Postimpingement instability following reverse shoulder arthroplasty: a parametric finite element analysis

BackgroundInstability following reverse shoulder arthroplasty is influenced by various factors such as component design, component positioning, and soft tissue tensioning. Patients may achieve glenohumeral motion beyond initial scapular impingement during activities of daily living which could further compound instability. However, instability/subluxation risk postscapular impingement is not well documented. Conventional range of motion analysis tools cannot account for the restraining effect of soft tissues or subluxation risk after impingement. Using a previously validated finite element analysis approach, the purpose of this study was to investigate the effects of glenoid component lateralization and humeral component angle of inclination (AOI), with or without simulated subscapularis repair, on postimpingement subluxation. We hypothesized that lack of subscapularis repair, a valgus humeral component AOI, and glenoid medialization would all result in greater postimpingement instability.MethodsA FE model of the shoulder including the subscapularis tendon and middle deltoid was created, incorporating a general representation of a commercial reverse shoulder arthroplasty implant placed under the direction of a fellowship-trained shoulder surgeon. The deltoid and subscapularis were tensioned and wrapped around the reconstructed glenohumeral joint prior to simulating motion. Humeral rotations were then prescribed to simulate external rotation (neutral to 50°), extension (neutral to 50°), adduction (neutral to 30°), and abduction (neutral to 90°). The effects of three glenosphere lateralization offsets (2, 4, and 10 mm) and 2 humeral liner angles of inclination (varus-150° and valgus-155°) on subluxation propensities were investigated with and without the subscapularis tendon present.ResultsSimulated subscapularis repair resulted in 21%-34% less postimpingement subluxation. Presence of the subscapularis provided stability over a greater range of abduction. Impingement-free range of motion was similar regardless of the presence or absence of the subscapularis. The valgus AOI resulted in 23% less subluxation during abduction. During other motions however, the valgus AOI resulted in 67%-110% greater postimpingement subluxation (subscapularis present), which further worsened without the subscapularis.ConclusionImplant design modifications to improve stability may not be beneficial for all motions, highlighting the importance of directionality when investigating instability. Liner-bone impingement appears to compound instability/subluxation and the subscapularis appears to restrain postimpingement instability.Level of evidenceBasic Science Study; Computer Modeling     

The clinical outcomes and tuberosity healing after reverse total shoulder arthroplasty for acute proximal humeral fracture using the turned stem tension band technique

BackgroundRecent studies have reported the clinical effectiveness of tuberosity healing after reverse total shoulder arthroplasty in patients with proximal humeral fractures with respect to joint stability, long-term survival, and postoperative range of motion. However, it is challenging to achieve robust fixation of the fragile bone fragments in elderly patients. This study aimed to report on the radiographic and clinical outcomes of patients who underwent reverse total shoulder arthroplasty for acute proximal humeral fractures using a Turned stem Tension Band technique–a simple suture configuration that can apply a compressive force on both tuberosities at the same time.MethodsEighteen patients who underwent reverse total shoulder arthroplasty for complex proximal humeral fractures (age 80.4 ± 4.7 years, range 70–87 years), using our Turned stem Tension Band technique, were included in this study and evaluated postoperatively for range of motion, American Shoulder and Elbow Surgeons score, Numerical Rating Scale, and tuberosity healing, with minimum 2-years follow-up (mean 34.5 months, range 24–60 months).ResultsAt the final follow-up, mean range of motion results were active flexion, 119 ± 34°; active abduction, 116 ± 35°; active external rotation, 27 ± 12°; and active internal rotation, L3. Six of 11 (55%) patients with 4-part dislocated fractures had neurological disorders from the time of injury; of these, three patients obtained shoulder elevation under 90° at the final follow-up. The mean American Shoulder and Elbow Surgeons score was 77.3 ± 10.7, and the mean Numerical Rating Scale was 1.2 ± 0.9. Fifteen of 18 (83%) patients were satisfied with the results. The tuberosity healing rate was 100% (18 of 18).ConclusionsThe Turned stem Tension Band technique in reverse total shoulder arthroplasty for proximal humeral fractures provides a robust fixation, regardless of the fracture pattern, which results in a high tuberosity healing rate.     

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.     

Intraoperative joint load evaluation of shoulder postures after reverse total shoulder arthroplasty: a cadaveric study using a humeral trial sensor

BackgroundThe effect of improper tension in reverse total shoulder arthroplasty (RTSA) can cause both joint looseness potentially leading to instability and dislocation and joint tightness potentially leading to limited joint motion and acromial or scapular spine stress fractures. Intra-articular load sensors offer an innovative technology providing information on real-time joint load parameters. The objective of this study is to evaluate a novel load sensor in a cadaveric RTSA model, to measure joint loads in shoulder positions required for activities of daily living (ADLs), with and without subscapularis repair. Our hypothesis is that an in situ joint load sensor can reliably measure the magnitude of joint load, and that subscapularis repair both increases joint load magnitude and improves the concentricity of the articulation at end range motion.MethodsNine freshly frozen full body cadaver shoulders were selected for this study. All shoulders were implanted with RTSA implants with the humeral insert incorporating a wireless load measuring sensor. Three ADL postures (“across chest”, “behind back”, and “overhead reach”) were each evaluated 5 times by a single observer that was blinded to the real time loads displayed by the sensor software interface. Joint load magnitude and resultant location of the load (centroid) were recorded for each ADL posture. The subscapularis was then repaired in the native location, and the ADL posture and load measurement protocol were repeated.ResultsAll 3 postures demonstrated an intra-class correlation coefficient of over 0.9, indicating high repeatability of the load magnitude measured on the same specimen. Load magnitudes ranged from 5 lbf to 70 lbf “where 1lbf = .454kgf” depending on the posture and position. Subscapularis repair statistically significantly increased mean joint loads in the behind back position (P = .046) and the “overhead reach” posture (P < .001). The centroid location differed between the “behind back” and “overhead reach” postures for both radial distance (R) and angular position (θ) (P < .05). Subscapularis repair did not change R or theta for any of the three ADL postures compared to testing with subscapularis unrepaired.DiscussionSensors placed within the trial insert can reliably measure joint loads in selected ADL postures. Subscapularis tendon repair increases the magnitude of joint load but does not appear to improve concentricity of resultant load when the shoulder is placed in ADL postures. Future work will involve sensor usage in a clinical setting to evaluate if measured joint load parameters correlate with improved clinical outcomes.Level of EvidenceBasic Science Study; Biomechanics     

反肩置换在老年肱骨近端内固定失败翻修术中的疗效观察

目的：探讨反肩置换术在老年肱骨近端骨折内固定失败后翻修中的应用价值和效果。方法 ：回顾性分析2014年5月至2020年3月肱骨近端骨折内固定失败的患者8例,其中男3例,女5例;年龄65～75岁。8例均行反式肩关节置换术,病程8～16个月。记录并比较手术前和末次随访的关节活动度（range of motion,ROM）、加州大学（University of California at Los Angeles,UCLA）肩关节评分、肩关节视觉模拟评分（visual analogue scale,VAS）、焦虑自评量表（self-rating anxiety scale,SAS）评分、肩关节功能Constant-Murley评分,并分析手术并发症情况。结果：术后8例均获得随访,时间16～28个月。患肩关节活动度（前屈、外旋、外展、内旋）术后明显改善,术后VAS、SAS和UCLA评分也得到改善。肩关节功能Constant-Murley评分中末次随访疼痛、日常活动、活动范围、力量测试评分比术前均有明显提升,且总分比术前提高。1例发生肩胛盂切迹,影像学显示分级为1级,其余患者未发生相关特异性和非特...     

Reverse shoulder arthroplasty for deltoid-deficient shoulder following latissimus dorsi flap transfer. Case report

IntroductionThe usual indication for reverse shoulder arthroplasty is glenohumeral arthritis with inadequate rotator cuff and intact deltoid muscle. We report here a case of reverse shoulder arthroplasty using a lattisimus dorsi flap in a patient with deltoid-deficient shoulder following a gunshot injury.Presentation of the caseThe patient was an otherwise healthy 51-year-old male with a history of gunshot injury of the left shoulder 2006. Upon presentation in 2011, the patient had a loss of most of his shoulder bony and muscular structures. Due to deltoid muscle deficiency, the patient underwent Lattisimus Dorsi muscle flap followed by reverse shoulder arthroplasty in order to establish an upper limb function.Upon discharge, 11 days after the surgery, the patient was able to achieve 150° flexion and 90° abduction while in the supine position and 45° in each direction, while sitting. He was able to perform internal rotation (behind back) up to the level of the L1 vertebra, assisted active abduction of 90°, and external rotation of 20°. Power tests showed power of grade 4/5 for both shoulder flexion and extension and grade 2+/5 for both abduction and adduction.At the last follow up one year after the operation, The patient still had passive pain-free full range of motion, but no progress in active range of motion beyond that upon discharge.ConclusionReverse shoulder arthroplasty after Latissmus dori flap in patient with deltoid deficient shoulders can be a successful and reproducible approach to treat such conditions.     

A network meta-analysis of multiple modalities for the treatment of complex proximal humeral fractures in older adults

ObjectiveFour principal treatment modalities are applied to treat complex proximal humeral fractures in older adults: conservative treatment, open reduction internal fixation, hemiarthroplasty, and reverse shoulder arthroplasty. However, among these, the optimal treatment modality has yet to be determined. Therefore, a network meta-analysis was carried out to compare treatment modalities and assess their effectiveness.MethodsThe databases PUBMED, EM-BASE, the Cochrane Central Register of Controlled Trials, Web of Science, and CNKI were searched for randomised controlled trials on complex proximal humeral fractures in older people, ranging from inception of each database to May 2023.ResultsThis meta-analysis included 14 randomised controlled trials, containing 791 patients aged over 60 years who were treated for complex proximal humeral fractures. Reverse shoulder arthroplasty and hemiarthroplasty yielded the highest Constant shoulder scores, whilst conservative treatment performed poorly. Hemiarthroplasty and open reduction internal fixation yielded the best performances on the visual analogue pain scale, whilst conservative treatment performed poorly. Reverse shoulder arthroplasty and open reduction internal fixation allowed for maximum forward flexion and outreach of range of motion, whilst hemiarthroplasty allowed for the least. Open reduction internal fixation and reverse shoulder arthroplasty allowed for maximum internal rotation of the range of motion, whilst conservative treatment allowed for the least. Hemiarthroplasty and conservative treatment allowed for maximum external rotation of the range of motion, whilst open reduction internal fixation allowed for the least.ConclusionCompared with open reduction internal fixation, reverse shoulder arthroplasty yields better Constant shoulder scores and allows for greater forward flexion and outreach of range of motion of the shoulder joint in complex proximal humerus fractures in older patients. Meanwhile, hemiarthroplasty yields the best visual analogue scale scores and allows for maximum external rotation of the range of motion. However, open reduction with internal fixation remains the preferred clinical treatment for complex proximal humeral fractures in older patients.     

Muscle and joint‐contact loading at the glenohumeral joint after reverse total shoulder arthroplasty

The purposes of this study were to determine the contributions of each shoulder muscle to glenohumeral joint force during abduction and flexion in both the anatomical and post‐operative shoulder and to identify factors that may contribute to the incidence of glenoid component loosening/failure and joint instability in the shoulder after reverse shoulder arthroplasty (RSA). Eight cadaveric upper extremities were mounted onto a testing apparatus. Muscle lines of action were measured, and muscle forces and muscle contributions to glenohumeral joint forces were determined during abduction and flexion of the pre‐operative anatomical shoulder and of the shoulder after arthroplasty. Muscle forces in the middle deltoid during abduction and those in the middle and anterior deltoid during flexion were significantly lower in the reverse shoulder than the pre‐operative shoulder (p < 0.017). The resultant glenohumeral joint force in the reverse shoulder was significantly lower than that in the pre‐operative shoulder; however, the superior shear force acting at the glenohumeral joint was significantly higher (p < 0.001). Reverse total shoulder arthroplasty reduces muscle effort in performing lifting and pushing tasks; however, reduced joint compressive force has the potential to compromise joint stability, while an increased superior joint shear force may contribute to component loosening/failure. Because greater superior shear force is generated in flexion than in abduction, care should be taken to avoid excessive shoulder loading in this plane of elevation. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1850–1858, 2011     

反球型人工肩关节置换术治疗合并肩袖损伤的老年粉碎性肱骨近端骨折

目的:探讨采用反球型人工肩关节置换术治疗老年粉碎肱骨近端骨折的临床疗效。方法:自2017年1月至2017年12月治疗12例老年粉碎性肱骨近端骨折或骨折-脱位患者,根据术前MRI检查以及术中直视下检查确认肩袖损伤诊断,采用反球型人工肩关节假体置换手术治疗。其中男7例,女5例;年龄65～86岁;左侧受累5例,右侧受累7例。观察患者肩关节活动度及术后并发症情况,采用VAS评分评价疼痛缓解程度,并采用UCLA评分评价肩关节功能恢复情况。结果:12例患者术后获得随访,时间8～18个月。末次随访时患者肩关节活动度:前屈上举90°～150°,外旋为5°～30°,内旋平均为L_3水平(S_1水平～L_1水平)。VAS疼痛评分为0～6分,UCLA评分为18～32分,其中良5例,差7例。所有患者术后均无感染、假体松动、肩峰应力骨折、神经血管损伤等并发症发生。结论:合并肩袖损伤的老年粉碎肱骨近端骨折采用反球型人工肩关节置换术治疗,术后早期肩关节活动范围恢复良好,疼痛较轻,患者满意度高。     

Glenohumerale Arthrolyse der Omarthroseschulter bei anatomischer Schulterprothesenimplantation

Aim of the operation

Pain reduction and improvement of range of motion.

Indications

Primary and secondary osteoarthritis, unsuccessful conservative treatment, limited range of motion with capsular contraction.

Contraindications

General contraindications for anatomical total shoulder arthroplasty. Instability arthritis without capsular contraction.

Operative technique

Deltopectoral approach. Detachment and release of the subscapularis tendon at the lesser tuberosity, incision of the anterior and inferior humeral sided capsule and osteophyte removal, humeral head resection and stem preparation. Glenoid exposure, capsular an labral resection. Glenoid surface preparation and prosthetic component implantation. Anatomical placement of the the humeral head without overstuffing. Implantation of the final humeral stem. Transosseous refixation of the subscapularis tendon. Wound closure.

Follow-up treatment

Abduction brace for 4 weeks. Assisted motion starting the first postoperative day during the first 6 weeks: anteversion/ retroversion 90-0-0°, abduction/ adduction 90-0-20°, internal/external rotation 90-0-individual limitation. Subsequent development of full range of motion.

Results

In 2009 and 2010 anatomical total shoulder arthroplasty with glenohumeral arthrolysis was performed in 53 cases. At an average follow up of 32 months the Constant score and range of motion improved significantly. The complication rate was 9%.     

The extended humeral osteotomy for revision shoulder arthroplasty: Results and technique

BackgroundExtraction of a well-fixed humeral stem during revision shoulder arthroplasty is challenging and can result in significant proximal humeral destruction. We introduce a refinement to osteotomy techniques, the extended humeral osteotomy (EHO), that facilitates complete extraction of the humeral component and cement mantle.Materials and methodsTwenty-five patients with failed shoulder arthroplasty who underwent an EHO for removal of a well-fixed humeral component between December 2008 and May 2018 were retrospectively identified. Twenty patients were available for final follow-up. Records and radiographs were reviewed for intraoperative and postoperative complications, preoperative and postoperative function, and patient reported outcome measures.ResultsAverage follow-up was 65.6 months. All osteotomies healed. Of patients who were converted to reverse shoulder arthroplasty, 18/19 remained stable at final follow-up. From preop to final follow-up, mean forward elevation improved from 77° to 109° (p-value 0.013), ASES scores improved from 33.9 to 59.5 (p-value 0.003), and VAS scores improved from 6 to 3.1 (p-value 0.002). Complications related to the osteotomy occurred in two patients (10%). In one patient, the osteotomy was performed using improper instrumentation and created an intraoperative periprosthetic fracture which required immediate plate fixation. In one patient, irritation from a cable required cable removal at 1 year postop. There were no iatrogenic nerve injuries or known recurrent infections.ConclusionThe extended humeral osteotomy is a safe and reproducible technique for complete extraction of well-fixed humeral prostheses and associated cement mantles in revision shoulder arthroplasty cases.Level of evidenceLevel IV; Case Series; Treatment Study     

Axillary nerve proximity to the humeral guide pin during stemless total shoulder arthroplasty

BackgroundThe proximity of the axillary nerve to the humeral head guide pin has not been described in current literature. Therefore, we aimed to elucidate the anatomical relationship through a cadaveric study.MethodsTen fresh-frozen cadaveric specimen were included in this study. The standard deltopectoral approach was utilized for appropriate exposure. The subscapularis and the long head of the biceps tendon were tenotomized to access the glenohumeral joint. Humeral head cut was then visually performed with humeral sizing and positioning. A Steinmann Pin was placed and advanced into the lateral cortex. Following dissection and visualization, the distance from the axillary nerve to the point of lateral humeral cortex was measured.ResultsOn average, the axillary nerve was found 7.2 ± 3.1 mm from the tip of the Steinmann Pin at the level of the lateral humeral cortex and distal to the site of cortical penetration.DiscussionSurgeons should be aware of the relationship between the axillary nerve and the humeral guide pin, and care should be taken to protect the axillary nerve during piercing of the lateral humeral cortex during pin placement. This relationship continues to be of importance, even with evolving stemless implant systems in total shoulder arthroplasty.     

The glenohumeral offset ratio: A radiographic study

A systematic method of component selection for total shoulder arthroplasty is needed. The method must take into account the soft-tissue constraints of a degenerative joint and optimize joint biomechanics by placing the joint line in the best possible position. The purpose of our study was to determine radiographically the normal glenohumeral joint line position based on a ratio of distances between the joint line and fixed landmarks on the humerus and scapula. We studied modified anteroposterior radiographs of the glenohumeral joint in 86 volunteers (51 men and 35 women; ages ranging from 21 to 47 years). Two measurements were made on each radiograph: (1) the perpendicular distance from the most medial portion of the glenoid to the inferior base of the coracoid process at its attachment to the scapular blade, and (2) the perpendicular distance from the midline of the humeral shaft to the most medial point on the humeral head. The joint line position was described as the ratio of the glenoid measurement to the sum of the two measurements (i.e., the glenohumeral offset ratio). The validity and reliability of glenoid offset measurements were determined by comparing radiographic and anatomic measurements of glenoid offset in cadaveric human scapulae. Radiographs were made with rotational error to determine its effects on the measurement of humeral offset. Humeral offsets and glenoid thicknesses of five different total shoulder systems were then determined from template overlays. The mean glenohumeral offset ratio was 0.31 (range 0.18 to 0.39). We detected no significant difference in the ratio between men and women volunteers. There was close agreement between radiographie and direct (anatomic) measurements of glenoid offset in cadaveric scapulae. Values for humeral offset were not significantly affected by radiographic rotational error. The evidence indicates that a fairly constant glenohumeral offset ratio in normal shoulders can be reliably calculated from a single radiograph. In addition to the prosthesis specifications, we suggest that the glenohumeral offset ratio is a potentially useful preoperative planning tool for total shoulder arthroplasty.     

Effect of reverse total shoulder arthroplasty humeral inclination on glenohumeral range of motion,deltoid force,and glenoid strain: a biomechanical study

BackgroundReverse total shoulder arthroplasty (RSA) primarily varies between 2 implant design options: a 135 humeral stem inclination that closely resembles anatomic orientation, versus the Grammont-style 155 humeral stem inclination that further medializes and distalizes the center of rotation (COR). The purpose of this study was to compare deltoid force, glenoid strain, and simulated glenohumeral range of motion (ROM) between RSA 135 and RSA 155 designs, with a series of standardized permutations of glenosphere offset and rotator cuff pathology.MethodsTwelve fresh-frozen cadaveric shoulder specimens were studied using a shoulder simulator. Native shoulder motion profiles for reproducible abduction range of motion were established using a customized testing device. Optical 3-dimensional tracking and pressure sensors were used to accurately record glenohumeral range of motion (ROM), deltoid force, and glenoid strain for RSA 135 and RSA 155 designs. For each cohort, all combinations of glenosphere offsets and rotator cuff tendon involvement were evaluated.ResultsThere was no significant difference in the overall abduction ROM between the 155 and the 135 humeral stem implants (P = .75). Resting abduction angle and maximum abduction angle were significantly greater with a 155 + STD (standard offset) construct than with a 135 + STD construct (P < .001 and P = .01, respectively). Both stem inclinations decreased combined deltoid force requirements as compared the native shoulder with a massive cuff tear. Effective glenoid strain did not vary significantly between 135 + STD and 155 + STD constructs (P = .66).ConclusionOverall, range of motion between the 135 and the 155 humeral stem inclinations was not significantly different. The cumulative deltoid force was lower in RSA shoulders when compared to native shoulders with massive rotator cuff tears, highlighting the utility of both implant designs. The Grammont-style 155 stem coupled with a 2.5 mm inferior offset glenosphere required less deltoid force to reach maximum abduction than did the more anatomic, lateralized 135 stem coupled with a 4 mm lateral offset glenosphere.Level of EvidenceBasic Science, Biomechanics Controlled Laboratory Study     

Transfer of teres minor with bone pedicle for irreparable posterior–superior rotator cuff tears

BackgroundThe objectives of this study are to evaluate the clinical and radiographic mid- to long-term outcomes of patients treated by teres minor with bone pedicle transfer for irreparable massive rotator cuff tear and to investigate the limitations of this procedure.MethodsClinical outcomes were assessed by quantifying: the range of shoulder motion; a visual analog pain scale; the University of California, Los Angeles Shoulder Score (UCLA score); and the Disability of the Arm, Shoulder, and Hand (DASH) score. Radiographs were assessed for deterioration of the glenohumeral joint and upper migration of the humeral head.ResultsEighteen patients with mean age of 66.9 years and mean follow-up of 74.4 months were included. The technique resulted in significant decrease in shoulder pain. The mean UCLA score improved from 10.3 points initially to 24.1 points at time of final follow-up. However, the postoperative results were classified as poor in 11 shoulders. The mean postoperative DASH score was 27.6 points. The mean active forward elevation significantly improved from 75.9° initially to 121.6° at time of final follow-up. In radiographic assessment, osteoarthritis of the glenohumeral joint progressed in 15 shoulders, and the upper migration of humeral head progressed in 14 shoulders.ConclusionsAggravation of the glenohumeral joint and upper migration of the humeral head both progressed postoperatively at a high rate. Therefore, we conclude that this procedure should no longer be performed despite its relative simplicity.     

Optimal positioning of the humeral component in the reverse shoulder prosthesis

Introduction

Total reverse shoulder arthroplasty is becoming more and more the standard therapeutic practice for glenohumeral arthropathy with massive lesions of the rotator cuff. The biomechanical principle of this prosthesis is represented by the reversion of the normal anatomy of the shoulder joint. This non-anatomical prosthesis leads to a medialization of the rotation centre of the glenohumeral joint and also to a distalization of the humeral head. All that causes a deltoid tension increasing so allowing a larger abduction of the arm. Main complications of the reverse shoulder prosthesis are due to the joint instability, the scapular notching and the wear of the polyethylene insert.

Purpose

The main goal of the present work is to study the effect of the positioning of the humeral component on the intrinsic stability of the reverse shoulder prosthesis. In particular, through finite element method simulations, the variation of the stability ratio of the shoulder joint has been calculated for both vertical and horizontal dislocating loads depending on the humeral stem version angle. Moreover, in order to estimate the wear of the polyethylene cup, some analyses have been developed to calculate the pressures on the polyethylene insert.

Results

The obtained results demonstrate the dislocation of a shoulder prosthesis and the wear of the polyethylene insert can be prevented or limited by conveniently varying the version angle of the humeral component.     

Reverse shoulder arthroplasty for massive irreparable rotator cuff tears: a reliable treatment method

BackgroundMassive irreparable rotator cuff tears (MIRCT) are challenging problems for both patients and surgeons. Reverse total shoulder arthroplasty (RTSA) is a treatment option for patients with MIRCTs. However, previous reports have shown inconsistent results, varying patient satisfaction, and higher complication rates.MethodsThis is a retrospective multi-institutional study (22 institutions, 24 surgeons) of 203 patients (average age, 71 years) who underwent RTSA for MIRCT without glenohumeral arthritis with a mean follow-up of 50 months. Patients were divided into 4 groups based on preoperative shoulder active forward elevation (aFE) (<60°, <90°, ≥90°, >120°). Clinical outcomes were assessed using multiple patient-reported outcome measures (PROs), postoperative range of motion (ROM), patient satisfaction, and complication rate. Radiographic outcomes assessment included evaluation of postoperative scapular notching and humeral radiolucent lines.ResultsPatients in each group had significant (P≤ 0.02) improvements in PROs and ROM postoperatively. Patient satisfaction was highest in the group with >120° preoperative aFE (44/44, 100%). Scapular notching and humeral radiolucency were noted in 6% and 7% of patients, respectively. There were only 3 complications that required 2 revision surgeries. Overall, the complication rate (1.6%) and reoperation rate (1.1%) were considerably lower than previously reported.ConclusionRTSA is a reliable treatment for MIRCTs without glenohumeral arthritis that results in significant improvements in PROs and shoulder ROM. Compared to previous studies, we report a substantially higher satisfaction rates in all patients, especially in those with better preoperative ROM (aFE >120°), and a lower overall complication rate.Level of evidenceLevel IV, retrospective case series.     

Complex Functional Posttraumatic Shoulder Reconstruction Using Shoulder Arthroplasty and a Pedicled Innervated Latissimus Dorsi Flap—A Case Report and Literature Review

Background

The shoulder joint is one of the most freely movable joints in the human body and has therefore high importance for upper limb functionality. Several techniques have been developed to replace the glenohumeral joint including humeral hemiarthroplasty, anatomical total shoulder arthroplasty, and reverse total shoulder arthroplasty, depending on the underlying pathology. For the soft tissue reconstruction, the innervated latissimus dorsi musculocutaneous flap is a reliable solution flap in shoulder and arm reconstruction.

Case presentation

We present the case of a 16-year-old male patient with a complete destruction of the shoulder joint and soft tissues after ballistic trauma. We performed the reconstruction of the shoulder joint using a humeral hemiarthroplasty with a mesh fixation to the remaining glenoid. The soft tissue coverage and the restoration of the deltoid muscle function were insured with a pedicled innervated latissimus dorsi musculocutaneous flap. One year postoperatively, the patient showed a good function of the shoulder joint with an excellent aesthetical result and no pain.

Conclusion

The pedicled latissimus dorsi musculocutaneous flap can safely restore the shoulder function, while the humeral hemiarthroplasty with mesh fixation can be a reliable solution for the reconstruction of a completely destructed shoulder joint.     

Treatment of shoulder sequelae in brachial plexus birth injury

Background Many children with permanent brachial plexus birth injury (BPBI) develop shoulder problems, with subsequent joint deformity without treatment. We assessed the indications and outcome of shoulder operations for BPBI.

Patients and methods 31 BPBI patients who had undergone a shoulder operation in our hospital between March 2002 and December 2005 were included in the study. Relocation of the humeral head had been performed in 13 patients, external rotation osteotomy of the humerus in 5 patients, subscapular tendon lengthening in 5 patients, and teres major transposition in 8 patients. Subjective results were registered. Shoulder range of motion was measured, and function assessed according to the Mallet scale. Magnetic resonance imaging (MRI) was performed pre- and postoperatively. Glenoscapular angle (GSA) and percentage of humeral head anterior to the middle of the glenoid fossa (PHHA) were measured. Congruency of the glenohumeral joint (GHJ) was estimated. The mean follow-up time was 3.8 (1.7–6.8) years.

Results At follow-up, the subjective result was satisfactory in 30 of the 31 patients. There were 4 failures, which in retrospect were due to wrong choice of surgical method in 3 of these 4 patients. Mean increase in Mallet score was 5.5 after successful relocation, 1.4 after rotation osteotomy, 2.2 after subscapular tendon lengthening, and 3.1 after teres major transposition. Congruency of the shoulder joint improved in 10 of 13 patients who had undergone a relocation operation, with mean improvement in GSA of 33º and mean increase in PHHA of 25%. There were no substantial changes in congruency of the glenohumeral joint in patients treated with other operation types.

Interpretation Restriction of the range of motion and malposition of the glenohumeral joint can be improved surgically in brachial plexus birth injury. Remodeling of the joint takes place after successful relocation of the humeral head in young patients.