A prospective randomized comparison of two distinct allogenic tissue constructs for anterior cruciate ligament reconstruction

Various Definitions of Failure Are Used in Studies of Patients Who Underwent Anterior Cruciate Ligament Reconstruction

Purpose

To conduct a literature review to assess the definitions of anterior cruciate ligament reconstruction (ACLR) failure used throughout the orthopaedic literature.

Methods

A systematic search of Embase, Ovid Medline, SPORTDiscus, and Web of Science was conducted by a university librarian to identity level I-IV clinical studies on ACLR failure. Inclusion criteria consisted of patients who underwent ACLR and included a definition of failure of ACLR. Patients who underwent anterior cruciate ligament (ACL) repairs, animal/cadaver studies, review studies, non-English language articles, and non-full text articles were excluded. Failure data were extracted from each study and categorized. Other data that were extracted included follow-up time after ACLR, failure reoperation rate, and failure reoperation procedure. Descriptive statistics was used to analyze the data.

Results

Out of 2,775 studies, 104 (3.75%) met inclusion criteria and were analyzed in this review. The most common definition of ACLR failure included the use of a physical examination, specifically Lachman's test (21/104 [20.2%]), anterior laxity assessment, or a Pivot-Shift test (24/104 [35.2%]) or undergoing or requiring revision ACLR (39/104 [37.5%]). Although some studies used quantitative tests or imaging to help define "failure," others simply defined it as graft rerupture that was otherwise not defined (22/104 [22.5%]). Other common definitions included: the use of imaging (magnetic resonance imaging/radiographs) to confirm graft re-rupture (37/104 [35.6%]), patient-reported outcomes (recurrent instability)/patient reported outcomes measures (International Knee Documentation Committee [IKDC], Knee injury and Osteoarthritis Outcome Score [KOOS], Tegner) (18/104 [17.3%]), and the use of an arthrometer (KT-1000/2000, Rollimeter, or Kneelax) (17/104 [16.3%]). The least common definitions included graft failure or rerupture confirmed by arthroscopy (13/104 [12.5%]) and nonrevision surgery (2/104 [1.0%]). The failure rate of this procedure ranged from 0% to 100% depending on the definition of "failure."

Conclusion

In this study, we found that a variety of definitions of failure are used among studies published in the orthopaedic literature. The most common criteria for failure of ACLR were the results of physical examination tests (35%), the need for undergoing a revision ACLR (36%), and the use of imaging to diagnose the failure (34%). About 17% of studies included in this review used patient-reported outcomes, specifically recurrent instability, or PROMs (IKDC, KOOS, Tegner) in their assessment of failure of ACLR. The least used definitions of "failure" of ACLR included nonrevision ACLR surgery (2%). Although some studies used similar tests or categories in their definition of failure, there were a variety of score and grade cutoff points between them.

Level of Evidence

Level IV, systematic review of Level II-IV studies.

Return to Sports: A Risky Business? A Systematic Review with Meta-Analysis of Risk Factors for Graft Rupture Following ACL Reconstruction

BACKGROUND

The risk of sustaining a graft rupture after anterior cruciate ligament reconstruction (ACLR) is high. Contributing risk factors are, however, still not clearly identified.

OBJECTIVE

The aim of this systematic review was to identify and quantify risk factors for graft rupture after ACLR.

METHODS

A systematic review with meta-analysis (PROSPERO CRD42020140129) based on PRISMA guidelines was performed. MEDLINE, CINAHL and EMBASE were searched from inception to September 2021. Prospective and retrospective studies addressing risk factors for graft rupture after ACLR in males/females of all ages were considered. Meta-analyses using a random effect model (effect measure: odds ratio [OR] with 95% confidence interval [CI]) were performed. The GRADE tool was used to assess evidence quality.

RESULTS

Following full-text screening of 310 relevant papers, 117 were eventually included, incorporating up to 133,000 individuals in each meta-analysis. Higher Tegner activity level (≥ 7 vs < 7) at primary injury (OR 3.91, 95% CI 1.69-9.04), increased tibial slope (degrees) (OR 2.21, 95% CI 1.26-3.86), lower psychological readiness to return to sport (RTS) (OR 2.18, 95% CI 1.32-3.61), early surgery (< 12 vs ≥ 12 months) (OR 1.87, 95% CI 1.58-2.22), RTS (pre-injury level) (OR 1.87, 95% CI 1.21-2.91) and family history of ACL injury (OR 1.76, 95% CI 1.34-2.31) were all associated with increased odds of graft rupture. Higher age (OR 0.47, 95% CI 0.39-0.59), female sex (OR 0.88, 95% CI 0.79-0.98), fewer self-reported knee symptoms pre-reconstruction (OR 0.81, 95% CI 0.69-0.95) and concomitant cartilage injuries (OR 0.70, 95% CI 0.62-0.79) instead decreased the odds. Meta-analysis revealed no association between body mass index, smoking, joint laxity, RTS time, knee kinematics, muscle strength or hop performance and graft rupture.

CONCLUSION

Conspicuous risk factors for graft rupture were mainly sports and hereditary related. Few studies investigated function-related modifiable factors or included sports exposure data.

Are PROMs used adequately in sports research? An analysis of 54 randomized controlled trials with PROMs as endpoint

Deviations from adequate use and reporting of PROMs may be problematic and misleading. The aim of this study was to investigate the extent of such problems in randomized clinical trials (RCTs). RCTs involving sports medicine research that used PROMs as primary outcomes were identified in 13 preselected journals. The articles were reviewed for nine potential problems related to how the PROM was used and how the data had been reported. The potential problems were as follows: aggregating subscale scores; combining patient-reported scores with physical, clinical, or para-clinical measures; using a PROM to diagnose or evaluate the individual patient; using a PROM for one leg or arm; selectively excluding domains or items; constructing a PROM for the specific occasion; mixing PROM formats (ie, digital, paper, telephone, e-mail, in person); ambiguous instructions for how the PROM should be completed; and recall bias. As covariates, we registered journal impact factor, year of publication, and existence of a registered protocol. In 29 (53.7%) of 54 identified RCTs, at least one potential problem was identified, the most common being aggregation of domain scores. This was not different with a published protocol or dependent on journal rankings, except for exclusion of domains, which was most common in high-ranking journals. Aggregation of domain scores was significantly less common in recently published articles compared with older articles (P = .03). Potential problematic use of PROMs and reporting of PROM data are common in RCTs, also in high-ranking journals, but less so in more recent articles.

Allograft for knee ligament surgery: an American perspective

PURPOSE

Allografts are frequently use for ligamentous reconstruction at the knee. In the United States, tissue donation and distribution are highly regulated processes with thorough oversight from private and government entities. Allograft is widely available in the United States and allograft procurement is a large industry with varying procurement, sterilization, processing, and distribution procedures. It is important to understand allograft regulation and processing which may affect graft mechanical properties and biological graft integration.

METHODS

English-language literature, United States government and regulatory agency statues pertaining to allograft procurement, distribution, and usage were reviewed and the findings summarized.

RESULTS

During the processing of allograft, multiple factors including sterilization procedures, irradiation, storage conditions, and graft type all affect the biomechanical properties of the allograft tissue. Biological incorporation and ligamentization of allograft does occur, but at a slower rate compared with autograft. For ligamentous reconstruction around the knee, allograft offers shorter operative time, no donor-site morbidity, but has shown an increased risk for graft failure compared to autograft.

CONCLUSION

This article reviews the regulations on graft tissue within the United States, factors affecting the biomechanics of allograft tissue, differences in allograft tissue choices, and the use of allograft for anterior cruciate ligament reconstruction and multiligamentous knee injury reconstruction.

LEVEL OF EVIDENCE

V.

The use of allograft tendons in primary ACL reconstruction

PURPOSE

Graft choice in primary anterior cruciate ligament (ACL) reconstruction remains controversial. The use of allograft has risen exponentially in recent years with the attraction of absent donor site morbidity, reduced surgical time and reliable graft size. However, the published evidence examining their clinical effectiveness over autograft tendons has been unclear. The aim of this paper is to provide a current review of the clinical evidence available to help guide surgeons through the decision-making process for the use of allografts in primary ACL reconstruction.

METHODS

The literature in relation to allograft healing, storage, sterilisation, differences in surgical technique and rehabilitation have been reviewed in addition to recent comparative studies and all clinical systematic reviews and meta-analyses.

RESULTS

Early reviews have indicated a higher risk of failure with allografts due to association with irradiation for sterilisation and where rehabilitation programs and post-operative loading may ignore the slower incorporation of allografts. More recent analysis indicates a similar low failure rate for allograft and autograft methods of reconstruction when using non-irradiated allografts that have not undergone chemically processing and where rehabilitation has been slower. However, inferior outcomes with allografts have been reported in young (< 25 years) highly active patients, and also when irradiated or chemically processed grafts are used.

CONCLUSION

When considering use of allografts in primary ACL reconstruction, use of irradiation, chemical processing and rehabilitation programs suited to autograft are important negative factors. Allografts, when used for primary ACL reconstruction, should be fresh frozen and non-irradiated. Quantification of the risk of use of allograft in the young requires further evaluation.

LEVELS OF EVIDENCE

III.

Comparison of freeze-dried tibialis anterior allograft and four-strand hamstring autograft in anterior cruciate ligament reconstruction

PURPOSE

The aim of this retrospective study was to evaluate the clinical outcomes of the patients who underwent primary anterior cruciate ligament (ACL) reconstruction surgery with either hamstring autograft or freeze-dried tibialis anterior allograft, which performed by the same surgeon using the same fixation technique.

METHODS

In this retrospective study, patients who had primary ACL reconstruction using either four-strand hamstring autograft (FSH) or freeze-dried irradiated tibialis anterior allograft (FDT) between 2012 and 2015 were evaluated. Patients who were skeletally mature with a minimum follow-up of 24 months and who had no previous surgery from the affected knee were included; patients who had multiple ligament injuries or chondral lesions over Outerbridge grade 2 were excluded from the study. Patients were grouped according to the graft type used in ACL reconstruction. Tegner activity scale and Lysholm knee scoring scale were used to assess patients' activity levels and functional status preoperatively and at the final follow-up. KT-2000 arthrometer measurements were done at the final follow-up to evaluate anterior laxity.

RESULTS

There were 27 patients (mean age 27 ± 8.9 years) in the FSH group and 36 patients (mean age 27.1 ± 6.7 years) in the FDT group. The mean follow-up time was 38.2 ± 3.5 months for the FSH group and 41 ± 6.1 months for the FDT group. There were no statistically significant differences between the groups when preoperative and postoperative Tegner-Lysholm scores were compared (Tegner P = 0.583, 0.742; Lysholm P = 0.592, 0.249). The mean anteroposterior laxity and side-to-side differences measured by KT-2000 were 4.1 mm and 2.1 mm for the FSH group, respectively; 4.2 mm and 2.2 mm for the FDT group, respectively. There was not a statistically significant difference (P = 0.745, 0.562 respectively).

CONCLUSIONS

Primary ACL reconstruction with a single loop freeze-dried irradiated tibialis anterior allograft revealed comparable results with four-strand hamstring autograft in non-athlete patients.

LEVEL OF EVIDENCE

Level III, Therapeutic study.

Allograft Maturation After Reconstruction of the Anterior Cruciate Ligament Is Dependent on Graft Parameters in the Sagittal Plane

Background:

Allograft healing (ligamentization) after reconstruction of the anterior cruciate ligament (ACL) is dependent on multiple factors, including tissue processing, host biologic environment, and biomechanical stressors. Magnetic resonance imaging (MRI) can be used to assess graft maturation after ACL reconstruction.

Hypothesis:

A significant difference will exist in the MRI analysis between 2 distinct allograft constructs. Specifically, the MRI signal-to-noise quotient (SNQ) value will be smaller in quadrupled hamstring tendon (HT) allografts compared with doubled tibialis anterior (TA) allografts due to the difference in graft geometry (surface area–to-volume ratio).

Study Design:

Cohort study; Level of evidence, 2.

Methods:

Prospectively collected data from a subset of patients who participated in a randomized controlled trial at a single center from July 2010 to April 2012 were reviewed. Patients underwent ACL reconstruction using either HT or TA allografts. Six months postoperatively, 32 patients underwent noncontrast MRI to assess ligamentization. The SNQ was calculated for the allograft using sagittal noncontrast T2-weighted MRI as follows: SNQ = (S_graft − S_qaudriceps)/S_backgroud. Graft properties including sagittal and coronal angle as well as tibial and femoral tunnel location were measured. All participants completed validated patient-reported outcome measures preoperatively and at 2 years postoperatively.

Results:

The mean MRI SNQ for the HT and TA allografts was 2.56 ± 2.41 and 3.15 ± 3.38, respectively (P = .57). For the entire group, there was a significant correlation between MRI SNQ and both sagittal graft angle (P = .02) and sagittal tibial tunnel position (P < .001). We did not find a significant correlation between the tibial tunnel location in the coronal plane, coronal graft angle, or location of the femoral tunnel and the MRI SNQ.

Conclusion:

Allograft ligamentization 6 months postoperatively, as assessed by MRI, is dependent on position of the tibial tunnel in the sagittal plane as well as sagittal graft orientation. We did not detect a difference in graft maturation at 6 months between the tibialis anterior and hamstring tendon allografts. This is the only study to our knowledge that directly compares quadrupled HT allografts and doubled TA allografts using postoperative MRI.