A multicenter, randomized controlled trial comparing a second-generation uncemented trabecular metal-backed vs. cemented polyethylene glenoid component in total shoulder arthroplasty: 5-year results.

BACKGROUND: Previously, we reported early (2-year) findings from a randomized controlled trial comparing a second-generation uncemented trabecular metal-backed (TM) glenoid vs. cemented polyethylene glenoid (POLY) in patients undergoing a total shoulder arthroplasty. The purpose of the current study is to report disease-specific quality of life, clinical, patient-reported, and radiographic outcomes at midterm (5-year) from this trial. METHODS: Five surgeons from 3 centers participated. Patients 18-79 years with a primary diagnosis of glenohumeral osteoarthritis were screened for eligibility. Randomization to an uncemented TM or cemented POLY glenoid was performed intra-operatively after adequate bone stock was confirmed. Study intervals were baseline, 2- and 5-year postoperative. The primary outcome was the Western Ontario Osteoarthritis Shoulder (WOOS) quality of life score. Secondary outcomes included the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, EuroQol-5 Dimensions, and 12-Item Short Form Health Survey scores and clinical and radiographic examinations. Radiographic images were reviewed for metal debris according to Endrizzi. Mixed effects repeated measures analysis of variance for within- and between-group comparisons were performed. RESULTS: Of the 104 patients who consented, 93 were randomized (46 TM; 47 POLY). There were no differences between groups at baseline (TM: mean age 66.5 years [standard deviation (SD) 6.4], 24 male and 22 female; and POLY: mean age 68.4 years [SD 5.5], 23 male / 24 female). Mean (SD) WOOS scores at baseline and 2 and 5 years were as follows: TM, 32 (21), 92 (13), and 93 (11); POLY, 27 (15), 93 (11), and 93 (10), respectively. No statistical or clinically relevant differences were noted with patient-reported outcomes between groups. Metal debris was observed in 11 (23.9%) patients, but outcomes were not negatively impacted, and debris severity was minor (grades 1 and 2). Complication rates were similar between groups (TM: 7 of 46 [15.2%], and POLY: 8 of 47 [17.0%]; P = .813). No aseptic glenoid failures were reported, but 1 patient in the TM group required revision because of infection. CONCLUSIONS: Our short-term (2-year) findings were maintained with longer follow-up. At 5 years postoperation, there were no statistically or clinically significant differences between an uncemented second-generation TM glenoid and a cemented polyethylene glenoid with respect to disease-specific quality of life or patient-reported outcomes. No glenoid implant failures were reported, and complication rates were similar between groups. Only one complication was glenoid related (1 infection in the TM group). Metal debris was observed in 23.9% of patients with a TM glenoid but did not negatively influence implant survival, patient-reported outcomes, or shoulder function.

Thumb basal joint arthritis in 2023.

Thumb carpometacarpal or basal joint arthritis is the second most common location for osteoarthritis in the hand. It mainly affects women over 50years of age. Basal joint arthritis causes pain, loss of strength during pinch grips, and eventually stiffness and progressive deformity of the thumb column. Conservative treatment must be implemented first. It aims to spare the joint by using standardized methods. It must be initiated as soon as pain starts, not once the deformity has settled in. There is broad agreement that surgery is indicated when pain relief is not achieved after at least 6months of conservative treatment. The available surgical techniques can be classified as joint-sparing (extra-articular) and joint-sacrificing (intra-articular). The former consists of trapeziometacarpal stabilizing ligament reconstruction, subtraction osteotomy of the first metacarpal and thumb carpometacarpal denervation. The latter consists of trapeziometacarpal fusion, trapeziectomy (and its variants) and implant arthroplasty. Except in very specific cases, trapeziectomy and trapeziometacarpal implant arthroplasty with a total joint prosthesis or an interposition implant are the two main surgical techniques for treating basal joint arthritis. After reviewing the pathophysiology and the diagnosis of thumb basal joint arthritis, we will provide an overview of the available treatment options, with emphasis on the accepted surgical strategies in 2023. LEVEL OF EVIDENCE: III.

Long-term results of the AptisTM total distal radioulnar joint prosthesis after previous failed surgical procedures.

We present a prospective study with the results of ten Aptis total distal radioulnar joint replacements in patients who had one to five previous operations. The mean postoperative follow-up was 9.7 years (range 3-14.7). The mean postoperative range of motion of the wrist improved by 9° for extension, 15° for flexion, 10° for pronation and 14° for supination, achieving values equivalent to 88%, 78%, 97% and 88% of those of the non-operated hand. There were minimal changes in radial and ulnar deviations. Grip strength improved by 7 kg, pain decreased by 8 points, QuickDASH and Mayo wrist scores improved by 51 and 53 points, respectively. Two implants had radiolucency less than 1 mm. Serum titanium ion levels were slightly elevated in two patients. Three prostheses required revision surgery for heterotopic ossification, a prominent radial screw and a periprosthetic fracture. No prostheses were removed. Six patients returned to their former professional activities and four patients adapted their jobs.Level of evidence: IV.

Automated Shoulder Implant Manufacturer Detection using Encoder Decoder based Classifier from X-ray Images.

Total shoulder arthroplasty is the process of replacing the damaged ball and socket joint in the shoulder with a prosthesis made with polyethylene and metal components. The prosthesis helps to restore the normal range of motion and reduce pain, enabling the patient to return to their daily activities. These implants may need to be replaced over the years due to damage or wear and tear. It is a tedious and time-consuming process to identify the type of implant if medical records are not properly maintained. Artificial intelligence systems can speed up the treatment process by classifying the manufacturer and model of the prosthesis. We have proposed an encoder-decoder based classifier along with the supervised contrastive loss function that can identify the implant manufacturer effectively with increased accuracy of 92% from X-ray images overcoming the class imbalance problem.

Treatment of Glenoid Wear with the Use of Augmented Glenoid Components in Total Shoulder Arthroplasty: A Scoping Review.

¼ Treatment of glenoid bone loss continues to be a challenge in total shoulder arthroplasty (TSA). Although correcting glenoid wear to patient's native anatomy is desirable in TSA, there is lack of consensus regarding how much glenoid wear correction is acceptable and necessary in both anatomic and reverse TSA.¼ Use of augmented glenoid components is a relatively new treatment strategy for addressing moderate-to-severe glenoid wear in TSA. Augmented glenoid components allow for predictable and easy correction of glenoid wear in the coronal and/or axial planes while at the same time maximizing implant seating, improving rotator cuff biomechanics, and preserving glenoid bone stock because of off-axis glenoid reaming.¼ Augmented glenoid components have distinct advantages over glenoid bone grafting. Glenoid bone grafting is technically demanding, adds to the surgical time, and carries a risk of nonunion and graft resorption with subsequent failure of the glenoid component.¼ The use of augmented glenoid components in TSA is steadily increasing with easy availability of computed tomography-based preoperative planning software and guidance technology (patient-specific instrumentation and computer navigation).¼ Although different augment designs (full wedge, half wedge, and step cut) are available and a particular design may provide advantages in specific glenoid wear patterns to minimize bone removal (i.e. a half wedge in B2 glenoids), there is no evidence to demonstrate the superiority of 1 design over others.

Trial of Vancomycin and Cefazolin as Surgical Prophylaxis in Arthroplasty.

BACKGROUND: The addition of vancomycin to beta-lactam prophylaxis in arthroplasty may reduce surgical-site infections; however, the efficacy and safety are unclear. METHODS: In this multicenter, double-blind, superiority, placebo-controlled trial, we randomly assigned adult patients without known methicillin-resistant Staphylococcus aureus (MRSA) colonization who were undergoing arthroplasty to receive 1.5 g of vancomycin or normal saline placebo, in addition to cefazolin prophylaxis. The primary outcome was surgical-site infection within 90 days after surgery. RESULTS: A total of 4239 patients underwent randomization. Among 4113 patients in the modified intention-to-treat population (2233 undergoing knee arthroplasty, 1850 undergoing hip arthroplasty, and 30 undergoing shoulder arthroplasty), surgical-site infections occurred in 91 of 2044 patients (4.5%) in the vancomycin group and in 72 of 2069 patients (3.5%) in the placebo group (relative risk, 1.28; 95% confidence interval [CI], 0.94 to 1.73; P = 0.11). Among patients undergoing knee arthroplasty, surgical-site infections occurred in 63 of 1109 patients (5.7%) in the vancomyin group and in 42 of 1124 patients (3.7%) in the placebo group (relative risk, 1.52; 95% CI, 1.04 to 2.23). Among patients undergoing hip arthroplasty, surgical-site infections occurred in 28 of 920 patients (3.0%) in the vancomyin group and in 29 of 930 patients (3.1%) in the placebo group (relative risk, 0.98; 95% CI, 0.59 to 1.63). Adverse events occurred in 35 of 2010 patients (1.7%) in the vancomycin group and in 35 of 2030 patients (1.7%) in the placebo group, including hypersensitivity reactions in 24 of 2010 patients (1.2%) and 11 of 2030 patients (0.5%), respectively (relative risk, 2.20; 95% CI, 1.08 to 4.49), and acute kidney injury in 42 of 2010 patients (2.1%) and 74 of 2030 patients (3.6%), respectively (relative risk, 0.57; 95% CI, 0.39 to 0.83). CONCLUSIONS: The addition of vancomycin to cefazolin prophylaxis was not superior to placebo for the prevention of surgical-site infections in arthroplasty among patients without known MRSA colonization. (Funded by the Australian National Health and Medical Research Council; Australian New Zealand Clinical Trials Registry number, ACTRN12618000642280.).

Wrist arthrodesis combined with a bulk bone allograft for implant loosening after total wrist arthroplasty: A case report.

Total wrist arthroplasty (TWA) is a challenging procedure for wrist joints severely destroyed by rheumatoid arthritis. The most common postoperative complication of TWAs is the loosening of the carpal component. Revision surgeries for failed TWAs can be complicated owing to severe bone loss and concomitant soft-tissue problems. Here, we report a case (68-year-old woman with a history of rheumatoid arthritis for 24 years) of severe aseptic loosening of semi-constrained TWA and its salvage surgery. During the primary arthroplasty procedure, severe instability at the second through fifth carpometacarpal joints was observed and arthrodesis of these joints was required. The radiographs obtained 9 months after surgery showed loosening of the carpal component. Subsequently, she suffered a stroke, resulting in a loss of follow-up, and higher stress was loaded on her upper extremities during standing and walking. In the radiograph taken at her revisit 25 months after the primary surgery, the subsidence of the carpal component progressed and loosening of the radial component was observed. Total wrist arthrodesis was performed using a bulk bone allograft of the femoral head, combined with a penetrating Wrist Fusion Rod®. Rapid bone union was achieved without soft-tissue irritation. We conclude that wrist arthrodesis with a bulk bone allograft combined with an intramedullary nail is a reasonable option for failed total wrist arthroplasty.

The semiconstrained DRUJ prosthesis: blessing or curse?

PURPOSE: There are numerous operative procedures to treat osteoarthritic changes or a significant instability of the distal radioulnar joint (DRUJ). The key problem of most methods is the destabilization of the forearm leading to secondary painful impingement between the radius and ulna, as well as a significant limitation of forearm rotation. The Aptis-Prosthesis designed by Scheker represents a complete substitute for the DRUJ. It is mostly used after the failure of various treatment options to solve the primary problems (arthritis, instability). We have used this type of prosthesis mostly after multiple operative treatments for more than 25 years. METHODS: In the following retrospective study, we analyzed the data of patients that received an Aptis-prosthesis between 2016 and 2021. We have implanted this prosthesis in 13 cases (11 female, 2 male). Routinely, we document the clinical outcome concerning range of motion (ROM), grip strength, and pain according to numeric rate scaling (NRS) after more than 12 months (month 12-24). In addition, complications, osseous changes, and the rate of loosening of the prosthesis were registered. Furthermore, DASH-Score and patients ' satisfaction were evaluated. Also-as with other implants-follow-up x-rays were performed. RESULTS: Removal or significant revision of any of the prostheses was not needed. The ROM was 68.1° ± 19.7° for pronation and 72.3° ± 20.9° for supination, grip strength amounted to 27.7 kg ± 11.0 kg equaling 83% of the contralateral side. NRS was 0 at rest and 1.2 (0-2) under weight-bearing. A lysis margin of the radial tap was noted in the radiological examination in 2 patients but without any signs of loosening. The DASH-Score added up to 31.8 ± 13.8 (13-55). All patients were satisfied or very satisfied having this implant. CONCLUSION: The semiconstrained Aptis-prosthesis is a safe and efficient treatment option after failed DRUJ surgeries. It is striking that of the 20 implanted prostheses no significant revision or explantations were necessary over a period of 25 years.

Wrist Arthritis and Arthrodesis: Preserving Function, Minimizing Problems.

Wrist arthritis is a common condition with numerous causes and presentations. Several management options exist, and treatment should be individualized based on patient age, comorbidities, occupation, duration of symptoms, and failed treatment modalities. Arthroscopy and denervation are appealing because of shorter recovery time and preservation of motion, but duration of effectiveness varies between patients. Patients who fail these smaller procedures or those with pancarpal arthrosis are treated effectively with total wrist arthrodesis or total wrist arthroplasty in lower-demand patients. This article reviews causes and patterns of wrist arthritis and discusses treatment strategies aimed at preserving function and minimizing complications.

What to expect after revision shoulder arthroplasty? A comprehensive review of the literature.

The number of shoulder arthroplasties has increased tremendously over the last twenty years, creating a proportional increase in complications rates and revision. Shoulder arthroplasty surgeon should have a clear understanding of the reasons for failure based on the specific index procedure that was performed. The main challenge includes the need for component removal and managing glenoid and humeral bone defects. This manuscript aims to outline the most common indications for revision surgery and treatment options based on a careful and detailed review of the available literature.  This paper should help the surgeon in patient evaluation and selection of the optimal procedure for an individual patient.

Is the risk of chronic pain after total temporomandibular joint replacement independent of its indications? A prospective cohort study.

Chronic pain is a possible long-term complication after alloplastic temporomandibular joint reconstruction (TMJR). This study was developed to evaluate various subjective and objective measurements to determine the presence and degree of TMJ pain in patients treated with TMJR regardless of the indication for the operation. A prospective, single-centre study was performed. Data on 36 patients (56 TMJR) were collected preoperatively and at follow up two to three years postoperatively. The primary outcome variable was subjective TMJ pain (none/mild, moderate/severe) at follow up. The predictor variables were objective pressure pain thresholds (PPTs) at the ipsilateral joint(s) and muscle(s), functional parameters (incisal range of motion, maximum voluntary clenching), subjective oral health-related quality of life (OHRQoL), and demographic and surgical variables. The number of patients with moderate/severe pain decreased from 17 preoperatively to 10 at follow up. Self-reported TMJ pain was significantly reduced in the entire group (p = 0.001). Patients with moderate/severe pain at follow up were more restricted in their OHRQoL but did not differ in PPT and functional parameters from the no/mild pain group. Moderate/severe TMJ pain at follow up was associated with unilateral TMJR and more preoperative pain. This study provides preliminary evidence that despite good pain reduction in most patients, persistent pain after TMJR is common and, in rare cases, may even worsen regardless of the original diagnosis. At follow up there was a close relation between OHRQoL and TMJ pain. TMJ pain after TMJR cannot be confirmed by objective measurement methods (PPTs and functional parameters).

Short-term functional outcomes of reverse shoulder arthroplasty following three-dimensional planning is similar whether placed with a standard guide or patient-specific instrumentation.

BACKGROUND: Preoperative assessment of the glenoid and surgical placement of the initial guidewire are important in implant positioning during reverse total shoulder arthroplasty (rTSA). Three-dimensional (3D) computed tomography and patient-specific instrumentation (PSI) have improved the placement of the glenoid component, but the impact on clinical outcomes remains unclear. The purpose of this study was to compare short-term clinical outcomes after rTSA based on an intraoperative technique for central guidewire placement in a cohort of patients who had preoperative 3D planning. METHODS: A retrospective matched analysis was performed from a multicenter prospective cohort of patients who underwent rTSA with preoperative 3D planning and a minimum of 2-year clinical follow-up. Patients were divided into 2 cohorts based on the technique used for glenoid guide pin placement: (1) standard manufacture guide (SG) that was not customized or (2) PSI. Patient-reported outcomes (PROs), active range of motion, and strength measures were compared between the groups. The American Shoulder and Elbow Surgeons score was used to assess the minimum clinically important difference, substantial clinical benefit, and patient acceptable symptomatic state. RESULTS: One hundred seventy-eight patients met the study criteria: 56 underwent SGs and 122 underwent PSI. There was no difference in PROs between cohorts. There were no significant differences in the percentage of patients who achieved an American Shoulder and Elbow Surgeons minimum clinically important difference, substantial clinical benefit, or patient acceptable symptomatic state. Improvements in internal rotation to the nearest spinal level (P < .001) and at 90° (P = .002) were higher in the SG group, but likely explained by differences in glenoid lateralization used. Improvements in abduction strength (P < .001) and external rotation strength (P = .010) were higher in the PSI group. CONCLUSION: rTSA performed after preoperative 3D planning leads to similar improvement in PROs regardless of whether an SG or PSI is used intraoperatively for central glenoid wire placement. Greater improvement in postoperative strength was observed with the use of PSI, but the clinical significance of this finding is unclear.

[Instabilities of the Thumb Carpometacarpal Joint: Our Surgical Outcomes]. / Nestability karpometakarpálního kloubu palce ruky: nase výsledky operacního resení.

PURPOSE OF THE STUDY Carpometacarpal (CMC) instabilities of the thumb joint occur after injuries or due to joint overload in patients with congenital joint hypermobility. They are often undiagnosed and, if left untreated, are the basis for the development of rhizarthrosis in young individuals. The authors present the results of the Eaton-Littler technique. MATERIAL AND METHODS The authors present a set of 53 CMC joints of patients with an average age of 26.8 years (15-43 years) operated on in the years 2005-2017. Post-traumatic conditions were found in 10 patients and in 43 cases instability was caused by hyperlaxity, also demonstrated in other joints. The operation was performed from the Wagner's modified anteroradial approach. After the operation, a plaster splint was applied for 6 weeks, after which rehabilitation (magnetotherapy, warm-up) began. Patients were evaluated using the VAS (pain at rest and during exercise), DASH score in the work module, and subjective evaluation (no difficulties, difficulties not limiting normal activities, and difficulties limiting normal activities) before surgery and 36 months after surgery. RESULTS During the preoperative assessment, the average VAS value was 5.6 at rest and 8.3 during exercise. During the VAS assessment at rest, the values at 6, 12, 24 and 36 months after surgery were 5.6, 2.9, 0.9, 1, 2 and 1.1. When evaluated in the given intervals under load, the detected values were 4.1, 2, 2.2 and 2.4. The DASH score in the work module was 81.2 before surgery, 46.3 at 6 months, 15.2 at 12 months, 17.3 at 24 months, and 18.4 at 36 months after surgery. In the subjective self-assessment made at 36 months after surgery, 39 patients (74%) assessed their condition as having no difficulties, ten patients (19%) reported difficulties that did not limit normal activities, and four patients (7%) reported difficulties limiting normal activities. DISCUSSION Most authors present the results of their surgeries in patients with post-traumatic joint instability, and they report excellent results at two to six years after surgery. There is a negligible number of studies addressing instabilities in patients with instability caused by hypermobility. When using the conventional method described by the authors in 1973, our results of the evaluation performed at 36 months after surgery are comparable to those reported by other authors. We are well aware of the fact that this is a short-term follow-up and that this method does not prevent developing degenerative changes in the case of long-term follow-up, but reduces clinical difficulties and may delay the development of severe rhizarthrosis in young individuals. CONCLUSIONS CMC instability of the thumb joint is a relatively common disorder, although not all individuals experience clinical difficulties. In the case of difficulties, the instability needs to be diagnosed and treated as this is how the development of early rhizarthrosis in the predisposed individuals can be prevented. Our conclusions suggest a possibility of a surgical solution with good results. Key words: carpometacarpal thumb joint, thumb CMC joint, carpometacarpal thumb instability, joint laxity, rhizarthrosis.

Dual mobility prosthesis for trapeziometacarpal osteoarthritis: results from a prospective study of 55 prostheses.

This prospective study evaluated outcomes after trapeziometacarpal joint replacement with a dual mobility prosthesis (Touch®) in 55 thumbs (52 patients) with a mean follow-up of 25 months (range 12-36). Pre- and postoperative assessments included pain, range of motion, the Kapandji index, pinch- and grip strength, as well as functional scores and radiological parameters. Mean preoperative metacarpophalangeal joint hyperextension of 19° (range 15°-28°) showed a significant correction after 1 year with a mean value of 2° (range 0°-5°). Mean Quick Disabilities of the Hand, Shoulder and Arm score was 14 (range 6-28), and Michigan Hand Questionnaire 82 (range 67-92). No revisions due to infection, loosening, dislocation or material failure occurred during follow-up. The dual mobility trapeziometacarpal joint prosthesis was a reliable treatment option to decrease pain, improve motion, strength and pre-existing metacarpophalangeal joint hyperextension at short-term follow-up.Level of evidence: IV.

[Update: endoprosthetics on the ankle joint]. / Update: Endoprothetik am oberen Sprunggelenk.

The ankle joint has to bear the entire body weight on a relatively small joint surface. Incongruities, instabilities and deformities lead to painful arthrosis and considerable restrictions in everyday life. For many years, arthrodesis has proven to be the gold standard for end stage arthrosis; however, considering modern endoprostheses for the ankle joint it is no longer appropriate to offer only arthrodesis. The very good results of the 3rd generation 3­component prostheses and the 4th generation 2­component prostheses show how much the surgical treatment options for the ankle joint are currently changing. The simplified implantation techniques enable access to arthroplasty of the ankle joint for a broader spectrum of surgeons and explain the increasing implantation rates in recent years. Decisive for postoperative success are correct planning with knowledge of the leg axes and foot position, correct patient selection and exact surgical placement of the components.

Two-year outcomes of the reverse humeral reconstruction prosthesis.

BACKGROUND: Extensive proximal humeral bone loss in the setting of shoulder arthroplasty represents a difficult challenge for the treating surgeon. Achieving adequate fixation with standard humeral prostheses can be problematic. Allograft-prosthetic composites are a viable solution for this problem; however, high rates of complications have been reported. Modular proximal humeral replacement systems are another potential solution, but there is a paucity of outcome data on these implants. This study reports the 2-year minimum follow-up outcomes and complications of a single system reverse proximal humeral reconstruction prosthesis (RHRP) for patients with extensive proximal humeral bone loss. METHODS: We retrospectively reviewed all patients with minimum 2-year follow-up who underwent implantation of an RHRP for either (1) failed shoulder arthroplasty or (2) proximal humerus fracture with severe bone loss (Pharos 2 and 3) and/or sequelae thereof. Forty-four patients met inclusion criteria (average age 68.3 ± 13.1 years). The average follow-up was 36.2 ± 12.4 months. Demographic information, operative data, and complications were recorded. Pre- and postoperative range of motion (ROM), pain, and outcome scores were assessed and compared to the minimal clinically important difference (MCID) and substantial clinical benefit (SCB) for primary rTSA where available. RESULTS: Of the 44 RHRPs evaluated, 93% (n = 39) had undergone prior surgery and 70% (n = 30) were performed for failed arthroplasty. ROM improved significantly in abduction by 22° (P = .006) and forward elevation by 28° (P = .003). Average pain on a daily basis and pain at worst improved significantly, by 2.0 points (P < .001) and 2.7 points (P < .001), respectively. Mean Simple Shoulder Test score improved by 3.2 (P < .001), Constant score by 10.9 (P = .030), American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score by 29.7 (P < .001), University of California, Los Angeles (UCLA), score by 10.6 (P < .001), and Shoulder Pain and Disability Index score by 37.4 (P < .001). A majority of patients achieved the MCID for all outcome measures assessed (56%-81%). The SCB was exceeded by half of patients for forward elevation and the Constant score (50%), and exceeded by the majority of patients for the ASES score (58%) and UCLA score (58%). The complication rate was 28%; the most common complication was dislocation requiring closed reduction. Notably, there were no occurrences of humeral loosening requiring revision surgery. DISCUSSION: These data demonstrate that the RHRP resulted in significant improvements in ROM, pain, and patient-reported outcome measures, without the risk of early humeral component loosening. RHRP represents another potential solution for shoulder arthroplasty surgeons when addressing extensive proximal humerus bone loss.

Characterizing moment arms of the coracobrachialis and short head of biceps in native shoulders and after reverse total shoulder arthroplasty during elevation and rotation: a modeling study.

BACKGROUND: Reverse total shoulder arthroplasty (RTSA) alters the line of action of muscles around the glenohumeral joint. The effects of these changes have been well characterized for the deltoid, but there is limited information regarding the biomechanical changes to the coracobrachialis (CBR) and short head of biceps (SHB). In this biomechanical study, we investigated the changes to the moment arms of the CBR and SHB due to RTSA using a computational model of the shoulder. METHODS: The Newcastle Shoulder Model, a pre-validated upper-extremity musculoskeletal model, was used for this study. The Newcastle Shoulder Model was modified with bone geometries obtained from 3-dimensional reconstructions of 15 nondiseased shoulders, constituting the native shoulder group. The Delta XTEND prosthesis, with a glenosphere diameter of 38 mm and polyethylene thickness of 6 mm, was virtually implanted in all the models, creating the RTSA group. Moment arms were measured using the tendon excursion method, and muscle length was calculated as the distance between the muscle's origin and insertion points. These values were measured during 0°-150° of abduction, forward flexion, scapular-plane elevation, and -90° to 60° of external rotation-internal rotation with the arm at 20° and 90° of abduction. Statistical comparisons between the native and RTSA groups were analyzed using 1-dimensional statistical parametric mapping (spm1D). RESULTS: Forward flexion moment arms showed the greatest increase between the RTSA group (CBR, 25.3 ± 4.7 mm; SHB, 24.7 ± 4.5 mm) and native group (CBR, 9.6 ± 5.2 mm; SHB, 10.2 ± 5.2 mm). The CBR and SHB were longer in the RTSA group by maximum values of 15% and 7%, respectively. Both muscles had larger abduction moment arms in the RTSA group (CBR, 20.9 ± 4.3 mm; SHB, 21.9 ± 4.3 mm) compared with the native group (CBR, 19.6 ± 6.6 mm; SHB, 20.0 ± 5.7 mm). Abduction moment arms occurred at lower abduction angles in the RTSA group (CBR, 50°; SHB, 45°) than in the native group (CBR, 90°; SHB, 85°). In the RTSA group, both muscles had elevation moment arms until 25° of scapular-plane elevation motion, whereas in the native group, the muscles only had depression moment arms. Both muscles had small rotational moment arms that were significantly different between RTSA and native shoulders during different ranges of motion. CONCLUSION: Significant increases in elevation moment arms for the CBR and SHB were observed in RTSA shoulders; these increases were most pronounced during abduction and forward elevation motions. RTSA also increased the lengths of these muscles.

Anterior deltoid muscle reflection using a deltopectoral approach is safe and does not influence outcome of reverse shoulder arthroplasty.

BACKGROUND: The deltopectoral approach is well accepted for shoulder arthroplasty procedures. The extended deltopectoral approach with detachment of the anterior deltoid from the clavicle allows increased joint exposure and can protect the anterior deltoid from traction injury. The efficacy of this extended approach has been demonstrated in anatomic total shoulder replacement surgery. However, this has not been shown in reverse shoulder arthroplasty (RSA). The primary aim of this study was to evaluate the safety of the extended deltopectoral approach in RSA. The secondary aim was to evaluate the performance of the deltoid reflection approach in terms of complications and surgical, functional, and radiologic outcomes up to 24 months after surgery. METHODS: A prospective, nonrandomized comparative study was performed between January 2012 and October 2020 including 77 patients in the deltoid reflection group and 73 patients in the comparative group. The decision for inclusion was based on patient and surgeon factors. Complications were recorded. Patients were followed up for ≥24 months to evaluate their shoulder function and undergo ultrasound evaluation. Functional outcome measures included the Oxford Shoulder Score, Disabilities of the Arm, Shoulder and Hand score, American Shoulder and Elbow Surgeons score, pain intensity (rated on visual analog scale [VAS] from 0 to 100), and range of motion (forward flexion, abduction, and external rotation). A regression analysis was performed to evaluate any factors of influence on the VAS score. RESULTS: There were no significant differences in the complication rate between the 2 groups (14.5% in deltoid reflection group and 13.8% in comparative group, P = .915). Ultrasound evaluation was available in 64 patients (83.1%), and no proximal detachment was observed. In addition, there were no significant differences in functional outcome measures both preoperatively and at 24 months after surgery between the groups assessed based on the mean VAS pain score, Oxford Shoulder Score, Disabilities of the Arm, Shoulder and Hand score, American Shoulder and Elbow Surgeons score, forward flexion, abduction, and external rotation. Adjustment for possible confounders in a regression model indicated that only prior surgery significantly influenced the VAS pain score after surgery (P = .031; 95% confidence interval, 0.574-11.67). Deltoid reflection (P = .068), age (P = .466), sex (P = .936), use of glenoid graft (P = .091), prosthesis manufacturer (P = .382), and preoperative VAS score (P = .362) were not of influence. DISCUSSION: The results of this study show that an extended deltopectoral approach for RSA is safe. Selected reflection of the anterior deltoid muscle improved exposure and prevented anterior deltoid muscle injury followed by reattachment. Patients had similar functional scores preoperatively and at 24 months postoperatively compared with a comparative group. Furthermore, ultrasound evaluation showed intact reattachments.