Faculty Bibliography

MicroCT imaging allows for noninvasive microstructural evaluation of mineralized bone tissue, and is essential in studies of small animal models of bone and joint diseases. Automatic segmentation and evaluation of articular surfaces is challenging. Here, we present a novel method to create knee joint surface models, for the evaluation of PTOA-related joint changes in the rat using an atlas-based diffeomorphic registration to automatically isolate bone from surrounding tissues. As validation, two independent raters manually segment datasets and the resulting segmentations were compared to our novel automatic segmentation process. Data were evaluated using label map volumes, overlap metrics, Euclidean distance mapping, and a time trial. Intraclass correlation coefficients were calculated to compare methods, and were greater than 0.90. Total overlap, union overlap, and mean overlap were calculated to compare the automatic and manual methods and ranged from 0.85 to 0.99. A Euclidean distance comparison was also performed and showed no measurable difference between manual and automatic segmentations. Furthermore, our new method was 18 times faster than manual segmentation. Overall, this study describes a reliable, accurate, and automatic segmentation method for mineralized knee structures from microCT images, and will allow for efficient assessment of bony changes in small animal models of PTOA.

In an effort to better restore normal joint function and kinematics, recent emphasis has been placed on surgical techniques that provide a more anatomic reconstruction of the anterior cruciate ligament (ACL). With femoral tunnel placement shown to play a vital role in the biomechanics, stability, and clinical outcomes after ACL reconstruction, approaches that better approximate the ACL's native femoral origin have been adopted. The independent anteromedial portal technique is thought to better position the femoral tunnel within the native ACL footprint and leave the graft more posteroinferior on the wall of the lateral femoral condyle than the more traditional transtibial approach. This article outlines the surgical technique for an anteromedial portal ACL reconstruction with a tibialis anterior allograft fixed with the Mitek Femoral and Tibial Intrafix sheath and screw system (DePuy Synthes, Raynham, MA).

Coronal plane deformity in the adult patient is a complex clinical problem. Once the hip, knee, and ankle joint centers lose collinerarity, the knee is exposed to abnormal loads across its tibiofemoral compartments, leading to early degenerative changes. Malalignment can coexist with arthrosis and ligamentous instability. High tibial osteotomy and distal femoral osteotomy have been useful tools to realign the adult knee. They can be performed along with ligament reconstruction and cartilage restoration procedures with high success rates. Despite novel techniques and fixation methods, principles of deformity correction should be followed to maximize clinical outcomes.

Articular cartilage is a specialized tissue that lines the surface of joints. Injuries to articular cartilage pose challenges due to poor healing potential. Focal cartilage defects are typically the result of high impact or repetitive loads to the articular surface. They tend to occur in the younger, active population and have been shown to cause swelling, pain, and joint dysfunction. Although the natural history of these lesions has never been definitively elucidated in the literature, clinical experience suggests that if left untreated, these lesions will demonstrate an inability to heal and may lead to prolonged increased articular peak stresses, which in turn may lead to pain and significant limitations in the future. The purpose of the present review is to provide the most current treatment options for these injuries and review the literature supporting their use.

The identification of biomarkers has become increasingly important in our fundamental understanding of the molecular basis for disease and subsequently in the advancement of modern medicine. Biomarkers have been identified in a plethora of normal and pathologic conditions and are most often found in blood, tissue, or synovial fluid. Orthopaedic research has more recently focused on biomarkers of cartilage and joint diseases, with an emphasis on understanding the molecular underpinnings of their pathophysiology. This article focuses on the biomarkers identified to date in several select knee pathologies and how further research can contribute to new diagnostic tools and targeted therapeutics.

With the increasing incidence of anterior cruciate ligament (ACL) reconstruction in women and younger patients, the optimal graft choice in the young female patient has become the subject of much debate. This study aimed to evaluate patient-reported outcomes, objective knee stability, complication rates, and the incidence of failure after ACL reconstruction using bone-patellar tendon-bone (BPTB) autograft compared with hamstring (HS) autograft in young female patients. Female patients who underwent primary ACL reconstruction with BPTB or HS autograft between ages 15 and 25 years were identified. Medical records were reviewed for postoperative complications and subsequent procedures on the operative knee. Patients were evaluated with functional surveys, physical examination including Lachman and pivot-shift tests, and arthrometric testing with a KT-1000 arthrometer. There were 37 patients in the BPTB group and 28 patients in the HS group. For patients who did not undergo revision, significant differences were not found in visual analog score (p = 0.94), Lysholm score (p = 0.81), Kujala score (p = 0.85), or Tegner level (p = 0.81). No difference was detected in the rate of return to a level of activity at or above the same level prior to injury (p = 0.31). Significantly more patients in the BPTB group were graded 1a Lachman and negative pivot shift compared with the HS group (p < 0.001). There was a significant difference in mean side-to-side manual maximum arthrometric testing (p < 0.001). There were significantly fewer subsequent procedures and a lower rate of graft failures in the BPTB group. We detected no difference in subjective functional outcomes following ACL reconstruction. However, a higher failure rate in the HS reconstructions and greater laxity by arthrometric testing may indicate increased objective stability with the use of BPTB autograft in the young female patient population. The level of evidence for this article is (level III, retrospective cohort).

BACKGROUND: Patellar tendon rupture is rare in the general population. Typically, failure occurs proximally or at the mid-substance. Distal avulsion from the tibial tubercle in adults is rare and not well described in the orthopedic literature. METHODS: We present the largest series of patients with distal patellar tendon injury with associated multi-ligamentous disruption of the knee. A series of six patients with distal patellar tendon avulsion were identified at a single institution. The cases were reviewed and are presented. RESULTS: Each case of distal patellar tendon rupture was associated with high-energy trauma to the knee. There was multi-ligamentous disruption in all cases, associated tibial plateau fracture in one case, and a compartment syndrome diagnosed in another. We propose that distal patellar tendon avulsion is a distinct pathology of the extensor mechanism in healthy adults. When present, it should prompt clinicians to assess patients for occult knee dislocation, monitor their neurovascular status, and obtain an MRI to evaluate for associated multi-ligamentous injury. CONCLUSION: We propose a modification to the Schenk classification to include extensor mechanism injury to help guide steps of operative intervention.

PURPOSE: To assess screw divergence when inserting an interference screw for a bone-patellar tendon-bone graft using an outside-in technique with a retrograde drill to create the femoral tunnel. METHODS: Ten cadaver specimens underwent anterior cruciate ligament reconstruction with a bone-patellar tendon-bone autograft, with 23-mm-deep tunnels created by a retrograde drill outside-in technique. Drilling angles were based on a previous study that established the optimal angles to recreate the anterior cruciate ligament footprint. To ensure that screw insertion angles matched the angle of socket drilling, a marking pen was used to transpose 2 lines on the skin of the anterior knee corresponding to the drill in both the coronal and axial planes with the knee held at 90 degrees of flexion. The femoral-sided bone plug was affixed with a 7 x 23 mm interference screw through an anteromedial portal. Computed tomography scans were used to calculate coronal and sagittal screw-tunnel divergence. RESULTS: The median screw divergence in the coronal plane was 2.79 degrees , with a range of 1.1 degrees to 17.2 degrees . Of 10 specimens, 8 had no divergence (0 degrees to 5 degrees ), 0 screws were between 5 degrees and 10 degrees , 1 screw was between 10 degrees and 15 degrees , and 1 screw was between 15 degrees and 20 degrees . The 95% confidence interval was 3.73 degrees to 11.69 degrees . No screws had >/=20 degrees of divergence. In the sagittal plane, the median screw divergence was 5.68 degrees , with a range of 1.2 degrees to 18.7 degrees . Five specimens had no divergence (0 degrees to 5 degrees ), 3 screws were between 5 degrees and 10 degrees , 0 screws were between 10 degrees and 15 degrees , and 2 screws were between 15 degrees and 20 degrees of divergence. The 95% confidence interval was 3.73 degrees to 11.69 degrees . No screws had >/=20 degrees of divergence. CONCLUSIONS: The results of this study showed that 80% of screws diverted less than 5 degrees in the coronal plane. In the sagittal plane, only 50% of screws were found to have divergence of 5 degrees or less. No screw in either plane had divergence of greater than or equal to 20 degrees . CLINICAL RELEVANCE: When using a retrograde drill, a skin marking technique is a useful aid in placing interference screws with acceptable angles of divergence when using an inside-out technique.

We retrospectively reviewed the records of 3 patients (3 knees) with a delayed type hypersensitivity reaction following Dermabond exposure after an orthopaedic knee procedure. Delayed hypersensitivity reactions are mediated by CD4+ helper T cells. The use of skin adhesives in place of traditional sutures is increasing in popularity given Dermabond's potential benefits of decreased wound infection rate and better wound approximation. However, hypersensitivity reactions to the cyanoacrylate material in Dermabond have been described. Differentiating hypersensitivity reactions from post-operative infections is important as septic arthritis is a potentially devastating complication. This case series presents the challenge of properly diagnosing and managing hypersensitivity reactions. Consultation with allergists and dermatologists may be appropriate for ascertaining the nature of the surgical site complication and proper management. The recommended management of hypersensitivity-type reactions is a course of topical steroids and infection work up if needed.