Clavicular osteotomy in complicated revision of total shoulder arthroplasty: indications, surgical technique, and outcomes.

PURPOSE: Adequate exposure in revision of total shoulder arthroplasty (TSA) is important for optimal prosthesis placement and functional results. A clavicular osteotomy in difficult cases of revision TSA is a useful surgical technique that increases the superior exposure area, provides safer dissection, minimizes damage to the anterior deltoid muscle, improves glenoid access, and allows for superior dislocation of the humeral component. There is a paucity of literature analyzing the clavicular osteotomy during challenging cases of revision TSA. The aims of this study were to describe the application, surgical technique, and outcomes of revision TSA with a clavicular osteotomy. METHODS: This was a retrospective study of consecutive patients who underwent revision TSA with a clavicle osteotomy at a single institution (2004-2016). A curved longitudinal clavicular osteotomy is created parallel to the origin of the anterior deltoid muscle. This allows for lateral reflection of the osteotomy and anterior deltoid muscle to significantly increase superior exposure and reduce damage to remaining deltoid muscle fibres. Osteotomy closure is simple with four or five Nice knot osteosutures. The Constant-Murley score and osteotomy healing were assessed at every follow-up. All complications were reviewed. RESULTS: Forty patients who had a mean age of 63.8 years (range 37-87) at time of surgery and mean follow-up duration of 34 months (range 12-88) were analyzed. Pre-operative Constant-Murley scores improved significantly from 32 ± 19.0 to 58 ± 15.0 (p < 0.001) at one year and 65 ± 13.1 (p < 0.001) at two years. Primary osteotomy healing and callus formation were evident in 95% of cases by three months. Five patients developed post-operative complications (13%) related to the clavicular osteotomy: three mid-diaphyseal clavicular fractures sustained after trauma (8%), one clavicular stress fracture (3%), and case of one loosening (3%). Three patients (8%) required surgical revision of the osteotomy (two internal fixation and one revision osteosuturing). No neurovascular injuries or scapular fractures were encountered. CONCLUSION: A curved longitudinal clavicular osteotomy is beneficial in difficult revision TSA and is another tool in the arsenal of experienced shoulder surgeons who manage these challenging cases. This surgical technique increases glenoid exposure, facilitates superior dislocation of the humeral component, minimizes anterior deltoid damage, and reduces the risk of neurovascular injuries. All clavicular complications occurred within four months prior to osteotomy union, with many sustained due to trauma. However, patients who developed a complication had comparable shoulder function as those without.

Arthroplasty for glenohumeral arthritis in shoulders with a previous Bristow or Latarjet procedure.

BACKGROUND: Coracoid transfer has become increasingly popular for recurrent anterior shoulder instability. Despite the success, glenohumeral arthropathy develops in some patients. Arthroplasty in this population is complicated by altered anatomy, scarring, and retained hardware. This study evaluated shoulder arthroplasty in patients with a previous Latarjet or Bristow procedure. METHODS: Between 1980 and 2014, 33 patients underwent shoulder arthroplasty after coracoid transfer. Of these, 17 men and 13 women were monitored for a minimum of 2 years or until reoperation. Arthroplasty procedures included hemiarthroplasty (HA) in 5, total shoulder arthroplasty (TSA) in 14, and reverse shoulder arthroplasty (RTSA) in 11. Outcome measures included pain, range of motion, complications, and reoperations. RESULTS: At the most recent follow-up, pain had significantly improved in all arthroplasty groups. Elevation and external rotation also improved significantly (P < .001). Overall, 9 shoulders (30%) underwent revision for instability (1 TSA and 1 HA), glenoid loosening (1 TSA), instability and glenoid loosening (3 TSA), late cuff failure (1 TSA), and painful glenoid erosion (2 HA). Revision rates were significantly different between HA and RTSA (P = .0058) and between TSA and RTSA (P = .015). Radiographically, 2 additional anatomic glenoid components were considered loose, progressive medial erosion was seen in 1 HA, and grade 1 to 2 notching was observed in 2 RTSAs. CONCLUSIONS: Shoulder arthroplasty in patients after prior coracoid transfer is technically challenging, yet improvements in pain and function are predictable. Instability and glenoid loosening are common reasons for revision surgery, likely related to difficulties in achieving a good soft tissue balance.

Bony Reconstruction of the Anterior Glenoid Rim.

Recurrent anterior shoulder instability is associated with glenohumeral bone loss. Glenoid deficiency compromises the concavity-compression mechanism. Medial Hill-Sachs lesions can result in an off-track humeral position. Anterior glenoid reconstruction or augmentation prevents recurrence by addressing the pathomechanics. In Bristow and Latarjet procedures, the coracoid process is harvested for conjoint tendon transfer, capsular reinforcement, and glenoid rim restoration. Complications and the nonanatomic nature of the procedure have spurred research on graft sources. The iliac crest is preferred for autogenous structural grafts. Tricortical, bicortical, and J-bone grafts have shown promising results despite the historical association of Eden-Hybinette procedures with early degenerative joint disease. Allogeneic osteochondral grafts may minimize the risk of arthropathy and donor site morbidity. Tibial plafond and glenoid allografts more closely match the native glenoid geometry and restore the articular chondral environment, compared with conventional grafts. Graft availability, cost, risk of disease transmission, and low chondrocyte viability have slowed the acceptance of osteochondral allografts.

Influence of screw type and length on fixation of anterior glenoid bone grafts.

BACKGROUND: Bone-grafting procedures for recurrent shoulder instability produce low recurrence rates, although they are associated with complications such as graft non-union. Inadequate screw purchase is considered to play a causative role. However, excessive screw length can endanger neurovascular structures. The present study aimed to investigate how type and length of screws influences construct rigidity in a simplified glenoid model. METHODS: Testing was performed on composite polyurethane foam models with material properties and abstract dimensions of a deficient glenoid and an bone graft. Three screw types (cannulated 3.75 mm and 3.5 mm and solid 4.5 mm) secured the graft in a bicortical-bicortical, bicortical-unicortical and unicortical-unicortical configuration. Biomechanical testing consisted of applying axial loads when measuring graft displacement. RESULTS: At 200 N, graft displacement reached 0.74 mm, 0.27 mm and 0.24 mm for the unicortical-unicortical and 0.40 mm, 0.25 mm and 0.24 mm for the unicortical-bicortical configuration of the 3.75 mm, 3.5 mm and 4.5 mm screw types. The 3.75 mm screw incurred significant displacements in the unicortical configurations compared to the bicortical-bicortical method (p < 0.001). CONCLUSIONS: The present study demonstrates that common screw types resist physiological shear loads in a bicortical configuration. However, the 3.75 mm screws incurred significant displacements at 200 N in the unicortical configurations. These findings have implications regarding hardware selection for bone-grafting procedures.

Restoration of Articular Geometry Using Current Graft Options for Large Glenoid Bone Defects in Anterior Shoulder Instability.

PURPOSE: The purpose of this cadaveric study was to compare standard and modified coracoid transfer procedures, bicortical and tricortical iliac crest autografts, and tibial plafond and glenoid allografts with respect to glenoid surface curvature restoration. METHODS: Computed tomography scans of 8 cadaveric shoulders were acquired in 9 conditions: (1) intact, (2) 25% width defect, (3) classic Latarjet, (4) modified congruent-arc Latarjet, (5) tricortical iliac crest inner table, (6) outer table, (7) bicortical iliac crest, (8) distal tibia, and (9) glenoid allograft. Outcome measures included articular surface area, width, depth, axial and coronal radius of curvature, and subchondral articular step-off, analyzed in bone and soft-tissue window. RESULTS: Reconstruction of the articular surface area was optimal with the glenoid allograft (99.4%), classic Latarjet (97.4%), and iliac crest bicortical graft (93.2%). Depth was best restored by the congruent-arc Latarjet (101.0%), tibial (98.9%), and glenoid (95.3%) allografts. Axial curvature was closely matched by the glenoid allograft (97.5%), classic Latarjet (108.7%), and iliac bicortical graft (91.2%). Coronal curvature was most accurately restored by the glenoid allograft (102.6%), the tibial allograft (115.0%), and the classic Latarjet (55.9%). The articular step-off was smallest using the glenoid allograft. CONCLUSIONS: Overall, glenoid allografts most accurately restored articular geometry. Alternative grafts provided restoration of some parameters but not others. Classic Latarjet performed well in axial and coronal curvature on average but exhibited large variability. Tibial allograft produced the poorest results in axial curvature, despite excellent coronal curvature reconstruction. The congruent-arc Latarjet did not restore the axial curvature accurately and overcorrected coronal curvature. Graft geometry must be weighed against availability, morbidity, and the role of additional stabilizers. CLINICAL RELEVANCE: Accurate graft morphology may help prevent postoperative osteoarthritis. Grafts differ significantly regarding geometric parameters. The findings of this study will help surgeons select the most appropriate graft for glenoid reconstruction.

Accuracy of the glenohumeral subluxation index in nonpathologic shoulders.

BACKGROUND: Correction of posterior humeral subluxation, measured by the humeral subluxation index (HSI) according to Walch, is necessary in total shoulder arthroplasty to prevent early loosening. The 3-dimensional (3D) measurement of the shoulder is becoming well accepted and common practice as it overcomes positional errors to which 2-dimensional (2D) glenohumeral measurements are prone. The first objective was to describe the HSI in a nonpathologic population with the 2D HSI according to Walch and a newly described 3D HSI method. The second objective was to compare both measuring methods with each other. METHODS: In 151 nonpathologic shoulders, the 2D HSI was measured on the midaxial computed tomography scan cut of the scapula. The 3D HSI, based on the native glenoid plane, was defined as [formula in text], in which X is the projection of the center of the humeral head to the anteroposterior axis of the glenoid fossa and R is the radius of the humeral head. Both measuring methods were compared with each other. Correlation was determined. Interobserver and intraobserver reliability of the 3D HSI was measured. RESULTS: The mean 3D HSI (51.5% ± 2.7%) was significantly (P < .001) more posterior than the mean 2D HSI (48.7% ± 5.2%), with a mean difference of 2.9% ± 5.6%. No correlation was found between the 2D and 3D HSI. The interobserver and intraobserver reliability was excellent. CONCLUSION: The 2D HSI seems to underestimate the humeral subluxation compared with a 3D reliable equivalent.

Iliac bone grafting of the intact glenoid improves shoulder stability with optimal graft positioning.

BACKGROUND: Bone grafting procedures are increasingly popular for the treatment of anterior shoulder instability. In patients with a high risk of recurrence, open coracoid transplantation is preferred but can be technically demanding. Free bone graft glenoid augmentation may be an alternative strategy for high-risk patients without significant glenoid bone loss. This biomechanical cadaveric study assessed the stabilizing effect of free iliac crest bone grafting of the intact glenoid and the importance of sagittal graft position. METHODS: Eight fresh frozen cadaveric shoulders were tested. The bone graft was fixed on the glenoid neck at 3 sagittal positions (50%, 75%, and 100% below the glenoid equator). Displacement and reaction force were monitored with a custom device while translating the humeral head over the glenoid surface in both anterior and anteroinferior direction. RESULTS: Peak force (PF) increased significantly from the standard labral repair to the grafted conditions in both anterior (14.7 ± 5.5 N vs 27.3 ± 6.9 N) and anteroinferior translation (22.0 ± 5.3 N vs 29.3 ± 6.9 N). PF was significantly higher for the grafts at the 50% and 75% positions compared with the grafts 100% below the equator with anterior translation. Anteroinferior translation resulted in significantly higher values for the 100% and 75% positions compared with the 50% position. CONCLUSIONS: This biomechanical study confirms improved anterior glenohumeral stability after iliac crest bone graft augmentation of the anterior glenoid. The results also demonstrate the importance of bone graft position in the sagittal plane, with the ideal position determined by the direction of dislocation.