The effect of capsular tightening on humeral head translations.

Idiopathic or surgical tightening of the glenohumeral joint capsule may cause displacement of the humeral head relative to the glenoid fossa and favor the development of instability and/or osteoarthritis. In the present investigation the relative position of the humerus to the glenoid fossa was determined at the end of the ranges of eight different passive movements before and after selective capsular plication in eight cadaveric shoulders to study the effects of selective capsular plications on the kinematics of the shoulder. While the capsule was in its unaltered state, translation of the humeral head was 3.8 mm superiorly in abduction, 7.3 mm antero-superiorly in flexion. In internal rotation in 0 degrees, 45 degrees and 90 degrees of abduction the head moved 6.1, 8.0 and 12.0 mm antero-inferiorly. In external rotation at 0 degrees of abduction the translation was 0.9 mm antero-inferiorly, at 45 degrees and 90 degrees of abduction it was 4.3 and 5.6 mm postero-inferiorly, respectively. Plications of the anterior part of the capsule reproducibly and significantly either increased or decreased translations during flexion (up to 5.9 mm anteriorly and up to 3.8 mm inferiorly), external rotation (up to 2.9 mm posteriorly and 1 mm inferiorly) and internal rotation (from 5.5 mm posteriorly to 2 mm anteriorly and up to 2.2 mm superiorly). Posterior plications had only little effect on translations (mainly a decrease of anterior translation during flexion of 2.8 mm). CLINICAL RELEVANCE: The 'obligate' glenohumeral translations which occur towards the end of passive shoulder movements are altered in a reproducible fashion by tightening specific parts of the glenohumeral joint capsule, as often carried out in treatment of shoulder instability. These alterations of the kinematics of the glenohumeral joint may be relevant for the development of static subluxation and osteoarthitis as seen after too tight plication in the treatment of instability [Int. Orthop. (SICOT) 67-B (1985) 709; J. Bone Joint Surg. Am. 72 (1990) 1193; J. Bone Joint Surg. Am. 66-A (1984) 169; J. Bone Joint Surg. Am. 65 (1983) 456].     

Effects of position and speed on eccentric and concentric isokinetic testing of the shoulder rotators

This study investigated the effects of position and speed on peak torque values of the shoulder internal and external rotators during concentric and eccentric activity. The dominant shoulder of 9 males and 10 females, 21-33 years, were tested at two velocities (60 and 180 degrees /sec) in two positions (45 degrees glenohumeral abduction and 45 degrees glenohumeral flexion) and two contraction types (eccentric and concentric). Results indicated that 1) concentric internal rotation decreased significantly (p < 0.0001) at the higher speed in males, 2) eccentric external rotation increased significantly (p < 0.003) at the higher speed in females, and 3) peak torque values were significantly greater (p < 0.01) in the 45 degrees glenohumeral abduction position compared to the 45 degrees glenohumeral flexion position during eccentric and concentric external rotation for both females and males, and for eccentric internal rotation in females. These findings are useful when planning to progress the intensity of the testing and training of the shoulder rotators according to patient tolerance. J Orthop Sports Phys Ther 1989;11(2):64-69.     

The effect of radiofrequency thermal capsulorrhaphy on glenohumeral translation, rotation, and volume

The purpose of this study is to evaluate the effects of radiofrequency (RF) thermal capsulorrhaphy on the kinematic properties of the glenohumeral joint as determined by changes in resistance to multidirectional translational forces, alteration in the range of internal and external rotation, and changes in glenohumeral joint volume. Nonablative RF thermal energy was used to contract the glenohumeral joint capsule in 6 cadaveric shoulders. Measurements of translation were made after application of a 30-N load in anterior, posterior, and inferior directions. The maximum arc of internal and external rotation after application of a 1-N-m moment was also determined for vented specimens before and after thermal capsulorrhaphy. The percent reduction in glenohumeral capsular volume was measured by use of a saline solution injection-aspiration technique. Capsular shrinkage resulted in reductions in anterior, posterior, and inferior translation. The largest percent reductions in anterior translation were seen in external rotation at 45 degrees (48%, P <.05) and 90 degrees (41%, P <.05) abduction. For inferior translation, the largest percent reductions were seen in internal rotation at 45 degrees (40%, P <.05) and 90 degrees (45%, P <.05) abduction. Reductions in posterior translation were noted in internal rotation at 45 degrees (27%, P <.05) and 90 degrees (26%, P <.05) abduction. Other changes in translation were observed but were not statistically significant. The maximum arc of humeral rotation was reduced by a mean of 14 degrees at 45 degrees abduction and 9 degrees at 90 degrees abduction. The mean percent reduction in capsular volume for all shoulders was 37% (range, 8%-50%). This could not be correlated with percent reductions in translation and rotation. This study demonstrated the significant effect of RF thermal capsulorrhaphy in reducing glenohumeral multidirectional translation and volume with only a small loss of rotation in cadaveric shoulders.     

Revision anterior capsular shoulder stabilization using hamstring tendon autograft and tibialis tendon allograft reinforcement: minimum two-year follow-up

Surgical treatment of anterior shoulder capsular deficiency has been a challenge for orthopaedic surgeons dealing with failed anterior shoulder stabilization procedures. We have used hamstring tendon autograft or tibialis tendon allograft to reinforce deficient anterior capsular tissue in patients with failed anterior shoulder stabilization. We performed a clinical follow-up of 15 patients at a minimum of 2 years after surgery, using the American Shoulder and Elbow Surgeons questionnaire, a physical examination, and radiographs. Thirteen patients were satisfied with their surgery. The mean American Shoulder and Elbow Surgeons score was 73, (range, 7-100). There were no postoperative dislocations. The operative shoulder had decreased range of motion compared with the contralateral shoulder. The operative arm lacked 10 degrees of forward flexion, 21 degrees of external rotation at the side, 24 degrees of external rotation with the arm in abduction, and 4 spinal levels of internal rotation. Two patients required total shoulder arthroplasty for painful glenohumeral arthritis. Clinical failure was related to glenohumeral arthritis or residual anterior shoulder apprehension. Our results support the use of hamstring autograft or tibialis anterior allograft for the reconstruction of the anterior capsule during revision shoulder stabilization surgery.     

A cadaveric model of the throwing shoulder: a possible etiology of superior labrum anterior-to-posterior lesions

BACKGROUND: It has been speculated that a shift of the throwing arc commonly develops in athletes who perform overhead activities, resulting in greater external rotation and decreased internal rotation caused by anterior capsular laxity and posterior capsular contracture, respectively. Osseous adaptation in the form of increased humeral and glenoid retroversion may provide a protective function in the asymptomatic athlete but cannot explain the pathological changes seen in the shoulder of the throwing athlete. Therefore, the objective of the present study was to examine the biomechanical effects of capsular changes in a cadaveric model. METHODS: Ten cadaveric shoulders were tested with a custom shoulder-testing device. Humeral rotational range of motion, the position of the humerus in maximum external rotation, and glenohumeral translations in the anterior, posterior, superior, and inferior directions were measured with the shoulder in 90 degrees of abduction. Translations were measured with the humerus secured in 90 degrees of external rotation. To simulate anterior laxity due to posterior capsular contracture, the capsule was nondestructively stretched 30% beyond maximum external rotation with the shoulder in 90 degrees of abduction. This was followed by the creation of a 10-mm posterior capsular contracture. Rotational, humeral shift, and translational tests were performed for the intact normal shoulder, after anterior capsular stretching, and after simulated posterior capsular contracture. RESULTS: Nondestructive capsular stretching resulted in a significant increase in external rotation (average increase, 18.2 degrees 2.1 degrees ; p < 0.001), and subsequent simulated posterior capsular contracture resulted in a significant decrease in internal rotation (average decrease, 8.8 degrees +/- 2.3 degrees ; p = 0.02). There also was a significant increase in anterior translation with the application of a 20-N anterior translational force after nondestructive capsular stretching (average increase, 1.7 +/- 0.3 mm, p = 0.0006). The humeral head translated posteroinferiorly when the humerus was rotated from neutral to maximum external rotation. This did not change significantly in association with anterior capsular stretching. Following simulated posterior capsular contracture, there was a trend toward a more posterosuperior position of the humeral head with the humerus in maximum external rotation in comparison with the position in the stretched conditions, although these differences were not significant. CONCLUSIONS: A posterior capsular contracture with decreased internal rotation does not allow the humerus to externally rotate into its normal posteroinferior position in the cocking phase of throwing. Instead, the humeral head is forced posterosuperiorly, which may explain the etiology of Type-II superior labrum anterior-to-posterior lesions in overhead athletes.     

The effect of arm position and capsular release on rotator cuff repair. A biomechanical study.

A cadaver study was performed to determine the effect of arm position and capsular release on rotator cuff repair. Artificial defects were made in the rotator cuff to include only the supraspinatus (small) or both supraspinatus and infraspinatus (large). The defects were repaired in a standard manner with the shoulder abducted 30 degrees at the glenohumeral joint. Strain gauges were placed on the lateral cortex of the greater tuberosity and measurements were recorded in 36 different combinations of abduction, flexion/extension, and medial/lateral rotation. Readings were obtained before and after capsular release. With small tears, tension in the repair increased significantly with movement from 30 degrees to 15 degrees of abduction (p < 0.01) but was minimally affected by changes in flexion or rotation. Capsular release significantly reduced the force (p < 0.01) at 0 degree and 15 degrees abduction. For large tears, abduction of 30 degrees or more with lateral rotation and extension consistently produced the lowest values. Capsular release resulted in 30% less force at 0 degree abduction (p < 0.05).     

Effect of joint compression on inferior stability of the glenohumeral joint

To determine the relative importance of negative intraarticular pressure, capsular tension, and joint compression on inferior stability of the glenohumeral joint we studied 17 fresh, normal adult cadaver shoulders using a "3 degrees of freedom" shoulder test apparatus. Translations were measured in intact and vented shoulders while a 50-N superior and inferior directed force was applied to the shoulder. Three different joint compressive loads (22 N, 111 N, 222 N) were applied externally. Tests were performed in 3 positions of humeral abduction in the scapular plane (0 degree, 45 degrees, 90 degrees) and in 3 positions of rotation (neutral, maximal internal, and maximal external). After tests of the intact and vented shoulder, the glenohumeral ligaments were sectioned and tests were repeated. With minimal joint compression of 22 N, negative intraarticular pressure and capsular tension limited translation of the humeral head on the glenoid. Increasing the joint compressive load to 111 N resulted in a reduction of mean inferior translation from 11.0 mm to 2.0 mm at 0 degree abduction, from 21.5 mm to 1.4 mm at 45 degrees abduction, and from 4.5 mm to 1.2 mm at 90 degrees abduction. With a compressive load of 111 N, venting the capsule or sectioning of glenohumeral ligaments had no effect on inferior stability. Clinical relevance: Glenohumeral joint compression through muscle contraction provides stability against inferior translation of the humeral head, and this effect is more important than negative intraarticular pressure or ligament tension.     

Addressing glenohumeral stiffness while treating the painful and stiff shoulder arthroscopically.

The shoulder can be primarily or secondarily stiff. Cadaveric cutting studies have shown increases in passive range of glenohumeral motion when certain portions of the capsule are released. This study has recorded the intraoperative gains made in passive range of motion for external rotation, flexion, abduction, and internal rotation with sequential release of the rotator interval, inferior capsule, and posterosuperior capsule, regardless of initial etiology, and followed-up over time. Thirty one of 60 shoulders, found clinically to have a loss of passive range of motion and having failed a nonoperative approach, underwent a capsular release. Eighteen patients underwent a partial capsular release (group 1) and 13 patients (group 2) underwent a complete capsular release. Thirty of 31 shoulders had statistically significant gains in passive range of motion with sequential release. In general, resection of the rotator interval contributed to gains in external rotation; resection of the inferior capsule (anteroinferior and posteroinferior) contributed gains to external rotation, forward flexion, and internal rotation; and resection of the posterosuperior capsule contributed to gains only in internal rotation. At a minimum of 18 months follow-up, 30 of 31 shoulders retained their intraoperative gains. There was no difference in the results between primarily and secondarily stiff shoulders for motion gains (P >.05). Arthroscopically addressing capsular tightness is beneficial in returning shoulders with a loss of passive glenohumeral motion to normal regardless of the etiology.     

The immediate effects of soft tissue mobilization with proprioceptive neuromuscular facilitation on glenohumeral external rotation and overhead reach

STUDY DESIGN: Randomized controlled 2-group. pretest-posttest, multivariate study of patients with shoulder musculoskeletal disorders. OBJECTIVES: The purpose of this study was to evaluate the immediate effect of soft tissue mobilization (STM) with proprioceptive neuromuscular facilitation (PNF) to increase glenohumeral external rotation at 45 degrees of shoulder abduction and overhead reach. BACKGROUND: It is postulated that limitation in glenohumeral external rotation, when measured at 45 degrees of shoulder abduction, represents subscapularis muscle flexibility deficits and is associated with the inability to fully reach overhead. No research, however, is available to demonstrate whether intervention strategies intended to improve subscapularis flexibility and glenohumeral external rotation range of motion at 45 degrees of shoulder abduction will improve a patient's ability to reach overhead. METHODS AND MEASURES: Twenty patients (10 males, 10 females; age range, 21-83 years) with limited glenohumeral external rotation and overhead reach of 1 year duration or less served as subjects. The subjects were randomly assigned to a treatment group, which consisted of soft tissue mobilization to the subscapularis and proprioceptive neuromuscular facilitation to the shoulder rotators, or a control group. Goniometric measurements of glenohumeral external rotation at 45 degrees abduction and overhead reach were taken preintervention and immediately postintervention for the treatment group or at prerest and postrest periods for the control group. RESULTS: The treatment group improved by a mean of 16.4 degrees (95% confidence interval [CI, 12.5 degrees-20.3 degrees) of glenohumeral external rotation, as compared to less than a 1 degree gain (95% CI, -0.2 degrees-2.0 degrees) in the control group (P < .0005). Overhead reach in the treatment group improved by a mean of 9.6 cm (95% CI, 5.2-14.0 cm) in comparison to a mean gain of 2.4 cm (95% CI, -0.8-5.6 cm) for the control group (P = .009). CONCLUSION: These findings suggest that a single intervention session of STM and PNF was effective for producing immediate improvements in glenohumeral external rotation and overhead reach in patients with shoulder disorders.     

Anterior-inferior capsular shift of the shoulder: a biomechanical comparison of glenoid-based versus humeral-based shift strategies

This study compared the biomechanical effects of an anterior-inferior capsular shift based at the humeral side with one on the glenoid side of the joint on resultant multidirectional glenohumeral translation and rotation. Nine matched pairs of fresh cadaveric shoulders were placed in a testing apparatus that constrained 3 rotations but allowed simultaneous free translation of the humeral head with respect to the glenoid. The right and left shoulders of each of the matched pairs were randomized to undergo either a glenoid-based or humeral-based anterior capsular shift. The shoulders were tested vented and following the capsular shift procedure. Translational testing was performed at 0 degrees, 45 degrees, and 90 degrees of glenohumeral elevation with the humerus in neutral rotation, 30 degrees internal rotation, and 30 degrees external rotation. Sequential loads of 30 N in anterior, posterior, and inferior directions were applied while maintaining a 22-N joint compressive load. The maximum arc of internal and external rotation after application of a 1-newton-meter moment was determined for the vented specimens and then after the capsular shift procedure. Both shift strategies resulted in significant limitation of anterior, posterior, and inferior translation in all of the tested positions. No significant differences were noted between the 2 shift strategies with respect to restriction of translation in the anterior or inferior directions. The glenoid-based shift caused a significantly greater decrease in posterior translation at 45 degrees and 90 degrees of abduction. With respect to rotation, the glenoid-based shift exerted significantly greater restriction on external rotation than the humeral-based shift. This study supports the use of either a humeral-based or glenoid-based shift to control multidirectional glenohumeral instability. Greater reduction in external rotation was demonstrated after the glenoid-based shift. Specific differences demonstrated in translation control for humeral-based versus glenoid-based capsular shift procedures may be useful in tailoring a procedure for specific instability patterns.     

Loss of total arc of motion in collegiate baseball players

Published studies on asymptomatic athletes show an increase in external rotation and decrease in internal rotation while maintaining the total arc of motion of the glenohumeral joint. The purpose of this study was to determine whether overhand athletes with shoulder pain maintained their total arc of motion. Sixty-seven college-level baseball players were examined. Internal rotation and external rotation of the glenohumeral joint, measured at 90 degrees of abduction, and total arc of shoulder motion were compared between dominant and nondominant extremities in athletes with and without shoulder pain. Dominant shoulders in the pain group had a mean arc of 136.2 degrees compared with 145.8 degrees in the nondominant group, for a side-to-side difference of 9.6 degrees. We demonstrate that college-level baseball players with shoulder pain have a significant decrease in total arc of shoulder motion and internal rotation compared with their nondominant shoulder and with pain-free athletes.     

Modified Bankart procedure for recurrent anterior dislocation and subluxation of the shoulder in athletes

Thirty-four athletes (34 shoulders) with recurrent anterior glenohumeral instability were treated with a modified Bankart procedure, using a T-shaped capsular incision in the anterior capsule. The inferior flap was advanced medially and/or superiorly and rigidly fixed at the point of the Bankart lesion by a small cancellous screw and a spike-washer. The superior flap was advanced inferiority and sutured over the inferior flap. Twenty-five athletes (median age: 22) were evaluated over a mean period of follow-up of 65 months. The clinical results were graded, according to Rowe, as 22 (88%) excellent, 3 (12%) good, and none as fair or poor. The mean postoperative range of movement was 92 degrees of external rotation in 90 degrees of abduction. Elevation and internal rotation was symmetrical with the opposite side. Twenty-four patients returned to active sport, 22 at their previous level. This modified Bankart procedure is an effective treatment for athletes with recurrent anterior glenohumeral instability.     

Comparison of glenohumeral mechanics following a capsular shift and anterior tightening

BACKGROUND: Numerous surgical techniques have been developed to treat glenohumeral instability. Anterior tightening procedures have been associated with secondary glenohumeral osteoarthritis, unlike the anterior-inferior capsular shift procedure, which has been widely advocated as a more anatomical repair. The objective of the present study was to quantify glenohumeral joint translations, articular contact, and resultant forces in cadaveric specimens in order to compare the effects of unidirectional anterior tightening with those of the anterior-inferior capsular shift. METHODS: Six normal fresh-frozen cadaveric shoulders were tested on a custom rig with use of a coordinate-measuring machine to obtain kinematic measurements and a six-axis load transducer to measure resultant external joint forces. Shoulders were tested in the scapular plane in three configurations (normal anatomical, anterior tightening, and anterior-inferior capsular shift) and in three humeral rotations (neutral, internal, and external). Glenohumeral articular surface geometry was quantified with use of stereophotogrammetry for kinematic and contact analyses. Resultant joint forces were computed on the basis of digitized coordinates of tendon insertions and origins. RESULTS: Compared with the controls (maximum elevation, 167 degrees 8 degrees ), the anteriorly tightened specimens demonstrated loss of external rotation, significantly restricted maximum elevation (135 degrees 16 degrees , p = 0.002), posterior-inferior humeral head subluxation, and significantly greater posteriorly directed resultant forces at higher elevations (p < 0.05). In contrast, compared with the controls, the specimens that had been treated with the anterior-inferior capsular shift demonstrated a similar maximum elevation (159 degrees +/- 11 degrees , p = 0.8) without any apparent loss of external rotation and with reduced humeral translation. CONCLUSIONS: Anterior tightening adversely affects joint mechanics by decreasing joint stability, limiting both external rotation and arm elevation, and requiring greater posterior joint forces to attain maximum elevation. The anterior-inferior capsular shift improves joint stability while preserving external rotation with no significant loss of maximum elevation.     

Moment arms of the shoulder muscles during axial rotation

The objective of the present study was to determine the instantaneous moment arms of 18 major muscle sub‐regions crossing the glenohumeral joint in axial rotation of the humerus during coronal‐plane abduction and sagittal‐plane flexion. The tendon‐excursion method was used to measure instantaneous muscle moment arms in eight entire upper‐extremity cadaver specimens. The results showed that the inferior subscapularis was the largest internal rotator; its rotation moment arm peaks were 24.4 and 27.0 mm during abduction and flexion, respectively. The inferior infraspinatus and teres minor were the greatest external rotators; their respective rotation moment arms peaked at 28.3 and 26.5 mm during abduction, and 23.3 and 22.1 mm during flexion. The two supraspinatus sub‐regions were external rotators during abduction and internal rotators during flexion. The latissimus dorsi and pectoralis major behaved as internal rotators throughout both abduction and flexion, with the three pectoralis major sub‐regions and middle and inferior latissimus dorsi displaying significantly larger internal rotation moment arms with the humerus adducted or flexed than when abducted or extended (p < 0.001). The deltoid behaved either as an internal rotator or an external rotator, depending on the degree of humeral abduction and axial rotation. Knowledge of moment arm differences between muscle sub‐regions may assist in identifying the functional effects of muscle sub‐region tears, assist surgeons in planning tendon transfer surgery, and aid in the development and validation of biomechanical computer models. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:658–667, 2011     

Rotator interval dimensions in different shoulder arthroscopy positions: a cadaveric study

The rotator interval was defined as a triangular structure, where the base of the triangle was the coracoid base, the upper border was the anterior margin of the supraspinatus, and the lower border was the superior margin of the subscapularis muscle-tendon unit. We evaluated the rotator interval dimensions in 15 shoulders from 10 lightly embalmed adult cadavers in 3 shoulder arthroscopy positions: 0 degrees of abduction and 30 degrees of flexion (beach chair [BC]), 45 degrees of abduction and 30 degrees of flexion (lateral decubitus 1), and 70 degrees of abduction and 30 degrees of flexion (lateral decubitus 2). In each shoulder position, measurements were made in neutral rotation (NR), 45 degrees of external rotation (ER), and 45 degrees of internal rotation (IR). The coracoid base lengthened with IR in all positions and shortened in ER in the lateral decubitus position but not in the BC position. Abduction significantly lengthened the coracoid base, which was shortest in the BC position with ER (24 +/- 4 mm) and longest in the lateral decubitus 2 position with IR (33 +/- 5 mm). The coracoid base, where sutures are placed during plication of the interval, was observed to lengthen and, therefore, loosen with IR and abduction. To prevent postoperative ER restriction, plication should be made in ER or neutral rotation when operating in the BC position and the degree of abduction should be decreased and the shoulder held in ER when operating in the lateral decubitus position.     

Shoulder arthrodesis in adult brachial plexus injury: what is the optimal position?

Brachial plexus injuries are a major indication for shoulder arthrodesis. However, there is no consensus concerning the optimal position of the glenohumeral joint for fusion. Between 1997 and 2008, 19 shoulder arthrodeses were performed using pelvic reconstruction plates. The radiographic and functional characteristics of 13 patients of mean age 46 years were examined at a mean of 101 months after arthrodesis. Arthrodeses showed 30° mean angle of abduction, 32° forward flexion and 44° internal rotation of the humerus with respect to the scapula. Abduction >35° and forward flexion ≥30° seem to offer slightly better functional results. Internal rotation ≤45° significantly relates to better ability of the hand to reach the face (p = 0.012). Neither abduction >35° nor forward flexion ≥30° showed a higher prevalence of periscapular pain. Abduction around 35° and forward flexion around 30° are needed for good functional results. Internal rotation should not exceed 45°.     

Coracoacromial ligament tension in vivo

Tension in the coracoacromial (CA) ligament has been postulated as the mechanism of acromial spur formation. Five patients (mean age, 58 years) undergoing open rotator cuff repair were recruited. A differential variable reluctance transducer (DVRT) was inserted into the CA ligament parallel to the fiber orientation. The DVRT measured linear displacement as the glenohumeral joint was moved through 90 degrees of abduction and full internal/external rotation. The CA ligament was then removed with the DVRT in situ. The specimen was mounted on a material-testing machine. Load was applied in the line of the CA ligament fibers, and the DVRT output recorded. The CA ligament was found to be under tension, which was lowest with the arm adducted (mean, 8.9 N; range, 3.7-22 N) and highest in abduction (mean, 15.7 N; range, 6.5-38 N). This study confirms CA ligament tension in vivo as a possible stimulus for acromial spur formation.     

关节镜下盂肱关节前方松解对原发性冻结肩的早期疗效

目的观察应用关节镜进行关节囊前方松解术对原发性冻结肩的治疗效果。 方法2015年3月至2017年3月陕西省人民医院收治的60例原发性冻结肩患者,所有患者经术前MRI检查或术中探查确诊,排除由其余肩部疾病(骨折、肩峰撞击、肩袖损伤、钙化性肌腱炎)引起的继发性冻结肩,所有患者应用关节镜行盂肱关节前方松解术。采集术前及术后的疼痛视觉评分(VAS)、Constant评分、复旦大学肩关节功能评分系统(FUSS),应用单因素重复测量方差分析对结果进行统计学分析评估,对肩关节各方向的被动活动度应用配对t检验方法进行统计学分析。 结果所有患者术后均未出现腋神经损伤或肩关节不稳等并发症。与术前相比,术后12周时患者的VAS评分[(0.7±0.6)vs (8.1±0.7),F ＝38.01]、Constant评分[(93.9±3.0)vs (34.2±3.4),F ＝121.42]及FUSS评分[(93.8±1.3)vs (40.1±2.2),F ＝220.09]差异有统计学意义(均为P <0.01);同时,与术前相比,患肩被动外展[(152±13)° vs (74±9)°,t ＝37.678]、前屈[(156±12)° vs (60±10)°,t ＝46.469]、体侧外旋[(66±11)° vs (8±3)°,t ＝37.762]及内旋在术后12周时明显改善(均为P <0.01)。 结论应用关节镜对盂肱关节囊前方结构进行彻底松解,可有效改善原发性冻结肩患者肩关节功能。     

Determining the resting position of the glenohumeral joint: a cadaver study

STUDY DESIGN: Single-session repeated-measures design. OBJECTIVE: To define the resting position of the glenohumeral joint by investigating the magnitude of the anterior and posterior displacements of the humeral head and medial and lateral rotation ranges of motion (ROMs) of the glenohumeral joint at different abduction angles in cadaver specimens. BACKGROUND AND PURPOSE: The resting position of a joint is the position in the joint's ROM at which the joint capsule has its greatest laxity. It is frequently chosen as the position for assessing and treating joints with dysfunction. However, no study has been conducted to determine the resting position of the glenohumeral joint. METHODS: Seven freshly frozen cadaver shoulder specimens (age at time of death [mean +/- SD] was 66.9 +/- 2.5 years) were studied. Specimens were mounted on a system that uses computer-controlled hydraulics and motors to induce and monitor translation and rotation movements of the glenohumeral joint. The magnitudes of total displacement (DTotal) of the head of the humerus and total ROM (RTotal) of the glenohumeral joint were measured in the plane of the scapula at 0 degrees (neutral), 30 degrees, 40 degrees, 50 degrees, 60 degrees, and the end range of glenohumeral joint abduction. The resting position was determined as the midpoint of the shared range of the 95% to 99.9% confidence intervals of the predicted abduction position where the peaks of displacement and rotation occurred. RESULTS: The DTotal measurements (mean +/- SD) at 0 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degrees, and the end range of glenohumeral joint abduction were 30.53 +/- 9.35, 44.87 +/- 7.34, 45.35 +/- 8.53, 43.99 +/- 10.02, 39.63 +/- 9.85, and 23.80 +/- 10.42 mm, respectively. The RTotal measurements (mean +/- SD) for the same positions were 67.15 degrees +/- 15.87 degrees, 95.64 degrees +/- 24.26 degrees, 98.88 degrees +/- 29.56 degrees, 97.08 degrees +/- 30.17 degrees, 90.91 degrees +/- 28.73 degrees, and 63.48 degrees +/- 25.93 degrees, respectively. The resting position was located at 39.33 degrees +/- 4.37 degrees of glenohumeral abduction (45.13% +/- 7.58% of the available abduction ROM). The resting position (Y) varied linearly with the maximum available abduction ROM (X) (Y = 0.607X - 13.120, R2 = 0.679, F = 10.61, P = 0.023). There was a main effect of joint position on both displacement (P<0.001) and rotation ROM (P<0.001). CONCLUSION: In the plane of the scapula, the resting position of the glenohumeral joint (angle measured between the scapula and humerus) occurred at 39 degrees of abduction (45% of the maximum available abduction ROM) and varied linearly with the amount of available abduction ROM. This finding suggests that in patients with glenohumeral joint hypomobility the resting position is located closer to neutral and that evaluation and treatment should be initiated accordingly at a smaller angle of abduction than the traditional resting position. Our data were derived from cadaver specimens, therefore, caution should be taken when generalizing the results of the present study to a patient population.