Developing a Computer Vision Model to Automate Quantitative Measurement of Hip-Knee-Ankle Angle in Total Hip and Knee Arthroplasty Patients.

BACKGROUND: Increasing deformity of the lower extremities, as measured by the hip-knee-ankle angle (HKAA), is associated with poor patient outcomes after total hip and knee arthroplasty (THA, TKA). Automated calculation of HKAA is imperative to reduce the burden on orthopaedic surgeons. We proposed a detection-based deep learning (DL) model to calculate HKAA in THA and TKA patients and assessed the agreement between DL-derived HKAAs and manual measurement. METHODS: We retrospectively identified 1,379 long-leg radiographs (LLRs) from patients scheduled for THA or TKA within an academic medical center. There were 1,221 LLRs used to develop the model (randomly split into 70% training, 20% validation, and 10% held-out test sets); 158 LLRs were considered "difficult," as the femoral head was difficult to distinguish from surrounding tissue. There were 2 raters who annotated the HKAA of both lower extremities, and inter-rater reliability was calculated to compare the DL-derived HKAAs with manual measurement within the test set. RESULTS: The DL model achieved a mean average precision of 0.985 on the test set. The average HKAA of the operative leg was 173.05 ± 4.54°; the nonoperative leg was 175.55 ± 3.56°. The inter-rater reliability between manual and DL-derived HKAA measurements on the operative leg and nonoperative leg indicated excellent reliability (intraclass correlation (2,k) = 0.987 [0.96, 0.99], intraclass correlation (2, k) = 0.987 [0.98, 0.99, respectively]). The standard error of measurement for the DL-derived HKAA for the operative and nonoperative legs was 0.515° and 0.403°, respectively. CONCLUSIONS: A detection-based DL algorithm can calculate the HKAA in LLRs and is comparable to that calculated by manual measurement. The algorithm can detect the bilateral femoral head, knee, and ankle joints with high precision, even in patients where the femoral head is difficult to visualize.

Utility of Patient Reported Outcome Measurement Information System measures in predicting shoulder arthroplasty in patients with shoulder osteoarthritis.

BACKGROUND: The decision to treat shoulder osteoarthritis (OA) definitively with shoulder arthroplasty (SA) is multifactorial, considering objective findings, subjective information, and patient goals. The first goal of this study was to determine if Patient Reported Outcome Measurement Information System (PROMIS) measures correlated with patients with shoulder OA who underwent SA within 1 year. The second goal of this study was to determine if score cut-offs in PROMIS domains could further discriminate which shoulder OA patients underwent SA within 1 year. METHODS: This retrospective case-control study examined patients with a diagnosis of shoulder OA who consulted an orthopedic provider from November 1, 2020 to May 23, 2022, and recorded PROMIS measures in the domains of Physical Function, Depression, and/or Pain Interference. A surgical group was defined as patients who underwent SA within 1 year of the most recent PROMIS measures and the nonsurgical patients were defined as the control group. Mean PROMIS scores were compared between the surgical and control groups. Separate logistic regression models controlling for age, race, ethnicity, and comorbidity count were performed for each PROMIS domain as a 1) continuous variable, and then as 2) binary variable defined by PROMIS score cut-off points to determine which scores correlated with undergoing SA to further characterize the potential clinical utility of PROMIS score cut-offs in relating to undergoing SA. RESULTS: The surgical group of 478 patients was older (68.2 vs. 63.8 years), more often of White race (82.6% vs. 70.9%), and less often of Hispanic Ethnicity (1.5% vs. 2.9%) than the control group of 3343 patients. Using optimal cut-offs in PROMIS scores, Pain Interference ≥63 (odds ratio [OR] = 2.97 (2.41-3.64), P < .001), Physical Function ≤39 (OR = 1.81 (95% confidence interval, 1.48-2.22), P < .001), and depression ≥49 (OR = 1.82 (95% confidence interval, 1.50-2.22), P < .001) were all found to correlate with undergoing SA within 1 year in multivariable logistic regressions. CONCLUSION: The results of this study demonstrate that cut-off scores for PROMIS measures differentiated patients undergoing SA within 1 year. These cut-off scores may have clinical utility in aiding in decision-making regarding surgical candidates for SA. Further research is needed to validate these cut-off scores and determine how they relate to patient outcomes after SA.

Does Medically Supervised Weight Loss Prior to Total Knee Arthroplasty Improve Patient-Reported Pain and Physical Function?

BACKGROUND: Weight loss is commonly recommended before total knee arthroplasty (TKA) despite inconsistent evidence for better outcomes. This study sought to examine the impacts of preoperative weight loss on patient-reported and adverse outcomes among TKA patients supervised by a medical weight management clinic. METHODS: This study retrospectively analyzed patients who underwent medical weight management supervision within 18 months before TKA comparing patients who did and did not have clinically relevant weight loss. Preoperative body mass indices, demographics, Patient-Reported Outcomes Measurement Information System physical function and pain interference scores, pain intensity scores, and adverse outcomes were extracted. Multivariable linear regressions were performed to determine if preoperative weight loss correlated with patient-reported outcomes after controlling for confounders. RESULTS: There were 90 patients, 75.6% women, who had a mean age of 65 years (range, 42-82) and were analyzed. There were 51 (56.7%) patients who underwent clinically relevant weight loss with a mean weight loss of 10.4% and experienced no difference in adverse outcomes. Preoperative weight loss predicted significantly improved 3-month postoperative physical function (ß = 15.2 [13.0-17.3], P < .001), but not pain interference (ß = -18.9 [-57.1-19.4], P = .215) or pain intensity (ß = -1.8 [-4.9-1.2], P = .222) scores. CONCLUSION: We found that medically supervised preoperative weight loss predicted improvement in physical function 3 months after TKA. This weight loss caused no major adverse effects. Further research is needed to understand the causal relationships between preoperative weight loss, medical supervision, and outcome after TKA and to elucidate potential longer-term benefits in a larger sample.

Outcome Disparities in Total Knee and Total Hip Arthroplasty among Native American Populations.

BACKGROUND: No prior racial disparities studies in total knee arthroplasty (TKA) and total hip arthroplasty (THA) have specifically evaluated outcomes among American Indian or Alaska Native (AIAN) patients. We hypothesized that AIAN patients have worse outcomes than White patients after controlling for demographics and comorbidities. METHODS: This was a retrospective cohort study comparing White and AIAN patients undergoing primary TKA/THA from 2012-2019 using the American College of Surgeons National Surgical Quality Improvement Program. Race, demographics, and comorbidities were analyzed for correlations with 30-day outcomes and complications using multivariable logistic and linear regression analyses. RESULTS: Comparing 422,215 White and 2,676 AIAN patients, AIAN patients had higher American Society of Anesthesiologist (ASA) classifications, body mass index (BMI), and were younger at the time of surgery. AIAN patients more often stayed inpatient > 2 days (49.4% vs 36.2%, p < 0.001), underwent reoperation (2.1% vs 1.4%, p < 0.01), and were discharged home (91.4% vs 81.7%, p < 0.01). Regression analyses controlling for age, BMI, sex, ASA classification, and functional status found that AIAN race was significantly positively correlated with a length of stay > 2 days (OR 1.6), reoperation (OR 1.4), and discharging home (OR 2.0). CONCLUSION: AIAN patients undergoing TKA/THA present with a greater comorbidity burden compared to White patients and experience multiple worse outcome metrics including increased hospital length of stay and reoperation rates. Interestingly, AIAN patients were more likely to discharge home, representing a unique racial disparity which warrants further study.

Radiographic comparison of eccentric stemmed vs. concentric stemless prosthetic humeral head positioning after anatomic total shoulder arthroplasty.

INTRODUCTION: Maintaining premorbid proximal humeral positioning is an essential consideration of anatomic total shoulder arthroplasty (aTSA), as malposition of the prosthetic humeral head can result in poor clinical outcomes. Stemless aTSA prosthetic heads are usually concentric, while stemmed aTSA prosthetic heads are typically eccentric in nature. Therefore, the purpose of this study was to compare the ability to restore native humeral head position between stemmed (eccentric) vs. stemless (concentric) aTSA. MATERIALS AND METHODS: Postoperative anteroposterior radiographs of 52 stemmed and 46 stemless aTSAs were analyzed. A best-fit circle was created using previously published and validated techniques to represent the premorbid humeral head position and axis of rotation. This circle was juxtaposed with another circle following the arc of the implant head. Next, the offset in center of rotation (COR), radius of curvature (RoC), and humeral head height above the greater tuberosity (HHH) were measured. Additionally, based on prior studies, an offset of >3 mm at any point between the implant head surface and premorbid best-fit circle was considered significant and further classified as overstuffed or understuffed. RESULTS: RoC deviation was significantly greater in the stemmed cohort than the stemless cohort (1.19 ± 1.37 mm vs. 0.65 ± 1.17 mm, P = .025). There was no statistically significant difference in deviation from premorbid humeral head between the stemmed and stemless cohorts for COR (3.20 ± 2.28 mm vs. 3.23 ± 2.09 mm, P = .800) or HHH (1.12 ± 3.27 mm vs. 0.92 ± 2.70 mm, P = .677). When comparing overstuffed implants to appropriately placed implants, there was a significant difference in overall COR deviation in stemmed implants (3.93 ± 2.51 mm vs. 1.92 ± 1.05 mm, P < .001). Superoinferior COR deviation (stemmed: 2.38 ± 3.01 mm vs. -0.61 ± 1.59 mm, P < .001; stemless: 2.70 ± 1.75 mm vs. -0.16 ± 1.87 mm, P < .001), mediolateral COR deviation (stemmed: 0.79 ± 2.65 mm vs. -0.62 ± 1.27 mm, P = .020; stemless: 0.40 ± 1.41 mm vs. -1.13 ± 1.96 mm, P = .020), and HHH (stemmed: 3.61 ± 2.73 mm vs. 0.50 ± 1.31 mm, P < .001; stemless: 3.98 ± 1.18 mm vs. 0.53 ± 1.41 mm, P < .001) were significantly different between overstuffed implants and appropriate implants in both the stemmed and stemless cohorts. DISCUSSION: Stemless and stemmed aTSA implants have similar rates of reproducing satisfactory postoperative humeral head COR with both producing COR deviation most commonly in the superomedial direction. Deviation in HHH contributes to overstuffing in both stemmed and stemless implants, COR deviation contributes to overstuffing in stemmed implants, while RoC (humeral head size) is not associated with overstuffing. Based on this study, it appears that neither eccentric nor concentric prosthetic heads are superior in recreating premorbid humeral head position.

Does Preoperative Weight Loss Within 6 Months or 1 Year Change the Risk of Adverse Outcomes in Total Knee Arthroplasty by Initial Body Mass Index Classification?

BACKGROUND: High body mass index (BMI) is associated with adverse outcomes after total knee arthroplasty (TKA). Thus, many patients are advised to lose weight before TKA. This study examined how weight loss before TKA is associated with adverse outcomes depending on patients' initial BMI. METHODS: This was a retrospective study of 2,110 primary TKAs at a single academic center. Data on preoperative BMIs, demographics, comorbidities, and incidences of revision or prosthetic joint infection (PJI) were obtained. Multivariable logistic regressions segmented by patients' initial (1-year preoperative) BMI classifications were performed to determine if a > 5% BMI decrease from 1 year or 6 months preoperatively predicted PJI and revision controlling for patient age, race, sex, and Elixhauser comorbidity index. RESULTS: Preoperative weight loss did not predict adverse outcomes for patients who had Obesity Class II or III. 6-month weight loss had greater odds of adverse outcomes than 1-year weight loss and most significantly predicted the occurrence of 1-year PJI (adjusted odds ratio: 6.55, P < .001) for patients who had Obesity Class 1 or lower. CONCLUSION: This study does not show a statistically significant effect to patients who had Obesity Class II and III losing weight preoperatively with respect to PJI or revision. For patients who have Obesity Class I or lower pursuing TKA, future research should consider potential risks associated with weight loss. Further study is needed to determine if weight loss can be implemented as a safe and effective risk reduction strategy for specific BMI classes of TKA patients.

Interfragmentary strain measurement post-fixation to guide intraoperative decision making: a narrative review.

PURPOSE: Interfragmentary strain influences whether a fracture will undergo direct and indirect fracture healing. Orthopedic trauma surgeons modulate strain and create optimal biomechanical environments for specific fracture patterns using fixation constructs. However, objective intraoperative interfragmentary strain measurement does not currently inform fixation strategy in common practice. This review identifies potential methods and technologies to enable intraoperative strain measurement for guiding optimal fracture fixation strategies. METHODS: PubMed, Scopus, and Web of Science were methodologically queried for manuscripts containing terms related to "bone fracture," "strain," "measurement," and "intraoperative." Manuscripts were systematically screened for relevance and adjudicated by three reviewers. Relevant articles describing methods to measure interfragmentary strain intraoperatively were summarized. RESULTS: After removing duplicates, 1404 records were screened initially. There were 49 manuscripts meeting criteria for in-depth review. Of these, four reports were included in this study that described methods applicable to measuring interfragmentary strain intraoperatively. Two of these reports described a method using instrumented staples, one described optical tracking of Kirschner wires, and one described using a digital linear variable displacement transducer with a custom external fixator. CONCLUSION: The four reports identified by this review describe potential methods to quantify interfragmentary strain after fixation. However, further studies are needed to confirm the precision and accuracy of these measurements across a range of fractures and fixation methods. Additionally, described methods require the insertion and likely removal of additional implants into the bone. Ideally, innovations that measure interfragmentary strain intraoperatively would provide dynamic biomechanical feedback for the surgeon to proactively modulate construct stability.

Concordance of Preoperative 3D Templating in Stemless Anatomic Total Shoulder Arthroplasty.

INTRODUCTION: Recent advances in preoperative 3D templating software allow surgeons to plan implant size and position for stemless total shoulder arthroplasty (TSA). Whether these preoperative plans accurately reflect intraoperative decisions is yet unknown, and the purpose of this study was to evaluate concordance between planned and actual implant sizes in a series of patients undergoing stemless TSA. METHODS: A retrospective cohort of consecutive, anatomic, stemless TSA cases performed by two surgeons between September 2019 and February 2021 was examined. Preoperative templated plans were collected using 3D planning software, and the sizes of planned glenoid, humeral head, and nucleus "stem" implants and other procedural data were recorded, along with sociodemographic information. These predicted parameters were compared with the implant sizes, and the concordance of these templated plans was quantified by direct comparison and bootstrapped simulations. RESULTS: Fifty cases met inclusion criteria, among which perfect concordance across all three implants was observed in 11 cases (22%). The glenoid implant had the highest concordance (80%) relative to the humeral head and nucleus implants (38% and 60%, respectively), which was statistically significant ( P < 0.001). Planned humeral head implants were more often oversized relative to their actual implanted size. However, 84% of the planned humeral heads were within 1 diameter size; in addition, 98% of the planned glenoid implants were within one size and all were within 10 mm of the implanted glenoid backside radius. All nucleus implants were within one size. DISCUSSION: Final implant sizes demonstrated variable concordance relative to preoperative plans, with glenoid implants having the highest accuracy and humeral heads having the highest variability. Multiple factors contributed to the varying concordances for the different implants, suggesting possible areas of improvement in this technology. These results may have implications for logistics, intraoperative efficiency, and overall cost and underscore the potential value of this technology. LEVEL OF EVIDENCE: Level III.

Simple preoperative radiographic and computed tomography measurements predict adequate bone quality for stemless total shoulder arthroplasty.

INTRODUCTION: Although there is increased utilization of stemless humeral implants in anatomic total shoulder arthroplasty (TSA), there are inadequate objective metrics to evaluate bone quality sufficient for fixation. Our goals are to: (1) compare patient characteristics in patients who had plans for stemless TSA but received stemmed TSA due to intraoperative assessments and (2) propose threshold values of bone density, using the deltoid tuberosity index (DTI) and proximal humerus Hounsfield units (HU), on preoperative X-ray and computed tomography (CT) to allow for preoperative determination of adequate bone stock for stemless TSA. METHODS: This is an observational study conducted at an academic institution from 2019 to 2021, including consecutive primary TSAs templated to undergo stemless TSA based on 3-dimensional CT preoperative plans. Final implant selection was determined by intraoperative assessment of bone quality. Preoperative X-ray and CT images were assessed to obtain DTI and proximal humeral bone density in HU, respectively. A receiver operating characteristic curve was used to analyze the potential of preoperative X-ray and CT to classify patients as candidates for stemless TSA. RESULTS: A total of 61 planned stemless TSAs were included, with 56 (91.8%) undergoing stemless TSA and 5 (8.2%) undergoing stemmed TSA after intraoperative assessment determined that the bone quality was inadequate for stemless fixation. There were no significant differences between the 2 groups in terms of gender (P = .640), body mass index (P = .296), and race (P = .580). The stem cohort was significantly older (mean age 69 ± 12 years vs. 59 ± 10 years, P = .029), had significantly lower DTI (1.45 ± 0.13 vs. 1.68 ± 0.18, P = .007), and had significantly less proximal humeral HU (-1.4 ± 17.7 vs. 78.8 ± 52.4, P = .001). The receiver operating characteristic curve for DTI had an area under the curve (AUC) of 0.86, and bone density in HU had an AUC of 0.98 in its ability to distinguish patients who underwent stemless TSA vs. short-stem TSA. A threshold cutoff of 1.41 for DTI resulted in a sensitivity of 98% and a specificity of 60%, and a cutoff value of 14.4 HU resulted in a sensitivity of 95% and a specificity of 100%. CONCLUSIONS: Older age, lower DTI, and less proximal humeral bone density in HU were associated with the requirement to switch from stemless to short-stem humeral fixation in primary TSA. Preoperative DTI had good ability (AUC of 0.86) and preoperative HU had excellent ability (AUC of 0.98) to categorize patients as appropriate for stemless TSA. This can help surgeons adequately plan humeral fixation using standard preoperative imaging data.