Mixed-reality improves execution of templated glenoid component positioning in shoulder arthroplasty: a CT imaging analysis.

INTRODUCTION: Glenoid placement is critical for successful outcomes in total shoulder arthroplasty (TSA). Preoperative templating with three-dimensional imaging has improved implant positioning, but deviations from the planned inclination and version still occur. Mixed-Reality (MR) is a novel technology that allows surgeons intra-operative access to three-dimensional imaging and templates, capable of overlaying the surgical field to help guide component positioning. The purpose of this study was to compare the execution of preoperative templates using MR vs.standard instruments (SIs). METHODS: Retrospective review of 97 total shoulder arthroplasties (18 anatomic, 79 reverse) from a single high-volume shoulder surgeon between January 2021 and February 2023, including only primary diagnoses of osteoarthritis, rotator cuff arthropathy, or a massive irreparable rotator cuff tear. To be included, patients needed a templated preoperative plan and then a postoperative computed tomography scan. Allocation to MR vs. SI was based on availability of the MR headset, industry technical personnel, and the templated preoperative plan loaded into the software, but preoperative or intraoperative patient factors did not contribute to the allocation decision. Postoperative inclination and version were measured by two independent, blinded physicians and compared to the preoperative template. From these measurements, we calculated the mean difference, standard deviation (SD), and variance to compare MR and SI. RESULTS: Comparing 25 MR to 72 SI cases, MR significantly improved both inclination (P < .001) and version (P < .001). Specifically, MR improved the mean difference from preoperative templates (by 1.9° inclination, 2.4° version), narrowed the SD (by 1.7° inclination, 1.8° version), and decreased the variance (11.7-3.0 inclination, 14.9-4.3 version). A scatterplot of the data demonstrates a concentration of MR cases within 5° of plan relative to SI cases typically within 10° of plan. There was no difference in operative time. CONCLUSION: MR improved the accuracy and precision of glenoid positioning. Although it is unlikely that 2° makes a detectable clinical difference, our results demonstrate the potential ability for technology like MR to narrow the bell curve and decrease the outliers in glenoid placement. This will be particularly relevant as MR and other similar technologies continue to evolve into more effective methods in guiding surgical execution.

Radius of curvature of the radial head matches the capitellum: a magnetic resonance imaging analysis.

Background: The purpose of this study is to utilize elbow magnetic resonance imaging (MRI) to compare the radius of curvature (ROC) of the radial head peripheral cartilaginous rim and the cartilage contour of the capitellum to evaluate if the radial head could be a suitable osteochondral autograft for capitellar pathology. Methods: All patients who underwent an MRI of the elbow over a three-year period were reviewed. Patients with the following diagnoses were excluded: osteochondritis dissecans, osteomyelitis, tumor, and osteoarthritis. The radius of curvature of the radial head (RhROC) was measured on the axial oblique MRI sequence. The radius of curvature of the capitellum (CapROC) was measured on sagittal oblique MRI sequences, the width of the articular surface of the capitellum on coronal MRI sequences and the radial head height (RhH) and capitellar vertical height on sagittal oblique sequences. All measurements were obtained at the midpoint of the radiocapitellar joint. Spearman's coefficient was used to assess the correlation between ROC measurements. Results: Eighty-three patients were included with a mean age of 43 +/- 17 years (57 males and 26 females, 51 right and 32 left elbows). The median RhROC and CapROC measurements were 12.3 mm (interquartile range [IQR] 1.6) and 11.9 mm (IQR 1.7), respectively. The median difference was 0.3 mm (IQR = 0.6; CI 95% = [0.24, 0.46]; P < .001). A strong positive correlation was found between RhROC and CapROC (ρ = 0.89; r2 = 0.819; P < .001). Ninety-four percent (78/83) of patients had a median difference between the RhROC and CapROC of less than or equal to 1 mm, and 63% (52/83) were within 0.5 mm. The inter-rater and intra-rater reliability for RhROC and CapROC was good, intraclass correlation coefficient (ICC) = 0.89, ICC = 0.87, and ICC = 0.96, ICC = 0.97, respectively. RhH was 10.6 ± 1.3 mm, and the width of the articular surface of the capitellum was found to be 13.8 ± 1.6 mm. Conclusion: The ROC of the convex peripheral cartilaginous rim of the radial head is similar to the ROC of the capitellum. In addition, the RhH was approximately 78% of the capitellar articular width. Based on this imaging analysis, the radial head could prove to be a robust local osteochondral autograft with a similar cartilage contour in the reconstruction of the capitellum in complex intra-articular distal humerus fractures with associated radial head fractures and in the setting of "kissing lesions" of the radiocapitellar joint. Furthermore, an osteochondral plug harvested from the "safe zone" of the peripheral cartilaginous rim of the radial head could be utilized to treat isolated osteochondral lesions of the capitellum.

Short-term outcomes after primary reverse total shoulder arthroplasty in patients with cervical spine pathology or previous cervical spine surgery compared to those without.

BACKGROUND: Cervical spine (c-spine) and shoulder pathology have been known to cause similar symptoms and often co-exist, making an accurate diagnosis difficult, especially in an elderly population. Reverse total shoulder arthroplasty (rTSA) has been shown to decrease pain and improve quality of life when shoulder pathology is the source of pain and disability. The purpose of this study was to identify the prevalence of c-spine pathology in a cohort of patients who underwent rTSA and to compare postoperative outcome scores to a cohort without c-spine pathology. METHODS: A retrospective review was performed utilizing a single institution's operative records of primary rTSAs. Radiology reports, imaging, and operative reports were reviewed, and presence of any c-spine pathology or previous surgery were recorded. Additionally, postoperative outcome scores (American Shoulder and Elbow Surgeons [ASES], Constant Score, University of California, Los Angeles [UCLA], and Simple Shoulder Test [SST]) were evaluated at >2 years post-rTSA. RESULTS: A total of 438 primary rTSA cases were evaluated. Of these, 143 (32.6%) had documentation of prior c-spine pathology and/or history of previous c-spine surgery. After applying further exclusion criteria, a total of 50 patients with c-spine pathology and 108 patients without c-spine pathology were found to have complete medical records and postoperative outcome scores to allow comparison between groups. Patients without c-spine pathology were found to have statistically higher postoperative UCLA, ASES, and SST scores when compared to patients with c-spine pathology. Patients without c-spine pathology also demonstrated a significant improvement in the difference between their postoperative and preoperative UCLA and ASES scores. CONCLUSION: This study demonstrated a high prevalence of c-spine pathology (32.6%) in a cohort of patients who underwent primary rTSA. Additionally, short-term outcome scores of patients undergoing rTSA with concomitant c-spine pathology are significantly lower than those of patients without a history of c-spine pathology.

Utility of Allograft Talus as a Source for Grafting of Concurrent Humeral and Glenoid Defects Associated With Anterior Glenohumeral Instability: An Anthropometric Analysis.

PURPOSE: To compare morphologic data of the talus using magnetic resonance images with previously reported values of the humeral head and the glenoid as a potential graft source for both the humeral head as well as glenoid reconstruction in the setting of concomitant glenoid and humeral head defects. METHODS: All magnetic resonance images of the ankle were reviewed for assessment of the morphology and variation of the talus among individuals. Patients with post-traumatic, osteoarthritic, or surgical changes to the distal tibia about the mid- or hind- foot, or patients with incomplete medical records were excluded. Radiographic parameters that were measured included the maximum vertical height (MVH), the height to the talar neck, the radius of curvature (ROC) of the talar dome, ROC of the subtalar joint, and the maximum medial-to-lateral width of the talar dome. Demographic data also were collected on each individual. Statistical analysis was performed via a linear regression model with backwards elimination to determine which demographic data correlated most strongly with talar anthropometric values. RESULTS: A total of 82 study patients met inclusion criteria (59 male, 23 female; mean age 40.91 ± 14.69 years). Sex was found have a positive correlation of the following talar dimensions: MVH (P = .039), talar dome ROC (P < .001), and subtalar joint ROC (p = 0.001). Height was the most positive correlation for medial-to-lateral width (P < .001), height to the talar neck (P = .004), and also correlate for MVH (P = .004). Body mass index was found to have multicollinearity and was therefore not used as a variable. CONCLUSIONS: Allograft talus appears to be a viable graft, as demonstrated in this anthropometric study for both reconstruction of the glenoid and humeral head when cases of bipolar glenohumeral bone loss are present. CLINICAL RELEVANCE: This study aims to further evaluate potential allograft donor sites for bipolar lesions.

Guided growth for the Treatment of Infantile Blount's disease: Is it a viable option?

INTRODUCTION: Guided growth with temporary hemiepiphysiodesis has gained interest as a less invasive means for the treatment of coronal plane lower extremity deformities as well as leg length discrepancies. Its application to infantile Blount's disease has been less reported. The object of this study was to identify predictive factors of guided growth for treatment of infantile Blount's. METHODS: A retrospective review was performed of children undergoing guided growth for the treatment of infantile Blount's disease over an eight-year period. Inclusion criteria included treatment with THE for infantile Blount's disease. Clinical information, preoperative Langenskiold classification, and intra-operative and post-operative data. Preoperative variables were used to identify risk factors for speed of correction and the need for subsequent surgery. RESULTS: A total of 11 patients, 17 extremities, meeting inclusionary criteria. Preoperatively, 7 extremities were classified as Langenskiold stage ≥3, with 12 being classified as stage ≤2. Overall, the Drennan's angle improved from 18.3° to 0.3° by final follow-up at an average of 4.31 years. Eight extremities demonstrated deformity recurrence/persistence (stage ≤2:33% vs stage ≥3: 100%), requiring 24 reoperations. Children with Langenskiold stage ≥3 demonstrated a significantly higher rate of reoperation. CONCLUSION: Guided growth is a viable treatment option for Infantile Blount's disease presenting with Langenskiold stage ≤2 disease at treatment initiation. The treatment course can expect a 33% rate of recurrent deformity, treated successfully with repeat THE. No child stage ≤2 required corrective osteotomy. Caution should be used when considering guided growth for children presenting with Langenskiold stage ≥3.