Anterior cruciate ligament reconstruction autograft choice: bone-tendon-bone versus hamstring: does it really matter? A systematic review

Predictors of clinical outcome following revision anterior cruciate ligament reconstruction

The underlying theme throughout this series of studies authored by the Multicenter anterior cruciate ligament (ACL) Revision Study consortium has been to determine the modifiable predictors or risk factors of long-term outcomes of revision ACL reconstruction. The observational studies described and summarized in the manuscript are both clinically relevant and of great interest in finding out the long-term consequences of the intervention and its relationship to the original injury. The successful completion of these studies has important implications for both therapy and future clinical trials. The identification of modifiable risk factors will play an important role in secondary prevention, while the identification of nonmodifiable risk factors will aid us in counseling our patients and making surgical decisions. Thus, we expect a profound clinical impact on patients' care. More importantly, this project represents an important step forward in bringing evidence to bear in clinical decision making in orthopedic surgery.

Athletes With Bone-Patellar Tendon-Bone Autograft for Anterior Cruciate Ligament Reconstruction Were Slower to Meet Rehabilitation Milestones and Return-to-Sport Criteria Than Athletes With Hamstring Tendon Autograft or Soft Tissue Allograft : Secondary Analysis From the ACL-SPORTS Trial

OBJECTIVE

Graft choices for athletes undergoing anterior cruciate ligament reconstruction (ACLR) include bone-patellar tendon-bone (BPTB) and hamstring tendon (HT) autografts and soft tissue allografts. The objective was to assess time to meet clinical milestones by graft type in athletes who completed a return-to-sport (RTS) program after ACLR.

DESIGN

Retrospective cohort study.

METHODS

Seventy-nine athletes enrolled after ACLR (allograft, n = 18; BPTB, n = 24; HT, n = 37). Time from surgery to meet (1) enrollment criteria (12 or more weeks post surgery, 80% or greater isometric quadriceps strength index, minimal effusion, and full knee range of motion), and (2) RTS criteria (90% or greater quadriceps strength index, hop testing limb symmetry, and patient-reported outcomes) was calculated. Quadriceps strength, hop performance, and patient-reported outcomes were measured before and after training, and at 1 year post surgery. Descriptive statistics, chi-square tests, and 1-way analyses of variance (α = .05) were used to analyze differences among graft types.

RESULTS

On average, the BPTB group (28.5 ± 7.6 weeks) took longer to meet enrollment milestones than the HT (22.5 ± 7.6 weeks, P = .007) and allograft (18.9 ± 5.8 weeks, P<.001) groups. The BPTB group (44.7 ± 15.8 weeks) took longer from surgery to meet RTS criteria than the HT (32.5 ± 9.9 weeks, P = .001) and allograft (29.3 ± 9.0 weeks, P<.001) groups. After training, the quadriceps strength index was lower in the BPTB group (86.1% ± 11.4%) than it was in the HT (96.1% ± 12.9%, P = .004) and allograft (96.9% ± 5.9%, P = .009) groups.

CONCLUSION

Athletes with a BPTB autograft may take longer than athletes with an HT autograft or a soft tissue allograft to complete postoperative rehabilitation, recover quadriceps strength, and meet RTS criteria. J Orthop Sports Phys Ther 2020;50(5):259-266. Epub 27 Nov 2019. doi:10.2519/jospt.2020.9111.

Is anterior cruciate ligament graft rupture (after successful anterior cruciate ligament reconstruction and return to sports) actually a graft failure or a re-injury?

PURPOSE

The objective of this study is to discuss the fact that whether graft rupture after successful anterior cruciate ligament (ACL) reconstruction surgery is due to graft failure or re-injury to the reconstructed ACL.

METHODS

In total, 340 sportspersons, meeting our inclusion criteria, were assessed for rupture of ipsilateral ACL graft and ACL injury of the contralateral knee. Patients with ipsilateral ACL graft rupture were labelled as group 1, while those with contralateral ACL injury were labelled as group 2. Both groups were compared for potential risk factors for ACL injury, and statistical analysis was performed to study whether the graft acted as an additional risk factor.

RESULTS

Of the 340 sportspersons, 25 patients suffered a total of 26 injuries. Ipsilateral graft rupture rate was 2.4% (8 of 340) at a mean follow-up of 25.5 ± 40.57 months, and the contralateral ACL injury rate was 5.3% (18 of 340) at a mean follow-up of 18.11 ± 19.97 months, with an overall re-injury rate of 7.6%. Both groups were comparable for risk factors for ACL injury: age ( p = 0.255), gender ( p = 0.534), mode of re-injury ( p = 0.523), level of sports activity, type of graft used ( p = 0. 918), graft diameter ( p = 0.607), duration from injury to index surgery ( p = 0.492), duration from index surgery to re-injury ( p = 0.638), timing of return to sports after index surgery ( p = 0.303), duration of sporting activity before second injury ( p = 0.657), and Tegner's level of sports activity ( p = 0.486).

CONCLUSION

Because the rate of contralateral ACL injury is higher than the ipsilateral graft rupture and the risk factors for ACL injury are comparable in both groups at a follow-up period, which is suggestive of ligamentization of the graft, we suggest that it might be an ACL re-injury rather than graft failure. Level of Evidence: Level III (Retrospective cohort study).

The Warrior Athlete Part 2-Return to Duty in the US Military: Advancing ACL Rehabilitation in the Tactical Athlete

Rehabilitation following an anterior cruciate ligament reconstruction is a crucial component of the healing and recovery process and full return to duty/play in the tactical modern-day warfighter. The burden of anterior cruciate ligament injuries and subsequent loss of readiness in these military warfighters highlights one of the most significant gaps in musculoskeletal injury care today. Emphasis must be placed on early weight-bearing and range of motion (ROM), namely in this athlete population, to best facilitate a timely care and recovery process. Preoperative rehabilitation should commence immediately following the diagnosis of an anterior cruciate ligament tear, because one of the best predictors of postoperative ROM is preoperative ROM. Recent advances in rehabilitation technology such as Alter-G treadmills, inertial measurement units, and blood flow restriction therapy systems, have demonstrated success in the early rehabilitation of tactical athletes. Alter-G treadmills allow for early weight-bearing with reduced impact and progression in ROM following operative management, while inertial measurement units have been applied to tailoring rehabilitation protocols specifically to an athlete's unique functional deficits. When used in conjunction with a fined tune rehabilitation protocol, implemented by a well versed clinical team, these treatment techniques can greatly expedite the return to duty process and limit long-term complications.

Factors associated with revision following anterior cruciate ligament reconstruction: A systematic review of registry data

BACKGROUND

To identify the patient and surgical factors associated with revision anterior cruciate ligament (ACL) reconstruction as reported by all national and community ACL registries.

METHODS

A systematic review was performed on the MEDLINE, Embase and Cochrane Library databases. Eligibility criteria included English studies published by national or community ACL registries reporting on primary ACL reconstruction and risk factors associated with revision ACL reconstruction.

RESULTS

Thirty-three studies from the Swedish, Norwegian, Danish and Kaiser Permanente registries were included for review. Fourteen studies from all four registries reported younger age as a risk factor for revision ACL reconstruction. In addition, the Swedish registry reported concomitant medial collateral ligament (MCL) injury, undergoing earlier surgery, lower Knee Injury and Osteoarthritis Outcome Score (KOOS), smaller graft diameter and an anteromedial portal drilling technique as risk factors for revision. The risk factors reported by the Norwegian registry included lower body mass index (BMI), lower KOOS, hamstring tendon grafts and suspensory fixation. The Danish registry reported hamstring tendon grafts, anteromedial portal drilling and suspensory fixation as risk factors. The Kaiser Permanente registry reported male sex, lower BMI, ethnicity, hamstring tendon grafts, allografts, smaller graft diameter and an anteromedial portal technique as risk factors for revision.

CONCLUSION

Multiple patient and surgical factors were associated with increased risk of revision ACL reconstruction in registries. Younger age and the use of hamstring tendon grafts were consistently reported as risk factors for failure.

Factors Influencing Return to Play and Second Anterior Cruciate Ligament Injury Rates in Level 1 Athletes After Primary Anterior Cruciate Ligament Reconstruction: 2-Year Follow-up on 1432 Reconstructions at a Single Center

BACKGROUND

Despite the importance of return-to-play (RTP) rates, second anterior cruciate ligament (ACL) injury rates, and patient-reported outcomes of athletes returning to sports after ACL reconstruction (ACLR), these outcomes have not been evaluated together across a single cohort nor the pre- and intraoperative factors influencing outcomes explored.

PURPOSE

To prospectively report outcomes after ACLR relating to RTP, second ACL injury, and International Knee Document Committee (IKDC) scores in a large cohort of athletes at a single center to examine the influence of pre- and intraoperative variables on these outcomes.

DESIGN

Cohort study; Level of evidence, 3.

METHODS

A consecutive cohort of 1432 athletes undergoing primary ACLR by 2 orthopaedic surgeons was followed up prospectively more than 2 years after surgery. Pre- and intraoperative findings were reported with outcomes at follow-up relating to RTP, second ACL injury, and IKDC. Between-group differences for each outcome were reported and the predictive ability of pre- and intraoperative variables relating to each outcome assessed with logistic regression.

RESULTS

There was >95% follow-up 2 years after surgery. The RTP rate was 81%, and of those who returned, 1.3% of those with patellar tendon grafts and 8.3% of those with hamstring grafts experienced ipsilateral rerupture (hazard ratio, 0.17). The contralateral ACL injury rate was 6.6%, and the IKDC score at follow-up was 86.8, with a greater proportion of patients with patellar tendon grafts scoring <80 on the IKDC (odds ratio, 1.56; 95% CI, 1.15-3.12). There was no relationship between time to RTP and second ACL injury, and there was a moderate correlation between ACL-Return to Sport After Injury score and RTP at follow-up (P < .001, rho = 0.46). There were a number of differences in pre- and intraoperative variables between groups for each outcome, but they demonstrated a poor ability to predict outcomes in level 1 athletes at 2-year follow-up.

CONCLUSION

Findings demonstrated high overall RTP rates, lower reinjury rates with patellar tendon graft after 2-year follow-up in level 1 athletes, and no influence of time to RTP on second ACL injury. Despite differences between groups, there was poor predictive ability of pre- and intraoperative variables. Results suggest pre- and intraoperative variables for consideration to optimize outcomes in level 1 athletes after ACLR, but future research exploring other factors, such as physical and psychological recovery, may be needed to improve outcome prediction after ACLR.

REGISTRATION

NCT02771548 (ClinicalTrials.gov identifier).

Anterior Cruciate Ligament Reconstruction in High School and College-Aged Athletes: Does Autograft Choice Influence Anterior Cruciate Ligament Revision Rates?

BACKGROUND

Physicians' and patients' decision-making process between bone-patellar tendon-bone (BTB) and hamstring tendon autografts for anterior cruciate ligament (ACL) reconstruction (ACLR) may be influenced by a variety of factors in the young, active athlete.

PURPOSE

To determine the incidence of both ACL graft revisions and contralateral ACL tears resulting in subsequent ACLR in a cohort of high school- and college-aged athletes who initially underwent primary ACLR with either a BTB or a hamstring autograft.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Study inclusion criteria were patients aged 14 to 22 years who were injured in sports, had a contralateral normal knee, and were scheduled to undergo unilateral primary ACLR with either a BTB or a hamstring autograft. All patients were prospectively followed for 6 years to determine whether any subsequent ACLR was performed in either knee after their initial ACLR. Multivariable regression modeling controlled for age, sex, ethnicity/race, body mass index, sport and competition level, baseline activity level, knee laxity, and graft type. The 6-year outcomes were the incidence of subsequent ACLR in either knee.

RESULTS

A total of 839 patients were eligible, of which 770 (92%) had 6-year follow-up for the primary outcome measure of the incidence of subsequent ACLR. The median age was 17 years, with 48% female, and the distribution of BTB and hamstring grafts was 492 (64%) and 278 (36%), respectively. The incidence of subsequent ACLR at 6 years was 9.2% in the ipsilateral knee, 11.2% in the contralateral normal knee, and 19.7% for either knee. High-grade preoperative knee laxity (odds ratio [OR], 2.4 [95% confidence interval [CI], 1.4-3.9]; P = .001), autograft type (OR, 2.1 [95% CI, 1.3-3.5]; P = .004), and age (OR, 0.8 [95% CI, 0.7-1.0]; P = .009) were the 3 most influential predictors of ACL graft revision in the ipsilateral knee. The odds of ACL graft revision were 2.1 times higher for patients receiving a hamstring autograft than patients receiving a BTB autograft (95% CI, 1.3-3.5; P = .004). No significant differences were found between autograft choices when looking at the incidence of subsequent ACLR in the contralateral knee.

CONCLUSION

There was a high incidence of both ACL graft revisions and contralateral normal ACL tears resulting in subsequent ACLR in this young athletic cohort. The incidence of ACL graft revision at 6 years after index surgery was 2.1 times higher with a hamstring autograft compared with a BTB autograft.

Effect of Graft Choice on Revision and Contralateral Anterior Cruciate Ligament Reconstruction: Results From the New Zealand ACL Registry

BACKGROUND

The patellar tendon is often considered the "gold standard" graft for reducing the risk of graft rupture after anterior cruciate ligament (ACL) reconstruction. However, its use may also be associated with an increased risk of injury to the contralateral ACL.

PURPOSE

To clarify the association between graft choice and the risk of revision and contralateral ACL reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Prospective data captured by the New Zealand ACL Registry between April 2014 and December 2018 were reviewed. All primary ACL reconstructions performed using either a hamstring tendon or patellar tendon autograft were included. Cox regression survival analysis adjusting for patient factors was performed to compare the risk of revision and contralateral ACL reconstruction between the hamstring tendon graft and the patellar tendon graft.

RESULTS

A total of 7155 primary ACL reconstructions were reviewed, of which 5563 (77.7%) were performed using a hamstring tendon graft and 1592 (22.3%) were performed using a patellar tendon graft. Patients with a hamstring tendon graft had a revision rate of 2.7% compared with 1.3% in patients with a patellar tendon graft (adjusted hazard ratio [HR], 2.51; 95% CI, 1.55-4.06; P < .001). The patellar tendon graft was associated with an increased risk of contralateral ACL reconstruction compared with the hamstring tendon graft (adjusted HR, 1.91; 95% CI, 1.15-3.16; P = .012). The number needed to treat (NNT) with a patellar tendon graft to prevent 1 revision was 73.6. However, the NNT with a hamstring tendon graft to prevent 1 contralateral reconstruction was 116.3.

CONCLUSION

Use of a patellar tendon graft reduced the risk of graft rupture but was associated with an increased risk of injury to the contralateral ACL. Adequate rehabilitation and informed decision making on return to activity and injury prevention measures may be important in preventing subsequent injury to the healthy knee.

Arthrofibrosis Following Anterior Cruciate Ligament Reconstruction

Introduction: Anterior cruciate ligament (ACL) tear is a frequent injury and its reconstruction is among the most commonly performed orthopaedic surgical procedures. ACL reconstruction generally yields good results. However, its recovery can be hampered by the development of postoperative complications. The aim of this study was to review complications following arthroscopic ACL reconstruction done in Hospital Raja Permaisuri Bainun, Ipoh and Hospital Teluk Intan, Perak with the emphasis on arthrofibrosis. Arthrofibrosis is defined as a loss of 15 degrees extension or more, with or without flexion loss compared to the contralateral knee. Materials and Methods: The study is based on a series of retrospective cases, on which medical records of 200 patients who underwent ACL reconstruction surgeries between March 2007 and December 2014 were reviewed. Follow-up treatment records were available for 166 patients (83%). The data was analysed to identify the risk factors for developing complications with an emphasis on arthrofibrosis. Results: Eight patients (5%) developed arthrofibrosis in the post-operative period. Early surgical intervention, preoperative limited range of motion and female gender are the risk factors correlate with arthrofibrosis. However, the type of graft used and meniscal procedure do not have a significant correlation with the development of arthrofibrosis. Other complications encountered are local infections, hypertrophic scar and chronic regional pain syndromes. Conclusion: The 5% incidence of arthrofibrosis following an ACL reconstruction in our centres can be reduced with proper preventive measures which include thorough preoperative evaluation, proper patient selection, restoration of ROM prior to surgery and proper timing of surgery.

The significant effect of the medial hamstrings on dynamic knee stability

PURPOSE

While hamstring autograft is a popular option for the general population, BTB autograft is still significantly more popular among professional athletes due to concerns of altering knee kinematics with hamstring harvest. This study seeks to quantify the contribution of the medial hamstrings to knee stability.

METHODS

Valgus knee laxity, anterior tibial translation, and rotational motion were measured in eight fresh-frozen cadaveric knees after forces were applied on the tibia in each plane (coronal, sagittal, and axial). Four muscle loading conditions were tested: (1) physiologic fully loaded pes anserinus, (2) semitendinosus only loaded, (3) gracilis only loaded, and (4) unloaded pes anserinus. The protocol was then repeated with the ACL transected.

RESULTS

In the ACL intact knee, the neutral position of the tibia with an unloaded pes anserinus was significantly more externally rotated (p < 0.01) and anteriorly translated (p < 0.05) at all knee flexion angles than a tibia with a physiologic loaded pes anserinus. Applying an external rotation torque significantly increased external rotation for the fully unloaded (p < 0.001), gracilis only loaded (p < 0.001), and semitendinosus only loaded (p < 0.01) conditions at all flexion angles. Applying a valgus torque resulted in a significant increase in laxity for the fully unloaded condition only at 30° of flexion (p < 0.05). Applying an anterior tibial force resulted in significant increase in anterior translation for the fully unloaded condition at all flexion angles (p < 0.01), and for the gracilis only loaded condition in 30° and 60° of flexion (p < 0.05). Similar results were seen in the ACL deficient model.

CONCLUSION

The medial hamstrings are involved in rotational, translational, and varus/valgus control of the knee. Applying anterior, external rotation, and valgus forces on the hamstring deficient knee significantly increases motion in those planes. Harvesting the gracilis and semitendinosus tendons alters native knee kinematics and stability. This is clinically relevant and should be a consideration when choosing graft source for ACL reconstruction, especially in the elite athlete population.

Timeline for Maximal Subjective Outcome Improvement After Anterior Cruciate Ligament Reconstruction

BACKGROUND

Anterior cruciate ligament (ACL) tears are one of the most common traumatic knee injuries experienced by athletes. Return to sport is considered the pinnacle endpoint among patients receiving ACL reconstruction. However, at the time of return to sport, patients may not be participating at their previous levels of function, as defined by clinical metrics.

PURPOSE

To establish when patients perceive maximal subjective medical improvement according to patient-reported outcome measures (PROMs).

STUDY DESIGN

Systematic review.

METHODS

A systematic review of the PubMed database was conducted to identify studies that reported sequential PROMs up to a minimum of 2 years after ACL reconstruction. Pooled analysis was conducted for PROMs at follow-up points of 3 months, 6 months, 1 year, and 2 years. Clinically significant improvement was determined between pairs of intervals with the minimal clinically important difference.

RESULTS

This review contains 30 studies including 2253 patients who underwent ACL reconstruction. Clinically significant improvement in the KOOS (Knee injury and Osteoarthritis Outcome Score) was seen up to 1 year after ACL reconstruction, but no clinical significance was noted from 1 to 2 years. Clinically significant improvement in the IKDC (International Knee Documentation Committee) and Lysholm questionnaires was seen up to 6 months postoperatively, but no clinical significance was noted beyond that.

CONCLUSION

After ACL reconstruction, maximal subjective medical improvement is established 1 year postoperatively, with no further perceived clinical improvement beyond this time point according to current PROMs. The KOOS may be a more responsive metric to subjective improvements in this patient cohort than other patient-reported outcomes, such as the IKDC and Lysholm.

CLINICAL RELEVANCE

After ACL reconstruction, patients perceive interval subjective improvements until 1 year postoperatively.

Predictors of Patient-Reported Outcomes at 2 Years After Revision Anterior Cruciate Ligament Reconstruction

BACKGROUND

Patient-reported outcomes (PROs) are a valid measure of results after revision anterior cruciate ligament (ACL) reconstruction. Revision ACL reconstruction has been documented to have worse outcomes when compared with primary ACL reconstruction. Understanding positive and negative predictors of PROs will allow surgeons to modify and potentially improve outcome for patients.

PURPOSE/HYPOTHESIS

The purpose was to describe PROs after revision ACL reconstruction and test the hypothesis that patient- and technique-specific variables are associated with these outcomes.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Patients undergoing revision ACL reconstruction were identified and prospectively enrolled by 83 surgeons over 52 sites. Data included baseline demographics, surgical technique and pathology, and a series of validated PRO instruments: International Knee Documentation Committee (IKDC), Knee injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Index, and Marx Activity Rating Scale. Patients were followed up at 2 years and asked to complete the identical set of outcome instruments. Multivariate regression models were used to control for a variety of demographic and surgical factors to determine the positive and negative predictors of PRO scores at 2 years after revision surgery.

RESULTS

A total of 1205 patients met the inclusion criteria and were successfully enrolled: 697 (58%) were male, with a median cohort age of 26 years. The median time since their most recent previous ACL reconstruction was 3.4 years. Two-year questionnaire follow-up was obtained from 989 patients (82%). The most significant positive predictors of 2-year IKDC scores were a high baseline IKDC score, high baseline Marx activity level, male sex, and having a longer time since the most recent previous ACL reconstruction, while negative predictors included having a lateral meniscectomy before the revision ACL reconstruction or having grade 3/4 chondrosis in either the trochlear groove or the medial tibial plateau at the time of the revision surgery. For KOOS, having a high baseline score and having a longer time between the most recent previous ACL reconstruction and revision surgery were significant positive predictors for having a better (ie, higher) 2-year KOOS, while having a lateral meniscectomy before the revision ACL reconstruction was a consistent predictor for having a significantly worse (ie, lower) 2-year KOOS. Statistically significant positive predictors for 2-year Marx activity levels included higher baseline Marx activity levels, younger age, male sex, and being a nonsmoker. Negative 2-year activity level predictors included having an allograft or a biologic enhancement at the time of revision surgery.

CONCLUSION

PROs after revision ACL reconstruction are associated with a variety of patient- and surgeon-related variables. Understanding positive and negative predictors of PROs will allow surgeons to guide patient expectations as well as potentially improve outcomes.

Hamstring Braid Graft Technique for Anterior Cruciate Ligament Reconstruction

Hamstring autograft is one of the most used grafts for anterior cruciate ligament (ACL) reconstruction, although there are several graft preparation techniques. It is extremely difficult to mimic the biomechanical properties of the native ACL; thus, it is important to achieve a proper graft configuration, diameter, and length. To avoid reruptures, an optimal and reproducible hamstring autograft is desired. Hamstring autograft has been traditionally devalued when compared with other options such as bone-patellar tendon-bone autograft. The purpose of this Technical Note is to describe in detail a hamstring braid graft configuration that could potentially overcome the past disadvantages of ACL reconstruction.

Return to Sport Following Revision Anterior Cruciate Ligament Reconstruction in Athletes: A Systematic Review

PURPOSE

To report the rate of return to sport following revision anterior cruciate ligament (ACL) reconstruction in athletes.

METHODS

A systematic review of the literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted for athletes undergoing revision ACL reconstruction at a minimum 1-year follow-up. The primary outcome measure was return to sport following revision ACL reconstruction. Secondary outcomes were International Knee Documentation Committee score, Knee Injury and Osteoarthritis Outcome Score, Tegner and Lysholm scores, KT-1000 arthrometer measurements, and rates of ACL rerupture. A subjective analysis was performed, and data were summarized using forest plots, ranges, and tables.

RESULTS

Thirteen studies met the inclusion criteria. The rate of return to sport at any level ranged from 56% to 100%. The rate of return to sport at preinjury level ranged from 13% to 69%. The average time to return to sport ranged from 6.7 to 12 months. The average patient-reported outcome scores ranged from 43% to 86% (International Knee Documentation Committee score), 45% to 95% (Knee Injury and Osteoarthritis Outcome Score), 4.3 to 9 (Tegner), and 84% to 91% (Lysholm). KT-1000 arthrometer measurements ranged from 1.2 to 3.1 mm. Rates of ACL rerupture ranged from 0% to 20%.

CONCLUSIONS

This systematic review demonstrated a relatively high rate of return to sport at any level in patients who underwent revision ACL reconstruction, but a relatively low rate of return to sport at preinjury level of play. Patient-reported outcomes were favorable, showing improvement at follow-up from preoperative scores. Rates of ACL rerupture were high relative to those reported for primary ACL reconstruction. This study suggests that athletes may have difficulty resuming their previous level of sport following revision ACL reconstruction but have a good chance of returning to a lower level of play.

LEVEL OF EVIDENCE

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

Anterior Cruciate Ligament Reconstruction in Young Female Athletes: Patellar Versus Hamstring Tendon Autografts

BACKGROUND

Female athletes are 2 to 8 times more prone to anterior cruciate ligament (ACL) rupture than males. Furthermore, reinjury to the ipsilateral or contralateral knee can occur in >20% of athletes. Female sex and younger age are known risk factors for graft failure. The optimal graft choice for young females remains unknown and poorly studied.

PURPOSE/HYPOTHESIS

The authors aimed to compare clinical outcomes in young females who underwent ACL reconstruction (ACLR) with bone-patellar tendon-bone (BTB) and quadrupled hamstring (HS) autografts. It was hypothesized that no significant differences in outcomes exist between graft choices.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Female patients aged 15 to 25 years who underwent primary ACLR with BTB or HS autograft were included for review. Patients were subdivided into 2 age groups: 15 to 20 years and 21 to 25 years. The occurrence of chondral, meniscal, or ligamentous injury to either knee was recorded for comparison.

RESULTS

A total of 256 females were included (BTB, n = 175; HS, n = 81). The majority of patients were between the ages of 15 and 20 years (BTB, 80%; HS, 77.8%). Overall, graft rupture occurred in 23 patients (9%) and contralateral ACL tear occurred in 18 (7%). Subgroup analysis showed that 75% of BTB and 100% of HS graft retears occurred in females aged 15 to 20 years. Within this age group, there was a significantly lower rate of graft ruptures in the BTB group (6.4%) as compared with the HS group (17.5%, P = .02). Allograft augmentation was used in 4 of the 11 HS grafts that retore. When allograft-augmented grafts were excluded, there was no significant difference in graft failure rate between graft choices. Fifteen patients in the BTB group (12%) as opposed to 1 in the HS group (2%) reported extreme difficulty or the inability to kneel on the front of the knee (P = .04).

CONCLUSION

In females aged 15 to 20 years undergoing ACLR, BTB autograft may lead to fewer graft ruptures than HS autograft. While this difference was not observed in females aged 21 to 25 years, a larger sample may be required to accept the null hypothesis in this age group. BTB autograft significantly increased the risk of kneeling pain as compared with HS regardless of age.

Effectiveness of Reconstruction of the Anterior Cruciate Ligament with Quadrupled Hamstrings and Bone-Patellar Tendon-Bone Autografts

Background

The 2 most frequently used autografts for anterior cruciate ligament reconstruction are the bone-patellar tendon-bone and the quadrupled hamstrings tendon.

Hypothesis

Hamstring tendon graft is superior to patellar tendon graft in restoring tibial rotation during highly demanding activities because of its superiority in strength and linear stiffness and because it is closer morphologically to the anatomy of the natural anterior cruciate ligament.

Study Design

Case control study; Level of evidence, 3.

Methods

Eleven patients with patellar tendon graft anterior cruciate ligament reconstruction, 11 patients with hamstring tendon graft anterior cruciate ligament reconstruction, and 11 controls were assessed. Kinematic data were collected (50 Hz) with a 6-camera optoelectronic system while the subjects descended stairs and, immediately after, pivoted on their landing leg. The dependent variable examined was the tibial internal-external rotation during pivoting. All patients in both groups were also assessed clinically and with the use of a KT-1000 arthrometer to evaluate anterior tibial translation.

Results

The results demonstrated that reconstructions with either graft successfully restored anterior tibial translation. However, both anterior cruciate ligament reconstruction groups had significantly increased tibial rotation when compared with the controls, whereas no differences were found between the 2 reconstructed groups.

Conclusion

The 2 most frequently used autografts for anterior cruciate ligament reconstruction cannot restore tibial rotation to normal levels.

Clinical Relevance

New surgical techniques are needed that can better approximate the actual anatomy and function of the anterior cruciate ligament.

Anterior Cruciate Ligament Reconstruction in Young Females: A Systematic Review of Patellar Tendon Versus Hamstring Tendon Autografts

A systematic review was performed to compare patellar tendon-bone (BTB) and hamstring tendon (HS) autografts following anterior cruciate ligament reconstruction in young females, young patients, or females. One study compared BTB and HS in young females and found a lower rate of graft failure with BTB (P<.02). Of the 11 studies that made this comparison in females, 1 reported decreased laxity in females with BTB (P=.035). Of 4 studies comparing autografts in young patients, 1 reported a decreased rate of graft failure with BTB (P=.036). Further studies making this comparison specifically in young females are warranted. [Orthopedics. 2019; 42(3):e295-e304.].

Bridge-Enhanced Anterior Cruciate Ligament Repair: Two-Year Results of a First-in-Human Study

Background

Bridge-enhanced anterior cruciate ligament repair (BEAR) combines suture repair of the anterior cruciate ligament (ACL) with a specific extracellular matrix scaffold (the BEAR scaffold) that is placed in the gap between the torn ends of the ACL to facilitate ligament healing.

Purpose/Hypothesis

The purpose of this study was to report the 12- and 24-month outcomes of patients who underwent the BEAR procedure compared with a nonrandomized concurrent control group who underwent ACL reconstruction (ACLR) with an autograft. We hypothesized that the BEAR group would have physical examination findings, patient-reported outcomes, and adverse events that were similar to those of the ACLR group.

Study Design

Cohort study; Level of evidence, 2.

Methods

Ten patients underwent BEAR, and 10 underwent ACLR with a 4-stranded hamstring autograft. At 24 months, 9 of the 10 BEAR patients and 7 of the 10 ACLR patients completed a study visit. Outcomes reported included International Knee Documentation Committee (IKDC) subjective and objective results, knee anteroposterior (AP) laxity findings via an arthrometer, and functional outcomes.

Results

There were no graft or repair failures in the first 24 months after surgery. The IKDC subjective scores in both groups improved significantly from baseline (P < .0001) at 12 and 24 months, to 84.6 ± 17.2 in the ACLR group and to 91.7 ± 11.7 in the BEAR group. An IKDC objective grade of A (normal) was found in 44% of patients in the BEAR group and in 29% of patients in the ACLR group at 24 months; no patients in either group had C (abnormal) or D (severely abnormal) grades. Arthrometer testing demonstrated mean side-to-side differences in AP laxity that were similar in the 2 groups at 24 months (BEAR, 1.94 ± 2.08 mm; ACLR, 3.14 ± 2.66 mm). Functional hop testing results were similar in the 2 groups at 12 and 24 months after surgery. Hamstring strength indices were significantly higher in the BEAR group compared with the ACLR group (P = .0001).

Conclusion

In this small, first-in-human study, BEAR produced similar outcomes to ACLR with a hamstring autograft. BEAR may result in knee stability and patient-reported outcomes at 2 years sufficient to warrant longer term studies of efficacy in larger groups of patients.

Ankle Lateral Ligament Augmentation Versus the Modified Broström-Gould Procedure: A 5-Year Randomized Controlled Trial

BACKGROUND

"Ankle sprain" is a common injury, and >20% of patients may develop chronic instability for which surgery is indicated. The modified Broström-Gould (MBG) procedure remains the gold standard; however, there are a number of relative contraindications to this procedure, and the longer-term outcomes after the MBG have been questioned. An alternative procedure is augmentation of a primary repair with a ligament augmentation reconstruction system (LARS).

PURPOSE

To conduct a randomized controlled trial testing the null-hypothesis that there is no difference in patient scored outcomes and activity levels, between patients undergoing a MBG procedure compared with those undergoing a primary repair with LARS augmentation, for lateral ligament instability of the ankle.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

Patients who satisfied the inclusion criteria were invited to take part in the study. Patients were randomly allocated to undergo the LARS or MBG procedure. Both groups followed similar postoperative rehabilitation. Patients completed the Foot and Ankle Outcome Score (FAOS) before surgery and then at 1, 2, and 5 years after surgery. Tegner activity scores were recorded at 5years. The scores in the 2 groups were compared via statistical analysis ( P < .05).

RESULTS

Of the 50 patients satisfying the inclusion criteria, 47 agreed to take part in the study. Twenty-two were randomized to the LARS group and 25 to the MBG group. At 5 years, follow-up data were complete for 20 patients in the LARS group and 21 in the MBG. There were 2 failures in the MBG group and 0 in the LARS group. The LARS group had significantly better improvement in total FAOS at 1 year (mean ± SD, 92.4 ± 2.5 vs 78.2 ± 3.4, P = .005), 2 years (94.0 ± 3.0 vs 78.0 ± 5.2, P = .003), and 5 years (93.7 ± 6.0 vs 75.1 ± 5.5, P = .002) after surgery. The 5-year Tegner activity scores were higher in the LARS group (8.25 ± 1.1 vs 7.2 ± 0.9, P = .03).

CONCLUSION

Among physically active patients with chronic lateral ligament instability, primary repair combined with LARS results in better total FAOS at 5-year follow-up and higher Tegner activity scores as compared with the MBG procedure.

REGISTRATION

ACTRN12618000906257 (Australia New Zealand Clinical Trial Registry).

The presence of patellar tendinopathy in the bone-patellar tendon-bone autograft may increase the risk of anterior cruciate ligament graft failure

PURPOSE

The purpose of this study was to evaluate the influence of patellar tendinopathy on primary anterior cruciate ligament (ACL) reconstruction graft failure when using bone-patellar tendon-bone (BPTB) autograft.

METHODS

All patients undergoing primary ACL reconstruction using ipsilateral BPTB with preoperative magnetic resonance imaging (MRI) available for review were approached for eligibility. The medical charts of included patients were reviewed to obtain demographic information, anatomical characteristics, injury characteristics, treatment characteristics, length of follow-up, and presence of graft failure. A single, fellowship-trained, knee-specialist and blinded researcher performed preoperative MRI interpretation of patellar tendinopathy. The presence/absence of patellar tendinopathy (none, mild, moderate, or severe changes) was compared between patients with (cases) and without (controls) failure of ACL reconstruction. There were 559 cases with a median (range) clinical follow-up was 8 (4-30) months and an average age of 21.5 years (82% males).

RESULTS

Of the 559 cases, there were 182 (32.6%) with and 377 (67.4%) without patellar tendinopathy. A total of 32 (5.7%) graft failures occurred. There were a significantly higher failure rate in patients with compared to without patellar tendinopathy (p < 0.001), and in patients with compared to without partial tendon tear (p < 0.001). The odds ratio (95% confidence interval) for graft failure was 5.9 (2.7-13.1), 20.8 (6.8-63.9) and 54.4 (5.5-539.4) in patients with patellar tendinopathy (compared to absence of patellar tendinopathy), moderate or severe patellar tendinopathy (compared to none or mild patellar tendinopathy), or partial tendon tear (compared to absence of tendon tear), respectively.

CONCLUSION

The presence of patellar tendinopathy increases the risk of BPTB graft failure when used for ACL reconstruction. The use of BPTB autograft is not recommended if patellar tendinopathy is obvious or there are suspicious of partial tendon tear on MRI. In such cases, the surgeon should consider using a different graft.

LEVEL OF EVIDENCE

Retrospective cohort analysis, Level III.

Effect of Operative Time on Short-Term Adverse Events After Isolated Anterior Cruciate Ligament Reconstruction

Background:

A longer operative time has been previously recognized as a risk factor for short-term complications after various orthopaedic procedures; however, it has yet to be investigated as an independent risk factor for postoperative complications after anterior cruciate ligament (ACL) reconstruction.

Purpose:

To identify whether a longer operative time in ACL reconstruction is an independent risk factor for the development of postoperative complications, hospital readmissions, or an extended length of stay within 30 days of the index procedure.

Study Design:

Descriptive epidemiology study.

Methods:

Patients undergoing ACL reconstruction between 2005 and 2016 were identified using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. Cases with concomitant procedures were excluded from the analysis. We evaluated the association between operative time and preoperative variables such as patient age, sex, body mass index, comorbidities, and procedure. Correlations between adverse events and operative time, while controlling for the above preoperative variables, were calculated using multivariate Poisson regression with robust error variance.

Results:

A total of 14,159 procedures were included in this investigation. The mean patient age was 32.6 ± 10.8 years, the mean body mass index was 27.7 ± 6.5 kg/m², and the mean operative time was 89.7 ± 28.6 minutes. Patients who were between the ages of 18 and 30 years (mean operative time, 95.1 ± 27.8 minutes; relative risk [RR], 17.7; P < .001), male (mean operative time, 91.9 ± 28.3 minutes; RR, 4.7; P < .001), and nondiabetic (mean operative time, 89.8 ± 28.6 minutes; RR, 7.1; P = .011) were associated with a longer operative duration. The overall complication rate was 1.1%. After adjusting for demographic characteristics and procedures, 15-minute incremental increases in operative duration were associated with an increased risk of deep vein thrombosis (RR, 1.12; P = .042), surgical site infections (RR, 1.21; P = .001), and sepsis (RR, 1.66; P < .001) as well as increased readmission rates (RR, 1.23; P = .001) and an extended length of stay (RR, 1.18; P = .008).

Conclusion:

While the overall adverse risk rate after ACL reconstruction remains low, marginal increases in operative time are associated with an increased risk of adverse events such as deep vein thrombosis, surgical site infections, sepsis, an extended length of stay, and readmissions. Thus, the operating physician and surgical staff should make all efforts to coordinate and prepare for each case to maximize surgical efficiency.

Hamstring tendons or bone-patellar tendon-bone graft for anterior cruciate ligament reconstruction?

In anterior cruciate ligament (ACL) reconstruction, success depends on several factors: patient selection; surgical technique, taking account of associated meniscal and ligamentous lesions; and postoperative rehabilitation. Improved hamstring-tendon graft preparation and fixation techniques now provide results in terms of laxity and retear comparable to patellar tendon graft, which has long been the gold-standard for patients with strong functional demand, despite its higher risk of extension stiffness and anterior pain. Apart from a few exceptional preferential indications, such as hamstring tendon in growing children and patients whose lifestyle or occupation involves frequent kneeling and patellar tendon in case of severe medial laxity associated with ACL tear, either graft may be used for ACL reconstruction. The keypoints in the procedure are good tunnel positioning and hence good mastery of the surgical technique, and treatment of all associated lesions, and especially of occult meniscal lesions and rotational laxity due to anterolateral ligament deficiency, which requires associated extra-articular plasty. Graft choice is secondary and not a key to success.

Revision Anterior Cruciate Ligament Reconstruction in the Nonathlete Population

BACKGROUND

There is considerable literature about revision anterior cruciate ligament (ACL) reconstruction in athletes vut there is little published evidence about the same in the nonathletes. The injury itself may remain underdiagnosed and untreated in nonsports persons. This study highlights the high incidence of ACL injury in the nonathletic patient cohort, revision rates, and the outcomes of revision ACL reconstruction.

MATERIALS AND METHODS

856 nonathletic patients who underwent primary ACL reconstruction were included in this retrospective study. Patients were asked on phone whether they had undergone revision surgery and whether they had symptoms severe enough to seek reintervention. Clinical assessment and preoperative and postoperative International Knee Documentation Committee (IKDC) and Lysholm scoring were used to followup patients who underwent revision intervention.

RESULTS

Clinically, symptomatic revision rate was 5.9% (51 out of 856 patients), and 33 out of these 856 patients (3.9%) underwent revision ACL reconstruction. The reasons for revision were rupture of the previous graft in 21 and laxity (incompetence) of the graft in 12 patients. The mean preoperative and postoperative IKDC scores were 44.1 and 69.8, respectively, and the improvement was statistically significant (P < 0.001). The IKDC score following revision ACL reconstruction was significantly better in those patients who underwent revision <1 year following the onset of recurrent symptoms (P = 0.015). Meniscal tears were present in 47.6%, and chondral injuries were seen in 33.3% of patients. The tibial tunnel positioning was abnormal in 70% of patients. Femoral tunnel positioning was aberrant in all the patients.

CONCLUSIONS

The revision rate of primary ACL reconstruction of 5.9% in nonathletes and revision ACL reconstruction rate of 3.9% are similar to the reported revision rates of 2.9%-5.8% in athletic patients. Similar to athletes, suboptimal tunnel placement is the major contributor to failure in nonathletes also.

Preoperative Ultrasound Evaluation of the Semitendinosus Tendon for Anterior Cruciate Ligament Reconstruction

BACKGROUND

Adequate graft size and length are crucial factors that correlate with improved outcomes after anterior cruciate ligament reconstruction with a semitendinosus (ST) tendon autograft alone. Anthropometric parameters could be used as predictors of graft measurements but they have shown imprecise correlation in some patients.

PURPOSE

To evaluate the accuracy of ultrasound (US) for the preoperative evaluation of ST graft size and length.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 3.

METHODS

A total of 40 patients were included in this study. Patient sex, age, anthropometric parameters, and preoperative US measurements were recorded. After the ST tendons were harvested, their lengths as well as the diameters of the 4-strand ST grafts were recorded. Correlations between patient US measurements were analyzed. Inadequate ST graft length was defined at <28 cm, and inadequate 4-strand ST graft diameter was defined at <8 mm.

RESULTS

The prevalence of patients with an ST graft length <28 cm was 47.5%, and the prevalence of patients with a 4-strand ST graft diameter <8 mm was 42.5%. US measurements had a strong, significant correlation with the ST graft length (P < .001) and a moderate correlation with the 4-strand ST graft diameter (P < .001). Absolute agreement between the preoperative US measurement of ST graft length and the intraoperative ST graft length showed good reliability (ICC_2,1 = 0.825). The cross-sectional area (CSA) of the ST tendon at the knee joint level by US showed a weak correlation (r = 0.207) with the 4-strand ST graft diameter (P = .200). A CSA of 16 mm² measured by US could be used to predict a 4-strand ST graft diameter ≥8 mm, with a sensitivity of 73.9% and specificity of 76.5%.

CONCLUSION

Preoperative US measurements of ST tendons had a strong correlation with intraoperative ST graft length and provided good sensitivity to detect a 4-strand ST graft diameter ≥8 mm. All other anthropometric parameters showed a weak to moderate correlation with ST graft length and size.

Advanced Patellar Tendinopathy Is Associated With Increased Rates of Bone-Patellar Tendon-Bone Autograft Failure at Early Follow-up After Anterior Cruciate Ligament Reconstruction

Background

Revision anterior cruciate ligament (ACL) reconstruction can be potentially devastating for a patient. As such, it is important to identify prognostic factors that place patients at an increased risk for graft failure. There are no data on the effects of patellar tendinopathy on failure of ACL reconstruction when using a bone-patellar tendon-bone (BPTB) autograft.

Purpose/Hypothesis

The purpose of this study was to investigate the association of patellar tendinopathy with the risk of graft failure in primary ACL reconstruction when using a BPTB autograft. The hypothesis was that patellar tendinopathy would result in higher rates of graft failure when using a BPTB autograft for primary ACL reconstruction.

Study Design

Cohort study; Level of evidence, 3.

Methods

All patients undergoing ACL reconstruction at a single institution from 2005 to 2015 were examined. A total of 168 patients undergoing primary ACL reconstruction with a BPTB autograft were identified. Patients' magnetic resonance imaging scans were reviewed for the presence and grade of patellar tendinopathy by 2 musculoskeletal fellowship-trained radiologists; both were blinded to the aim of the study, patient demographics, surgical details, and outcomes. Patients were divided into 2 groups: failure (defined as presence of symptomatic laxity or graft insufficiency) and success of the ACL graft. Statistical analyses were run to examine the association of patellar tendinopathy with failure of ACL reconstruction using a BPTB autograft.

Results

At a mean follow-up of 18 months, there were 7 (4.2%) patients with graft failure. Moderate or severe patellar tendinopathy was associated with ACL graft failure (P = .011). Age, sex, and side of reconstruction were not associated with the risk of graft failure, although the majority of patients who failed were younger than 20 years. The use of patellar tendons with moderate to severe tendinopathy was associated with a relative risk of ruptures of 6.1 (95% CI, 1.37-27.34) as compared with autograft tendons without tendinopathy.

Conclusion

Moderate or severe patellar tendinopathy significantly increases the risk of graft failure when using a BPTB autograft for primary ACL reconstruction. Patellar tendinopathy should be considered when determining the optimal graft choice for patients undergoing primary ACL reconstruction with autograft tendons.

Single-stage versus two-stage revision anterior cruciate ligament reconstruction: a systematic review

Importance

Despite advances in surgical techniques and postoperative rehabilitation, long-term anterior cruciate ligament (ACL) graft rupture rate remains high. The increasing number of primary ACL reconstructions in an ageing population will lead to increasing revision reconstructions. Revision cases may have higher failure rates and worse patient-reported outcomes compared with primaries. While two-stage revisions may be indicated in certain complex cases, whether this is comparatively equivalent or even superior to revisions done in a single stage would assist preoperative planning.

Objective

The objective of this systematic review was to analyse and compare patient-reported outcomes and failure rate of single-stage versus two-stage revision ACL reconstruction.

Evidence review

Using PubMed, MEDLINE Complete and Ovid MEDLINE databases, a review was performed using Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines to identify level I–IV outcomes of revision ACL reconstruction with a minimum follow-up of 24 months.

Findings

Three studies reported outcomes of two-stage revisions with mean follow-up of 61.6 months, while 21 studies reported single-stage revisions with mean follow-up of 47.4 months. Pooled rate of two-stage revisions was 3.1% compared with 6.8% in single-stage (p=0.068). Clinical failure was reported in 5.1% of 79 two-stage patients compared with 13.8% of 533 single-stage patients (p<0.05). Within the single-stage cohort, there was a greater clinical failure rate (+8.7%, p<0.05) for patients with less than 48 months follow-up. Those with > 48 months follow-up had a higher rerupture rate (+5%, p<0.05) and a significantly greater sum of squared deviations (p<0.05) compared with those with < 48 months follow-up. Patient-reported outcomes have demonstrated two-stage revision patients with higher IKDC A and B scores than single-stage.

Conclusions and relevance

Although two-stage revisions may be performed in more complex cases, there are limited short-term data available regarding their outcomes. Two-stage revisions demonstrated comparable clinical outcomes and lower rate of revision surgery and clinical failure compared with single-stage revisions. Studies with shorter follow-up (24–48 months) showed higher clinical failure rates. Those with longer follow-up (>48 months) showed higher graft rerupture rates. The decision to perform staged reconstruction should made on whether adequate tunnel placement and fixation can be established in a single setting.

Level of evidence

Level IV.

A Narrative Review of Four Different New Techniques in Primary Anterior Cruciate Ligament Repair: "Back to the Future" or Another Trend?

Recently, four different operative techniques, referring to the primary anterior cruciate ligament (ACL) repair, were described. These are the dynamic intraligamentary stabilization (DIS) with Ligamys™, the Bridge-enhanced repair (BEAR), the use of internal brace, and the refixation with suture anchors. The purpose of this study was to assess the already-published, clinical, and pre-clinical results of those techniques. A literature review was conducted and implemented by three independent researchers. Inclusion criteria were clinical or cadaveric or animal studies about patients suffering from ACL rupture, who were treated with one of those four different arthroscopic techniques of primary ACL repair. There were 10 clinical trials dealing with the different techniques of primary ACL repair and 12 cadaveric or animal studies. The majority of the published clinical trials investigated the dynamic intraligamentary stabilization (DIS), while only four studies referred to the three other surgical techniques. Most of the clinical trials suggested that primary ACL repair should be done during the first 14–21 days after a proximal ACL rupture and not later. Further clinical evidence is needed for the techniques of bridge-enhanced ACL repair, internal brace, and suture anchors ACL refixation in order to support the animal and cadaveric biomechanical studies. Till now, the existing clinical trials were not enough to establish the use of those techniques in the ACL-ruptured patients. On the contrary, the Dynamic intraligamentary stabilization with Ligamys™ device demonstrated very promising results in different types of clinical studies.

To MOON and Back: Lessons Learned and Experience Gained Along the Way

This article highlights the Multicenter Orthopedic Outcomes Network (MOON) study of anterior cruciate ligament reconstruction, from its inception in 1991 to the follow-on studies in progress currently. Lessons learned throughout the process are emphasized.

The effects of varying frequency and duration of mechanical stimulation on a tissue-engineered tendon construct

Decellularized, discarded human tissues, such as the human umbilical vein, have been widely utilized for tissue engineering applications, including tendon grafts. When recellularized, such natural scaffolds are cultured in 3D dynamic culture environments (bioreactor systems). For tendon tissue-engineered grafts, such systems often employ oscillatory mechanical stimulation in the form uniaxial tensile strain. The three main parameters of such stimulation are frequency, duration, and force. In this study we investigated the effects of changing the duration (0.5, 1, and 2 h/day) and frequency (0.5, 1, 2 cycles/min) of stimulation of a human umbilical vein seeded with mesenchymal stem cells cultured for up to 7 days. Strain of the construct was held constant at 2%. The highest proliferation rates were observed in the 0.5 h/day duration and 1 cycle/min frequency (203% increase) with a close second being 1 h/day and 1 cycle/min frequency (170% increase). Static cultures along with a 2 cycles/min frequency and a 2 h/day duration of stretching did not increase cellular proliferation significantly. Extracellular matrix quality and alignment of the construct fibers had a direct relation to cellularity and those groups with the highest cellularity improved the most. Gene expression indicated cellular activity consistent with tendon-like tissue remodeling. In addition, scleraxis, tenascin-C, and tenomodulin were upregulated in certain groups after 7 days, with osteoblast, chondrocyte, and adipocyte phenotypes depressed. The stimulation parameters investigated in this study indicated that slower frequencies and shorter durations were best for construct quality in early stage cultures.

Comparison of Return to Pre-Injury Sport After 10 mm Size Bone-Patellar Tendon-Bone (BPTB) versus 8 mm Hamstring Anterior Cruciate Ligament Reconstruction: A Retrospective Study with a Two-Year Follow-Up

Background

The aim of this study was to evaluate the reconstruction of a torn anterior cruciate ligament (ACL) with 10 mm diameter BPTB (bone-patellar tendon-bone) autograft versus 8 mm HT (hamstring tendon) autografts, to compare the ability to restore pre-injury sports activities and reduce revision risk after these procedures.

Material/Methods

A prospective clinical review was performed to compare results of patients who underwent primary anatomical ACLR with 10 mm BPTB autografts with patients who underwent 8 mm diameter HT autografts, between January 2011 and January 2014.

Results

There were 183 patients evaluated: the 8 mm HT group showed statistically significant higher knee laxity values compared to the 10 mm BPTB group (p=0.042), and significant difference were detected in subjective International Knee Documentation Committee (IKDC) evaluation scores; the average subjective IKDC evaluations after two-year follow-up in the HT group was 88.45±2.8 versus 89.24±2.5 in BPTB group (p=0.047). In the evaluation of the IKDC objective protocol, results were excellent and good in 83 patients (94.3%) after BPTB and in 78 patients (82%) after HT ACLR (p<0.05). The average score on the Tegner activity scale in the HT group decreased from 6.5 at pre-injury to 5.8 at two-year follow-up (p<0.001) and from 6.7 at pre-injury to 6.5 at two-year follow-up in the BPTB group (p=0.4). The ability to restore pre-injury sports activities was higher in the BPTB group (6.5) versus the HT group (5.8) (p<0.001). Revision was required for two patients (2.2%) in the BPTB group compared with 14 patients (14.7%) in the HT group (p<0.05).

Conclusions

Smaller HT graft size was a predictor of higher knee laxity and greater revision risk at two-year post primary ACL reconstruction. Larger diameter BPTB ACL grafts had a better ability to restore knee stability and greater ability to restore pre-injury sports activities.

Changes in gait pattern and early functional results after ACL repair are comparable to those of ACL reconstruction

PURPOSE

Dynamic intraligamentary stabilization (DIS) has been introduced as a new technique to repair the torn anterior cruciate ligament (ACL) and to restore knee joint kinematics after an acute ACL tear. Aim of the present study was to compare the early post-operative activity, restoration of gait pattern and functional results after DIS in comparison with primary ACL reconstruction (ACLR) for acute ACL tears. It was hypothesized that functional results, post-operative activity and changes in gait pattern after DIS are comparable to those after ACLR.

METHODS

Sixty patients with acute ACL tears were included in this study and underwent either DIS or ACLR with an anatomic semitendinosus autograft in a randomized manner. Patients were equipped with an accelerometric step counter for the first 6 weeks after surgery in order to monitor their early post-operative activity. 3D gait analysis was performed at 6 weeks and 6 months after surgery. Temporal-spatial, kinematic and kinetic parameters were extracted and averaged for each subject. Functional results were recorded at 6 weeks, 6 months and 12 months after surgery using the Tegner activity scale, International Knee Documentation Committee score and Lysholm score.

RESULTS

Patients who underwent DIS showed an increased early post-operative activity with significant differences at week 2 and 3 (p = 0.0241 and 0.0220). No significant differences between groups were found for knee kinematic and kinetic parameters or the functional scores at any time of the follow-up. Furthermore, the difference in anterior tibial translation was not significantly different between the two groups (n.s.).

CONCLUSION

Early functional results and changes in gait pattern after DIS are comparable to those of primary ACLR. Therefore, ACL repair may be an alternative to ACLR in this cohort of patients.

LEVEL OF EVIDENCE

I.

Patient satisfaction with health is substantially improved following ACL reconstruction

PURPOSE

To prospectively monitor health-related quality of life and return to work after arthroscopic anterior cruciate ligament (ACL) reconstruction in patients with isolated ACL tears.

METHODS

Sixty consecutive patients with isolated ACL tears who underwent arthroscopic ACL reconstruction were prospectively monitored using the "Questions on Life Satisfaction Modules" (FLZ^M) and "Short-Form 12 (SF-12)" quality-of-life outcome measures. The Lysholm score and Tegner activity index were used as functional outcome measures. Additionally, return to work (months) together with level of physical workload was analysed. Outcome measures were assessed the day before surgery and at 6, 12 weeks and 6, 12, and 24 months post-operatively. Quality-of-life outcomes were correlated with functional outcome scores.

RESULTS

Satisfaction with health (FLZ^M) significantly improved within the first 2 years (p < 0.05), and the physical component scale (SF12) showed a significantly higher score after 3, 6, 12 and 24 months as compared with preoperative values (p < 0.05). "General life satisfaction (FLZ^M)" was initially decreased at 6 weeks (p < 0.05) but increased during the further follow-up period, reaching a score not significantly different from preoperative values. Mean Lysholm score improved from 66 preoperatively to 89 post-operatively (p < 0.05) and the median Tegner activity index improved from four to six points (p < 0.05) at final follow-up. Mean time to return to work was 7 weeks (range 1-34 weeks), and it strongly depended on physical workload. A positive correlation between quality of life and functional outcome (Lysholm score) was observed.

CONCLUSION

General life satisfaction is impaired during the early post-operative course, but returns to preoperative values after 2 years. Satisfaction with health reaches higher values after 6, 12 and 24 months post-operatively, and the SF-12 physical component scale was seen to improve during the follow-up period. Improved functional outcomes were observed to correlate with quality-of-life measurements. Thus, patients can preoperatively be informed that they will benefit from ACL reconstruction in terms of an improved knee function and satisfaction with health. Heavy physical workload must be considered as a risk factor for prolonged time lost to return to work. These patients have to be identified and informed about realistic expectations.

LEVEL OF EVIDENCE

II.

Proprioceptive Changes in Bilateral Knee Joints Following Unilateral Anterior Cruciate Ligament Injury in Cynomolgus Monkeys

BACKGROUND The anterior cruciate ligament (ACL) is one of the most important structures maintaining stability of knee joints, and the proprioception of the ACL plays a key role in it. If the ACL is injured in the unilateral knee joint, it changes nerve electrophysiology, morphology, and quantity of the proprioceptors in the bilateral ACL. The aim of this study was to explore the proprioceptive changes in the bilateral knee joints following unilateral ACL injury, and to provide a theoretical foundation and ideas for clinical treatment. MATERIAL AND METHODS Nine normal cynomolgus monkeys were chosen and used to developed a model of unilateral ACL injury, and 3 monkeys without modeling were used as blank control. At the 4th, 8th, and 12th weeks, the changes in ACL nerves were inspected using electrophysiology [somatosensory evoked potentials (SEPs) and motor nerve conduction velocity (MCV)], and the changes of morphology and quantity of the proprioceptors in ACL were observed and measured under gold chloride staining. RESULTS On the injured and contralateral knee joints, the incubations were extended and the amplitudes were decreased over time. In addition, with the extension of time, the total number of proprioceptors in the ACL decreased, and the variable number of proprioceptors in the ACL increased. CONCLUSIONS ACL injury leads to attenuation of proprioception on the injured side, and also leads to the attenuation of proprioception on the contralateral side, and there is a tendency could get worse over time.

Complications following harvesting of patellar tendon or hamstring tendon grafts for anterior cruciate ligament reconstruction: Systematic review of literature

Anterior cruciate ligament (ACL) reconstruction can be performed with an autograft, which is most often harvested from the patient's hamstring tendon (HT) or patellar tendon (PT). However, autograft harvesting leads to morbidity that is by no means insignificant. A systematic review of literature was performed to define the incidence of complications related to graft harvesting and the methods to prevent these complications. In March 2017, a systemic review of literature was performed using the keywords"harvesting", "harvest", "morbidity", "complication", "cruciate ligament". No time limit was applied. The studies had to be written in French or English with their abstract available online. This initial search based on the title and abstract identified 133 articles. Two independent observers analyzed each article entirely, including the references. In all, 36 articles were retained. The main complication of HT harvesting was sensory deficit because of damage to the infrapatellar branches of the saphenous nerve. This complication occurred in 39.7% to 88% of patients. This risk can be reduced by using a horizontal or oblique incision. The main complication following PT harvesting is anterior knee pain, reported in up to 46% of patients. There are substantial numbers of short-, medium- and long-term complications related to the harvesting of the two main ACL autografts. Effective means of prevention exist to reduce the risk of these complications.

LEVEL OF EVIDENCE

II Systematic review of literature.

Change in Anterior Cruciate Ligament Graft Choice and Outcomes Over Time

PURPOSE

To analyze failure rate in 2-year increments to determine if graft choice changed over time and graft failure rate.

METHODS

A prospective 2002-2008 database was used to identify risk factors for anterior cruciate ligament (ACL) retear. Subjects who had primary ACL retear with no history of contralateral surgery and 2-year follow-up were included. Subjects who underwent a multiligament reconstruction were excluded. Graft type, age, sex, smoking status, body mass index, Marx activity level at index surgery, medial and lateral meniscus status at time of ACL retear, sport played after ACL reconstruction, and clinical site were evaluated. Analysis was repeated using 2002-2003 (early) and 2007-2008 (late) 2-year databases. Analysis of variance with post hoc analysis was performed to detect significant differences in age and Marx score by graft type over time.

RESULTS

Two-year follow-up for graft failure was obtained on 2,497 of 2,692 (93%) subjects. There were 112 of 2,497 (4.5%) ACL retears identified at 2-year follow-up. The only predictor that changed between early/late periods was allograft use. Allograft odds ratio decreased from 13.1 to 9.5 (P < .01). Allografts were used in older patients (31-40 years) and with lower Marx scores (10-8) from early to late periods. The mean age of subjects who received bone-patellar tendon-bone autografts did not significantly change over time (22.8-23.5). The mean age of subjects who received hamstring autografts fell (27.9-25.5). The mean age of subjects who received allografts rose significantly (31.3-39.8, P < .01). The mean Marx score of subjects who received bone-patellar tendon-bone and hamstring autografts did not significantly change over time. The mean Marx score of subjects who received allografts decreased significantly (P < .01).

CONCLUSIONS

After early recognition, allograft use in young active patients was a risk factor for retear; graft choice by surgeons changed in the late period to use of allografts in older and less-active patients, which correlated with a significant decrease in retear risk.

LEVEL OF EVIDENCE

Level III, case control study.

Clinical and arthroscopic outcome of single bundle anterior cruciate ligament reconstruction: Comparison of remnant preservation versus conventional technique

BACKGROUND

The purpose of this study was to compare the clinical outcomes and second-look arthroscopic findings of remnant preservation technique with those of conventional anterior cruciate ligament (ACL) reconstruction in single bundle ACL reconstructions.

METHODS

One hundred sixty two consecutive patients underwent ACL reconstruction by one surgeon, with 93 patients receiving remnant preservation technique (Group A) and 69 patients receiving conventional ACL reconstruction (Group B). The mean follow-up was 15months. Clinical outcomes were assessed using Lysholm scores and the International Knee Documentation Committee form (IKDC form) evaluation. Post-operative knee stability was evaluated through manual knee laxity evaluation, pivot-shift test, and a Telos device.

RESULTS

Differences in post-operative stability (manual knee laxity, pivot shift test and Telos device) were not significant between the groups (p=0.681, p=0.610, p=0.696). And also no significant differences were noted with respect to the IKDC form and the latest Lysholm scores. But in the second-look arthroscopic findings, synovial coverage was confirmed to be excellent in 36% (22/61) of Group A patients and 23% (7/30) of Group B patients.

CONCLUSIONS

ACL reconstruction with both techniques was found to result in acceptable stability, clinical outcomes and second-look arthroscopic findings. With regard to synovial coverage, the remnant reservation techniques were found to be superior to conventional ACL reconstruction.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

The Role of an Extra-Articular Tenodesis in Revision of Anterior Cruciate Ligament Reconstruction

Patients who present for anterior cruciate ligament (ACL) revision with a high-grade pivot shift at the time of an index ACL revision procedure and subsequent reconstruction failure or a high-grade pivot shift at revision surgery, patients with generalized joint laxity, and those requiring softs tissue grafts should be considered candidates for lateral tenodesis to supplement intraarticular graft revision. Although there is no consensus regarding the optimal lateral tenodesis technique, due to the tibial positioning associated with tensioning and fixation of extra-articular procedures, a lateral tenodesis should not be used in patients with posterolateral corner injuries or lateral compartment articular disease.

Isolated ACL versus multiple knee ligament injury: associations with patient characteristics, cartilage status, and meniscal tears identified during ACL reconstruction

OBJECTIVES

The objectives of this study were to determine (1) if patients undergoing reconstruction of an isolated anterior cruciate ligament (ACL) tear had different characteristics (age, gender, body mass index [BMI]) than patients undergoing ACL reconstruction (ACLR) with multiple knee ligament (MKL) tears and (2) whether there was a difference in prevalence of articular cartilage injury and meniscus tears between these two groups.

METHODS

Patients undergoing primary ACLR between February 2005 and June 2013 were identified through an ACLR registry. Patients were grouped by whether they had an isolated ACL tear or an ACL tear associated with another knee ligament tear. The study cohort was analyzed to identify differences in patient characteristics and cartilage/meniscus injury patterns between the groups.

RESULTS

Of the 21,377 ACLR cases enrolled in the registry during the study period, 2.5% (n = 549) had MKL tears. The MKL group had more males (73.2% vs. 62.8%, p < 0.001) than the isolated ACL group. The MKL group also had a higher percentage of patients with a BMI greater than 30 (31.1% vs. 22.7%, p = 0.0002). When adjusting for these variables, any articular cartilage injury was equal in the two groups (OR = 1.01, CI 0.82-1.25, p = 0.922), while medial femoral condyle injury was less common in the MKL group (OR = 0.73, CI = 0.56-0.07, p = 0.28). The likelihood of any meniscus tear was lower in the MKL group (OR = 0.56, CI = 0.47-0.67, p < 0.001) as was the likelihood of medial meniscus tears (OR = 0.53, CI = 0.44-0.65, p < 0.001).

CONCLUSIONS

When comparing patients with MKL tears versus isolated ACL tears at ACLR, there was a higher percentage of males and patients with BMI over 30 in the MKL group. Medial femoral condyle articular cartilage injury, any meniscus tear, and medial meniscus tears were less common in patients with MKL injury compared to patients with isolated ACL tears.

Web-based survey results: surgeon practice patterns in Italy regarding anterior cruciate ligament reconstruction and rehabilitation

PURPOSE

The aim of this study was to report Italian orthopaedic surgeons' management of choice for ACL reconstruction and rehabilitation, and to compare surgical applications and rehabilitation approaches of Italian surgeons to the current approaches of "ACL Study Group". A secondary purpose was to compare the preferences of subgroup based on graft choice, surgical techniques and experience.

METHODS

A web-based survey was developed to investigate the attitudes of members of a national association specialized in sports traumatology and knee surgery (SIGASCOT) regarding surgical techniques, routine post-operative applications, rehabilitation approaches and starting time of specific activities and exercises following ACL reconstruction.

RESULTS

The response rate was 17 % (131 questionnaires). The most popular graft type was hamstring tendon (81 % in male patients, and 91 % in female patients). The rate of continuous passive motion use was 55 %. Half surgeons routinely used a brace (49 %), usually a hinged brace. In total, 33.0 % of surgeons allowed patients to load the operated knee as much as tolerated within the first 2 weeks. Fifty-nine per cent of surgeons did not limit full flexion within the first 2 weeks. Most surgeons advise to wait until 4 months or more (97 %) for return to sports not requiring contact, and 6 months or more for full-contact sport (86 %).

CONCLUSIONS

This survey demonstrates clear trends in the practice of ACL reconstruction and rehabilitation in Italy. The data obtained from the SIGASCOT members revealed a more conservative approach when compared to the current approaches of "ACL Study Group".

LEVEL OF EVIDENCE

Cross-sectional survey, Level III.

Increased Risk of Revision After Anterior Cruciate Ligament Reconstruction With Soft Tissue Allografts Compared With Autografts: Graft Processing and Time Make a Difference

BACKGROUND

The optimal graft for anterior cruciate ligament reconstruction (ACLR) remains controversial.

PURPOSE

To compare the risk of aseptic revision between bone-patellar tendon-bone (BPTB) autografts, hamstring autografts, and soft tissue allografts.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Prospectively collected ACLR cases reconstructed with BPTB autografts, hamstring autografts, and soft tissue allografts were identified using the Kaiser Permanente ACLR Registry. Aseptic revision was the endpoint. The type of graft and allograft processing method (nonprocessed, <1.8-Mrad irradiation with and without chemical processing [Allowash or AlloTrue], ≥1.8-Mrad irradiation with and without chemical processing, and chemical processing alone [BioCleanse]) were the exposures evaluated. Analyses were adjusted for age, sex, and race. Kaplan-Meier curves and Cox proportional hazards models were employed.

RESULTS

The cohort included 14,015 cases: there were 8924 (63.7%) male patients, there were 6397 (45.6%) white patients, 4557 (32.5%) ACLRs used BPTB autografts, 3751 ACLRs (26.8%) used soft tissue allografts, and 5707 (40.7%) ACLRs used hamstring autografts. The median age was 34.6 years for soft tissue allografts, 24.3 years for hamstring autografts, and 22.0 years for BPTB autografts. The crude nonadjusted revision rates were 85 (1.9%) in BPTB autograft cases, 132 (2.3%) in hamstring autograft cases, and 83 (2.2%) in soft tissue allograft cases. After adjusting for age, sex, and race, compared with hamstring autografts, a higher risk of revision was found with allografts with ≥1.8 Mrad without chemical processing after 2.5 years (hazard ratio [HR], 3.88; 95% CI, 1.48-10.12) and ≥1.8 Mrad with chemical processing after 1 year (HR, 3.43; 95% CI, 1.58-7.47) and with BioCleanse processed grafts at any time point (HR, 3.02; 95% CI, 1.40-6.50). Nonprocessed allografts and those irradiated with <1.8 Mrad with or without chemical processing were not found to have a different risk of revision compared with hamstring autografts. Compared with BPTB autografts, a higher risk of revision was seen with hamstring autografts (HR, 1.51; 95% CI, 1.15-1.99) and BioCleanse processed allografts (HR, 4.67; 95% CI, 2.15-10.16). Allografts irradiated with <1.8 Mrad with chemical processing (Allowash or AlloTrue) (HR, 2.19; 95% CI, 1.42-3.38) and without chemical processing (HR, 2.31; 95% CI, 1.40-3.82) had a higher risk of revision, as did allografts with ≥1.8 Mrad without chemical processing after 2 years (HR, 6.30; 95% CI, 3.18-12.48) and ≥1.8 Mrad with chemical processing (Allowash or AlloTrue) after 1 year (HR, 5.03; 95% CI, 2.30-11.00) compared with BPTB autografts. Nonprocessed allografts did not have a higher risk of revision compared with autografts. With the numbers available, direct comparisons between the specific allograft processing methods were not possible.

CONCLUSION

When soft tissue allografts are used for ACLR, processing and time from surgery affect the risk of revision. Tissue processing has a significant effect on the risk of revision surgery, which is most profound with more highly processed grafts and increases with increasing follow-up time. Surgeons and patients need to be aware of the increased risks of revision with the various soft tissue allografts used for ACLR.

Anatomic Anterior Cruciate Ligament Reconstruction via Independent Tunnel Drilling: A Systematic Review of Randomized Controlled Trials Comparing Patellar Tendon and Hamstring Autografts

PURPOSE

To collect the highest level of evidence comparing anatomic anterior cruciate ligament (ACL) reconstruction via independent tunnel drilling using bone-patellar tendon-bone (BTB) and hamstring tendon (HT) autografts in terms of clinical outcome and failure rate.

METHODS

We performed a systematic review of clinical trials that randomized patients to ACL reconstruction with either BTB or HT autografts with a minimum 2-year follow-up. Only trials using independent tunnel drilling, including outside-in and anteromedial portal techniques, for both autografts were eligible for inclusion, whereas all transtibial studies were excluded. Study design, demographics, surgical technique, rehabilitation protocol, and clinical outcomes were compiled. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Quality assessment was performed using the Coleman Methodological Scale (CMS).

RESULTS

Six published studies reporting on 5 randomized controlled trials (RCTs) met the inclusion criteria. No study reported a difference in rerupture rate between BTB and HT. BTB-reconstructed knees experienced a greater incidence of anterior knee pain or crepitus in 2/7 trials and radiographic evidence of degenerative change in 3/7 trials. HT-reconstructed knees had increased instrumented laxity in 2/7 trials and less knee flexion strength postoperatively.

CONCLUSIONS

This study collects all available Level I and II evidence for anatomic ACL reconstruction using BTB and HT grafts. According to the data presented in these studies, clinical outcome scores and failure rates showed no differences for anatomic reconstruction using either autograft. However, in some studies, BTB-reconstructed knees experienced a greater incidence of anterior knee pain and radiographic evidence of degenerative change, and in others, HT-reconstructed knees had increased laxity and less knee flexion strength. In our opinion, both BTB and HT autografts remain valid options for ACL reconstruction when using anatomic drilling techniques, providing a stable knee with reliable return to activity.

LEVEL OF EVIDENCE

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

Increased Risk of Revision After Anterior Cruciate Ligament Reconstruction With Bone-Patellar Tendon-Bone Allografts Compared With Autografts

BACKGROUND

The use of allograft tissue for anterior cruciate ligament reconstruction (ACLR) remains controversial.

PURPOSE

To compare the risk of aseptic revision between bone-patellar tendon-bone (BPTB) autografts and BPTB allografts.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A retrospective cohort study of prospectively collected data was conducted using the Kaiser Permanente ACLR Registry. A cohort of patients who underwent primary unilateral ACLR with BPTB autografts and BPTB allografts was identified. Aseptic revision was the endpoint. The type of graft and allograft processing method (nonprocessed, <1.8-Mrad, and ≥1.8-Mrad irradiation) were the exposures of interest evaluated. Age (≤21 and ≥22 years) was evaluated as an effect modifier. Analyses were adjusted for age, sex, and race. Kaplan-Meier curves and Cox proportional hazards models were employed. Hazard ratios (HRs) and 95% CIs are provided.

RESULTS

The BPTB cohort consisted of 5586 patients: 3783 (67.7%) were male, 2359 (42.2%) were white, 1029 (18.4%) had allografts (nonprocessed: 155; <1.8 Mrad: 525; ≥1.8 Mrad: 288), and 4557 (81.6%) had autografts. The median age was 34.9 years (interquartile range [IQR], 25.4-44.0) for allograft cases and 22.0 years (IQR, 17.6-30.0) for autograft cases. The estimated cumulative revision rate at 2 years was 4.1% (95% CI, 2.9%-5.9%) for allografts and 1.7% (95% CI, 1.3%-2.2%) for autografts. BPTB allografts had a significantly higher adjusted risk of revision than BPTB autografts (HR, 4.54; 95% CI, 3.03-6.79; P < .001). This higher risk of revision was consistent with all allograft processing methods when compared with autografts and was also consistently higher in patients with allografts regardless of age.

CONCLUSION

When BPTB allograft tissue was used for ACLR, an overall 4.54 times adjusted higher risk of revision was observed compared with surgery performed with a BPTB autograft. Whether the tissue was irradiated with either high- or low-dose radiation, chemically processed, or not processed at all made little difference in the risk of revision. The differences in the revision risk were also consistent in younger and older patients. Surgeons and patients should be aware of the increased risk of revision when a BPTB allograft is used for ACLR.

Proteomic differences between native and tissue-engineered tendon and ligament

Tendons and ligaments (T/Ls) play key roles in the musculoskeletal system, but they are susceptible to traumatic or age‐related rupture, leading to severe morbidity as well as increased susceptibility to degenerative joint diseases such as osteoarthritis. Tissue engineering represents an attractive therapeutic approach to treating T/L injury but it is hampered by our poor understanding of the defining characteristics of the two tissues. The present study aimed to determine differences in the proteomic profile between native T/Ls and tissue engineered (TE) T/L constructs. The canine long digital extensor tendon and anterior cruciate ligament were analyzed along with 3D TE fibrin‐based constructs created from their cells. Native tendon and ligament differed in their content of key structural proteins, with the ligament being more abundant in fibrocartilaginous proteins. 3D T/L TE constructs contained less extracellular matrix (ECM) proteins and had a greater proportion of cellular‐associated proteins than native tissue, corresponding to their low collagen and high DNA content. Constructs were able to recapitulate native T/L tissue characteristics particularly with regard to ECM proteins. However, 3D T/L TE constructs had similar ECM and cellular protein compositions indicating that cell source may not be an important factor for T/L tissue engineering.

The biomechanical effects of graft rotation on ACL reconstruction tunnel mismatch

PURPOSE

Bone block protrusion out of the tibial tunnel due to a relatively long graft is a common complication in anterior cruciate ligament surgical reconstruction with a patellar tendon. One possible solution is to shorten the patellar tendon graft already fixed in the femur by applying external rotation. This study aimed to evaluate the degree of shortening and biomechanical changes in porcine patellar grafts subjected to relatively higher degrees of rotation. Data obtained with rotations of 0°, 540°, 720°, and 900° were compared.

METHODS

Forty patellar porcine ligaments were subjected to biomechanical tests of degree of shortening, modulus of elasticity and maximum tension in the tendon before rupture. Tests were conducted using a universal mechanical testing machine and a computerized system for acquiring strength and deformation data.

RESULTS

Progressive shortening of the patellar ligament occurred with rotations of 0°, 540° and 720°. However, the degree of shortening showed no statistically significant difference as rotation increased from 720° to 900°. Decreased modulus of elasticity was observed compared with the graft rotation at 0° in all groups tested, but no statistically significant differences were observed among 540°, 720° and 900°. The maximum tension of the patellar tendon showed no change before rupture, regardless of the degree of rotation.

CONCLUSIONS

Rotating the patellar tendon is an efficient method for shortening a relatively long graft; however, more biomechanical studies are necessary to recommend this technique in clinical practice owing to the resulting decrease in graft stiffness that could compromise knee stability.