Offener posterior-inferiorer Kapselshift zur Behandlung der atraumatischen hinteren Schulterinstabilität

OBJECTIVE: Restoration of functional stability and full range of shoulder mobility. INDICATIONS: Atraumatic, recurrent posterior dislocation or subluxation in cases of excessive posterior joint capsular volume without clinically relevant destruction of the glenoid or dysplasia. Additional procedure for traumatic posterior instability after reattachment of the labrum or screw fixation of the posterior glenoid fragment. CONTRAINDICATIONS: Capsular shift should not be an isolated procedure in glenoid hypoplasia and/or glenoid retroversion > 15 degrees (relative). Multidirectional instability (relative). Deliberate (psychogenic) posterior instability (relative). SURGICAL TECHNIQUE: Lateral decubitus position, Rockwood approach. Dissection of the posterior joint capsule after split of the external rotator muscles between the infraspinatus and teres minor. T-shaped incision of the posterior capsule with a medial base of about 0.5-1 cm lateral to the posterior glenoid rim. Retraction of the caudal and cranial capsular flaps. Inspection of the posterior labrum. If the labrum is detached, anatomic refixation of the labrum with suture anchors. The caudal flap is shifted cranially and medially in adduction and about 20 degrees external rotation. The cranial flap is then shifted caudally and medially. Suture with close-meshed Vicryl sutures. This creates double-contouring centrally and plication of the posterior capsule with reduction of the pathologically increased capsule volume. After wound closure and sterile dressing, the preoperatively prepared antirotation cast is applied and should be worn for 6 weeks. RESULTS: From 10/2002 to 09/2004, eight patients with atraumatic, isolated posterior shoulder instability were treated using the technique described above. All patients were available to follow-up 2 years after the operation. There were no perioperative complications and no neurologic deficits related to surgery. All patients achieved freedom of movement at the shoulder joint. In two patients, recurrent posterior dislocation occurred after the 7th and 23rd postoperative month.     

Biomechanical benefits of anterior offsetting of humeral head component in posteriorly unstable total shoulder arthroplasty: A cadaveric study

Restoration of joint stability during total shoulder arthroplasty can be challenging in the face of severe glenoid retroversion. A novel technique of humeral head component anterior‐offsetting has been proposed to address posterior instability. We evaluated the biomechanical benefits of this technique in cadaveric specimens. Total shoulder arthroplasty was performed in 14 cadaveric shoulders from 7 donors. Complementary shoulders were assigned to either 10° or 20° glenoid retroversion, with retroversion created by eccentric reaming. Two humeral head component offset positions were tested in each specimen: The anatomic (posterior) and anterior (reverse). With loads applied to the rotator cuff and deltoid, joint contact pressures and the force and energy required for posterior humeral head translation were measured. The force and energy required to displace the humeral head posteriorly increased significantly with the anterior offset position compared to the anatomic offset position. The joint contact pressures were significantly shifted anteriorly, and the joint contact area significantly increased with the anterior offset position. Anterior offsetting of the humeral head component increased the resistance to posterior humeral head translation, shifted joint contact pressures anteriorly, and increased joint contact area, thus, potentially increasing the joint stability in total shoulder arthroplasty with simulated glenoid retroversion. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:666–674, 2016.     

肩关节不稳定的肩盂骨缺损评估:肩盂下部圆心的确定

目的 探讨在正常肩盂CT三维重建标准正面观影像上确定肩盂下部圆心的可行性,比较同一个体左、右肩盂的半径大小,为术前精确定量评估肩盂骨缺损比例提供影像学依据. 方法 本研究测量了35例成人双侧正常肩盂(共70个),每个肩盂均行64层螺旋CT扫描,由1位医生在三维工作站上获得肩盂的标准三维正面观影像及标尺,并将其以二维图像的格式导出.3位医生分别利用AutoCAD2006软件对图像进行处理,做肩盂下部前缘最突点、下缘最突点连线的垂直平分线,再做后缘最突点、下缘最突点连线的垂直平分线,将两垂直平分线的交点定为肩盂下部的圆心,分别测量该点到肩盂前下缘、后下缘和后缘的距离.比较3位医生测量的圆心到肩盂前下缘、后下缘和后缘距离值,以及左、右肩盂相应距离的测量数据. 结果 肩盂下部圆心到肩盂后缘最突点之间的距离(即圆的半径)为(14.1±1.6)mm,到肩盂前下缘的距离为(14.0±1.7)mm,到肩盂后下缘的距离为(14.1±1. 6)mm.3位医生测量的圆心到肩盂后缘距离值之间及左、右肩盂相应测量值之间差异均无统计学意义(P>0.05). 结论 在正常肩盂的CT三维标准正面观影像上利用肩盂下部前、后、下缘最突点确定肩盂下部圆心的方法是简便、可行的,可重复性较高.正常人左右肩盂下部的半径是一致的.以上结论可用于单侧肩盂骨缺损的精确定量评价.     

Posterior instability

Posterior shoulder instability is a pathology that is increasingly seen in athletes. Excessive capsular laxity was originally proposed as the key component. Recent cadaveric and arthroscopic work has identified the importance of glenolabral integrity and glenoid depth in maintaining glenohumeral stability. Arthroscopic techniques to treat posterior instability are emerging. Until recently, reports of arthroscopic reconstruction focused entirely on capsular glenohumeral stability by altering two separate mechanisms: deepening of the glenoid concavity and reducing the capsular joint volume. This is accomplished by shifting the capsule to buttress the glenoid labrum. Thus increasing capsular tension increases the resultant compressive force vector into a deepened glenolabral concavity that, when combined together, enhances glenohumeral stability. In clinical and laboratory settings, we have shown that posteroinferior shoulder instability is associated with both capsular laxity and well-defined pathological lesions of the glenolabral concavity. Our results indicate that arthroscopic posterior capsulolabral repair and augmentation is a useful tool to restore the depth of the glenolabral concavity and to reduce the redundant posteroinferior capsule. This technique is effective in treating posteroinferior instability.     

Capsular Tear in Line With the Inferior Glenohumeral Ligament: A Cause of Anterior Glenohumeral Instability in 2 Patients

Anterior glenohumeral instability typically involves lesions associated with the inferior glenohumeral ligament complex. Multiple lesions have been described in this setting, including Bankart, humeral avulsion of the inferior glenohumeral ligament complex, and mid-substance capsular tears. These lesions are indicative of the high-force traumatic nature of anterior shoulder dislocation. Two cases of recurrent anterior shoulder instability are presented with a capsular tear perpendicular to the usual orientation and not consistent to the amount of force involved in a dislocation. Arthroscopy revealed a capsular defect from the glenoid to the humeral head in the anterior inferior glenohumeral ligamentous complex in both. This lesion is an unusual circumstance, providing another pathology to include in the differential diagnosis of anterior glenohumeral instability.     

Arterial supply of the glenoid: an anatomic study

Surgery is performed on the glenoid for a variety of pathologic conditions, and an adequate blood supply is required to achieve good healing of soft tissue and bone. The objective of this investigation was to study the arterial supply of the glenoid in 24 fresh human cadaveric specimens. The vascular supply originates from branches of the anterior and posterior circumflex arteries and the suprascapular artery and branches directly from the infraspinatus and teres minor muscles. The antero-superior portion of the glenoid is poorly vascularized, with a specific area that is completely devoid of blood supply. In addition, circumferentially around the glenoid rim, there is an area of approximately 5 mm from the edge that is completely devoid of vascularity. Adequate bone and soft-tissue healing in the glenoid, particularly in its anterosuperior portion, after fracture repair, osteotomy, total shoulder arthroplasty, and capsular procedures may be compromised by the demonstrated hypovascularity.     

Arthroscopic Technique of Interposition Arthroplasty of the Glenohumeral Joint

Arthroscopic glenohumeral interposition arthroplasty is performed with the patient placed in the lateral decubitus position. Standard posterior, anterior, and anterosuperior portals are created, a routine diagnostic arthroscopy is performed, and the joint is débrided with the use of an arthroscopic shaver. An arthroscopic burr is used to resect prominent osteophytes, to alter the version of the glenoid if necessary, and to create microfractures on the glenoid surface. Next, 3 absorbable sutures are passed percutaneously with a 30° angled suture grasper from 3 different sites posteriorly through the posterior capsular–labral tissue and into the anterior portal cannula, where they are isolated by means of the suture saver kit. The prepared interposition membrane/tissue (GRAFTJACKET Regenerative Tissue Matrix, Wright Medical Technology, Inc., Arlington, TN) is tagged with the 3 sutures in the anterior cannula before it is introduced into the joint. Three additional sutures are attached to the membrane anteriorly at 1, 3, and 5 o’clock positions and are isolated with suture savers. The membrane is next introduced into the joint through the anterior cannula and is aligned with the glenoid rim. The anterior sutures are rerouted through the anterior capsular–labral tissue with a 70° angled suture grasper, and they are retrieved through the anterior cannula. Intra-articular nonsliding knots are used anteriorly to anchor the interposition tissue to the anterior glenoid labrum and capsule. The posterior sutures are knotted intra-articularly, or they may be tied extra-articularly; the proximal and distal posterior sutures are retrieved subcutaneously out through the skin tract of the posterior portal and are knotted with the suture present in this portal, with the use of nonsliding knots. Stability of the interposition tissue is assessed by movement of the glenohumeral joint through its entire range of motion. The postoperative protocol consists of early passive exercises, active exercises after 3 weeks, and muscle-strengthening exercises after 6 weeks.     

关节镜下手术治疗创伤性肩关节前不稳定

目的探讨关节镜下手术治疗创伤性肩关节前不稳定的治疗原则、操作要点以及临床效果。方法2002年9月至2005年5月,本组患者18例,其中运动伤12例,工伤5例,交通伤1例。受伤至就诊时间平均15周。临床表现为肩痛18例,肩活动受限15例。前惧痛征(apprehension)阳性18例;肱二头肌牵拉征(speed)阳性5例;X线出现Hill-Satchs征3例。气-碘双重对比造影CTⅠ度1例,Ⅱ度15例,Ⅲ度2例。手术情况镜下见前盂唇撕脱18例,前关节囊松弛4例,合并上方盂唇撕裂(SLAP损伤)4例,游离体3例,盂唇骨赘形成2例,肱骨头、肩胛盂软骨剥脱2例;分别给予关节镜下前盂唇缝合锚钉固定(18例),前关节囊松弛紧缩术(3例),肱二头肌腱刨削(2例),关节囊外重新附着固定(2例),上盂唇缝合(3例),刨削(1例)等处理。术前UCLA肩关节评分(14±3)分。结果18例患者平均随访18个月(10~32个月)。所有患者肩部疼痛消失。1例于剧烈活动后肩部酸困感。肩部活动受限3例,其中后伸受限10°1例,肩外旋受限2例(<20°),前惧痛征1例有轻度不适,余体征均为阴性。所有患者恢复原工作、运动。术后UCLA肩关节评分(32±5)分,与术前比较差异有统计学意义(t=14.081,P<0.01)。结论关节镜下治疗创伤性肩关节前不稳定可取得良好效果。熟练操作技术,准确判定前盂唇充分松解及复位、固定,并正确处理合并损伤十分重要。带线锚钉固定前盂唇可靠,操作简便。     

Surgical anatomy of the posterior shoulder: effects of arm position and anterior-inferior capsular shift.

The purposes of this study were to evaluate anatomically various surgical intervals to the posterior shoulder and to determine the effects of varying arm positions and anterior-inferior capsular shift (AICS) on the relation of the posterior neurovascular structures to fixed bony landmarks. Fourteen cadaveric shoulders were dissected. The posterior surgical anatomy was defined, and the distances from fixed bony landmarks to neurovascular and musculotendinous structures were determined with digital calipers. Measurements were made with the arm in various positions and repeated after AICS. The most direct anatomic approach to the posterior shoulder was through a deltoid split in the raphe from the posterolateral corner of the acromion (PLCA), followed by an infraspinatus (IS) splitting incision. The IS/teres minor interval was at the inferior aspect of the glenoid rim and was difficult to locate in all specimens. The distance to the axillary nerve from the PLCA averaged 65 mm and decreased by an average of 14 mm (22%) with abduction and by 19 mm (29%) with extension. The posterior humeral circumflex artery was located along the humeral neck and was vulnerable to injury during lateral capsular dissection. The suprascapular nerve had multiple branches to the IS with most penetrating the muscle at its inferior portion. The closest branch to the glenoid rim was an average of 20 mm medial from it. No branch entered at the level of the IS raphe. The anatomic relations of the suprascapular nerve were unchanged after AICS. On the basis of this study, surgical exposure of the posterior shoulder with a deltoid split from the PLCA, followed by an IS split, appears to be anatomically safe. The arm position should be in neutral rotation, especially if previous anterior capsular procedures have been performed, which can alter the posterior neurovascular anatomic relations.     

Posterior Chondrolabral Cleft: Clinical Significance and Associations with Shoulder Instability

Background

A high signal intensity cleft between the labrum and articular cartilage of the posterior glenoid is commonly visible on MRI and has been suggested to be anatomic variation [3, 10, 23]. The association of a posterior cleft with variations in glenoid morphology or with shoulder instability is unknown.

Questions/Purposes

The purposes of this study were to determine if posterior chondrolabral clefts are associated with variations in glenoid morphology, and to determine if they are associated with shoulder instability.

Patients and Methods

Shoulder MRI was performed in 1,264 shoulders, 1,135 male (89.8%), and 129 female (10.2%). A musculoskeletal radiologist blinded to history and outcomes evaluated the MR images for linear high signal intensity at the posterior chondrolabral junction and a rounded or truncated contour of the posterior glenoid. Glenoid version and depth were measured. Patients were followed prospectively for shoulder instability for 4 years. Univariate and multivariate statistical analysis were performed.

Results

Posterior chondrolabral cleft was present in 114/1,264. Posterior chondrolabral cleft was associated with a rounded or truncated posterior glenoid. There were 9.5° retroversion in shoulders with a posterior cleft, and 7.7° retroversion in shoulders without a cleft. Shoulders with a posterior chondrolabral cleft were more likely to develop shoulder instability.

Conclusions

Posterior chondrolabral clefts are not uncommon on MRI. They are associated with a rounded or truncated posterior glenoid and a small but significant increase in glenoid retroversion. They are associated with shoulder instability.     

A new technique of arthroscopic capsular shift in anterior shoulder instability

We describe a new arthroscopic technique to reinforce the torn inferior glenohumeral ligament (IGHL) and the elongated capsule to the glenoid rim. The arthroscope is inserted over the superior portal and, after the insertion of a suture anchor, both limbs are pulled out over the posterior portal. The IGHL is grasped and pulled upward onto the glenoid rim using a suture retriever clamp inserted over the posterior portal. A 45° curved blunt clamp (Sidewinder; Arthrex, Naples, FL) coming from the anterior penetrates the IGHL, and 1 end of the suture limb is given into the branches of the clamp and pulled out anteriorly. After a second perforation of the capsule, a horizontal suture creating a neolabrum can be placed. This technique allows a suitable reinforcement of the capsule without intraoperative complications. In cases of capsular elongation, especially a torn IGHL, the capsular instability can be addressed by the described Sidewinder technique. More sophisticated arthroscopic techniques such as this will increase the indication for arthroscopic shoulder stabilization.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 4 (April), 2001: pp 426–429     

肩关节后方不稳的诊疗现状

肩关节后方不稳发生率明显低于前方不稳,但是临床上诊疗难度大,误诊和漏诊率较高。其病因、临床表现治疗策略与前方不稳完全不同。因此,深入认识肩关节周围解剖结构、掌握检查方法、基于解剖和受伤方式对肩不稳进行分型对提高诊断准确率具有关键作用。CT三维重建对肱骨头及肩盂骨缺损的评估和核磁共振造影(magnetic resonance angiography,MRA)对于后方盂唇及关节囊病变评估有助于精确诊断。治疗方法分为保守治疗及手术治疗。对肌性不稳建议保守治疗。创伤性及发育不良性不稳建议手术治疗,具体根据肩盂侧或肱骨头侧损伤行不同术式。肩盂侧损伤根据骨缺损情况行软组织手术、植骨手术或截骨手术来重建后方稳定结构;肱骨头侧缺损则根据前方骨缺损面积行植骨术或肩胛下肌填塞术。手术方式有开放手术和关节镜手术,前者优势在于学习曲线短,固定牢固;后者优势在于微创操作及可以多角度观察病变部位并精确控制骨块位置。本文对将上述问题加以综述。     

Anatomy, histology, and vascularity of the glenoid labrum. An anatomical study.

We studied the gross, histological, and vascular anatomy of the glenoid labrum in twenty-three fresh-frozen shoulders from cadavera to demonstrate its cross-sectional anatomy, its microvascularity, and its attachments. The superior and anterosuperior portions of the labrum are loosely attached to the glenoid, and the macro-anatomy of those portions is similar to that of the meniscus of the knee. The superior portion of the labrum also consistently inserts directly into the biceps tendon, while its inferior portion is firmly attached to the glenoid rim and appears as a fibrous, immobile extension of the articular cartilage. The arteries supplying the periphery of the glenoid labrum come from the suprascapular, circumflex scapular, and posterior circumflex humeral arteries. In general, the superior and anterosuperior parts of the labrum have less vascularity than do the posterosuperior and inferior parts, and the vascularity is limited to the periphery of the labrum. Vessels supplying the labrum originate from either capsular or periosteal vessels and not from the underlying bone.     

Posteroinferior glenoplasty can change glenoid shape and increase the mechanical stability of the shoulder.

The treatment of recurrent posterior glenohumeral instability remains an unsolved clinical problem. Although various types of capsulorraphy have been advocated, outcome studies indicate that it is difficult to achieve a balance between stability and mobility. Alterations of the bony glenoid for posterior instability have been proposed, but are not well understood from a mechanical perspective. This investigation had 2 purposes: (1) to determine in a cadaver model if posteroinferior glenoplasty can change the shape of the glenoid, and (2) to determine if altering the shape of the glenoid can increase the mechanical stability of the glenohumeral joint. We determined the effective glenoid shape in 7 normal cadaver glenoids by tracking the path of the center of the humeral head as it was translated across the glenoid face in 8 different directions. These determinations enabled us to calculate the maximum effective slope of the glenoid in each direction. We then determined the mechanical stability of the glenoids in each of the 8 directions by measuring the tangential force required to dislocate the shoulder under a 50-N compressive load. The ratio of the dislocating force to the compressive load was defined as the stability ratio. All measurements were repeated after a standardized posteroinferior glenoplasty was performed. Posteroinferior glenoplasty increased the posteroinferior glenoid depth from 3.8 +/- 0.6 mm to 7.0 +/- 1.8 mm and shifted the center of the humeral head an average of 2.2 mm anteriorly and 1.8 mm superiorly. These changes in dimension could be directly visualized as an immediate mechanical consequence of the glenoplasty procedure, particularly because of the insertion of the bone wedge. Glenoplasty increased the posteroinferior glenoid slope from 0.55 +/- 0.07 to 0.83 +/- 0.12 and increased the posteroinferior stability ratio from 0.47 +/- 0.10 to 0.81 +/- 0.17. This is a more than 70% increase in the tangential force that can be resisted before dislocation. The increase can be quantitatively understood as a direct mechanical consequence of the altered shape of the glenoid concavity. These numbers indicate that, in this cadaveric model, posteroinferior glenoplasty results in defined changes in the effective glenoid shape and in the mechanical stability of the glenohumeral joint. However, this study does not establish the role of this procedure in the clinical management of posterior glenohumeral instability.     

Combined Posterior Bankart Lesion and Posterior Humeral Avulsion of the Glenohumeral Ligaments Associated With Recurrent Posterior Shoulder Instability

Recurrent posterior glenohumeral instability is uncommon and is often misdiagnosed. Damage to the posterior capsule, posteroinferior glenohumeral ligament, and posterior labrum have all been implicated as sources of traumatic posterior instability. We describe a case of traumatic recurrent posterior instability resulting from a posterior Bankart lesion accompanied by posterior humeral avulsion of the glenohumeral ligaments. The Bankart lesion was repaired using a single arthroscopic suture anchor at the glenoid articular margin. The posterior humeral avulsion of the glenohumeral ligaments was addressed with 3 suture anchors placed at the capsular origin at the posterior humeral head. Using these anchors, the posterior capsule was advanced laterally and superiorly for a secure repair. Arthroscopic anatomic reconstruction of both lesions resulted in an excellent clinical outcome.     

Arthroscopic "Cuff-Sparing" Percutaneous (CUSP) Technique for Posterior Instability Repair in the Beach-Chair Position

Arthroscopic posterior labral repair and capsular shift procedures are technically difficult in the beach-chair position as compared with the lateral decubitus position. Optimal visualization in the beach-chair position, and anchor placement in the posterior glenoid rim, necessitate various lateral trans-cuff portals, and these may result in damage to the rotator cuff tendons. The author has devised a new technique for posterior labral repair in the beach-chair position; the technique involves visualization of the posterior capsulolabral complex through a 70-degree arthroscope placed in the posterior axillary pouch portal, and labral repair is performed through percutaneous medial portals. The cuff-sparing and percutaneous (CUSP) nature of the technique utilizes safe anatomic zones for visualization and percutaneous repair of the entire posterior labrum, and lateral portals that may potentially damage the rotator cuff tendons are avoided. Technical variants of the procedure include: (1) a "CUSP shift" technique (combined labral repair and capsular shift); (2) a "CUSP-stitch" technique (isolated labral repair without a capsular shift); and (3) a "posterior labroplasty" technique for reconstruction of deficient posterior labral tissue. Technical tips to avoid neurological injury, and a detailed rehabilitation protocol are presented.     

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.     

Superior Bennett Lesion: A Bone Fragment at the Posterosuperior Glenoid Rim in 5 Athletes

In throwing athletes, a Bennett lesion is a bony spur that usually forms at the posteroinferior glenoid rim and sometimes becomes painful. We encountered superior Bennett lesions in the shoulders of 5 athletes, which were detected at the posterosuperior glenoid rim as a separate bone fragment. In all 5 athletes this lesion appeared to be the main cause of shoulder pain during throwing or overhead activity. The lesions were easily visualized on plain radiographs (axial view, scapular Y view, and 45° craniocaudal view) or computed tomography scans. Tenderness was detected over the posterior aspect of the glenohumeral joint, the pain provocation test specific for SLAP lesions was positive, and posterior shoulder pain was elicited by forced external rotation at 90° of abduction in all 5 cases. The pain was diminished or decreased by injection of local anesthetic around the lesion. At arthroscopy, detachment of the posterosuperior labrum and posterior capsular tightness were detected in all 5 cases. Through the detached portion of the posterosuperior labrum, we could easily reach an unstable mobile bone fragment, which was resected arthroscopically. Although the pathologic mechanism is unclear, the mobility of the bone fragment appeared to be related to the occurrence of symptoms.     

Operative results of the inferior capsular shift procedure for multidirectional instability of the shoulder

BACKGROUND: Neer and Foster previously described the inferior capsular shift procedure for treating multidirectional instability of the shoulder and reported preliminary results that were quite satisfactory. The purpose of our study was to perform a longer-term follow-up evaluation of the efficacy of the inferior capsular shift procedure for treating multidirectional instability of the shoulder. METHODS: An inferior capsular shift procedure was used to treat multidirectional instability of the shoulder in forty-nine patients (fifty-two shoulders). All patients had failed to respond to an exercise program. In this series, the operative approach (anterior or posterior) was based on the major direction of the instability, as determined by the preoperative history and physical examination and as verified by examination with the patient under anesthesia. In all of the patients, the inferior capsular shift was the primary attempt at operative stabilization. The repair consisted of a lateral-side (or humeral-side) shift of the capsule to reduce capsular redundancy and, when necessary, a reattachment of the avulsed labrum to the anteroinferior aspect of the glenoid. RESULTS: A redundant capsular pouch was seen in all of the shoulders in this series. In addition, detachment of the anteroinferior aspect of the labrum was found in ten shoulders and an anterior fracture of the glenoid rim was seen in two shoulders. At an average of sixty-one months (range, twenty-four to 132 months), results were available for forty-nine shoulders (forty-six patients). Thirty shoulders (61 percent) had an excellent overall result, sixteen (33 percent) had a good result, one (2 percent) had a fair result, and two (4 percent) had a poor result. Forty-seven (96 percent) of the forty-nine shoulders remained stable at the time of follow-up. Two of the thirty-four shoulders that had been repaired through an anterior approach began to subluxate anteroinferiorly again. None of the fifteen shoulders that had been repaired through a posterior approach had recurrent instability. Full function, including the ability to perform strenuous manual tasks, was restored to forty-five shoulders (92 percent). A return to sports was possible after thirty-one (86 percent) of the thirty-six procedures done in athletes; however, a return to the premorbid level of participation was possible after only twenty-five (69 percent) of the thirty-six procedures. CONCLUSIONS: The results in this series demonstrate the efficacy and the durability of the results of the inferior capsular shift procedure for the treatment of shoulders with multidirectional instability. The procedure directly addresses the major pathological feature - a redundant joint capsule. Similar results were seen with either an anterior or a posterior approach, and we continue to approach shoulders with multidirectional instability on the side of greatest instability. A postoperative brace was reserved for patients in whom a posterior approach had been used or in whom an anterior approach had involved extensive posterior capsular dissection (ten of the thirty-four shoulders treated with the anterior approach).     

Posterior shoulder instability following anatomic total shoulder arthroplasty: A case report and review of management

We report a case of posterior shoulder instability following anatomic total shoulder arthroplasty (TSA). In addition, we present guidelines to aid in the management of posterior instability after TSA. A 50-year-old male underwent anatomic TSA for glenohumeral osteoarthritis. Postoperatively, the patient developed posterior instability secondary to glenoid retroversion. He did not improve despite conservative treatment. He underwent an arthroscopic posterior bone block procedure, 4-month after his index arthroplasty. At 14-month follow-up, the patient had regained near full motion and strength, and radiographs demonstrated osseous integration with no evidence of component loosening. Posterior instability following TSA is a relatively rare complication and challenging to manage. The posterior, arthroscopic iliac crest bone block grafting procedure represents a treatment option for posterior instability in the setting of a stable glenoid prosthesis following TSA.