Internal Rotation External Rotation Research Articles

Humeral head size predicts baseplate lateralization in reverse shoulder arthroplasty: a comparative computer model study

BackgroundIn reverse shoulder arthroplasty (RSA), the ideal combination of baseplate lateralization (BL), glenosphere size (GS) and overhang (GOH) with a commonly used 145° neck shaft angle (NSA) is unclear. This is the first study evaluating correlations of body height (BH), humeral head size (HS), glenoid height (GH) and association of gender with best glenoid configurations for range of motion (ROM) maintaining anatomic lateralization (aLAT) for optimized muscle length in 145° and less distalized 135° RSA. MethodsIn this computer model study, 22 CTs without joint narrowing were analyzed (11 male/female). A standardized semi-inlay 145° platform stem was combined with 20 glenoid configurations (baseplate (B) 25, 25+3/+6 lateralized (l), 29, 29+3/6l combined with glenosphere36, 36+2eccentric (e), 36+3l, 39, 39+3e, 39+3l , 42, 42+4e). Abduction-adduction, flexion-extension, external rotation-internal rotation, total ROM (TROM) and total notching relevant (TNR) ROM were computed, best TROM models respecting aLAT (-1mm to +1mm) and HS/GH recorded. Secondly, the 145° models (Ascend Flex stem; Stryker, Kalamazoo, MI, USA) were converted and compared to a 135° inlay RSA (New Perform stem; Stryker, Kalamazoo, MI, USA) maintaining GOH (6.5-7mm) and aLAT. ResultsBest 145° models had eccentric glenospheres (mean BL: 3.5mm, GOH 8.8mm, GS 38.1mm, distalization (DIS) 23mm). The 135° models had concentric glenospheres, mean BL 3.8mm, GOH 6.9mm, GS 39.7mm, DIS 14.1mm. Head size showed the strongest positive correlation with BL in 145° and 135° models (0.65/0.79). Despite reduced GOH in smaller females with a 135° NSA, adduction, external rotation, extension, TNR ROM and TROM were significantly increased (p=0.02, p=0.005, p=0.005, p=0.004, p=0.003), abduction however reduced (p=0.02). The same trends were seen for males. ConclusionsHead size is a practical measure in surgery or preoperatively, and the strong positive correlation with BL is a useful planning aid. Despite reduction of GOH, conversion to a less distalized 135° NSA is powerful to maintain and even significantly increase all components of TNR ROM (extension/external rotation/adduction) in small females with the drawback of reduced abduction which may however be compensated by scapula motion. Lateralization with a less distalized 135° RSA optimizes muscle length, may facilitate subscapularis repair and maintains highest rigid body motion.

Combined femoral and tibial component total knee arthroplasty device rotation measurement is reliable and predicts clinical outcome

BackgroundThe optimal total knee arthroplasty (TKA) rotational alignment and how best to obtain and measure it are debatable. The aim was to analyse the reliability of the Berger femoral, three different tibial and four different combined two-dimensional computer tomography (2D-CT) TKA component rotation measurements, and to ascertain which rotational values best predict a successful clinical outcome.MethodsThe 2D-CT scans were obtained post-operatively on 60 patients who had TKA. We determined one femoral [Berger’s femoral angle (BFA)], three tibial [Berger’s tibial angle (BTA), anatomical tibial angle (ATA) and bimalleolar posterior tibial component angle (BM_PTCA)] and four combined [transepicondylar posterior tibial component angle (TE_PTCA), bicondylar posterior tibial component angle (BC_PTCA, transepicondylar bimalleolar angle (TE_BM) and bicondylar bimalleolar angle (BC_BM)] TKA rotation angles. We made all measures in 23 patients twice by three observers and determined inter- and intra-observer agreement using the Bland–Altman plot method. We analysed measures of 55 patients using the area under the ROC curve (AUC) analysis to ascertain the discriminative capacity of BFA, ATA, TE_PTCA and BC_PTCA for predicting a successful clinical outcome according to the Knee Society Score (KSS) threshold.ResultsATA showed the smaller inter- and intra-observer average of differences (−0.1° and 1.6°, respectively) of the studied methods followed by BFA (−0.9° and 1.4°), TE_PTCA (−2.1° and 2.7°) and BC_PTCA (−0.5° and 1.8°). BFA (−4° to 2.1° and −6.1° to 8.8°) and BC_PTCA (−4.4° to 3.4° and −7.9° to 4.4°) showed the narrower inter- and intra-observer limits of agreement. A TKA device rotation (BC_PTCA) < 0.8° of external rotation (ER) predicted a KSS and KSS knee successful outcome, and < 3.8° ER for KSS functional (AUC = 0.889; 0.907 and 0.764, respectively). BFA and ATA < 0.9° ER and < 3.9° internal rotation (IR) predicted a successful KSS knee outcome (AUC = 0.796 and 0.889, respectively).ConclusionThe ATA tibial component rotation measurement was the most reliable of those studied. BFA, TE_PTCA and BC_PTCA were reliable measures for TKA femoral and combined rotation. The presence of a minimal rotation between the TKA components (BC_PTCA) and a small femoral ER or tibial IR predicted a successful KSS outcome.Level of evidence II.

Poster 161: Musculoskeletal Adaptations to Baseball Pitching Differ Markedly Between Righthand Dominant Versus Lefthand Dominant Pitchers

Objectives: Musculoskeletal adaptations on the dominant arm of baseball pitchers are typically (1) a gain in glenohumeral external rotation (ER) range of motion (ROM), (2) a loss of glenohumeral internal rotation (IR) ROM, (3) posterior shoulder tightness, (4) weakness in the empty can test, and (5) increased IR strength. The purpose of this study was to determine if these adaptations differed between righthand dominant (RHD) versus lefthand dominant (LHD) pitchers. Based on recent work it was hypothesized that ROM adaptations would be less apparent in LHD pitchers, but strength adaptations would not differ between RHD and LHD pitchers. Methods: Shoulder ROM and strength were measured in 327 baseball pitchers in preseason screening (91 were tested on more than one season, 418 player-seasons, 322 RHD vs. 96 LHD). There were 157 youth pitchers (age 11-15 yr) 146 adolescent pitchers (age 16-17 yr) and 115 adult pitchers (age 18-24 yr). ER ROM, IR ROM and posterior shoulder ROM (Tyler test) were measured with a digital level. Empty can, ER, IR and scapular retraction strength were measured with a hand-held dynamometer. Differences between the dominant and nondominant arms, between RHD and LHD pitchers, and between age groups, were assessed using mixed model analysis of variance (mean and SD reported). Results: ROM Adaptations RHD pitchers had 11±10° more ER ROM on the dominant versus nondominant arm (P&lt;0.001) but LHD pitchers had no ER ROM difference (0±10°, P=0.685). The difference in ER ROM between RHD and LHD pitchers (P&lt;0.001) was unaffected by age (P=0.829). IR ROM loss on the dominant versus nondominant arm for RHD pitchers (10±11°) was greater (P&lt;0.001) than for LHD pitchers (5±10°). This difference was apparent for youth pitchers (RHD 9±9° vs. LHD 1±9°, P&lt;0.001) and adolescent pitchers (RHD 12±10 vs. LHD 5±11°, P&lt;0.001) but not for adult pitchers (RHD 9±14° vs. LHD 8±10°, P=0.863; RHD vs. LHD by Age Group P=0.040). Total ROM (ER+IR ROM) adaptations also differed between RHD and LHD pitchers (P&lt;0.001) and this effect was more apparent in the adult pitchers (Age Group by RHD vs. LHD P=0.027): RHD adult pitchers had a 4±15° gain in total ROM on the dominant side (P=0.007) while LHD adult pitchers had a 7±10° loss in total ROM on the dominant side (P=0.002). Posterior shoulder tightness on the dominant side was affected by arm dominance and age (P=0.038); for youth and adolescent pitchers there was no difference between RHD and LHD pitchers (youth RHD 6±13° vs. LHD 10±11°, P=0.156; adolescent RHD 5±10° vs. LHD 8±15°) but for adult pitchers, posterior shoulder tightness was greater for RHD versus LHD pitchers (6±8° vs. 1±11°, P=0.032). Strength Adaptations For the empty can test, RHD pitchers were weaker on the dominant versus nondominant arm (5±15%, P&lt;0.001) while there was no difference between the dominant and nondominant arms for LHD pitchers (3±16% stronger on dominant side P=0.100; RHD vs. LHD P&lt;0.001). For IR strength, RHD pitchers were stronger on the dominant arm (7±17%, P&lt;0.001) while there was no difference between the dominant and nondominant arms for LHD pitchers (2±21% P=0.360; RHD vs. LHD P=0.032). By contrast, for scapular retraction strength, LHD pitchers were stronger on the dominant arm (6±19%, P=0.007) while there was no difference between the dominant and nondominant arms for RHD pitchers (0±15% P=0.723; RHD vs. LHD P=0.003). Dominant versus nondominant ER strength was not different between RHD and LHD pitchers (P=0.323). Conclusions: The typical strength and ROM adaptations seen in baseball pitchers were mostly absent, or diminished, in LHD pitchers, but with some age dependent effects for ROM. Adult RHD pitchers had IR ROM loss and posterior shoulder tightness, but paradoxically adult LHD pitchers had IR ROM loss without associated posterior shoulder. The opposite was the case for youth and adolescent pitchers, with LHD pitchers having posterior shoulder tightness in the absence of IR ROM loss. Differences in strength adaptations between RHD and LHD pitchers have not been reported previously. Epidemiological studies examining the role of strength and ROM in injury risk for baseball pitchers have not previously accounted for differences between lefthanded and righthanded pitchers.

SAĞLIKLI GENÇ YETİŞKİNLERDE HALAT VE KÜREK EGZERSİZLERİNİN FİZİKSEL PERFORMANS ÜZERİNE ETKİLERİNİN KARŞILAŞTIRILMASI

Amaç&#x0D; Halat egzersizleri, fiziksel performansı artırmak için&#x0D; geniş çaplı ve ağır halatların kullanıldığı pliyometrik&#x0D; egzersiz yaklaşımıdır. Kürek egzersizleri ise genel vücut&#x0D; kuvvetini artıran, kapalı ortamda kürek çekme aletiyle&#x0D; yapılan bir egzersiz türüdür. Çalışmanın amacı,&#x0D; bu iki egzersiz yaklaşımının omzun internal rotasyon/&#x0D; eksternal rotasyon (IR/ER) kas kuvvetine, propriyosepsiyonuna,&#x0D; üst ekstremite dengesine, alt ekstremite&#x0D; kuvveti ve gövde stabilizasyonuna etkilerinin karşılaştırılmasıdır.&#x0D; Gereç ve Yöntem&#x0D; Araştırmaya, 18-25 yaşları aralığında sağlıklı 22 birey&#x0D; dahil edilmiştir. Çalışma başlangıcında ve sonunda;&#x0D; 60°/sn açısal hızdaki izokinetik dinamometre ile IR/&#x0D; ER omuz kas kuvvet testi, izokinetik dinamometre ile&#x0D; 15°, 45° ve 75° hedef açılarda aktif IR/ER omuz propriyosepsiyon&#x0D; ölçümü, üst ekstremite için Y denge testi&#x0D; ve kapalı kinetik zincir alt ekstremite stabilite testi gerçekleştirilmiştir.&#x0D; Katılımcılar randomize olarak kürek&#x0D; (n=10) ve halat (n=12) egzersiz gruplarına ayrılmıştır.&#x0D; Her iki gruba da 6 hafta boyunca, haftada 3 gün, gün&#x0D; aşırı, 6 set egzersiz ve setler arasında 30 sn dinlenmeyle&#x0D; egzersizler yapılmıştır. Egzersizler sırasındaki&#x0D; ritmi takip edebilmek için halat egzersiz grubunda 60&#x0D; bpm, kürek grubunda 30 bpm metronom hızı belirlenmiştir.&#x0D; Bulgular&#x0D; Egzersiz programlarından sonra; her iki grubun da&#x0D; (Kürek; n=9 / Halat; n=10) başlangıca göre kapalı kinetik&#x0D; zincir alt ekstremite stabilite testi ve IR total iş&#x0D; sonucunda anlamlı artış bulunmuş (p˂0,05), Üst Ekstremite&#x0D; Y Denge Testi ve propriyosepsiyon testi sonuçlarında&#x0D; fark olmadığı görülmüştür (p˃0,05). Halat&#x0D; egzersizi grubunun; dominant omzunun 60˚/s hızındaki&#x0D; IR zirve torku (p=0,048) ve vücut ağırlığına oranı&#x0D; (p=0,045) egzersiz programının sonunda, başlangıca&#x0D; göre anlamlı olarak artmıştır. Egzersiz programı-&#x0D; nın başlangıcına göre egzersiz programı sonrasında&#x0D; belirlenen değişim miktarlarının karşılaştırılmasında&#x0D; iki grup arasında birbirine üstünlük gözlenmemiştir&#x0D; (p&gt;0,05).&#x0D; Sonuç&#x0D; Mevcut sonuçlar ışığında iki egzersiz protokolünün de&#x0D; sağlık bireylerde antrenman programlarının bir parçası&#x0D; haline getirilebileceğini düşünmekteyiz.

Investigating The Association Between Supraspinatus Tendon Abnormality, Shoulder Pain and Isokinetic Strength in Elite Swimmers: A Cross-Sectional Study.

Shoulder pain is common among elite swimmers due to the tremendous stress over shoulders during swimming. Supraspinatus muscle is one of the major prime movers and stabilizers of shoulder and is highly susceptible to overloading and tendinopathy. An understanding of the relationship between supraspinatus tendon and pain; and between supraspinatus tendon and strength would assist health care practitioners for developing training regime. The objectives of this study are to evaluate 1) the association between structural abnormality of supraspinatus tendon and shoulder pain and 2) the association between structural abnormality of supraspinatus tendon and shoulder strength. We hypothesized that structural abnormality of supraspinatus tendons positively associated with shoulder pain and negatively associated with shoulder muscle strength among elite swimmers. 44 elite swimmers were recruited from the Hong Kong China Swimming Association. Supraspinatus tendon condition was evaluated using diagnostic ultrasound imaging and shoulder internal and external rotation strength was evaluated by the isokinetic dynamometer. Pearson's R was used to study the correlation between shoulder pain and supraspinatus tendon condition and to evaluate the association between isokinetic strength of shoulders and supraspinatus tendon condition. 82 shoulders had supraspinatus tendinopathy or tendon tear (93.18%). However, there was no statistically significant association between structural abnormality of supraspinatus tendon and shoulder pain. The results showed that there was no association between supraspinatus tendon abnormality and shoulder pain and there was a significant correlation between left maximal supraspinatus tendon thickness (LMSTT) and left external rotation/ concentric (LER/Con) and left external rotation/ eccentric (LER/Ecc) shoulder strength (p < 0.05) while internal rotation/ external rotation (IR/ER) ratio can also be a significant predicator on LMSTT >6mm (R2 = 0.462, F = 7.016, df = 1, p = 0.038). Structural change of supraspinatus tendon was not associated with shoulder pain, but could be a predictor on MSTT >6mm in elite swimmers.

The Efficacy of the Mulligan Concept to Treat Meniscal Pathology: A Systematic Review.

Meniscal pathologies are common knee injuries and arthroscopic surgery is the current accepted gold standard for treatment. However, there is evidence to support the use of the Mulligan Concept (MC) Mobilization with Movement (MWM) for meniscal pathologies including the 'Squeeze' technique, tibial internal rotation (IR), and tibial external rotation (ER). The purpose of this systematic review was to critically appraise the literature to investigate the effectiveness of MC MWMs for meniscal lesions on patient reported pain, function, and multi-dimensional health status in patients with clinically diagnosed meniscal pathologies. Systematic Review. A literature search was completed across multiple databases using combinations of the words "knee, function, mobilization with movement, MWM, mulligan concept, MC, meniscal pathology, meniscal derangement, and meniscal tear." Studies written within the prior 10 years that examined MC MWM techniques to treat knee meniscal injury were included. Articles that met the inclusion criteria (used MC MWM 'Squeeze' technique, tibial IR, or tibial ER for treatment of clinically diagnosed meniscal pathologies; Patient reported outcome [PRO] measures had to be used in the assessment of knee pain or function) were analyzed for quality. Randomized control trials were analyzed using the PEDro scale and the Downs & Black (D&B) checklist, case series were analyzed using the Joanna Briggs Institute (JBI) checklist, and case reports were analyzed using the CARES checklist. Six articles met the inclusion criteria and were included in this review, two randomized controlled studies, two case series, and two case reports consisting of 72 subjects. All six papers included reports of improvements in pain and function that were either statistically significant or met the minimal clinically important difference (MCID). Five studies reported the Disablement in the Physically Active (DPA) scale that also demonstrated statistically significant differences or met the MCID. The MC MWM 'Squeeze' technique, tibial IR, or tibial ER demonstrated the ability to reduce pain, improve function, and improve patient perceived disability following treatment of a clinically diagnosed meniscal pathology. These studies demonstrated short term results lasting from one week to 21 weeks. Treatment interventions incorporating MC MWM techniques demonstrated reduction of pain and improvement in function in the short term in patients with clinically diagnosed meniscal pathologies. 2a.

Hip Range of Motion and Strength in Male Athletes with Stage 1 Osteitis Pubis: A Cross-Sectional and Correlational Study.

Background: The objectives of this study were: (1) to determine whether athletes with stage 1 osteitis pubis (OP) present differences in hip range of motion (ROM) and muscle strength, between both sides and compared with healthy athletes; (2) to investigate the relationship between the internal rotation (IR) ROM and pain intensity and physical function. Methods: a cross-sectional and correlational study was designed, in which 30 athletes (15 athletes with stage 1 OP and 15 healthy athletes) were included. Pain intensity, physical function, hip ROM and hip muscle strength were assessed. Results: The ROM assessment reported significant differences between both groups in the IR, external rotation (ER) and adduction (ADD) ROM of the painful side (PS) (p < 0.05). The OP group showed differences between both sides in IR ER and ADD ROM (p < 0.05). No statistically significant differences were found between or within groups in the maximum isometric strength of the hip (p > 0.05). A strong negative correlation between pain intensity and IR ROM (r = −0.640) and a strong positive correlation between physical function and IR ROM (r = 0.563) were found in the OP group. Conclusions: Male athletes with stage 1 OP present a hip IR, ER and ADD ROM limitation in the PS compared to non-PS and to healthy athletes. IR ROM is correlated to pain intensity and physical function in athletes with stage 1 OP.

Paper 05: The Role of the Long Head of the Biceps Tendon in Posterior Shoulder Stabilization during Forward Flexion

Objectives:The incidence of long head of the biceps tendon (LHBT) procedures is increasing, yet the role of the LHBT in glenohumeral stability is not fully understood. People lift most objects in the sagittal plane with forward flexion, which stresses the posterior aspect of the unconstrained glenohumeral joint. Determining the mechanism by which the shoulder maintains stability with functional motions is important to understanding the pathoanatomy of degenerative shoulders. We hypothesize that the LHBT resists posterior translation of the humeral head (HH) during forward flexion by tensioning the posterior capsuloligamentous complex.Methods:Ten fresh-frozen cadaveric shoulders were tested using an established shoulder simulator, which loads the rotator cuff, deltoid and LHB tendons through a system of pulleys and weights. A motion tracking system recorded glenohumeral translations with an accuracy of ±0.2mm. In each subject, the scapula was fixed and the humerus was tested in 6 positions: 30 and 60 degrees of glenohumeral forward flexion at i) maximum internal rotation (IR), ii) neutral rotation and iii) maximum external rotation (ER) (Figure 1). The deltoid was loaded with 100N, and the infraspinatus and subscapularis were loaded with 22N each. The difference in glenohumeral translation was calculated at each position comparing the LHBT loaded with 45N or unloaded.Results:When comparing the two states of LHBT loading vs unloading, unloading the LHBT led to an overall increase in posterior and superior translation of the humeral head (Figure 2) in all tested positions (neutral, maximum internal rotation, maximum external rotation in both 30 and 60 degrees of forward flexion). At 30 degrees of glenohumeral forward flexion, unloading the LHBT increased HH posterior translation by 2.46mm (±0.92mm) (p<0.001), 1.71mm (±1.02mm) (p<0.001) and 1.02mm (±0.88mm) (p=0.014) at maximum ER, neutral rotation, and maximum IR, respectively (Figure 3). At 60 degrees of glenohumeral forward flexion, unloading the LHBT increased HH posterior translation by 2.77mm (±1.16mm) (p<0.001), 2.43mm (±1.56mm) (p<0.001) and 1.66mm (±1.42mm) (p<0.001) at maximum ER, neutral rotation and maximum IR, respectively (Figure 4). Unloading the LHBT led to more posterior translation at 60 degrees of glenohumeral forward flexion compared to 30 degrees (p=0.013).Conclusions:LHBT loading resists posterior translation of the humeral head during forward flexion. This data supports the role of the LHBT as a posterior stabilizer of the shoulder, specifically when a person is carrying objects in front of them. Biceps tenotomy or tenodesis may contribute to microinstability of the glenohumeral joint and shift contact pressure posteriorly. Further work is needed to determine if unloading the LHBT, as is done with biceps tenotomy or tenodesis, may eventually contribute to the posterior glenoid wear seen with osteoarthritis.

The role of the long head of the biceps tendon in posterior shoulder stabilization during forward flexion.

The role of the long head of the biceps tendon (LHBT) in glenohumeral stability is not fully understood. Most objects are lifted in the sagittal plane with forward flexion, which stresses the posterior aspect of the unconstrained glenohumeral joint. Determining the mechanism by which the shoulder maintains stability with functional motions is important to understanding the pathoanatomy of degenerative shoulders. Our hypothesis was that the LHBT resists posterior translation of the humeral head (HH) during forward flexion by tensioning the posterior capsuloligamentous complex. Ten fresh-frozen cadaveric shoulders were tested using an established shoulder simulator that loads the LHBT, rotator cuff, and deltoid tendons through a system of pulleys. A motion tracking system recorded glenohumeral translations with an accuracy of ±0.2 mm. In each subject, the scapula was fixed and the humerus was tested in 6 positions: 30° and 60° of glenohumeral forward flexion at (1) maximum internal rotation (IR), (2) neutral rotation, and (3) maximum external rotation (ER). The deltoid was loaded with 100 N, and the infraspinatus and subscapularis were loaded with 22 N each. The difference in glenohumeral translation was calculated at each position comparing the LHBT loaded with 45 N or unloaded. At 30° of glenohumeral forward flexion, unloading the LHBT increased HH posterior translation by 2.5 mm (±0.9 mm; P<.001), 1.7 mm (±1.0 mm; P<.001), and 1.0 mm (±0.9 mm; P=.01) at maximum ER, neutral rotation, and maximum IR, respectively. At 60° of glenohumeral forward flexion, unloading the LHBT increased HH posterior translation by 2.8 mm (±1.2 mm; P<.001), 2.4 mm (±1.6 mm; P<.001), and 1.7 mm (±1.4 mm; P<.001) at maximum ER, neutral rotation, and maximum IR, respectively. LHBT loading resists posterior translation of the HH during forward flexion. These data support the role of the LHBT as a posterior stabilizer of the shoulder, specifically when a person is carrying objects in front of them. Further work is needed to determine if unloading the LHBT, as is done with biceps tenotomy or tenodesis, may eventually lead to posterior labral pathology, or to the posterior glenoid wear commonly seen with osteoarthritis.

Does grip strength correlate with rotator cuff strength in patients with atraumatic shoulder instability?

AimTo investigate if there is a correlation between grip strength (GS) and rotator cuff (RC) strength in patients with atraumatic shoulder instability (ASI) and to compare the relationship between these two measures with that previously published for a healthy population. Moreover, to determine if testing GS could be incorporated as a surrogate clinical assessment for RC strength in these patients.MethodsA total of 20 subjects with ASI were included. Out of the 20 patients, eight presented with bilateral instability, which constituted a total of 28 atraumatic unstable shoulders (N = 28). GS was measured using a Jamar hand-dynamometer. External rotation (ER) and internal rotation (IR) strength was tested in inner and outer ranges using a hand-held dynamometer (HHD). Pearson’s correlation test was computed to investigate the relationship. Multiple linear regression was conducted to predict GS based on RC strength.ResultsSignificant and strong positive correlations were found between GS and inner-range IR (r = 0.764, P < 0.001), inner-range ER (r = 0.611, P = 0.001), outer-range IR (r = 0.817, P < 0.001), and outer-range ER (r = 0.736, P < 0.001). A significant regression equation was found (F (4, 23) = 13.254, P < 0.001), with an R2 of 0.697 indicating that RC strength explained 69.7% of the variance in GS.ConclusionsThe results support the hypothesis showing that GS is strongly associated with RC strength in ASI patients. The simplicity of handgrip testing allows it to be used in clinical scenarios where sophisticated assessment tools are not available. GS is a convenient means to monitor patient progress during shoulder rehabilitation programs.

Relationship Differences in Pre-season Isometric Shoulder Strength, Humeral Torsion and Shoulder Range of Motion in Collegiate Baseball Players (218)

Objectives:Muscle strength, humeral torsion (HT) and shoulder range of motion (ROM) have been linked to throwing performance and injury risk in baseball players. Research suggests that players who demonstrate an isometric shoulder external rotation (ER)/internal rotation (IR) strength ratio of <0.75 are at a higher risk for developing a throwing-related upper extremity injury. While the relationships between HT and shoulder ROM have been examined in the literature, few studies have examined the potential relationships between these variables and isometric shoulder strength. The purpose of this study was to examine the relationships between isometric shoulder strength, HT and shoulder ROM at the start of each baseball season in a cohort of healthy junior college baseball players.Methods:Ninety-two healthy junior college baseball players (mean age=19.9±0.8 years) were prospectively assessed at the start of 2 consecutive spring seasons. Variables measured included HT, shoulder ROM and isometric shoulder strength. Both the dominant (D) and non-dominant (ND) shoulders of each player were assessed throughout the study. Chi square tests and bivariate Pearson correlation coefficients were calculated to examine between group differences and the relationships between variables. Statistical significance was set a priori at α=0.05.Results:33.7% of junior college players demonstrated a D shoulder ER/IR strength ratio of <0.75 at the start of baseball season. Pitchers and position players demonstrated no significant differences in D shoulder ER/IR strength ratios at the start of the season (P=.40). Additionally, moderate positive relationships were observed between D HT and D IR ROM (r=0.35; P=.001) as well as D horizontal adduction (HA) ROM (r=0.43; P<.001). A moderate relationship was also observed between ND HT and ND IR ROM (r=0.56, P<.001), however ND ER and HA ROM demonstrated weaker relationships respectively (ER: r=-0.27; P=.01; HA: r=0.26; P=.01). Inverse relationships were observed between HT and ER strength in both the D and ND shoulders (D: r=-0.27, P=.01; ND: r=-0.28, P=.007). Internal rotation ROM was also inversely correlated with ER strength (r=-0.29, P=0.005) and ER/IR strength ratios (r=-0.31, P=.003), but only in the D shoulder. No significant correlations were observed between ROM and strength in the ND shoulder.Conclusions:One third of the junior college baseball players in this study began the season with marked deficits in D shoulder strength, irrespective of their position. We then examined the relationships between HT, shoulder ROM and isometric shoulder strength and confirmed the previously established correlation between HT and shoulder ROM. Moreover, there appeared to be inverse relationships between HT and ER strength in both the D and ND shoulders as well as IR ROM and ER strength in the D shoulder. This study emphasizes the importance of pre-season rotator cuff strength training, with an emphasis on improving ER strength, to potentially aid in the prevention of throwing-related upper extremity injuries in collegiate baseball players. Humeral torsion and shoulder ROM may influence isometric shoulder strength, however more research is needed to better understand these relationships in the throwing shoulder.

Immobilization in External Rotation Reduces the Risk of Recurrence After Primary Anterior Shoulder Dislocation: A Meta-analysis.

Background:The best method for nonsurgical treatment after primary dislocation of the shoulder is not clear. The efficacy of immobilization with the arm in external rotation (ER) compared with internal rotation (IR) remains controversial.Purpose:To determine the efficacy of ER immobilization versus IR immobilization on recurrence rate after primary dislocation of the shoulder from the evidence of randomized controlled trials.Study Design:Systematic review; Level of evidence, 2.Methods:Electronic databases (MEDLINE [Ovid SP], PubMed, Web of Science, EBM reviews, and CINAHL) and available proceedings according to the abstracts of major international meetings related to or including shoulder injuries and trauma were used to search for randomized controlled trials. Two independent investigators determined eligibility and carried out data extraction from the selected studies.Results:A total of 9 studies (817 patients) were selected for this meta-analysis. They included 668 male and 149 female patients, with a mean age ranging from 20.3 to 37.5 years. In the 9 pooled studies, the recurrence rate of shoulder dislocation was 21.5% (84/390) in the ER group versus 34.9% (130/373) in the IR group. ER immobilization significantly reduced the recurrence rate compared with IR immobilization (risk ratio, 0.56; P = .007). In the subgroup analysis of those immobilized full-time, ER immobilization was significantly more effective than IR immobilization in reducing the recurrence rate (risk ratio, 0.57; P = .01). In the subgroup analysis of age, ER immobilization was significantly more effective than IR immobilization in those aged 20 to 40 years but not in those younger than 20 years.Conclusion:This meta-analysis demonstrates that ER immobilization reduces the recurrence rate after primary shoulder dislocation compared with IR immobilization in patients older than 20 years. When treating a patient with primary shoulder dislocation, the clinician should provide this information to the patient before a treatment method is selected.

Does an effective shoulder injury prevention program affect risk factors in handball? A randomized controlled study.

Shoulder problems are common in handball, but injury risk reduction is possible by implementing a prevention program. However, player compliance to the program remains a challenge, with feedback from players that the program is too time consuming. To develop a more efficient program, we aimed to assess the effect of the Oslo Sports Trauma Research Center shoulder injury prevention program on external rotation (ER) strength and internal rotation (IR) range of motion (ROM), considered to represent key risk factors for injury. Four youth handball teams (three females, one males, 57 players, mean age 17.1years) were randomized to an intervention or control group. The intervention program was conducted three times per week as a part of handball warm-up for 18weeks, supervised by physical therapists. The main outcome variables were the between-group differences in ER strength and IR ROM change from baseline to postintervention. Isometric ER strength was measured with a handheld dynamometer and IR ROM with a digital goniometer. Mean dominant shoulder isometric ER strength increased both in the intervention (10%) and the control group (6%) during the intervention, but there was no significant group by time interaction (group difference: 0.06N/kg (95% CI: -0.04 to 0.17). IR ROM did not change in either group during the intervention. The Oslo Sports Trauma Research Center shoulder injury prevention program did not affect the risk factors ER strength and IR ROM. The preventive effect of the program must therefore be due to other factors.

CORRELATION OF UPPER AND LOWER EXTREMITIES ISOKINETIC STRENGTH IN ELITE MALE

Background and purposeMuscle strength is one of the most physically important parameters during the competition for judokas. Studies have shown that for judokas, strength in especially the knee and shoulder muscles and the strength balance between right and left sides is very important in terms of both staying in balance and doing spe-cific techniques correctly. Our study aims to find out the correlations between isokinetic lower and upper extremity strength in elite judokas and to examine bilateral and contralateral strength ratios. MethodsThis study is designed according to cross-experimental design with randomized repeated measurements. Fifteen male (mean values: age 19.40 ± 1.24 years, height 170.55 ± 9.44 cm, weight 78.47 ± 18.55 kg, and BMI 27.02 ± 5.82 kg/m2) elite judokas between the ages of 18 and 21 participated voluntarily in the study. Knee extension (EX) and flexion (FLX), shoulder internal rotation (IR) and external rotation (ER) isoki-netic strength measurements of the subjects were measured with concentric/concentric (Con/Con) con-tractions at 60o s-1 and 180o s-1 angular velocities. Ipsilateral hamstring/quadriceps (H/Q), internal rotation/external rotation (IR/ER), contralateral Q/Q, H/H, IR/IR, ER/ER ratios were calculated through lower and upper extremity isokinetic strength. Shapiro–Wilk, Levene, paired sample t-test, and Pearson correlation test were used in statistical analyses. ResultsIn terms of the ipsilateral strength ratios on dominant (DS) and nondominant (NDS) in lower and upper extremities, a significant difference was found only at 60° s-1 angular velocity in only the lower extremity on DS (P 0.05). High correlations were found between all other parameters (P > 0.05). ConclusionsIn conclusion, it was found that lateral asymmetric ratios may differ in elite judokas especially at low angu-lar velocities; however, this difference was not at a level to cause the risk of injury, DS and NDS showed similar strength in both lower and upper extremity, and there were high positive correlations between lower and upper extremity strength.

Acute and Subacute Changes in Hip Strength and Range of Movement After Arthroscopy to Address Chondrolabral Pathology

Background: Hip pain is associated with reduced muscle strength, range of movement (ROM), and function. Hip arthroscopy is undertaken to address coexistent intra-articular pathologies with the aim of reducing pain and improving function. Purpose: To evaluate changes in strength and ROM in a cohort with chondrolabral pathology before surgery to 3 and 6 months after hip arthroscopy. Study Design: Case series; Level of evidence, 4. Methods: Sixty-seven individuals with hip pain who were scheduled for hip arthroscopy were matched with 67 healthy controls. Hip strength and ROM were collected preoperatively and at 3 and 6 months postoperatively. Repeated measures analysis of variance evaluated whether strength and ROM differed between limbs and among time points. Bonferroni post hoc tests determined differences in hip strength and ROM among testing times and between the hip pain group and matched controls. Results: Hip extension, internal rotation (IR), external rotation (ER), and adduction (P < .040) strength were greater at 3 months after surgery; all directions, including flexion, abduction, and squeeze, were greater at 6 months (P < .015). Hip flexion ROM was greater at 3 months after surgery (P = .013). Flexion, IR, and ER ROM was greater at 6 months (P < .041). At 6 months, IR ROM (P = .003) and flexion, IR, and ER strength (P < .005) remained less than matched controls. Conclusion: With the exception of squeeze and flexion, all directions of hip strength and hip flexion ROM are significantly improved 3 months after arthroscopy to address chondrolabral pathology. By 6 months after arthroscopy, strength in all directions and flexion and rotation ROM are significantly improved in both limbs, but hip flexion, IR, and ER strength and IR ROM remain significantly less than that of healthy matched controls in both limbs.

Differentiation of bony and soft-tissue adaptations of the shoulder in professional baseball pitchers

Baseball pitching places tremendous forces on the arm, which may lead to structural tissue adaptations that are represented by changes in rotational range of motion (ROM). These adaptations often include both bony and soft tissue; however, the contribution of each tissue to the change in motion is not always clinically attainable. The purposes of this study were to determine the adaptations of ROM, bone, and soft tissue bilaterally and to examine the correlation between clinical ROM and humeral retroversion (HR)-corrected ROM. We hypothesized that glenohumeral internal rotation (IR) and total motion would be decreased and glenohumeral external rotation (ER), posterior capsule thickness (PCT), and HR would be increased in the dominant arm; that HR-corrected ROM would be significantly different than clinical ROM; and that HR-corrected ROM would be correlated with total motion difference. Thirty professional baseball pitchers participated in this study. HR, PCT, and glenohumeral IR and ER were evaluated in the dominant and nondominant shoulders of each subject. The dominant arm exhibited significantly more retroversion, ER, and PCT than the nondominant arm. The dominant arm also had significantly less IR and total motion than the nondominant arm. The total ROM difference was significantly correlated with both HR-corrected glenohumeral IR deficit and ER gain. HR-corrected glenohumeral IR deficit and ER gain may more accurately reflect the contribution of soft-tissue changes to ROM. Unfortunately, measurement of HR is not always clinically attainable, making clinical management difficult.

Effects of 7-Week Shoulder Exercise Intervention on Joint Mobility, Strength and Function in Diabetics and Non-Diabetics

Objective of the study was to compare the effects of a 7-week shoulder exercise program on shoulder range of motion(ROM), strength, and function between diabetics/pre-diabetics and non-diabetics. Shoulder ROM (internal rotation(IR) and external rotation(ER)), strength (elevation, retraction, IR, and ER), and function were assessed pre/post intervention. Shoulder function was assessed using Disabilities of the Arm, Shoulder, and Hand(DASH) and Shoulder Pain and Disability Index(SPADI). Improvements in variables were compared between groups using mix-model ANOVAs. Two pre-diabetics participants developed shoulder pain and were excluded from analysis. These participants were significantly older compared to the rest of the participants (69.0 vs. 55.7 years). After excluding these participants, there were no significant group differences (7diabetics/pre-diabetics vs. 8 non-diabetics) in intervention effects. In both groups, intervention resulted in improved ER ROM(p=.002), IR(p=.004) and ER strength(p=.010), DASH(p=.010) and SPADI(p=.025) scores. Shoulder exercises improved shoulder mobility, strength, and function in diabetics and non-diabetics alike. Introduction of shoulder exercises appears to be beneficial in improving shoulder function, regardless of diabetes status. However, caution may be needed when working with older diabetic patients, as they may be more prone to developing shoulder pain.

Sports Physical Therapy Section Poster Presentations (Abstracts SPO1-SPO166).

These abstracts are presented here as prepared by the authors. The accuracy and content of each abstract remain the responsibility of the authors. In the identification number above each abstract, SPO designates a Sports Physical Therapy Section poster presentation. J Orthop Sports Phys Ther 2018;48(1):A203-A276. doi:10.2519/jospt.2018.48.1.A203.

Ultrasound Screening for Posterior Shoulder Dislocation in Infants with Brachial Plexus Birth Palsy: Level 4 Evidence

▴This presentation will discuss Materialise computer planning in skeletally immature patients. Clinical examination may fail to detect posterior shoulder dislocation in infants with brachial plexus birth palsy (BPBP).1Pöyhiä T.H. Lamminen A.E. Peltonen J.I. Kirjavainen M.O. Willamo P.J. Nietosvaara Y. Brachial plexus birth injury: US screening for glenohumeral joint instability.Radiology. 2010; 254: 253-260Crossref PubMed Scopus (42) Google Scholar The purpose of this study was to determine the prevalence of shoulder dislocation in this population on ultrasound (US) and to determine whether physical examination (PE) measurements correlate with US findings. Infants presenting to our BPBP clinic receive serial shoulder US exams until age 1 year. We retrospectively reviewed data for infants with concurrent physical exam and US prior to 1 year of age, but before any surgical intervention. PE consisted of Active Movement Scale (AMS) and passive external rotation of the shoulder in adduction (PERAdd) and abduction (PERAbd). US measurements included percentage of humeral head displaced posterior to the axis of the scapula (PHHD) and the alpha angle (intersection of posterior scapular margin with a line tangential to the humeral head through the glenoid).2Vathana T. Rust S. Mills J. Wilkes D. Browne R. Carter P.R. et al.Intraobserver and interobserver reliability of two ultrasound measures of humeral head position in infants with neonatal brachial plexus palsy.J Bone Joint Surg Am. 2007; 89: 1710-1715Crossref PubMed Scopus (31) Google Scholar Shoulder dislocation was defined as both PHHD > 0.5 and alpha angle > 30 degrees. PE results were compared between infants demonstrating dislocation at some time versus infants with no evidence of dislocation. We used receiver operating characteristic (ROC) analysis to evaluate the association between PE and concurrent US results. Sixty-six infants contributed a total of 118 ultrasound examinations (mean 1.8, range 1-5). Nineteen (28.8%) demonstrated shoulder dislocation, first detected at a range of 2.1-10.5 months of age. Of these, 14 (74%) presented with a dislocated shoulder at their first ultrasound. Infants with a dislocated shoulder demonstrated significantly less mean PERAdd (mean 46 versus 71 degrees) and a greater difference between internal rotation and external rotation scores on the AMS scale (mean 5.5 point versus 3.3 point difference) than those with a reduced shoulder (Table 1). PERAdd was better able to discriminate between concurrent evidence of dislocation and no dislocation (area under ROC curve [AUC] 0.89) than was the shoulder rotation difference (AUC = 0.73). A cut-off of 60 degrees for PERAdd yielded a sensitivity of 94% and a specificity of 69% for predicting dislocation on US (Figure 1). •Twenty-nine percent of infants seen in a BPBP specialty clinic had a shoulder dislocation during their first year of life.•Limited PERAdd and a large internal rotation - external rotation (IR-ER) difference on the AMS were associated with dislocation.•US shoulder screening is recommended for infants with BPBP, especially those with limited PERAdd.•US screening when PERAdd is = 60 degrees would identify an estimated > 90% of dislocations with a false positive rate < 30%.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Angle Specific Analysis of Side-to-Side Asymmetry in the Shoulder Rotators

Abstract: Although side-to-side asymmetry of the shoulder rotators calculated by independent peak torque (IPT) has been used for interpretation of injury risks in athletes, it may not measure strength through the entire range of motion (ROM) tested. The aim of this study was to compare side-to-side asymmetry of the shoulder rotators between independent peak torque (IPT) and ten-degree angle specific torque (AST). Twenty healthy adult males (24.65 ± 2.4 years) performed concentric and eccentric internal rotation (IR) and external rotation (ER) of the preferred and non-preferr ed arms on an isokinetic dynamometer at 60°/s through 150° of total ROM. The total ROM was divided into 14 ten-degree angles of the physiological ROM from −90° of ER to 60° of IR. Concentric and eccentric IR IPT (10.5% ± 8.7% and 12.1% ± 7.2%) and ER IPT (13.6% ± 9.8% and 8.7% ± 5.6%) were significantly less than AST at several angles ( p < 0.05). IPT might lead to erroneous interpretations of side-to-side asymmetry in the shoulder rotators and does not represent the entire ROM tested. This information could be us ed to prescribe strength exercises to enhance overhead performance and reduce risk of shoulder injuries.