograft. Glenohumeral abduction angle (gAA) and superior humeral head migration (SM) were measured using 3-dimensional motion-tracking software. Cumulative deltoid force (cDF) and glenohumeral contact mechanics, including glenohumeral contact area and glenohumeral contact pressure (gCP), were assessed at rest, 15°, 30°, 45°, and maximum angle of glenohumeral abduction. The PSRCT resulted in a significant decrease of gAA along with an increase in SM, cDF, and gCP (P < .001, respectively). SCR did not restore native gAA (P < .001); however, SM was significantly reduced (P < .001). Further, SCR significantly reduced deltoid forces at 30° (P= .007) and 45° of abduction (P= .007) when compared with the PSRCT. SCR did not restore native cDF at 30° (P= .015), 45° (P < .001), and maximum angle (P < .001) of glenohumeral abduction. Compared with the PSRCT, SCR resulted in a significant decrease of gCP at 15° (P= .008), 30° (P= .002), and 45° (P= .006). However, SCR did not completely restore native gCP at 45° (P= .038) and maximum abduction angle (P= .014). In this dynamic shoulder model, SCR only partially restored native glenohumeral joint loads. However, SCR significantly decreased glenohumeral contact pressure, cumulative deltoid forces, and superior migration, while increasing abduction motion, when compared with the posterosuperior rotator cuff tear. These observations raise concerns regarding the true joint-preserving potential of SCR for an irreparable posterosuperior rotator cuff tear, along with its ability to delay progression of cuff tear arthropathy and eventual conversion to reverse shoulder arthroplasty.

Biomechanical Gender Differences in the Uninjured Extremity After Anterior Cruciate Ligament Reconstruction in Adolescent Athletes: A Retrospective Motion Analysis Study.

Introduction Subsequent anterior cruciate ligament (ACL) injury is more common in the pediatric population and encompasses graft failure and subsequent contralateral tears. Females are at a higher risk. The purpose of the present study was to compare the knee valgus angles at initial contact, knee extension moments, anterior and lateral knee joint forces, hip flexion angles, hip adduction moments, and ankle inversion during the drop vertical test in the uninjured extremity between adolescent males and females who had previously undergone an anterior cruciate ligament reconstruction (ACLR). Methods This IRB-approved retrospective chart review included patientsaged 8-18 years who were seen at the five to seven month postoperatively following ACL reconstruction. A total of 168 patients met our inclusion criteria (86 girls and 82 boys.) Using three-dimensional motion capture technology (CORTEX software, Motion Analysis Corp., Rohnert Park, CA), data were collected while the subject performed the drop vertical test over floor-mounted force plates (FP-Stairs, AMTI, Watertown, MA) under the direct supervision of a pediatric physical therapist. The Wilcoxon rank sum was used, and p < 0.05 was considered statistically significant. Results Females demonstrated a larger average knee joint extension moment (0.31 vs 0.28 N*m/kg, p = 0.0408), a larger anterior knee joint force at initial contact (3.51 vs. 2.79, N/kg, p = 0.0458), larger average hip flexion angle (41.50° vs. 35.99°, p = 0.0005), a smaller maximum hip adduction moment (0.92 vs. 1.16, N*m/kg, p = 0.0497), and a smaller average ankle inversion angle (5.08° vs. 6.41°, p = 0.03231). No significant differences were found regarding knee abduction angle or lateral knee joint force. Conclusions The biomechanical profile of the contralateral extremity varies significantly between the genders after ACLR. In the uninjured extremity, females may have larger hip flexion angles, smaller hip adduction moments, larger anterior knee joint forces, larger knee extension moments, and smaller ankle inversion angles as compared to males after ACLR. These findings may explain the higher incidence of subsequent contralateral injury in female adolescent athletes. Further work is required to develop a composite score that determines at-risk athletes.

Application of the Coupling Angle to Investigate Upper Limb Interjoint Coordination After Stroke

ObjectiveInterjoint coordination after stroke is affected, which limits the use of the upper limb. Current methods to determine interjoint coordination lack the ability to visualize and quantify the movement. Therefore we investigated if the coupling angle can be used to visualize and interpret upper limb interjoint coordination following a stroke. MethodsSeven chronic stroke patients trained six weeks with an assistive home-training system (MERLIN). Kinematic outcomes, i.e. elbow and shoulder range of motion, movement duration, and angle-angle plots were determined in a retrieving task. Interjoint coordination between elbow flexion and shoulder abduction angles was expressed as the coupling angle phases and the number of phase transitions: proximal/distal joint leading phase, in-phase and anti-phase. Comparisons were made within sides: pre-test versus post-test, and between sides: most-affected (MA) versus least-affected (LA). ResultsSmaller elbow flexion angles were found PreMA versus PreLA, and smaller shoulder abduction angles in PostMA versus PostLA. A general coordination pattern was revealed on the LA side, but not on the MA side. A trend showed less phase transitions at the MA side after training, suggesting a smoother movement. Quantification of the movement phases indicated more involvement of the shoulder joint involvement in the MA side during pre-test. After training, these differences were not apparent, which might reveal an increased independent control of the elbow joint. ConclusionsThe coupling angle and the movement phases provide a promising tool to investigate post-stroke interjoint coordination patterns. SignificanceA new visualisation of the interjoint coordination may benefit rehabilitation of stroke survivors. RegistrationThis trial was registered at the Netherlands Trial Register (NL7535) https://www.trialregister.nl/trial/7535.

Definition of High-Risk Motion Patterns for Female ACL Injury Based on Football-Specific Field Data: A Wearable Sensors Plus Data Mining Approach.

The aim of the present study was to investigate if the presence of anterior cruciate ligament (ACL) injury risk factors depicted in the laboratory would reflect at-risk patterns in football-specific field data. Twenty-four female footballers (14.9 ± 0.9 year) performed unanticipated cutting maneuvers in a laboratory setting and on the football pitch during football-specific exercises (F-EX) and games (F-GAME). Knee joint moments were collected in the laboratory and grouped using hierarchical agglomerative clustering. The clusters were used to investigate the kinematics collected on field through wearable sensors. Three clusters emerged: Cluster 1 presented the lowest knee moments; Cluster 2 presented high knee extension but low knee abduction and rotation moments; Cluster 3 presented the highest knee abduction, extension, and external rotation moments. In F-EX, greater knee abduction angles were found in Cluster 2 and 3 compared to Cluster 1 (p = 0.007). Cluster 2 showed the lowest knee and hip flexion angles (p < 0.013). Cluster 3 showed the greatest hip external rotation angles (p = 0.006). In F-GAME, Cluster 3 presented the greatest knee external rotation and lowest knee flexion angles (p = 0.003). Clinically relevant differences towards ACL injury identified in the laboratory reflected at-risk patterns only in part when cutting on the field: in the field, low-risk players exhibited similar kinematic patterns as the high-risk players. Therefore, in-lab injury risk screening may lack ecological validity.

Using an Affordable Motion Capture System to Evaluate the Prognostic Value of Drop Vertical Jump Parameters for Noncontact ACL Injury

Background: Knee kinematic parameters during a drop vertical jump (DVJ) have been demonstrated to be associated with increased risk of noncontact anterior cruciate ligament (ACL) injury. However, standard motion analysis systems are not practical for routine screening. Affordable and practical motion sensor alternatives exist but require further validation in the context of ACL injury risk assessment. Purpose/Hypothesis: To prospectively study DVJ parameters as predictors of noncontact ACL injury in collegiate athletes using an affordable motion capture system (Kinect; Microsoft). We hypothesized that athletes who sustained noncontact ACL injury would have larger initial and peak contact coronal abduction angles and smaller peak flexion angles at the knee during a DVJ. Study Design: Case-control study; Level of evidence, 3. Methods: 102 participants were prospectively recruited from a collegiate varsity sports program. A total of 101 of the 102 athletes (99%) were followed for an entire season for noncontact ACL injury. Each athlete performed 3 DVJs, and the data were recorded using the motion capture system. Initial coronal, peak coronal, and peak sagittal angles of the knee were identified by our software. Results: Five of the 101 athletes sustained a noncontact ACL injury. Peak coronal angles were significantly greater and peak sagittal flexion angles were significantly smaller in ACL-injured athletes (P = .049, P = .049, respectively). Receiver operating characteristic (ROC) analysis demonstrated an area under the curve of 0.88, 0.92, and 0.90 for initial coronal, peak coronal, and peak sagittal angle, respectively. An initial coronal angle cutoff of 2.96° demonstrated 80% sensitivity and 72% specificity, a peak coronal angle cutoff of 6.16° demonstrated 80% sensitivity and 72% specificity, and a peak sagittal flexion cutoff of 93.82° demonstrated 80% sensitivity and 74% specificity on the study cohort. Conclusion: Increased peak coronal angle and decreased peak sagittal angle during a DVJ were significantly associated with increased risk for noncontact ACL injury. Based on ROC analysis, initial coronal angle showed good prognostic ability, whereas peak coronal angle and peak sagittal flexion provided excellent prognostic ability. Affordable motion capture systems show promise as cost-effective and practical options for large-scale ACL injury risk screening.