The science of reconstruction of the anterior cruciate ligament

All-epiphyseal anterior cruciate ligament reconstruction yields superior sports performances than the trans-epiphyseal technique in skeletally immature patients: a systematic review

BACKGROUND

Anterior cruciate ligament (ACL) tears in skeletally immature patients are increasingly common. Evidence comparing the outcomes of all-epiphyseal versus trans-epiphyseal ACL reconstruction in skeletally immature patients is limited, and the current literature could benefit from a comprehensive systematic review. The present study compared all-epiphyseal versus trans-epiphyseal ACL reconstruction in skeletally immature patients. The outcomes of interest were to compare joint laxity, patient-reported outcome measures (PROMs), return to sport, and complications.

METHODS

This study was conducted according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. In November 2023, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Embase. No additional filters were used in the database search. All the clinical studies investigating ACL reconstruction in skeletally immature patients were accessed. Only articles that clearly stated the surgical technique (all- or trans-epiphyseal) were eligible. Only articles with a minimum of 6 months of follow-up were included. Only articles that clearly stated that surgeries were conducted in children with open physis were eligible.

RESULTS

Data from 1489 patients (1493 procedures) were collected, of which 32% (490 of 1489 patients) were female. The mean length of follow-up was 46.6 months. The mean age of the patients was 12.7 years. No difference was found in joint laxity (Table 3): positive pivot shift (P = 0.4), positive Lachman test (P = 0.3), and mean arthrometer laxity (P = 0.1). No difference was found in PROMs (Table 4): International Knee Documentation Committee (IKDC) (P = 0.3), Lysholm (P = 0.4), and Tegner (P = 0.7). The trans-epiphyseal technique was associated with a greater rate of patients unable to return to sports (1% versus 7%, P = 0.0001) and with a longer time to return to sports (7.7 versus 8.6 months, P = 0.01). Though the trans-epiphyseal technique was associated with a lower rate of return to sport, this difference was not statistically significant (P = 0.8). No difference was evidenced in the rate of patients who had reduced their league or level of sports activity (P = 0.6) or in the rate of patients who had returned to their previous league or level of sports activity (P = 0.7). No difference was found in the rate of complication: re-tear (P = 0.8), reoperation (P = 0.7), increased laxity (P = 0.9), and persistent instability sensation (P = 0.3).

CONCLUSION

Trans-epiphyseal ACL reconstruction was associated with a greater rate of patients unable to return to sport and with a longer time to return to sport compared with the all-epiphyseal technique in skeletally immature patients. Level of evidence Level III, systematic review.

Double-bundle anterior cruciate ligament reconstruction in patients aged 60 years and older

Background

This study aimed to examine the clinical outcomes of double-bundle (DB) anterior cruciate ligament (ACL) reconstruction in patients aged ≥60 years.

Methods

Anatomical DB-ACL reconstruction using hamstring tendon autografts was performed in 13 patients aged ≥60 years at our institution between June 2012 and May 2018. The patients included seven men and six women, and the mean age at surgery was 65.0 years (range, 60-73 years). The mean time from injury to surgery was 80.5 months (range, 1-480 months), and the mean follow-up time was 26.2 months (range, 24-42 months). All patients were assessed based on physical examination findings, clinical scores, Kellgren-Lawrence grades preoperatively and at the final postoperative follow-up, intraoperative meniscal or chondral lesions, and perioperative complications. Status of returning to sports for all patients was assessed at the final follow-up.

Results

The mean side-to-side differences by arthrometer improved from 4.3 mm (range, 2-8 mm) to 0.9 mm (range, 0-2 mm), and the positive pivot-shift test decreased from 100% to 8%. The mean extensor muscle strength was 93.3% (range, 74-116%) postoperatively. The mean Lysholm score improved from 71.1 (range, 27-85) to 95.2 (range, 89-100). Ten of the 13 patients (77%) returned to their pre-injury level of sports performance, and one patient (8%) returned to sports with less intensity. Intraoperatively, meniscal tears were observed in 10 patients (77%), and chondral lesions >grade 2 were observed in 11 (85%). One patient developed perioperative complications. At the final follow-up, the Kellgren-Lawrence grade worsened in only one patient. No re-injury or infection was observed, and revision surgery was not required for any patients.

Conclusions

Anatomical DB-ACL reconstruction could provide satisfactory clinical outcomes and knee function restoration in patients aged ≥60 years.

Level of evidence

A retrospective study, case series (IV).

Race and Gender Differences in Anterior Cruciate Ligament Femoral Footprint Location and Orientation: A 3D-MRI Study

OBJECTIVE

The femoral tunnel position is crucial to anatomic single-bundle anterior cruciate ligament (ACL) reconstruction, but the ideal femoral footprint position are mostly based on small-sized cadaveric studies and elderly patients with a single ethnic background. This study aimed to identify potential race- or gender-specific differences in the ACL femoral footprint location and ACL orientation, determine the correlation between the ACL orientation and the femoral footprint location.

METHODS

Magnetic resonance images (MRIs) of 90 Caucasian participants and 90 matched Chinese subjects were used for reconstruction of three-dimensional (3D) femur and tibial models. ACL footprints were sketched by several experienced orthopedic surgeons on the MRI photographs. The anatomical coordinate system was applied to reflect the ACL footprint location and orientation of scanned samples. The femoral ACL footprint locations were represented by their distance from the origin in the anteroposterior (A/P) and distal-proximal (D/P) directions. The orientation of the ACL was described with the sagittal, coronal and transverse deviation angles. The ACL orientation and femoral footprint position were compared by the two-sided t-test. Multiple regression analysis was used to study the correlation between the orientation and femoral footprint position.

RESULTS

The average femur footprint A/P position was -6.6 ± 1.6 mm in the Chinese group and -5.1 ± 2.3 mm in the Caucasian group, (p < 0.001). The average femur footprint D/P position was -2.8 ± 2.4 mm in Chinese and - 3.9 ± 2.0 mm in Caucasians, (p = 0.001). The Chinese group had a mean difference of a 1.5 mm (6.1%) more posterior and 1.1 mm (5.3%) more proximal in the position from the flexion-extension axis (FEA). And the males have a sagittal plane elevation about 4-5° higher than females in both racial groups. Furthermore, for every 1% (0.40 mm) increase in A/P and D/P values, the sagittal angle decreased by about 0.12° and 0.24°, respectively; the coronal angle decreased by about 0.10° and 0.30°, respectively. For every 1% (0.40 mm) increase in D/P value, the transverse angle increased by about 0.14°.

CONCLUSION

The significant race- and gender-specific differences in the femoral footprint and orientation of the ACL should be taken in consideration during anatomic single-bundle ACL reconstruction. Furthermore, the quantitative relationship between the ACL orientation and the footprint location might provide some reference for surgeons to develop a surgical strategy in ACL single-bundle reconstruction and revision.

Evaluation of Graft Maturation by MRI in Anterior Cruciate Ligament Reconstruction With and Without Concomitant Anterolateral Ligament Reconstruction

Background

Single-bundle anterior cruciate ligament reconstruction (SB-ACLR) with concomitant anterolateral ligament reconstruction (ALLR) has been associated with better clinical results when compared with isolated SB-ACLR. However, it is not known whether the improved outcomes are the result of the influence of concomitant ALLR on ACL graft healing.

Purpose/Hypothesis

The purpose of this study was to determine whether concomitant ALLR is associated with improved graft ligamentization after SB-ACLR. It was hypothesized that ALLR would not affect graft healing.

Study Design

Cohort study; Level of evidence, 3.

Methods

A 1 to 1 matching study was conducted on a consecutive series of 732 patients who underwent ACLR using a hamstring tendon autograft between 2007 and 2019. Patients were excluded if they had skeletal immaturity, inflammatory joint disease, multiple ligament reconstruction (other than ALLR), or a graft rupture. Patients with concomitant SB-ACLR and ALLR (SB-ACLR/ALLR) and isolated SB-ACLR were matched 1 to 1 based on age, sex, examination under anesthesia (EUA) grade 3 pivot shift, EUA grade 3 anterior drawer test, presence of graft impingement, sagittal graft angle, skeletal maturity, lack of generalized ligamentous laxity, and multiple ligamentous injury. A total of 40 matched pairs underwent postoperative magnetic resonance imaging (MRI) within the second year after surgery to assess graft ligamentization, which was measured by the signal-to-noise quotient (SNQ) of the ACL graft.

Results

The mean follow-up period was 41 months, with a 2-year follow-up rate of 80% in the SB-ACLR/ALLR group and 98% in the isolated SB-ACLR group. The mean duration between the index operation and MRI was 16.4 ± 3.4 months. No significant difference was observed in the SNQ of the ACL graft between the SB-ACLR/ALLR and SB-ACLR groups (6.9 ± 4.6 vs 5.2 ± 4.8, respectively; P = .066).

Conclusion

Study findings indicated that a concomitant ALLR at the time of hamstring tendon autograft ACLR did not affect graft healing as assessed by the SNQ of the ACL graft.

Analyzing the Quality, Reliability, and Educational Value of ACL Rehabilitation Exercises on TikTok: A Cross-Sectional Study

Background

Videos relating to rehabilitation exercises for common injuries relevant to younger populations such as anterior cruciate ligament (ACL) tear receive high view counts on social media platforms such as TikTok.

Purpose/Hypothesis

The purpose of this study was to analyze the quality, reliability, and educational value of TikTok videos among the patient population for ACL injury. It was hypothesized that TikTok videos related to ACL rehabilitation exercises would lack quality, reliability, and educational value.

Study Design

Cross-sectional study.

Methods

TikTok was queried for relevant videos using the hashtags "#ACLrehab" and "#ACLexercises." For each included video, the type of uploader (general user or health care professional) was identified. In addition, the number of views, likes, shares, comments, and favorites for each included video was recorded, and the content of each video was graded using the DISCERN (a well-validated informational analysis tool) and the ACL exercise education score (ACLEES - a custom-designed tool for the evaluation of ACL-related exercises).

Results

A total of 111 videos with 5,520,660 cumulative views were included; the median number of views per video was 9801.0 (interquartile range [IQR], 3583.0-28,000.0). Of these videos, 84 and 27 were created by the general public and health care professionals, respectively. The videos collectively received 335,577 likes, 2969 comments, 22,856 favorites, and 6142 shares, with a median of 439 (IQR, 111-1374), 10 (IQR, 2.5-25.5), 54 (IQR, 18-172.5), and 12 (IQR, 2-36), respectively. The tabulated scores for the DISCERN and ACLEES between general users and health care professionals were all statistically nonsignificant. Health care professionals had a higher percentage of videos with a "very poor" DISCERN score in comparison with the general public (66.67% vs 53.57%, respectively).

Conclusion

The overall educational value of the TikTok videos related to ACL rehabilitation exercises was very poor. Health care professionals should be aware of the broad distribution of ACL rehabilitation exercise videos that are accessible on TikTok and raise awareness of the deficiencies of the platform as a medium for educational medical-related information.

Anterior Cruciate Ligament Reconstruction Improves Functional Scores and Quality of Life in Patients Older Than 50 Years of Age

Purpose

To evaluate quality of life changes and functional outcomes of anterior cruciate ligament reconstruction in patients older than 50 years of age with anterior cruciate ligament injury.

Methods

Patients who were older than 50 years of age and had undergone anterior cruciate ligament reconstruction with single-bundle hamstring tendon auto graft surgery between January 2016 and February 2018 were identified. Preoperative Tegner activity scores, Lysholm knee scores, International Knee Documentation Committee (IKDC) 2000 scores, and Short-Form 36 scores were compared with results that were documented 1 year after surgery.

Results

A total of 35 patients were included (20 male/15 female; mean age 52 years [range 50-59 years]). Patients' preoperative mean Tegner score was 1.48. Mean Tegner score at 1-year follow-up was 3.82. Preoperative mean Lysholm score was 45.8. Postoperative mean Lysholm score was 88. Preoperative mean IKDC 2000 score was 33. Postoperative mean IKDC 2000 score was 82. All of these changes were statistically significant (P < .05). All of the parameter changes at Short Form-36 except for role limitations due to emotional problems were statistically significant.

Conclusions

Improved functional knee scores, quality of life, and psychological status were achieved at anterior cruciate ligament reconstruction in patients older than 50 years of age.

Level of Evidence

Level IV, therapeutic case series.

Reduced knee laxity and failure rate following anterior cruciate ligament reconstruction compared with repair for acute tears: a meta-analysis

BACKGROUND

Following anterior cruciate ligament (ACL) tears, both repair and reconstruction may be performed to restore joint biomechanics and proprioception. The present study compared joint laxity, patient-reported outcome measures (PROMs), and rate of failure following primary repair versus reconstruction for ACL ruptures.

METHODS

This meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pubmed, Google scholar, Embase, and Web of Science were accessed in September 2022. All the clinical investigations comparing repair versus reconstruction for primary ACL tears were accessed. Studies reporting data on multiple ligament injuries settings were not eligible.

RESULTS

Data from eight articles (708 procedures) were collected. The mean length of the follow-up was 67.3 ± 119.4 months. The mean age of the patients was 27.1 ± 5.7 years. Thirty-six percent (255 of 708 patients) were women. The mean body mass index (BMI) was 24.3 ± 1.1 kg/m². The mean time span from injury to surgery was 36.2 ± 32.3 months. There was comparability at baseline with regards to instrumental laxity, Lachman test, International Knee Document Committee (IKDC), and Tegner Scale (P > 0.1). Similarity between ACL reconstruction and repair was found in IKDC (P = 0.2) and visual analog scale (VAS) satisfaction (P = 0.7). The repair group demonstrated greater mean laxity (P = 0.0005) and greater rate of failure (P = 0.004).

CONCLUSION

ACL reconstruction may yield greater joint stability and lower rate of failure compared with surgical repair. Similarity was found in PROMs.

LEVEL OF EVIDENCE

III.

Anterior Cruciate Ligament Arthroscopic Ligamentoplasty Using the Four-Strand Hamstring Technique

In this study, we looked at the clinical outcomes of individuals who had a symptomatic torn anterior cruciate ligament and had their anterior cruciate ligament repaired using a four-strand hamstring (4SHS) tendon autograft at least two years later. This is a retrospective study of 34 cases of anterior cruciate ligament arthroscopic reconstruction using the four-strand hamstring graft, collected from Traumatology and Orthopedics at Cheikh Khalifa Hospital in Casablanca, Morocco between January 2017 and January 2021. Different surgeons performed the operations. Physical findings and functional scores were recorded before the follow-up physical examination and surgery; thus, knee radiographs have been evaluated. A six-month rehabilitation program was devised following surgery. The average age of the patients was 30 years, with a male predominance of 94%. Thirty patients (88%) reported negative pivot shift tests and the Lachman test. The average Lysholm score enhanced from 59.3 before surgery to 85.29 at the time of the assessment. Three patients (8.82%) with a positive pivot shift test had no background of extra knee damage. In comparison to the appearance on the preoperative radiographs, no proof of progressive degenerative deterioration was found on the follow-up radiographs. All of the patients, however, had tunnel extension. The tibial tunnel grew on average by 18%, while the femoral tunnel grew on average by 30%. In 88% of patients assessed at least two years after surgery, ligamentoplasty of the anterior cruciate ligament using the four-strand hamstring graft eradicated anterior tibial subluxation. The failure rate was overall 10%. The functional knee scores had greatly improved at the time of the follow-up.

Bone-patellar tendon-bone versus two- and four-strand hamstring tendon autografts for ACL reconstruction in young adults: a Bayesian network meta-analysis

Bone-patellar tendon-bone (BPTB), two- and four-strand hamstring tendon (4SHT and 2SHT, respectively) are the most common autografts used for anterior cruciate ligament (ACL) reconstruction. The present study compared BPTB, 2SHT, and 4SHT for ACL reconstruction in terms of joint laxity, patient reported outcome measures (PROMs), rate of failure and anterior knee pain (AKP). The time to return to sport and the peak torque between the autografts were also compared. Finally, prognostic factors leading to worse outcomes were also investigated. It was hypothesized that all grafts yield similar proprieties in terms of joint laxity, patient reported outcome measures (PROMs) and rate of failure, but that the BPTB autograft causes a greater rate of anterior knee pain (AKP). The literature search was conducted. All clinical trials comparing BTPB and/or 2SHT, and/or 4SHT were accessed. Grafts other than BTPB and/or 4SHT and/or 2SHT were not considered. Articles reporting outcomes of allografts or synthetic grafts were not eligible, nor were those concerning revision settings. Articles reporting ACL reconstruction in patients with multi-ligament damage were also not eligible. Data from 95,575 procedures were retrieved. The median length of follow-up was 36 months. The median age of the patients was 27.5 years. With regard to joint laxity, similarity was found in terms of Lachman and Pivot shift tests between all three autografts. The BPTB demonstrated the greatest stability in terms of instrumental laxity. BPTB demonstrated the greatest PROMs. BPTB demonstrated the greatest rate of AKP, while AKP in 2SHT and 4SHT was similar. Concerning failure, statistically significant inconsistency was found (P = 0.008). The 4SHT demonstrated the quickest return to sport, followed by BPTB, and 2SHT. There was evidence of a negative association between the time span between injury to surgery, Lysholm score (P = 0.04), and Tegner scale (P = 0.04). Furthermore, there was evidence of a weak positive association between the time span between injury to surgery and return to sport (P = 0.01). BPTB may result in lower joint laxity, greater PROMs, and greater peak flexion torque compared to 2SHT and 4SHT autografts. On the other hand, BPTB reported the lowest peak extension torque and the greatest rate of AKP. Finally, a longer time span between injury and surgery negatively influences outcome.

The influence of ruptured scar pattern of human anterior cruciate ligament remnant tissue on tendon-bone healing in vivo

The purpose of this study was to determine whether the transplantation of human cells from a non-reattached injured anterior cruciate ligament (ACL) remnant could enhance tendon-bone healing. Human ACL remnant tissue was classified into two groups based on the morphologic pattern as per Crain's classification: (1) non-reattachment group (Crain Ⅳ) and (2) reattachment group (Crain Ⅰ-Ⅲ). Seventy-five 10-week-old immunodeficient rats underwent ACL reconstruction followed by intracapsular administration of one of the following: (1) ACL-derived cells from the non-reattached remnant (non-reattachment group) (n = 5), (2) ACL-derived cells from the reattached tissue (reattachment group) (n = 5), or (3) phosphate-buffered saline (PBS) only (PBS group) (n = 5). Histological (Weeks 2, 4, and 8), immunohistochemical (Week 2), radiographic (Weeks 0, 2, 4, and 8), and biomechanical (Week 8) assessments were performed. Histological evaluation showed high and early healing, induction of endochondral ossification-like integration, and mature bone ingrowth at Week 4 in the non-reattachment group. Microcomputed tomography at Week 4 showed that the tibial bone tunnels in the non-reattachment group were significantly reduced compared to those in the reattachment and PBS groups. Moreover, biomechanical testing showed that ultimate load-to-failure in the non-reattachment group tended to be larger than that in the reattachment group, though not statistically significant. The enhanced healing potential in the non-reattachment group was explained by the increase in intrinsic angiogenesis/osteogenesis. In the subacute phase, the ACL-derived cells with the non-reattached morphologic pattern showed greater and earlier tendon bone healing compared with the cells obtained from the reattached morphologic pattern.

Advanced Gene Therapy Strategies for the Repair of ACL Injuries

The anterior cruciate ligament (ACL), the principal ligament for stabilization of the knee, is highly predisposed to injury in the human population. As a result of its poor intrinsic healing capacities, surgical intervention is generally necessary to repair ACL lesions, yet the outcomes are never fully satisfactory in terms of long-lasting, complete, and safe repair. Gene therapy, based on the transfer of therapeutic genetic sequences via a gene vector, is a potent tool to durably and adeptly enhance the processes of ACL repair and has been reported for its workability in various experimental models relevant to ACL injuries in vitro, in situ, and in vivo. As critical hurdles to the effective and safe translation of gene therapy for clinical applications still remain, including physiological barriers and host immune responses, biomaterial-guided gene therapy inspired by drug delivery systems has been further developed to protect and improve the classical procedures of gene transfer in the future treatment of ACL injuries in patients, as critically presented here.

Knee osteoarthritis, joint laxity and PROMs following conservative management versus surgical reconstruction for ACL rupture: a meta-analysis

INTRODUCTION

Patients whose rupture of the anterior cruciate ligament (ACL) can be managed conservatively or undergo reconstruction surgery.

SOURCE OF DATA

Current scientific literature published in Web of Science, PubMed and Scopus.

AREAS OF AGREEMENT

Several studies published by July 2022 compare surgical and conservative management following ACL rupture. The latest evidence suggests that surgical management may expose patients to an increased risk of early-onset knee osteoarthritis (OA).

AREAS OF CONTROVERSY

The state of art does not recommend a systematic ACL reconstruction to all patients who tore their ACL. After the initial trauma, surgical reconstruction may produce even greater damage to the intra-articular structures compared to conservative management.

GROWING POINTS

The state of art does not recommend systematic surgical reconstruction to all patients who tore their ACL. The present study compared surgical reconstruction versus conservative management for primary ACL ruptures in terms of joint laxity, patient reported outcome measures (PROMs) and rate of osteoarthritis.

AREAS TIMELY FOR DEVELOPING RESEARCH

ACL reconstruction provides significant improvement in joint laxity compared to conservative management, but is associated with a significantly greater rate of knee osteoarthritis, despite similar results at PROM assessment.

Comparison of biomechanical analysis of four different tibial tunnel fixations in a bovine model

BACKGROUND

To determine the ideal fixation technique for an ACL reconstruction with a hamstring graft, multiple studies have been undertaken to define the initial biomechanical properties of tibial fixation.

PURPOSE

The aim of this study was to compare the biomechanical properties of tibial fixation methods by creating single or hybrid systems.

METHODS

Bovine tibias and forefoot digital extensor tendons were prepared with four different tibial anterior cruciate ligament fixation methods and compared biomechanically. Fixation materials included polyethylene Ultrabraid high-strength sutures, Biosure interference screws (Smith and Nephew, Memphis, TN, USA), staples (Smith and Nephew, Richards Regular Fixation Staples without Spikes, Memphis, TN, USA), and knotless suture anchors (Multifix-S PEEK) (Smith and Nephew, Memphis, TN, USA). Four groups (n = 5 specimens) were established - group I: single fixation with interference screws; group II: single fixation with knotless anchors; group III: hybrid fixation with interference screws and staples; group IV: hybrid fixation with interference screws and knotless anchors. Each specimen underwent evaluations for cyclic displacement, cyclic stiffness, initial loading strength, ultimate failure load, pull-out displacement, and pull-out stiffness.

RESULTS

All specimens completed cyclic loading and load-to-failure. The cyclic displacement in group II, which had a single fixation, indicated significantly greater elongation compared with the other groups (P = 0.002). The hybrid systems were more rigid than the single systems in terms of cyclic stiffness, and no statistically significant difference was observed between the hybrid systems (P = 0.461). Group IV was significantly superior in terms of the ultimate failure load (P = 0.004). No statistically significant differences were noted between the groups for pull-out displacement or pull-out stiffness.

CONCLUSION

Single fixation with bioscrews as an in-tunnel tibia fixation method was as successful as hybrid systems. Multifix-S PEEK knotless suture anchors, which can be combined with bioscrews, can be a superior fixation alternative due to its flexibility and ultimate failure load values.

Changes in Dynamic Postural Stability After ACL Reconstruction: Results Over 2 Years of Follow-up

Background:

The anterior cruciate ligament (ACL) is crucial for knee proprioception and postural stability. While ACL reconstruction (ACLR) and rehabilitation improve postural stability, the timing in improvement of dynamic postural stability after ACLR remains relatively unknown.

Purpose:

To evaluate changes in dynamic postural stability after ACLR out to 24 months postoperatively.

Study Design:

Case series; Level of evidence, 4.

Methods:

Patients undergoing ACLR were prospectively enrolled, and dynamic postural stability was assessed within 2 days before surgery, at 3-month intervals postoperatively to 18 months, then at 24 months. Measurements were made on a multidirectional platform tracking the patient’s center of mass based on pelvic motion. The amount of time the patient was able to stay on the platform was recorded, and a dynamic motion analysis score, reflecting the patient’s ability to maintain one’s center of mass, was generated overall and in 6 independent planes of motion.

Results:

A total of 44 patients with a mean age of 19.7 ± 6.2 years completed the study protocol. Overall mean dynamic postural stability improved significantly at 3, 6, 9, and 12 months after surgery, with continued improvement out to 24 months. Notable improvements occurred in medial/lateral and anterior/posterior stability from baseline to 6 months postoperatively, while internal/external rotation and flexion/extension stability declined initially after surgery from baseline to 3 months postoperatively before stabilizing to the end of the study period.

Conclusion:

Overall dynamic postural stability significantly improved up to 12 months after ACLR. Improvement in postural stability occurred primarily in the medial/lateral and anterior/posterior planes of motion, with initial decreases in the flexion/extension and internal/external rotational planes of motion.

Modular Bioreactor Design for Directed Tendon/Ligament Tissue Engineering

Functional tissue-engineered tendons and ligaments remain to be prepared in a reproducible and scalable manner. This study evaluates an acellular 3D extracellular matrix (ECM) scaffold for tendon/ligament tissue engineering and their ability to support strain-induced gene regulation associated with the tenogenesis of cultured mesenchymal stromal cells. Preliminary data demonstrate unique gene regulation patterns compared to other scaffold forms, in particular in Wnt signaling. However, the need for a robust bioreactor system that minimizes process variation was also evident. A design control process was used to design and verify the functionality of a novel bioreactor. The system accommodates 3D scaffolds with clinically-relevant sizes, is capable of long-term culture with customizable mechanical strain regimens, incorporates in-line load measurement for continuous monitoring and feedback control, and allows a variety of scaffold configurations through a unique modular grip system. All critical functional specifications were met, including verification of physiological strain levels from 1–10%, frequency levels from 0.2–0.5 Hz, and accurate load measurement up to 50 N, which can be expanded on the basis of load cell capability. The design process serves as a model for establishing statistical functionality and reliability of investigative systems. This work sets the stage for detailed analyses of ECM scaffolds to identify critical differentiation signaling responses and essential matrix composition and cell–matrix interactions.

Acute Quadriceps Tendon Rupture: Presentation, Diagnosis, and Management

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The incidence of quadriceps tendon rupture is estimated to be 1.37 cases per 100,000 people/year, with a predilection for these injuries in patients who are ≥40 years of age.

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Quadriceps tendon ruptures are more likely to occur in the presence of preexisting comorbidities such as rheumatoid arthritis, systemic lupus erythematosus, gout, chronic kidney disease, secondary hyperparathyroidism, diabetes mellitus, and peripheral vascular disease. The most common mechanism of injury is a simple fall.

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Magnetic resonance imaging is the gold-standard test for diagnosing quadriceps tendon ruptures, with a reported sensitivity, specificity, and positive predictive value of 1.0.

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Complete tears require prompt surgical intervention; the most common technique is transosseous sutures passed through longitudinal patellar drill holes. Suture anchors have been proposed as an alternative method; they have shown superior biomechanical results in cadaveric models.

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Early functional mobilization with full weight-bearing and progressive range-of-motion exercises is recommended for rehabilitation following injury.

Tibiofemoral contact and alignment in patients with anterior cruciate ligament rupture treated nonoperatively versus reconstruction : an upright, open MRI study

AIMS

Anterior cruciate ligament (ACL) rupture commonly leads to post-traumatic osteoarthritis, regardless of surgical reconstruction. This study uses standing MRI to investigate changes in contact area, contact centroid location, and tibiofemoral alignment between ACL-injured knees and healthy controls, to examine the effect of ACL reconstruction on these parameters.

METHODS

An upright, open MRI was used to directly measure tibiofemoral contact area, centroid location, and alignment in 18 individuals with unilateral ACL rupture within the last five years. Eight participants had been treated nonoperatively and ten had ACL reconstruction performed within one year of injury. All participants were high-functioning and had returned to sport or recreational activities. Healthy contralateral knees served as controls. Participants were imaged in a standing posture with knees fully extended.

RESULTS

Participants' mean age was 28.4 years (SD 7.3), the mean time since injury was 2.7 years (SD 1.6), and the mean International Knee Documentation Subjective Knee Form score was 84.4 (SD 13.5). ACL injury was associated with a 10% increase (p = 0.001) in contact area, controlling for compartment, sex, posture, age, body mass, and time since injury. ACL injury was associated with a 5.2% more posteriorly translated medial centroid (p = 0.001), equivalent to a 2.6 mm posterior translation on a representative tibia with mean posteroanterior width of 49.4 mm. Relative to the femur, the tibiae of ACL ruptured knees were 2.3 mm more anteriorly translated (p = 0.003) and 2.6° less externally rotated (p = 0.010) than healthy controls. ACL reconstruction was not associated with an improvement in any measure.

CONCLUSION

ACL rupture was associated with an increased contact area, posteriorly translated medial centroid, anterior tibial translation, and reduced tibial external rotation in full extension. These changes were present 2.7 years post-injury regardless of ACL reconstruction status. Cite this article: Bone Joint J 2021;103-B(9):1505-1513.

Return to competition after anterior cruciate ligament injuries in world class judoka

OBJECTIVES

The purpose of this study was to quantify how the return to competition after an anterior cruciate ligament rupture in Judo is perceived by athletes as compared to doctors and physiotherapists. Is there a difference between the perspectives of doctors and physiotherapists and athletes regarding surgery, time loss due to injury, or the level of performance after the injury? Which functional tests are used to define when or if athletes are ready for the return to competition?

METHODS

A survey-based retrospective study design with two surveys regarding the treatment methods of an anterior cruciate ligament rupture was established: one version for athletes and one for doctors and physiotherapists. Surveys were equivalent for both populations despite the athletes' individual data. Variance analysis was applied to assess if statistically meaningful differences exist between the two groups.

RESULTS

From 232 judoka interviewed during the Junior World Judo Championships 2017, 23 suffered an anterior cruciate ligament rupture in the last 2 years. As high as 52% underwent surgery. According to doctors and physiotherapists, 82% of athletes underwent reconstructive surgeries. Athletes returned to competition after 5.5 months, whereas doctors and physiotherapists assumed a time loss of 8.4 months. Only 44% of the doctors and physiotherapists used functional tests like hop tests for defining return to competition and 22% used mental tests. When asking athletes, the use of hop tests (8%) and mental tests (0%) was even lower.

CONCLUSION

The study demonstrated for the first time significant discrepancies between the medical treatment regarding the recommendations of doctors and physiotherapists compared to athletes behavior. To support a conclusive statement, we should encourage the doctors and physiotherapists to use functional test batteries for the decision-making process regarding return to competition.

Occurrence of inadequate ACL healing after Dynamic Intraligamentary Stabilization and functional outcome-a multicentre case series

Introduction

Dynamic Intraligamentary Stabilization (DIS) is a technique for preservation, anatomical repair and stabilization of a freshly injured anterior cruciate ligament (ACL). The main purpose of this study was to evaluate the short-term re-operation rate when compared to traditional autograft reconstruction.

Methods

Four, from the developer independent, centres enrolled patients that underwent ACL repair by DIS, according to the specific indications given by MRI imaging at a minimum follow-up of 12 months. The re-operation rate was recorded as primary outcome. Secondary outcome measures were the postoperative antero-posterior knee laxity (using a portable Rolimeter®), as well as the Tegner, Lysholm and IKDC Scores.

Results

A total of 105 patients were investigated with a median follow-up of 21 months. Thirteen patients were lost to follow-up. Of the remaining 92 patients 15 (16.3%) had insufficient functional stability and required subsequent ACL reconstruction. These patients were excluded from further analysis, leaving 77 consecutive patients for a 12 months follow-up. The median age at time of surgery was 30 years for that group. At time of follow-up a median antero-posterior translation difference of 2 mm was measured. None of these patients reported subjective insufficiency (giving way), but in 14 patients (18.2%), the difference of antero-posterior translation was more than 3 mm. We found a median Tegner Score of 5.5, a median Lysholm Score of 95.0 and a median IKDC Score of 89.4.

Conclusion

The main finding of this multicentre study is a relevant re-operation rate of 16.3%. Another 18.2% showed objective antero-posterior laxity (≥ 3 mm) during testing raising the suspicion of postoperative non-healing. The failure rate of DIS in this study is higher than for reconstruction with an autologous tendon graft. However, our successfully treated patients had a good clinical and functional outcome based on antero-posterior knee laxity and clinical scores, comparable to patients treated by autograft reconstruction.

Can a Knee Brace Prevent ACL Reinjury: A Systematic Review

This systematic review aimed to investigate whether the use of a knee brace when returning to sport (RTS) could prevent a second injury after anterior cruciate ligament reconstruction (ACLR). This study was registered with the PROSPERO database and followed PRISMA guidelines. A systematic search of PubMed, Ovid Medline, Ovid All EBM Reviews, Ovid Embase, EBSCO Sportdiscus and ISI Web of Science databases for meta-analysis, randomized controlled trials and prospective cohort studies published before July 2020 was undertaken. The inclusion criteria were: (1) Comparing with and without a brace at RTS, (2) follow up of at least 18 months after ACLR, (3) reinjury rates included in the outcomes. Two reviewers independently extracted the data. Quality appraisal analyses were performed for each study using the Cochrane Collaboration tools for randomized and nonrandomized trials. A total of 1196 patients in three studies were included. One study showed a lower rate of reinjury when wearing a knee brace at RTS. One study found the knee brace to have a significant protective effect for younger patients (≤17 years). The effectiveness of knee bracing when RTS remains ambiguous. Current data cannot support that using a knee brace when RTS will decrease the rate of reinjury after ACL reconstruction.

Computed Tomography Imaging of BioComposite Interference Screw After ACL Reconstruction With Bone-Patellar Tendon-Bone Graft

Background:

Bioabsorbable interference screws tend to have high resorption rates after anterior cruciate ligament (ACL) reconstruction; however, no studies have examined screws composed of 30% biphasic calcium phosphate and 70% poly-d-lactide (30% BCP/70% PLDLA).

Purpose:

To evaluate femoral and tibial tunnel widening and resorption of 30% BCP/70% PLDLA interference screws and replacement with bone at 2 to 5 years after ACL reconstruction using bone–patellar tendon–bone (BTB) autograft.

Study Design:

Case series; Level of evidence, 4.

Methods:

Included were 20 patients who had undergone ACL reconstruction using BTB autograft and were reevaluated 2 to 5 years after surgery using computed tomography scans. Tunnel measurements were obtained from computed tomography scans in the sagittal and coronal planes and were compared with known tunnel measurements based on operative reports. These images and measurements were used to assess tunnel widening, resorption of the 30% BCP/70% PLDLA screw, its replacement with bone, and possible cyst formation. Paired t tests were used to compare initial and final femoral and tibial tunnel measurements.

Results:

The cross-sectional area of the femoral tunnel decreased at the aperture (P = .03), middle (P = .0002), and exit (P < .0001) of the tunnel compared with the initial femoral tunnel size, and the tibial tunnel cross-sectional area decreased at the aperture (P < .0001) and exit (P = .01) of the tunnel compared with the initial tibial tunnel size. Bone formation was observed in 100% of femoral tunnels and 94.7% of tibial tunnels. Screw resorption was 100% in the femur and 94.7% in the tibia at the final follow-up. Cysts were noted around the femoral tunnel in 2 patients (5.1%).

Conclusion:

The 30% BCP/70% PLDLA interference screws used for ACL reconstruction using BTB autograft had high rates of resorption and replacement with bone, and there were no increases in tunnel size at 2 to 5 years postoperatively. The authors observed a low rate of cyst formation and no other adverse events stemming from the use of this specific biointerference screw, suggesting that this type of screw is a reasonable option for graft fixation with minimal unfavorable events and a reliable resorption profile.

Reconstruction of the cranial cruciate ligament using a semitendinosus autograft in a lapine model

OBJECTIVE

To clarify and improve a cranial cruciate ligament (CrCL) deficient stifle stabilization technique using a semitendinosus tendon (ST) autograft fixed with an interference fit screw (IFS) in a closed-joint trauma lapine osteoarthritis (OA) model.

STUDY DESIGN

Experimental OA model.

ANIMALS

Forty-one Flemish Giant rabbits.

METHODS

Following arthrotomy of traumatized lapine stifles, the ST insertion on the tibial plateau was exposed and the ST was transected near its origin. The graft was passed through tibial and femoral tunnels, manually tensioned and then secured in place with a custom IFS and periosteal sutures. Drawer was manually assessed during and immediately after surgery intraoperatively. Upon euthanasia, joint laxity was measured at 2, 10, or 22 weeks postoperatively and compared to that of the contralateral, intact stifles and stifles with a surgically transected CrCL.

RESULTS

Minimal postoperative drawer was present in 34% of the rabbits and potentially correlated with meniscal injury and subsequent meniscectomy. CrCL reconstruction significantly reduced joint laxity to a level (3.6 ± 1.6 mm) similar to that (2.7 ± 0.8 mm) in contralateral intact stifles.

CONCLUSION

Surgical replacement of a traumatically injured CrCL using a ST autograft fixed with an IFS replicated a common human surgical technique and effectively restored joint stability in the short, medium, and long terms of the study.

CLINICAL SIGNIFICANCE

The study provides researchers a useful, clinically relevant, post-traumatic CrCL deficient rabbit model for the study of OA and investigations of interventions to mitigate or prevent long-term joint degeneration.

The influence of decision making and divided attention on lower limb biomechanics associated with anterior cruciate ligament injury: a narrative review

Cognitive loads have been shown to influence anterior cruciate ligament (ACL) injury risk. Two main sources of cognitive loads that athletes experience are decision making and dividing attention between multiple tasks. The aim of this paper was to review previous studies examining the effects of decision making and divided attention on lower limb biomechanics during landing and cutting. Previous research has shown decision making to significantly influence a number of biomechanical variables associated with increased risk of ACL injury, such as reduced knee flexion at initial contact, increased knee valgus angles, increased knee extension moment and increased knee valgus moment in decision-making tasks compared to pre-planned tasks. Furthermore, dividing attention between multiple tasks has been shown to result in reduced knee flexion at initial contact, increased vertical ground reaction force, and reduced stability during landing/cutting. The changes in lower limb biomechanics observed as a result of both decision making and dividing attention are likely due to a reduced ability to anticipate ground contact and implement protective movement patterns associated with reduced ACL loading. Collectively, these findings emphasise the need for tasks that incorporate decision making and divided attention when investigating ACL injury mechanisms and developing ACL injury risk screening assessments.

Tranexamic Acid Use in Knee and Shoulder Arthroscopy Leads to Improved Outcomes and Fewer Hemarthrosis-Related Complications: A Systematic Review of Level I and II Studies

PURPOSE

To systematically review the literature to compare the efficacy and safety of tranexamic acid (TXA) as a means to minimize hemarthrosis-related complications after arthroscopic procedures of the knee, hip, and shoulder.

METHODS

A systematic review according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed by searching PubMed, Cochrane Library, and Embase databases to locate randomized controlled trials comparing the clinical outcomes and postoperative complications of patients undergoing arthroscopy with and without TXA. Search terms used were "tranexamic acid," "arthroscopy," "knee," "hip," and "shoulder." Patients were evaluated based on early (<6 weeks) postoperative signs of hemarthrosis using the Coupens and Yates classification, postoperative complications (myocardial infarction, stroke, venous thromboembolism events), range of motion (ROM), and patient-reported outcome scores (Visual analog scale, Subjective International Knee Documentation Committee, Lysholm, and Tegner activity scores).

RESULTS

Five studies (2 level I and 3 level II) met inclusion criteria, including a total of 299 patients undergoing arthroscopy with TXA and 299 patients without TXA. The average follow-up duration for all patients was 43.9 days. Procedures performed were partial meniscectomy, anterior cruciate ligament reconstruction, and rotator cuff repair. No studies evaluating TXA use in hip arthroscopy were identified. Coupens-Yates hemarthrosis grades significantly improved in the TXA groups across all studies. Three studies found TXA patients to experience significantly less postoperative pain at latest follow-up, 1 study found TXA patients to have significantly better postoperative Lysholm scores, and 1 study found TXA patients to have significantly more ROM at latest follow-up compared with non-TXA patients (P < .05).

CONCLUSION

Patients undergoing arthroscopy, particularly arthroscopic meniscectomy, arthroscopic-assisted anterior cruciate ligament reconstruction, and arthroscopic rotator cuff repair, with TXA can be expected to experience improved outcomes and less hemarthrosis-related complications in the early postoperative period compared with non-TXA patients.

LEVEL OF EVIDENCE

II, systematic review of level I and II studies.

Comparison of the Position-Matching and Position-Reproducing Tasks to Detect Deficits in Knee Position Sense After Reconstruction of the Anterior Cruciate Ligament

CONTEXT

Deficits in knee position sense following reconstruction of the anterior cruciate ligament (ACL) can delay an athlete's return to sport participation and increase the risk of reinjury. Deficits in position sense postreconstruction have been evaluated using either a position-reproducing or position-matching task.

OBJECTIVE

The aim of our study was to combine both to determine which assessment would be more effective to identify deficits in knee position sense.

DESIGN

Longitudinal laboratory-based study.

PARTICIPANTS

Eleven athletes (6 men and 5 women; mean age, 20.5 [1.2] y), who had undergone ACL reconstruction with an ipsilateral hamstring autograft, and 12 age-matched controls.

INTERVENTIONS

Position sense was evaluated at 6 and 12 months postreconstruction and once for the control group. In addition, peak isokinetic knee extension and flexion strength, at 60°/s and 180°/s, was assessed for the ACL reconstruction group to evaluate possible influences of muscle strength on knee joint position sense.

MAIN OUTCOME MEASURES

The variables include the angular differences between the reference limb and indicator limb, and peak torque values of isokinetic knee extension and flexion.

RESULTS

Significant matching differences were identified at 6 months postsurgery on the position-matching task, but not at 12 months postsurgery. No significant between-group and within-subject differences were identified on the position-reproducing task. No significant matching errors were identified for the control group. There was no correlation between errors in position sense and maximum isokinetic strength.

CONCLUSION

The position-matching task is more sensitive than the position-reproducing task to identify deficits in knee position sense over the first year following ACL reconstruction surgery.

Joint movement variability during landing in patients with anterior cruciate ligament reconstruction

BACKGROUND

Rapid knee valgus and knee internal rotation motions in the initial phase of landing are the known mechanisms for anterior cruciate ligament injury, and many studies have been investigated on knee joint peak angle during landing. However, the variability in joint movement during landing has not been fully investigated. This study aimed to compare the coefficient of variation of lower extremity range of motion in patients with anterior cruciate ligament reconstruction and healthy subjects during landing.

METHODS

In this cross-sectional study, 54 patients with anterior cruciate ligament reconstruction and 44 healthy subjects were enrolled. All participants underwent six trials of single-leg hop landing for maximum safe horizontal distance. The kinematic variables were the coefficient of variation during two discrete (0.05 after initial contact and maximum knee flexion) time points for selected three-dimensional hip and knee joint range of motion. Comparisons were performed between the two groups.

RESULTS

Compared with healthy subjects, patients with anterior cruciate ligament reconstruction had greater the coefficient of variation in hip internal/external rotation range of motion (patients with anterior cruciate ligament reconstruction had 41.9%, healthy subjects had 25.5%; P=0.0018; effect size: 0.32) and knee internal/external rotation range of motion (patients with anterior cruciate ligament reconstruction had 68.4%; healthy subjects had 48.1%; P=0.0014; effect size: 0.32) for periods that spanned 0.05 s from the initial contact.

CONCLUSIONS

Patients with anterior cruciate ligament reconstruction could be disadvantageous in ability to control and adapt hip and knee joint rotations when controlling landings.

A Cell-free Biodegradable Synthetic Artificial Ligament for the Reconstruction of Anterior Cruciate Ligament in a Rat Model

Traditional Anterior Cruciate Ligament (ACL) reconstruction is commonly performed using an allograft or autograft and possesses limitations such as donor site morbidity, decreased range of motion, and potential infection. However, a biodegradable synthetic graft could greatly assist in the prevention of such restrictions after ACL reconstruction. In this study, artificial grafts were generated using "wet" and "dry" electrospinning processes with a biodegradable elastomer, poly (ester urethane) urea (PEUU), and were evaluated in vitro and in vivo in a rat model. Four groups were established: (1) Wet PEUU artificial ligament, (2) Dry PEUU artificial ligament, (3) Dry polycaprolactone artificial ligament (PCL), and (4) autologous flexor digitorum longus tendon graft. Eight weeks after surgery, the in vivo tensile strength of wet PEUU ligaments had significantly increased compared to the other synthetic ligaments. These results aligned with increased infiltration of host cells and decreased inflammation within the wet PEUU grafts. In contrast, very little cellular infiltration was observed in PCL and dry PEUU grafts. Micro-computed tomography analysis performed at 4 and 8 weeks postoperatively revealed significantly smaller bone tunnels in the tendon autograft and wet PEUU groups. The Wet PEUU grafts served as an adequate functioning material and allowed for the creation of tissues that closely resembled the ACL.

Anterior Knee Pain After Anterior Cruciate Ligament Reconstruction

Background

Anterior knee pain is a frequent condition after anterior cruciate ligament reconstruction (ACLR), but its origin remains uncertain. Studies have suggested that donor site morbidity in autologous bone-patellar tendon-bone reconstructions may contribute to patellofemoral pain, but this does not explain why hamstring tendon reconstructions may also present with anterior pain.

Purpose

To evaluate the prevalence of anterior knee pain after ACLR and its predisposing factors.

Study Design

Case-control study; Level of evidence, 3.

Methods

We evaluated the records of all patients who underwent ACLR between 2000 and 2016 at a private facility. The prevalence of anterior knee pain after surgery was assessed, and possible risk factors (graft type, patient sex, surgical technique, range of motion) were evaluated.

Results

The records of 438 patients (mean age, 30 years) who underwent ACLR were analyzed. Anterior knee pain was found in 6.2% of the patients. We found an increased prevalence of anterior knee pain with patellar tendon graft, with an odds ratio of 3.4 (P = .011). Patients who experienced extension deficit in the postoperative period had an odds ratio of 5.3 of having anterior pain (P < .001). Anterior knee pain was not correlated with patient sex or surgical technique.

Conclusion

The chance of having anterior knee pain after ACLR was higher when patellar tendon autograft was used compared with hamstring tendon graft, as well as in patients who experienced extension deficit in the postoperative period.

Epidemiological Trends of Anterior Cruciate Ligament Reconstruction in a Canadian Province

OBJECTIVE

To determine epidemiological trends of anterior cruciate ligament reconstruction (ACL-R) in a Canadian province, estimate the national incidence, and compare with internationally published data.

DESIGN

Retrospective review.

SETTING

All hospitals that performed ACL reconstructions in Manitoba between 1980 and 2015.

PARTICIPANT

All patients that underwent ACL-R in Manitoba between 1980 and 2015.

INTERVENTION

This is a retrospective review looking at deidentified, individual-level administrative records of health services used for the entire population of Manitoba (approximately 1.3 million). Codes for ACL and cruciate ligament reconstruction were searched from 1980 to 2015. Patient demographics included age, sex, geographic area of residence, and neighborhood income quintile.

MAIN OUTCOME MEASURES

Trends of ACL reconstructions from 1980 to 2015.

RESULTS

A total of 10 114 ACL-R were performed during the 36-year study period and patients were predominantly male (63.1%). The mean age at ACL-R was 29.5 years (SD 10.0) for males and 28.5 years (SD 11.9) for females, whereas age younger than 40 years accounted for 81.7% of all ACL-R. The incidence of ACL-R increased from 7.56/100 000 inhabitants in 1980 to 48.45/100 000 in 2015. The proportion of females undergoing ACL-R has increased from 29.3% in 1980% to 41.9% in 2015, and female patients now comprise the majority of ACL-R in the under-20 age category.

CONCLUSION

The incidence of ACL-R has significantly increased since 1980; female patients now make up a greater proportion than males of the ACL-R population younger than 20 years. This information can be used to guide resource allocation planning and focus injury prevention initiatives.

Implementation of Endogenous and Exogenous Mesenchymal Progenitor Cells for Skeletal Tissue Regeneration and Repair

Harnessing adult mesenchymal stem/progenitor cells to stimulate skeletal tissue repair is a strategy that is being actively investigated. While scientists continue to develop creative and thoughtful ways to utilize these cells for tissue repair, the vast majority of these methodologies can ultimately be categorized into two main approaches: (1) Facilitating the recruitment of endogenous host cells to the injury site; and (2) physically administering into the injury site cells themselves, exogenously, either by autologous or allogeneic implantation. The aim of this paper is to comprehensively review recent key literature on the use of these two approaches in stimulating healing and repair of different skeletal tissues. As expected, each of the two strategies have their own advantages and limitations (which we describe), especially when considering the diverse microenvironments of different skeletal tissues like bone, tendon/ligament, and cartilage/fibrocartilage. This paper also discusses stem/progenitor cells commonly used for repairing different skeletal tissues, and it lists ongoing clinical trials that have risen from the implementation of these cells and strategies. Lastly, we discuss our own thoughts on where the field is headed in the near future.

Contralateral Anterior Cruciate Ligament Injuries Following Index Reconstruction in the Pediatric Athlete

PURPOSE OF REVIEW

The purpose of this review is to discuss relevant anatomy and pathoanatomy in the knee following anterior cruciate ligament reconstruction, risk factors for contralateral ACL tear, and mechanisms of contralateral injuries in the pediatric population.

RECENT FINDINGS

Contralateral ACL rupture rates following ACL reconstruction (ACLR) range from 4% to 42%. Pediatric patients show increased risk compared with adults, likely due to inherent anatomical differences along with biomechanical and neuromuscular changes that occur in both the operative and contralateral knees following index ACLR. Pediatric athletes who return to sport more quickly have been found to be at increased risk for contralateral tears, as have athletes who participate in cutting and pivoting sports. Contralateral tears tend to occur via non-contact mechanisms. Pediatric patients are at increased risk of contralateral ACL injury following index ACL reconstruction compared with adults. Further study is warranted to determine appropriate biologic, functional, and rehabilitative parameters gauged toward preventing contralateral ACL tear while minimizing time lost from sport.

Artificial ligament made from silk protein/Laponite hybrid fibers

With developments in tissue engineering, artificial ligaments are expected to be future materials for anterior cruciate ligament (ACL) reconstruction. However, poor healing of the intraosseous part after ACL reconstruction significantly hinders their applications in this field. In this study, a bioactive clay Laponite (LAP) was introduced into the regenerated silk fibroin (RSF) spinning dope to produce functional RSF/LAP hybrid fibers by wet-spinning. These RSF/LAP hybrid fibers were then woven into artificial ligament for ACL reconstruction. The structure and mechanical properties of RSF/LAP hybrid fibers were extensively studied by different means. Results confirmed the presence of LAP in RSF fibers and revealed that the addition of LAP slightly deteriorated the comprehensive mechanical properties of RSF fibers. However, they were still much tougher (with higher breaking energy) than those of degummed natural silkworm silk that was earlier used for making artificial ligament. The artificial ligament woven from RSF/LAP hybrid fibers showed better cytocompatibility and osteogenic differentiation with mouse pre-osteoblasts in vitro than those made from degummed natural silkworm silks and pure RSF fibers. Furthermore, in vivo study in a rat ACL reconstruction model demonstrated that the presence of LAP in the artificial ligament could significantly enhance the graft osseointegration process and also improve the corresponding biomechanical properties of the artificial ligament. Based upon these results, the RSF/LAP hybrid fibers, which can be mass produced by wet-spinning process, are believed to have a great potential for use as artificial ligament materials for ACL reconstruction. STATEMENT OF SIGNIFICANCE: In this study, we successfully introduced Laponite (LAP), a kind of clay that has the function of osteogenic induction, into regenerated silk fibroin (RSF) fibers, which was prepared by a mature wet-spinning method developed in our lab. We believe that through artificial spinning, additional functional components can be added into RSF fibers, which one can hardly achieve with natural silks. We showed that the artificial ligament woven from RSF/LAP hybrid fibers had better cytocompatibility and osteogenic differentiation for mouse pre-osteoblasts in vitro, and significantly enhanced the graft osseointegration process and improved the corresponding biomechanical properties in a rat ACL reconstruction model in vivo, compared to those artificial ligaments made from degummed natural silkworm silks and pure RSF fibers.

Effect of Teaching Session on Resident Ability to Identify Anatomic Landmarks and Anterior Cruciate Ligament Footprint: A Study Using 3-Dimensional Modeling

Background:

Femoral tunnel positioning in anterior cruciate ligament reconstruction (ACLR) is an intricate procedure that requires highly specific surgical skills.

Purpose:

To report the ability of residents to identify femoral landmarks and the native ACL footprint before and after a structured formal teaching session as a reflection of overall surgical skill training for orthopaedic surgery residents in Canada.

Study Design:

Controlled laboratory study.

Methods:

A total of 13 senior orthopaedic residents were asked to identify a femoral landmark and an ACL footprint on ten 3-dimensional (3D)–printed knee models before and after a teaching session during the fall of 2018. The 3D models were made based on actual patients with different anatomic morphologic features. ImageJ software was used to quantify the measurements, which were then analyzed through use of descriptive statistics.

Results:

Before and after the teaching session, residents attempted to identify a specific anatomic location (bifurcate and intercondylar ridge intersection) with a mean error per participant ranging from 5.00 to 10.95 mm and 4.79 to 12.13 mm in magnitude, respectively. Furthermore, before and after the teaching session, residents identified the specific position to perform the surgical procedure (ACL femoral footprint), with a mean error per participant ranging from 4.58 to 8.80 mm and 3.87 to 11.07 mm in magnitude, respectively. The teaching session resulted in no significant improvement in identification of either the intersection of the bifurcate and intercondylar ridges (P = .9343 in the proximal-distal axis and P = .8133 in the anteroposterior axis) or the center of the femoral footprint (P = .7761 in the proximal-distal axis and P = .9742 in the anteroposterior axis).

Conclusion:

Although a formal teaching session was combined with a hands-on session that entailed real surgical instrumentation and fresh cadaveric specimens, the intervention seemed to have no direct impact on senior residents’ performance or their ability to demonstrate the material taught. This puts into question the format and efficacy of present teaching methods. Also, it is possible that the 3D spatial perception required to perform these skills is not something that can be taught effectively through a teaching session or at all. Further investigation is required regarding the effectiveness and application of surgical skill laboratories and simulations on the competencies of orthopaedic residents.

Does the Application of Platelet-Rich Fibrin in Anterior Cruciate Ligament Reconstruction Enhance Graft Healing and Maturation? A Comparative MRI Study of 44 Cases

Background:

Anterior cruciate ligament (ACL) reconstruction performed with growth factors and activated platelets has been suggested to accelerate tendon ligamentization, leading to earlier return to daily activities and sports.

Hypotheses:

Platelet-rich fibrin (PRF) will result in improved graft maturation and healing as evaluated by magnetic resonance imaging (MRI) in patients undergoing hamstring ACL reconstruction. Hemostatic and analgesic properties of PRF will lead to less postoperative blood loss and pain.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A total of 44 patients with isolated ACL injuries who underwent arthroscopic all-inside anatomic single-bundle ACL reconstruction with semitendinosus tendon graft were enrolled. Group 1 included 23 patients who had PRF sprayed to the surface of the graft; group 2 included 21 patients for whom no PRF was used. Patients were discharged after 24 hours and examined for hemarthrosis that needed to be aspirated. MRI was performed at the fifth postoperative month. A blinded radiologist evaluated graft maturation according to its signal intensity and the presence of synovial fluid at the tunnel-graft interface.

Results:

PRF-treated grafts demonstrated lower MRI signal intensity and less fluid in the graft-tunnel interface as compared with controls for the entire length of the graft. The mean full-length MRI signal intensities were 9.19 versus 16.59 (P = .047) for groups 1 and 2, respectively. Subgroup analysis of the semitendinosus grafts demonstrated a signal intensity of 11.57 versus 23.98 (P = .044) for the proximal third, 9.53 versus 13.83 (P = .237) for the midbody, and 6.48 versus 11.98 (P = .087) for the distal third. Synovial fluid at the graft-tunnel interface was detected in 1 patient in group 1 (4.3%) and 3 patients in group 2 (14.3%; P < .001). Patients in group 1 had significantly less hemarthrosis that needed to be aspirated (P = .003), while postoperative analgesia requirements were similar in both groups (P = .08). No clinical benefit of PRF could be demonstrated in clinical outcomes.

Conclusion:

Application of PRF led to superior graft integration and maturation in the proximal third of the ACL graft. There was no significant difference in MRI signal intensity in the midbody or distal tibial graft. Application of PRF also resulted in significantly lower rates of postoperative hemarthrosis that needed to be aspirated.

Thermosensitive Chitosan-Gelatin-Glycerol Phosphate Hydrogels as Collagenase Carrier for Tendon-Bone Healing in a Rabbit Model

Healing of an anterior cruciate ligament graft in bone tunnel yields weaker fibrous scar tissue, which may prolong an already prolonged healing process within the tendon-bone interface. In this study, gelatin molecules were added to thermosensitive chitosan/β-glycerol phosphate disodium salt hydrogels to form chitosan/gelatin/β-glycerol phosphate (C/G/GP) hydrogels, which were applied to 0.1 mg/mL collagenase carrier in the tendon-bone junction. New Zealand white rabbit's long digital extensor tendon was detached and translated into a 2.5-mm diameter tibial plateau tunnel. Thirty-six rabbits underwent bilateral surgery and hydrogel injection treatment with and without collagenase. Histological analyses revealed early healing and more bone formation at the tendon-bone interface after collagenase partial digestion. The area of metachromasia significantly increased in both 4-week and 8-week groups after collagenase treatment (p < 0.01). Micro computed tomography showed a significant increase in total bone volume and bone volume/tissue volume in the 8 weeks after collagenase treatment, compared with the control group. Load-to-failure was significantly higher in the treated group at 8 weeks (23.8 ± 8.13 N vs 14.3 ± 3.9 N; p = 0.008). Treatment with collagenase digestion resulted in a 66% increase in pull-out strength. In conclusion, injection of C/G/GP hydrogel with collagenase improves tendon-to-bone healing in a rabbit model.

Influence of operative technique on anterior cruciate ligament reconstruction in patients older than 50 years

BACKGROUND

A consequence of the steady growth in the worldwide population of elderly individuals who remain in good health and continue to engage in sports is an increase in the incidence of anterior cruciate ligament (ACL) rupture occurring after 50 years of age. ACL reconstruction was formerly reserved for young athletes but now seems to produce good outcomes in over 50s. The type of graft and graft fixation method were selected empirically until now, given the absence of investigations into potential relationships of these two parameters with the outcomes. The objective of this study was to assess associations linking the type of graft and the method of femoral graft fixation to outcomes in patients older than 50 years at ACL reconstruction.

HYPOTHESIS

The operative technique is not associated with the clinical outcomes or differential laxity.

MATERIAL AND METHODS

A multicentre retrospective cohort of 398 patients operated between 1 January 2011 and 31 December 2015 and a multicentre prospective cohort of 228 patients operated between 1 January 2016 and 30 June 2017 were conducted. Mean follow-up was 42.7 months in the retrospective cohort and 14.2 months in the prospective cohort. The primary evaluation criterion was the clinical outcome as assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Tegner Activity Score (TAS). Differential laxity was the secondary evaluation criterion. The Wilcoxon rank sum test and Kruskal-Wallis test were used to compare groups, and p-values<0.05 were considered significant.

RESULTS

In the retrospective and prospective cohorts, hamstring tendons were used in 269 (67.6%) and 197 (86.4%) patients and extensor apparatus tendons in 124 (31.2%) and 31 (13.6%) patients. Femoral fixation in the retrospective cohort was cortical in 81 (20.4%) cases, by press-fit in 112 (28.1%) cases, and by interference screw in 205 (51.5%) cases; corresponding figures in the prospective cohort were 135 (59.2%), 17 (7.5%), and 76 (33.3%). The multivariate analysis of the retrospective data identified no significant associations of graft type or femoral fixation type with the KOOS, TAS, or differential laxity values. In the prospective cohort, hamstring grafts were associated with 0.6mm of additional laxity (p=0.007); compared to cortical fixation, press-fit fixation of patellar tendon grafts was associated with 0.3mm of additional laxity (p=0.029) and a 0.5-point lower TAS value (p=0.033), with no difference in KOOS values. None of these differences were clinically significant.

DISCUSSION

The various ACL reconstruction techniques used in patients older than 50 years produce similar outcomes. The technique can be chosen based on surgeon preference without regard for patient age.

LEVEL OF EVIDENCE

IV.

Outcomes Following ACL Reconstruction Based on Graft Type: Are all Grafts Equivalent?

PURPOSE OF REVIEW

Anterior cruciate ligament reconstruction is one of the most common orthopedic procedures performed, accounting for over 200,000 cases annually. Despite the high prevalence, there is still much debate as to the optimal graft choice. The purpose of this review is to evaluate the current literature and discuss the reported outcomes for the most common graft choices.

RECENT FINDINGS

The most common autografts being used include bone-patellar tendon-bone (BPTB), hamstring tendon (HT), and quadriceps tendon (QT). Hamstring tendon might have a slightly higher re-tear rate when compared with BPTB (2.84 versus 2.80). However, BPTB has a higher rate of anterior knee and kneeling pain in the short- and mid-term follow-up. This has not been shown to be the case in long-term follow-up. Allograft is a viable option for revisions and primaries in patients greater than 35 years old; however, re-tear rate increases significantly in younger patients. ACL reconstruction graft choice is a highly studied and yet still exceedingly debated topic. Most large studies report either no significant difference or a small difference in failure rate and outcome scores between the different autograft choices. Allografts have been demonstrated to have an increased risk of failure in younger athletes and should be reserved for revision cases and those aged 35 years and older. Graft choice should ultimately be decided upon based on surgeon comfort and experience and individual patient characteristics.

Peroneus longus autograft can be recommended as a superior graft to hamstring tendon in single-bundle ACL reconstruction

PURPOSE

A peroneus longus tendon autograft is used in many orthopaedic procedures and it is biomechanically comparable to a hamstring tendon autograft. Despite its potential, there are few studies that have evaluated the use of the peroneus longus tendon in ACL reconstruction. The aim of this study was to compare the clinical outcome and donor site morbidity of ACL reconstruction with hamstring tendon autografts versus peroneus longus tendon autografts in patients with an isolated ACL injury.

METHODS

Patients who underwent isolated single-bundle ACL reconstruction were allocated to two groups (hamstring and peroneus longus) and observed prospectively. Graft diameter was measured intraoperatively. Functional scores (IKDC, modified Cincinnati and Lysholm scores) were recorded preoperatively and 1 year after surgery. Donor site morbidities were assessed with thigh circumference measurements and ankle scoring with the AOFAS and FADI.

RESULTS

Fifty-two patients (hamstring n = 28, peroneus n = 24) met the inclusion criteria. The peroneus longus graft diameter (8.8 ± 0.7 mm) was significantly larger than the hamstring diameter (8.2 ± 0.8 mm) (p = 0.012). There were no significant differences between the pre- and 1-year postoperative score between the hamstring and peroneus longus groups in the IKDC (n.s), modified Cincinnati (n.s), and Lysholm (n.s). The mean for the AOFAS was 97.3 ± 4.2 and for the FADI 98 ± 3.4 in the peroneus longus group, with a significant decrease in thigh circumference in the hamstring group (p = 0.002).

CONCLUSION

Anterior cruciate ligament reconstruction with peroneus longus autografts produces a functional score (IKDC, modified Cincinnati, Lysholm) comparable to that of hamstring autografts at a 1-year follow-up, with the advantages of larger graft diameter, less thigh hypotrophy and excellent ankle function based on AOFAS and FADI scores.

LEVEL OF EVIDENCE

Prospective cohort study, Level II.

Age over 50 years is not a contraindication for anterior cruciate ligament reconstruction

PURPOSE

To report clinical and functional results of ACL reconstruction in patients over 50 years old and investigate the influence of surgery on osteoarthritis progression in this cohort of patients.

METHODS

A systematic review was performed on PubMed, Scopus, Google scholar, Cochrane library and EMBASE, using a strategy search design to collect clinical studies reporting outcomes of ACL reconstruction in patients aged 50 years or older. The primary outcome measure was clinical and functional results, including failure rate defined as reoperation for revision ACL surgery or conversion to total knee arthroplasty; secondary outcomes included radiological findings, expressed according to the validated grading score.

RESULTS

A total of 16 studies were found suitable and included. Overall, 470 arthroscopic ACL reconstructions were performed in 468 patients (278 males, 190 females), with a mean age of 53.6 years (50-75 years). The total failure rate, described as reoperation for revision ACL surgery was 2.7% (10 knees), ranging from 0 to 14.3% in the selected studies. All papers reviewed showed a statistically significant improvement of clinical and functional scores at final follow-up, comparable to younger control group, when reported. Post-operative objective stability testing with KT-1000 arthrometer device or equivalent was performed in seven studies, with a mean side-to-side difference of 2.2 mm (0.2-2.7 mm). Radiographic signs of progression of osteoarthritis were reported in six studies, where severe signs of degeneration (grade 3 or 4 according Kellgren-Lawrence or Ahlbäck classification) shifted from 4 out of 216 knees (1.9%) before surgery to 28 out of 187 knees (15%) following ACL reconstruction, after a mean period of follow-up ranging from 32 to 64 months.

CONCLUSION

ACL reconstruction in patients older than 50 years is a safe procedure with good results that are comparable to those of younger patients previously reported. Age itself is not a contraindication to ACL surgery because physiological age, clinical symptoms and functional requests are more important than chronological age in decision process. Since cohort size in the present study is not large enough, and taking into account the high occurrence of concomitant meniscal and chondral lesions, more high-quality studies are necessary to draw definitive conclusions about development of osteoarthritis of the knee after ACL surgery in these patients.

LEVEL OF EVIDENCE

IV.

Knitted Silk-Collagen Scaffold Incorporated with Ligament Stem/Progenitor Cells Sheet for Anterior Cruciate Ligament Reconstruction and Osteoarthritis Prevention

Current surgical management of anterior cruciate ligament (ACL) rupture still remains an intractable challenge in ACL regeneration due to the weak self-healing capability of ACL. Inadequate cell numbers and vascularization within the articular cavity contribute mainly to the poor prognosis. This time, we fabricated a new tissue engineering scaffold by adding ligament stem/progenitor cell (LSPC) sheets to our previous knitted silk-collagen sponge scaffold, which overcame these limitations by providing sufficient numbers of seed cells and a natural extracellular matrix to facilitate regeneration. LSPCs display excellent proliferation and multilineage differentiation capacity. Upon ectopic implantation, the knitted silk-collagen sponge scaffold incorporated with an LSPC sheet exhibited less immune cells but more fibroblast-like cells, deposited ECM and neovascularization, and better tissue ingrowth. In a rabbit model, we excised the ACL and performed a reconstructive surgery with our scaffold. Increased expression of ligament-specific genes and better collagen fibril formation could be observed after orthotopic transplantation. After 6 months, the LSPC sheet group showed better results on ligament regeneration and ligament-bone healing. Furthermore, no obvious cartilage and meniscus degeneration were observed at 6 months postoperation. In conclusion, these results indicated that the new tissue engineering scaffold can promote ACL regeneration and slow down the progression of osteoarthritis, thus suggesting its high clinical potential as an ideal graft in ACL reconstruction.

Rates of Adverse Outcomes and Revision Surgery After Anterior Cruciate Ligament Reconstruction: A Study of 104,255 Procedures Using the National Hospital Episode Statistics Database for England, UK

BACKGROUND

After an anterior cruciate ligament (ACL) injury, ACL reconstruction is an elective procedure, and therefore, an understanding of the attributable risk from undergoing ACL reconstruction is necessary for patients to make a fully informed treatment decision.

PURPOSE

To determine the absolute risk of adverse outcomes including reoperation after ACL reconstruction with comparison, where possible, to the rate of adverse events reported in the general population.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

National hospital data on all ACL reconstructions performed in England between April 1, 1997, and March 31, 2017, were analyzed. Revision cases, bilateral procedures within 6 months, and cases with concurrent cartilage or multiple ligament surgery were excluded. The primary outcome was the occurrence of at least 1 serious complication (myocardial infarction, stroke, pulmonary embolism, infection requiring surgery, fasciotomy, neurovascular injury, or death) within 90 days. Additionally, 5-year rates of revision ACL reconstruction, contralateral ACL reconstruction, and meniscal surgery were investigated.

RESULTS

There were 133,270 ACL reconstructions performed, of which 104,255 were eligible for analysis. Within 90 days, serious complications occurred in 675 (0.65% [95% CI, 0.60-0.70]), including 494 reoperations for infections (0.47% [95% CI, 0.43-0.52]) and 129 for pulmonary embolism (0.12% [95% CI, 0.10-0.15]). Of 54,275 procedures with at least 5 years' follow-up, 1746 (3.22% [95% CI, 3.07-3.37]) underwent revision ACL reconstruction in the same knee, 1553 underwent contralateral ACL reconstruction (2.86% [95% CI, 2.72-3.01]), and 340 underwent meniscal surgery (0.63% [95% CI, 0.56-0.70]). The overall risk of serious complications fell over time (adjusted odds ratio [OR], 0.96 per year [95% CI, 0.95-0.98]); however, older patients (adjusted OR, 1.11 per 5 years [95% CI, 1.07-1.16]) and patients with a greater modified Charlson Comorbidity Index (adjusted OR, 2.41 per 10 units [95% CI, 1.65-3.51]) were at a higher risk. For every 850 (95% CI, 720-1039) ACL reconstructions, 1 pulmonary embolism could be provoked. For every 213 (95% CI, 195-233), 1 native knee joint infection could be provoked.

CONCLUSION

The overall risk of adverse events after ACL reconstruction is low; however, some rare but serious complications, including infections or pulmonary embolism, may occur. Around 3% of patients undergo further ipsilateral or contralateral ACL reconstruction within 5 years. These data will inform shared decision making between clinicians and patients considering their treatment options.

The Complex Relationship Between In Vivo ACL Elongation and Knee Kinematics During Walking and Running

In vivo anterior cruciate ligament (ACL) bundle (anteromedial bundle [AMB] and posterolateral bundle [PLB]) relative elongation during walking and running remain unknown. In this study, we aimed to investigate in vivo ACL relative elongation over the full gait cycle during walking and running. Ten healthy volunteers walked and ran at a self-selected pace on an instrumented treadmill while biplane radiographs of the knee were acquired at 100 Hz (walking) and 150 Hz (running). Tibiofemoral kinematics were determined using a validated model-based tracking process. The boundaries of ACL insertions were identified using high-resolution magnetic resonance imaging (MRI). The AMB and PLB centroid-to-centroid distances were calculated from the tracked bone motions, and these bundle lengths were normalized to their respective lengths on MRI to calculate relative elongation. Maximum AMB relative elongation during running (6.7 ± 2.1%) was significantly greater than walking (5.0 ± 1.7%, p = 0.043), whereas the maximum PLB relative elongation during running (1.1 ± 2.1%) was significantly smaller than walking (3.4 ± 2.3%, p = 0.014). During running, the maximum AMB relative elongation was significantly greater than the maximum PLB relative elongation (p < 0.001). ACL relative elongations were correlated with tibiofemoral six degree-of-freedom kinematics. The AMB and PLB demonstrate similar elongation patterns but different amounts of relative elongation during walking and running. The complex relationship observed between ACL relative elongation and knee kinematics indicates that ACL relative elongation is impacted by tibiofemoral kinematic parameters in addition to flexion/extension. These findings suggest that ACL strain is region-specific during walking and running. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1920-1928, 2019.

Patient and Parent Perceptions of Rehabilitation Factors That Influence Outcomes After Anterior Cruciate Ligament Reconstruction and Clearance to Return to Sport in Adolescents and Young Adults

BACKGROUND

Wide variation in outcomes after anterior cruciate ligament reconstruction (ACLR) exists among adolescents and young adults. However, little evidence is available regarding key rehabilitation factors that may be driving these differences.

OBJECTIVE

To explore patient and parent perceptions of key rehabilitation drivers related to outcomes after ACLR.

METHODS

In this qualitative study, which used an interpretive phenomenological methodology, semi-structured interviews were conducted with patients who had returned to sport after ACLR and with their parents. The interviews asked about respondents' experience with physical therapy and how it related to their outcomes after ACLR. The interviews were recorded, transcribed, and coded. Themes were then identified using open and axial coding processes.

RESULTS

There were 3 primary themes that patients and parents perceived as key factors influencing their rehabilitation outcomes after ACLR: (1) patient attributes (ie, motivation, confidence, accountability, access to resources, and social support), (2) physical therapist-patient relationship qualities (physical therapist as guide, motivator, booster of confidence, fosterer of perseverance, and coordinator of care), and (3) elements of the system (ie, availability and utilization of therapy visits, clinic environment, and coordination among care providers).

CONCLUSION

Patient and parent perspectives of key drivers that influence ACLR rehabilitation outcomes include patient, therapist, and system factors. Developing specific strategies to target these factors may enhance patient and parent perceptions of the experience. The awareness gained from these results provides a foundation for future studies examining how these factors affect outcomes and how to improve rehabilitation after ACLR.

LEVEL OF EVIDENCE

Therapy, level 3. J Orthop Sports Phys Ther 2019;49(8):576-583. Epub 13 Feb 2019. doi:10.2519/jospt.2019.8608.

Outcome After Anterior Cruciate Ligament Revision

PURPOSE OF REVIEW

To describe the current literature related to anterior cruciate ligament (ACL) revision in terms of surgical aspects, graft choices, concomitant injuries, patient-reported outcome, return to sport, and objective measurement outcome.

RECENT FINDINGS

An ACL rupture is a common knee injury, and the number of primary ACL reconstructions is increasing, implying a subsequent increase of ACL revisions in the future. It is widely accepted that an ACL revision is surgically challenging with a myriad of graft options to choose from. In many cases, simultaneous injuries to the index limb including meniscal and chondral lesions, respectively, are observed in the setting of a secondary ACL injury. Furthermore, the general understanding is that an ACL revision results in inferior outcome compared with a primary ACL reconstruction. Surgical treatment of an ACL revision can be performed as one-stage or two-stage procedure depending on, for example, the presence of limb malalignments, concomitant injuries, and tunnel widening. Nonirradiated allografts and autologous patella tendon, hamstring tendon, and quadriceps tendon are feasible options for ACL revision. Concomitant injuries to the affected knee such as intraarticular chondral lesions are more common in the setting of an ACL revision compared with primary ACL reconstruction while a lower presence of concomitant meniscal pathology is reported at ACL revision. Patients undergoing ACL revision have lower clinical and patient-reported outcome and lower rates of return to sport when compared with primary ACL surgery cases. However, long-term follow-ups with large study cohorts evaluating outcome of ACL revision are limited. Further research is needed to confirm the present findings of this review.

Anterior cruciate ligament (ACL) reconstruction and meniscal repair rates have both increased in the past 20 years in England: hospital statistics from 1997 to 2017

Objectives

We investigated the temporal trend and the geographical variation in the rate of an anterior cruciate ligament (ACL) reconstruction and meniscal repair (MR) performed in England during a 20-year window.

Methods

All hospital episodes for patients undergoing ACL reconstruction or MR between 1 April 1997 and 31 March 2017 were extracted by procedure code from the national hospital episode statistics. Age-standardised and sex-standardised rates of surgery were calculated using Office for National Statistics population data as the denominator and analysed over time both nationally and regionally by National Health Service clinical commissioning group (CCG).

Results

Between 1997–1998 and 2016–2017, there were 133 270 cases of ACL reconstruction (124 489 patients) and 42 651 cases of MR (41 120 patients) (isolated or simultaneous). Nationally, the rate of ACL reconstruction increased 12-fold from 2.0/100K population (95% CI 1.9 to 2.1) in 1997–1998 to 24.2/100K (95% CI 23.8 to 24.6) in 2016–2017. The rate of MR increased more than twofold from 3.0/100K (95% CI 2.8 to 3.1) in 1997–1998 to 7.3/100K (95% CI 7.1 to 7.5) in 2016–2017. Of these cases, the rate of simultaneous ACL reconstruction and MR was 2.6/100K (95% CI 2.5 to 2.8) in 2016/2017. In 2016–2017, for patients aged 20–29, the sex-standardised rate of ACL reconstruction was 76.9/100K (95% CI 74.9 to 78.9) and for MR was 19.8/100K (95% CI 18.8 to 20.9). Practice varied by region—in 2016–2017, 14.5% (30/207) of the CCGs performed more than twice the national average rate of ACL reconstruction and 15.0% (31/207) performed more than twice the national average rate of MR.

Conclusions

The rate of ACL reconstruction (12-fold) and MR (2.4-fold) has increased in England over the last two decades. There is variation in these rates across geographical regions and further work is required to deliver standardised treatment guidance for appropriate use.