Kyle E. Hammond

Anatomic Landmarks Utilized for Physeal-Sparing, Anatomic Anterior Cruciate Ligament Reconstruction An MRI-Based Study

BACKGROUND Anterior cruciate ligament (ACL) injury and reconstruction in the skeletally immature patient are becoming more common. The purpose of this study was to develop a reproducible anatomic ACL reconstruction technique, based on intra-articular and extra-articular landmarks, that reliably produces a femoral tunnel of adequate length and diameter while avoiding the distal femoral physis. METHODS Magnetic resonance images (MRIs) of one hundred and eighty-eight children (age range, six to seventeen years) were evaluated. Two extra-articular landmarks, the femoral insertion of the popliteus tendon and the lateral femoral epicondyle, and one intra-articular landmark, the central portion of the femoral footprint of the ACL, were identified. Computer software was used to plot these landmarks in all three planes and to draw lines representing two potential femoral tunnels. The first line connected the center of the ACL femoral footprint with the insertion of the popliteus tendon, and the second connected the center of the ACL femoral footprint with the lateral femoral epicondyle. The length of each tunnel, the shortest distance from the center of each tunnel to the distal femoral physis, and the height of the lateral femoral condyle from the physis to the chondral surface and to the base of the cartilage cap were calculated. A three-dimensional MRI reconstruction was used to confirm that placement of a femoral tunnel with use of the chosen landmarks would avoid the distal femoral physis. RESULTS The mean distance from the center of the preferred ACL tunnel, which connected the center of the ACL femoral footprint with the insertion of the popliteus tendon, to the distal femoral physis was 12 mm, independent of sex (p = 0.94) or age, and the shortest distance was 8 mm. The length of this proposed tunnel averaged 30.1 mm in the boys and 27.4 mm in the girls (p < 0.001), and it averaged 25.4 mm at an age of six years and 29.7 mm at an age of seventeen years. The mean distance from the center of the alternative tunnel, which connected the center of the ACL femoral footprint with the lateral epicondyle, to the distal femoral physis was 8.8 mm in the boys and 8.9 mm in the girls (p = 0.55). The mean length of this alternative tunnel was 34.3 mm in the boys and 31.6 mm in the girls (p < 0.001). CONCLUSIONS Drilling from the center of the ACL femoral footprint to the insertion of the popliteus tendon would have resulted in a mean tunnel length of 27 to 30 mm, and it would have allowed the safe placement of a femoral tunnel at least 7 mm in diameter in a patient six to seventeen years old. The center of the ACL femoral footprint and the popliteus insertion are easily identifiable landmarks and will allow safe, reproducible, anatomic ACL reconstruction in the skeletally immature patient.

A Biomechanical Analysis of Point of Failure During Lateral-Row Tensioning in Transosseous-Equivalent Rotator Cuff Repair

PURPOSE The purpose of this study was to determine the maximum load and point of failure of the construct during tensioning of the lateral row of a transosseous-equivalent (TOE) rotator cuff repair. METHODS In 6 fresh-frozen human shoulders, a TOE rotator cuff repair was performed, with 1 suture from each medial anchor passed through the tendon and tied in a horizontal mattress pattern. One of 2 limbs from each of 2 medial anchors was pulled laterally over the tendon. After preparation of the lateral bone for anchor placement, the 2 limbs were passed through the polyether ether ketone (PEEK) eyelet of a knotless anchor and tied to a tensiometer. The lateral anchor was placed into the prepared bone tunnel but not fully seated. Tensioning of the lateral-row repair was simulated by pulling the tensiometer to tighten the suture limbs as they passed through the eyelet of the knotless anchor. The mode of failure and maximum tension were recorded. The procedure was then repeated for the second lateral-row anchor. RESULTS The mean load to failure during lateral-row placement in the TOE model was 80.8 ± 21.0 N (median, 83 N; range, 27.2 to 115.8 N). There was no statistically significant difference between load to failure during lateral-row tensioning for the anterior and posterior anchors (P = .84). Each of the 12 constructs failed at the eyelet of the lateral anchor. Retrieval analysis showed no failure of the medial anchors, no medial suture cutout through the rotator cuff tendon, and no signs of gapping at the repair site. CONCLUSIONS Our results suggest that the medial-row repair does not appear vulnerable during tensioning of the lateral row of a TOE rotator cuff repair with the implants tested. However, surgeons should exercise caution when tensioning the lateral row, especially when lateral-row anchors with PEEK eyelets are implemented. CLINICAL RELEVANCE For this repair construct, the findings suggest that although the medial row is not vulnerable during lateral-row tensioning of a TOE rotator cuff repair, lateral-row anchors with PEEK eyelets appear vulnerable to early failure.

Lateral Femoral Cortical Breach During Anterior Cruciate Ligament Reconstruction: A Biomechanical Analysis

PURPOSE The purpose of our study was to determine whether secondary fixation is needed when lateral femoral wall breach occurs and whether the diameter of the femoral tunnel affects the cyclical and ultimate load to failure of 3 different suspensory fixation devices. METHODS Sixty fresh-frozen porcine femora were dissected to isolate the anterior cruciate ligament (ACL) footprint. Femoral ACL tunnels were then drilled at diameters of 7, 8, 9, and 10 mm. We conducted 5 separate cyclical and ultimate load testing trials, at each tunnel diameter, for 3 different cortical suspension devices. RESULTS The mean load to failure decreased as the tunnel size enlarged for all 3 devices. In 7-mm tunnels, mean failure load ranged from 1,163.7 to 1,455.0 N across the 3 devices; in 8-mm tunnels, 1,154.7 to 1,643.2 N; in 9-mm tunnels, 820.8 to 1,125.21 N; and in 10-mm tunnels, 314.7 to 917.8 N. Modes of failure also varied as the tunnel sizes enlarged. The ultimate load was not different among the 3 manufacturers (P = .08), but there was a difference in the ultimate load across the 4 tunnel diameters (P < .05), except when we compared the 7-mm tunnel with the 8-mm tunnel (P = .91). CONCLUSIONS With 7- and 8-mm-diameter tunnels, failure loads with each of the suspensory devices tested exceeded the documented interference screw load to failure. CLINICAL RELEVANCE Our findings suggest that, for soft-tissue ACL grafts, femoral tunnels of 8 mm or less can be drilled through the lateral femoral cortex while still using a suspensory device for graft fixation. With pediatric, double-bundle, and anatomic ACL reconstructions, smaller and shorter tunnels are routinely used. Thus, breaching the lateral cortex when using suspensory fixation may increase tunnel length while still achieving stable fixation.

Inter-observer and intra-observer reliability of the Risser sign in a metropolitan scoliosis screening program.

Background: Risser staging is one of several criteria used in scoliosis screening programs. This study aimed to evaluate the reliability of a radiologist’s Risser interpretations from a large metropolitan scoliosis-screening program when compared to interpretations of 2 pediatric orthopaedic surgeons and 2 orthopaedic residents. Methods: During the 2008 to 2009 school year, 275 students were reviewed as part of a metropolitan scoliosis-screening program. 100 of the radiographs were randomly chosen and de-identified for inclusion. Two attending orthopaedic surgeons and 2 orthopaedic residents independently interpreted the films on 3 occasions and assigned each a Risser stage. Inter- and intra-rater analyses using Kappa statistics were performed to determine the reliability of the Risser stage interpretations between the orthopaedic surgeons and the radiologist as well as the reliability of the interpretations among the individual surgeons. Results: Inter-rater kappa values for the attending surgeons and the radiologist averaged 0.526. Inter-rater kappa values for the resident surgeons and the radiologist averaged 0.490 and 0.101. There was significant agreement between the attending surgeons on all 3 occasions (&kgr;=0.764, 0.809, 0.837). The intra-rater reliability among the attending surgeons (&kgr;=0.988, 0.957) and the resident surgeons (&kgr;=0.813, 0.495) showed statistical significance (P<0.0001). Only half of the films had perfect agreement between the radiologist and the surgeons and 28% of the films were interpreted with a difference of 2 or more Risser stages. The radiologist did not interpret any of the films as a Risser 4 or 5 but 21% of the films were interpreted as a 4 or 5 by the orthopaedic surgeons. Conclusions: The scoliosis-screening program utilizes a referral pathway based on the radiologist’s Risser stage interpretation in conjunction with the Cobb angle. The radiologist and the orthopaedic surgeons demonstrated only moderate agreement in their interpretations of Risser stages, resulting in a possible 21% over-referral rate. This study questions the efficacy of using the Risser stage as part of a large metropolitan scoliosis screening program and warrants further investigation.

Two fixation methods for acromioclavicular joint reduction during coracoclavicular ligament reconstruction: a biomechanical analysis.

One specimen from each of six pairs of cadaveric shoulders underwent a semitendinosus coracoclavicular ligament reconstruction with a hook plate used for acromioclavicular joint reduction, while on the other specimen a polydioxanone (PDS) suture braid was utilized. Cyclical loading followed by maximal load-to-failure testing was performed. Displacement during cyclical loading, loads to 50% and 100% displacement, stiffness, and maximal load to failure were determined for all specimens. Results showed that the locking hook plate allowed significantly less displacement of the coracoclavicular interval during cyclical loading (3.41 vs. 9.67 mm, p = .0081) and withstood significantly higher loads before both 50% (225.5 vs. 107.7 N, p = .0197) and 100% displacement (410.6 vs. 240.1 N, p = .0077). The locking hook plate was found to be significantly stiffer than the PDS suture braid (28.2 vs. 18.4 N/mm, p = .0029), but there was no difference in maximal load to failure between the two fixation methods (hook plate, 434.4 N; PDS, 476.7 N; p = .76).

Increasing hip and knee flexion during a drop-jump task reduces tibiofemoral shear and compressive forces: implications for ACL injury prevention training

ABSTRACT Although most ACL injury prevention programmes encourage greater hip and knee flexion during landing, it remains unknown how this technique influences tibiofemoral joint forces. We examined whether a landing strategy utilising greater hip and knee flexion decreases tibiofemoral anterior shear and compression. Twelve healthy women (25.9 ± 3.5 years) performed a drop-jump task before and after a training session (10–15 min) that emphasised greater hip and knee flexion. Peak tibiofemoral anterior shear and compressive forces were calculated using an electromyography (EMG)-driven knee model that incorporated joint kinematics, EMG and participant-specific muscle volumes and patella tendon orientation measured using magnetic resonance imaging (MRI). Participants demonstrated a decrease in peak anterior tibial shear forces (11.1 ± 3.3 vs. 9.6 ± 2.7 N · kg−1; P = 0.008) and peak tibiofemoral compressive forces (68.4 ± 7.6 vs. 62.0 ± 5.5 N · kg−1; P = 0.015) post-training. The decreased peak anterior tibial shear was accompanied by a decrease in the quadriceps anterior shear force, while the decreased peak compressive force was accompanied by decreased ground reaction force and hamstring forces. Our data provide justification for injury prevention programmes that encourage greater hip and knee flexion during landing to reduce tibiofemoral joint loading.

Anatomic, Transepiphyseal Anterior Cruciate Ligament Reconstruction

Introduction Our technique for physeal-sparing, anatomic anterior cruciate ligament (ACL) reconstruction reliably produces femoral tunnels that are of adequate length and that safely avoid the femoral physis without the addition of time-consuming surgical methods or substantial utilization of fluoroscopy. Step 1 Preoperative Planning Obtain radiographs and MRI of the knee as well as an anteroposterior radiograph of the hand (to obtain a bone age). Step 2 Patient Setup Portal Placement and Graft Harvest The affected knee must be able to flex at least 90° with the end of the operative table lowered, in order to properly visualize the anatomy of the ACL femoral footprint. Step 3 Prepare ACL Footprint and Establish Far Anteromedial Portal Maintain soft-tissue remnants at both the femoral and the tibial footprint in order to individualize the anatomy. Step 4 Identify Extra-Articular Landmarks and Prepare Femoral Tunnel Visualize and palpate your previously marked popliteal sulcus and lateral epicondyle; these landmarks are the crucial extra-articular points for establishing a safe femoral tunnel. Step 5 Prepare Tibial Tunnel The tibial tunnel can be safely drilled in a transphyseal manner in skeletally immature patients. Step 6 Fix Graft Use the Arthrex ACL TightRope RT for femoral fixation. Step 7 Postoperative Care As a skeletally immature athlete differs from a more mature athlete in several important ways, alter the postoperative protocol accordingly. Results Our clinical experience has corresponded to our MRI-based findings from our original study14, and we have not observed any physeal or chondral injuries leading to growth disturbances from our femoral tunnels. What to Watch For IndicationsContraindicationsPitfalls & Challenges.

Risk Factors for Manipulation Under Anesthesia and/or Lysis of Adhesions After Anterior Cruciate Ligament Reconstruction

Background: In the currently published literature, a higher risk for developing arthrofibrosis after anterior cruciate ligament (ACL) reconstruction has been reported for female patients, adolescents, early surgery or concomitant procedures, and the use of a patellar tendon autograft. There is a lack of evidence regarding other graft choices or factors. Hypothesis: Multiple risk factors will play a significant role in the development of arthrofibrosis after ACL reconstruction. Specifically, we hypothesized that the risk of manipulation under anesthesia (MUA) and/or lysis of adhesions (LOA) would be affected by graft choice and patient demographic factors. Study Design: Case-control study; Level of evidence, 3. Methods: The charts of all patients who underwent ACL reconstruction over a 10-year period at a single academic institution were queried from an electronic medical record database and reviewed at a minimum of 6 months after ACL reconstruction, with the collection of demographic and surgical data. The relative risk for undergoing MUA and/or LOA was calculated for each analyzed risk factor. Results: A total of 2424 ACL reconstructions were included, with a chart review at a mean of 56.7 months after surgery (range, 7.6-124.0 months). The rate of MUA and/or LOA for arthrofibrosis was 4.5%. A statistically significantly increased relative risk was found for infection (5.45), hematoma requiring evacuation (3.55), ACL reconstruction with meniscal repair (2.83), use of a quadriceps tendon autograft (2.68), age <18 years (2.39), multiple concomitant procedures (1.69), contact injury (1.62), female sex (1.60), and surgery within 28 days of injury (1.53), and a statistically significantly decreased relative risk was found for revision ACL reconstruction (0.30), age >25 years (0.34), and use of a tibialis anterior allograft (0.36). In the multivariate regression model, the use of a quadriceps tendon autograft (P = .00007), infection (P = .00126), and concomitant meniscal repair (P = .00194) were independent risk factors, whereas revision ACL reconstruction (P = .0024) was an independent protective factor. Conclusion: Graft type, infection, concomitant meniscal repair, and primary reconstruction are significant risk factors for undergoing MUA or LOA after ACL reconstruction.

Overview of Surgical Decision Making

Patellofemoral pain and instability are common presenting complaints in the athlete. A prevalence as high as 16.3 in 100 in young female athletes has been reported. Specifically, an incidence of primary patellar dislocation of 5.8 per 100,000 has been noted with this number increasing to as high as 29 per 100,000 in the 10–17-year-old age group [1–3]. These complaints are often more challenging than common, as these symptoms represent a myriad of underlying and often overlapping diagnoses. However, with a careful history, physical exam, and appropriate imaging, the etiology of their pain and/or instability typically can be determined. Utilization of therapists, athletic trainers, and other specialists will aid in successful management outcomes. Although multiple surgical and nonsurgical treatment options exist, appropriate treatment often leads to successful outcomes and a high rate of return to play.