Part One: Lower extremity, basic science, and cost-effectiveness
The 2016 Annual Meeting featured innovative and thought-provoking research in all fields of orthopaedics. Summarized here are highlights from sports medicine and arthroscopy presentations covering lower extremity, basic science, and cost-effectiveness. In May, we will feature studies focused on upper extremity, rehabilitation, and return-to-play issues.
Given the many high-quality presentations at this year's meeting, this review is far from comprehensive, but our hope is that it will serve as an illustrative cross-section.
Robert Westermann, MD, et al looked at meniscal repairs performed at the time of anterior cruciate ligament (ACL) reconstruction, in Poster 402. In this meta-regression analysis, performed at the University of Iowa, the authors included 22 studies reporting on the outcomes following meniscal repair with either all-inside or inside-out techniques performed at the time of ACL reconstruction, with a minimum of 2-year follow-up. The study involved 1,100 patients and found that the failure rate of inside-out repairs at 2 years was 10 percent, while the failure rate of all-inside repairs was 16 percent. The authors recommended that inside-out repairs remain the gold standard when evaluating new treatment techniques. The relatively low volume of studies reporting outcomes after meniscus repairs underscores the need for further research in this area.
Several studies focused on the role of the anterolateral structures of the knee relative to rotatory stability in the setting of an ACL tear. Researchers at the University of Pittsburgh presented a multidisciplinary project to study the structure and function of the anterolateral capsule, in Scientific Exhibit 72. Anatomical, histological, and biomechanical properties of anterolateral structures were investigated in a multifaceted translational project that ranged from basic science to clinical care. Authors Ata Rahnemai-azar, MD, and Volker Musahl, MD, summarized their findings, stating that the "lateral capsule has a secondary role in the rotatory stability of the knee; however, the decision to perform additional extra-articular reconstruction surgeries should be carefully determined, and future research is needed to appropriately address knee rotational instability for patients."
In another knee study, Paper 362, Timothy Lording, MD, et al demonstrated that the lateral meniscus posterior root also provides substantial anterolateral stability in the setting of ACL injury. Further, in Paper 768, Marco Nitri, MD, et al observed that anterolateral ligament reconstruction performed concurrently with ACL reconstruction restored the rotatory stability of the knee better than ACL reconstruction alone.
Poster 434 by Melissa M. Allen, MD, and colleagues presented findings for second ACL injury in female athletes. In this study out of Mayo, 180 female athletes—90 female soccer players and 90 nonsoccer players—who had undergone ACL reconstruction were retrospectively reviewed. At an average 5.8-year follow-up, the authors found that the soccer cohort sustained significantly more ACL tears on both the surgical knee (11 percent versus 1 percent, P < 0.01) and contralateral knee (17 percent versus 4 percent, P < 0.01) compared to the nonsoccer players. Interestingly, return to soccer as well as relatively older age (odds ratio of 1.9 per year) were significant risk factors for ACL re-tear, but not for contralateral ACL tear. This information will be helpful in counseling female athletes, particularly those participating in soccer, on their chances of re-rupture and contralateral knee injury following ACL reconstruction.
In a study performed at the University of Missouri, James L. Cook DVM, PhD, et al compared canine knees with a normal ACL, a partially torn ACL, and a denervated ACL. In Paper 428, they reported that a canine knee with a denervated ACL showed similar joint dysfunction and osteoarthritic changes as that of a partially ACL-deficient knee.
Christopher Cooke, MD, et al exposed human chondrocytes to bupivacaine, ketolorac, morphine sulfate, and acetaminophen in vitro. Their findings, as reported in Poster 457, "Four Chemical Agents for Pain: Are They Cytotoxic for Osteoarthritic Human Chondrocytes?" demonstrated chondrotoxicity with exposure to bupivacaine and acetaminophen. The authors suggested that ketorolac and morphine sulfate may be better agents to use for intra-articular injection after arthroscopic surgery.
In "The Cost-Effectiveness of Anterior Cruciate Ligament Reconstruction in Competitive Athletes" (Poster 420), first author Bruce Stewart, MD, presenting author Amit Momaya, MD, and colleagues utilized Markov models to compare the cost-effectiveness of ACL reconstruction versus conservative management with physical therapy. The analysis calculated costs and outcomes over a 6-year time horizon, and was based on data from peer-reviewed publications as well as their own institutional data. The incremental cost effectiveness ratio (ICER) for ACL reconstruction was $22,702 per quality of life year (QALY) gained, lower than the $50,000 per QALY "willingness to pay" threshold often cited in the literature. The ICER was sensitive to quality of life of returning to play or not returning to play, costs, and follow-up time. This study supported previous studies showing ACL reconstruction is the preferred method of treatment for ACL injury, and demonstrates that it is a more cost-effective option as well.
In addition to the presentations highlighted here, there were dozens of video presentations and scientific exhibits that complement and augment the findings discussed in all of the original research podium and poster presentations. Hot topics this year appeared to involve advances in hip arthroscopy, techniques in advanced shoulder reconstruction, and the growing use of biologic therapy across all areas of sports medicine and arthroscopy.
Rachel M. Frank, MD, is a PGY-5 resident at Rush University Medical Center in Chicago. She will be doing a sports medicine fellowship next year at Rush. Jeremy M. Burnham, MD, is a PGY-5 resident at the University of Kentucky in Lexington. He will be doing a sports medicine fellowship next year at the University of Pittsburgh Medical Center.
- All-Inside vs. Inside-Out Meniscal Repair with Concurrent ACL Reconstruction: A Meta-Regression Analysis. Robert W. Westermann, MD, Iowa City, IA; Kyle Duchman, MD, Iowa City, IA; Natalie A. Glass, PhD, Iowa City, IA; Annunziato Amendola, MD, Iowa City, IA; Brian R. Wolf, MD, Iowa City, IA. 2016 AAOS Annual Meeting, Poster 402.
- The Role of Anterolateral Capsule on Stability of the Knee: A Multidisciplinary Approach. Amir Ata Rahnemai Azar, MD, Pittsburgh, PA; Daniel Guenther, MD, Pittsburgh, PA; Sebastian Irarrazaval, Pittsburgh, PA; Fabio V. Arilla, MD, Estancia Velha, Brazil Kevin M. Bell, MS, Pittsburgh, PA; James J. Irrgang, PhD, Pittsburgh, PA Richard E. Debski, PhD, Pittsburgh, PA; Freddie H. Fu, MD, Pittsburgh, PA; Volker Musahl, MD, Pittsburgh, PA; 2016 AAOS Annual Meeting, Scientific Exhibit 72.
- The Role of the Lateral Meniscus Posterior Root in Providing Anterolateral Knee Joint Stability. Timothy Lording, MD, Malvern, Australia; Gillian G. Corbo, London, ON, Canada; Timothy Burkhart, PhD, London, ON, Canada; Alan Getgood, MD, FRCS (Ortho), London, ON, Canada. 2016 AAOS Annual Meeting, Paper 362.
- Robotic Assessment of Anterolateral Ligament: Reconstruction of the Anterolateral and Anterior Cruciate Ligament. Marco Nitri, MD, Vail, CO; Matthew Rasmussen, BS, Vail, CO; Brady T. Williams, BS, Vail, CO; Samuel Moulton, BA, Eugene, OR; Raphael Serra Cruz, MD, Vail, CO; Grant Dornan, MSc, Vail, CO; Mary T. Goldsmith, MSc, Vail, CO; Robert F. LaPrade, MD, PhD, Vail, CO. 2016 AAOS Annual Meeting, Paper 768.
- Increased Risk of Second Anterior Cruciate Ligament Injury for Female Soccer Players. Melissa M. Allen, MD, Rochester, MN; Alexander H. King, BS, Rochester, MN; Michael J. Stuart, MD, Rochester, MN; Bruce A. Levy, MD, Rochester, MN; Diane L. Dahm, MD, Rochester, MN; Aaron J. Krych, MD, Rochester, MN. 2016 AAOS Annual Meeting, Poster 434.
- Does ACL Innervation Matter for Joint Function and Development of OA? James L. Cook, DVM, PhD, Columbia, MO; Christopher Nagelli, Columbus, OH; Keiichi Kuroki, DVM, PhD, Columbia, MO; Chantelle Bozynski, DVM, MSc, Columbia, MO; Timothy E. Hewett, PhD, Columbus, OH. 2016 AAOS Annual Meeting, Paper 428.
- Four Chemical Agents for Pain: Are They Cytotoxic for Osteoarthritic Human Chondrocytes? Christopher Cooke, MD, Troy, MI; Nancy M. Jackson, Southfield, MI; Patrick Keating, BS, Warren, MI; Jeffrey Flynn, Southfield, MI; David C. Markel, MD, Southfield, MI; Stephen E. Lemos, MD, PhD, Warren, MI. 2016 AAOS Annual Meeting, Poster 457.
- The Cost-Effectiveness of Anterior Cruciate Ligament Reconstruction in Competitive Athletes. Bruce A. Stewart, MD, Holland, Michigan; Amit Momaya, MD, Homewood, AL; Marc D. Silverstein, MD, Mashpee, MA; David M. Lintner, MD, Houston, TX. 2016 AAOS Annual Meeting, Poster 420.