Abstract
Background:
Anterior cruciate ligament (ACL) repair had previously been considered the standard of care for a ruptured ACL; however, ACL reconstruction has became the standard of care because of poor midterm outcomes after ACL repair. Recently, studies have suggested that the treatment paradigm should shift back to ACL repair.
Purpose/Hypothesis:
The purpose of this study was to evaluate the outcomes of ACL repair augmented with suture tape in a high-demand military population. We hypothesized that for proximal ACL avulsions, ACL repair with suture tape augmentation would lead to acceptable failure rates, satisfactory knee stability, excellent functional outcomes, and high rates of return to preinjury activity levels.
Study Design:
Case series; Level of evidence, 2.
Methods:
Patients who were treated with ACL repair by a single surgeon between March 2017 and June 2019 and who had a minimum of 2 years of follow-up were included. Intraoperatively, all patients first underwent an arthroscopic examination. If an ACL avulsion of the proximal insertion with adequate remaining tissue was visualized, then ACL repair was performed. The primary outcome assessed was ACL repair failure, defined as reruptures or clinical instability requiring revision to ACL reconstruction. Analysis of the risk factors for ACL repair failure was conducted, with age at surgery, sex, body mass index, level of competition, and tobacco use evaluated.
Results:
Included were 46 patients (32 male and 14 female; mean age, 28.3 ± 8.4 years) who underwent ACL repair with suture tape augmentation. There were 12 cases of failure (26.1%; 8 male and 4 female). The mean time from injury to surgery in the failure group was 164.1 ± 59.4 days compared to 107.3 ± 98.0 days in the nonfailure group (P = .02). According to multivariate regression analysis, patients aged ≤17 and ≥35 years, elite/competitive/operational patients, and current smokers had a higher chance of ACL repair failure. The mean time to pass a military physical fitness test was 5.0 months. There were no complications other than ACL repair failure.
Conclusion:
Primary arthroscopic ACL repair with suture tape augmentation resulted in unacceptably high failure rates at a minimum of 2 years of follow-up in a highly active military population. Age ≤17 and ≥35 years, elite level of competition, time from injury to surgery, and active tobacco use were independent risk factors for ACL repair failure.
Keywords: anterior cruciate ligament, repair, failure rates, risk factors, military
Historically, primary repair of the anterior cruciate ligament (ACL) has been found to have poor clinical outcomes. 1,9,33 The results of a seminal study of ACL repair on West Point cadets by Feagin and Curl 10 found an unacceptably high rate of reruptures and subjective instability. Of note, however, these repair procedures were all performed before the advent of arthroscopic surgery and without the advantage of magnetic resonance imaging. Subsequently, the standard of care for the surgical treatment of an ACL rupture has become ACL reconstruction (ACLR) using either autograft or allograft tissue. 25,29,34 Recently, the concept of ACL repair in very limited cases has been revisited. Proponents of ACL repair have suggested that, in select cases, repair of a proximally ruptured ACL may be more preferable than reconstruction. 2 Several studies have shown that, in proximal ACL tears, repair may be considered because of the adequate healing potential of the native ligament. 30 Proposed advantages of ACL repair include the preservation of native proprioception and vascularity through innervation and blood supply of the native ligament. Additional potential benefits of repair are smaller incisions, the obviation of graft site morbidity, and a quicker return to function. 5,7,8,22,24
Recently, several studies have investigated the clinical outcomes of ACL repair. 15,20,35 One factor that has been specifically addressed in several studies is the use of strong nonabsorbable suture tape to protect the ACL repair site during the early phase of healing. Jonkergouw et al 22 reported a 10.7% failure rate of ACL repair at an minimum 2-year follow-up. In a similar study, Heusdens et al 17 reported a 4.8% failure rate in 48 patients who underwent ACL repair with suture tape augmentation. Lastly, van der List et al, 36 in a meta-analysis, reported on arthroscopic ACL repair techniques, with failure rates of 7% to 11%, no complications, and functional outcome scores of >85% of the maximum.
The purpose of this study was to evaluate the outcomes of ACL repair augmented with suture tape in a high-demand military population. We hypothesized that for proximal ACL avulsions, ACL repair with suture tape augmentation would lead to acceptable failure rates, satisfactory knee stability, excellent functional outcomes, and high rates of return to preinjury activity levels.
Methods
Between March 2017 and June 2019, a total of 196 ACL ruptures were managed operatively by the senior author (C.R.B.). Of these cases, 144 ACLR and 52 ACL repair procedures were performed. All patients with an ACL rupture who were indicated for operative management consented to undergo both ACL repair and ACLR. Indications for ACL repair included a proximal lateral femoral condyle avulsion with adequate remaining native ACL tissue. We excluded patients who chose ACLR as well as those with multiligamentous knee injuries and those who had not completed 2-year follow-up at the time of data collection.
Initially included in this study were 52 consecutive patients treated with ACL repair between March 2017 and June 2019. Overall, 6 patients were lost to follow-up, leaving 46 patients available for analysis at a minimum 2-year follow-up. This study was considered exempt from institutional review board approval by our institution. All study patients provided informed consent.
Surgical Procedure
All ACL repair procedures and arthroscopic evaluations were performed at a single institution by the senior author (C.R.B.), who is board certified and fellowship trained in sports medicine. All patients first underwent an examination under anesthesia to confirm pathological laxity of the ACL and a subsequent arthroscopic examination to confirm the ligament injury. Most importantly, to ascertain the feasibility of ACL repair, the location of the rupture and the quality of remaining tissue were carefully examined (Figure 1).
Figure 1.
Proximal anterior cruciate ligament avulsion with adequate good-quality remaining tissue.
If a proximal ACL avulsion from the medial wall of the lateral femoral condyle was identified during initial arthroscopic surgery, the remaining ACL tissue was thoroughly inspected. If it was determined that the quality of the native ACL was adequate, then ACL repair was performed. To help mitigate suture entanglement and facilitate instrument passage, a large flexible cannula was inserted into the anteromedial portal (10-mm PassPort Cannula; Arthrex). The ligament was sutured using a self-retrieving suture-passing instrument (Scorpion; Arthrex) loaded with a high-strength nonabsorbable suture (No. 2 FiberWire; Arthrex) in an interlocking-loop fashion starting from the distal aspect (tibial insertion) and working proximally (Figure 2).
Figure 2.
(A) A Scorpion suture passer (Arthrex) was used to pass the suture through the anterior cruciate ligament (ACL). (B) The ACL was sutured with an interlocking-loop technique.
The femoral footprint on the medial wall of the lateral femoral condyle was abraded with an arthroscopic shaver to stimulate a healing response and to clearly identify the femoral footprint for repair (Figure 3A). A suture anchor (4.75-mm BioComposite SwiveLock; Arthrex) was preloaded with high-strength suture tape (FiberTape; Arthrex) as well as the free ends of the suture that was passed through the native ACL (Figure 3B). A standard ACL tibial drill guide was utilized to pass a drill-tip pin to the base of the ACL tibial footprint, taking care not to damage the previously placed sutures. Over this guide pin, a 4.5-mm cannulated reamer was used to create a tunnel, after which the reamer was left in place and the guide pin removed. Through the cannulated reamer, a nitinol wire with a looped end was passed into the joint and retrieved out the anteromedial portal. The free ends of the suture tape were then shuttled into the joint and down the tibial drill hole with the nitinol wire. The ligament was then reapproximated to the anatomic femoral footprint using the suture anchor. Next, the ends of the suture tape were tensioned and secured to the tibia using an additional suture anchor (4.75-mm BioComposite SwiveLock, Arthrex) while the knee was placed in full extension (Figure 3C).
Figure 3.
(A) A SwiveLock punch (Arthrex) was used in the native anterior cruciate ligament (ACL) insertion on the lateral femoral condyle after the femoral condyle was abraded with an arthroscopic shaver. (B) A SwiveLock anchor (Arthrex) containing the sutures placed in the ACL preloaded with high-strength suture tape (FiberTape; Arthrex) was inserted for internal brace augmentation. (C) Final ACL repair construct with suture tape augmentation.
Postoperative Management
Patients without concomitant meniscal repair were immediately permitted to be weightbearing as tolerated with a hinged knee brace locked in extension for the first 2 weeks. While in a nonweightbearing status, these patients were permitted knee range of motion as tolerated. For the following 4 weeks, patients continued to wear their hinged knee brace; however, they were allowed to have full range of motion with the use of a crutch for ambulation. If meniscal repair was performed, the postoperative regimen was altered accordingly: the patients were nonweightbearing, and range of motion was restricted to 90° of flexion for 4 weeks postoperatively. All patients followed a standardized ACLR rehabilitation protocol supervised by a physical therapist. 21 Full active motion was encouraged in all cases. The hinged knee brace was typically discontinued at 4 weeks postoperatively. Patients were allowed to return to sport or military activity when cleared by their physical therapist at a minimum of 4 months postoperatively.
Evaluation at Latest Follow-up
Study patients were contacted by telephone to complete a survey to ascertain if they had sustained any injury that necessitated revision ACL surgery or if they had any subjective knee instability. Patients were queried as to whether they were able to remain on active-duty status after ACL repair. Additionally, if they remained on active duty, they were asked when they were able to pass a military physical fitness test after their ACL surgery. Online questionnaires were administered via email to assess functional outcomes. Patients completed the Knee injury and Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee (IKDC) questionnaires as well as the Single Assessment Numeric Evaluation (SANE). Patient-reported outcomes from those who sustained ACL repair failure were excluded. Knee stability was assessed by asking patients if they had subjective stability with sports or daily activities. Postoperative complications were assessed via a chart review and telephone questionnaire.
Statistical Analysis
Descriptive statistical analysis were performed using Excel (Microsoft) for ACL repair failure requiring revision surgery; KOOS, IKDC, and SANE scores; postoperative subjective instability; return to full active-duty status; and time to pass a military physical fitness test. The primary outcome was ACL repair failure requiring revision surgery.
Analysis of the risk factors for ACL repair failure was conducted based on age at surgery (3 comparison groups), sex, body mass index, level of competition (2 comparison groups), and tobacco use (never vs former vs current; current [yes vs no]). Age comparisons were as follows: (1) 12-17 versus 18-27 versus 28-34 versus 35-50 years, (2) 18-27 versus ≤17 or ≥28 years, and (3) 18-34 versus ≤17 or ≥35 years. Comparisons of level of competition were as follows: (1) recreational versus competitive/operational versus elite and (2) recreational versus competitive/elite/operational. “Operational” is a military special forces activity designation. The analysis of risk factors was performed using the Fisher exact test if there were 2 levels and the chi-square test if there were >2 levels. In addition, multivariate logistic regression analysis was performed for risk factors associated with ACL repair failure, with variables of interest being age at surgery, body mass index, sex, level of competition, tobacco use, and time from injury to surgery. Significance was assumed for P values <.05. Statistical analysis was conducted using SPSS version 18.0 statistical software (IBM).
A post hoc power analysis was performed with the variable of interest being the failure rate. Based on an effect size of 0.5 and an alpha value of 0.8, a minimum of 91 patients per study group was required to achieve a power of 0.8.
Results
All 46 study patients (32 male and 14 female) were active-duty service members at the time of their index procedure. The mean time from injury to surgery was 96.8 ± 77.4 days. Patient characteristics are shown in Table 1. Concomitant intra-articular abnormalities including medial meniscal tears, lateral meniscal tears, tears requiring repair, medial femoral condyle chondromalacia, lateral femoral condyle chondromalacia, and patellofemoral chondromalacia for all patients are shown in Table 2.
Table 1.
Patient Demographics (n = 46) a
| Variable | Value | Variable | Value b |
|---|---|---|---|
| Age | Competition level | ||
| 12-17 y | 6 (13.0) | Recreational | 27 (64.3) |
| 18-27 y | 16 (34.8) | Competitive/operational | 5 (11.9) |
| 28-34 y | 14 (30.4) | Elite | 10 (23.8) |
| 35-50 y | 10 (21.7) | Tobacco use | |
| Mean ± SD, y | 28.3 ± 8.4 | Never | 37 (80.4) |
| Median (IQR), y | 28.5 (23-34) | Former | 2 (4.3) |
| Sex | Yes (cigarettes) | 4 (8.7) | |
| Female | 14 (30.4) | Yes (e-cigarettes) | 2 (4.3) |
| Male | 32 (69.6) | Yes (chewing tobacco) | 1 (2.2) |
| Body mass index | Current tobacco use | ||
| <25 kg/m2 | 6 (13.3) b | No | 39 (84.8) |
| 25-29 kg/m2 | 25 (55.6) | Yes | 7 (15.2) |
| ≥30 kg/m2 | 14 (31.1) |
a Data are reported as n (%) unless otherwise indicated. IQR, interquartile range.
b 46 is the total number of patients included in follow-up for the study. Not all patients met the competition level.
Table 2.
Concomitant Intra-articular Abnormalities a
| Failure (n = 12) | Nonfailure (n = 34) | |
|---|---|---|
| Medial meniscal tear | 0 (0.0) | 6 (13.0) |
| Lateral meniscal tear | 3 (37.5) | 20 (43.5) |
| Tears requiring repair | 0 (0.0) | 5 (10.9) |
| Patellofemoral chondromalacia | 1 (12.5) | 4 (8.7) |
| Medial femoral condyle chondromalacia | 0 (0.0) | 3 (6.5) |
| Lateral femoral condyle chondromalacia | 2 (25.0) | 4 (8.7) |
a Data are reported as n (%).
At a mean follow-up of 3.1 ± 1.1 years, there were 12 cases of failure (26.1%) defined as reruptures or clinical instability requiring conversion to ACLR. Of the patients with failures, 8 were male (66.7%), and 4 were female (33.3%) (P > .99). Of these, 3 failures (25.0%) were a result of chronic residual instability without a traumatic reinjury. The mean time from injury to surgery in the failure group was 164.1 ± 59.4 days compared to 107.3 ± 98.0 days in the nonfailure group (P = .02). Patients aged ≥35 years had a failure rate of 50.0% compared to 12.5% in patients aged 18-27 years and 21.4% in patients aged 28-34 years. Additionally, there was a 33.3% failure rate in patients aged 12-17 years (Table 3).
Table 3.
Failure Rates (n = 12) a
| Total No. of Patients | n (%) | P Value | |
|---|---|---|---|
| Age (grouping 1) | .186 | ||
| 12-17 y | 6 | 2 (33.3) | |
| 18-27 y | 16 | 2 (12.5) | |
| 28-34 y | 14 | 3 (21.4) | |
| 35-50 y | 10 | 5 (50.0) | |
| Age (grouping 2) | .170 | ||
| 18-27 y | 16 | 2 (12.5) | |
| ≤17 or ≥28 y | 30 | 10 (33.3) | |
| Age (grouping 3) | .077 | ||
| 18-34 y | 30 | 5 (16.7) | |
| ≤17 or ≥35 y | 16 | 7 (43.8) | |
| Sex | >.999 | ||
| Female | 14 | 4 (28.6) | |
| Male | 32 | 8 (25.0) | |
| Body mass indexb | .881 | ||
| <25 kg/m2 | 6 | 2 (33.3) | |
| 25-29 kg/m2 | 25 | 6 (24.0) | |
| ≥30 kg/m2 | 14 | 4 (28.6) | |
| Competition level (grouping 1)b | .032 | ||
| Recreational | 27 | 3 (11.1) | |
| Competitive/operational | 5 | 2 (40.0) | |
| Elite | 10 | 5 (50.0) | |
| Competition level (grouping 2)b | .020 | ||
| Recreational | 27 | 3 (11.1) | |
| Competitive/elite/operational | 15 | 7 (46.7) | |
| Tobacco use | — c | ||
| Never | 37 | 8 (21.6) | |
| Former | 2 | 0 (0.0) | |
| Yes (cigarettes) | 4 | 2 (50.0) | |
| Yes (e-cigarettes) | 2 | 1 (50.0) | |
| Yes (chewing tobacco) | 1 | 1 (100.0) | |
| Current tobacco use | .064 | ||
| No | 39 | 8 (20.5) | |
| Yes | 7 | 4 (57.1) |
a Boldface P values indicate a statistically significant difference between groups (P < .05).
b 46 is the total number of patients included in follow-up for the study. Not all patients met the competition level.
c The model was not run for this variable.
There was a significantly higher failure rate in patients identified as elite athletes compared to competitive and/or recreational athletes (P = .020) (Table 3). Multivariate logistic regression analysis indicated a significantly higher failure rate in patients aged ≤17 years or ≥35 years (P = .049). Tobacco use was identified as a risk factor for failure, with a higher failure rate in smokers compared to nonsmokers (P = .035) (Table 4).
Table 4.
Multivariate Logistic Regression Analysis of ACL Repair Failure a
| Odds Ratio (95% CI) | P Value | |
|---|---|---|
| Age (grouping 1) | ||
| 18-27 y | 1.00 (reference) | — |
| 12-17 y | 8.67 (0.58-130.00) | .118 |
| 28-34 y | 3.55 (0.32-39.10) | .302 |
| 35-50 y | 10.40 (0.92-117.00) | .058 |
| Age (grouping 2) | ||
| 18-27 y | 1.00 (reference) | — |
| ≤17 or ≥28 y | 6.16 (0.69-54.60) | .103 |
| Age (grouping 3) | ||
| 18-34 y | 1.00 (reference) | — |
| ≤17 or ≥35 y | 4.50 (1.01-20.10) | .049 |
| Competition level | ||
| Recreational | 1.00 (reference) | — |
| Elite/competitive/operational | 7.00 (1.45-33.69) | .015 |
| Current tobacco use | ||
| No | 1.00 (reference) | — |
| Yes | 6.44 (1.14-36.60) | .035 |
a Boldface P values indicate a statistically significant difference. ACL, anterior cruciate ligament.
At a minimum 2-year follow-up, of the nonfailure group (n = 34), 83.7% of patients reported subjective stability with cutting and pivoting activities. Additionally, of the nonfailure group, the mean IKDC score was 81.2 ± 8.8, the mean KOOS score was 83.7 ± 8.4, and the mean SANE score was 82.9 ± 9.3. There were 6 patients (13.0%) who were not able to return to full active-duty status without restrictions. The mean time from surgery to clearance by a physical therapist and the ability to pass a military physical fitness test was 5.0 months. There were no other complications other than ACL repair failure.
Discussion
The results of this study demonstrated poor short-term failure rates after ACL repair with suture tape augmentation in an active-duty military population. The overall failure rate in this active-duty military population was 26.1%. Additionally, of the nonfailure group, only 83.7% reported subjective stability with cutting and pivoting activities.
In contrast to our study results, recent literature has demonstrated improved clinical outcomes as well as lower rerupture rates with modern ACL repair techniques. § In a prospective randomized controlled trial comparing ACL repair to ACLR, Hoogeslag et al 19 found that augmented ACL suture repair was not inferior to ACLR in terms of subjective patient-reported outcomes and rerupture rates at 2-year follow-up. Furthermore, Jonkergouw et al 22 reported that 88.9% of patients who underwent ACL repair had stable knees. They also reported a rerupture rate of 10.7% with excellent subjective outcomes in 89.3% of patients at 3.2-year follow-up. Lastly, Heusdens et al 18 reported excellent outcomes after ACL repair with suture tape augmentation with a 4.8% failure rate in 42 patients at 2-year follow-up.
Gagliardi et al 13 reported a 48.8% failure rate after ACL repair in 22 adolescents at 3-year follow-up. These results were more similar to the findings of our study. Additionally, we found poor results in subjective stability during cutting and pivoting activities, with only 83.7% reporting subjective stability. Our results may be explained by the demands of active-duty service members. Similar to high-level athletes, military personnel are under time constraints to return to duty. An important finding from this study was the ability of patients who underwent ACL repair to be cleared by a physical therapist and be able to pass a military physical fitness test at a mean of 5.0 months. Clearance by a physical therapist was determined by a standardized protocol. 21 Traditionally, ACLR has been associated with quadriceps weakness and knee stiffness. 3 Additionally, graft harvest is associated with significant morbidity including kneeling pain for those with bone–patellar tendon–bone autografts and hamstring weakness for those with hamstring tendon autografts. 6 A benefit of ACL repair includes the potential preservation of proprioception of the native ligament. 11,24,27 However, given the lack of morbidity associated with graft harvest and the maintenance of native proprioception, patients may feel ready to return to sport before the repair site has completely healed. In this study, the mean time to return to duty of 5.0 months may be too soon to allow adequate healing of ACL repair. Further investigation is required to determine the appropriate time to return to sport after ACL repair.
However, in the nonfailure group, patients demonstrated good to excellent functional outcome scores. Similarly, Gagliardi et al 13 reported good functional outcome scores in patients who did not sustain a failure. Our study patients were able to return to duty at a mean of 5.0 months. This finding corroborates the proposed benefits of ACL repair: lack of donor site morbidity and improved proprioception. We do believe that this demonstrates a select set of patients who may benefit from ACL repair; however, careful patient selection and appropriate rehabilitation are necessary. 14,32
In this study, we identified several risk factors associated with a higher chance of ACL repair failure: age ≤17 and ≥35 years, elite level of competition, and active tobacco use. Additionally, patients with ACL repair failure had a significantly longer interval from their initial injury to surgery. Similar to our findings, Kaeding et al 23 found that younger age and higher activity level significantly increased the risk of ACLR failure. Furthermore, Cancienne et al 4 found that tobacco use led to a higher rate of revision ACLR after an index procedure. The findings of our study are in line with recent literature and may allow for better patient selection. Based on our findings, ACL repair is not recommended for high-level athletes, patients with active tobacco use, and those aged ≤17 and ≥35 years. Additionally, we believe time from injury to ACL repair to be critical in patient selection.
Limitations
This was a retrospective study in nature and therefore subject to bias. There is inherent selection bias, as patients selected for ACL repair had an arthroscopic evaluation to determine which treatment modality to undergo. Furthermore, this study represents a single surgeon’s technique and indications. An additional limitation of the study is that postoperative stability was assessed subjectively via patient telephone calls. Ideally, postoperative stability would be assessed using an instrumented measure such as a KT-2000 arthrometer. Lastly, our study was limited to a minimum 2-year follow-up. As previously mentioned, a longer term follow-up is necessary.
Conclusion
Primary arthroscopic ACL repair with suture tape augmentation resulted in unacceptably high failure rates at 2-year follow-up in a highly active military population. However, we identified that age ≤17 and ≥35 years, elite level of competition, time from injury to surgery, and active tobacco use were independent risk factors for ACL repair failure. We believe that consideration of these risk factors may allow for better patient selection to improve ACL repair failure rates.
Footnotes
Final revision submitted August 20, 2022; accepted September 26, 2022.
One or more of the authors has declared the following potential conflict of interest or source of funding: B.J.M. has received grant support from Arthrex and education payments from Smith & Nephew. L.Z. has received grant support from Arthrex and hospitality payments from Stryker. K.S.M. has received grant support from Arthrex and Zimmer Biomet and education payments from Smith & Nephew. C.R.B. has received education payments and speaking fees from Arthrex and honoraria from the Musculoskeletal Transplant Foundation. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
Ethical approval for this study was waived by Tripler Army Medical Center.
References
- 1. Ajuied A, Wong F, Smith C. Anterior cruciate ligament injury and radiologic progression of knee osteoarthritis: a systematic review and meta-analysis. Am J Sports Med. 2014;42:2242–2252. [DOI] [PubMed] [Google Scholar]
- 2. Andersson C, Odensten M, Good L, Gillquist J. Surgical or non-surgical treatment of acute rupture of the anterior cruciate ligament: a randomized study with long-term follow-up. J Bone Joint Surg Am. 1989;71(7):965–974. [PubMed] [Google Scholar]
- 3. Antosh IJ, Patzkowski JC, Racusin AW, Aden JK, Waterman SM. Return to military duty after anterior cruciate ligament reconstruction. Mil Med. 2018;183(1-2):e83–e89. [DOI] [PubMed] [Google Scholar]
- 4. Cancienne JM, Gwathmey FW, Miller MD, Werner BC. Tobacco use is associated with increased complications after anterior cruciate ligament reconstruction. Am J Sports Med. 2016;44(1):99–104. [DOI] [PubMed] [Google Scholar]
- 5. Chahla J, Nelson T, Dallo I, et al. Anterior cruciate ligament repair versus reconstruction: a kinematic analysis. Knee. 2020;27(2):334–340. [DOI] [PubMed] [Google Scholar]
- 6. Cruz CA, Goldberg D, Wake J, et al. Comparing bone-tendon autograft with bone-tendon-bone autograft for ACL reconstruction: a matched-cohort analysis. Orthop J Sports Med. 2020;8(12):2325967120970224. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7. DiFelice GS, van der List JP. Arthroscopic primary repair of proximal anterior cruciate ligament tears. Arthrosc Tech. 2016;5(5):e1057–e1061. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8. DiFelice GS, Villegas C, Taylor SA. Anterior cruciate ligament preservation: early results of a novel arthroscopic technique for suture anchor primary anterior cruciate ligament repair. Arthroscopy. 2015;31:2162–2171. [DOI] [PubMed] [Google Scholar]
- 9. Engebretsen L, Benum P, Fasting O, Mølster A, Strand T. A prospective, randomized study of three surgical techniques for treatment of acute ruptures of the anterior cruciate ligament. Am J Sports Med. 1990;18(6):585–590. [DOI] [PubMed] [Google Scholar]
- 10. Feagin JA, Jr, Curl WW. Isolated tear of the anterior cruciate ligament: 5-year follow-up study. Am J Sports Med. 1976;4:95–100. [DOI] [PubMed] [Google Scholar]
- 11. Ferretti A, Monaco E, Annibaldi A, et al. The healing potential of an acutely repaired ACL: a sequential MRI study. J Orthop Traumatol. 2020;21(1):14. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12. Frosch KH, Stengel D, Brodhun T. Outcomes and risks of operative treatment of rupture of the anterior cruciate ligament in children and adolescents. Arthroscopy. 2010;26:1539–1550. [DOI] [PubMed] [Google Scholar]
- 13. Gagliardi AG, Carry PM, Parikh HB, Traver JL, Howell DR, Albright JC. ACL repair with suture ligament augmentation is associated with a high failure rate among adolescent patients. Am J Sports Med. 2019;47(3):560–566. [DOI] [PubMed] [Google Scholar]
- 14. Gee MSM, Peterson CDR, Zhou ML, Bottoni CR. Anterior cruciate ligament repair: historical perspective, indications, techniques, and outcomes. J Am Acad Orthop Surg. 2020;28(23):963–971. [DOI] [PubMed] [Google Scholar]
- 15. Genelin F, Trost A, Primavesi C, Knoll P. Late results following proximal reinsertion of isolated ruptured ACL ligaments. Knee Surg Sports Traumatol Arthrosc. 1993;1:17–19. [DOI] [PubMed] [Google Scholar]
- 16. Heitmann M, Dratzidis A, Jagodzinski M, et al. Ligament bracing: augmented cruciate ligament sutures. Biomechanical studies of a new treatment concept. Unfallchirurg. 2014;117(7):650–657. [DOI] [PubMed] [Google Scholar]
- 17. Heusdens CHW, Blockhuys K, Roelant E, Dossche L, Van Glabbeek F, Van Dyck P. Suture tape augmentation ACL repair, stable knee, and favorable PROMs, but a re-rupture rate of 11% within 2 years. Knee Surg Sports Traumatol Arthrosc. 2021;29(11):3706–3714. [DOI] [PubMed] [Google Scholar]
- 18. Heusdens CHW, Hopper GP, Dossche L, Roelant E, Mackay GM. Anterior cruciate ligament repair with independent suture tape reinforcement: a case series with 2-year follow-up. Knee Surg Sports Traumatol Arthrosc. 2019;27(1):60–67. [DOI] [PubMed] [Google Scholar]
- 19. Hoogeslag RAG, Brouwer RW, Boer BC, de Vries AJ, Huis In‘t Veld R. Acute anterior cruciate ligament rupture: repair or reconstruction? Two-year results of a randomized controlled clinical trial. Am J Sports Med. 2019;47(3):567–577. [DOI] [PubMed] [Google Scholar]
- 20. Houck DA, Kraeutler MJ, Belk JW, Goode JA, Mulcahey MK, Bravman JT. Primary arthroscopic repair of the anterior cruciate ligament: a systematic review of clinical outcomes. Arthroscopy. 2019;35(12):3318–3327. [DOI] [PubMed] [Google Scholar]
- 21. Hurley ET, Mojica ES, Haskel JD, et al. Return to play testing following anterior cruciate reconstruction: a systematic review & meta-analysis. Knee. 2022;34:134–140. [DOI] [PubMed] [Google Scholar]
- 22. Jonkergouw A, van der List JP, DiFelice GS. Arthroscopic primary repair of proximal anterior cruciate ligament tears: outcomes of the first 56 consecutive patients and the role of additional internal bracing. Knee Surg Sports Traumatol Arthrosc. 2019;27(1):21–28. [DOI] [PubMed] [Google Scholar]
- 23. Kaeding CC, Pedroza AD, Reinke EK, Huston LJ. MOON Consortium, Spindler KP. Risk factors and predictors of subsequent ACL injury in either knee after ACL reconstruction: prospective analysis of 2488 primary ACL reconstructions from the MOON cohort. Am J Sports Med. 2015;43(7):1583–1590. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24. Murray MM, Fleming BC. Use of a bioactive scaffold to stimulate anterior cruciate ligament healing also minimizes posttraumatic osteoarthritis after surgery. Am J Sports Med. 2013;41:1762–1770. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25. Murray MM, Kiapour AM, Kalish LA, et al. Predictors of healing ligament size and magnetic resonance signal intensity at 6 months after bridge-enhanced anterior cruciate ligament repair. Am J Sports Med. 2019;47(6):1361–1369. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26. Nau T, Teuschl A, Ebner A, Jung I, Schenk C. Low revision rate and excellent subjective outcome of primary ACL repair with a minimum follow-up of 5 years. Muscles Ligaments Tendons J. 2018;8(2):185–190. [Google Scholar]
- 27. Nguyen DTT, Ramwadhdoebe THH, van der Hart CPP, Blankevoort L, Tak PPP, van Dijk CNN. Intrinsic healing response of the human anterior cruciate ligament: an histological study of reattached ACL remnants. J Orthop Res. 2014;32(2):296–301. [DOI] [PubMed] [Google Scholar]
- 28. Nwachukwu BU, Patel BH, Lu Y, Allen AA, Williams RJ, 3rd. Anterior cruciate ligament repair outcomes: an updated systematic review of recent literature. Arthroscopy. 2019;35(7):2233–2247. [DOI] [PubMed] [Google Scholar]
- 29. Odensten M, Lysholm J, Gillquist J. Suture of fresh ruptures of the anterior cruciate ligament: a 5-year follow-up. Acta Orthop Scand. 1984;55:270–272. [DOI] [PubMed] [Google Scholar]
- 30. O’Donoghue DH. Surgical treatment of fresh injuries to the major ligaments of the knee. J Bone Joint Surg Am. 1950;32-A:721–738. [PubMed] [Google Scholar]
- 31. Schneider KN, Schliemann B, Gosheger G, et al. Good to excellent functional short-term outcome and low revision rates following primary anterior cruciate ligament repair using suture augmentation. J Clin Med. 2020;9(10):3068. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 32. Senorski EH, Samuelsson K, Thomeé C, Beischer S, Karlsson J, Thomeé R. Return to knee-strenuous sport after anterior cruciate ligament reconstruction: a report from a rehabilitation outcome registry of patient characteristics. Knee Surg Sports Traumatol Arthrosc. 2017;25(5):1364–1374. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 33. Sherman MF, Lieber L, Bonamo JR, Podesta L, Reiter I. The long-term follow-up of primary anterior cruciate ligament repair: defining a rationale for augmentation. Am J Sports Med. 1991;19:243–255. [DOI] [PubMed] [Google Scholar]
- 34. Strand T, Molster A, Hordvik M, Krukhaug Y. Long-term follow-up after primary repair of the anterior cruciate ligament: clinical and radiological evaluation 15-23 years postoperatively. Arch Orthop Trauma Surg. 2005;125:217–221. [DOI] [PubMed] [Google Scholar]
- 35. van der List JP, Jonkergouw A, van Noort A, Kerkhoffs GMMJ, DiFelice GS. Identifying candidates for arthroscopic primary repair of the anterior cruciate ligament: a case-control study. Knee. 2019;26(3):619–627. [DOI] [PubMed] [Google Scholar]
- 36. van der List JP, Vermeijden HD, Sierevelt IN, DiFelice GS, van Noort A, Kerkhoffs GMMJ. Arthroscopic primary repair of proximal anterior cruciate ligament tears seems safe but higher level of evidence is needed: a systematic review and meta-analysis of recent literature. Knee Surg Sports Traumatol Arthrosc. 2020;28(6):1946–1957. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 37. van Eck CF, Limpisvasti O, ElAttrache NS. Is there a role for internal bracing and repair of the anterior cruciate ligament? A systematic literature review. Am J Sports Med. 2018;46(9):2291–2298. [DOI] [PubMed] [Google Scholar]
- 38. Vermeijden HD, van der List JP, O’Brien R, DiFelice GS. Patients forget about their operated knee more following arthroscopic primary repair of the anterior cruciate ligament than following reconstruction. Arthroscopy. 2020;36(3):797–804. [DOI] [PubMed] [Google Scholar]
- 39. Vermeijden HD, van der List JP, O’Brien R, DiFelice GS. Return to sports following arthroscopic primary repair of the anterior cruciate ligament in the adult population. Knee. 2020;27(3):906–914. [DOI] [PubMed] [Google Scholar]
- 40. Wilson WT, Hopper GP, Byrne PA, MacKay GM. Anterior cruciate ligament repair with internal brace ligament augmentation. Surg Technol Int. 2016;29:273–278. [PubMed] [Google Scholar]