Osteochondritis Dissecans of the Knee: An Interrater Reliability Study of Magnetic Resonance Imaging Characteristics.

BACKGROUND: Imaging characteristics of osteochondritis dissecans (OCD) lesions quantified by magnetic resonance imaging (MRI) are often used to inform treatment and prognosis. However, the interrater reliability of clinician-driven MRI-based assessment of OCD lesions is not well documented. PURPOSE: To determine the interrater reliability of several historical and novel MRI-derived characteristics of OCD of the knee in children. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 3. METHODS: A total of 42 OCD lesions were evaluated by 10 fellowship-trained orthopaedic surgeons using 31 different MRI characteristics, characterizing lesion size and location, condylar size, cartilage status, the interface between parent and progeny bone, and features of both the parent and the progeny bone. Interrater reliability was determined via intraclass correlation coefficients (ICCs) with 2-way random modeling, Fleiss kappa, or Krippendorff alpha as appropriate for each variable. RESULTS: Raters were reliable when the lesion was measured in the coronal plane (ICC, 0.77). Almost perfect agreement was achieved for condylar size (ICC, 0.93), substantial agreement for physeal patency (ICC, 0.79), and moderate agreement for joint effusion (ICC, 0.56) and cartilage status (ICC, 0.50). Overall, raters showed significant variability regarding interface characteristics (ICC, 0.25), progeny (ICC range, 0.03 to 0.62), and parent bone measurements and qualities (ICC range, -0.02 to 0.65), with reliability being moderate at best for these measurements. CONCLUSION: This multicenter study determined the interrater reliability of MRI characteristics of OCD lesions in children. Although several measurements provided acceptable reliability, many MRI features of OCD that inform treatment decisions were unreliable. Further work will be needed to refine the unreliable characteristics and to assess the ability of those reliable characteristics to predict clinical lesion instability and prognosis.

Osteochondral Injuries of the Knee in Pediatric Patients.

Osteochondral injuries in pediatric patients may occur as a result of a traumatic injury or secondary to an osteochondritis dissecans (OCD) lesion. Lateral patella dislocation is a common traumatic cause of osteochondral injury that typically occurs at the medial facet of the patella or at the lateral aspect of the distal femur. Multiple theories have been proposed for the cause of an OCD lesion in the knee, including trauma or repetitive microtrauma, local vascular insufficiency, and family history. The most "classic" location for OCD lesions of the knee is the lateral aspect of the medial femoral condyle of the distal femur. Multiple treatment options are available for both traumatic osteochondral injuries and OCD lesions, with important determining factors of treatment being skeletal maturity of the patient, instability of the fragment, lesion location, and size of the lesion. Nonsurgical management is appropriate in some situations. Surgical options range from simple fragment excision to internal fixation of the fracture fragment to more complex cartilage restoration or replacement procedures. This special focus section will discuss the diagnosis and treatment options for traumatic osteochondral knee injuries, including the subset secondary to juvenile OCD lesions.

How Many Patients Who Have a Clubfoot Treated Using the Ponseti Method are Likely to Undergo a Tendon Transfer?

BACKGROUND: The Ponseti method has become the standard of care for the treatment of idiopathic clubfoot. A commonly reported problem encountered with this technique is a relapsed deformity that is sometimes treated in patients older than 2.5 years by an anterior tibial tendon transfer (ATTT) to the third cuneiform. Presently, there is insufficient information to properly counsel families whose infants are beginning Ponseti treatment on the probability of needing later tendon transfer surgery. METHODS: All idiopathic clubfoot patients seen at the authors' institution during the study period who met the inclusion criteria and who were followed for >2.5 years were included (N=137 patients). Kaplan-Meier Survival analysis was used to determine the probability of survival without the need for ATTT surgery. In addition, the influence of patient characteristics, socioeconomic variables, and treatment variables on need for surgery was calculated. RESULTS: On the basis of the survivorship analysis, the probability of undergoing an ATTT remained below 5% for all patients at 3 years of age, but exceeded 15% by 4 years of age, increasing steadily afterwards such that by 6 years of age, the probability of undergoing an ATTT reached 29% of all patients. Overall, controlling for all other variables in the analysis, parent-reported adherence with bracing reduced the odds of undergoing surgery by 6.88 times, compared with parent-reported nonadherence (P<0.01). CONCLUSIONS: This is the first study to report the probability of undergoing ATTT surgery as a function of age using survivorship analysis following Ponseti clubfoot treatment. Although the overall probability reached 29% at 6 years, this was significantly reduced by compliance with bracing. This information may be useful to the clinician when counseling families at the start of treatment. LEVEL OF EVIDENCE: Level III-theraputic.

Management of Osteochondritis Dissecans Lesions of the Knee, Elbow and Ankle.

Although osteochondritis dissecans (OCD) has been a recognized condition for more than 100 years, our understanding of the etiology, natural history, and treatment remains poorly characterized. OCD most commonly affects the knee, followed by the elbow and ankle. Adolescents and young adults are most commonly affected. Patients present with vague, often intermittent symptoms and generally have no history of acute injury. Although diagnosis can be made with plain radiographs, treatment decisions are generally based on MRI. Skeletal maturity and stability of the OCD lesion determine treatment. Treatments range from immobilization and activity restriction to operative therapies. Clinical indications are discussed.

Strength of Thoracic Spine Under Simulated Direct Vertebral Rotation: A Biomechanical Study.

BACKGROUND: Direct vertebral rotation (DVR) has gained increasing popularity for deformity correction surgery. Despite large moments applied intraoperatively during deformity correction and failure reports including screw plow, aortic abutment, and pedicle fracture, to our knowledge, the strength of thoracic spines has been unknown. Moreover, the rotational response of thoracic spines under such large torques has been unknown. PURPOSE: Simulate DVR surgical conditions to measure torsion to failure on thoracic spines and assess surgical forces. STUDY DESIGN: Biomechanical simulation using cadaver spines. METHODS: Fresh-frozen thoracic spines (n = 11) were evaluated using radiographs, magnetic resonance imaging (MRI) and dual-energy x-ray absorptiometry. An apparatus simulating DVR was attached to pedicle screws at T7-T10 and transmitted torsion to the spine. T11-T12 were potted and rigidly attached to the frame. Strain gages measured the simulated surgical forces to rotate spines. Torsional load was increased incrementally till failure at T10-T11. Torsion to failure at T10-T11 and corresponding forces were obtained. RESULTS: The T10-T11 moment at failure was 33.3 ± 12.1 Nm (range = 13.7-54.7 Nm). The mean applied force to produce failure was 151.7 ± 33.1 N (range = 109.6-202.7 N), at a distance of approximately 22 cm where surgeons would typically apply direct vertebral rotation forces. Mean right rotation at T10-T11 was 11.6°±5.6°. The failure moment was significantly correlated with bone mineral density (Pearson coefficient 0.61, p = .047). Failure moment also positively correlated with radiographic degeneration grade (Spearman rho > 0.662, p < .04) and MRI degeneration grade (Spearman rho = 0.742, p = .01). CONCLUSION: The present study indicated that with the advantage of lever arms provided with DVR techniques, relatively small surgical forces, <200 N, can produce large moments that cause irreversible injury. Although further studies are required to establish the safety of surgical deformity correction surgeries, the present study provides a first step in the quantification of thoracic spine strength.

Surgical approach to the posteromedial corner: indications, technique, outcomes.

Injuries to the medial side of the knee can occur in isolation or in conjunction with multiple other ligaments about the knee. In addition, medial knee injuries can involve isolated injury to the medial collateral ligament or include the posteromedial structures of the knee. Treatment strategies differ greatly depending on injury pattern. In order to select an appropriate treatment strategy, one must accurately diagnose the injury pattern based on clinical examination and the use of appropriate imaging studies. The fundamental basis for diagnosis of a medial sided knee injury stems from understanding the static and dynamic stabilizing structures that compose the medial side of the knee. It is our aim to define the anatomic roles of medial sided structures, their importance in protecting the biomechanical stability of the knee, as well as provide indications and our preferred procedures for surgical management of these complex injuries.

Current concepts in knee dislocations: PCL, ACL, and medial sided injuries.

Dislocations resulting in multiligament knee injuries are challenging to treat and diagnose. With proper diagnosis and anatomic reconstruction techniques, patients can have successful outcomes. This article describes the senior author's (J.P.S.'s) preferred reconstruction techniques, timing for surgery, and rehabilitation techniques for injuries involving the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), and posteromedial corner (PMC). We prefer to address these injuries in a staged fashion. The PCL, PMC, and any additional meniscal pathology are addressed in the index procedure. The ACL is reconstructed approximately 6 weeks later to ensure that acceptable range of motion has been regained. Staging procedures also allow time to maximize rehabilitation protocols for both the PCL and the ACL.