Stability of novel cow-hitch suture button coracoid bone graft fixation in Latarjet procedures: a biomechanical study.

BACKGROUND: The Latarjet procedure is widely used to address anterior shoulder instability, especially in case of glenoid bone loss. Recently, cortical suture button fixation for coracoid transfer has been used to mitigate complications seen with screw placement. The aim of this biomechanical study was to evaluate the stability of a novel and cost-effective cow-hitch suture button technique, designed to be performed through a standard open deltopectoral approach, and compare this to a well-established double suture button technique. MATERIALS AND METHODS: We randomly assigned 12 fresh frozen cadaveric shoulders to undergo the Latarjet procedure with either 4 suture button (S&N EndoButton) fixations (SB group; n = 6, age 72 ± 9.8 years) or cow-hitch suture button technique using a 1.7-mm FiberTape looped sequentially in 2 suture buttons (Arthrex Pectoralis Button) placed from anterior on the posterior glenoid (CH-SB group; n = 6, age 73 ± 9.3 years). After fixation, all shoulders underwent biomechanical testing with direct loading on the graft via a material testing system. Cyclic loading was performed for 100 cycles (10-100 N) to determine axial displacement with time; each graft was then monotonically loaded to failure. RESULTS: The maximum cyclic displacement was 4.3 ± 1.6 mm for the cow-hitch suture button technique and 5.0 ± 1.7 mm for the standard double suture button technique (P = .46). Ultimate load to failure and stiffness were, respectively, 190 ± 82 N and 221 ± 124 N/mm for the CH-SB technique and 172 ± 48 N and 173 ± 34 N/mm for the standard double SB technique (P = .66 and .43). The most common failure mode was suture cut-through at the anteroinferior aspect of the glenoid for both fixation groups. CONCLUSIONS: The cow-hitch suture button technique resulted in a similar elongation, stiffness, and failure load compared to an established double suture button technique. Therefore, this cost-effective fixation may be an alternative, eligible for open approaches, to the established double suture button techniques.

Clinical and radiographic long-term outcomes of hemiarthroplasty for complex proximal humeral fractures.

BACKGROUND: Hemiarthroplasty (HA) is a treatment option for complex proximal humeral fractures not suitable for conservative treatment or open reduction-internal fixation. Long-term outcomes using a large-metaphyseal volume prosthesis in the management of proximal humeral fractures have not been reported thus far. METHODS: Between 2006 and 2010, 41 patients with proximal humeral fractures were treated with HA at our institution (average age, 62 years; age range, 38-85 years). Nine patients underwent revision surgery, 3 were lost to follow-up, and 7 died unrelated to the index surgical procedure. Twenty-two patients were reviewed clinically and radiographically after a mean period of 10.4 years (range, 9-13 years). RESULTS: Of the 9 HA failures, 7 occurred within the first 2 postoperative years: 2 patients had infections and 5 had greater tuberosity nonunions or malunions. The other 2 patients underwent revision for rotator cuff deficiency >5 years after initial surgery. Among the patients available for final follow-up, the implant survival rate was 71% (22 of 31 patients). At final follow-up, these patients showed a mean relative Constant score of 76% (range, 49%-96%), mean active elevation of 116° (range, 60°-170°), and mean external rotation of 28° (range, 0°-55°). The majority had good or excellent internal rotation, with internal rotation to the 12th thoracic vertebra in 13 patients (59%) and to the eighth thoracic vertebra in 7 (31%). The mean Subjective Shoulder Value was 76% (range, 40%-100%). Clinical outcomes did not significantly deteriorate over a period of 10 years, except for flexion (P < .001) and internal rotation (P = .002). On analysis of greater tuberosity healing, 1 patient had a nonunion and 10 patients (45%) had a malunion, whereas the greater tuberosity had healed in an anatomic position in 12 patients (55%). Patients with a displaced malunion of the greater tuberosity did not have inferior clinical results at last follow-up. Only 2 patients showed glenoid erosion, and in no patients could stem loosening be identified at final follow-up. CONCLUSION: The revision rate following large-metaphyseal volume HA to treat a proximal humeral fracture was 29% after 10 years postoperatively, with failure within 2 years largely related to greater tuberosity nonunion or malunion and failure later related to rotator cuff insufficiency. Patients with a retained implant showed good clinical and radiographic long-term results, without relevant deterioration over time even when the greater tuberosity healed in a nonanatomic position.

Long-term recurrence rate in anterior shoulder instability after Bankart repair based on the on- and off-track concept.

BACKGROUND: Since its first proposal, the concept of on- and off-track lesions in anterior shoulder instability has gained clinical relevance as a tool to predict the failure rate of arthroscopic Bankart repair. Current literature only reports either short-term follow-up or long-term results of small sample sizes. The aim of this study was to provide a long-term evaluation of recurrent instability following arthroscopic Bankart repair in a large cohort using the on-track vs. off-track concept as a predictor for failure. METHODS: We retrospectively analyzed 271 patients who underwent primary arthroscopic Bankart repair for anterior shoulder instability between 1998 and 2007. All patients with a minimum follow-up of 78 months and a preoperative computed tomographic (CT) or magnetic resonance imaging (MRI) scan were included into the study. Preoperative CT and/or MRI scans were used to determine the glenoid track and width of Hill-Sachs lesion. Recurrence of instability was defined as presence of instability symptoms (dislocation, subluxation, and/or apprehension) or revision surgery (stabilization procedure) and was assessed as the primary outcome parameter. RESULTS: The glenoid track of 163 shoulders was assessed (female n = 51, male n = 112) with a mean follow-up of 124 months (99.4-145.6, standard deviation = 2.5) and a mean age of 24 years (20-34.). An off-track Hill-Sachs lesion was found in 77 cases (47%), and in 86 cases (53 %) it was on-track. The rate of recurrent instability in the off-track group was 74% (n = 57) compared with 27% (n = 23) in the on-track group (P < .001). The overall rate of revision surgery due to instability was 29% (n = 48) after a mean time of 50.9 months (±42.8) following Bankart repair. The rate of revision surgery in the off-track group was 48% (n = 37) after a mean of 53.5 months (±42.0) vs. 13% (n = 11) after 42.3 months (±46.3) in the on-track group (P < .001). CONCLUSION: This study shows that the on- and off-track concept helps to distinguish patients for whom an isolated arthroscopic Bankart repair yields long-term benefits. Because of the high rate of recurrent instability in the off-track group, an off-track lesion should be treated surgically in such a way that the off-track lesion is converted into an on-track lesion.

Why is female gender associated with poorer clinical outcomes after reverse total shoulder arthroplasty?

INTRODUCTION: There is a lack of gender-specific research after reverse total shoulder arthroplasty (RTSA). Although previous studies have documented worse outcomes in women, a more thorough understanding of why outcomes may differ is needed. We therefore asked: (1) Are there gender-specific differences in preoperative and postoperative clinical scores, complications, surgery-related parameters, and demographics? (2) Is female gender an independent risk factor for poorer clinical outcomes after RTSA? (3) If so, why is female gender associated with poorer outcomes after RTSA? MATERIALS AND METHODS: Between 2005 and 2019, 987 primary RTSAs were performed in our institution. After exclusion criteria were applied, data of 422 female and 271 male patients were analyzed. Clinical outcomes (absolute/relative Constant Score [a/rCS] and Subjective Shoulder Value [SSV]), complications (intra- and/or postoperative fracture, loosening), surgery-related parameters (indication, implant-related characteristics), and demographics (age, gender, body mass index, and number of previous surgeries) were evaluated. Preoperative and postoperative radiographs were analyzed (critical shoulder angle, deltoid-tuberosity index, reverse shoulder angle, lateralization shoulder angle, and distalization shoulder angle). RESULTS: Preoperative clinical scores (aCS, rCS, SSV, and pain level) and postoperative clinical outcomes (aCS and rCS) were significantly worse in women. However, the improvement between preoperative and postoperative outcomes was significantly higher in female patients for rCS (P = .037), internal rotation (P < .001), and regarding pain (P < .001). Female patients had a significantly higher number of intraoperative and postoperative fractures (24.9% vs. 11.4%, P < .001). The proportion of female patients with a deltoid-tuberosity index <1.4 was significantly higher than males (P = .01). Female gender was an independent negative predictor for postoperative rCS (P = .047, coefficient -0.084) and pain (P = .017, coefficient -0.574). In addition to female sex per se being a predictive factor of worse outcomes, females were significantly more likely to meet 2 of the 3 most significant predictive factors: (1) significantly worse preoperative clinical scores and (2) higher rate of intra- and/or postoperative fractures. CONCLUSIONS: Female sex is a very weak, but isolated, negative predictive factor that negatively affects the objective clinical outcome (rCS) after RTSA. However, differences did not reach the minimal clinically important difference, and it is not a predictor for the subjective outcome (SSV). The main reason for the worse outcome in female patients seems to be a combination of higher preoperative disability and higher incidence of fractures. To improve the outcome of women, all measures that contribute to the reduction of perioperative fracture risk should be used.

Inadvertent, intraoperative, non- to minimally displaced periprosthetic humeral shaft fractures in RTSA do not affect the clinical and radiographic short-term outcome.

INTRODUCTION: Little information is available on the clinical and radiographic outcome of intraoperative, non- to minimally displaced humeral fractures that occur during implantation of a stemmed, reverse shoulder prosthesis but are only recognized on routine postoperative radiographs. The goal of this study is to report the clinical and radiographic outcome for this rarely reported fracture type. MATERIALS AND METHODS: 39 conservatively treated non- to minimally displaced intraoperative periprosthetic humeral fractures after stemmed RTSA were detected from our radiographic database between 1.1.2006 and 31.1.2018. Exclusion criteria were lack of patient consent, preoperative humeral fracture, and revision arthroplasties. Clinical (absolute and relative Constant score, the Subjective Shoulder Value) and radiographic (conventional radiographs) assessment was performed preoperatively, at 6 weeks (only radiographically) and at latest follow-up with a minimum follow-up of 2 years. RESULTS: 35 patient's with a mean age of 72 years (range 32-88, SD ± 11 years) and a mean follow-up of 53 months (range 24-124, SD ± 31) were included in the study. At latest follow-up, all clinical outcome parameters except external rotation improved significantly. A complication rate of 17% (n:6) was recorded. At 6 weeks after the index surgery, none of the radiographs showed a fracture displacement or a sintering of the stem. At latest follow-up, all fractures were healed and no stem loosening was observed in any of the shoulders. CONCLUSIONS: Non- to minimally displaced intraoperative periprosthetic humeral fractures in RTSA have an incidence of about 5% in this series of mainly uncemented press-fit stems. They generally heal without any further treatment and are not associated with stem loosening or compromise the clinical outcome after primary RTSA. Except slight restriction in the postoperative rehabilitation protocol, no further attention or action is needed.

Augmented reality through head-mounted display for navigation of baseplate component placement in reverse total shoulder arthroplasty: a cadaveric study.

BACKGROUND: To achieve an optimal clinical outcome in reverse total shoulder arthroplasty (RSA), accurate placement of the components is essential. The recently introduced navigation technology of augmented reality (AR) through head-mounted displays (HMD) offers a promising new approach to visualize the anatomy and navigate component positioning in various orthopedic surgeries. We hypothesized that AR through HMD is feasible, reliable, and accurate for guidewire placement in RSA baseplate positioning. METHODS: Twelve human cadaver shoulders were scanned with computed tomography (CT) and RSA baseplate positioning was 3-D planned using dedicated software. The shoulders were prepared through a deltopectoral approach and an augmented reality hologram was superimposed using the HMD Microsoft HoloLense. The central guidewire was then navigated through the HMD to achieve the planned entry point and trajectory. Postoperatively, the shoulders were CT-scanned a second time and the deviation from the planning was calculated. RESULTS: The mean deviation of the entry point was 3.5 mm ± 1.7 mm (95% CI 2.4 mm; 4.6 mm). The mean deviation of the planned trajectory was 3.8° ± 1.7° (95% CI 2.6°; 4.9°). CONCLUSION: Augmented reality seems feasible and reliable for baseplate guidewire positioning in reverse total shoulder arthroplasty. The achieved values were accurate.

Reversed total shoulder arthroplasty after acromioclavicular joint resection yields equivalent clinical results compared to a matched control group.

INTRODUCTION: Reverse total shoulder arthroplasty (RTSA) is a well-establish procedure with increasing incidence. Depending on the medical history, many patients undergo multiple soft-tissue procedures before RTSA. The role of acromioclavicular pathology as well as the consequences of a distal clavicle resection (DCR) before RTSA has not been evaluated yet. MATERIAL AND METHODS: A retrospective single-center review was performed on all patients undergoing primary RTSA with or without DCR with a minimum follow-up of 2 years. We compared patient-reported outcome measures (Constant score (CS), subjective shoulder values (SSV), and range of motion (ROM)) with a matched control group. The control group consisted of patients treated with a RTSA without DCR and matching was performed for age, sex, operating side, American Society of Anesthesiologists (ASA), body mass index (BMI), and indication. Surgical time and complication rate were recorded. RESULTS: Thirty-nine patients with a mean follow-up of 63 months (SD 33) were enrolled in the study group. Mean age was 67 years (SD 7) with 44% male patients for both groups. The mean relative CS improved from 43% (SD 17) to 73% (SD 20) in the study group, and from 43% (18) to 73% (22) in the control group. The SSV improved from 29% (SD 17) to 63% (SD 29) in the study group, and from 28% (SD 16) to 69% (SD 26) in the control group (both n.s.). The postoperative ROM did not significantly differ between the two groups. Five patients in the study group and six in the control group had reoperations. CONCLUSION: Patients who received a DCR before RTSA showed equivalent clinical outcomes compared to a match-control group with RTSA only. Surgical time was not different, and no complication related to the open DCR was observed in the study group. Therefore, we conclude that a prior DCR does not influence the postoperative outcome after RTSA. LEVEL OF EVIDENCE: Level III: Retrospective comparative study.

Dual energy CT arthrography in shoulder instability: successful iodine removal with virtual non-contrast images and accurate 3D reformats of the glenoid for assessment of bone loss.

OBJECTIVE: To evaluate the image quality of dual energy CT (DECT) of the shoulder after arthrography and of virtual non-contrast (VNC) 3D reformats of the glenoid and to compare glenoid measurements on VNC 3D reformats and on 2D CTs. MATERIALS AND METHODS: DECT arthrography (80 kV/140 kV) was performed in 42 shoulders of 41 patients with instability using diluted iodinated contrast media (80 mg/ml). VNC images and VNC 3D reformats of the glenoid were calculated using image postprocessing. Dose parameters, CT values of intraarticular iodine and muscle, image contrast (iodine/muscle), and image quality (5-point scale: 1 = worst, 5 = best) were evaluated. Two independent readers assessed glenoid morphology and performed glenoid measurements on 2D and 3D images. RESULTS: Calculation of VNC images and VNC 3D reformats was successful in 42/42 shoulders (100%). The effective dose was mean 1.95 mSv (± 0.9 mSv). CT values of iodine and muscle were mean 1014.6 HU (± 235.8 HU) and 64.5 HU(± 8.6 HU), respectively, and image contrast was mean 950.2 HU (± 235.5 HU). Quality of cross-sectional images, VNC images, and VNC 3D reformats was rated good (median 4 (4-5), 4 (3-4), 4 (3-5), respectively). Detection of an osseous defect was equal on 2D and 3D images (13/42, P > 0.99) with no difference for measurement of the glenoid diameter with mean 28.3 mm (± 2.8 mm) vs. 28.4 mm (± 2.9 mm) (P = 0.5), width of the glenoid defect with 3.2 mm (± 2.1 mm) vs. 3.1 mm (± 2.3 mm) (P = 0.84), surface area with 638.5 mm2 (± 127 mm2) vs. 640.8 mm2 (± 129.5 mm2) (P = 0.47), and surface area of the defect with 46.6 mm2 (± 44.3 mm2) vs. 47.2 mm2 (± 48.0 mm2) (P = 0.73), respectively. CONCLUSION: DECT shoulder arthrography is feasible and allows successful iodine removal with generation of VNC images and accurate VNC 3D reformats of the glenoid for assessment of bone loss.

Virtual non-contrast images calculated from dual-energy CT shoulder arthrography improve the detection of intraarticular loose bodies.

OBJECTIVE: This study aims to evaluate the image quality of virtual non-contrast (VNC) images calculated from dual-energy CT shoulder arthrography (DECT-A) and their ability to detect periosteal calcifications and intraarticular loose bodies. MATERIALS AND METHODS: In 129 shoulders of 123 patients, DECT arthrography (80 kV/140 kV) was performed with diluted iodinated contrast material (80 mg/ml). VNC images were calculated with image postprocessing. VNC image quality (1 = worst, 5 = best), dose parameters, and CT numbers (intraarticular iodine, muscle, VNC joint fluid density) were assessed. Image contrast (iodine/muscle) and percentage of iodine removal were calculated. Two independent readers evaluated VNC and DECT-A images for periosteal calcifications and intraarticular loose bodies, and diagnostic confidence (1 = low, 4 = very high) was assessed. RESULTS: VNC images (129/129) were of good quality (median 4 (3-4)), and the mean effective dose of DECT-A scans was 2.21 mSv (± 1.0 mSv). CT numbers of iodine, muscle, and VNC joint fluid density were mean 1017.6 HU (± 251.6 HU), 64.6 HU (± 8.2 HU), and 85.3 HU (± 39.5 HU), respectively. Image contrast was mean 953.1 HU (± 251 HU) on DECT-A and 31.3 HU (± 32.3 HU) on VNC images. Iodine removal on VNC images was 91% on average. No difference was observed in the detection of periosteal calcifications between VNC (n = 25) and DECT-A images (n = 21) (p = 0.29), while the detection of intraarticular loose bodies was superior on VNC images (14 vs. 7; p = 0.02). Diagnostic confidence was higher on VNC images for both periosteal calcifications (median 3 (3-3) vs. 3 (3-3); p = 0.009) and intraarticular loose bodies (median 3 (3-4) vs. 3 (3-3); p < 0.001). CONCLUSION: VNC images from DECT shoulder arthrography are superior to DECT-A images for the detection of intraarticular loose bodies and increase the confidence in detecting periosteal calcifications.

Arthroscopic single anchor repair techniques for upper third subscapularis tears provide sufficient biomechanical stability.

PURPOSE: Upper third tears of the subscapularis tendon can be repaired successfully with a single anchor according to previous literature. The aim of the present study was to compare three single anchor repair techniques regarding fixation strength, footprint coverage and contact pressure in a biomechanical test set-up on human cadaveric shoulders. METHODS: Eighteen human cadaveric shoulders were randomized in three groups with respect to the repair technique; group 1: knotted lasso-loop mattress, group 2: knotted mattress and group 3: knotless tape repair. Upper third tears of the subscapularis tendon (Lafosse type 2) were created and repairs were performed with additional contact pressure and area measurement using a pressure mapping system. Cyclic testing was performed by loading the subscapularis from 10 to 100 N for 300 cycles. A position-controlled ramp protocol up to 30 and 50 N was used to allow for pressure measurements. Finally, specimens were loaded to failure and failure modes were recorded. RESULTS: The three groups were not significantly different regarding age, gender, bone mineral density at the lesser tuberosity, subscapularis footprint size and defect area created at the upper subscapularis insertion. A significant difference was detected between group 1 (48.6 ± 13.8%) and group 2 (25.9 ± 5.7%) regarding pressurized footprint coverage (p = 0.028). Ultimate load to failure was 630.8 ± 145.3 N in group 1, 586.9 ± 220.7 N in group 2 and 678.2 ± 236.5 N in group 3, respectively. Cyclic displacement was similar in all three groups with an average displacement of 1.2 ± 0.6 mm. The highest stiffness was found in group 1 with 88 ± 30.3, which was not statistically significantly different to group 2 (65 ± 27 N/mm) and group 3 (83.9 ± 32.9 N/mm). The most common mode of failure was suture cut-through at the suture-tendon interface (44%). Failures in group 3 were less common associated with suture cut-through (33% vs. 50% in group 1 and 2), but no significant differences were found. CONCLUSIONS: All three tested single anchor repair techniques of upper third subscapularis tears were able to provide sufficient biomechanical stability. Knotted lasso-loop mattress and knotless tape repair were superior regarding pressurized footprint coverage compared to a knotted horizontal mattress technique and are, therefore, preferable techniques for upper subscapularis repair.

Incidence, radiographic predictors, and clinical outcome of acromial stress reaction and acromial fractures in reverse total shoulder arthroplasty.

BACKGROUND: Acromial and scapular spine fractures (ASFs) are known complications following implantation of reverse total shoulder arthroplasty (RTSA). The entity of acromial stress reaction (ASR) without fracture has recently been described. The purpose of this study was to analyze the incidence, radiographic predictors, treatment options, healing rates, and clinical outcomes of ASF and ASR compared with a control group. METHODS: A total of 854 primary RTSAs were implanted between 2005 and 2018 in a single shoulder unit of a tertiary referral hospital and retrospectively reviewed for the incidence of ASF and ASR. ASR was defined as pain at the acromion or scapular spine after fracture exclusion on computed tomography scans. The ASF group was matched to a control group. Preoperative and postoperative radiographs were analyzed for radiographic predictors of ASF or ASR. The impact of ASF and ASR, operative vs. nonoperative treatment, and fracture union on clinical outcomes (Constant-Murley score [CS], Subjective Shoulder Value [SSV], and range of motion) with a minimum follow-up period of 2 years was analyzed. RESULTS: A total of 46 ASFs (5.4%) in 44 patients and 44 ASRs (5.2%) in 43 patients were detected at a mean of 16 ± 24 months and 20 ± 23 months postoperatively, respectively. Predictive radiographic factors were an increased critical shoulder angle and lateralization shoulder angle. The overall union rate was 55% (22 of 40) but was significantly higher following operative treatment (9 of 11, 82%) compared with nonoperative treatment (13 of 29, 45%). Patients with ASF or ASR demonstrated inferior clinical outcomes (CS, 44 ± 21 and 48 ± 18; SSV, 52% ± 25% and 57% ± 27%) compared with the control group (CS, 66 ± 14; SSV, 82% ± 22%) independent of bony union or treatment at a mean of 59 ± 33 months (ASF) and 61 ± 38 months (ASR). CONCLUSION: ASF and ASR are frequent complications following RTSA implantation with similar poor clinical outcome measures. The healing rate was shown to be much higher with a surgical approach. Nevertheless, fracture consolidation does not result in better clinical outcomes compared with nonunion.

Acne cream reduces the deep Cutibacterium acnes tissue load before elective open shoulder surgery: a randomized controlled pilot trial.

BACKGROUND: Cutibacterium acnes is the main pathogen in periprosthetic shoulder infections. In acne vulgaris therapy, benzoyl peroxide-miconazole nitrate cream effectively reduces the superficial C acnes burden of the skin. Its additional potential in the subcutaneous and capsular layers (eg, for prevention of future periprosthetic shoulder infections) is unknown. The aim of this study was to investigate the efficacy of a topical acne vulgaris cream (benzoyl peroxide-miconazole nitrate) to reduce subcutaneous and capsular C acnes in individuals with C acnes skin colonization undergoing open shoulder surgery. METHODS: A prospective randomized pilot trial was performed, allocating 60 adult patients (1:1) to either a 7-day preoperative application of a commercial acne cream (benzoyl peroxide-miconazole nitrate) on the preoperative skin (intervention group) or no cream (control group) from November 1, 2018, to May 31, 2020. The superficial skin of the shoulder was sampled at enrollment and before incision, and deep subcutaneous and capsular shoulder samples were taken during surgery. RESULTS: Sixty patients (mean age, 59 years; 55% female patients) undergoing primary open shoulder surgery (17 Latarjet procedures and 43 arthroplasties) were included in the study. At baseline, both randomized groups showed the presence of C acnes on the skin at a rate of 60% (18 of 30 patients in intervention group and 19 of 30 patients in control group, P = .79). In patients with C acnes skin colonization, the intervention resulted in a significant reduction in the overall number of intraoperative samples with positive findings compared with the control group (8 of 18 patients vs. 16 of 19 patients, P = .01), especially in capsular samples (0 of 18 patients vs. 4 of 19 patients, P = .04). CONCLUSION: The topical 7-day preoperative skin application of acne cream (benzoyl peroxide-miconazole nitrate) significantly reduced the intraoperative C acnes load in 56% of the patients in the intervention group compared with 16% of the control patients.

Long-term results after posterior open glenoid wedge osteotomy for posterior shoulder instability associated with excessive glenoid retroversion.

BACKGROUND: Treatment of posterior shoulder instability (PSI) associated with excessive glenoid retroversion is a rare, challenging problem in shoulder surgery. One proposed technique is posterior open wedge glenoid osteotomy to correct excessive glenoid retroversion as described by Scott. However, this operation is rarely performed, and limited long-term outcomes using this approach are available. The goal of this study was to analyze the long-term outcomes of posterior open wedge glenoid osteotomy for PSI associated with excessive glenoid retroversion. METHODS: Six consecutive patients (7 shoulders) with a mean age of 24 years (range 19-34) were treated with posterior open wedge glenoid osteotomy for PSI associated with a glenoid retroversion greater than 15° and followed up clinically and radiographically at a mean age of 15 years (range 10-19). RESULTS: Recurrent, symptomatic PSI was observed in 6 of 7 shoulders (86%). One necessitated revision with a posterior (iliac crest) bone block procedure and was rated as a failure and excluded from functional analysis. One patient rated his result as excellent, 3 as good, 1 as fair, and 1 as unsatisfactory. Mean relative Constant Score (CS%) was unchanged from preoperation to final follow-up (CS% = 72%) and pain did not significantly decrease (Constant Score = 7-10 points; P = .969). The mean Subjective Shoulder Value (SSV) improved postoperatively, but with 6 patients the improvement did not reach statistical significance (SSV = 42%-67%, P = .053) and the total Western Ontario Shoulder Instability Index averaged 30% at the final follow-up. Mean glenoid retroversion of all 7 shoulders was corrected from 20° (range 16°-26°) to 3° (range -3° to +8°) (P = .018). In the 5 shoulders with preoperative static posterior subluxation of the humeral head, the humeral head was not recentered. All 7 shoulders showed progression of glenoid arthritic changes. CONCLUSIONS: Posterior open wedge glenoid osteotomy for PSI associated with excessive glenoid retroversion neither reliably restored shoulder stability nor recentered the joint or prevent progression of osteoarthritis. Alternative treatments for PSI associated with excessive glenoid retroversion have to be developed and evaluated.

Reverse shoulder arthroplasty after failed tendon transfer for irreparable posterosuperior rotator cuff tears.

BACKGROUND: Tendon transfers (TTs) can be successful for the management of selected posterosuperior functionally irreparable rotator cuff tears. However, when these procedures fail to provide adequate pain relief or functional improvement, reverse shoulder arthroplasty (RSA) is commonly considered the next treatment option. The effect of prior TT on RSA remains largely unknown. The purposes of this investigation were to evaluate the outcomes of RSA after previous TT performed for posterosuperior functionally irreparable rotator cuff tears and to determine the effect of various TT types on RSA. METHODS: A retrospective review of 2 institutional databases identified 33 patients who underwent RSA implantation between 2006 and 2019 with a previous failed tendon transfer (FTT) of the shoulder and at least 2 years of clinical follow-up. FTTs included 21 latissimus dorsi transfers, 6 latissimus dorsi and teres major (LD-TM) transfers, and 6 lower trapezius transfers. RSAs were performed at an average of 5.5 years (range, 0.3-28 years) after FTT, with a mean follow-up period of 4.1 ± 2.0 years. Outcomes evaluated included the visual analog scale pain score, range of motion, absolute Constant-Murley score (CS) and relative CS, American Shoulder and Elbow Surgeons score, Subjective Shoulder Value, complications, and implant survivorship free of reoperation or revision. RESULTS: RSA significantly improved pain and function, with improvements in the visual analog scale pain score (6.2 preoperatively vs. 2.2 at most recent follow-up, P < .001), active elevation (85° vs. 111°, P < .001), American Shoulder and Elbow Surgeons score (51 vs. 74, P = .001), absolute CS (34 vs. 48, P = .003), and relative CS (42% vs. 59%, P = .002), exceeding the minimal clinically important difference threshold. There were 7 complications (21%) across the entire cohort, with dislocation (n = 3, 9.1%) as the most common complication. Comparison across TT groups showed that LD-TM transfer had the highest complication rate (3 shoulders, 50%), followed by lower trapezius transfer (1 shoulder, 16.7%); latissimus dorsi transfer had the lowest rate (3 shoulders, 14.3%; P = .037). Survivorship free of revision or reoperation was estimated to be 90.1% at 1 year, 84.9% at 2 years, and 71.2% at 5 years, with no difference among TT groups (P = .654). CONCLUSIONS: RSA can serve as a viable salvage option for FTT procedures. At mid-term follow-up, RSA led to significant improvements in pain, range of motion, and patient-reported outcomes. Patients with prior LD-TM transfers may have a higher complication rate, but no other differences were found between TT groups.

Reverse total shoulder arthroplasty in patients with type B2, B3, and type C glenoids: comparable clinical outcome to patients without compromised glenoid bone stock-a matched pair analysis.

BACKGROUND: Primarily posterior bone deficient (dysplastic) (Walch type C) or secondarily eroded (Walch type B2 or B3) glenoids represent a surgical challenge for shoulder arthroplasty. Due to the posteriorly static decentered head, reverse total shoulder arthroplasty (RTSA) is often considered as the treatment of choice. The purpose of this study is to report the clinical and radiographic outcomes, complications and reoperations of RTSA for posteriorly deficient glenoids. MATERIALS AND METHODS: All patients who underwent RTSA for osteoarthritis secondary to underlying glenoid deficiency (Walch type B2, B3 and C) between 2005 and 2018 (study group), were identified from our institutional shoulder arthroplasty database and gender- and age-matched to a cohort of patients with normal glenoid bone stock (control group). Longitudinal pre- and postoperative clinical [Constant-Murley (CS) score, Subjective Shoulder Value (SSV)] and radiographic outcomes were assessed. RESULTS: We included 188 patients (94 in each group). The median follow-up was 43 ± 26 (24-144) months in the study group and 59 ± 32 (24-124) months in the control group. The glenoid deficiency was addressed by using glenoid bone reconstruction. The surgical site complication and revision rate of RTSA in patients with bony deficient glenoids were 17% and 7%. Although glenoid loosening was slightly higher in the study group (5 vs. 2), overall no significant differences were found between the study and control groups in satisfaction scores, preoperative and postoperative absolute and relative Constant scores, complication and revision rates, respectively. CONCLUSION: Reverse total shoulder arthroplasty (RTSA) seems to be a valuable treatment option for patients with primary (dysplasia) or secondary (wear) posterior glenoid deficiency. Although severe glenoid bone loss seems to be a risk factor for glenoid component failure, the overall complication and revision rates as well as clinical and radiographic outcome are comparable to RTSA in patients without compromised glenoid bone stock. LEVEL OF EVIDENCE: Level III: case-control study.

Acromioclavicular joint stabilization with a double cow-hitch technique compared to a double tight-rope: a biomechanical study.

INTRODUCTION: The aim of the present biomechanical study was to evaluate the stability of a novel simple and cost-effective mini-open double cow-hitch suture button technique of acromioclavicular (AC) joint stabilization in comparison to a well-established double tight-rope technique. MATERIALS AND METHODS: A total of 12 fresh-frozen cadaveric shoulders were randomized into two treatment groups. In either a coracoclavicular stabilization with a standard double tight-rope technique (Group 1; n = 6, age 78 years ± 10) or a double cow-hitch with two No. 5 FiberWire strains looped in a bicortical button placed at the bottom of the coracoid process (Group 2; n = 6, age 80 years ± 13). Both techniques were equally augmented with an AC joint cerclage using a FiberTape. All shoulders were tested in a servo-hydraulic material testing machine for elongation/cyclic displacement (in mm) after cyclic loading (70 N cyclical load, 1500 cycles), stiffness (N/mm) and ultimate load to failure (N). The mechanism of failure was recorded. All tests were performed in a previously published testing setup. RESULTS: After 1500 cycles, group 2 showed a cyclic displacement of 1.67 mm (SD 0.85), compared to 1.04 mm (SD 0.23) cyclic displacement in group 1 (p = 0.11). The cyclic displacement after AC reconstruction in group 1 was 0.36 mm lower than in the native state with intact ligaments (p = 0.19), whereas the cyclic elongation in group 2 was 0.05 mm higher compared to the native situation (p = 0.87). Stiffness after reconstruction was significantly higher in group 1 compared to the native specimen (p = 0.001), in group 2 it was similar as before the reconstruction (p = 0.64). Ultimate load to failure and stiffness were higher in group 1 with 424 N (SD 237) and 68.6 N/mm (SD 8.2), compared to 377 N (SD 152) and 68 N/mm (SD 13.3) in group 2, without reaching statistical significance (p = 0.69 and 0.89). The most common failure modes were clavicular fractures at the tight rope drill holes (n = 2) and clavicular fractures medially at the fixation site (n = 2) in group 1, and coracoid button break-through (n = 3) and clavicular fractures medially at the fixation site (n = 2) in group 2. CONCLUSIONS: Stabilization of the AC joint with a novel mini-open double cow-hitch suture button technique resulted in a similar low elongation, high stiffness and ultimate load to failure compared to a double tight-rope technique. This cost-effective technique for AC joint stabilization could demonstrate a sufficient biomechanical stability with especially high stiffness and load-to-failure. LEVEL OF EVIDENCE: Biomechanical study.

Biomechanical stability of complex coronal plane fracture fixation of the capitellum.

INTRODUCTION: Coronal plane fractures of the distal humerus are relatively rare and can be challenging to treat due to their complexity and intra-articular nature. There is no gold standard for surgical management of these complex fractures. The purpose of this study was to compare the biomechanical stability and strength of two different internal fixation techniques for complex coronal plane fractures of the capitellum with posterior comminution. MATERIALS AND METHODS: Fourteen fresh frozen, age- and gender-matched cadaveric elbows were 3D-navigated osteotomized simulating a Dubberley type IIB fracture. Specimens were randomized into one of two treatment groups and stabilized with an anterior antiglide plate with additional anteroposterior cannulated headless compression screws (group antiGP + HCS) or a posterolateral distal humerus locking plate with lateral extension (group PLP). Cyclic testing was performed with 75 N over 2000 cycles and ultimately until construct failure. Data were analyzed for displacement, construct stiffness, and ultimate load to failure. RESULTS: There was no significant difference in displacement during 2000 cycles (p = 0.291), stiffness (310 vs. 347 N/mm; p = 0.612) or ultimate load to failure (649 ± 351 vs. 887 ± 187 N; p = 0.140) between the two groups. CONCLUSIONS: Posterolateral distal humerus locking plate achieves equal biomechanical fixation strength as an anterior antiglide plate with additional anteroposterior cannulated headless compression screws for fracture fixation of complex coronal plane fractures of the capitellum. These results support the use of a posterolateral distal humerus locking plate considering the clinical advantages of less invasive surgery and extraarticular metalware. LEVEL OF EVIDENCE: Biomechanical study.

Down-Regulation of Mitochondrial Metabolism after Tendon Release Primes Lipid Accumulation in Rotator Cuff Muscle.

Atrophy and fat accumulation are debilitating aspects of muscle diseases and are rarely prevented. Using a vertical approach combining anatomic techniques with omics methodology in a tenotomy-induced sheep model of rotator cuff disease, we tested whether mitochondrial dysfunction is implicated in muscle wasting and perturbed lipid metabolism, speculating that both can be prevented by the stimulation of ß-oxidation with l-carnitine. The infraspinatus muscle lost 22% of its volume over the first 6 weeks after tenotomy before the area-percentage of lipid increased from 8% to 18% at week 16. Atrophy was associated with the down-regulation of mitochondrial transcripts and protein and a slow-to-fast shift in muscle composition. Correspondingly, amino acid levels were increased 2 weeks after tendon release, when the levels of high-energy phosphates and glycerophospholipids were lowered. l-Carnitine administration (0.9 g/kg per day) prevented atrophy over the first 2 weeks, and mitigated alterations of glutamate, glycerophospholipids, and carnitine levels in released muscle, but did not prevent the level decrease in high-energy phosphates or protein constituents of mitochondrial respiration, promoting the accumulation of longer lipids with an increasing saturation. We conclude that the early phase of infraspinatus muscle degeneration after tendon release involves the elimination of oxidative characteristics associated with an aberrant accumulation of lipid species but is largely unrelated to the prevention of atrophy with oral l-carnitine administration.

Posterior Open-wedge Osteotomy and Glenoid Concavity Reconstruction Using an Implant-free, J-shaped Iliac Crest Bone Graft in Atraumatic Posterior Instability with Pathologic Glenoid Retroversion and Dysplasia: A Preliminary Report.

BACKGROUND: Atraumatic posterior shoulder instability in patients with pathologic glenoid retroversion and dysplasia is an unsolved problem in shoulder surgery. QUESTIONS/PURPOSES: In a preliminary study of a small group of patients with atraumatic posterior shoulder instability associated with glenoid retroversion ≥ 15° and glenoid dysplasia who underwent posterior open-wedge osteotomy and glenoid concavity reconstruction using an implant-free, J-shaped iliac crest bone graft, we asked: (1) What proportion of the patients had persistent apprehension? (2) What were the improvements in patient-reported shoulder scores? (3) What were the radiographic findings at short-term follow-up? METHODS: Between 2016 and 2018, we treated seven patients for atraumatic posterior shoulder instability. We performed this intervention when posterior shoulder instability symptoms were unresponsive to physiotherapy for at least 6 months and when it was associated with glenoid retroversion ≥ 15° and dysplasia of the posteroinferior glenoid. All seven patients had a follow-up examination at a minimum of 2 years. The median (range) age at surgery was 27 years (16 to 45) and the median follow-up was 2.3 years (2 to 3). Apprehension was assessed by a positive posterior apprehension and/or posterior jerk test. Patient-reported shoulder scores were obtained and included the subjective shoulder value, obtained by chart review (and scored with 100% representing a normal shoulder; minimum clinically important difference [MCID] 12%), and the Constant pain scale score (with 15 points representing no pain; MCID 1.5 points). Radiographic measurements included glenohumeral arthropathy and posterior humeral head subluxation, bone graft union, correction of glenoid retroversion and glenoid concavity depth, as well as augmentation of glenoid surface area. All endpoints were assessed by individuals not involved in patient care. RESULTS: In four of seven patients, posterior apprehension was positive, but none reported resubluxation. The preoperative subjective shoulder value (median [range] 40% [30% to 80%]) and Constant pain scale score (median 7 points [3 to 13]) were improved at latest follow-up (median subjective shoulder value 90% [70% to 100%]; p = 0.02; median Constant pain scale score 15 points [10 to 15]; p = 0.03). Posterior glenoid cartilage erosion was present in four patients (all four had Walch Type B1 glenoids) preoperatively and showed no progression until the final follow-up examination. The median (range) humeral head subluxation index decreased from 69% (54% to 85%) preoperatively to 55% (46% to 67%) postoperatively (p = 0.02), and in two of four patients with preoperative humeral head subluxation (> 65% subluxation), it was reversed to a centered humeral head. CT images showed union in all implant-free, J-shaped iliac crest bone grafts. The median preoperative retroversion was corrected from 16° (15° to 25°) to 0° postoperatively (-5° to 6°; p = 0.02), the median glenoid concavity depth was reconstructed from 0.3 mm (-0.7 to 1.6) preoperatively to 1.2 mm (1.1 to 3.1) postoperatively (p = 0.02), and the median preoperative glenoid surface area was increased by 20% (p = 0.02). No intraoperative or postoperative complications were recorded, and no reoperation was performed or is planned. CONCLUSION: In this small, retrospective series of patients treated by experienced shoulder surgeons, a posterior J-bone graft procedure was able to reconstruct posterior glenoid morphology, correct glenoid retroversion, and improve posterior shoulder instability associated with pathologic glenoid retroversion and dysplasia, although four of seven patients had persistent posterior apprehension. Although no patients in this small series experienced complications, the size and complexity of this procedure make it likely that as more patients have it, some will develop complications; future studies will need to characterize the frequency and severity of those complications, and we recommend that this procedure be done only by experienced shoulder surgeons. The early results in these seven patients justify further study of this procedure for the proposed indication, but longer term follow-up is necessary to continue to assess whether it is advantageous to combine the reconstruction of posterior glenoid concavity with correction of pathological glenoid retroversion and increasing glenoid surface compared with traditional surgical techniques such as the posterior opening wedge osteotomy or simple posterior bone block procedures. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Anatomical study of the teres major muscle: description of an additional distal muscle slip.

BACKGROUND: Understanding muscle and tendon anatomy is of tremendous importance to achieve optimal surgical execution and results in tendon transfers around the shoulder. The aim of this study was to introduce and describe an additional distal muscle slip of the teres major (TM). METHODS: Sixteen fresh-frozen cadaver shoulders were dissected with the deltopectoral approach. The ventral latissimus dorsi (LD) tendon was harvested, and the shoulders were analyzed for the presence/absence of a distal teres major slip (dTMs) and its dimensions and relationship with the TM and LD tendons. RESULTS: The dTMs was identified in 12 shoulders (75%). It was always distal to the TM tendon and visible during the deltopectoral approach. There was a clear separation between the TM proximally and dTMs tendon distally. At the humeral insertion, both tendons had a common epimyseal sheet around the teres major and inserted continuously at the humerus. The mean width of the dTMs tendon at the insertion was 13 ± 4 mm (range, 7-22 mm). The total lengths of the dTMs tendon and LD tendon were 40 ± 7 mm (range, 25-57 mm) and 69 ± 7 mm (range, 57-79 mm), respectively (p < 0.001). The dTMs muscle showed direct adhesions in ten shoulders (83%) with the LD muscle. CONCLUSIONS: This is the first macroscopic description of an additional distal slip of the teres major muscle. The dTMs has a separate (distal) but continuous (mediolateral) insertion at the humerus within a common epimyseal sheet around the TM. The dTMs tendon is visible during the deltopectoral approach and can therefore provide a lead structure, particularly in ventral LD transfers with the deltopectoral approach.