Neurologic complications in primary anatomic and reverse total shoulder arthroplasty: A review

MR neurography findings of brachial plexopathy following total shoulder arthroplasty

OBJECTIVES

To characterize nerve injury patterns following total shoulder arthroplasty (TSA).

METHODS

This retrospective study reviewed brachial plexus MR neurography (MRN) in patients with brachial plexopathy within 180 days post TSA from 2016 to 2023. Patients with pre-existing neurologic symptoms or without available electrodiagnostic testing (EDX) data were excluded. MRN findings were extracted from the original report and independently reviewed by a second, musculoskeletal fellowship trained radiologist.

RESULTS

A total of 27 patients (15F/12 M, mean age 67) were included. MRN and EDX-confirmed nerve injury localization matched in 13 patients, with nerve hyperintensity and/or enlargement identified in 7 cases at the plexus proper and 6 cases at the branch nerve level (suprascapular, axillary, radial, median). Nerve impingement by screw (n = 3) or extruded cement (n = 1) and mass effects including soft tissue edema (n = 1), hematoma (n = 2), or joint effusion (n = 2) were identified. MRN detected muscle denervation in 8 of 19 patients with EMG abnormalities, with a median TSA-to-MRN interval of 62.5 days (range, 19-95) versus 3 days (range, 2-155) in those without denervation on MRN (p = 0.003). Inter-rater reliability demonstrated substantial to almost perfect agreement for MRN assessments, except for cord hyperintensity. All patients were clinically followed up: 3 had complete symptomatic resolution and 21/27 reported partial improvement at a mean follow-up time of 25.5 months.

CONCLUSIONS

MRN findings closely correlated with EDX-confirmed clinical diagnoses in cases with MRN abnormalities. Additionally, MRN identified secondary findings, such as local mass effect on nerve segments, that can guide management.

Electrodiagnostic Assessment of Peri-Procedural Iatrogenic Peripheral Nerve Injuries and Rehabilitation

Iatrogenic nerve injuries are a significant concern for medical professionals and the patients affected. Peri-procedural nerve injuries result in functional deficits associated with pain and disability. The exact pathophysiology and etiology of peri-procedural nerve injuries are complex and often elude providers. The rates of injury to specific nerves are unclear and relate to both procedural and patient specific risk factors. Initial classification of the nerve injury into neurapraxia, axonotmesis, mixed nerve injury, or possible complete transection (neurotmesis) guides rehabilitation and management. Electrodiagnostic medical consultation at least four weeks post-injury, supplemented with nerve imaging (ultrasound and magnetic resonance imaging), can allow for accurate nerve injury classification. Supplemented with nerve imaging and detailed clinical evaluation, treatment, recovery and rehabilitation can be maximized. Recognizing nerves at risk associated with medical and surgical procedures can facilitate injury avoidance and early diagnosis. If a nerve injury is incomplete, in an optimized physiologic milieu (good glucose control, smoking cessation, etc.), there is a good potential for spontaneous (total or partial) improvement over time. Surgical referral should be considered for severe nerve injuries within 6 months, especially if there is concern for neurotmesis, and/or deteriorating nerve function. This review gives guidance for approaching peri-procedural peripheral nerve injuries, including the timing and the role of electrodiagnostic medical consultation including serial electrodiagnostic studies in management and rehabilitation.

The Evolution of Reverse Shoulder Arthroplasty: A Review of Complications and the Rising Concern of Overuse

Reverse shoulder arthroplasty (RSA) was initially developed to manage cuff tear arthropathy in elderly patients. It has since become increasingly popular due to its ability to provide pain relief, enhance stability, and improve function in various complex shoulder pathologies. This review examines the evolution of RSA, including its expanded indications for use, complications, and the rising concern of potential overuse. While RSA has shown significant benefits in selected cases, its growing application in younger and more active patients raises questions about long-term outcomes and durability. Complications such as instability, infection, baseplate failure, and scapular notching remain substantial challenges, particularly in revision cases. The article emphasises the need for cautious patient selection and evidence-based practice to avoid overuse and ensure optimal patient outcomes. Future high-quality research with extended follow-up is essential to better understand RSA's long-term efficacy and safety, particularly in diverse and younger patient populations.

Shoulder Arthroplasty: Preoperative Evaluation and Postoperative Imaging

Shoulder arthroplasty procedures have increased over the past few years. Several different arthroplasty options are available for varying indications, such as humeral head resurfacing, hemiarthroplasty, anatomical total shoulder arthroplasty, and reverse total shoulder arthroplasty, with ongoing modifications of prosthesis components and surgical techniques. Arthroplasty complications are encountered from the acute postoperative period to several years postoperatively. This article reviews the more common types of shoulder arthroplasties: their imaging appearances, multimodality imaging assessments for preoperative planning, and complications.

Perioperative deltoid pathologies in the setting of reverse shoulder arthroplasty: a narrative review

Background and Objective

The reverse total shoulder arthroplasty (RSA) is a widely used innovative procedure for managing shoulder pathologies like severe rotator cuff arthropathy, osteoarthritis with significant glenoid deformity, or proximal humerus fractures. RSA prosthesis designs utilize the deltoid muscle to bypass the role of the rotator cuff, and to generate most of the force required for shoulder elevation. As such, preoperative deltoid insufficiency or injury, as well as any intraoperative or postoperative complications involving the deltoid, can significantly impact patient outcomes, rehabilitation, and recovery following RSA. The aim of our review is to highlight the critical role of the deltoid muscle in RSA and discuss the different perioperative challenges that may impact its function and the overall success of the procedure.

Methods

The PubMed/MEDLINE database was screened for studies describing or reporting peri-operative deltoid or axillary nerve pathologies in the setting of RSA, from database inception until August of 2023. Articles were excluded if animals subjects were involved, or if they were written in the non-English language. Relevant search terms were used, and additional articles were retrieved from the reference lists of included articles.

Key Content and Findings

Ensuring the health and integrity of the deltoid muscle is essential for obtaining successful RSA outcomes. At the preoperative stage, deltoid insults can occur due to imbalances in glenohumeral musculature, pre-existing axillary nerve injury and subsequent deltoid atrophy, and concurrent viral infections. Remaining vigilant regarding diagnosis is important at this stage, as surgical treatment should be delayed until symptomatic resolution occurs. Intraoperatively, deltoid injuries can occur due to significant retraction, dissection, or iatrogenic fractures or nerve injuries. Conducting periodic intraoperative axillary nerve assessments and utilizing intraoperative nerve monitoring allow surgeons to potentially intervene in order to help minimize nerve damage. Postoperatively, pathologies can occur due to deltoid fatigue or acromial stress fractures. At that stage, educating patients about potential setbacks is important to set appropriate expectations and minimize injury risk.

Conclusions

Considering the importance of the deltoid in achieving proper RSA outcomes, significant attention should be garnered towards its integrity and health throughout the perioperative process.

A single-center retrospective chart review of percutaneous PNS for treatment of chronic shoulder pain

Objective

The present IRB-approved retrospective chart review describes the use of a 60-day PNS treatment for shoulder pain at a single center in 60 total consecutive patients.

Background

Chronic shoulder pain affects an increasing number of patients per year and is especially prevalent in elderly populations. Percutaneous peripheral nerve stimulation (PNS) treatment targeting the nerves of the shoulder has been shown to reduce pain in prospective clinical studies and in analysis of real-world data.

Methods

Data were extracted from the electronic medical records of patients who had previously undergone percutaneous PNS treatment for chronic shoulder pain. Demographic data and treatment characteristics were summarized alongside treatment outcomes.

Results

Overall, 84 % (49/58) of patients reported substantial (≥50 %) pain relief at the end-of-treatment. The records for 2 patients did not include patient-reported percent pain relief. The average indwelling period for leads (i.e., treatment period) was 57 days. Findings on treatment effectiveness were consistent when the patient population was stratified by cause of pain, duration living with pain, and presence of pain-modifying comorbidities. Stimulation paradigms were identified and categorized by the nerve target and stimulation frequency (e.g., motor stimulation, sensory stimulation, or bimodal stimulation).

Conclusions

These results indicate percutaneous PNS is an effective treatment for patients with various shoulder pain histories, and while all stimulation paradigms were effective at reducing pain, patients who received bimodal PNS reported the greatest pain relief. Key limitations of the study included heterogeneous shoulder pain etiologies among patients and sparse availability of long-term follow-up data. These data support existing real-world and prospective clinical evidence on the efficacy of 60-day PNS treatment at treating chronic pain and provide valuable insights into its use in clinical practice.

Iatrogenic Ulnar Nerve Neuropathy Following Reverse Total Shoulder Arthroplasty: Electrodiagnostic Findings in 18 Patients

Background A reverse total shoulder arthroplasty (RTSA) is often recommended for rotator cuff pathology and may be associated with a myriad of complications, including prosthetic instability, infection, humeral problems, and glenoid loosening. Neurological injuries following an RTSA are infrequent and are usually related to brachial plexus or proximal nerve injury in the affected arm. Iatrogenic ulnar nerve neuropathy is exceedingly rare. Aims This study describes the clinical and electrodiagnostic (EDX) features of 18 patients with ulnar nerve neuropathy complicating RTSA. Materials and methods All patients underwent EDX studies, and 14 had an ultrasound (US) study. Results All patients complained of numbness, tingling, hyperalgesia, and/or allodynia in the distribution of the ulnar nerve. Eight (44%) patients reported hand weakness, and one (6%) noted wasting of the intrinsic hand muscles. Decreased pinprick sensation in the ulnar nerve distribution was detected in all patients. Seventeen (94%) patients had weakness of the ulnar nerve-innervated intrinsic hand muscles. All patients had focal slowing of the motor conduction of the ulnar nerve across the elbow. Sensory potentials were either absent or of a low amplitude over the digital and/or dorsal cutaneous branch of the ulnar nerve in all patients. Twelve (86%) patients showed an increase in the cross-sectional area (CSA) of the ulnar nerve at the elbow; six (43%) had a hypoechoic ulnar nerve. Ulnar nerve neuropathy was confirmed at the elbow in all 18 patients. Of the 14 (78%) patients who underwent surgical intervention for ulnar nerve neuropathy following an RTSA, only four had complete symptom resolution. Conclusions Surgeons should be cognizant of ulnar nerve neuropathy as a potential complication of an RTSA and take precautions to avoid damage to the ulnar nerve intraoperatively. EDX and US studies should be performed to confirm and assess the site and severity of the injury.

Prevalence, management, and outcomes of nerve injury after shoulder arthroplasty: a case-control study and review of the literature

Background

Neurologic injury is a rare and potentially devastating complication of shoulder arthroplasty. Patients typically present with a mixed plexopathy or mononeuropathy, most commonly affecting the axillary and radial nerves. Given the paucity of studies available on the topic, our goal was to elucidate the prevalence of nerve injury after shoulder arthroplasty and to describe the treatment course and outcomes of neurologic injuries.

Methods

This is a retrospective case-control study performed at a single, urban, academic institution. Consecutive patients who underwent anatomic total shoulder arthroplasty (TSA) or reverse shoulder arthroplasty (RSA) by a single surgeon from 2014 to 2020 were reviewed, and patients with a documented nerve injury were identified. A control group of patients without nerve injury were selected in a 2:1 ratio controlling for age and procedure type (TSA vs. RSA; primary vs. revision). Data collected included demographics, comorbidities as per the Charlson Comorbidity Index, radiographic evaluations, surgical and implant details, patient-reported outcome measures, and perioperative complications.

Results

Of 923 patients, 33 (3.6%) sustained an iatrogenic nerve injury: 10 (2.1%) after TSA, 23 (5.0%) after RSA, and 3 (7.8%) after revision arthroplasty. Axillary mononeuropathy was most common (42%), followed by brachial plexopathies (18%). There was no significant difference in age, sex, race, body mass index, and preoperative diagnoses between groups. Patients with nerve injury had fewer comorbidities (Charlson Comorbidity Index <3, 33 vs. 65%, P<.001). Patients with nerve injury had higher rates of cervical spine pathology (15 vs. 6%; P = .15) and increased postoperative lateralization (8.9 mm [7.2] vs. 5.5 mm [7.3]; P<.06). The majority (91%) were managed with observation alone. Three (9%) underwent an additional procedure: carpal tunnel release (1, 3%), ulnar nerve decompression (1, 3%), and ulnar nerve transposition (1, 3%) for peripheral compressive neuropathies. At the final follow-up, 19 (57%) nerves fully recovered, and 14 (43%) showed mild residual sensorimotor dysfunction. The mean time to first sign of recovery and ultimate recovery were 11 (7.2) and 36 (23.5) weeks, respectively. At the final follow-up, patients with nerve injury performed worse on patient-reported outcomes, including visual analog score pain (2.2 vs. 1.0, P<.001), American Shoulder and Elbow Surgeons score (67.8 vs. 84.8, P<.001), and Single Assessment Numeric Evaluation scores (62 vs. 77, P = .009).

Discussion

Nerve injury after shoulder arthroplasty is rare, occurring in 3.6% of our patient population. Axillary mononeuropathy and brachial plexopathies are the most common. Most patients can be managed expectantly with observation and will recover at least partial nerve function, although clinical outcomes remain inferior to those without nerve complication.

Incidence, Risk Factors, Prevention, and Management of Peripheral Nerve Injuries Following Shoulder Arthroplasty

In this article, the authors review the incidence and causes of iatrogenic peripheral nerve injuries following shoulder arthroplasty and provide preventative measures to decrease nerve injury rate and management options. They describe common direct and indirect causes of injury such as laceration and retractor use versus arm positioning and lengthening, respectively. Preventative measures include an understanding of anatomy and high-risk locations in the shoulder, minimizing extreme ranges of arm motion and utilization of intraoperative nerve monitoring. Lastly, the authors review diagnosis and management of neurologic symptoms including how and when to use electrodiagnostic studies, nerve grafts, transfers, or muscle/tendon transfers.

Lateralization in Reverse Shoulder Arthroplasty

Indications for Reverse Shoulder Arthroplasty (RSA) have been extended over the last 25 years, and RSA has become the most frequently implanted shoulder arthroplasty worldwide. The initial Grammont design with medialization of the joint center of rotation (JCOR), placement of the JCOR at the bone–implant interface, distalization and semi-constrained configuration has been associated with drawbacks such as reduced rotation and range of motion (ROM), notching, instability and loss of shoulder contour. This review summarizes new strategies to overcome these drawbacks and analyzes the use of glenoid-sided, humeral-sided or global bipolar lateralization, which are applied differently by surgeons and current implant manufacturers. Advantages and drawbacks are discussed. There is evidence that lateralization addresses the initial drawbacks of the Grammont design, improving stability, rates of notching, ROM and shoulder contour, but the ideal extent of lateralization of the glenoid and humerus remains unclear, as well as the maximal acceptable joint reaction force after reduction. Overstuffing and spine of scapula fractures are potential risks. CT-based 3D planning as well as artificial intelligence will help surgeons with planning and execution of appropriate lateralization in RSA. Long-term follow-up of lateralization with new implant designs and implantation strategies is needed.