The "ligamentization" process in human anterior cruciate ligament reconstruction with autogenous patellar and hamstring tendons: a biochemical study

Functional outcomes in single stage bilateral ACL reconstruction with a maximum follow up of 10 years

Background

Bilateral ACL injuries are a rarity and there is no particular consensus on whether this rare problem has to be tackled in stages or in a single stage. There are a few studies and case reports in the literature about the outcomes in single staged bilateral Anterior cruciate ligament reconstruction (ACLR). This study is focused on functional outcomes after a single staged bilateral ACLR, as well as impact of simultaneity of the injury, meniscal tears, notch stenosis and hyperlaxity.

Materials and methods

A retrospective study was conducted from 2013 to 2021. Patients with bilateral ACL injury either simultaneous or non simultaneous, with or without meniscal tears were included in this study. Pre operative diagnosis was made both clinically and by MR imaging. All patients underwent a single staged bilateral ACL reconstruction. Pre operative functional scores (IKDC and Lysholm) were taken at admission and patients were examined at regular follow ups. Final functional scores were collected in a phone interview.

Results

33 patients underwent bilateral ACLR in a single stage during the study period but one patient had revision ACLR in one knee and so was excluded. Of the 32 patients, 25 (78%) had non simultaneous injury and 7 (22%) had a simultaneous injury, meniscus tear was noted in 27 (84.4%), notch stenosis in 19 (59.3%) and hyperlaxity in 12 (37.5%). IKDC and Lysholm scores have improved postoperatively. No statistically significant difference was found with or without simultaneous injury or meniscus tears.

Conclusion

Single stage bilateral ACL reconstruction is a safe, reproducible approach to bilateral ACL injuries whether they were simultaneous or non simultaneous or with or without meniscal tears.

Better Safe Than Sorry? A Systematic Review with Meta-analysis on Time to Return to Sport After ACL Reconstruction as a Risk Factor for Second ACL Injury

OBJECTIVE: To compare the time to return to sport (RTS) between patients who did and did not suffer a second anterior cruciate ligament (ACL) injury after ACL reconstruction. DESIGN: Etiology systematic review with meta-analysis. LITERATURE SEARCH: Cochrane Library, Embase, Medline, AMED, and PEDro databases were searched in August 2021 and again in November 2022. STUDY SELECTION CRITERIA: Clinical studies reporting time to RTS after ACL reconstruction and second ACL injury were eligible. DATA SYNTHESIS: We pooled continuous data (time [months] and proportions [%]), with random-effects meta-analyses. Pooled estimates were summarized in forest plots. A qualitative data synthesis was also performed. RESULTS: Twenty-one studies were included in the meta-analysis and 33 in the qualitative synthesis. Pooled incidence of second ACL injury was 16.9% (95% confidence interval [CI]: 12.8, 21.6). Patients who suffered a second ACL injury returned to sport significantly earlier (25 days; 95% CI: 9.5, 40.4) than those who did not suffer another injury. There was no difference in time to RTS for professional athletes who suffered a second ACL injury and those who did not. The certainty of evidence was very low. CONCLUSION: There was very low-certainty evidence that patients who suffered a second ACL injury had returned to sport 25 days earlier than patients who did not have another injury. For professional athletes, there was no difference in time to RTS between athletes who suffered a second ACL injury and athletes who did not. J Orthop Sports Phys Ther 2024;54(3):1-15. Epub 30 November 2023. doi:10.2519/jospt.2023.11977.

Quadriceps tendon autograft is promising with lower graft rupture rates and better functional Lysholm scores than hamstring tendon autograft in pediatric ACL reconstruction. A systematic review and meta-analysis

Purpose

Graft rupture is the most prevalent complication following pediatric anterior cruciate ligament reconstruction (ACLR). The hamstring tendon (HT) autograft is frequently employed, while the quadriceps tendon (QT) autograft has garnered increased attention recently. This study aims to perform a systematic review to assess the complication rates and functional outcomes associated with these two widely used autografts in skeletally immature patients - comparing HT versus QT autografts.

Research question

Is QT autograft better than HT autograft for ACLR in skeletally immature cohorts?

Methodology

Three electronic databases (PubMed/Medline, Scopus, and Ovid) were comprehensively searched to identify pertinent articles reporting the outcomes of HT and QT autografts in pediatric ACLR with a minimum 2-year follow-up. Data on the outcome parameters, such as graft rupture rates, contralateral ACL injury rates, functional outcomes, and growth disturbances rates, were extracted. Meta-analysis was performed using OpenMeta Analyst software.

Results

Twelve studies were included for meta-analysis (pooled analysis) with 659 patients (QT: 205; HT: 454). The analysis showed that QT autografts had a significantly lesser graft rupture rate than HT autografts (3.5 % [95 % CI 0.2, 6.8] and 12.4 % [95 % CI 6.1, 18.7] respectively, p < 0.001). The graft rupture rates between QT with bone and without bone block showed no statistically significant difference (4.6 % [95 % CI 0.8, 1.0] and 3.5 % [95 % CI 2.0, 8.9] respectively, p = 0.181). The overall contralateral ACL injury rate was 10.2 %, and the subgroup analysis revealed no statistically significant difference between the QT and HT groups (p = 0.7). Regarding functional outcome scores at the final follow-up, the mean Lysholm score demonstrated a significant increase in the QT group compared to the HT group (p < 0.001). There were no significant differences between the two groups concerning growth disturbances at the final follow-up. Return to sports (RTS) varied between 6 and 13.5 months after surgery.

Conclusion

QT autografts demonstrate encouraging outcomes, showcasing lower graft rupture rates, better functional outcomes, and comparable contralateral ACL injury rates and growth disturbances relative to the commonly used HT autograft in skeletally immature patients undergoing ACLR.

Clinical and Patient-Reported Functional Outcome of Semitendinosus Autograft Anterior Cruciate Ligament Reconstruction With FiberTape® InternalBrace™ All-Inside Technique: A Prospective Study

AIM

The purpose of this study is to report the early one-year clinical and patient-reported functional outcomes of semitendinosus autograft anterior cruciate ligament reconstruction with the FiberTape® InternalBrace™ all-inside technique.

MATERIALS AND METHODS

The patient-reported functional outcomes and clinical outcomes were analyzed prospectively following the treatment of 324 unilateral ACL rupture cases with the FiberTape® InternalBrace™ Technique. Patient-reported outcome measures (KOOS scores, WOMAC scores, VAS score, and IKDC score) and clinical examinations like pre-operative and post-operative pivot shift, Lachman test, and range of motion (ROM) were conducted. These tests and examinations were recorded for each patient before surgery and at 3, 6, and 12 months after surgery. Secondary outcomes like re-rupture, infection, synovitis, or limited range of motion were noted. The mean follow-up period was 18±4.5 months (range: 12-24 months).

RESULTS

Out of a total of 324 cases, 37 cases (11.4%) could not be followed up. 158 patients (55.1%) were male and 129 were female (44.9%). Preoperative mean KOOS pain value, KOOS symptoms, KOOS ADLs, KOOS sport and recreation, and KOOS quality of life were 77.05, 78.69, 84, 21, 89.7, and 57, respectively. All KOOS subsections increased significantly at one-year to 98.37, 99.09, 98.95, 99.02, and 99.30 (p<0.0001), respectively. Mean preoperative WOMAC pain, WOMAC stiffness, and WOMAC function were 76.4, 65.2, and 74.1 and increased significantly at one-year to 94.5, 89.6, and 98.2 (p<0.0001), respectively. There was a significant decrease in VAS for pain from 2.93 before surgery to 0.12 (p<0.0001) at one year. The IKDC score significantly changed from a pre-treatment value of 50.9 to 96.2 (94.5-97.8) at a follow-up of one year. The Lysholm score at 12-months was significant at 95 (93.1-96.9), p<0.05. Post-operative Lachman test values decreased significantly, which meant decreased laxity, from 1.98 (1.89-2.07) pre-operative to 1.60 (1.57-1.62) p<0.05 at one-year post-operative. At one-year follow-up, 276 patients (96%) had fully recovered.

CONCLUSION

It was concluded that the FiberTape® InternalBrace™ technique for ACL reconstruction provides orthopedic surgeons with an effective alternative technique to conventional methods of surgery and also reduces the overall time to recovery for patients, thereby allowing them to return to sports faster.

LEVEL OF EVIDENCE

Level 4.

Comparison of "ligamentization" process between preserved insertion hamstring tendon autograft and bone-patellar tendon-bone autograft

BACKGROUND

Ligamentization is a complex process and effect of preservation of hamstring tendon graft insertion on this process is not well studied. Present study was conducted to analyze and compare the ligamentization of semitendinosus gracilis graft with preserved tibial insertion (STGPI) and bone-patellar tendon-bone (BPTB) autografts.

METHODS

A total of 50 sportspeople who underwent ACL reconstruction using either BPTB (group A; n = 25) or STGPI (group B; n = 25) autografts were included in the study. Contrast enhanced MRI was done at 8 months and 14 months post-ACL reconstruction to evaluate the ligamentization using Signal noise quotient (SNQ), graft intensity and enhancement index. Clinical outcomes (Lysholm score) and knee laxity were also assessed at 8 months and 14 months.

RESULTS

18/23 (78%) patients in group A and 14/23 (61%) patients in group B had hyperintense graft signal at 8 months (n.s.) and at 14 months, 1/23 patients in group A and none of the patients in group B had hyperintense graft. SNQ at 8 months was 3.6 ± 2 and 3.7 ± 2 in group A and B respectively (n.s.) and at 14 months, SNQ was 2.5 ± 1.5 in group A and 2.4 ± 1.3 in group B (n.s.). Enhancement index at 8 months was 1.5 ± 0.3 and 1.2 ± 0.3 in group A and B respectively (p = 0.0001). Enhancement index at 14 months was 1.21 ± 0.2 in group A and 1.07 ± 0.2 in group B (p = 0.003). Functional outcomes and knee laxity were comparable in both the groups at 8 and 14 months (n.s.).

CONCLUSION

Both the grafts i.e. BPTB and STGPI are similar in terms of rate and extent of ligamentization. Clinical outcomes and knee laxity are also comparable between two grafts.

Does medial patellofemoral ligament reconstruction result in femoral tunnel enlargement? A systematic review

BACKGROUND

Medial patellofemoral ligament (MPFL) reconstruction is a common surgical procedure for treating patellar instability. The primary aim of this systematic review was to determine whether MPFL reconstruction (MPFLR) leads to femoral tunnel enlargement (FTE). The secondary aims were to explore the clinical effects and risk factors of FTE. Electronic databases (MEDLINE, Global Health, Embase), currently registered studies, conference proceedings and the reference lists of included studies were searched independently by three reviewers. There were no constraints based on language or publication status. Study quality assessment was conducted. 3824 records were screened in the initial search. Seven studies satisfied the inclusion criteria, evaluating 380 knees in 365 patients. Rates of FTE following MPFLR ranged from 38.7 to 77.1%. Five low quality studies reported FTE did not lead to detrimental clinical outcomes as assessed with the Tegner, Kujala, IKDC, and Lysholm scores. There is conflicting evidence regarding change in femoral tunnel width over time. Three studies (of which two had a high risk of bias) reported age, BMI, presence of trochlear dysplasia and tibial tubercle-tibial groove distance did not differ between patients with and without FTE, suggesting these are not risk factors for FTE.

CONCLUSION

FTE is a common postoperative event following MPFLR. It does not predispose poor clinical outcomes. Current evidence lacks the ability to identify its risk factors. The reliability of any conclusions drawn is hindered by the low level of evidence of the studies included in this review. Larger prospective studies with long-term follow up are required to reliably ascertain the clinical effects of FTE.

Canine ACL reconstruction with an injectable hydroxyapatite/collagen paste for accelerated healing of tendon-bone interface

Healing of an anterior cruciate ligament (ACL) autologous graft in a bone tunnel occurs through the formation of fibrovascular scar tissue, which is structurally and compositionally inferior to normal fibrocartilaginous insertion and thus may increase the reconstruction failure and the rate of failure recurrence. In this study, an injectable hydroxyapatite/type I collagen (HAp/Col Ⅰ) paste was developed to construct a suitable local microenvironment to accelerate the healing of bone-tendon interface. Physicochemical characterization demonstrated that the HAp/Col Ⅰ paste was injectable, uniform and stable. The in vitro cell culture illustrated that the paste could promote MC3T3-E1 cells proliferation and osteogenic expression. The results of a canine ACL reconstruction study showed that the reconstructive ACL had similar texture and color as the native ACL. The average width of the tunnel, total bone volume, bone volume/tissue volume and trabecular number acquired from micro-CT analysis suggested that the healing of tendon-bone interface in experimental group was better than that in control group. The biomechanical test showed the maximal loads in experimental group achieved approximately half of native ACL's maximal load at 24 weeks. According to histological examination, Sharpey fibers could be observed as early as 12 weeks postoperatively while a typical four-layer transitional structure of insertion site was regenerated at 48 weeks in the experimental group. The injectable HAp/Col Ⅰ paste provided a biomimetic scaffold and microenvironment for early cell attachment and proliferation, further osteogenic expression and extracellular matrix deposition, and in vivo structural and functional regeneration of the tendon-bone interface.

•

A stable and injectable HAp/Col I paste was designed, optimized and characterized.

•

The paste was applied in ACL reconstruction with an established standard operation procedure.

•

Provided the safety and efficacy evidence for ACL reconstruction, and healing of tendon-bone interface was accelerated.

Factors Influencing the Initial Constraint Level of the Knee Joint and Its Effect on Clinical Outcomes After ACL Reconstruction With Hamstring Graft

Background

A force-based tension protocol that uses a certain amount of tension at graft fixation could still give rise to variations in initial constraint levels of the knee joint in terms of side-to-side difference (SSD) in anterior translation.

Purpose

To investigate the factors influencing the initial constraint level in anterior cruciate ligament (ACL)-reconstructed knees and compare outcomes according to the level of constraint in terms of anterior translation SSD.

Study Design

Cohort study; Level of evidence, 3.

Methods

Included were 113 patients who underwent ipsilateral ACL reconstruction using an autologous hamstring graft and had minimum 2-year follow-up outcomes. All grafts were tensioned and fixed at 80 N using a tensioner at the time of graft fixation. The patients were classified into the following 2 groups according to the initial anterior translation SSD, measured using the KT-2000 arthrometer: a physiologic constraint group with restored anterior laxity ≤2 mm (group P; n = 66) and a high-constraint group with restored anterior laxity >2 mm (group H; n = 47). Clinical outcomes were compared between the groups, and preoperative and intraoperative variables were evaluated to identify factors affecting the initial constraint level.

Results

Between group P and group H, generalized joint laxity (P = .005), posterior tibial slope (P = .022), and anterior translation measured in the contralateral knee (P < .001) were found to differ significantly. Measured anterior translation in the contralateral knee was the only significant predictor of high initial graft tension (P = .001). No significant differences were found between the groups regarding clinical outcomes and subsequent surgery.

Conclusion

Greater anterior translation measured in the contralateral knee was an independent predictor of a more constrained knee after ACL reconstruction. The short-term clinical outcomes after ACL reconstruction were comparable, regardless of the initial constraint level in terms of anterior translation SSD.

Graft Intra-Articular Remodeling and Bone Incorporation in ACL Reconstruction: The State of the Art and Clinical Implications

The knee is one of the most frequently affected joints in sports trauma, and anterior cruciate ligament (ACL) injury and meniscal tears are the most common lesions. ACL reconstruction (ACLR) remains the treatment of choice for patients willing to return to their previous activity. There are different surgical techniques and different possible usable grafts. The graft used for ACLR surgery undergoes a bone incorporation process and an intra-articular remodelling named ligamentization until it reaches characteristics similar to the native ligament. After the first incorporation stage, the remodelling process is divided into an early stage that could last 4 weeks, a proliferative stage that lasts 4 to 12 weeks, and a final stage of ligamentization that could last over 1 year. The period of return to sport (RTS) after ACLR, which is becoming shorter and shorter, can be a high-risk period for athletes due to the risk of graft failure. This systematic review aims to define the phases of the ligamentization process considering graft type and fixation techniques, as well as the graft's anatomopathological and biomechanical characteristics, to evaluate a criterion-based rehab progression and maximize patient outcomes for an RTS respecting graft biology. The rehabilitative program has to promote and optimize the graft remodelling and incorporation processes; moreover, it has to accommodate physiological graft healing and avoid overloading. An early RTS and noncompliance with the biological characteristics of the graft in the various phases are associated with a high incidence of re-injury.

Effectiveness of Platelet-Rich Plasma in Anterior Cruciate Ligament Reconstruction: A Systematic Review of Randomized Controlled Trials

This study aimed to identify the effectiveness of platelet-rich plasma (PRP) for patients operated with anterior cruciate ligament reconstruction (ACLR). Databases of PubMed, Embase, and CENTRAL were independently retrieved by two authors, for identifying the eligible randomized controlled trials (RCTs) comparing the clinical and imaging outcomes of ACL reconstructed patients augmented with or without PRP. The Cochrane Collaboration tool was utilized to assess the risk of bias of the included trials. We qualitatively synthesized the outcomes include the image evaluations on the healing of bone tunnels, graft remodeling, donor site healing and tunnel widening, and clinical evaluations on knee stability and function, pain symptom by visual analogue scale (VAS), inflammatory parameters and so on. A total of 16 RCTs, including 1025 patients, were included for eligibility. Generally, the included studies were of low risk of bias, but the conducting of allocation concealment was not clearly described in many studies. Three imaging techniques, including MRI, CT and ultrasound, were selected in these trials. Significant improvement on graft remodeling, bone tunnel healing, harvest site healing and bone tunnel diameters were demonstrated in one of five (20.0%), three of five (60.0%), two of four (50.0%) and one of five (20.0%) studies respectively, for PRP group. Various clinical outcomes, such as IKDC score, Lysholm score, Tegner score, knee anteroposterior and rotational laxity, range of motion and VAS, could not be improved with PRP application. The PRP is associated with very limited role in improving knee outcomes following ACLR, and there is no indication for PRP procedures in ACLR at this stage.

Cross-sectional study on relationships between physical function and psychological readiness to return to sport after anterior cruciate ligament reconstruction

BACKGROUND

Information about specific factors of physical function that contribute to psychological readiness is needed to plan rehabilitation for a return to sports. The purpose of this study was to identify specific physical functions related to the psychological readiness of patients aiming to return to sports 6 months after reconstruction. We hypothesized that the knee strength is a factor related to the Anterior Cruciate Ligament-Return to Sport after Injury scale (ACL-RSI) cutoff score for a return to sports.

METHODS

This was a cross-sectional study. Fifty-four patients who had undergone primary reconstruction using hamstring tendon participated in this study. Psychological readiness was measured using the ACL-RSI in patients at 6 months after reconstruction. To identify specific physical functions related to the ACL-RSI score, participants were divided into groups with ACL-RSI scores of ≥ 60 or < 60. Non-paired t-tests or the Mann-Whitney test were performed to analyze group differences in objective variables in physical function: (1) knee strength in both legs; (2) leg anterior reach distance on both sides; and (3) single-leg hop (SLH) distances in three directions for both legs.

RESULTS

Significant differences between groups were identified in knee flexion strength (60°/s) for the uninvolved limb, hamstring-to-quadriceps ratio (60°/s) for the uninvolved limb, knee flexion strength (180°/s) for the involved limb, limb symmetry index (LSI) of leg anterior reach distance, the ratio of the distance to the height of the patient and LSI of SLH distances in lateral and medial directions.

CONCLUSION

This study revealed that at 6 months after reconstruction, increased knee flexion strength (ratio of peak torque measured to body mass of the patient), hamstring-to-quadriceps ratio, leg anterior reach distance LSI, and lateral and medial SLH appear important to exceed the ACL-RSI cutoff for a return to sports. The present results may be useful for planning post-operative rehabilitation for long-term return to sports after reconstruction.

Efficacy of Stem Cell Therapy for Tendon Graft Ligamentization After Anterior Cruciate Ligament Reconstruction: A Systematic Review

Background

Sufficient intra-articular graft ligamentization enhances the biomechanical and biological properties of the femur-graft-tibia complex to ensure knee stability after anterior cruciate ligament (ACL) reconstruction using a tendon graft. It remains unclear whether stem cell therapy promotes tendon graft ligamentization.

Purpose/Hypothesis

The purpose of this study was to compare tendon graft ligamentization after primary ACL reconstruction with versus without stem cell therapy. It was hypothesized was that stem cell therapy would promote tendon graft ligamentization by enhancing the biomechanical and histological properties of the tendon graft after ACL reconstruction.

Study Design

Systematic review.

Methods

A systematic review was performed according to the guidelines outlined in the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement to identify controlled animal studies that compared tendon graft ligamentization outcomes after primary ACL reconstruction in groups with and without stem cell therapy. Biomechanical and histological outcomes were assessed.

Results

A total of 4 studies met the eligibility criteria and were included in this review. Bone marrow-derived mesenchymal stem cells were used in 3 studies, while tendon-derived stem cells were used in 1 study. An intra-articular injection was used to deliver conditioned medium and stem cells in 2 studies, while around-graft application was used to deliver bone marrow-derived mesenchymal stem cells in 2 studies. Stem cell therapy enhanced the biomechanical and histological properties of the tendon graft after ACL reconstruction.

Conclusion

This review revealed that stem cell therapy is a promising technique that promotes graft ligamentization by enhancing the biomechanical and histological properties of the tendon graft after ACL reconstruction in animal models. There is a need for future preclinical studies aimed at evaluating the effect of stem cells on graft ligamentization and identifying the optimal method of intra-articular stem cell delivery.

Early Return to Play After Anterior Cruciate Ligament Reconstruction: Is It Worth the Risk?

Objective

To compare the outcomes of a 6-month-long accelerated rehabilitation with a 12-month-long rehabilitation. There is no consensus on the optimal duration of rehabilitation after anterior cruciate ligament reconstruction (ACLR). Trends in the past decades have shifted towards accelerated programs, often resulting in a return to play (RTP) at 4–6 months, postoperatively. However, longer rehabilitation cycles have recently experienced renaissance due to a greater understanding of graft remodeling.

Methods

Adult athletes who underwent ACLR between 2015 and 2018 by the same surgeon were included and followed-up prospectively for 24 months. Participants were allocated into two groups based on their RTP (6 months vs. 12 months) and compared with graft elongation, reoperation rate, and sports career (quit or continue) outcomes.

Results

Fifty-four patients underwent accelerated rehabilitation and 92 completed conventional rehabilitation. The accelerated rehabilitation was significantly associated with graft elongation—the accelerated rehabilitation group (n=9) and the conventional rehabilitation group (n=0), p<0.001—and need for reoperation—the accelerated rehabilitation group (n=5) and the conventional rehabilitation group (n=1), p=0.026. Although the relationship between rehabilitation time and quitting competitive sports did not reach significance at 0.05 level (p=0.063), it was significant when p<0.1, thereby showing a clear trend.

Conclusion

Accelerated rehabilitation increased graft elongation risk. Knee laxity ≥3 mm measured at 6 months after ACLR should be accompanied by RTP time frame re-evaluation. Arthrometry checkups or routine magnetic resonance imaging shortly after RTP may be considered in cases of accelerated rehabilitation.

Clinical and radiological comparison of bioactive glass and poly-L-lactic acid/hydroxyapatite bioabsorbable interference screws for tibial graft fixation in anterior cruciate ligament reconstruction

BACKGROUND

Ligament reconstruction is still the main treatment modality for patients with a complete ligament rupture. The semitendinosus tendon, alone quadrupled or double folded and combined with the gracilis tendon, is still the most frequently used autologous graft for a reconstructive procedure. Absorbable interference screw usage has gained popularity in the past decade because they create less artifacts during MR imaging and tend to osteointegrate over the years, arguably leading to a more anatomic fixation. The purpose of this study was to compare the 5-year radiological and clinical results of two different tibial graft fixation screws.

HYPOTHESIS

We hypothesized that bioabsorbable interference screws made of bioactive glass would lead to higher rates of osteointegration, better overall clinical results, less foreign body reaction rates and less tibial tunnel widening when compared to the poly-L-lactic acid/hydroxyapatite (PLLA-HA) screws.

PATIENTS AND METHODS

Fifty-one patients treated with an anatomic single bundle ACL reconstruction between June 2015 and July 2016 at our institution were included in the study. The tibial graft was fixed with a bioactive glass screw in 24, and with a PLLA-HA in 27 patients. Tibial tunnel widening, foreign body reaction, osteointegration and resorption rates were evaluated and compared on a magnetic resonance scan at a minimum of 5 year postoperatively. Overall clinical results and side-to-side difference on KT-1000 were also analyzed in-between groups.

RESULTS

Tibial tunnel widening was similar for both groups. Foreign body reaction, while not statistically significant, was less aggressive when bioactive glass screws were used. Osteointegration and resorption rates of the bioactive glass screws were significantly higher than the PLLA-HA group (p=0.000). While all patients showed an overall improvement on postoperative scores (p=0.000), patients with a bioactive glass interference screw had statistically higher translational stability with KT-1000, compared to the poly-L-lactic acid/hydroxyapatite group (p=0.001).

DISCUSSION

At a minimum of 5 years, compared to conventional PLLA-HA interference screws, 45S5 bioactive glass screw provide higher resorption rates, are more highly biodegradable and provide overall good clinical results.

LEVEL OF EVIDENCE

III.

Minimizing the risk of graft failure after anterior cruciate ligament reconstruction in athletes. A narrative review of the current evidence

Anterior cruciate ligament (ACL) tear is one of the most common sport-related injuries and the request for ACL reconstructions is increasing nowadays. Unfortunately, ACL graft failures are reported in up to 34.2% in athletes, representing a traumatic and career-threatening event. It can be convenient to understand the various risk factors for ACL failure, in order to properly inform the patients about the expected outcomes and to minimize the chance of poor results. In literature, a multitude of studies have been performed on the failure risks after ACL reconstruction, but the huge amount of data may generate much confusion.The aim of this review is to resume the data collected from literature on the risk of graft failure after ACL reconstruction in athletes, focusing on the following three key points: individuate the predisposing factors to ACL reconstruction failure, analyze surgical aspects which may have significant impact on outcomes, highlight the current criteria regarding safe return to sport after ACL reconstruction.

Prospective Comparison of Functional and Radiological Outcomes of Arthroscopic Anterior Cruciate Ligament Reconstruction by Hamstring Graft Alone and Platelet-Rich Plasma Added to the Hamstring Graft

Aims and objectives: To measure the additional effect of platelet-rich plasma (PRP) on functional outcome of anterior cruciate ligament tear managed by augmenting anterior cruciate ligament (ACL) reconstruction with PRP.

Methods: The present study was conducted on patients with ACL tear admitted in the department of orthopaedics, King George’s Medical University, Lucknow wherein a total of 70 subjects were assigned into two groups of 35 patients each randomly, viz Group 1 in which the patients were treated by quadruple hamstring graft alone and Group 2 in which the patients were treated with augmented hamstring graft with PRP. The standardized anterior drawer test, Lachman’s test, Lysholm knee score were quantified both preoperatively and postoperatively at different follow-ups and also tibial tunnel widening was measured postoperatively at different follow-ups.

Result: The present study had 70 patients with ACL tears. The mean age of patients in non-PRP groups was 29.71 ±2.99 years while that in the PRP group was 28.34±4.32 years. On comparing the improvement in grades at pre-op, immediate postop, 6 weeks, and 3 months follow-ups, there was no statistically significant difference between the two groups. The tibial tunnel widening also showed no significant difference between the two groups.

Conclusion: In our study, it was found that both the groups showed improvements in grades of anterior drawer test and Lachman’s test postoperatively but the difference between both the groups was not significant. Similarly, while comparing the improvements in Lysholm knee score and tibial tunnel widening among both the groups, the difference was not significant. Follow up of 3 months was a limiting factor in our study. This technique needs further clinical evaluation to assess the long-term results.

Tackling the Challenges of Graft Healing After Anterior Cruciate Ligament Reconstruction-Thinking From the Endpoint

Anterior cruciate ligament (ACL) tear is common in sports and accidents, and accounts for over 50% of all knee injuries. ACL reconstruction (ACLR) is commonly indicated to restore the knee stability, prevent anterior–posterior translation, and reduce the risk of developing post-traumatic osteoarthritis. However, the outcome of biological graft healing is not satisfactory with graft failure after ACLR. Tendon graft-to-bone tunnel healing and graft mid-substance remodeling are two key challenges of biological graft healing after ACLR. Mounting evidence supports excessive inflammation due to ACL injury and ACLR, and tendon graft-to-bone tunnel motion negatively influences these two key processes. To tackle the problem of biological graft healing, we believe that an inductive approach should be adopted, starting from the endpoint that we expected after ACLR, even though the results may not be achievable at present, followed by developing clinically practical strategies to achieve this ultimate goal. We believe that mineralization of tunnel graft and ligamentization of graft mid-substance to restore the ultrastructure and anatomy of the original ACL are the ultimate targets of ACLR. Hence, strategies that are osteoinductive, angiogenic, or anti-inflammatory should drive graft healing toward the targets. This paper reviews pre-clinical and clinical literature supporting this claim and the role of inflammation in negatively influencing graft healing. The practical considerations when developing a biological therapy to promote ACLR for future clinical translation are also discussed.

Long-term evaluation of pediatric ACL reconstruction: high risk of further surgery but a restrictive postoperative management was related to a lower revision rate

INTRODUCTION

The guidelines regarding rehabilitation after pediatric anterior cruciate ligament reconstruction (ACLR) are sparse. The aim of the study was to retrospectively describe the long-term outcome regarding further surgery and with special emphasis on the revision rate after two different postoperative rehabilitation programs following pediatric ACLR.

MATERIAL AND METHODS

193 consecutive patients < 15 years of age who had undergone ACLR at two centers, A (n = 116) and B (n = 77), in 2006-2010 were identified. Postoperative rehabilitation protocol at A: a brace locked in 30° of flexion with partial weight bearing for 3 weeks followed by another 3 weeks in the brace with limited range of motion 10°-90° and full weight bearing; return to sports after a minimum of 9 months. B: immediate free range of motion and weight bearing as tolerated; return to sports after a minimum of 6 months. The mean follow-up time was 6.9 (range 5-9) years. The mean age at ACLR was 13.2 years (range 7-14) years. The primary outcome measurement in the statistical analysis was the occurrence of revision. Multivariable logistic regression analysis was performed to investigate five potential risk factors: surgical center, sex, age at ACLR, time from injury to ACLR and graft diameter.

RESULTS

Thirty-three percent had further surgery in the operated knee including a revision rate of 12%. Twelve percent underwent ACLR in the contralateral knee. The only significant variable in the statistical analysis according to the multivariable logistic regression analysis was surgical center (p = 0.019). Eight percent of the patients at center A and 19% of the patients at B underwent ACL revision.

CONCLUSIONS

Further surgery in the operated knee could be expected in one third of the cases including a revision rate of 12%. The study also disclosed a similar rate of contralateral ACLR at 12%. The revision rate following pediatric ACLR was lower in a center which applied a more restrictive rehabilitation protocol.

LEVEL OF EVIDENCE

Case-control study, Level III.

Application and Surgical Technique of ACL Reconstruction Using Worldwide Registry Datasets: What Can We Extract?

Anterior cruciate ligament (ACL) injuries are among the most common knee injuries. The purpose of this study was to compare surgical reconstruction of the ACL between different countries and regions in order to describe differences regarding epidemiological data, reconstruction frequency, and graft choice. A systematic literature search was performed using the ACL study group website in order to identify the relevant knee ligament registers. Four national registries were included, comprising those from Sweden, the UK, New Zealand, and Norway. A large variation was found concerning the total number of primary ACL reconstructions with a reported range from 4.1 to 51.3 per 100,000 inhabitants. The country-specific delay between injury and reconstruction varied between an average of 6.0 months and 17.6 months. The leading sports activities resulting in ACL injury included soccer, alpine skiing, handball, rugby, and netball. Moreover, a strong variability in graft choice for primary reconstruction was found. The comparison of ACL registers revealed large differences, indicating different clinical implications regarding conservative or surgical therapy and choice of the preferable graft. ACL registers offer a real-world clinical perspective with the aim to improve quality and patient safety by investigating factors associated with subsequent surgical outcomes.

Differential MMP 1 and MMP 13 expression in proliferation and ligamentization phases of graft remodeling in anterior cruciate ligament reconstruction

Purpose: Graft remodeling in anterior cruciate ligament reconstruction (ACLR) demonstrates three distinct phases: necrosis, proliferation and ligamentization. Biological enhancement involves modulating these processes, but the cellular activities related to extracellular matrix remodeling have not been investigated. We hypothesized that changes in matrix metalloproteinases (MMPs) 1 and 13 expression are involved in the transition of proliferation phase to ligamentization phase of graft remodeling.Materials and methods: Thirty-three rats underwent ACLR. Tendon grafts were harvested at week 1 (necrosis), 2 (proliferation), or 12 (ligamentization) post-operation for histological examination (n = 3), or for isolation of graft-derived cells (n = 8) for flow cytometry, proliferation assay, cell invasion assay, measurement of gene expression related to matrix remodeling (Col1A1, Col3A1, MMP1, tissue inhibitor of marix metalloproteinase 1 (TIMP1), and MMP13) and total MMP activities.Results: Increased cellularity in tendon graft was contributed by active cell proliferation and migration at week 2 post-operation, while decreased cellularity were paralleled by increased apoptosis at week 12. All genes measured (Col1A1, Col3A1, MMP1, TIMP1, and MMP13) increased significantly in week 2 cells compared to week 1 cells. MMP1 expression subsided at week 12, while MMP13 expression kept increasing till 12 weeks post-operation. Total MMP activities was 3-fold higher in cultured graft-derived cells from week 2 as compared to cells from week 12. Two distinct processes of graft remodeling were identified, characterized by increased MMP1 expression with cell proliferation and increased MMP13 expression with cell apoptosis.Conclusions: Unfavorable matrix remodeling during the proliferation phase is found with increased MMP1, while remodeling leading to ligamentization is associated with increased MMP13 expression.

Post-ACL Reconstruction Graft Failure in Severe Gout Arthritis Patient

Introduction

Pain and instability following an anterior cruciate ligament (ACL) reconstruction remain a significant issue. Common causes include infection and inflammation, and mechanical issues such as graft failure.

Case Presentation

A 36-year-old male with an ACL reconstruction six years prior was admitted due to pain and swelling. The ACL graft that had ruptured was found arthroscopically. Numerous gout crystals and tophus were observed inside. This finding is suggested as a cause of this kind of complication.

Discussion

Biological failure is one of the causes of graft failure. Gout arthritis is associated with internal derangement of the joint structures, which is reported in advanced case.

Conclusion

Severe gouty arthritis, even though rare, could be an etiology of graft failure following ACL reconstruction and cause significant morbidity.

Arthroscopic Reconstruction of the Posterior Cruciate Ligament with a Ligament-advanced Reinforcement System and Hamstring Tendon Autograft: A Retrospective Study

OBJECTIVE

Both ligament-advanced reinforcement system (LARS) and hamstring tendon autograft can serve as grafts for posterior cruciate ligament (PCL) reconstruction. However, few studies have compared the effectiveness of these two approaches. This study therefore aimed to compare the clinical efficacy of arthroscopic reconstruction of the PCL using either the LARS or hamstring tendon autograft.

METHODS

A total of 36 patients who underwent PCL reconstruction were retrospectively analyzed. Within this cohort, 15 patients received a reconstruction using the LARS (LARS group) and 21 using the hamstring tendon autograft (HT group).

RESULTS

The pre- and post-operative subjective scores and knee stability were evaluated and the patients were followed up for a period of 2 to 10.5 years (4.11±2.0 years on average). The last follow-up showed that functional scores and knee stability were significantly improved in both groups (P<0.05). Six months after operation, Lysholm scores and IKDC subjective scores were higher in the LARS group than in the HT group (P<0.05). Nonetheless, the last follow-up showed no significant differences in the functional scores or the posterior drawer test between the two groups (P>0.05). In the LARS and HT groups, 12 and 9 patients, respectively exhibited KT1000 values <3 mm, with the difference being statistically significant (P<0.05). In the HT group, the diameter of the four-strand hamstring tendon was positively correlated with height (P<0.05), which was 7.37±0.52 mm in males and 6.50±0.77 mm in females (P<0.05).

CONCLUSION

Both LARS and hamstring tendon approaches achieved good efficacy for PCL reconstruction, but patients in the LARS group exhibited faster functional recovery and better knee stability in the long term. LARS is especially suitable for those who hope to resume activities as early as possible.

Effects of and Response to Mechanical Loading on the Knee

Mechanical loading to the knee joint results in a differential response based on the local capacity of the tissues (ligament, tendon, meniscus, cartilage, and bone) and how those tissues subsequently adapt to that load at the molecular and cellular level. Participation in cutting, pivoting, and jumping sports predisposes the knee to the risk of injury. In this narrative review, we describe different mechanisms of loading that can result in excessive loads to the knee, leading to ligamentous, musculotendinous, meniscal, and chondral injuries or maladaptations. Following injury (or surgery) to structures around the knee, the primary goal of rehabilitation is to maximize the patient's response to exercise at the current level of function, while minimizing the risk of re-injury to the healing tissue. Clinicians should have a clear understanding of the specific injured tissue(s), and rehabilitation should be driven by knowledge of tissue-healing constraints, knee complex and lower extremity biomechanics, neuromuscular physiology, task-specific activities involving weight-bearing and non-weight-bearing conditions, and training principles. We provide a practical application for prescribing loading progressions of exercises, functional activities, and mobility tasks based on their mechanical load profile to knee-specific structures during the rehabilitation process. Various loading interventions can be used by clinicians to produce physical stress to address body function, physical impairments, activity limitations, and participation restrictions. By modifying the mechanical load elements, clinicians can alter the tissue adaptations, facilitate motor learning, and resolve corresponding physical impairments. Providing different loads that create variable tensile, compressive, and shear deformation on the tissue through mechanotransduction and specificity can promote the appropriate stress adaptations to increase tissue capacity and injury tolerance. Tools for monitoring rehabilitation training loads to the knee are proposed to assess the reactivity of the knee joint to mechanical loading to monitor excessive mechanical loads and facilitate optimal rehabilitation.

Application of Stem Cell Therapy for ACL Graft Regeneration

Graft regeneration after anterior cruciate ligament (ACL) reconstruction surgery is a complex three-stage process, which usually takes a long duration and often results in fibrous scar tissue formation that exerts a detrimental impact on the patients' prognosis. Hence, as a regeneration technique, stem cell transplantation has attracted increasing attention. Several different stem cell types have been utilized in animal experiments, and almost all of these have shown good capacity in improving tendon-bone regeneration. Various differentiation inducers have been widely applied together with stem cells to enhance specific lineage differentiation, such as recombinant gene transfection, growth factors, and biomaterials. Among the various different types of stem cells, bone marrow-derived mesenchymal stem cells (BMSCs) have been investigated the most, while ligament stem progenitor cells (LDSCs) have demonstrated the best potential in generating tendon/ligament lineage cells. In the clinic, 4 relevant completed trials have been reported, but only one trial with BMSCs showed improved outcomes, while 5 relevant trials are still in progress. This review describes the process of ACL graft regeneration after implantation and summarizes the current application of stem cells from bench to bedside, as well as discusses future perspectives in this field.

The efficacy of platelet rich plasma on anterior cruciate ligament reconstruction: a systematic review and meta-analysis

Anterior cruciate ligament (ACL) rupture is a common musculoskeletal injury, most frequently affecting young and physically active patients. Platelet-rich plasma (PRP) has been widely used in ACL reconstruction to augment the graft healing. However, high-level studies addressing its clinical efficacy could not reach a consensus. In this study, we assess the efficacy of PRP on pain relief, functional improvement along with radiological changes in patients who underwent ACL reconstruction. We performed comprehensive literature search and included 17 RCTs containing 970 participants who underwent ACL reconstruction. The combined data showed significant difference between PRP and control with regard to VAS score (MD: -1.12, 95% CI -1.92, -0.31; P = .007), subjective IKDC score (MD: 6.08, 95% CI 4.39, 7.77; P < .00001) and Lysholm score (MD: 8.49, 95% CI 1.63, 15.36; P = .02) by postoperative 6 months, but only pain reduction was deemed clinically important. At the end of one year's follow-up, no clinically meaningful improvement in VAS (MD: -0.47, P = .04), subjective IKDC score (MD: 3.99, P = .03), Lysholm score (MD: 2.30, P = .32), objective IKDC score (RR: 1.03, P = .09) and knee joint laxity (MD: 0.17, P = .28) was seen. In terms of radiological findings, about one-third of the studies favored PRP to facilitate the graft healing, improve the harvest site morbidity and prevent tunnel widening. In summary, moderate quality of evidence suggested that PRP could provide short-term but not long-term clinically important pain reduction.

Correlations between isokinetic knee torques and single-leg hop distances in three directions in patients after ACL reconstruction

Background

When planning rehabilitation and conditioning for performance enhancement and a return to sports after anterior cruciate ligament reconstruction, identifying the elements of physical function associated with single-leg hop is important. The purpose of this study was to clarify the relationship between single-leg hop distances in three directions and knee extensor and flexor strengths at 6 months after reconstruction.

Methods

Participants were 47 patients taking part in training sessions for sports involving cutting, pivoting, and jump-landing 6 months after reconstruction using a hamstring tendon. Single-leg hop distances in 3 directions (anterior, lateral, and medial) and isokinetic concentric strengths of knee extension and flexion were assessed at an angular velocity of 60°/s and 180°/s. Simple regression analyses using Spearman’s rank correlation coefficient were performed to assess relationships between single-leg hop distances and knee strengths.

Results

In the involved limb, correlations between single-leg hop distances in 3 directions and knee strengths were significant (P < 0.01) and correlation coefficients ranged from 0.48 to 0.65. Correlation coefficients between all single-leg hop parameters and knee extension/flexion strengths at an angular velocity of 180°/s were greater than those of 60°/s.

Conclusions

In this cross-sectional study of patients who participated in sports training sessions that required jump-landings and cutting approximately 6 months after reconstruction using hamstring grafts, isokinetic knee flexor, and extensor torques were moderately to strongly associated with single-leg hop distances in lateral, medial, and anterior directions. Given these relationships, assessments and exercises for knee strength and single-leg hop distances should be planned.

Histomorphological Alterations of Human Anterior Cruciate Ligament Grafts During Mid-Term and Long-Term Remodeling

Objective

The aim of the present paper is to analyze mid‐term and long‐term alterations of human anterior cruciate ligament (ACL) grafts during the remodeling process with special regards to cellularity, α‐smooth muscle protein (αSMP) expression, and crimp length in comparison to the native ACL.

Methods

A total of 34 patients were included (23 male and 11 female). Biopsies of 13 semitendinosus tendon and 14 patellar tendon autografts were obtained during surgical revision secondary to an ACL reconstruction. According to the interval between the index procedure and sample collection, the patients were divided into four groups: 4–12 months, 13–60 months, 61–108 months, and >108 months. Seven samples of native ruptured ACL tissue obtained during surgical intervention served as control. All biopsies were taken from the intraligamentous part of the ACL or the graft. Histomorphological and immunohistochemical analyses were conducted after samples were stained using hematoxylin–eosin, Giemsa, and αSMP enzyme‐labeled antibodies. The total cell density, the numbers of fibroblasts and fibrocytes, the fibroblast/fibrocyte ratio, the number of αSMP+ cell nuclei, and the percentage of αSMP+ cells per fibroblast as well as the crimp lengths were determined using light microscopy.

Results

In the early phase of remodeling, the grafts featured extensively high total cell counts (1021.2 ± 327.8, P = 0.001), with high numbers of fibroblasts (841.4 ± 245.2, P = 0.002), fibrocytes (174.5 ± 113.0, P = 0.04), and αSMP+ cells (78.3 ± 95.0, P = 0.02) compared to controls (390.1 ± 141.7, 304.5 ± 160.8, 65.6 ± 31.4 and 2.3 ± 2.6, respectively). Thereafter, the numbers of all cell entities decreased. After more than 108 months, the percentage of αSMP+ cells per fibroblast reached physiological values (ratio 1.3 ± 1.0, P = 0.41; control 0.8 ± 0.8), while the total cell count (834.3 ± 183.7, P = 0.001) as well as the numbers of fibroblasts (663.5 ± 192.6, P = 0.006) and fibrocytes (134.1 ± 73.0, P = 0.049) remained significantly high. The fibroblast/fibrocyte ratio showed no significant alterations over the course of time compared to the controls. The collagen crimp lengths were elongated by tendency in the early phase (28.8 ± 12.9 mm, P = 0.15; control 20.7 ± 2.2 mm) and significantly shortened over time, with the lowest values in the long term (14.8 ± 2.0 mm, P = 0.001). The comparison of biopsies from semitendinosus tendon and patellar tendon autografts revealed no significant differences for any of the histomorphological parameters investigated.

Conclusion

This study reveals distinctive mid‐term and long‐term immunomorphological alterations during human ACL graft remodeling. These data clearly indicate that the remodeling is a process that continues for 9 years or more. Furthermore, it seems to be a process of adaptation rather than full restoration. Even in the long run, several biological properties of the native ACL are not completely reestablished.

ACL Growth With Age in Pediatric Patients: An MRI Study

BACKGROUND

There is limited knowledge of morphologic changes of the anterior cruciate ligament (ACL) during childhood. The purpose of the study is to describe normal ACL growth in pediatric patients.

METHODS

We performed retrospective review of patients under 19 years of age with at least 2 serial magnetic resonance imaging (MRI) examinations of the same knee without ACL tear. The parameters measured included length of the ACL, width of the ACL in sagittal and coronal planes, physeal status, ACL-tibial inclination angle, Notch Width Index, ACL tibial attachment width and midpoint, and anterior to posterior length and height of the tibial epiphysis. Pearson correlation coefficients were calculated to determine the strength of correlation of each parameter relative to age. Growth curves were calculated for individual parameters, producing a predictive model for growth of the ACL over time.

RESULTS

One hundred forty-seven patients (365 MRIs) were included. The average age at initial MRI was 12.2 years (range: 1.2 to 18.4 y). The Pearson correlation coefficient for each parameter was statistically significant relative to age. Younger patients had more oblique, anteriorly attached ACLs. Three distinct phases of growth were observed: patients age 1.5 to 5.75 years average 2.25 mm of growth per year; patients aged 6 to 11.5 average 1.46 mm of growth per year; growth slows at age 11.75, stopping by 18.5 years. The growth model for ACL sagittal width increased 0.45 mm/y from age 1.5 to 14.5 after which it plateaus, whereas coronal width increased 0.22 mm/y from age 1.5 to 18.75.

CONCLUSIONS

In the pediatric patient, the ACL grows in length and width in a predictable manner until age 18. This model aids clinicians in predicting normal ACL parameters for anatomic reconstruction procedures in the skeletally immature patient.

LEVEL OF EVIDENCE

Level IV.

Assessment of Graft Maturity After Anterior Cruciate Ligament Reconstruction Using Autografts: A Systematic Review of Biopsy and Magnetic Resonance Imaging studies

Purpose

The purpose of this investigation was to evaluate systematically the literature concerning biopsy, MRI signal to noise quotient (SNQ) and clinical outcomes in graft-maturity assessment after autograft anterior cruciate ligament reconstruction (ACLR) and their possible relationships.

Methods

The systematic review was reported and conducted according to the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. Studies through May 2019 evaluating methods of intra-articular ACL autograft maturity assessment were considered for inclusion. Eligible methods were histologic studies of biopsy specimens and conventional MRI studies reporting serial SNQ and/or correlation with clinical parameters.

Results

Ten biopsy studies and 13 imaging studies, with a total of 706 patients, met the inclusion criteria. Biopsy studies show that graft remodeling undergoes an early healing phase, a phase of remodeling or proliferation and a ligamentization phase as an ongoing process even 1 year after surgery. Imaging studies showed an initial increase in SNQ, peaking at approximately 6 months, followed by a gradual decrease over time. There is no evident correlation between graft SNQ and knee stability outcome scores at the short- and long-term follow-up after ACLR.

Conclusions

The remodeling of the graft is an ongoing process even 1 year after ACLR, based on human biopsy studies. MRI SNQ peaked at approximately 6 months, followed by a gradual decrease over time. Heterogeneity of the MRI methods and technical restrictions used in the current literature limit prediction of graft maturity and clinical and functional outcome measures by means of MRI graft SNQ after ACLR.

Level of evidence

Level IV, systematic review, including level III and IV studies.

Identifying potential patient-specific predictors for anterior cruciate ligament reconstruction outcome - a diagnostic in vitro tissue remodeling platform

Purpose

Upon anterior cruciate ligament (ACL) rupture, reconstruction is often required, with the hamstring tendon autograft as most widely used treatment. Post-operative autograft remodeling enhances graft rupture risk, which occurs in up to 10% of the patient population, increasing up to 30% of patients aged under 20 years. Therefore, this research aimed to identify potential biological predictors for graft rupture, derived from patient-specific tissue remodeling-related cell properties in an in vitro micro-tissue platform.

Methods

Hamstring tendon-derived cells were obtained from remnant autograft tissue after ACL reconstructions (36 patients, aged 12–55 years), and seeded in collagen I gels on a micro-tissue platform. Micro-tissue compaction over time – induced by altering the boundary constraints – was monitored. Pro-collagen I expression was assessed using ELISA, and protein expression of tenomodulin and α-smooth muscle actin were measured using Western blot. Expression and activity of matrix metalloproteinase 2 were determined using gelatin zymography.

Results

Only micro-tissues corresponding to younger patients occasionally released themselves from the constraining posts. Pro-collagen I expression was significantly higher in younger patients. Differences in α-smooth muscle actin and tenomodulin expression between patients were found, but these were age-independent. Active matrix metalloproteinase 2 expression was slightly more abundant in younger patients.

Conclusions

The presented micro-tissue platform exposed patient-specific remodeling-related differences between tendon-derived cells, with the micro-tissues that released from constraining posts and pro-collagen I expression best reflecting the clinical age-dependency of graft rupture. These properties can be the starting point in the quest for potential predictors for identifying individual patients at risk for graft rupture.

Enhancement of tendon-bone interface healing and graft maturation with cylindrical titanium-web (TW) in a miniature swine anterior cruciate ligament reconstruction model: histological and collagen-based analysis

Background

Tendon-bone interface healing and ligamentization of the graft in anterior cruciate ligament (ACL) reconstruction with autografts are important factors affecting treatment outcome. This study aimed to investigate the effectiveness of a cylindrical titanium-web (TW) in tendon-bone interface healing and graft maturation in ACL reconstruction.

Methods

Fourteen mature female CLAWN miniature swine underwent bilateral ACL reconstructions with patellar tendon (PT) autografts. In one limb, the TW/tendon complex was placed into the proximal side of the tibial tunnel. Only the graft was transplanted into the tunnel in the control limb. The proximal side of the graft was sutured into the stump of the native ACL and the distal end was stapled to the tibia. The animals were euthanized at 4 and 15 weeks postoperatively, for histological and biochemical analyses.

Results

Microscopic images in TW limbs showed that ingrowth of tendon-like tissue and mineralized bone tissue into the TW connected the bone and the tendon directly. In contrast, fibrous tissue intervened between the bone and tendon in the control limbs. The total amount of collagen cross-links (which defines the strength of collagen fibers) and the maturation of collagen cross-links in TW tendons were significantly higher (p < 0.05) than those of control limbs. There was no significant difference in the ratio of dihydroxy-lysinonorleucine to hydroxy-lysinonorleucine (an indicator of tissue specific collagen maturation) between TW tendons and that of the native PT.

Conclusions

TW promoted the maturation and formation of collagen cross-links in the grafted tendon while maintaining the cross-links pattern of native tendon collagen, and enabled direct binding of tendon to bone.

Autografts vs Synthetics for Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis

To describe the outcomes of autografts and synthetics in anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstruction with respect to instrumented laxity measurements, patient‐reported outcome scores, complications, and graft failure risk. We searched PubMed, Cochrane Library, and EMBASE for published randomized controlled trials (RCT) and case controlled trials (CCTs) to compare the outcomes of the autografts versus synthetics after cruciate ligament reconstruction. Data analyses were performed using Cochrane Collaboration RevMan 5.0. Nine studies were identified from the literature review. Of these studies, three studies compared the results of bone–patellar tendon–bone (BPTB) and ligament augmentation and reconstruction system (LARS), while six studies compared the results of four‐strand hamstring tendon graft (4SHG) and LARS. The comparative study showed no difference in Lysholm score and failure risk between autografts and synthetics. The combined results of the meta‐analysis indicated that there was a significantly lower rate of side‐to‐side difference > 3 mm (Odds Ratio [OR] 2.46, 95% confidence intervals [CI] 1.44–4.22, P = 0.001), overall IKDC (OR 0.40, 95% CI 0.19–0.83, P = 0.01), complications (OR 2.54, 95% CI 1.26–5.14, P = 0.009), and Tegner score (OR −0.31, 95% CI −0.52–0.10, P = 0.004) in the synthetics group than in the autografts group. This systematic review comparing long‐term outcomes after cruciate ligament reconstruction with either autograft or synthetics suggests no significant differences in failure risk. Autografts were inferior to synthetics with respect to restoring knee joint stability and patient‐reported outcome scores, and were also associated with more postoperative complications.

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.

Outcome Differences of Remnant- Preserving versus Non-Preserving Methods in Arthroscopic Anterior Cruciate Ligament Reconstruction: A Meta-analysis with Subgroup analysis

Purpose

To analyze differences in clinical outcomes of arthroscopic anterior cruciate ligament reconstruction between remnant-preserving and non-preserving methods.

Methods

International electronical databases PubMed, Embase, and the Cochrane central database from January 1966 to December 2017 were searched for randomized controlled trials (RCTs) and observational studies that compared differences of clinical outcomes of ACL reconstruction with and without remnant preservation. A meta-analysis of these studies was performed to compare clinical outcomes. Subgroup analyses were conducted to evaluate the role of methodological quality in primary meta-analysis estimates.

Results

Five RCTs and six observational studies were included in this meta-analysis and subgroup analysis. The remnant-preserving method in arthroscopic ACL reconstruction showed a statistically significant difference compared to the non-preserving method regarding arthrometric evaluation (side-to-side difference). Lachman test, Lysholm scores, and IKDC subjective scores showed statistically minor difference in meta-analysis, but showed no significant difference in subgroup analysis. Remained parameters including pivot shift test, IKDC grades, incidence of cyclops lesion showed no statistically differences in meta-analysis or subgroup analysis.

Conclusions

This meta-analysis with subgroup analysis showed that arthroscopic remnant-preserving ACL reconstruction provided statistically significant but limited clinical relevance in terms of arthrometric evaluation. Results of Lachman test, Lysholm scores, and IKDC subjective scores demonstrated statistically minor differences.

A multi-chamber tissue culture device for load-dependent parallel evaluation of tendon explants

Background

Injuries in the musculoskeletal system, such as tendon and ligament ruptures, are challenging to manage and often require surgical reconstructions with limited long-term success. Thus, characterizations of these tissues are urgently needed to better understand cellular mechanisms that regulate tissue homeostasis and healing. Explant culturing systems allow for ex vivo analysis of tissues in an environment that mimics the native microenvironment in vivo.

Methods

Collaborative efforts within our institution facilitated the establishment of a novel explant culturing system. Tissue specimens cultured in single wells, with individual applied loading and/or biological environment, allowed characterization of tissue cultured under a variety of biological loading conditions. Quantitative PCR analysis for selected gene markers was our primary outcome.

Results

Data were stratified for analysis by either culture environment or loading condition. Our gene expression results show that specimens clustered by culture condition may differ in molecular markers related to ECM production (e.g., Col1a1, Adamts4) and/or organization (e.g., Tnc, Dnc). In contrast, loading condition did significantly alter the median gene expression levels of tissues in comparison to unloaded control samples, although gene expression values related to ECM degradation (e.g., Mmp1, Mmp10) were altered in tendons cultured under tension in the device.

Conclusion

Our study demonstrates promising utility of a novel explant culturing system for further characterization of musculoskeletal tissues such as native tendons and ligaments, as well as pathologic fibrotic tissues resulting from arthrofibrosis or Dupuytren’s disease.

In vivo assessment of high-molecular-weight polyethylene core suture tape for intra-articular ligament reconstruction: an animal study

AIMS

Options for the treatment of intra-articular ligament injuries are limited, and insufficient ligament reconstruction can cause painful joint instability, loss of function, and progressive development of degenerative arthritis. This study aimed to assess the capability of a biologically enhanced matrix material for ligament reconstruction to withstand tensile forces within the joint and enhance ligament regeneration needed to regain joint function.

MATERIALS AND METHODS

A total of 18 New Zealand rabbits underwent bilateral anterior cruciate ligament reconstruction by autograft, FiberTape, or FiberTape-augmented autograft. Primary outcomes were biomechanical assessment (n = 17), microCT (µCT) assessment (n = 12), histological evaluation (n = 12), and quantitative polymerase chain reaction (qPCR) analysis (n = 6).

RESULTS

At eight weeks, FiberTape alone or FiberTape-augmented autograft demonstrated increased biomechanical stability compared with autograft regarding ultimate load to failure (p = 0.035), elongation (p = 0.006), and energy absorption (p = 0.022). FiberTape-grafted samples also demonstrated increased bone mineral density in the bone tunnel (p = 0.039). Histological evaluation showed integration of all grafts in the bone tunnels by new bone formation, and limited signs of inflammation overall. A lack of prolonged inflammation in all samples was confirmed by quantification of inflammation biomarkers. However, no regeneration of ligament-like tissue was observed along the suture tape materials. Except for one autograft failure, no adverse events were detected.

CONCLUSION

Our results indicate that FiberTape increases the biomechanical performance of intra-articular ligament reconstructions in a verified rabbit model at eight weeks. Within this period, FiberTape did not adversely affect bone tunnel healing or invoke a prolonged elevation in inflammation. Cite this article: Bone Joint J 2019;101-B:1238-1247.

Obesity and recovery of muscle strength after anterior cruciate ligament reconstruction in pediatric patients

PURPOSE:

To explore factors influencing muscle strength after anterior cruciate ligament (ACL) reconstruction (ACLR) in pediatric patients. We hypothesized that obesity/overweight, autograft hamstring tendon, and concomitant injuries would be associated with slower muscle recovery.

METHODS:

We retrospectively reviewed the records of pediatric ACLR patients during a 3-year period. Muscle recovery was defined as ≥85% of peak torque compared with the contralateral side. We categorized patients as either obese/overweight or normal weight. Statistical analysis was performed using Mann-Whitney U, analysis of variance, and χ² tests ( α level < 0.05).

RESULTS:

The study group consisted of 330 patients, of whom 198 (60%) and 231 (70%) met quadriceps and hamstring recovery criteria, respectively, at final testing (mean: 7.0 ± 3.2 months). Patients recovered hamstring and quadriceps strength at a mean of 5.3 ± 2.2 months and 6.1 ± 2.3 months, respectively. Hamstring muscle recovery took significantly longer in obese/overweight patients (mean: 5.7 ± 2.2 months) versus normal-weight patients (mean: 5.1 ± 2.1 months; p = 0.025), but quadriceps recovery did not (obese/overweight mean: 6.5 ± 2.6 months; normal-weight mean: 5.9 ± 2.1 months; p = 0.173).

CONCLUSION:

Concomitant injuries and graft type were not associated with length of time to recovery of muscle strength. Obesity/overweight was associated with delay in recovery of hamstring but not quadriceps strength.

[A correlation study between the Mohawk expression level and the collagen fiber diameter of hamstring tendon graft after anterior cruciate ligament reconstruction]

Objective

To evaluate the correlation between the Mohawk (MKX) expression level and the collagen fiber diameter of autologous hamstring tendon graft during the stable graft remodeling phase after anterior cruciate ligament (ACL) reconstruction.

Methods

Between January 2018 and August 2018, patients who underwent arth-roscopic single-bundle anatomical ACL reconstruction with autologous hamstring tendons for at least 48 months and also underwent second-look arthroscopy were enrolled in study. During the second-look arthroscopic procedures, ACL graft biopsies were performed from the surface of central part of the ligament. MKX expressions of ACL grafts were analysed by real-time fluorescent quantitative PCR (qRT-PCR). The ultrastructure of collagen fibers of grafts were evaluated by transmission electron microscopy, which included average diameter of collagen fibers (D _c), average diameter of large-diameter collagen fibers (D _L), average diameter of small-diameter collagen fibers (D _S), and large-small collagen fibers ratio (R _L/S). The correlation between MKX expression level and graft collagen fiber diameter was calculated.

Results

Twenty-six patients met the selection criteria and their ACL graft specimens were enrolled in the study. The interval between ACL reconstruction and second-look arthroscopy was 52-128 months, with an average of 78.6 months. Arthroscopic graft remodeling score was 3-6 (mean, 4.8). There were 17 cases of excellent remodeling and 9 cases of fair remodeling. All ACL grafts showed typical bimodal distributions of both large-diameter collagen fibers and small-diameter collagen fibers, but the ultrastructural characteristics of the graft collagen fibers were different according to different remodeling status under arthroscopy. The D _C, D _L, D _S, and R _L/S of the graft specimens were (65.2±9.3) nm, (91.6±10.5) nm, (45.7±8.6) nm, and 0.73±0.12, respectively. The relative expression level of MKX was 1.42±0.11, which was positively linearly correlated with D _C, D _L, and R _L/S, and the correlation coefficient was statistically significant ( r=0.809, P=0.000; r=0.861, P=0.000; r=0.942, P=0.000), while there was no significant correlation between D _S and relative expression level of MKX ( r=0.147, P=0.238). Regression analysis showed that the relative expression level of MKX could predict the D _C, D _L, and R _L/S results of the ACL graft specimens ( P<0.05).

Conclusion

After autologous hamstring tendon grafts stepped into stabilized remodeling phase, MKX expression level could predict the diameter measurement results of collagen fibers and be used as an important evaluation basis for graft collagen anabolic metabolism.

Change in Drop-Landing Mechanics Over 2 Years in Young Athletes After Anterior Cruciate Ligament Reconstruction

BACKGROUND

While between-limb landing asymmetries after anterior cruciate ligament reconstruction (ACLR) are linked with poor function and risk of additional injury, it is not currently understood how landing symmetry changes over time after ACLR.

PURPOSE/HYPOTHESIS

The purpose was to investigate how double-legged drop vertical jump (DVJ) landing and single-legged drop-landing symmetry changed from the time of return-to-sport (RTS) clearance to 2 years later in a prospective cohort of young athletes after ACLR. It was hypothesized that double-legged DVJ landing and single-legged drop-landing symmetry would improve from the time of RTS to 2 years later.

STUDY DESIGN

Descriptive laboratory study.

METHODS

The authors followed 64 young athletes with primary, unilateral ACLR for 2 years after RTS clearance. At the time of RTS and 2 years later, between-limb symmetry values for biomechanical variables of interest (VOIs) were calculated with 3-dimensional motion analysis during double-legged DVJ and single-legged drop-landing tasks. VOIs included knee flexion excursion, peak internal knee extension moment, peak vertical ground-reaction force, and peak trunk flexion (for single-legged task only). Symmetry values and proportions of participants meeting 90% symmetry cutoffs were compared between time points.

RESULTS

For double-legged DVJ landing, symmetry values for all VOIs and the proportions meeting 90% cutoffs for peak internal knee extension moment and peak vertical ground-reaction force were higher at 2 years after RTS as compared with RTS. For single-legged drop-landing, symmetry values were higher for knee flexion excursion and lower for peak trunk flexion at 2 years after RTS as compared with RTS, but the proportions meeting 90% cutoffs for all VOIs did not differ between time points.

CONCLUSION

Double-legged DVJ landing symmetry improved across VOIs over the 2 years after RTS following ACLR, while single-legged drop-landing did not improve as consistently. The implications of longitudinal landing asymmetry after ACLR should be further studied.

Tunnel placement in ACL reconstruction surgery: smaller inter-tunnel angles and higher peak forces at the femoral tunnel using anteromedial portal femoral drilling-a 3D and finite element analysis

PURPOSE

Recent studies have emphasized the importance of anatomical ACL reconstruction to restore normal knee kinematics and stability. Aim of this study is to evaluate and compare the ability of the anteromedial (AM) and transtibial (TT) techniques for ACL reconstruction to achieve anatomical placement of the femoral and tibial tunnel within the native ACL footprint and to determine forces within the graft during functional motion. As the AM technique is nowadays the technique of choice, the hypothesis is that there are significant differences in tunnel features, reaction forces and/or moments within the graft when compared to the TT technique.

METHODS

Twenty ACL-deficient patients were allocated to reconstruction surgery with one of both techniques. Postoperatively, all patients underwent a computed tomography scan (CT) allowing 3D reconstruction to analyze tunnel geometry and tunnel placement within the native ACL footprint. A patient-specific finite element analysis (FEA) was conducted to determine reaction forces and moments within the graft during antero-posterior translation and pivot-shift motion.

RESULTS

With significantly shorter femoral tunnels (p < 0.001) and a smaller inter-tunnel angle (p < 0.001), the AM technique places tunnels with less variance, close to the anatomical centre of the ACL footprints when compared to the TT technique. Using the latter, tibial tunnels were more medialised (p = 0.007) with a higher position of the femoral tunnels (p = 0.02). FEA showed the occurrence of higher, but non-significant, reaction forces in the graft, especially on the femoral side and lower, however, statistically not significant, reaction moments using the AM technique.

CONCLUSION

This study indicates important, technique-dependent differences in tunnel features with changes in reaction forces and moments within the graft.

LEVEL OF EVIDENCE

II.

Clinical experience with woven and parallel hamstring-tendon anterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to determine the effect of the weave technique for hamstring graft preparation on the diameter of the prepared graft, functional outcome, and need for harvesting of semitendinosus and gracilis (ST + G) or semitendinosus alone (ST).

MATERIALS AND METHODS

This retrospective study evaluated 340 patients who underwent arthroscopic anterior cruciate ligament (ACL) reconstruction from January 2013 to December 2015. Our protocol for graft preparation is that the graft length must be a minimum of 8 cm and the diameter must be between 7 and 10 mm. The parallel-graft preparation technique was used in 189 patient and the weave technique was used in 151 patients. Outcome was measured by using stress radiographs and International Knee Documentation Committee (IKDC) 2000 score.

RESULTS

In the parallel-graft preparation group, ST + G was used in 99 patients and ST was used in 90 patients. In the weave-graft preparation group, ST + G was used in 38 patients and ST alone was sufficient in 113 patients. The need for G harvest was less in the weave-technique group (p < 0.0001). There was no statistically significant difference at 2 years of follow-up in stress laxiometry, IKDC 2000 scores and rerupture rates between the two groups.

CONCLUSION

The weave technique helps to reduce the need for G harvest without compromising functional outcome. Level of evidence IV.

Early weight-bearing after anterior cruciate ligament reconstruction with hamstring grafts induce femoral bone tunnel enlargement: a prospective clinical and radiographic study

BACKGROUND

Bone tunnel enlargement following primary anterior cruciate ligament (ACL) reconstruction with soft tissue graft might be a severe disadvantage for revision surgery. The postoperative rehabilitation protocol including the non-weight-bearing periods were different depending on the surgeon or institute. To determine the relationship between femoral bone tunnel enlargement and the postoperative non-weight-bearing period after double-bundle ACL reconstruction with hamstring grafts.

METHODS

Forty-two patients who underwent primary double-bundle ACL reconstruction with hamstring grafts were divided into two postoperative non-weight-bearing protocol groups: 1-week non-weight-bearing postoperatively (group A, n = 19); and 2-week non-weight-bearing (group B, n = 18). Five cases were excluded due to additional knee injury, pregnancy, and lost to follow-up. Bone tunnel enlargement was evaluated by computed digital radiographs (anteroposterior (A-P) and lateral views) taken on the first postoperative day and at 12 months. Each tunnel diameter was shown as a percentage to the maximum joint width of the proximal tibia in the A-P view, or a percentage of the maximum diameter of the patella in the lateral view. To determine the incidence of tunnel enlargement, percentage diameter changes of more than 10% were defined as an enlarged tunnel. The magnitude of tunnel enlargement and the standard clinical evaluation were also evaluated.

RESULTS

There were no significant differences between groups in the incidences of anteromedial and posterolateral bone tunnel enlargement, both in the A-P and lateral views (2 × 2 Chi-squared test). The magnitude of femoral posterolateral bone tunnel enlargement was significantly greater in group A in the A-P view (p = 0.01) and lateral view (p = 0.03) (Mann Whitney U-test). Twelve months after surgery, the Lysholm score and Tegner activity level scale were not significantly different between the groups.

CONCLUSIONS

This prospective, clinical and radiographical study showed that early weight-bearing protocol after double-bundle ACL reconstruction with hamstring grafts might have the potential risk of significant postoperative femoral bone tunnel enlargement of the posterolateral bundle. There was no significant difference in clinical outcomes by postoperative non-weight-bearing period. To reduce and prevent the femoral bone tunnel enlargement, the comprehensive management could be considered and required to establish the suitable early stage rehabilitation protocol after surgery.

TRIAL REGISTRATION

Trial registration number; UMIN000036212 . Scientific title: Prospective comparisons of femoral tunnel enlargement with two different postoperative non weight bearing periods after double-bundle anterior cruciate ligament reconstruction with hamstring grafts. Registered date: 15 Mar 2019 (retrospectively registered).

Impaired neuromuscular control up to postoperative 1 year in operated and nonoperated knees after anterior cruciate ligament reconstruction

The current study was performed to assess serial changes in neuromuscular control until 1 year postoperatively in nonathletic patients undergoing anterior cruciate ligament reconstruction (ACLR).Ninety-six patients were included. Serial neuromuscular control tests were performed preoperatively, at 6 months, and 1 year postoperatively. Neuromuscular control was evaluated using acceleration time (AT) and dynamic postural stability (overall stability index, OSI). Functional activity levels were assessed using the Tegner activity-level scale.Preoperative AT of quadriceps and hamstrings in operated knees was 78.9 ± 6.4 and 86.5 ± 6.2 ms, respectively, which significantly reduced to 56.9 ± 2.0 and 62.5 ± 2.8 ms at 1 year (P = 0.006 and 0.002, respectively). In nonoperated knees, preoperative AT of quadriceps and hamstrings was 47.6 ± 1.7 and 56.5 ± 1.7 ms, respectively, which was significantly prolonged to 54.3 ± 2.0 and 67.9 ± 2.7 ms at 1 year (P = 0.02 and 0.001, respectively). Preoperative OSI of nonoperated knees was 1.2 ± 0.0°. It significantly increased to 1.5 ± 0.1° at 1 year (P < 0.001). In operated knees, preoperative OSI was 1.8 ± 0.1°. It significantly decreased to 1.4 ± 0.1° at 1 year (P = 0.001). Tegner scale at 6 months and 1 year were significantly lower than pre-operative scale (P < 0.001). AT and OSI on both knees showed significant negative correlation with Tegner scale at 6 months and 1 year.Neuromuscular control in both knees was not restored to preoperative levels of the nonoperated knees until 1 year after ACLR. Therefore, clinicians and physical therapists should attempt to enhance neuromuscular control in both nonoperated and operated knees.

Clinical measures associated with knee function over two years in young athletes after ACL reconstruction

PURPOSE

The purpose of this study was to investigate how patient-reported knee function changed over a two-year period in young athletes after anterior cruciate ligament reconstruction (ACLR) and return-to-sport (RTS), and to determine the impact of clinical measures, after controlling for demographic and surgical covariates.

METHODS

At the time of RTS after primary, unilateral ACLR, the following data were collected in 67 young athletes: Quadriceps (QF), hamstring (HS), and hip abduction (HA) strength; knee range-of-motion, effusion, and anterior laxity; and patient-reported function using the Knee injury and Osteoarthritis Outcome Score (KOOS). At two years post-RTS, patient-reported function was reevaluated using the KOOS. Absolute KOOS scores and proportions of participants meeting functional recovery cutoffs were compared between time-points. Multivariable linear regression was used to determine clinical measures at RTS associated with two-year post-RTS KOOS scores.

RESULTS

KOOS scores for all subscales were higher at two years post-RTS (all p < 0.003), and the proportions of participants demonstrating functional recovery were higher at two years post-RTS for the KOOS-Symptoms, KOOS-Sport, KOOS-QOL, and all KOOS subscales combined (all p < 0.03). After controlling for graft type, clinical measures at RTS associated with higher two-year post-RTS KOOS scores were: KOOS-Pain (lower HA peak torque); KOOS-Symptoms (higher QF strength symmetry and higher QF peak torque); and KOOS-ADL (lower HA peak torque).

CONCLUSIONS

In this cohort, after controlling for graft type, higher QF strength symmetry, higher involved-limb QF peak torque, and lower involved-limb HA peak torque from the time of RTS were associated with higher function at two years post-RTS.

Inferior graft maturity in the PL bundle after autograft hamstring double-bundle ACL reconstruction

PURPOSE

The purpose of this study was to evaluate the signal/noise quotient (SNQ) for graft maturation and the serial changes observed in the magnetic resonance imaging (MRI) findings after double-bundle (DB) anterior cruciate ligament (ACL) reconstruction using a hamstring tendon autograft at a minimum of 5 years after surgery.

METHODS

Forty-five patients who underwent DB ACL reconstruction between 2007 and 2010 were included in this prospective study. All participants underwent postoperative MRI at 3 weeks and 3, 6, 9 and 12, 18, 24, 36, 48 and 50 months. The signal intensity (SI) characteristics of the reconstructed graft were evaluated on oblique axial proton density-weighted MR imaging (PDWI) perpendicular to the grafts. The signal/noise quotient (SNQ) was calculated to quantitatively determine the normalized SI. The SNQ of the AMB and PLB was evaluated separately.

RESULTS

The mean SNQ of the AM bundle (AMB) continued to increase until 6 months after surgery (5.2 ± 1.2), and then gradually decreased and became well stabilized by 18 months (3.3 ± 0.5), after which it remained unchanged. On the other hand, the mean SNQ of the PL bundle (PLB) continued to increase until 9 months after surgery (6.2 ± 1.1), and then decreased incrementally and became well stabilized by 24 months (4.1 ± 0.5). The SI of PLB was significantly higher than that of AMB between 3 and 24 months (p = 0.04, 0.03, 0.01, 0.04, 0.02 and 0.03, respectively).

CONCLUSIONS

These results indicate that at least 18 months is needed after ACL reconstruction to sufficiently restore the SI of the AMB, while at least 24 months are needed to for the PLB. The SI of the PLB was significantly higher than that of the AMB at 3-24 months after surgery, indicating that the PLB showed inferior graft maturity to the AMB until 24 months after surgery. For clinical relevance, the correct understanding of serial changes in graft maturation may potentially be used in decision-making regarding a return to sports.

LEVEL OF EVIDENCE

Prospective case series, Level IV.

LARS versus hamstring tendon autograft in anterior cruciate ligament reconstruction: a single-centre, single surgeon retrospective study with 8 years of follow-up

PURPOSE

The choice of graft type in the anterior cruciate ligament (ACL) reconstruction remains a subject of controversy. The aim of this study was to assess the outcomes in ACL reconstructions performed using a four-strand hamstring tendon graft (4SHG) or a LARS ligament comparing the effectiveness of the two grafts at a medium follow-up of 8 years.

METHODS

This retrospective, single-centre, single surgeon study evaluated the clinical, functional and radiographic outcomes in 50 patients who underwent ACL reconstruction (25 4SHG and 25 LARS). Patients who underwent surgery after more than 6 months from injury and showed radiographically visible degenerative changes at time of surgery were excluded from the study.

RESULTS

None of the patients underwent re-surgery in the same knee. The range of motion of the operated knee, compared to the contralateral, was good for both groups. The anterior drawer test resulted negative in 21 patients (84%) in the LARS group and eight patients (32%) in the 4SHG group (P = 0.039). The Lachman test was negative in 19 patients (76%) in the LARS group and in 11 patients (44%) in the 4SHG group (P = 0.045). Although other results of ACL reconstruction measured by Lysholm scores, IKDC evaluation, Tegner scores and radiographic images showed using a LARS graft tended to be superior to using a 4SHG, there were no statistically significant differences calculated.

CONCLUSION

Our results suggest that 4 years after ACL reconstruction using a LARS ligament or 4SHG dramatically improves the function outcome, while the patients in the LARS group displayed a higher knee stability than those in the 4SHG group.

Long-term Comparison of Semitendinosus and Gracilis Tendon Versus Patellar Tendon Autografts for Anterior Cruciate Ligament Reconstruction: A 17-Year Follow-up of a Randomized Controlled Trial

BACKGROUND

Short-term and mid-term differences between hamstring and patellar tendon autografts for anterior cruciate ligament (ACL) reconstruction are well documented. Systematic reviews highlight the lack of long-term results between the two grafts.

HYPOTHESIS

Seventeen years after ACL reconstruction, no difference will be found in functional outcome, quality of life, and graft failure between patients with patellar tendon (PT) or semitendinosus and gracilis tendon (STG) autografts; however, a significant difference will be seen in the prevalence of osteoarthritis.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

Sixty-four patients were included in this prospective study (32 in each group). A single surgeon performed primary ACL reconstruction in alternating sequence. Forty-eight patients (24 in each group) were evaluated 17 years after ACL reconstruction: A clinical assessment was made based on the International Knee Documentation Committee (IKDC) form, instrumented laxity was measured with KT-1000 arthrometer, and radiography of the operated knee was conducted and assessed for degenerative disease. The Lysholm questionnaire and the Short Form-36 version 2 questionnaire were filled out by the patients.

RESULTS

At the 17-year follow-up, no statistically significant differences were seen with respect to graft failure (2 reruptures in the semitendinosus and gracilis tendon [STG] group [6.3%] and 3 reruptures in the PT group [9.4%]) and functional outcome. Increased instrumented laxity (>3 mm) measured with KT-1000 arthrometer was seen in significantly more patients in the STG group (8 in the STG group compared with 2 in the PT group; P = .03) with a mean side-to-side difference of 2.17 ± 1.86 mm in the STG group compared with 1.33 ± 1.93 mm in the PT group. A significant difference was found in frequency of knee osteoarthritis (OA)-100% in the PT group compared with 71% in the STG group ( P = .004). Patients in the PT group tended to have higher grade OA according to the IKDC grading system, with an average grade of 1.46 in the PT group compared with 1 in the STG group ( P = .055). The degenerative changes in the PT group were more common in the medial and patellofemoral compartments ( P = .003 and P = .04, respectively).

CONCLUSION

Both autografts provided good to excellent subjective outcomes. No significant differences were noted in graft failure and clinical instability. However, significantly more patients in the STG group had increased instrumented anteroposterior translation measured with KT-1000 arthrometer, and there was a greater prevalence of knee OA at 17 years after surgery in the PT group.

ACL reconstruction with hamstring tendon autograft and accelerated brace-free rehabilitation: a systematic review of clinical outcomes

OBJECTIVE

To investigate the clinical outcomes after hamstring tendon autograft ACL reconstruction (ACLR) with accelerated, brace-free rehabilitation.

DESIGN

Systematic review according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines.

DATA SOURCES

Embase, MEDLINE Ovid, Web of Science, Cochrane CENTRAL and Google scholar from 1 January 1974 to 31 January 2017.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Study designs reporting outcomes in adults after arthroscopic, primary ACLR with hamstring autograft and accelerated, brace-free rehabilitation.

RESULTS

Twenty-four studies were included in the review. The clinical outcomes after hamstring tendon autograft ACLR with accelerated brace-free rehabilitation were the following: (1) early start of open kinetic exercises at 4 weeks in a limited range of motion (ROM, 90°-45°) and progressive concentric and eccentric exercises from 12 weeks did not alter outcomes, (2) gender and age did not influence clinical outcomes, (3) anatomical reconstructions showed better results than non-anatomical reconstructions, (4) there was no difference between single-bundle and double-bundle reconstructions, (5) femoral and tibial tunnel widening occurred, (6) hamstring tendons regenerated after harvest and (7) biological knowledge did not support return to sports at 4-6 months.

CONCLUSIONS

After hamstring tendon autograft ACLR with accelerated brace-free rehabilitation, clinical outcome is similar after single-bundle and double-bundle ACLR. Early start of open kinetic exercises at 4 weeks in a limited ROM (90°-45°) and progressive concentric and eccentric exercises from 12 weeks postsurgery do not alter clinical outcome. Further research should focus on achievement of best balance between graft loading and graft healing in the various rehabilitation phases after ACLR as well as on validated, criterion-based assessments for safe return to sports.

LEVEL OF EVIDENCE

Level 2b; therapeutic outcome studies.