Predicting Recovery Following Total Hip and Knee Arthroplasty Using a Clustering Algorithm.

Background: Recovery following total joint arthroplasty is patient-specific, yet groups of patients tend to fall into certain similar patterns of recovery. The purpose of this study was to identify and characterize recovery patterns following total hip arthroplasty (THA) and total knee arthroplasty (TKA) using patient-reported outcomes that represent distinct health domains. We hypothesized that recovery patterns could be defined and predicted using preoperative data. Methods: Adult patients were recruited from a large, urban academic center. To model postoperative responses to THA and TKA across domains such as physical health, mental health, and joint-specific measures, we employed a longitudinal clustering algorithm that incorporates each of these health domains. The clustering algorithm from multiple health domains allows the ability to define distinct recovery trajectories, which could then be predicted from preoperative and perioperative factors using a multinomial regression. Results: Four hundred forty-one of 1134 patients undergoing THA and 346 of 921 undergoing TKA met eligibility criteria and were used to define distinct patterns of recovery. The clustering algorithm was optimized for 3 distinct patterns of recovery that were observed in THA and TKA patients. Patients recovering from THA were divided into 3 groups: standard responders (50.8%), late mental responders (13.2%), and substandard responders (36.1%). Multivariable, multinomial regression suggested that these 3 groups had defined characteristics. Late mental responders tended to be obese (P = .05) and use more opioids (P = .01). Substandard responders had a larger number of comorbidities (P = .02) and used more opioids (P = .001). Patients recovering from TKA were divided among standard responders (55.8%), poor mental responders (24%), and poor physical responders (20.2%). Poor mental responders were more likely to be female (P = .04) and American Society of Anesthesiologists class III/IV (P = .004). Poor physical responders were more likely to be female (P = .03), younger (P = .04), American Society of Anesthesiologists III/IV (P = .04), use more opioids (P = .02), and be discharged to a nursing facility (P = .001). The THA and TKA models demonstrated areas under the curve of 0.67 and 0.72. Conclusions: This multidomain, longitudinal clustering analysis defines 3 distinct patterns in the recovery of THA and TKA patients, with most patients in both cohorts experiencing robust improvement, while others had equally well defined yet less optimal recovery trajectories that were either delayed in recovery or failed to achieve a desired outcome. Patients in the delayed recovery and poor outcome groups were slightly different between THA and TKA. These groups of patients with similar recovery patterns were defined by patient characteristics that include potentially modifiable comorbid factors. This research suggests that there are multiple defined recovery trajectories after THA and TKA, which provides a new perspective on THA and TKA recovery. Level of Evidence: III.

Interobserver and Intraobserver Reliability of Classification Systems for Radiographic Complications After Radial Head Arthroplasty.

PURPOSE: Although several classifications are used to assess radiographs following radial head arthroplasty (RHA), including the Popovic classification for radiolucency, the Chanlalit classification for stress shielding (SS), the Brooker classification for heterotopic ossification (HO), and the Broberg-Morrey classification for radiocapitellar arthritis, little is known about the reliability of these classification systems. The purpose of this study was to determine the interobserver and intraobserver reliability of these classifications. METHODS: Six orthopedic surgeons at various levels of training reviewed elbow radiographs of 20 patients who underwent RHA and classified them according to the Popovic, Chanlalit, Brooker, and Broberg-Morrey classifications for radiolucency, SS, HO, and RHA, respectively. Four weeks after initial review, radiographic reviews were repeated. Reliability was measured using the Fleiss kappa and the intraclass correlation coefficient. Agreement was interpreted as none (<0), slight (0.01-0.2), fair (0.21-0.4), moderate (0.41-0.6), substantial (0.61-0.8), and almost perfect (0.81-1) based on agreement among attending surgeons. RESULTS: Among fellowship-trained attending surgeons, interobserver reliability was slight for SS (Chanlalit) and the categorical interpretation of radiolucency (Popovic), fair for radiocapitellar arthritis (Broberg-Morrey) and HO (Brooker), and substantial for the ordinal interpretation of radiolucency (Popovic). Residents had a higher interobserver reliability than attending physicians when using the Brooker classification. Mean intraobserver reliability was fair for SS (Chanlalit) and the categorical interpretation of radiolucency (Popovic), moderate for HO (Brooker) and radiocapitellar arthritis (Broberg-Morrey), and almost perfect for the ordinal interpretation of radiolucency (Popovic). Trainees had higher intraobserver reliability than attending surgeons using the SS (Chanlalit) classification. CONCLUSIONS: The number of Popovic zones is reliable for communication between physicians, but caution should be taken with the Brooker, Chanlalit, Broberg-Morrey, and categorical interpretation of the Popovic classifications. All the classifications had better intraobserver than interobserver reliability. CLINICAL RELEVANCE: Reliability of classification systems for radiographic complications after RHA is less than substantial except the number of zones of radiolucency; therefore, caution is required when drawing conclusions based on these classifications.

No Correlation Between Clinical Outcomes and Changes in the Tibia-Metaphyseal Angle Following Total Knee Arthroplasty: A Retrospective Study.

BACKGROUND: Despite numerous advances in the implant design and surgical technique, improvement in patient satisfaction following total knee arthroplasty (TKA) has plateaued. Various TKA alignment strategies have been introduced that impact the coronal positioning of the tibial component relative to the native joint line. This study aims to analyze if postoperative variance of the joint line from preoperative native alignment is correlated with changes in patient-reported outcomes following primary TKA. METHODS: A retrospective review of an academic center's patient population identified all primary TKAs between 2013 and 2021 with full-length, standing radiographs and patient-reported outcome measures (PROMs) data. These measures included the Knee injury and Osteoarthritis Outcome Score for Joint Replacement, Patient-Reported Outcome Measurement Information System, and Veterans RAND 12 scores. Preoperative and postoperative radiographic measurements for hip-knee angle, tibia-metaphyseal angle, tibial-axis orientation angle, and joint-line obliquity angle were recorded. Three-month, 1-year, and 2-year PROM scores were correlated with the change in degrees for each of the angles using a Spearman's correlation. A Mann-Whitney U-test was used to compare angular changes with a change in PROM scores. RESULTS: One hundred and ninety nine patients (204 knees) with a mean age of 67 years were included. Average follow-up was 23 months. Three-month, 1-year, and 2-year follow-up rates were 93%, 64%, and 34%, respectively. Improvements were seen across all PROMs regardless of an angular change. CONCLUSION: There were no clear correlations between PROMs and variation in joint line obliquity in the coronal plane. These data suggest that the magnitude of the variation in coronal tibial alignment from native alignment does not impact PROMs. Further study is indicated to correlate an angular change with functional measures.

Anatomic Radial Head Arthroplasty: The Importance of Implant Angle.

PURPOSE: Multifragmentary radial head and neck fractures not amenable to open reduction and internal fixation are usually treated with radial head arthroplasty (RHA). Although the optimal implant design is still subject to debate, anatomic designs are common. We hypothesized that positioning of the implant leading to increased radial stem angle (RSA) (angle of the RHA stem with respect to the proximal radius shaft, RSA) in anatomic RHA designs will contribute to failures. The aim of this study was to characterize the risk of RHA failure with respect to the stem angle in anatomic RHA design. METHODS: A retrospective review of patients who underwent anatomic RHA for acute fractures between 2006 and 2019 at 2 academic centers was conducted. Initial postoperative elbow radiographs were reviewed to measure RSA on the anterior-posterior and lateral views. Radiolucency, stress shielding, and radiocapitellar arthritis were also evaluated. Implant failure was defined as prosthesis removal or revision. RESULTS: Implant failure was associated with significantly larger lateral RSA than that in intact implants. Increasing stem shaft angle on a lateral radiograph was associated with decreased implant survival. Radiolucency, stress shielding, and radiocapitellar arthritis were similar between the 2 groups. CONCLUSIONS: Anatomic radial head implants are commonly used; however, the importance of prosthesis positioning, specifically that of the stem within the proximal radius, remains understudied. Higher RSA is associated with the risk of implant failure and need for revision. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Comparison of computed tomography angiography and physical exam in the evaluation of arterial injury in extremity trauma.

BACKGROUND: CT angiography (CTA) is increasingly used in the evaluation of arterial injury in extremity trauma. While it may provide additional objective data, it comes with inherent risks and expense. The purpose of this study was to compare CTA to physical exam in the evaluation of arterial injury in extremity trauma. METHODS: We performed a retrospective review of patients who underwent CTA for evaluation of upper or lower extremity trauma at a Level 1 trauma center over a 10 month period. Patients were classified based on initial vascular exam (normal, soft signs, hard signs), and arterial injury on CTA was classified as major (named arteries) or minor (un-named arteries). We evaluated rates of vascular intervention in each group and compared the sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) for physical exam and CTA in identifying arterial injury requiring intervention. RESULTS: A total of 135 CTA studies were included. On initial vascular exam, 71% of patients had a normal exam, 22% had soft signs, and 6% had hard signs. The NPVs for arterial injury requiring intervention of a normal physical exam and negative CTA were both 100%. The PPVs for arterial injury requiring intervention of major injury on CTA and hard signs on physical exam were 35% and 50%, respectively. CONCLUSION: A normal physical exam can likely rule out the need for vascular intervention and eliminate the need for CTA. Additionally, the presence of hard signs on physical exam is potentially superior to CTA in predicting the need for vascular intervention.