Epidemiology of patellar dislocations in the United States from 2001 to 2020: results of a national emergency department database

OBJECTIVES

Recent studies have shown an increasing incidence of patellar dislocations among children and adolescents. Updated, population-based studies of all patellar dislocations in the United States (US), however, are lacking. This study investigated recent trends in injury rates and demographics among patients sustaining patellar dislocations in the US from 2001 to 2020.

METHODS

This descriptive epidemiologic study retrospectively analyzed the National Electronic Injury Surveillance System (NEISS) database to identify cases of acute patellar dislocations presenting to US Emergency Departments (EDs) from 2001 to 2020. Annual, overall, and age-adjusted incidence rates (IRs, expressed per 100,000 at-risk person-years) and additional patient/injury characteristics were analyzed. Average annual percent change (AAPC) estimates are presented to indicate the magnitude/direction of trends in annual injury rates.

RESULTS

An estimated total of 159,529 patellar dislocations occurred over the study period for an overall IR of 2.58 (95% CI = 2.04-3.12). Accounting for population growth, the overall annual incidence increased significantly from 2.61 in 2001 to 3.0 in 2020 (AAPC = 2.8, p < 0.0001). When considering sex and age, statistically significant increases in annual IRs were observed among males aged 10-19 years (AAPC = 3.8, p < 0.0001), females aged 10-19 years (AAPC = 5.3, p < 0.0001), and females aged 20-29 years (AAPC = 3.5, p = 0.0152), while no significant changes were observed in any other age groups. Two-thirds of patellar dislocations involved sports-related injury mechanisms. The annual incidence of both sports-related and non-sports-related injuries increased significantly over the study period (sports-related: AAPC = 2.6, p = 0.0001; non-sports-related: AAPC = 3.4, p = 0.0001). Athletic patellar dislocations occurred most commonly in basketball and dance.

CONCLUSION

The number of patients sustaining patellar dislocations is increasing in the US. Similar increasing trends were observed in both males and females aged 10-19 years, whereas injury rates increased in the third decade only among females. A large percentage of injuries occur during athletic activity, but both sports- and non-sports-related patellar dislocations are on the rise.

The statistical fragility of intramedullary reaming in tibial nail fixation: a systematic review

PURPOSE

To report the statistical stability of prospective clinical trials evaluating the effect of intramedullary reaming on rates of non-union in tibial fractures through calculation of the fragility metrics for non-union rates and all other dichotomous outcomes.

METHODS

Literature search was conducted for prospective clinical trials evaluating the effect of intramedullary reaming on non-union rates in tibial nailing. All dichotomous outcomes were extracted from the manuscripts. The fragility index (FI) and reverse fragility index (RFI) were calculated by determining the number of event reversals required for a statistically significant outcome to lose significance and vice-versa. The fragility quotient (FQ) and reverse fragility quotient (RFQ) were calculated by dividing the FI or RFI by the sample size, respectively. Outcomes were defined as "fragile" if the FI or RFI was found to be less than or equal to the number of patients lost to follow-up.

RESULTS

Literature search identified 579 results which produced ten studies meeting the criteria for review. There were 111 outcomes identified for analysis, of which 89 (80%) exhibited statistical fragility. For reported outcomes across the studies the median and mean FI was 2, the median FQ was 0.019, the mean FQ was 0.030, the median RFI was 4, the mean RFI was 3.95, the median RFQ was 0.045, and the mean RFQ was 0.030. Four studies reported outcomes which were found to have an FI of 0.

CONCLUSIONS

The studies evaluating the effect of intramedullary reaming on tibial nail fixation demonstrate considerable fragility. On average, two event reversals for significant findings, and four event reversals for insignificant findings are sufficient to alter statistical significance.

LEVEL OF EVIDENCE

Level II, systematic review of Level I and Level II studies.

Trends and epidemiology of knee extensor mechanism injuries presenting to United States emergency departments from 2001 to 2020

OBJECTIVES

Injuries to the native extensor mechanism (EM) of the knee are potentially disabling and often require surgical treatment. Large-scale, updated epidemiological data on these injuries is lacking. The objective of the current study was to examine recent trends in EM injuries presenting to United States (US) Emergency Departments (EDs) over the last 20 years using a nationally representative sample.

METHODS

This study retrospectively analyzed the National Electronic Injury Surveillance System (NEISS) database to identify cases of EM injuries (defined as either a quadriceps tendon rupture, a patella fracture, or a patellar tendon rupture) presenting to EDs in the US from 2001 to 2020.

RESULTS

During the study period, an estimated 214,817 EM injuries occurred in an at-risk population of 6,183,899,410 person-years for an overall incidence rate of 3.47 per 100,000 person-years. Patella fractures (PFs) were the most common injury type, representing 77.5% of all EM injuries (overall incidence rate: 2.69), followed by patellar tendon ruptures (PTRs; 13.5%; incidence: 0.48) and quadriceps tendon ruptures (QTRs; 9%; incidence: 0.31). Demographic characteristics and mechanisms of injury differed between injury types. Annual incidence rates increased significantly during the study period for all EM injury types, with PTRs demonstrating the largest relative increase (average annual percent increase: PF, 2.8%; PTR, 7.2%; QTR, 5.3%). Accounting for population growth yielded an increasing incidence of all EM injuries combined from 3.65 in 2001 to 4.9 in 2020. The largest relative increases in incidence rates were observed in older age groups.

CONCLUSION

Extensor mechanism injuries of the knee are increasing in the US, which likely reflects an aging and more active population. These types of injuries are associated with substantial functional impairment and recent increases in incidence rates highlight the need for injury prevention and management strategies.

Funding has no effect on clinical outcomes of total joint arthroplasty emerging technologies: a systematic review of bibliometrics and conflicts of interest

Background

The use of new total joint arthroplasty technologies, including patient-specific implants/instrumentation (PSI), computer-assisted (CA), and robotic-assisted (RA) techniques, is increasing. There is an ongoing debate regarding the value provided and potential concerns about conflicts of interest (COI).

Methods

PRISMA guidelines were followed. PubMed, MEDLINE, and Web of Science databases were searched for total hip and knee arthroplasties, unicompartmental knee arthroplasties (UKA), PSI, CA, and RA. Bibliometric data, financial COI, clinical/functional scores, and patient-reported outcomes were assessed.

Results

Eighty-seven studies were evaluated, with 35 (40.2%) including at least one author reporting COI, and 13 (14.9%) disclosing industry funding. COI and industry funding had no significant effects on outcomes (P = 0.682, P = 0.447), and there were no significant effects of conflicts or funding on level of evidence (P = 0.508, P = 0.826). Studies in which author(s) disclosed COI had significantly higher relative citation ratio (RCR) and impact factor (IF) than those without (P < 0.001, P = 0.032). Subanalysis demonstrated RA and PSI studies were more likely to report COI or industry funding (P = 0.045). RA (OR = 6.31, 95% CI: 1.61–24.68) and UKA (OR = 9.14, 95% CI: 1.43–58.53) had higher odds of reporting favorable outcomes than PSI.

Conclusions

Author COIs (about 40%) may be lower than previously reported in orthopedic technologies/techniques reviews. Studies utilizing RA and PSI were more likely to report COI, while RA and UKA studies were more likely to report favorable outcomes than PSI. No statistically significant association between the presence of COIs and/or industry funding and the frequency of favorable outcomes or study level of evidence was found.

Level of evidence

Level V Systematic Review

Supplementary Information

The online version contains supplementary material available at 10.1186/s42836-022-00146-3.

Effects of veterans' mental health service-connections on patient-reported outcomes following total joint arthroplasty

Background

Studies report poor outcomes of elective orthopaedic surgeries among civilian patients receiving Workers' Compensation (WC). However, little is known about surgical outcomes in veterans receiving similar benefits through the Veterans Affairs (VA) service-connected (SC) disability compensation program.

Methods

Veterans undergoing primary total hip arthroplasty (THA) or total knee arthroplasty (TKA) at a VA Medical Center between 07/2019-12/2021 were analyzed by SC status. Outcomes were evaluated using Hip disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR) and Knee injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) scores collected preoperatively and at 2- and 12-months postoperatively. Repeated measures mixed models were used to test for the effect of SC on HOOS-JR/KOOS-JR scores, controlling for baseline age, sex, and Charlson Comorbidity Index (CCI). SC and baseline joint function (stratified into quartiles using baseline HOOS-JR/KOOS-JR scores) were analyzed for effects on achieving substantial clinical benefit (SCB) at 12-month follow-up.

Results

The analysis included 67 hips and 142 knees. SC and non-SC (NSC) veterans had similar baseline HOOS-JR/KOOS-JR and CCI. HOOS-JR remained similar between groups through 12 months (79.9 ± 19.2 vs. 82.7 ± 18.8) as did KOOS-JR (70.4 ± 15.6 vs. 74.6 ± 15.3). The designation of any SC and mental health SC reached significance for KOOS-JR (P = 0.034 and P = 0.032, respectively). For HOOS-JR and KOOS-JR, baseline function score quartile significantly influenced final score (P < 0.001), with patients in the lowest quartiles (i.e., worst baseline function) exhibiting significantly greater improvements than patients in higher quartiles.

Conclusions

Mental health SC and high preoperative functional status are variables that may have unfavorable influences on self-reported outcomes of TKA in veteran patients. SC status does not appear to influence the outcomes of THA or the likelihood of achieving SCB after either THA or TKA. Regardless of SC status, most veterans can expect significant clinical improvements after total joint arthroplasty.

A review of current practices in periprosthetic joint infection debridement and revision arthroplasty

BACKGROUND

Periprosthetic joint infection remains a significant challenge for arthroplasty surgeons globally. Over the last few decades, there has been much advancement in terms of treatment and diagnosis, however, the fight rages on. As management of periprosthetic joint infections continues to evolve, it is critical to reflect back on current debridement practices to establish common ground as well as identify areas for future research and improvement. BODY: In order to understand the debridement techniques of periprosthetic joint infections, one must also understand how to diagnose a periprosthetic joint infection. Multiple definitions have been elucidated over the years with no single consensus established but rather sets of criteria. Once a diagnosis has been established the decision of debridement method becomes whether to proceed with single vs two-stage revision based on the probability of infection as well as individual patient factors. After much study, two-stage revision has emerged as the gold standard in the management of periprosthetic infections but single-stage remains prominent with further and further research.

CONCLUSION

Despite decades of data, there is no single treatment algorithm for periprosthetic joint infections and subsequent debridement technique. Our review touches on the goals of debridement while providing a perspective as to diagnosis and the particulars of how intraoperative factors such as intraarticular irrigation can play pivotal roles in infection eradication. By providing a perspective on current debridement practices, we hope to encourage future study and debate on how to address periprosthetic joint infections best.

Virtual Interviews in the Era of COVID-19: Expectations and Perceptions of Orthopaedic Surgery Residency Candidates and Program Directors

Background:

Orthopaedic surgery residency program directors (PDs) and candidates consider interviews to be central to the application process. In-person interviews are typical, but virtual interviews present a potentially appealing alternative. Candidate and PD expectations and perceptions of virtual interviews during the 2020/2021 orthopaedic surgery application cycle were assessed.

Methods:

Candidates and PDs were surveyed electronically. Questions covered pre–virtual-interview and post–virtual-interview expectations and perceptions, and past in-person experiences (PDs and reapplicants) on the relative importance of application components, ability to assess fit, interview costs, and preferred interview mode. Identical questions allowed between-group comparisons.

Results:

Responses included n = 29 PDs and n = 99 candidates. PDs reported diminished ability to assess candidate fit; social, clinical, and surgical skills; and genuine interest in the virtual context (each p ≤ 0.01). They placed greater importance on research and less on the interview in the virtual vs. in-person context (each p = 0.02). Most candidates (78%) reported fair/good ability to demonstrate potential and were better able to assess research opportunities than expected (p < 0.01). Candidates expected virtual interviews to increase the importance of research, transcripts, and recommendations (for each, p ≤ 0.02) and decrease the importance of the interview itself (p < 0.01). Compared with PDs, candidates overvalued research, United States Medical Licensing Examination scores, transcripts, and recommendations (each p ≤ 0.02) and may have slightly undervalued the virtual interview (p = 0.08). Most candidates (81%) and PDs (79%) preferred in-person interviews, despite both groups reporting monetary savings.

Conclusions:

Despite cost savings associated with virtual interviews, orthopaedic surgery residency PDs and candidates identified reduced abilities to assess candidate or program fit and displayed a preference for in-person interviews.

Predictive Factors of Extended Length of Hospital Stay Following Total Joint Arthroplasty in a Veterans Affairs Hospital Population

BACKGROUND

Improved perioperative care for total joint arthroplasty (TJA) procedures has resulted in decreased hospital length of stay (LOS), including effective discharge on postoperative day (POD) 1 in many patients. It remains unclear what contributes to discharge delay in patients that are not discharged on POD 1. This study investigated factors associated with delayed discharge in patients whose original planned discharge was on POD 1.

METHODS

A retrospective cohort of 451 patients who underwent a hip or knee TJA procedure from April 2015 to March 2018 with planned discharge on POD 1 was analyzed. Patient characteristics included demographics, lab values, course of treatment, procedure, Charlson Comorbidity Index (CCI), complications, and other factors. Statistical regression was used to identify factors associated with delayed discharge; odds ratios (OR) were calculated for significant factors (α = 0.05).

RESULTS

Of those studied, 70/451 (15.5%) experienced a delay from the planned POD 1 discharge. An increased likelihood of delayed discharge was associated with a nonhome discharge (P < .001, OR = 8.72 [95% CI: 4.22-18.06]) and higher CCI (P = .034, OR = 1.16 [95% CI: 1.01-1.32]). Inpatient physical therapy on the day of surgery was found to significantly correlate with successful discharge on POD 1 (P = .004, OR = 0.44 [95% CI: 0.25-0.77]).

CONCLUSION

Most patients can be discharged on POD 1 after TJA. Physical therapy on the day of surgery increased the likelihood of patients being discharged on POD 1. Those with a higher CCI and a nonhome discharge were more likely to have a discharge delay. This information can help surgeons counsel patients and prepare for postoperative care.

5- to 13-year follow-up study on cementless femoral components in revision surgery

The 5- to 13-year follow-up data on 297 cementless revision arthroplasties with extensively coated components (Anatomic Medullary Locking femoral component, DePuy, Warsaw, IN) are reported. A basic classification of the femoral defects was developed. All patients were evaluated clinically and radiographically at a minimum of 60 months. Clinically, the average Postel-d'Aubigné score improved from 4.8 before to a 10.2 after surgery. Definite radiographic instability was noted in seven hips. Five patients were symptomatic and were revised. The mechanical failure rate was 2.4%. The overall complication rate was 5.7%, with a 2.6% dislocation rate. In the presence of bone loss in the proximal metaphyseal region of the femur, fixation of the femoral component is best achieved in the diaphyseal region of the femur using an extensively coated femoral component.