Clinically Significant Outcome Scores in Orthopaedic Sports Medicine Shoulder and Knee Surgery Are Increasing in Prevalence but Often Reported Incorrectly.

PURPOSE: To study the prevalence and quality of application of minimal clinically important difference (MCID), substantial clinical benefit (SCB), patient-acceptable symptomatic state (PASS), and maximum outcome improvement (MOI), reported in the orthopaedic sports medicine knee and shoulder literature in recent years and to bring awareness of proper use of such metrics. METHODS: A literature review of all shoulder and knee articles published from the American Journal of Sports Medicine (AJSM), Journal of Shoulder and Elbow Surgery (JSES), and Arthroscopy from 2016 to 2020 was performed, specifically investigating whether MCID, SCB, PASS, or MOI were used or reported. Additionally, the way these metrics were reported and interpreted was recorded. RESULTS: Out of 5,039 studies, 889 shoulder and knee studies met the inclusion criteria. Overall, 16.7% reported either MCID, PASS, or SCB. MCID was the most reported across all 3 journals. MCID was reported 12.4% of the time throughout the 5 years. PASS was reported 3.2% and SCB 1.1% of the time over the 5 years. MOI was not reported by any of the journals during this period. There was a statistically significant increase in MCID reporting in 2 of the 3 journals over the 5-year course, Arthroscopy (P = .02) and AJSM (P = .05). There was no statistically significant increase in PASS or SCB reporting rates in all 3 journals. Only 39.1% of studies reported MCID correctly (i.e., defined as the number of individual patients meeting MCID/total patients in the study). CONCLUSIONS: This study shows an increasing trend in the use of clinically significant outcome metrics, such as MCID, for interpretation of patient-reported outcomes; however, these individual metrics are often not being used on the individual level and subsequently not reported accurately. We recommend determining whether the specific metric met the threshold per individual patient and then reporting those as a percentage of the sample population to achieve the full potential of these metrics and translate them accurately across various studies. CLINICAL RELEVANCE: As the usage of clinically significant outcome metrics rises, so does the need for accurate reporting. These findings will encourage future studies to follow a more standardized format.

Gender Diversity in Orthopaedic Surgery Residencies Does Not Translate to Accreditation Council for Graduate Medical Education-Accredited Fellowships.

Introduction: Gender representation among orthopaedic surgery applicants and residents has increased over the past two decades. The aims of this study were to evaluate trends of female fellows in ACGME-accredited orthopaedic subspecialties between 2007 and 2021, and to compare the fellowship trends of female representation to those of ACGME-accredited orthopaedic residencies. Methods: We conducted a retrospective review of publicly available ACGME-accredited fellowship demographic data from 2007 to 2021. The distribution of genders (male vs. female) across subspecialties and orthopaedic surgery residency programs was compared. Chi-square, Spearman correlation, and logistic regression tests were performed to analyze the relationships between year, gender, and fellowship. Results: Chi-square analysis demonstrated a significant relationship between gender and year for orthopaedic residency (p < 0.001), but not for any fellowship. There was a significant negative Spearman correlation between the two variables for hand (r(1844) = -0.06, p = 0.02) and sports medicine (r(2804) = -0.05, p = 0.01) fellowships. The negative Spearman correlation for pediatrics (r(499) = -0.09, p = 0.054) approached but did not reach statistical significance. Logistic regression analysis revealed that, holding year constant and comparing to orthopaedic residency, the odds of male participation increased by 173% (95% CI, 1.8-4.1) in spine, increased by 138% (95% CI, 1.7-3.3) in adult reconstruction, increased by 51% (95% CI, 1.3-1.7) in sports medicine, decreased by 41% (95% CI, 0.5-0.7) in hand, decreased by 36% (95% CI, 0.5-0.9) in foot and ankle, decreased by 48% (95% CI, 0.4-0.7) in musculoskeletal oncology, and decreased by 68% (95% CI, 0.3-0.4) in pediatrics. Conclusion: Although the percentage of female orthopaedic residents in ACGME-accredited programs increased significantly from 2007 to 2021, this has not translated to ACGME-accredited fellowship positions. Future research optimizing methods to improve the representation of females in orthopaedic surgery should be considered. Level of Evidence: III.

Peri-operative zoledronic acid attenuates peri-prosthetic osteolysis in a rat model of cemented knee replacement.

Progressive osteolysis can occur at the cement-bone interface of joint replacements and the associated loss of fixation can lead to clinical loosening. We previously developed a rat hemiarthroplasty model that exhibited progressive loss of fixation with the development of cement-bone gaps under the tibial tray that mimicked patterns found in human arthroplasty retrievals. Here we explored the ability of a bisphosphonate (zoledronic acid, ZA) to attenuate cement-bone osteolysis and maintain implant stability. Sprague-Dawley rats (n = 59) received a poly(methylmethacrylate) cemented tibial component and were followed for up to 12 weeks. Treatment groups included peri-operative administration of ZA (ZA group), administration of ZA at 6 weeks postop (late ZA group), or vehicle (Veh group). There was a 60% reduction in the rate of cement-bone gap formation for the ZA group (0.15 mm3/week) compared to Veh group (0.38 mm3/week, p = 0.016). Late ZA prevented further progression of gap formation but did not reverse bone loss to the level achieved in the ZA group. Micromotion from five times body weight toggle loading was positively correlated with cement-bone gap volume (p = 0.009) and negatively correlated with the amount of cement in the metaphysis (p = 0.005). Reduced new bone formation and enduring nonviable bone in the epiphysis for the ZA group were found. This suggests that low bone turnover in the epiphysis may suppress the early catabolic response due to implantation, thereby maintaining better fixation in the epiphysis. This preclinical model presents compelling supporting data documenting improved maintenance of the cement-bone fixation with the use of peri-operative bisphosphonates.

Progressive loss of implant fixation in a preclinical rat model of cemented knee arthroplasty.

Aseptic loosening of total knee arthroplasty continues to be a challenging clinical problem. The progression of the loosening process, from the initial well-fixed component, is not fully understood. In this study, loss of fixation of cemented hemiarthroplasty was explored using 9-month-old Sprague-Dawley rats with 0, 2, 6, 12, 26 week end points. Morphological and cellular changes of cement-bone fixation were determined for regions directly below the tibial tray (epiphysis) and distal to the tray (metaphysis). Loss of fixation, with a progressive increase in cement-bone gap volume was found in the epiphysis (0.162 mm3 /week), but did not progress appreciably in the metaphysis (0.007 mm3 /week). In the epiphysis, there was an early and sustained elevation of osteoclasts adjacent to the cement border and development of a fibrous tissue layer between the cement and bone. There was early formation of bone around the cement in the metaphysis, resulting in a condensed bone layer without osteoclastic bone resorption or development of a fibrous tissue layer. Implant positioning was also an important factor in the cement-bone gap formation, with greater gap formation for implants that were placed medially on the tibial articular surface. Loss of fixation in the rat model mimicked patterns found in human arthroplasty where cement-bone gaps initiate under the tibial tray, at the periphery of the implant. This preclinical model could be used to study early biological response to cemented fixation and associated contributions of mechanical instability, component alignment, and periprosthetic inflammation.

Similitude of cement-bone micromechanics in cemented rat and human knee replacement.

A preclinical rat knee replacement model was recently developed to explore the biological and mechanobiological changes of trabecular resorption for cement-bone interdigitated regions. The goal here was to evaluate the relevance of this model compared with human knee replacement with regards to functional micromechanics. Eight nonsurvival, cemented knee replacement surgeries were performed, the interdigitated gap morphology was quantified, and interface micromotion between cement and bone was measured for 1 to 5 bodyweight loading. Computational fluid dynamics modeling of unit cell geometries with small gaps between trabeculae and cement was used to estimate fluid flow. Gap width (3.6 µm) was substantially smaller compared with cement-bone gaps reported in human knee replacement (11.8 µm). Micromotion at the cement-bone border was also decreased for the rat knee replacement (0.48 µm), compared with human (1.97 µm), for 1 bodyweight loading. However, the micromotion-to-gap width ratio (0.19 and 0.22 for, rat and human), and estimated fluid shear stress (6.47 and 7.13 Pa, for rat and human) were similar. Replicating the fluid dynamic characteristics of cement-bone interdigitated regions in human knee replacements using preclinical models may be important to recapitulate trabecular resorption mechanisms due to proposed supraphysiologic fluid shear stress. Statement of clinical significance: local cement-bone micromotion due to joint loading may contribute to the process of clinical loosening in total joint replacements. This work shows that while micromotion and gap morphology are diminished for the rat knee model compared to human, the motion-to-gap ratio, and corresponding fluid shear stress are of similar magnitudes.