Association Between Transtibial Meniscus Root Repair and Rate of Meniscal Healing and Extrusion on Postoperative Magnetic Resonance Imaging: A Prospective Multicenter Study

Background:

Prospective studies evaluating second-look imaging of meniscus root repair using a transtibial pull-out technique are limited; therefore, optimal surgical indications and the technique for meniscus root repair remain uncertain.

Hypothesis:

It was hypothesized that there would be a high rate of healing, improvement in meniscal extrusion, and prevention of articular cartilage degeneration and subchondral bone abnormalities after meniscus root repair.

Study Design:

Case series; Level of evidence, 4.

Methods:

Consecutive patients undergoing transtibial root repair were prospectively enrolled at 2 orthopaedic centers between March 2017 and January 2019. Pre- and postoperative magnetic resonance imaging (MRI) scans were reviewed by a musculoskeletal radiologist in a blinded fashion for meniscal healing, quantification of extrusion, articular cartilage grade, subchondral bone changes, and coronary/meniscotibial ligament abnormalities. Given persistent extrusion observed on postoperative MRI scans, an additional 10 patients gave consent and were enrolled for immediate (before weightbearing) postoperative MRI scans.

Results:

A total of 45 patients (16 male, 29 female; mean ± standard deviation age, 42.3 ± 12.9 years; body mass index, 31.6) were prospectively enrolled in the study; there were 47 meniscus root repairs: 29 medial and 18 lateral (2 with both). Postoperative MRI was obtained at an average of 6.3 months (range, 5.1-8 months); 98% of meniscal repairs had evidence of healing. Mean extrusion increased significantly, from 1.9 ± 1.5 mm preoperatively to 2.6 ± 1.4 mm postoperatively (P = .03). There was no significant progression of chondromalacia grade, subchondral edema, insufficiency fracture, subchondral cysts, or subchondral collapse. In the additional 10-patient cohort, the mean preoperative extrusion (1.6 ± 1.2 mm) was not significantly different from that immediately postoperatively (2.0 ± 1.0 mm; P = .23).

Conclusion:

Prospective MRI analysis of transtibial meniscus root repair confirmed a high rate of meniscal healing and no observable progression of cartilage degeneration or subchondral bone abnormalities at the short-term follow-up. However, meniscal extrusion worsened in the first 6 months after surgery.

Registration:

NCT03037242 (ClinicalTrials.gov identifier).

Impact of Medial Meniscotibial Ligament Disruption Compared to Peripheral Medial Meniscal Tear on Knee Biomechanics

Medial meniscotibial ligament (MTL) lesions may go unrecognized and untreated and have detrimental impact on knee biomechanics and joint pathology. Therefore, this study was designed to compare the biomechanical impact of midbody MTL disruption to corresponding peripheral medial meniscal (PMM) tears in anterior cruciate ligament (ACL) intact and ACL-deficient cadaveric knees. Cadaveric knees (n = 12; 6 matched pairs) were tested for laxity and ACL strain under anterior, valgus, and external rotation loading at 0, 30, and 90 degree of flexion. Knees were randomly assigned to ACL-intact (n = 6) or ACL-deficient (n = 6) groups. Large midbody MTL disruption or corresponding PMM tears were created (n = 3/group) and knees retested. PMM tears were repaired arthroscopically with inside-out suturing, and MTL lesions were repaired with suture anchors via an open approach. Knees were retested after repair. Biomechanical testing data were compared for statistically significant differences. Large MTL and PMM lesions were associated with significant increases in ACL strain, anterior laxity at 0, 30, and 90 degrees (p = 0.006), valgus laxity (p = 0.0012), and external rotation laxity (p = 0.0003) compared with intact knees. Repair of each lesion restored knee stability and reduced ACL strain to intact levels. In ACL-deficient knees, there was significantly increased anterior, valgus, and external rotation laxity compared with the ACL-intact state and MTL and PMM lesions further increased laxity at all angles. However, differences were not statistically significant and repair of meniscal lesions alone did not restore stability to ACL-deficient knees. These results highlight the need to recognize medial MTL injury and perform an appropriate repair procedure to restore knee stability and protect against excessive ACL strain.

Editorial Commentary: Repair the Anterior Cruciate Ligament When You Can: Add Suture Tape Augmentation and Dress for Success

Preserving the native anterior cruciate ligament (ACL) through primary repair has seen a resurgence over the past few years-rightfully so-given the inherent advantages of repairing the ACL over reconstruction. The issue is how best to repair the ACL and protect it to optimize healing. Suture tape augmentation techniques have shown promising low failure rates, and recent biomechanical studies have demonstrated benefits of the suture tape and optimal fixation methods for ACL repair. So, I believe it is time for orthopaedic surgeons to strongly consider routine suture tape augmentation use for improved outcomes with primary ACL repair.

Self-Tensioning Feature of Knotless Suture Anchor Provides Reproducible Knotless Fixation Independent of Initial Tension

Background:

Anterior cruciate ligament (ACL) reconstruction with suture tape reinforcement has been shown to biomechanically reduce elongation and increase ultimate strength. However, the amount and consistency of the achieved tension after primary fixation using knotless suture anchors remains unclear.

Purpose:

To determine whether initial tensioning of suture tape before fixation with a knotless suture anchor significantly affects final tension of the suture tape.

Study Design:

Controlled laboratory study.

Methods:

We secured 15 pairs of Sawbones blocks with predrilled tunnels to a tensile testing machine. Suture tape was inserted through a suspensory fixation button on the representative femoral block and threaded top-down through the base of the tibial block over an attachable button system. The suture tape was attached with a knotless suture anchor in a predrilled and tapped hole on the tibial block under the following pretensioning conditions: (1) slight tension of 5 N, (2) no tension, and (3) initial slack. The suture anchor was inserted as the load-time data were recorded. After initial block testing, a porcine model of 24 tibias was used to test the same pretensioning conditions. The initial loads during anchor insertion and screw-in were measured, as well as final tension.

Results:

During block testing, no difference in final tensioning was found when comparing the slight-tension, no-tension, and slack groups (42.3 ± 5.3, 37.7 ± 6.4, and 40.2 ± 7.0 N, respectively; P = .528). Similar to block testing, no difference in final tensioning was found when comparing the slight-tension, no-tension, and slack groups using the porcine model (43.64 ± 6.69, 48.09 ± 13.93, and 44.52 ± 6.84 N, respectively; P = .633).

Conclusion:

The final tension of the suture tape construct appears to be reproducible and consistent, independent of the initial tension introduced with suture anchor placement within the tested parameters.

Clinical Relevance:

The results of the current study can help optimize the placement technique of independent suture tape reinforcement for ACL reconstruction, which is a promising strategy to help prevent ACL rerupture, particularly in the early phases of postoperative rehabilitation.

Editorial Commentary: Independent Femoral Tunnel Drilling Avoids Anterior Cruciate Ligament Graft Malpositioning: Advice From a Transtibial Convert

Optimal femoral anterior cruciate ligament graft placement has been extensively studied. The champions of transtibial reconstruction debate the backers of anteromedial portal and outside-in drilling. The holy grail is footprint restoration and how we best to get there. To me, creating the femur independently provides the best chance of finding that footprint by being unconstrained by the tibia. Anterior cruciate ligament surgery is challenging enough; decrease intraoperative stress and increase your likelihood of femoral footprint restoration by drilling it though the anteromedial portal.

Comparison of meniscal allograft transplantation techniques using a preclinical canine model

Meniscal allograft transplantation (MAT) can be a safe, effective treatment for meniscal deficiency resulting in knee dysfunction, leading to osteoarthritis (OA) without proper treatment with 5-year functional success rates (75%-90%). While different grafts and techniques have generally proven safe and effective, complications include shrinkage, extrusion, progression of joint pathology, and failure. The objective of this study was to assess the functional outcomes after MAT using three different clinically-relevant methods in a preclinical canine model. The study was designed to test the hypothesis that fresh meniscal-osteochondral allograft transplantation would be associated with significantly better function and joint health compared with fresh-viable or fresh-frozen meniscus-only allograft transplantations. Three months after meniscal release to induce meniscus-deficient medial compartment disease, research hounds (n = 12) underwent MAT using meniscus allografts harvested from matched dogs. Three MAT conditions (n = 4 each) were compared: frozen meniscus-fresh-frozen meniscal allograft with menisco-capsular suture repair; fresh meniscus-fresh viable meniscal allograft (Missouri Osteochondral Preservation System (MOPS)-preservation for 30 days) with menisco-tibial ligament repair; fresh menisco-tibial-fresh, viable meniscal-tibial-osteochondral allografts (MOPS-preservation for 30 days) with menisco-tibial ligament preservation and autogenous bone marrow aspirate concentrate on OCA bone. Assessment was performed up to 6 months after MAT. Pain, comfortable range of motion, imaging, and arthroscopic scores as well histological and cell viability findings were superior (P < .05) for the fresh menisco-tibial group compared with the two other groups. Novel meniscal preservation and implantation techniques with fresh, MOPS-preserved, viable meniscal-osteochondral allografts with menisco-tibial ligament preservation appears to be safe and effective for restoring knee function and joint health in this preclinical model. This has the potential to significantly improve outcomes after MAT.

Arthroscopic Centralization of the Extruded Medial Meniscus

Tears of the posterior medial meniscus root commonly result in extrusion of the meniscus and disruption of tibiofemoral contact mechanics. Transtibial pull-through repair of the root often results in healing of the tear, but postoperative extrusion may persist. In this scenario, the meniscus is unlikely to be chondroprotective. Therefore, an additional centralization procedure is necessary to improve the extrusion. Biomechanical studies have demonstrated that centralization can improve meniscus mechanics and potentially reduce the risk of osteoarthritis. This Technical Note describes an arthroscopic technique for medial meniscus posterior root repair that combines transtibial pullout and centralization sutures.

Patellar Bone-Tendon-Bone Autografts versus Quadriceps Tendon Allograft with Synthetic Augmentation in a Canine Model

Patellar bone-tendon-bone (pBTB) autografts are often considered the "gold standard" for complete anterior cruciate ligament (ACL) reconstruction and are also associated with significant complications and early-onset knee osteoarthritis (OA). A novel quadriceps tendon allograft with synthetic augmentation, or "internal brace" (QTIB), has been reported to have potential advantages for ACL reconstruction based on animal model data. In this preclinical canine comparison study, we hypothesized that QTIB allograft compared with pBTB autograft would provide superior durability for knee stability, function, and prevention of OA. Under approval from our Institutional Animal Care and Use Committee, adult purpose-bred research hounds (n = 10) underwent arthroscopic complete transection of the ACL followed by either an arthroscopic-assisted all-inside ACL reconstruction using the QTIB allograft (n = 5) or pBTB autograft (n = 5). Contralateral knees were used as nonoperated controls (n = 10). Radiographic and arthroscopic assessments were performed at 2 and 6 months, respectively, after surgery. Anterior drawer, internal rotation, lameness, kinetics, pain, effusion, and comfortable range of knee motion were measured at 2, 3, and 6 months. Biomechanical and histologic assessments were performed at 6 months. All reconstructed knees were stable and had intact ACL grafts 6 months after surgery. At 6 months, QTIB reconstructed knees had significantly less lameness, lower pain, less effusion, and increased range of motion when compared with BTB knees (p < 0.05). BTB knees had significantly higher radiographic OA scores than QTIB knees at 6 months (p < 0.05). Superior outcomes associated with QTIB allograft may be due to the lack of donor site morbidity, the use of a robust tendon graft, and/or protection of the graft from the synthetic augmentation. Robust tendon grafts combined with a synthetic internal brace and platelet-rich plasma (PRP) may allow for more rapid and robust tendon-bone healing and graft "ligamentization," which protects the graft from early failure and rapid OA development that can plague commonly-used allografts.

Initial clinical outcomes comparing frozen versus fresh meniscus allograft transplants

BACKGROUND

To evaluate initial clinical outcomes using fresh meniscal allografts with high cell viability at transplantation time and meniscotibial ligament (MTL) reconstruction (Fresh) in comparison to standard fresh-frozen (Frozen) meniscus allograft transplantation (MAT).

METHODS

Patients treated for medial and/or lateral meniscal deficiency using either Fresh or Frozen MAT with minimum of 1-year follow-up were identified from a prospective registry. Patient demographics, prior surgeries, MAT surgery data, complications, revisions, and failures were documented. Functional outcome scores were collected preoperatively, and 6 months and yearly after surgery and radiographic joint space measurements were performed. Treatment cohorts were compared for statistically significant (P < 0.005) differences using t-Tests and Fisher's exact tests.

RESULTS

Twenty-seven patients (14 Fresh, 13 Frozen) met inclusion criteria and showed comparable characteristics. For Fresh MAT + MTL, 10 medial, two lateral, and two medial + lateral MAT were performed. For Frozen MAT, nine medial, and four lateral MAT were performed. There was significantly more improvement in the Fresh cohort compared to the Frozen cohort for VAS pain (P = 0.014), PROMIS Physical Function (P = 0.036) and Single Assessment Numeric Evaluation (P = 0.033) from preoperatively to 2 years postoperatively. Tegner Activity Scale and PROMIS Mobility score showed no significant differences. The International Knee Documentation Committee score revealed a clinically meaningful change for the Fresh group. Radiographic measurements showed no significant differences between groups. There were two Fresh MAT + MTL revisions and one conversion to TKA in each cohort.

CONCLUSIONS

Fresh MAT + MTL is safe and associated with potential advantages with respect to initial pain relief and function compared to standard frozen MAT.

Independent Suture Tape Internal Brace Reinforcement of Bone-Patellar Tendon-Bone Allografts: Biomechanical Assessment in a Full-ACL Reconstruction Laboratory Model

Internal bracing for anterior cruciate ligament (ACL) surgery is a relatively new concept. The purpose of this study was to evaluate the effects of an "independent" button-fixed internal brace on the biomechanical properties of ACL reconstruction in a full-construct experimental model. Three groups (n = 10 each) were tested in a full-construct porcine-bone model with human bone-patellar tendon-bone allografts using different reconstruction techniques: interference screw fixation on femur and tibia (S-S group), adjustable-loop device (ALD) fixation on the femur with tibial interference screw without suture tape (ALD-S group), and with internal brace (ALD-S-IB group). Measured outcomes included cyclic displacement, stiffness, and ultimate load to failure. The ALD-S-IB group (2.9 ± 0.8 mm) displaced significantly less than the ALD-S (4.2 ± 0.9 mm; p = 0.015) and S-S group (4.3 ± 1.1 mm; p = 0.017). No significant difference was found between the ALD-S and the S-S group. Construct stiffness was significantly higher for the ALD-S-IB group (156 ± 23 N/mm) and the ALD-S group (122 ± 28 N/mm) than for the S-S group (104 ± 40 N/mm; p = 0.003 and p = 0.0042), but there was no significant difference between both ALD groups. Similarly, ultimate loads in the ALD-S-IB (758 ± 128 N) and the ALD-S groups (628 ± 223 N) were significantly greater than in the S-S group (416 ± 167 N; p < 0.001 and p = 0.025), but there was no significant difference between ALD groups. Adding an internal brace reinforcement to an ALD in a full-construct experimental model significantly decreased cyclic displacement by 31% without increasing construct stiffness or ultimate load significantly. These results indicate that suture tape internal bracing of bone-patellar tendon-bone allograft ACL reconstruction decreases cyclic displacement during experimental testing, which has clinical implications regarding initial construct stability.

Knee Ultrasonography to Determine Risk for Noncontact Injuries in Collegiate American Football Players

Knee ultrasonography has been used effectively as a screening tool for determining risk for knee injuries in athletes. Ultrasonography may be a valuable screening tool for relative risk of noncontact knee injuries that occur over a typical playing career in collegiate American football players. In this prospective longitudinal study, we evaluated American football players (n = 48) in an academic institution affiliated with the National Collegiate Athletic Association Division I athletic program. Players underwent comprehensive ultrasonography of both knees prior to beginning their collegiate careers. Anatomic structures were evaluated for presence and severity of abnormalities. Noncontact lower extremity injuries sustained over the collegiate career of the subjects were documented. Data were analyzed for correlations, differences in proportions, and odds ratio (OR). Seventy-nine percent of the athletes had at least one ultrasonographic abnormality, with quadriceps tendon (47.9%) and patellar tendon (39.6%) abnormalities predominating. Seventy-nine percent of players had at least one noncontact lower extremity injury (23.5% involving the knee) during their careers with an average of 2.8 injuries per career. The majority of injuries occurred in the second and third playing years. There was a significantly higher likelihood of patellar tendon injury based on the presence of patellar tendon ultrasonographic pathology (p = 0.024; OR = 11x). There was a significantly higher likelihood of quadriceps muscle-tendon injury based on the presence of quadriceps tendon ultrasonography pathology (p = 0.0012; OR = 140x). All athletes sustaining meniscal injuries had preexisting joint effusion but no preexisting ultrasonographic meniscal pathology. Knee ultrasonography along with patient history and complete physical examination may help reduce injury risk through education, prevention, and training programs.

The visualisation of fingermarks on Pangolin scales using gelatine lifters

Recent media reports document the plight of the Pangolin and its current position as "the most trafficked mammal in the world". They are described by some as scaly anteaters as all species are covered in hard keratinous tissue in the form of overlapping scales acting as a "flexible dermal armour". It is estimated that between 2011 and 2013, 117,000-234,000 pangolins were slaughtered, but the seizures may only represent as little as 10% of the true volume of pangolins being illegally traded. In this paper, methods to visualise fingermarks on Pangolin scales using gelatine lifters is presented. The gelatine lifters provide an easy to use, inexpensive but effective method to help wildlife crime rangers across Africa and Asia to disrupt the trafficking. The gelatine lifting process visualised marks producing clear ridge detail on 52% of the Pangolin scales examined, with a further 30% showing the impression of a finger with limited ridge detail. The paper builds on an initial sociotechnical approach to establishing requirement, then it focuses on the methods and outcomes relating to lifting fingermarks off Pangolin scales using gelatine lifters, providing an evaluation of its use in practice.

All-Inside Quadrupled Semitendinosus Autograft Shows Stability Equivalent to Patellar Tendon Autograft Anterior Cruciate Ligament Reconstruction: Randomized Controlled Trial in Athletes 24 Years or Younger

PURPOSE

To compare clinical outcomes of knee anterior cruciate ligament (ACL) autograft reconstruction using all-inside quadrupled semitendinosus (AIST) versus bone-patellar tendon-bone (BPTB) in a high-risk athletic population 24 years or younger.

METHODS

Skeletally mature candidates younger than 24 years old with an ACL tear were randomized into either the AIST (n = 32) or BPTB (n = 32) group and were followed for 2 years. Magnetic resonance imaging scans were obtained at 1-year follow-up, and radiographs were obtained at 2-year follow-up. All surgeries were performed by a single surgeon using an anteromedial portal to establish the femoral tunnel. The primary outcome measure was KT-1000 stability testing. Secondary outcome measures included International Knee Documentation Committee (IKDC) Knee Evaluation Form, IKDC Subjective Form, Knee Injury and Osteoarthritis Outcome Score, Marx Activity Scale, visual analog pain scale, and SF-12 (Mental and Physical).

RESULTS

At 2-year follow-up, no statistical difference existed with KT-1000-measured side-to-side laxity between AIST (0.3 ± 0.7 mm, 95% confidence interval 0.0-1.0 mm) and BPTB (0.0 ± 0.8 mm, confidence interval CI -0.3 to 1.1 mm) (P = .197). In addition, no statistical differences between the groups were found for IKDC Subjective Form, Knee Injury and Osteoarthritis Outcome Score, Marx, SF-12 Mental, SF-12 Physical, or with regards to imaging findings. Patients with BPTB reported significantly greater postoperative pain scores at days 2 (P = .049), 3 (P = .004), and 7 (P = .015) and had significantly greater kneeling pain at 2 years (P < .019). A return to sport questionnaire at 2 years revealed no significant difference between the groups for returning to preoperative level of sport activity (83% AIST, 74% BPTB; P = .415). Two graft retears (7%; P = .222) occurred in the AIST group. Three patients in the BPTB group experienced ACL tears in the contralateral knee (9%; P = .239).

CONCLUSIONS

ACL reconstruction with an all-inside quadrupled semitendinosus autograft construct is equivalent to patellar BPTB autograft based on KT-1000 stability testing in athletes 24 years or younger.

LEVEL OF EVIDENCE

randomized controlled trial with 92% 2-year follow-up, Level I.

Lateral Meniscal Oblique Radial Tears Are Common With ACL Injury: A Classification System Based on Arthroscopic Tear Patterns in 600 Consecutive Patients

Background:

Meniscal root tears and ramp lesions have been rigorously characterized in recent literature. However, one of the most common lateral meniscal injuries identified with an acute anterior cruciate ligament (ACL) disruption, a posterior horn lateral meniscal oblique radial tear (LMORT), has not been thoroughly described.

Purpose:

To determine the incidence of all meniscal tears and, more specifically, the incidence of posterior horn LMORTs in a multicenter cohort of consecutive, acute ACL reconstructions. Additionally, the authors aimed to develop a new classification system to help guide treatment of posterior horn LMORTs.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

A multicenter retrospective cohort design was used to analyze 200 consecutive cases of acute ACL reconstruction from each of 3 different surgeons, for a total of 600 patients. The operative notes and intraoperative photos were analyzed to determine the incidence and laterality of all meniscal tears. A classification system based on tear characterization was then used to categorize tear patterns into similar groups.

Results:

A total of 396 (66%) of the 600 patients with acute ACL disruption had concomitant meniscal tears. Specifically, 187 (31%) had a lateral meniscal injury, 89 (15%) had a medial meniscal injury, and 122 (20%) had both medial and lateral meniscal injuries. The most common lateral meniscal tear was an LMORT; 71 (18%) patients with meniscal tears had a posterior horn LMORT. Overall, the incidence of ACL injury with a concomitant posterior horn LMORT was 12%. A classification was developed, which included type 1 tear (partial thickness <10 mm from the root attachment), type 2 tear (complete radial oblique tear that extended <10 mm from root), type 3 tear (incomplete LMORT that extended >10 mm from root), and type 4 tear (complete LMORT >10 mm from root).

Conclusion:

In 600 consecutive acute ACL reconstructions, the incidence of concomitant ACL injury with meniscal injury was 66%, and posterior horn LMORTs represented a large proportion of all meniscal tears (12%). A classification scheme was developed for posterior horn LMORTs to aid reporting and clinical decision making for these common tears.

Treatment of Acute Proximal Anterior Cruciate Ligament Tears-Part 1: Gap Formation and Stabilization Potential of Repair Techniques

Background:

Recently, there has been a resurgence of interest in primary repair of the anterior cruciate ligament (ACL), with fixation techniques evolving. However, to date, there have been no biomechanical studies comparing fixed to adjustable fixation repair techniques.

Hypothesis:

Adjustable ACL repair provides for improved stabilization compared with fixed techniques with respect to both gap formation and residual load-bearing capability.

Study Design:

Controlled laboratory study.

Methods:

A total of 4 different ACL repair techniques (n = 5 per group), including single– and double–cinch loop (CL) cortical button fixation as well as knotless single–suture anchor fixation, were tested using a porcine model. For adjustable single-CL loop fixation, additional preconditioning (10 cycles at 0.5 Hz) was performed. The force after fixation and the actuator displacement to achieve a time-zero preload of 10 N were measured for fixed techniques. Incrementally increasing cycling (1 mm/500 cycles) from 1 to 8 mm was performed for 4000 cycles at 0.75 Hz before pull to failure (50 mm/min). The final residual peak load and gap formation for each test block were analyzed as well as ultimate strength.

Results:

Knot tying of a single-CL over a button (mean ± SD, 0.66 ± 0.23 mm) and knotless anchor fixation (0.20 ± 0.12 mm) resulted in significant time-zero gaps (P < .001) and significantly higher overall gap formation at reduced residual loading (analysis of covariance, P < .001) compared with both the double-CL loop and adjustable fixation techniques. The adjustable group showed the highest failure load and stiffness, at 305.7 N and 117.1 N/mm, respectively. The failure load of the knotted single-CL group was significantly reduced compared with all other groups (P < .001).

Conclusion:

Adjustable single-CL cortical button fixation with intraoperative preconditioning optimized time-zero ACL tension and led to significantly improved stabilization and reduced gap formation, with the highest ultimate strength. Single-CL loop knot tying over the button and knotless anchor fixation resulted in time-zero gaps to achieve slight tension on the ACL and significantly higher gap formation at reduced load-bearing capability.

Clinical Relevance:

Although the clinical relevance of gap formation is uncertain, a biomechanical understanding of the stabilization potential of current ACL repair techniques is pertinent to the continued evolution of surgical approaches to enable better clinical outcomes.

Treatment of Acute Proximal Anterior Cruciate Ligament Tears-Part 2: The Role of Internal Bracing on Gap Formation and Stabilization of Repair Techniques

BACKGROUND

The latest biomechanical studies on some form of internal bracing have shown improved stabilization for anterior cruciate ligament (ACL) repair, but gap formation and load-sharing function have not yet been reported.

HYPOTHESIS

Internal bracing of an adjustable ACL repair construct provides improved stabilization with reduced gap formation and higher residual loading on the ACL.

STUDY DESIGN

Controlled laboratory study.

METHODS

Internally braced ACL repair constructs with single- and double-cinch loop (CL) cortical buttons, a knotless suture anchor, and a single-CL cortical button with adjustable loop fixation (CLS-ALD) were tested (n = 20 each) in a porcine model at 4 different loads (n = 5 each) over 4000 cycles at 0.75 Hz (n = 80 total). The CLS-ALD technique allowed for additional preconditioning (10 cycles at 0.5 Hz). Test results of the isolated internal brace groups served as a baseline for comparison. Lastly, specimens were pulled to failure (50 mm/min) with a cut internal brace. Final loading and gap formation on the ACL repair construct as well as ultimate strength were analyzed.

RESULTS

A statistical significance for peak loads over peak elongation was found between the CLS-ALD and all other reinforced groups (analysis of covariance, P < .001). Accordingly, the adjustable repair technique showed improved load-bearing capability with the internal brace compared with all other fixed repair groups and revealed significantly higher loads than the knotted single-CL group. Also, significantly reduced gap formation was found for the CLS-ALD compared with all other groups (P < .001), with no gap formation up to 150 N with a final gap of 0.85 ± 0.31 mm at 350 N. A significantly higher ultimate failure load (866.2 ± 104.0 N; P < .001) was found for the button-fixed internal brace group compared with all other groups.

CONCLUSION

Internal bracing had a crucial role in improving the stabilization potential of ACL repair at loads occurring during normal daily activity. The added strength of the internal brace allowed for reducing peak loads on the ACL repair construct as well as restricting gap formation to below 3 mm at loads up to 350 N.

CLINICAL RELEVANCE

Improvements in the mechanical characteristics of current ACL repair techniques that enable reduced gap formation and allow for early range of motion and accelerated rehabilitation may strengthen the self-healing response with the formation of stable scar tissue.

Editorial Commentary: Anterior Cruciate Ligament Graft Reinforcement: A New Era Supported by Science

The use of suture tape for soft tissue reinforcement during anterior cruciate ligament surgery is amassing science from translational models to bench biomechanical studies and now clinical outcomes. Suture tape reinforcement is not a synthetic ligament replacement. The primary goal of adding suture tape is for anterior cruciate ligament graft protection during the healing and remodeling phase, especially in young, active patients, to minimize the risk of graft retears. Accepting new techniques requires critical review of available science, as well as an inherent belief that there always is a better way. New technology supported by foundational scientific evidence and focused medical education is essential for successful clinical outcomes.

Intra-Articular Biocompatibility of Multistranded, Long-Chain Polyethylene Suture Tape in a Canine ACL Model

The purpose of this study was to assess intra-articular use of a nonabsorbable braided suture tape for its biocompatibility when implanted adjacent to the native anterior cruciate ligament (ACL) in a canine model. Establishing biocompatibility of suture tape in the knee is an important foundational step for clinicians considering use of suture tape augmentation for ACL reconstruction or repair. The study hypothesis was that a nonabsorbable braided suture tape would be biocompatible in the knee with no resultant adverse functional consequences, and no significant intra-articular synovial reactions or articular cartilage degeneration attributable to direct exposure to the suture tape, whether intact or transected. Nonabsorbable braided suture tape was arthroscopically implanted adjacent to the native ACL of dogs (n = 6). The suture was intact in half of the dogs and was transected in the other half as a "worst-case" scenario. Dogs were assessed for postoperative complications and morbidity. Arthroscopic grading of synovium and cartilage was performed at 4 and 6 months. Histologic assessments were performed at the 6-month endpoint and compared with the ACL partial tear (n = 9) and ACL reconstruction (n = 5) cohorts as well as historical sham controls. No postoperative complications were noted. No animal developed lameness or clinical dysfunction, and there were no severe inflammatory or immune responses, cartilage erosions, or premature osteoarthritis noted. Arthroscopic assessments revealed no to mild synovitis and no apparent cartilage damage in either group. Histologically, both the intact and transected suture tape groups were associated with significantly (p ≤ 0.05) less synovial and articular cartilage pathology compared with the partial ACL transection and patellar bone-tendon-bone ACL autograft reconstruction cohorts, and matched historical sham controls. The hypothesis was accepted as study results support the biocompatibility of suture tape in the canine knee.

A Biomechanical Study of the Role of the Anterolateral Ligament and the Deep Iliotibial Band for Control of a Simulated Pivot Shift With Comparison of Minimally Invasive Extra-articular Anterolateral Tendon Graft Reconstruction Versus Modified Lemaire Reconstruction After Anterior Cruciate Ligament Reconstruction

PURPOSE

To determine whether the deep fibers of the iliotibial band (dITB) or the anterolateral ligament (ALL) provides more control of a simulated pivot shift and whether a minimally invasive anterolateral reconstruction (ALR) designed to functionally restore the ALL and dITB is mechanically equivalent to a modified Lemaire reconstruction (MLR).

METHODS

Six matched pairs of cadaveric knees (N = 12) were subjected to a simulated pivot shift to evaluate anteroposterior translation; internal rotation; and valgus laxity at 0°, 30°, and 90° of flexion. The anterior cruciate ligament (ACL) was sectioned in all specimens, and retesting was performed. Within each pair, sequential sectioning of the ALL and dITB was performed, followed by testing; the contralateral knee was sectioned in reverse order. Knees underwent ACL reconstruction (ACLR) and repeat testing. Then, MLR (n = 6) or ALR (n = 6) was performed on matched pairs for final testing.

RESULTS

Sectioning of the dITB versus ALL (after ACL sectioning) produced significantly more anterior translation at all flexion angles (P = .004, P = .012, and P = .011 for 0°, 30°, and 90°, respectively). The ACL-plus-dITB sectioned state had significantly more internal rotation at 0° versus ACL plus ALL (P = .03). ACLR plus ALR restored native anterior translation at all flexion angles. ACLR plus MLR restored anterior translation to native values only at 0° (P = .34). We found no statistically significant differences between ACLR plus ALR and ACLR plus MLR at any flexion angle for internal rotation or valgus laxity compared with the native state.

CONCLUSIONS

ALR of the knee in conjunction with ACLR can return the knee to its native biomechanical state without causing overconstraint. The dITB plays a more critical role in controlling anterior translation and internal rotation at 0° than the ALL. The minimally invasive ALR was functionally equivalent to MLR for restoration of knee kinematics after ACLR.

CLINICAL RELEVANCE

The dITB is more important than the ALL for control of the pivot shift. A minimally invasive extra-articular tendon allograft reconstruction was biomechanically equivalent to a modified Lemaire procedure for control of a simulated pivot shift.

Biomechanical Testing of Three Alternative Quadrupled Tendon Graft Constructs With Adjustable Loop Suspensory Fixation for Anterior Cruciate Ligament Reconstruction Compared With Four-Strand Grafts Fixed With Screws and Femoral Fixed Loop Devices

BACKGROUND

Quadrupled semitendinosus (ST) grafts for anterior cruciate ligament (ACL) reconstruction have advantages of greater graft diameter and gracilis (G) preservation compared with doubled ST-G grafts. However, a paucity of biomechanical data are available regarding different preparation techniques for these constructs.

PURPOSE

To biomechanically analyze 3 alternative tendon constructs fixed with adjustable suspensory fixation devices on the femur and tibia compared with a matched 4-strand construct fixed with a tibial screw and femoral fixed loop device.

STUDY DESIGN

Controlled laboratory study.

METHODS

Three alternative quadrupled tendon preparation techniques with suspensory fixation (grafts constructs A, B, and C) were compared with a 4-strand screw-fixed loop device construct (graft construct D) in matched diameter bovine tendon graft and porcine tibia models. Graft constructs were tested with a 3-stage cyclic loading protocol (1000 cycles in position control and 1000 cycles each from 10 to 250 N and from 10 to 400 N), followed by a pull to failure. In graft construct A, the graft ends were whipstitched and tied over the tibial button; in graft construct B, the graft ends functioned as pulleys; and in graft construct C, a continuous loop was created. Initial, dynamic, and total elongation, stiffness, and ultimate failure load were recorded.

RESULTS

Graft construct D had the highest initial (0.51 ± 0.29 mm) and total (3.53 ± 0.98 mm) elongation compared with the 3 quadrupled constructs ( P < .001 each). Graft construct B had lower total elongation (2.13 ± 0.31 mm) compared with graft construct A (2.40 ± 0.30 mm) ( P = .004) and graft construct C (2.53 ± 0.21 mm) ( P = .007). Graft construct C had a higher ultimate failure load (1097 ± 79 N) compared with graft construct A (988 ± 112 N) ( P = .001), graft construct B (973 ± 137 N) ( P = .022), and graft construct D, which had the lowest failure load (767 ± 182 N) ( P < .001).

CONCLUSION

The 3 quadrupled tendon suspensory fixation constructs exhibited small yet statistically significant biomechanical differences among each other. Constructs that used tibial screw fixation had lower ultimate failure load and higher total elongation compared with the quadrupled tendon constructs.

CLINICAL RELEVANCE

Total elongation for the screw fixation group was higher than the threshold of clinical failure, which may allow for graft construct elongation during the postoperative rehabilitation phase. Biomechanical properties of the 3 quadrupled tendon suspensory graft constructs may be clinically comparable, albeit statistically different.

Clinical Update: Why PRP Should Be Your First Choice for Injection Therapy in Treating Osteoarthritis of the Knee

PURPOSE OF REVIEW

The purpose of this review is to update the reader on the current applications of platelet-rich plasma (PRP) in the treatment of knee osteoarthritis (KOA). This review will focus on PRP's effect on the osteoarthritic joint, how PRP compares to traditional treatments of KOA, and provide clinical feedback on the use of PRP in an orthopedic and sports medicine practice.

RECENT FINDINGS

Recent research into the applications of PRP for KOA has further indicated both the efficacy and safety of PRP treatment. Although research has shown a tendency toward better efficacy at earlier stages of osteoarthritis (OA), evidence exists to indicate positive effects at all stages of OA. In summary, since KOA is an extremely prevalent condition that can be a challenge to treat, it is imperative that safe and effective nonoperative treatment methods be available to individuals that are suffering from this condition.

Adjustable- Versus Fixed-Loop Devices for Femoral Fixation in ACL Reconstruction: An In Vitro Full-Construct Biomechanical Study of Surgical Technique-Based Tibial Fixation and Graft Preparation

Background

Femoral suspensory fixation for anterior cruciate ligament (ACL) reconstruction has evolved from fixed- to adjustable-loop devices. However, there are still controversies regarding undesired lengthening of adjustable-loop devices.

Hypothesis

Adjustable-loop fixation will achieve similar elongation to that of fixed-loop devices, and intraoperative preconditioning will reduce initial elongation for adjustable-loop constructs.

Study Design

Controlled laboratory study.

Methods

Three adjustable-loop devices (GraftMax, TightRope, and Ultrabutton) and 2 fixed-loop devices (Endobutton and RetroButton) were used in an intraoperative surgical technique workflow according to an in vitro model with porcine bone and bovine tendons (8 specimens per device; N = 40 constructs tested). Each construct underwent 1000 cycles of position- and force-controlled dynamic loading, whereby a total elongation threshold of 3 mm was defined as clinical failure. Constructs were finally pulled to failure at 50 mm/min.

Results

There were no statistically significant differences among the devices for total or dynamic elongation. Total elongation (mean ± SD) for adjustable-loop constructs was 4.13 ± 1.46 mm for GraftMax, 2.78 ± 0.85 mm for TightRope, and 2.76 ± 0.45 mm for Ultrabutton; for the fixed-loop devices, total elongation was 2.85 ± 0.74 mm for Endobutton and 2.85 ± 1.03 mm for RetroButton. The GraftMax had a significantly lower initial force (95.5 ± 58.0 N) after retensioning, with the highest initial elongation (0.99 ± 0.60 mm). The Ultrabutton showed the greatest force loss (-105.9 ± 13.5 N) during position control cycling, which was significantly different from the GraftMax (-22.3 ± 28.2 N), with the smallest force loss (P < .001). The TightRope construct had a significantly smaller initial elongation (-0.36 ± 0.22 mm) and the greatest pull-to-failure load (958 ± 40 N) as compared with all of the other devices.

Conclusion

Adjustable- and fixed-loop configurations achieved statistically comparable fixation strength for total elongation. However, the GraftMax construct exceeded the total elongation threshold of clinical failure. The Ultrabutton produced the greatest loss of force during position control cycling, and the GraftMax button design prevented proper retensioning. The TightRope had a significant greater ultimate strength when compared with all other devices.

Clinical Relevance

Biomechanical testing according to a surgical technique workflow suggests that adjustable-loop devices can be considered a safe alternative to fixed-loop devices in ACL reconstruction.