Jason P. Zlotnicki

Biologic Treatments for Sports Injuries II Think Tank—Current Concepts, Future Research, and Barriers to Advancement, Part 1 Biologics Overview, Ligament Injury, Tendinopathy

Biologic therapies, including stem cells, platelet-rich plasma, growth factors, and other biologically active adjuncts, have recently received increased attention in the basic science and clinical literature. At the 2015 AOSSM Biologics II Think Tank held in Colorado Springs, Colorado, a group of orthopaedic surgeons, basic scientists, veterinarians, and other investigators gathered to review the state of the science for biologics and barriers to implementation of biologics for the treatment of sports medicine injuries. This series of current concepts reviews reports the summary of the scientific presentations, roundtable discussions, and recommendations from this think tank.

Biologic Treatments for Sports Injuries II Think Tank—Current Concepts, Future Research, and Barriers to Advancement, Part 3: Articular Cartilage

Focal chondral defects of the articular surface are a common occurrence in the field of orthopaedics. These isolated cartilage injuries, if not repaired surgically with restoration of articular congruency, may have a high rate of progression to posttraumatic osteoarthritis, resulting in significant morbidity and loss of function in the young, active patient. Both isolated and global joint disease are a difficult entity to treat in the clinical setting given the high amount of stress on weightbearing joints and the limited healing potential of native articular cartilage. Recently, clinical interest has focused on the use of biologically active compounds and surgical techniques to regenerate native cartilage to the articular surface, with the goal of restoring normal joint health and overall function. This article presents a review of the current biologic therapies, as discussed at the 2015 American Orthopaedic Society for Sports Medicine (AOSSM) Biologics Think Tank, that are used in the treatment of focal cartilage deficiencies. For each of these emerging therapies, the theories for application, the present clinical evidence, and specific areas for future research are explored, with focus on the barriers currently faced by clinicians in advancing the success of these therapies in the clinical setting.

Validation of Quantitative Measures of Rotatory Knee Laxity.

Background: Prior attempts to quantify the pivot-shift examination have been too invasive or impractical for clinical use. A noninvasive method for quantifying rotatory knee laxity is needed. Hypothesis: Greater quantitative measurements of rotatory knee laxity (both of the involved knee as well as compared with the contralateral healthy knee) are associated with an increasing clinical pivot-shift grade. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 103 patients undergoing anatomic single-bundle anterior cruciate ligament (ACL) reconstruction at 4 international centers underwent a standardized pivot-shift test preoperatively on both knees while anesthetized. Clinical grading of the pivot shift was performed according to the International Knee Documentation Committee (IKDC) knee ligament rating system. Two different quantitative technologies were used to measure rotatory knee laxity: an inertial sensor and an image analysis were independently used to measure tibial acceleration and lateral compartment translation, respectively, during the pivot-shift test. Patients were dichotomized to “high-grade” (abnormal and severely abnormal) or “low-grade” (normal and nearly normal) rotatory knee laxity groups based on the clinical pivot-shift test result of the involved side. Tibial acceleration and lateral compartment translation of the involved knee and the side-to-side difference between the involved and contralateral knees were separately compared between the high- and low-grade rotatory knee laxity groups utilizing t tests; significance was set at P < .05. Results: Forty-three patients were in the low-grade rotatory knee laxity group, and 60 patients were in the high-grade rotatory knee laxity group. Patients in the high-grade knee laxity group had significantly higher lateral compartment translation as measured with the image analysis (involved knee: 3.8 ± 2.3 mm; side-to-side difference: 2.5 ± 2.4 mm) compared with patients in the low-grade group (involved knee: 2.0 ± 1.4 mm; side-to-side difference: 1.4 ± 1.5 mm) (both P < .01). As measured with the inertial sensor, tibial acceleration for patients in the high-grade group was significantly higher (involved knee: 7.2 ± 5.3 m/s2; side-to-side difference: 4.2 ± 5.4 m/s2) compared with patients in the low-grade group (involved knee: 4.2 ± 1.6 m/s2; side-to-side difference: 1.2 ± 1.2 m/s2) (both P < .01). Conclusion: The inertial sensor and image analysis techniques were able to detect differences between low- and high-grade pivot-shift test results. A quantitative assessment of the pivot-shift test could augment the diagnosis of an ACL injury and improve the ability to detect changes in rotatory knee laxity over time.

Biologic Treatments for Sports Injuries II Think Tank—Current Concepts, Future Research, and Barriers to Advancement, Part 2: Rotator Cuff

Rotator cuff tears are common and result in considerable morbidity. Tears within the tendon substance or at its insertion into the humeral head represent a considerable clinical challenge because of the hostile local environment that precludes healing. Tears often progress without intervention, and current surgical treatments are inadequate. Although surgical implants, instrumentation, and techniques have improved, healing rates have not improved, and a high failure rate remains for large and massive rotator cuff tears. The use of biologic adjuvants that contribute to a regenerative microenvironment have great potential for improving healing rates and function after surgery. This article presents a review of current and emerging biologic approaches to augment rotator cuff tendon and muscle regeneration focusing on the scientific rationale, preclinical, and clinical evidence for efficacy, areas for future research, and current barriers to advancement and implementation.

Basic biomechanic principles of knee instability

Motion at the knee joint is a complex mechanical phenomenon. Stability is provided by a combination of static and dynamic structures that work in concert to prevent excessive movement or instability that is inherent in various knee injuries. The anterior cruciate ligament (ACL) is a main stabilizer of the knee, providing both translational and rotatory constraint. Despite the high volume of research directed at native ACL function, pathogenesis and surgical reconstruction of this structure, a gold standard for objective quantification of injury and subsequent repair, has not been demonstrated. Furthermore, recent studies have suggested that novel anatomic structures may play a significant role in knee stability. The use of biomechanical principles and testing techniques provides essential objective/quantitative information on the function of bone, ligaments, joint capsule, and other contributing soft tissues in response to various loading conditions. This review discusses the principles of biomechanics in relation to knee stability, with a focus on the objective quantification of knee stability, the individual contributions of specific knee structures to stability, and the most recent technological advances in the biomechanical evaluation of the knee joint.

Knee instability scores for ACL reconstruction

Despite abundant biological, biomechanical, and clinical research, return to sport after anterior cruciate ligament (ACL) injury remains a significant challenge. Residual rotatory knee laxity has been identified as one of the factors responsible for poor functional outcome. To improve and standardize the assessment of knee instability, a variety of instability scoring systems is available. Recently, devices to objectively quantify static and dynamic clinical exams have been developed to complement traditional subjective grading systems. These devices enable an improved evaluation of knee instability and possible associated injuries. This additional information may promote the development of new treatment algorithms and allow for individualized treatment. In this review, the different subjective laxity scores as well as complementary objective measuring systems are discussed, along with an introduction of injury to an individualized treatment algorithm.

Kinematic outcomes following ACL reconstruction

Anterior cruciate ligament (ACL) reconstruction aims to restore the translational and rotational motion to the knee joint that is lost after injury. However, despite technical advancements, clinical outcomes are less than ideal, particularly in return to previous activity level. A major issue is the inability to standardize treatment protocols due to variations in materials and approaches used to accomplish ACL reconstruction. These include surgical techniques such as the transtibial and anteromedial portal methods that are currently under use and the wide availability of graft types that will be used to reconstruct the ACL. In addition, concomitant soft tissue injuries to the menisci and capsule are frequently present after ACL injury and, if left unaddressed, can lead to persistent instability even after the ACL has been reconstructed. Advances in the field of biomechanics that help to objectively measure motion of the knee joint may provide more precise data than current subjective clinical measurements. These technologies include extra-articular motion capture systems that measure the movement of the tibia in relation to the femur. With data gathered from these devices, a threshold for satisfactory knee stability may be established in order to correctly identify a successful reconstruction following ACL injury.

Shoulder Injuries: Conservative Management, Operative Management, and Return to Sport

Shoulder injuries are common in the athletic population. The aging athlete represents a unique population as shoulder pathologies encountered can differ significantly from younger athletes and, therefore, alter evaluation and optimal management. As life expectancy increases and the population of older patients engaged in active lifestyles increases, the aging athlete will inevitably make up an ever-increasing subset of athletes who seek orthopedic care. As with all athletes, optimal management of shoulder injuries in the aging athlete should focus on optimizing long-term functional outcomes while preserving pre-injury activity level and athletic participation. This chapter will discuss five of the most common conditions that affect the aging athlete population, including pathology of the superior labrum and long head biceps tendon, shoulder dislocation, impingement and rotator cuff injury, acromioclavicular joint dislocation instability and arthritis, and glenohumeral osteoarthritis. Discussion will be centered around the best evidence-based recommendations for patient evaluation, non-operative management, and operative management with focus on functional outcomes and return to sport.

Is Lateral Femoral Notch Depth Associated with Rotatory Instability in ACL Deficient Knees: A Quantitative Pivot Shift Analysis

Objectives: Persistent rotatory knee instability after anterior cruciate ligament (ACL) reconstruction is relatively common. While the causes of this persistent instability are multifactorial, bony morphologic characteristics have been proposed to play a role. Therefore, the purpose of this study was to evaluate the relationship between the well-described lateral femoral notch (LFN) depth and quantitative measures of rotatory knee stability. We hypothesized that greater LFN depth would be associated with increased rotatory knee instability. Methods: A consecutive series of patients undergoing primary ACL reconstruction at our university medical center from June 2014 to April 2016 were analyzed. Inclusion criteria included primary ACL tear, no concurrent ligamentous or bony injury requiring operative treatment, no history of previous knee injury or surgery to the ACL-injured extremity, and no history of injury or surgery to the contralateral knee. A standardized pivot shift test was performed by the senior surgeon preoperatively under anesthesia in both knees and quantified using tablet image analysis software and accelerometer sensors as previously described and validated. Lateral knee radiographs and sagittal magnetic resonance images (MRI) of the injured knee were evaluated for depth of the LFN as previously described. A line tangent to the lateral femoral condyle articular surface was drawn across the notch. Notch depth was measured perpendicular from this line to the deepest point of the LFN. Pearson correlation coefficient was used to analyze correlations between continuous variables. Chi-square test was used to analyze relationships between notch depth and presence/absence of medial or lateral meniscus tears. Analyses were performed with SPSS 22.0 and significance was set at a p<0.05. Results: Fifty patients met inclusion criteria and were included in this study (mean age 24 years, range 13-45; 28 females, 22 males). Mean LFN depth as measured via x-ray was 0.8 mm (SD=0.63, n=50) and via MRI was 1.0 mm (SD=0.73, n=47). Twenty-two (44%) patients had a medial meniscus tear and 27 (54%) had a lateral meniscus tear. LFN on x-ray had moderate but significant positive correlations with ipsilateral lateral compartment acceleration (r=0.402, p=0.004) and acceleration side-to-side differences (r=0.407, p=0.003). LFN depth on MRI had moderate but significant positive correlations with ipsilateral lateral compartment acceleration (r=0.334, p=0.022) and acceleration side-to-side differences (r=0.363, p=0.012). LFN depth on x-ray was significantly associated with the presence of a lateral meniscus tear (p=0.014). There were no significant associations between LFN depth (x-ray or MRI) on ipsilateral or contralateral lateral compartment translation, contralateral lateral compartment acceleration, or the presence of medial meniscus tears. Conclusion: The results from this study demonstrated that a well described bony morphologic feature - LFN depth - was correlated with higher lateral compartment acceleration as measured by quantitative pivot shift analysis. Furthermore, greater LFN depth was associated with an increased incidence of lateral meniscus tears, which supports findings from previous studies. Assessment of LFN depth may help clinicians identify patients with greater rotatory instability prior to ACL reconstruction and potentially direct surgical treatment to account for additional rotatory knee instability. Table 1: Mean Quantitative Pivot Shift Values of the Injured and Uninjured Knee Injured Uninjured Side-to-Side Difference Compartment Acceleration (m/s2) 5.14 (SD=0.73) 3.45 (SD=0.95) 1.68 (SD=2.09) Lateral Compartment Translation (mm) 3.67 (SD=2.30) 1.22 (SD=0.75) 2.46 (SD=2.24)

Anterior-Posterior Translation and Axial Rotation of the Fibula are Significantly Increased with Sequential Disruption of the Syndesmosis

Category: Ankle, Sports, Trauma Introduction/Purpose: Injury to the Anterior inferior tibiofibular ligament (AITFL), Posterior inferior tibiofibular ligament (PITFL) and Interosseus membrane (IOM) predicts residual symptoms in ankle sprains. Limited kinematic knowledge of the tibiofibular joint results in missed diagnosis and poor clinical outcomes. Lateral fibular displacement on radiologic assessment signifies syndesmotic disruption which dictates operative management. Previous studies demonstrated that fibular motion is multiplanar after injury. The objective of this study is to determine increases in fibular motion with sequential syndesmotic injury and the contribution of the AITFL. Methods: Five fresh-frozen human cadaveric tibial plateau-to-toe specimens with a mean age of 58 years (range 38-73 years) were tested using a 6-degree-of-freedom robotic testing system. The tibia and calcaneus were rigidly fixed. The subtalar joint was fused. The full fibular length was maintained and fibular motion was unconstrained. A 5 Nm external rotation and 5 Nm inversion moment were applied to the ankle at 0°, 15°, and 30° plantarflexion and 10° dorsiflexion. The motion of the fibula was tracked by a 3D optical tracking system. Outcome variables included fibular medial-lateral (ML) translation, anterior-posterior (AP) translation, and external rotation (ER) during each applied moment and flexion angle in the following conditions: 1) intact ankle, 2) AITFL transected, 3) PITFL and IOM transected. Statistical analysis included an ANOVA with a post-hoc Tukey analysis to compare the changes in fibular motion between the intact and injury models at each applied moment and flexion angle (*p<0.05). Results: The only significant differences in fibular motion were during the 5 Nm inversion moment. The posterior translation of the fibula was significantly greater with AITFL injury compared to the intact ankle at 15° and 30° plantarflexion. Significant increases in posterior translation between the intact ankle and AITFL, PITFL, and IOM injury existed at 0°, 15°, and 30° plantarflexion. No significant motion differences were observed between the AITFL injury and combined injury at any condition. When comparing the intact ankle and combined injury, significant increases in ER existed at 0° and 30° plantarflexion and 10° dorsiflexion. The only significant difference in ER between the intact ankle and AITFL injury existed at 0° plantarflexion. Conclusion: This study showed that transecting the AITFL resulted in the largest increases in fibular motion with only minimal further increases after complete syndesmotic injury. Fibular displacement was primarily in the sagittal plane. This study utilized a novel setup with unconstrained motion in a full length, intact fibula. Measuring ML translation alone could underestimate sagittal and rotational instability of the syndesmosis in AITFL injuries. Evaluating fibular AP translation and ER are not part of current standard diagnostic protocols. Physicians may consider more aggressive treatment of isolated AITFL injuries.