Revision Shoulder Arthroplasty: Predictors of Subsequent Revision Surgery and Economic Burden amongst Medicare Beneficiaries.

BACKGROUND: Revision shoulder arthroplasty continues to add an increasing burden on patients and the healthcare system. This study aimed to delineate long-term shoulder arthroplasty revision incidence, quantify associated Medicare spending, and identify relevant predictors of both revision and spending. METHODS: The complete 2016-2022(Q3) Medicare fee-for-service inpatient and outpatient claims data was analyzed. Patients receiving a primary total shoulder arthroplasty for osteoarthritis, rotator cuff pathology, or inflammatory arthropathy were included and subsequent ipsilateral revision surgeries were identified. The time to revision was modeled using the Prentice, Williams, and Peterson Gap Time Model. Medicare spending within 90 days post-discharge was modeled using a generalized linear model. The analysis was subdivided by index procedure type: anatomic total shoulder arthroplasty (TSA) and reverse shoulder arthroplasty (RSA). RESULTS: A total of 82,949 primary TSAs and 172,524 RSAs were identified. Compared to index TSA cases, index RSA cases had a lower first revision rate in an observation window of nearly 7 years (1.9% vs. 3.5%, p<0.001), but a higher rate of second (11.4% vs. 4.9%, p<0.001) as well as third revision (13.8% vs. 13.8%, p=0.449). TSA spending was significantly lower than RSA spending for the index procedure ($21,531 vs. $23,267, p<0.001), first ($23,096 vs. $26,414, p<0.001), and second ($25,060 vs. $29,983, p<0.001) revision. There was no statistically significant difference in third revision between TSA and RSA groups ($31,313 vs. $30,829, p=0.860). Age, sex, race, and rheumatoid arthritis were among the top predictors of revisions. Top predictors of Medicare spending included having a non-osteoarthritis surgical indication, a hospital stay of three or more days, a discharge to a setting other than home, malnutrition, dementia, stroke, major kidney diseases, and being operated on in a teaching hospital. CONCLUSION: Compared with TSA, RSA was associated with a lower first revision rate, but a higher subsequent revision rate. An index RSA procedure was also associated with higher initial Medicare spending as well as subsequent revision surgery spending compared with an index TSA procedure. Demographics and comorbid medical conditions were among the top predictors of revisions, while procedure-related factors predicted Medicare spending.

Utility of Machine Learning, Natural Language Processing, and Artificial Intelligence in Predicting Hospital Readmissions After Orthopaedic Surgery: A Systematic Review and Meta-Analysis.

BACKGROUND: Numerous applications and strategies have been utilized to help assess the trends and patterns of readmissions after orthopaedic surgery in an attempt to extrapolate possible risk factors and causative agents. The aim of this work is to systematically summarize the available literature on the extent to which natural language processing, machine learning, and artificial intelligence (AI) can help improve the predictability of hospital readmissions after orthopaedic and spine surgeries. METHODS: This is a systematic review and meta-analysis. PubMed, Embase and Google Scholar were searched, up until August 30, 2023, for studies that explore the use of AI, natural language processing, and machine learning tools for the prediction of readmission rates after orthopedic procedures. Data regarding surgery type, patient population, readmission outcomes, advanced models utilized, comparison methods, predictor sets, the inclusion of perioperative predictors, validation method, size of training and testing sample, accuracy, and receiver operating characteristics (C-statistic), among other factors, were extracted and assessed. RESULTS: A total of 26 studies were included in our final dataset. The overall summary C-statistic showed a mean of 0.71 across all models, indicating a reasonable level of predictiveness. A total of 15 articles (57%) were attributed to the spine, making it the most commonly explored orthopaedic field in our study. When comparing accuracy of prediction models between different fields, models predicting readmissions after hip/knee arthroplasty procedures had a higher prediction accuracy (mean C-statistic = 0.79) than spine (mean C-statistic = 0.7) and shoulder (mean C-statistic = 0.67). In addition, models that used single institution data, and those that included intraoperative and/or postoperative outcomes, had a higher mean C-statistic than those utilizing other data sources, and that include only preoperative predictors. According to the Prediction model Risk of Bias Assessment Tool, the majority of the articles in our study had a high risk of bias. CONCLUSION: AI tools perform reasonably well in predicting readmissions after orthopaedic procedures. Future work should focus on standardizing study methodologies and designs, and improving the data analysis process, in an attempt to produce more reliable and tangible results. LEVEL OF EVIDENCE: Level III. See Instructions for Authors for a complete description of levels of evidence.

Racial and gender disparities in utilization of outpatient total shoulder arthroplasties.

BACKGROUND: Utilization in outpatient total shoulder arthroplasties (TSAs) has increased significantly in recent years. It remains largely unknown whether utilization of outpatient TSA differs across gender and racial groups. This study aimed to quantify racial and gender disparities both nationally and by geographic regions. METHODS: 168,504 TSAs were identified using Medicare fee-for-service inpatient and outpatient claims data and beneficiary enrollment data from 2020 to 2022Q4. The percentage of outpatient cases, defined as cases discharged on the same day of surgery, was evaluated by racial and gender groups and by different census divisions. A multivariate logistics regression model controlling for patient sociodemographic information (White vs. non-White race, age, gender, and dual eligibility for both Medicare and Medicaid), hierarchical condition category (HCC) score, hospital characteristics, year fixed effects, and patient residency state fixed effects was performed. RESULTS: The TSA volume per 1000 beneficiaries was 2.3 for the White population compared with 0.8, 0.6, and 0.3 for the Black, Hispanic, and Asian population, respectively. A higher percentage of outpatient TSAs were in White patients (25.6%) compared with Black patients (20.4%) (P < .001). The Black TSA patients were also younger, more likely to be female, more likely to be dually eligible for Medicaid, and had higher HCC risk scores. After controlling for patient sociodemographic characteristics and hospital characteristics, the odds of receiving outpatient TSAs were 30% less for Black than the White group (odds ratio 0.70). Variations were observed across different census divisions, with South Atlantic (0.67, P < .01), East North Central (0.56, P < .001), and Middle Atlantic (0.36, P < .01) being the 4 regions observed with significant racial disparities. Statistically significant gender disparities were also found nationally and across regions, with an overall odds ratio of 0.75 (P < .001). DISCUSSION: Statistically significant racial and gender disparities were found nationally in outpatient TSAs, with Black patients having 30% (P < .001) fewer odds of receiving outpatient TSAs than White patients, and female patients with 25% (P < .001) fewer odds than male patients. Racial and gender disparities continue to be an issue for shoulder arthroplasties after the adoption of outpatient TSAs.

Diffusion MRI of the facial-vestibulocochlear nerve complex: a prospective clinical validation study.

OBJECTIVES: Surgical planning of vestibular schwannoma surgery would benefit greatly from a robust method of delineating the facial-vestibulocochlear nerve complex with respect to the tumour. This study aimed to optimise a multi-shell readout-segmented diffusion-weighted imaging (rs-DWI) protocol and develop a novel post-processing pipeline to delineate the facial-vestibulocochlear complex within the skull base region, evaluating its accuracy intraoperatively using neuronavigation and tracked electrophysiological recordings. METHODS: In a prospective study of five healthy volunteers and five patients who underwent vestibular schwannoma surgery, rs-DWI was performed and colour tissue maps (CTM) and probabilistic tractography of the cranial nerves were generated. In patients, the average symmetric surface distance (ASSD) and 95% Hausdorff distance (HD-95) were calculated with reference to the neuroradiologist-approved facial nerve segmentation. The accuracy of patient results was assessed intraoperatively using neuronavigation and tracked electrophysiological recordings. RESULTS: Using CTM alone, the facial-vestibulocochlear complex of healthy volunteer subjects was visualised on 9/10 sides. CTM were generated in all 5 patients with vestibular schwannoma enabling the facial nerve to be accurately identified preoperatively. The mean ASSD between the annotators' two segmentations was 1.11 mm (SD 0.40) and the mean HD-95 was 4.62 mm (SD 1.78). The median distance from the nerve segmentation to a positive stimulation point was 1.21 mm (IQR 0.81-3.27 mm) and 2.03 mm (IQR 0.99-3.84 mm) for the two annotators, respectively. CONCLUSIONS: rs-DWI may be used to acquire dMRI data of the cranial nerves within the posterior fossa. CLINICAL RELEVANCE STATEMENT: Readout-segmented diffusion-weighted imaging and colour tissue mapping provide 1-2 mm spatially accurate imaging of the facial-vestibulocochlear nerve complex, enabling accurate preoperative localisation of the facial nerve. This study evaluated the technique in 5 healthy volunteers and 5 patients with vestibular schwannoma. KEY POINTS: • Readout-segmented diffusion-weighted imaging (rs-DWI) with colour tissue mapping (CTM) visualised the facial-vestibulocochlear nerve complex on 9/10 sides in 5 healthy volunteer subjects. • Using rs-DWI and CTM, the facial nerve was visualised in all 5 patients with vestibular schwannoma and within 1.21-2.03 mm of the nerve's true intraoperative location. • Reproducible results were obtained on different scanners.

Arthroscopic Transosseous Rotator Cuff Repair.

Open transosseous rotator cuff repair (RCR) was the original benchmark surgical technique for RCR. The advent of arthroscopic and suture anchor technology shifted the paradigm from open to arthroscopic surgery. Although technological advances have progressed, they come at a cost. Suture anchor technology is expensive, optimal constructs have yet to be determined, and the technology may lead to challenging complications and revision scenarios. In more recent years, a return to transosseous bone tunnels has been described with new arthroscopic techniques, eliminating the need for suture anchors. The purpose of this article is to review the historical, biomechanical, clinical, and economic literature surrounding arthroscopic transosseous RCR.

Resection of Ependymomas Infiltrating the Fourth Ventricular Floor: Anatomosurgical and Stimulation Mapping Techniques.

BACKGROUND: Despite the importance of complete, gross total resection (GTR) of fourth ventricular ependymomas, significant morbidity and/or subtotal resections are reported, particularly when the ventricular floor is infiltrated. Step-by-step technique descriptions are lacking in the literature. OBJECTIVE: To describe monitoring and stimulation mapping techniques and surgical nuances in the challenging subgroup of infiltrating fourth ventricular ependymomas by a highly illustrated, step-by-step description. Superimposed outlines of cranial nerve nuclei on the surgical field demonstrate critical anatomy and facilitate understanding in a way not previously presented. METHODS: We reviewed the microanatomical and neurophysiological prerequisites of resecting a diffusively infiltrating fourth ventricular ependymoma. RESULTS: We achieved GTR with the use of reproducible stimulating mapping and accurate cranial nerve nuclei identification. CONCLUSION: Enhanced microanatomical understanding, reproducible stimulation mapping, and meticulous resection techniques can result in GTR, even in diffusively infiltrating ependymomas.

Intraoperative monitoring of visual evoked potentials in patients undergoing transsphenoidal surgery for pituitary adenoma: a systematic review.

BACKGROUND: Transsphenoidal surgery is the gold standard for pituitary adenoma resection. Although rare, a serious complication of surgery is worsened vision post-operatively. OBJECTIVE: To determine whether, in patients undergoing transsphenoidal surgery for pituitary adenoma, intraoperative monitoring of visual evoked potentials (VEP) is a safe, reproducible, and effective technological adjunct in predicting postoperative visual function. METHODS: The PubMed and OVID platforms were searched between January 1993 and December 2020 to identify publications that (1) featured patients undergoing transsphenoidal surgery for pituitary adenoma, (2) used intraoperative optic nerve monitoring with VEP and (3) reported on safety or effectiveness. Reference lists were cross-checked and expert opinion sought to identify further publications. RESULTS: Eleven studies were included comprising ten case series and one prospective cohort study. All employed techniques to improve reliability. No safety issues were reported. The only comparative study included described a statistically significant improvement in post-operative visual field testing when VEP monitoring was used. The remaining case-series varied in conclusion. In nine studies, surgical manipulation was halted in the event of a VEP amplitude decrease suggesting a widespread consensus that this is a warning sign of injury to the anterior optic apparatus. CONCLUSIONS: Despite limited and low-quality published evidence regarding intra-operative VEP monitoring, our review suggests that it is a safe, reproducible, and increasingly effective technique of predicting postoperative visual deficits. Further studies specific to transsphenoidal surgery are required to determine its utility in protecting visual function in the resection of complex pituitary tumours.

True Transosseous Hybrid Rotator Cuff Repair.

Transosseous repair has been used safely and effectively for primary and revision rotator cuff repair for decades; as a result, it is considered by many the historical gold standard of open repair techniques. Transosseous repair offers the advantage of excellent biology, double-row anatomic footprint reconstruction, and the ability to create multiple low-cost fixation points per surface area of tendon with high-strength suture, while avoiding anchor pullout, cyst formation, and imaging artifact. More recently, in arthroscopic applications, transosseous-equivalent anchor-based repairs have been introduced that have shown satisfactory clinical and biomechanical results; however, these attributes have been coupled with increased cost, nonbiologic burden to the healing interface of the tendon, and new catastrophic failure modes including tendon transection, anchor pullout, and bone voids. This article delineates a technique for arthroscopic true transosseous hybrid cuff repair that combines the use of anchors and transosseous techniques to maximize the benefits and minimize the detriments of both techniques. Level 1 (shoulder); level 2 (rotator cuff).

Clinical success of biceps tenodesis with and without release of the transverse humeral ligament.

BACKGROUND: Multiple methods for biceps tenodesis exist, but long-term studies have demonstrated high failure rates. We hypothesized that tenodesis techniques that do not release the biceps sheath are associated with a higher surgical revision rate than those that do. METHODS: A retrospective study was conducted of 127 biceps surgeries over a 2-year period. The mean follow-up post surgery was 22 months (range, 6-59). Clinical failure was defined as ongoing pain localized in the biceps groove, severe enough to warrant revision surgery. RESULTS: When all techniques that released the biceps sheath (6.8%, 4/59) were compared to those that did not release the biceps sheath (20.6%, 14/68), a statistically significant difference was found, P = .026 (chi-square). Proximal arthroscopic techniques were revised at a significantly higher rate than distal tenodesis techniques (P = .005). CONCLUSION: Biceps tenodesis techniques which do not release the biceps sheath or remove the tendon from the sheath have increased revision rates, compared to techniques that do. This may be supportive evidence for the theory that residual pain generating elements in the biceps groove is a cause of failure of proximal tenodesis methods.

Treatment of a symptomatic forearm muscle herniation with a mesh graft.

Symptomatic muscle herniations are an unusual cause of upper extremity pain in the athlete that is rarely reported in the literature. Out of 18 reported cases of upper extremity herniations, only 3 were caused by strenuous exertion. This article describes a successful repair of a 21-year-old rock climber's ventral forearm herniation with polypropylene mesh.

Heterotopic ossification of the deltoid muscle after arthroscopic rotator cuff repair.

Heterotopic ossification (HO), a well-known sequela of trauma, burns, head injury, and certain congenital or acquired metabolic conditions, has a predilection for the hip and the elbow. This disease has uncommonly been found after elective open shoulder surgery but extremely seldom after minimally invasive surgery. In our search of the peer-reviewed literature, we found no reports of HO after arthroscopic rotator cuff repair. The clinical importance of heterotopic bone after shoulder surgery remains unclear because of inconsistent definitions, varying correlations of symptom severity and radiographic findings, and lack of treatment efficacy data. Here we report a case of severely symptomatic HO after arthroscopic rotator cuff repair - successfully treated with excision of the heterotopic bone, interval release, and manipulation.

Acromioclavicular joint injuries: diagnosis and management.

Acromioclavicular joint injuries represent nearly half of all athletic shoulder injuries, often resulting from a fall onto the tip of the shoulder with the arm in adduction. Stability of this joint depends on the integrity of the acromioclavicular ligaments and capsule as well as the coracoclavicular ligaments and the trapezius and deltoid muscles. Along with clinical examination for tenderness and instability, radiographic examination is critical in the evaluation of acromioclavicular joint injuries. Nonsurgical treatment is indicated for type I and II injuries; surgery is almost always recommended for type IV, V, and VI injuries. Management of type III injuries remains controversial, with nonsurgical treatment favored in most instances and reconstruction of the acromioclavicular joint reserved for symptomatic instability. Recommended techniques for stabilization in cases of acute and late symptomatic instability include screw fixation of the coracoid process to the clavicle, coracoacromial ligament transfer, and coracoclavicular ligament reconstruction. Biomechanical studies have demonstrated that anatomic acromioclavicular joint reconstruction is the most effective treatment for persistent instability.

Prevalence of saphenous nerve injury after autogenous hamstring harvest: an anatomic and clinical study of sartorial branch injury.

PURPOSE: Injury to the sartorial (terminal) branch of the saphenous nerve (SBSN) has received little attention in the literature, despite its anatomic proximity to the hamstring tendons during autogenous harvesting. This study aims to define the prevalence of saphenous nerve injury after anterior cruciate ligament (ACL) reconstruction with autogenous hamstrings and define clinically relevant anatomy that may contribute to nerve injury. METHODS: Surveys regarding the presence and duration of sensory changes in the infrapatellar branch of the saphenous nerve (IPBSN) and SBSN were retrospectively sent to 164 patients who had undergone arthroscopically assisted ACL reconstruction with hamstring autograft over a 4-year period. Eleven cadavers were then dissected to identify the relation of the saphenous nerve to the hamstring tendons and accessory insertions. RESULTS: Postoperative sensory disturbance was present in 74% of patients surveyed. Concomitant injuries to both the SBSN and IPBSN occurred in 32% of patients, whereas isolated paresthesias in the SBSN and IPBSN distribution affected 23% and 19%, respectively. The saphenous nerve was intimately associated with the gracilis for 4.6 cm in the distal thigh, from 7.2 cm (range, 6.4 to 9.3 cm) to 11.8 cm (range, 7 to 13.2 cm) proximal to its insertion. Accessory hamstring insertions were present distal to the point where the sartorial branch became extrafascial. CONCLUSIONS: The SBSN is at higher risk of injury during hamstring ACL reconstruction than has been previously reported. The saphenous nerve is intimately involved with the gracilis tendon for a portion of its course in the distal thigh, likely predisposing it to damage during passage of the tendon stripper. LEVEL OF EVIDENCE: Level IV.

Biomechanical evaluation of locked plating in proximal humeral fractures.

The ideal method of fixation in proximal humeral fractures is not well established. Locked plating is a potential solution, but to date, there has been little support shown in the literature. We compared the biomechanical performance of a locked plate with that of an intramedullary humeral nail in a cadaveric model. Paired fresh-frozen cadaveric humeri (N = 5) were instrumented with either a locked plate or an intramedullary nail after creation of a 3-part osteotomy. Construct stiffness, cyclic loading behavior, and load to failure were evaluated. The locked plate was more stiff in valgus loading than the nail (P = .003). All other loading vectors showed no statistical differences in stiffness between the two constructs. The load to failure was 828 N for the plate and 901 N for the nail. The nail showed interfragmentary motion (degrees), or toggle, at zero load, whereas the plate did not. The locked plate, being stable at zero load, may prove useful in earlier pain-free rehabilitation of proximal humeral fractures.