Editorial Commentary: Bone Marrow Aspirate Concentrate May Accelerate Anterior Cruciate Ligament Allograft Using Bone Patellar Tendon Bone Maturation on Magnetic Resonance Imaging, but Clinical Differences Have Not Been Demonstrated

Revision Anterior Cruciate Ligament Reconstruction in Pediatric and Adolescent Patients Yields Low Rates of Graft Failure and Good Functional Scores, but Low Rates of Return to Sport: A Systematic Review

PURPOSE

To evaluate outcomes after revision anterior cruciate ligament reconstruction (ACLR) in pediatric and adolescent patients in terms of graft failure rate and functional patient outcomes.

METHODS

A systematic review of Cochrane, Embase, Scopus, Ovid, and PubMed databases was performed for all original clinical studies that reported outcomes of pediatric and adolescent patients undergoing revision ACLR. Non-English studies and studies not reporting both graft failure rates and an additional outcome measure were excluded. We evaluated patient demographics, injury mechanisms, surgical technique characteristics, concomitant injuries, failure rates, patient-reported outcome measures (PROMs), complications, and return to sports rates. Risk of bias (ROB) was assessed with the methodological index for nonrandomized studies (MINORS).

RESULTS

Five studies with a total of 239 knees in 234 patients were included. Failure of the revision ACLR ranged from 9% to 21%. Return to previous level of activity ranged between 27% and 68%. PROMs were variable, with good Lysholm Knee Scoring Scale score (range 84.5-93.7), moderate Tegner Activity Score (range 5.5-9.0), and good International Knee Documentation Committee knee scores (range 79.9-80.0). Allograft was used in 48% of revisions, followed by bone patellar tendon bone autograft in 34%, and hamstrings (HS) autograft in 14%. Meniscus injury and cartilage injury was present in 53.1% to 92.5% and 5.5% to 59.4% of knees, respectively. Gwet's AC1 coefficient was 0.89, indicating a high degree of interrater reliability. The average MINORS score was 6, and heterogeneity was low (I2 = 9%). The included studies did not present with sufficient detail to disaggregate clinical outcomes by patient sex.

CONCLUSIONS

Revision ACLR yields a graft failure ranging from 9 to 20%. Revision patients experience good PROMs but low rates of return to preinjury level of sport. Further, revision ACLR was associated with high rates of intra-articular damage and relatively low rates of meniscal repair at the time of second surgery.

LEVEL OF EVIDENCE

Level IV, systematic review of Level IV studies.

Optimizing repair of tendon ruptures and chronic tendinopathies: Integrating the use of biomarkers with biological interventions to improve patient outcomes and clinical trial design

Tendons are dense connective tissues of the musculoskeletal system that link bones with muscles to foster mobility. They have complex structures and exist in varying biomechanical, metabolic and biological environments. In addition, tendon composition and mechanical properties can change over the lifespan as an individual ages. Many tendons function in high stress conditions with a low vascular and neuronal supply, conditions often leading to development of chronic tendinopathies, and in some cases, overt rupture of the tissues. Given their essential nature for human mobility and navigation through the environment, the effective repair and regeneration of different tendons after injury or damage is critical for quality of life, and for elite athletes, the return to sport participation at a high level. However, for mainly unknown reasons, the outcomes following injury are not always successful and lead to functional compromise and risk for re-injury. Thus, there is a need to identify those patients who are at risk for developing tendon problems, as well those at risk for poor outcomes after injury and to design interventions to improve outcomes after injury or rupture to specific tendons. This review will discuss recent advances in the identification of biomarkers prognostic for successful and less successful outcomes after tendon injury, and the mechanistic implications of such biomarkers, as well as the potential for specific biologic interventions to enhance outcomes to improve both quality of life and a return to participation in sports. In addition, the implication of these biomarkers for clinical trial design is discussed, as is the issue of whether such biomarkers for successful healing of one tendon can be extended to all tendons or are valid only for tendons in specific biomechanical and biological environments. As maintaining an active lifestyle is critical for health, the successful implementation of these advances will benefit the large number of individuals at risk.