The Statistical Fragility of Single-Bundle vs Double-Bundle Autografts for ACL Reconstruction: A Systematic Review of Comparative Studies

Notchplasty in anterior cruciate ligament reconstruction: A systematic review of clinical outcomes

Introduction

Notchplasty is an adjuvant procedure performed during Anterior Cruciate Ligament reconstruction (ACLR) with the purpose of widening the intercondylar notch of the femur. Its use is controversial due to its biomechanical influence on the knee and the potential for increased complications. The purpose of this systematic review is to evaluate the outcomes of patients who underwent ACLR with notchplasty.

Materials and methods

A systematic search of Cochrane, Embase, and Medline was conducted to identify papers evaluating clinical outcomes of patients who underwent ACLR with notchplasty. Inclusion criteria encompassed human studies with a control group, reporting clinical outcomes such as graft failure, graft rupture, range of motion values, and patient-reported outcomes.

Results

A total of 4 studies were included comprising 396 patients (129 with notchplasty, 235 without). No significant differences were reported regarding graft survivability or Lysholm score between those with notchplasty and those without. One study reported significantly reduced rates of revision surgery after ACLR with notchplasty. There were conflicting complication rates between studies regarding chronic synovitis and arthrofibrosis.

Conclusion

Patients who undergo notchplasty during primary ACLR have similar outcome scores and risk of graft failure compared to those who do not undergo notchplasty. Notchplasty patients may also be at a higher risk for loss of extension and chronic synovitis.

Randomized trials evaluating volar locking plates against casting of distal radius fractures are statistically fragile: A systematic review

Introduction

Despite randomized controlled trials (RCTs) largely supporting volar locking plates (VLPs) for the management of distal radius fractures (DRFs), surgeons often opt for non-invasive interventions such as casting. This study used the fragility index (FI), reverse fragility index (rFI), and fragility quotient (FQ) to assess the statistical robustness of RCTs assessing the efficacy of VLP in DRF management.

Methods

PubMed, Embase, and MEDLINE were queried for RCTs evaluating VLP versus casting for DRFs published from January 1st, 2000-June 30, 2024. FI and rFI were quantified for all dichotomous outcomes, and represent the number of event reversals required to alter statistical significance or non-significance, respectively. The FQ was then determined by dividing the FI or rFI by the sample size. A subanalysis was performed for outcomes pertaining to patient satisfaction, healing/function, and adverse events.

Results

A total of 699 RCTs were identified in the initial literature search. 13 RCTs were eventually included in the final analysis, yielding 36 dichotomous outcomes. The median FI across these outcomes was 3 (IQR 3-5) and the median FQ was 0.037 (IQR 0.014-0.067). Among the 15 significant outcomes, the median FI was 2 (IQR 2-4) and the median FQ was 0.029 (IQR 0.013-0.055). The remaining 21 non-significant outcomes yielded a median rFI of 4 (IQR 2-5) and a median FQ of 0.042 (IQR 0.021-0.091). The most statistically fragile outcome category was patient satisfaction, with a median FI of 2 (IQR 2-3.5) and median FQ of 0.016 (IQR 0.013-0.030). Among 21 of the included outcomes (58.3 %), the number of patients lost to follow up exceeded the respective FI or rFI.

Conclusion

A statistical fragility analysis of VLP versus casting for DRFs demonstrated fragile outcomes, reporting a median FQ of 0.037, or 3.7 %. Statistically significant outcomes and patient satisfaction results were particularly fragile, and large losses to follow up were found to be an important contributor to RCT fragility. Although VLP is largely recommended by level I evidence, its superiority may not be as ubiquitous as argued by contemporary literature.

Fragility of Statistical Differences Between Surgical Approaches in Total Hip Arthroplasty

BACKGROUND

Total hip arthroplasty (THA) is a successful treatment for hip osteoarthritis, but the optimal surgical approach for this procedure is a topic of debate. This review uses fragility analysis to determine the statistical fragility of randomized controlled trials (RCTs) comparing the 3 most common surgical approaches for THA: direct anterior, direct lateral, and posterior.

MATERIALS AND METHODS

A systematic review was conducted to identify RCTs comparing 2 of the 3 surgical approaches for THA. Dichotomous outcomes and study characteristics were extracted from each study that met the inclusion criteria. Fragility index (FI) and fragility quotient (FQ) were calculated for each significant outcome (P≤.05), and reverse fragility index and quotient (rFI and FQ) were calculated for each nonsignificant outcome (P>.05).

RESULTS

Our search yielded 20 studies in total, with 146 identified dichotomous outcomes. In total, the outcomes had a median FI of 5 and a median rFI of 5. Significant outcomes that favored the anterior approach had a median FI of 6, and significant outcomes that favored the posterior or lateral approach both had a median FI of 1.

CONCLUSION

The RCTs comparing approaches to THA had a median FI of 5, signifying that the reversal of 5 events would be sufficient to change the significance of the entire outcome. This value is comparable to other FI values within the orthopedic literature, but subgroup analyses elucidated areas of greater statistical fragility, particularly in outcomes favoring either the lateral or posterior approach in THA. [Orthopedics. 202x;4x(x):xx-xx.].

The Statistical Fragility of Patellar Resurfacing in Total Knee Arthroplasty: A Systematic Review of Randomized Controlled Trials

BACKGROUND

Randomized controlled trials (RCTs) evaluating patellar resurfacing in total knee arthroplasty (TKA) have conflicting findings, with some reporting its efficacy and others demonstrating no clinical significance. The fragility index (FI), reverse FI (rFI), and fragility quotient (FQ) evaluated statistical fragility of outcomes in RCTs evaluating patellar resurfacing in TKA.

METHODS

The PubMed, Embase, and MEDLINE databases were systematically searched for RCTs (January 1, 2000, to August 1, 2023) assessing patellar resurfacing in TKA. Of the 226 RCTs screened, 19 studies were included for analysis. We calculated FI and rFI, which represent the number of outcome event reversals required to alter statistical significance for significant and nonsignificant outcomes, respectively. The outcome categories of interest included anterior knee pain, complications/adverse events, crepitus, reoperation, patient satisfaction, and clinical improvement. The FQ was determined by dividing the FI by the study sample size.

RESULTS

Across 46 outcomes, the median FI was 5 (interquartile range (IQR) 3 to 8) with a median FQ of 0.041 (IQR 0.025 to 0.063). There were nine outcomes that were statistically significant, with a median FI of 3 (IQR 2 to 8) and a FQ of 0.011 (IQR 0.0044 to 0.039). There were 37 outcomes that were nonsignificant, with a median rFI of 5 (IQR 4 to 7) and FQ of 0.043 (IQR 0.031 to 0.062). Notably, in 47.8% of all outcomes, the number of patients lost to follow-up was greater than the outcome's respective FI or rFI. Outcomes regarding patient satisfaction (FI 4.5) and anterior knee pain (FI 5) were most fragile.

CONCLUSIONS

The outcomes of interest regarding patellar resurfacing from RCTs are statistically fragile, particularly significant outcomes and patient satisfaction outcomes. Data surrounding patellar resurfacing remain inconclusive, and combining P values with FI/FQ metrics may aid in interpreting patellar resurfacing findings. Future studies may mitigate fragility by obtaining higher follow-up rates and sample sizes.

LEVEL OF EVIDENCE

I.

Randomized Controlled Trials Evaluating Treatments for Carpometacarpal Arthritis Are Statistically Fragile: A Systematic Review

BACKGROUND

Randomized controlled trials (RCTs) on carpometacarpal (CMC) arthritis have a significant impact on treatment decisions, yet the robustness of their findings is seldom evaluated. This study aims to investigate the statistical fragility of RCTs evaluating treatments for CMC arthritis.

METHODS

PubMed, Embase, and MEDLINE were systematically searched for recent RCTs (2010-2023) evaluating treatment variations for CMC arthritis. The fragility index (FI) or reverse FI (rFI) was calculated for each dichotomous outcome, representing the number of event reversals required to alter statistical significance for significant and nonsignificant outcomes, respectively. The fragility quotient (FQ) was determined by dividing the FI or rFI by the total sample size.

RESULTS

Of the 46 RCTs screened for inclusion, 15 were included for analysis, resulting in 46 total outcomes. The median FI across the 46 outcomes was 4.5, with an associated median FQ (mFQ) of 0.075. Statistically significant outcomes were more fragile (mFQ = 0.026) than nonsignificant outcomes (mFQ = 0.079). In 66.7% of significant outcomes, losses to follow-up were greater than that outcome's FI. Postoperative functional tests, adverse events, and patient satisfaction were the most common outcome categories reported, with mFQ's of 0.170, 0.066, and 0.068, respectively.

CONCLUSIONS

Outcomes reported in RCTs studying CMC arthritis are statistically fragile, particularly among significant outcomes where losses to follow-up may have also affected outcome significance. For future studies, we recommend reporting fragility statistics along with P values to provide hand surgeons another metric by which to gauge the results of CMC RCTs.

The Statistical Fragility of Marrow Stimulation for Cartilage Defects of the Knee: A Systematic Review of Randomized Controlled Trials

OBJECTIVE

Marrow stimulation is used to address knee cartilage defects. In this study, we used the fragility index (FI), reverse fragility index (rFI), and fragility quotient (FQ) to evaluate statistical fragility of outcomes reported in randomized controlled trials (RCTs) evaluating marrow stimulation.

DESIGN

PubMed, Embase, and MEDLINE were queried for recent RCTs (January 1, 2010-September 5, 2023) assessing marrow stimulation for cartilage defects of the knee. The FI and rFI were calculated as the number of outcome event reversals required to alter statistical significance for significant and nonsignificant outcomes, respectively. The FQ was determined by dividing the FI by the study sample size.

RESULTS

Across 155 total outcomes from 21 RCTs, the median FI was 3 (interquartile range [IQR], 2-5), with an associated median FQ of 0.067 (IQR, 0.033-0.010). Thirty-two outcomes were statistically significant, with a median FI of 2 (IQR, 1-3.25) and FQ of 0.050 (IQR, 0.025-0.069). Ten of the 32 (31.3%) outcomes reported as statistically significant had an FI of 1. In total, 123 outcomes were nonsignificant, with a median rFI of 3 (IQR, 2-5). Studies assessing stem cell augments were the most fragile, with a median FI of 2. In 55.5% of outcomes, the number of patients lost to follow-up was greater than or equal to the FI.

CONCLUSION

Statistical findings in RCTs evaluating marrow stimulation for cartilage defects of the knee are statistically fragile. We recommend combined reporting of P-values with FI and FQ metrics to aid in the interpretation of clinical findings in comparative trials assessing cartilage restoration.

The Statistical Fragility of Lateral Extra-articular Tenodesis Research: A Systematic Review

Background

A P value of <.05 is often used to denote statistical significance; however, in many scenarios, this threshold is vulnerable to a small number of outcome reversals. This study joins a body of studies within the orthopaedic literature that evaluate the statistical fragility of existing research via metrics such as fragility index (FI) and fragility quotient (FQ).

Purpose/Hypothesis

The purpose of this study was to investigate the statistical fragility of randomized controlled trials (RCTs) and comparative studies on the topic, given the resurgent interest in lateral extra-articular tenodesis (LET) to augment primary or revision anterior cruciate ligament reconstruction (ACLR). It was hypothesized that the outcomes reported in these studies would be statistically fragile.

Study Design

Systematic review; Level of evidence, 4.

Methods

Comparative studies and RCTs regarding LET as an adjunct procedure to ACLR published between 2000 and 2022 were analyzed. Descriptive characteristics, dichotomous outcomes, and continuous outcomes were extracted. The FI and continuous FI (CFI) were calculated by the number of event reversals to change significance; the FQ and continuous FQ (CFQ) were calculated to normalize the fragility metrics per sample size.

Results

Of 455 studies screened, 29 studies were included (9 RCTs, 20 comparative); 79.3% of included studies were published after 2020. A total of 48 dichotomous and 265 continuous outcomes were analyzed. The median FI was 9.0 (IQR, 7.0-13.3), with FQ of 0.1 (IQR, 0.04-0.17); the median CFI was 7.8 (IQR, 4.2-19.6), with CFQ of 0.12 (IQR, 0.08-0.19). The FQ and CFQ for studies on LET with revision ACLR were larger (0.117 and 0.113, respectively) than those focused on primary ACLR (0.042 and 0.095, respectively).

Conclusion

Studies focused on LET with primary ACLR were more fragile than those on LET with revision, which suggests that further research on the indications for LET with primary ACLR is necessary. Future orthopaedic comparative research should include fragility metrics alongside traditional P values.

Interpreting the Current Literature on Outcomes of Robotic-Assisted Versus Conventional Total Knee Arthroplasty Using Fragility Analysis: A Systematic Review and Cross-Sectional Study of Randomized Controlled Trials

BACKGROUND

Fragility analysis is a method of further characterizing outcomes in terms of the stability of statistical findings. This study assesses the statistical fragility of recent randomized controlled trials (RCTs) evaluating robotic-assisted versus conventional total knee arthroplasty (RA-TKA versus C-TKA).

METHODS

We queried PubMed for RCTs comparing alignment, function, and outcomes between RA-TKA and C-TKA. Fragility index (FI) and reverse fragility index (RFI) (collectively, "FI") were calculated for dichotomous outcomes as the number of outcome reversals needed to change statistical significance. Fragility quotient (FQ) was calculated by dividing the FI by the sample size for that outcome event. Median FI and FQ were calculated for all outcomes collectively as well as for each individual outcome. Subanalyses were performed to assess FI and FQ based on outcome event type and statistical significance, as well as study loss to follow-up and year of publication.

RESULTS

The overall median FI was 3.0 (interquartile range, [IQR] 1.0 to 6.3) and the median reverse fragility index was 3.0 (IQR 2.0 to 4.0). The overall median FQ was 0.027 (IQR 0.012 to 0.050). Loss to follow-up was greater than FI for 23 of the 38 outcomes assessed.

CONCLUSIONS

A small number of alternative outcomes is often enough to reverse the statistical significance of findings in RCTs evaluating dichotomous outcomes in RA-TKA versus C-TKA. We recommend reporting FI and FQ alongside P values to improve the interpretability of RCT results.

Lateral femoral tunnel preparation and graft fixation for anterior cruciate ligament reconstruction-A discussion

This article provides a discussion and commentary around the recent advances in arthroscopic anterior cruciate ligament reconstruction (ACLR), with a focus on the aspects of lateral femoral tunnel preparation and graft fixation techniques. The paper explores and comments on a recently published review by Dai et al, titled "Research progress on preparation of lateral femoral tunnel and graft fixation in ACLR", while providing insight into its relevance within the field of ACLR, and recommendations for future research.

The Reverse Fragility Index: Interpreting the Evidence for Arthroscopic Rotator Cuff Repair Healing Associated With Early Versus Delayed Mobilization

Background: The American Academy of Orthopaedic Surgeons (AAOS) clinical practice guidelines (CPGs) note "strong" evidence that early and delayed mobilization protocols after small to medium arthroscopic rotator cuff repairs achieve similar rotator cuff healing rates. Purpose: We utilized the reverse fragility index (RFI) to assess the fragility of randomized controlled trials (RCTs) reporting no statistically significant difference in tendon re-tear rates after rotator cuff repair in those undergoing early versus delayed rehabilitation. Methods: Randomized controlled trials used in the most recent AAOS CPGs on the timing of postoperative mobilization after arthroscopic rotator cuff repairs were analyzed. Only RCTs with a reported P value ≥ .05 were included. The RFI at a threshold of P < .05 was calculated for each study. The reverse fragility quotient (RFQ) was calculated by dividing the RFI by the study sample size. Results: In 6 clinical trials with a total of 542 patients, the number of tendon re-tear events was 48. The median RFI at the P < .05 threshold was 4 (range: 3.25-4.75), and the median RFQ was .05 (range: 0.03-0.08). The median loss to follow-up was 6 patients. Of the 6 studies investigated, 3 reported a loss to follow-up greater than their respective RFI. Conclusion: The equivalence in rotator cuff repair healing rates associated with early and delayed mobilization protocols rests on fragile studies, as their statistical non-significance can be reversed by changing the outcome status of only a handful of patients. Consideration should be given to the routine reporting of RFI in clinical practice guidelines including RCTs with statistically non-significant results.

Statistical Fragility Analysis of Open Reduction Internal Fixation vs Primary Arthrodesis to Treat Lisfranc Injuries: A Systematic Review

BACKGROUND

There is a lack of consensus in the use of open reduction internal fixation (ORIF) vs primary arthrodesis (PA) in the management of Lisfranc injuries. Statistical fragility represents the number of events needed to flip statistical significance and provides context to interpret P values of outcomes from conflicting studies. The current study evaluates the statistical fragility of existing research with an outcome-specific approach to provide statistical clarity to the ORIF vs PA discussion. We hypothesized that statistical fragility analysis would offer clinically relevant insight when interpreting conflicting outcomes regarding ORIF vs PA management of Lisfranc injuries.

METHODS

All comparative studies, RCTs, and case-series investigating ORIF vs PA management of Lisfranc injuries published through October 5, 2023, were identified. Descriptive characteristics, dichotomous outcomes, and continuous outcomes were extracted. Fragility index and continuous fragility index were calculated by the number of event reversals needed to alter significance. Outcomes were categorized by clinical relevance, and median FI and CFI were reported.

RESULTS

A total of 244 studies were screened. Ten studies and 67 outcomes (44 dichotomous, 23 continuous) were included in the fragility analysis. Of the 10 studies, 4 studies claimed PA to correlate with superior outcomes compared to ORIF with regard to functional scores and return to function outcomes. Of these 4 studies, 3 were statistically robust. Six studies claimed PA and ORIF to have no differences in outcomes, in which only 2 studies were statistically robust.

CONCLUSION

The overall research regarding ORIF vs PA is relatively robust compared with other orthopaedic areas of controversy. Although the full statistical context of each article must be considered, studies supporting PA superiority with regard to functional scores and return to function metrics were found to be statistically robust. Outcome-specific analysis revealed moderate fragility in several clinically relevant outcomes such as functional score, return to function, and wound complications.

Fragile Statistical Findings in Randomized Controlled Trials Evaluating Autograft Versus Allograft Use in Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To analyze the statistical stability of randomized controlled trials (RCTs) evaluating the surgical management of autografts versus allografts in the anterior cruciate ligament reconstruction (ACLR) literature and calculate the fragility index (FI) and fragility quotient and explore a subgroup analysis by calculating the proportion of outcome events where the FI was less than the number of patients lost to follow-up.

METHODS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we conducted a systematic search in the PubMed and Cochrane databases to identify RCTs published between 2000 and 2022 that investigated the use of autografts versus allografts in ACLR literature and reported dichotomous data. The fragility index of each dichotomous variable was calculated through the reversal of a single outcome event until significance was reversed. The fragility quotient was calculated by dividing each fragility index by the study sample size. The interquartile range also was calculated.

RESULTS

Of the 4407 articles screened, 23 met the search criteria, with 11 RCTs evaluating ALCR using autografts and allografts included for analysis. Two hundred and 18 outcome events with 32 significant (P < .05) outcomes and 186 nonsignificant (P ≥ .05) outcomes were identified. The overall fragility index and fragility quotient for all 218 outcomes were 6 subjects (interquartile range 5-8) and 0.058 (interquartile range 0.039-0.077). Fragility analysis of statistically significant outcomes and nonsignificant outcomes had a fragility index of 3.5 (interquartile range 1-5.5) and 6 (interquartile range 5-8), respectively. All of the studies reported a loss to follow-up where 45.5% (5) reported a loss to follow-up greater or equal to 6.

CONCLUSIONS

The RCTs in the ACLR peer-reviewed literature evaluating autograft versus allograft use are vulnerable to a small number of outcome event reversals and exemplify significant statistical fragility in statistically significant findings.

LEVEL OF EVIDENCE

Level I, systematic review of Level I studies.

Editorial Commentary: The Statistical Fragility Index of Medical Trials Is Low By Design: Critical Evaluation of Confidence Intervals Is Required

The Fragility Index (FI) provides the number of patients whose outcome would need to have changed for the results of a clinical trial to no longer be statistically significant. Although it's a well-intended and easily interpreted metric, its calculation is based on reversing a significant finding and therefore its interpretation is only relevant in the domain of statistical significance. Its interpretation is only relevant in the domain of statistical significance. A well-designed clinical trial includes an a priori sample size calculation that aims to find the bare minimum of patients needed to obtain statistical significance. Such trials are fragile by design! Examining the robustness of clinical trials requires an estimation of uncertainty, rather than a misconstrued, dichotomous focus on statistical significance. Confidence intervals (CIs) provide a range of values that are compatible with a study's data and help determine the precision of results and the compatibility of the data with different hypotheses. The width of the CI speaks to the precision of the results, and the extent to which the values contained within have potential to be clinically important. Finally, one should not assume that a large FI indicates robust findings. Poorly executed trials are prone to bias, leading to large effects, and therefore, small P values, and a large FI. Let's move our future focus from the FI toward the CI.

Trends of Publications on Single- and Double-Bundle ACL Reconstructions over the Last 20 Years: A Bibliometric Analysis of the PubMed Literature

Purpose

To improve the clinical outcomes of anterior cruciate ligament reconstruction (ACLR), there have been attempts to reproduce anatomic reconstruction by modifying the single-bundle (SB) and double-bundle (DB) techniques. Although DB ACLR restores better rotational control compared to SB ACLR, it is still debatable whether there are higher clinical outcomes in favor of DB ACLR. We aimed to study the trends of publications on SB and DB ACLR techniques over the last 20 years.

Methods

For this bibliometric study, we performed a PubMed search on 31/05/2022 with a well-defined search strategy. The articles were downloaded into Excel software, and citations were determined from the iCite website for PubMed. The analysis was performed using SPSS software version 28.0.1. Data mining was performed using Orange software, Mac version 3.32.0, from the titles of all articles and each group of SB and DB ACLR. The output is presented as word clouds.

Results

A total of 10,530 publications were identified, of which 9699 publications (92.1%) pertained to SB-ACLR and 831 publications (7.9%) to DB-ACLR. There was a steady increase in the publications on SB-ACLR until 2012, followed by a steep increase that peaked in 2021. The highest number of publications on DB-ACLR was in 2012 (n = 76; 9.1%). The mean citations per year for SB-ACLR and DB-ACLR were 2.87 ± 4.31 and 2.74 ± 3.17, respectively. The most prolific journals publishing on this topic were Knee Surgery Sports Traumatology Arthroscopy, American Journal of Sports Medicine, and Arthroscopy. The top three articles that received the maximum number of citations were from Japanese authors.

Conclusion

The number of publications related to SB-ACLR was significantly higher than that related to DB-ACLR in the last 20 years. The publications related to DB-ACLR have decreased in the recent past, after reaching a peak in 2012. The citations per year of SB-ACLR and DB-ACLR were similar.

The Majority of Sports Medicine and Arthroscopy-Related Randomized Controlled Trials Reporting Nonsignificant Results Are Statistically Fragile

PURPOSE

To evaluate the robustness of sports medicine and arthroscopy related randomized controlled trials (RCTs) reporting nonsignificant results by calculating the reverse fragility index (RFI) and reverse fragility quotient (RFQ).

METHODS

All sports medicine and arthroscopic-related RCTs from January 1, 2010, through August 3, 2021, were identified. Randomized-controlled trials comparing dichotomous variables with a reported P value ≥ .05 were included. Study characteristics, such as publication year and sample size, as well as loss to follow-up and number of outcome events were recorded. The RFI at a threshold of P < .05 and respective RFQ were calculated for each study. Coefficients of determination were calculated to determine the relationships between RFI and the number of outcome events, sample size, and number of patients lost to follow-up. The number of RCTs in which the loss to follow-up was greater than the RFI was determined.

RESULTS

Fifty-four studies and 4,638 patients were included in this analysis. The mean sample size and loss to follow-up were 85.9 patients and 12.5 patients, respectively. The mean RFI was 3.7, signifying that a change of 3.7 events in one arm was needed to flip the results of the study from non-significant to significant (P < .05). Of the 54 studies investigated, 33 (61%) had a loss to follow-up greater than their calculated RFI. The mean RFQ was 0.05. A significant correlation between RFI with sample size (R2 = 0.10, P = .02) and the total number of observed events (R2 = 0.13, P < .01) was found. No significant correlation existed between RFI and loss to follow-up in the lesser arm (R2 = 0.01, P = .41).

CONCLUSIONS

The RFI and RFQ are statistical tools that allow the fragility of studies reporting nonsignificant results to be appraised. Using this methodology, we found that the majority of sports medicine and arthroscopy-related RCTs reporting nonsignificant results are fragile.

CLINICAL RELEVANCE

RFI and RFQ serve as tools that can be used to assess the validity of RCT results and provide additional context for appropriate conclusions.

Double-Versus Single-Bundle Anterior Cruciate Ligament Reconstructive Surgery: A Prospective Study With >1 Year Follow-Up

Background The increased prevalence of knee trauma predominantly adds to the anterior cruciate ligament (ACL) tear frequencies that require single- or double-bundle reconstructive surgeries. Few studies have demonstrated the superior results of double-bundle reconstruction compared to single-bundle approaches. This study investigated the knee function improvement capacity of both reconstruction techniques in patients with ACL tears. Methods Thirty cases with ACL tears have been enrolled and segregated equally in distinct (single-bundle versus double-bundle) batches. The diagnostic assessments were undertaken through comprehensive clinical history, knee radiographs, Lysholm scoring, the International Knee Documentation Committee (IKDC) scale, the Lachman analysis, the International Knee Documentation Committee (IKDC) scale, and the pivot shift method. Results After one year, there was a significant enhancement in the postoperative versus preoperative Lysholm scores in the single-bundle (58.5 ± 21.2 vs. 82.4 ± 26.2, p<0.001) and double-bundle (86.4 ± 22.8 vs 60.3 ± 19.2, p<0.001) groups. There was a significant improvement in the IKDC scores after a follow-up period of one year (p-value: 0.012 and p-value: 0.002, respectively) in both of the study batches. After a year of follow-up, Lysholm scores (p=0.352) and IKDC scores (p=0.574) between the study groups (82.4 ± 26.2 vs. 86.4 ± 22.8) were comparable. Conclusion The clinical outcomes remained comparable between subjects with single-bundle reconstruction versus double-bundle reconstruction subjects with ACL injuries. Findings were similar between the groups after one year and two years of surgical interventions.

The reverse fragility index: RCTs reporting non-significant differences in failure rates between hamstring and bone-patellar tendon-bone autografts have fragile results

PURPOSE

The reverse fragility index (RFI) is a novel metric to appraise the results of studies reporting statistically non-significant results. The purpose of this study was to determine the statistical robustness of randomized controlled trials (RCTs) reporting non-significant differences in anterior cruciate ligament reconstruction (ACLR) graft failure rates, defined as re-rupture/revision ACLR rate, between hamstring tendon (HT) and bone-patellar tendon-bone (BTB) autografts by calculating RFIs.

METHODS

A systematic review was performed to identify RCTs that compared HT to BTB grafts for ACLR through January 2022. Studies reporting non-significant differences in graft re-rupture and revision ACLR rate (n.s.) were included. The RFI, defined as the fewest number of event reversals needed to change the non-significant graft re-rupture/revision outcome to statistically significant (P < 0.05), was recorded for each study. In addition, the number of studies in which the loss to follow-up exceeded the RFI was recorded.

RESULTS

Among the 16 included RCTs, the median (interquartile range [IQR]) sample size was 71 (64-114), and the median (IQR) total number of graft re-rupture/revision ACLR events was 4 (4-6). The median (IQR) graft re-rupture/revision ACLR rate was 4.3% (3.0-6.4) overall, 4.1% (2.6-6.7) in the BTB group, and 5.4% (3.0-6.3) in the HT group. The median (IQR) RFI was 3 (3-4), signifying that a reversal of the outcome in 3 patients in one arm was needed to flip the studies' result from non-significant to statistically significant (P < 0.05). The median (IQR) number of participants lost to follow-up was 11 (3-13), and 13 (81.3%) of the included studies had a loss to follow-up greater than the studies' RFI.

CONCLUSION

The results of RCTs reporting statistically non-significant re-rupture/revision ACLR rates between HT and BTB autografts would become significant if the outcome were reversed in a small number of patients-a number that was less than the loss to follow-up in the majority of studies. Thus, the neutrality of these studies is fragile, and a true statistically significant difference in re-rupture/revision rates may have been undetected.

LEVEL OF EVIDENCE

Level I.

The Statistical Fragility of Operative vs Nonoperative Management for Achilles Tendon Rupture: A Systematic Review of Comparative Studies

BACKGROUND

The statistical significance of randomized controlled trials (RCTs) and comparative studies is often conveyed utilizing the P value. However, P values are an imperfect measure and may be vulnerable to a small number of outcome reversals to alter statistical significance. The interpretation of the statistical strength of these studies may be aided by the inclusion of a Fragility Index (FI) and Fragility Quotient (FQ). This study examines the statistical stability of studies comparing operative vs nonoperative management for Achilles tendon rupture.

METHODS

A systematic search was performed of 10 orthopaedic journals between 2000 and 2021 for comparative studies focusing on management of Achilles tendon rupture reporting dichotomous outcome measures. FI for each outcome was determined by the number of event reversals necessary to alter significance (P < .05). FQ was calculated by dividing the FI by the respective sample size. Additional subgroup analyses were performed.

RESULTS

Of 8020 studies screened, 1062 met initial search criteria with 17 comparative studies ultimately included for analysis, 10 of which were RCTs. A total of 40 outcomes were examined. Overall, the median FI was 2.5 (interquartile range [IQR] 2-4), the mean FI was 2.90 (±1.58), the median FQ was 0.032 (IQR 0.012-0.069), and the mean FQ was 0.049 (±0.062). The FI was less than the number of patients lost to follow-up for 78% of outcomes.

CONCLUSION

Studies examining the efficacy of operative vs nonoperative management of Achilles tendon rupture may not be as statistically stable as previously thought. The average number of outcome reversals needed to alter the significance of a given study was 2.90. Future analyses may benefit from the inclusion of a fragility index and a fragility quotient in their statistical analyses.