Idiopathic hip chondrolysis: a case report of a Caucasian HLA-B27 positive adolescent with a history of long walking.

Idiopathic hip chondrolysis is a rare disorder, the pathophysiology of which has not been fully elucidated. Several theories have been proposed regarding the cause of the disease with some of them involving autoimmune-mediated cartilage destruction. There are several similar features between idiopathic hip chondrolysis and rheumatologic diseases such as juvenile idiopathic arthritis, so whether these two disorders are different or not is still debatable. This case report aims to help comprehending this complex disorder by presenting a case of idiopathic hip chondrolysis with apparent risk factors, such as repetitive microtrauma and presence of HLA-B27 antigens. A 15-year-old HLA-B27 positive male presented with idiopathic hip chondrolysis after excessive walking. Initial treatment consisted of medications including corticosteroids, protected weight bearing and surgical soft tissue release. After failure of all these modalities in restoring the decreased range of motion of the hip, a course of a TNF-inhibitor, etanercept was tried. Alleviation of pain achieved early in the treatment period, but range of motion remained mainly unchanged. Although there was a brief improvement of stiffness for a short period after surgery which lasted for about 3 months, stiffness came back afterwards. Administration of a TNF inhibitor in the following period significantly improved his range of motion. The presence of laboratory findings indicating an autoimmune tendency in this patient supports the hypothesis of susceptibility of these patients to autoimmune reactions, while excessive walking was an apparent trigger factor. In future, traditional treatments may be abandoned in favor of novel medications targeting immunologic pathways.

Proximal screws placement in intertrochanteric fractures treated with external fixation: comparison of two different techniques.

BACKGROUND: To compare two different techniques of proximal pin placement for the treatment of intertrochanteric fractures in elderly patients utilizing the Orthofix Pertrochanteric Fixator. METHODS: Seventy elderly high-risk patients with an average age of 81 years were treated surgically for intertrochanteric fracture, resulting from a low energy trauma. Patients were randomly divided in two groups regarding to the proximal pin placement technique. In Group A the proximal pins were inserted in a convergent way, while in Group B were inserted in parallel. RESULTS: All fractures healed uneventfully after a mean time of 98 days. The fixator was well accepted and no patient had significant difficulties while sitting or lying. The mean VAS score was 5.4 in group A and 5.7 in group B. At 12 months after surgery, in group A the average Harris Hip Score and the Palmer and Parker mobility score was 67 and 5.8, respectively. In group B, the average Harris Hip Score and the Palmer and Parker mobility score was 62 and 5.6, respectively. No statistically significant difference was found regarding the functional outcome. The mean radiographic exposure during pin insertion in Group A and Group B was 15 and 6 seconds, respectively. The difference between the two groups, regarding the radiographic exposure, was found to be significant. CONCLUSION: Proximal screw placement in a parallel way is simple, with significant less radiation exposure and shorter intraoperative duration. In addition, fixation stability is equal compared to convergent pin placement.

Simultaneous bicompartmental bucket-handle meniscal tears with intact anterior cruciate ligament: a case report.

INTRODUCTION: Bucket handle tear of the menisci is a common type of lesion resulting from injury to the knee joint. Bucket handle injury of both menisci in almost all cases is associated with a lesion to either the anterior or the posterior cruciate ligament of the knee joint. We describe a case of acute bucket-handle tear of the medial and lateral menisci with intact anterior and posterior cruciate ligaments in a dancer. To the best of our knowledge, there are no previous reports of this type of injury in the literature. CASE PRESENTATION: A 28-year-old Caucasian Greek woman presented to the emergency department after sustaining an injury to her right knee during dancing. An MRI evaluation demonstrated tears in both menisci of the right knee, while the anterior and posterior cruciate ligaments were found to be intact. A partial medial and lateral meniscectomy was then performed. At a follow-up examination six months after her injury, clinical tests demonstrated that our patient's right knee was stable, had a full range of motion and had no tenderness. She was satisfied with the outcome of the operation and returned to her pre-injury activities. CONCLUSION: We present the first case in the literature that describes a combined bucket-handle injury of both the medial and lateral menisci with an intact anterior cruciate ligament. The clinical examination of the anterior cruciate ligament was unremarkable, with no signs of deficiency or rupture. The posterior cruciate ligament was also intact. On magnetic resonance imaging, the ligaments were visualised as intact in all their length. These findings were confirmed by arthroscopic evaluation.

Advances in articular cartilage repair.

Many joint and systemic disorders may lead to cartilage defects. Partial thickness defects of the articular cartilage do not have healing potential. When the lesion reaches the subchondral bone, spontaneous healing may be observed, but consists of fibrocartilaginous tissue. The main efforts for cartilage repair are targeted at filling of the cartilage defect with a tissue that possesses the same mechanical properties with hyaline cartilage and the consolidation of this tissue with the native articular cartilage. There are various arthroscopic techniques and although they provide pain relief, they do not restore the damaged cartilage. Osteochondral transplantation is more effective in dealing with small or medium size full thickness defects, but further efforts are required in order to reduce the donor site morbidity, marginal necrosis and partial covering of the defect.

The effect of initial graft tension on the biomechanical properties of a healing ACL replacement graft: a study in goats.

While a number of in vitro studies have shown that the tension on an anterior cruciate ligament (ACL) replacement graft at the time of fixation has an affect on joint stability, most in vivo studies have reported little or no long-term difference in outcome. The objectives of this study were to (1) establish a large animal model in which differences in knee stability are present at time-zero after ACL reconstruction with grafts fixed at a low (5 N) and high (35 N) initial tension and to (2) quantitatively determine if these initial effects remain after six weeks of healing and if the tensile properties of an ACL replacement graft are influenced by initial graft tension. Seventeen skeletally mature female Saanan breed goats were used. Using the robotic/UFS testing system, the knee kinematics and in situ forces in the replacement graft in response to an externally applied 67 N anterior-posterior (A-P) tibial load were evaluated at time-zero and after six weeks of healing. Afterward, the femur-ACL graft-tibia complexes (FGTCs) from the six-week group were tested under uniaxial tension so that the stress relaxation and structural properties of the FGTC were obtained. At time-zero, knees fixed with a high initial graft tension could better reproduce the A-P translation of the intact knee in response to the 67 N A-P tibial load. Further, in situ forces in these grafts were also closer to those in the intact ACL under the same external loading condition. After six weeks of healing, the A-P translation of the knee and in situ forces in the replacement grafts became similar for the low and high tension groups, while both were significantly different from controls. Further, the percentage of stress relaxation as well as the stiffness, ultimate load at failure, ultimate elongation at failure, and energy absorbed of the FGTCs for both reconstruction groups were not significantly different from each other, but were significantly different from controls. These results demonstrate that while the high initial graft tension could better replicate the normal knee kinematics at time-zero, these effects may diminish during the early graft healing process.

A biomechanical and histological evaluation of the structure and function of the healing medial collateral ligament in a goat model.

This study evaluated the healing process of an isolated medial collateral ligament (MCL) rupture at 12 weeks in a goat model. Using a robotic/UFS testing system, knee kinematics in multiple degrees of freedom and in situ forces in the healing MCL in response to (1) a 67-N anterior tibial load and (2) a 5-Nm valgus moment were evaluated as a function of angles of knee flexion. Then a uniaxial tensile test of femur-MCL-tibia complexes (FMTCs) was preformed to obtain the structural properties of the FMTC and mechanical properties of the healing MCL substance. The histological appearance of the healing MCL was also examined for collagen and cell organization. The anterior tibial translation in response to a 67-N anterior tibial load was found to range from 1.9 to 2.4 mm, which was not significantly different from the sham-operated, contralateral control knee. In response to a 5-Nm valgus moment, however, MCL injury caused a 40% or more increase in valgus rotations over sham-operated controls for all angles of knee flexion tested. The magnitudes of the in situ forces in the healing MCLs for neither external loading conditions differed from sham-operated controls. For the structural properties of the healing FMTC, the stiffness returned to sham-operated control levels, but ultimate load at failure remained 60% of sham-operated control values. In terms of mechanical properties of the healing MCL, its tangent modulus and stress at failure were only 40% of sham-operated control values. Histologically, the collagen and cell organization at the femoral and tibial insertions as well as the midsubstance remained disorganized. Comparing these data to those previously reported at 6 weeks, there was a marked improvement in the in situ forces in the healing MCL and of the stiffness of the FMTC. Also, the data obtained for the goat model revealed a faster healing process than those for the rabbit model. These findings suggest that greater post-injury activity levels may render the goat to be a better animal model for studying the healing process of the MCL.

Three-dimensional tibiofemoral kinematics of the anterior cruciate ligament-deficient and reconstructed knee during walking.

BACKGROUND: It is possible that gait abnormalities may play a role in the pathogenesis of meniscal or chondral injury as well as osteoarthritis of the knee in patients with anterior cruciate ligament deficiency. HYPOTHESIS: The three-dimensional kinematics of anterior cruciate ligament-deficient knees are changed even during low-stress activities, such as walking, but can be restored by reconstruction. STUDY DESIGN: Case control study. METHODS: Using a three-dimensional optoelectronic gait analysis system, we examined 13 patients with anterior cruciate ligament-deficient knees, 21 patients with anterior cruciate ligament-reconstructed knees, and 10 control subjects with uninjured knees during walking. RESULTS: Normal patterns of knee flexion-extension, abduction-adduction, and internal-external rotation during the gait cycle were maintained by all subjects. A significant difference in tibial rotation angle during the initial swing phase was found in anterior cruciate ligament-deficient knees compared with reconstructed and control knees. The patients with anterior cruciate ligament-deficient knees rotated the tibia internally during the initial swing phase, whereas the others rotated externally. CONCLUSIONS: Patients with anterior cruciate ligament-deficient knees experienced repeated episodes of rotational instability during walking, whereas patients with reconstruction experienced tibial rotation that is closer to normal. CLINICAL RELEVANCE: Repeated episodes of knee rotational instability may play a role in the development of pathologic knee conditions.

The diagnostic dilemma created by osteoid osteoma that presents as knee pain.

PURPOSE: Osteoid osteoma is a rare benign bone lesion with a high incidence in adolescents and young people. The objective of our study was to illustrate the difficulties in diagnosis of osteoid osteoma in patients presenting with atypical knee pain. TYPE OF STUDY: Retrospective case series. METHODS: In 10 patients who presented to our department with atypical knee pain between 1984 and 1999, the diagnosis of an osteoid osteoma was delayed. Retrospective review of these 10 cases was performed using interviews and re-evaluation of medical histories, radiographs, computed tomography (CT) scans, isotope bone scan, and magnetic resonance imaging (MRI). RESULTS: Initial radiographs showed features of osteiod osteoma in only 2 cases. In addition, in 1 case, not only initial but also repeated radiographs of the knee joint were still normal 10 months after the delineation of the nidus using MRI. Four unnecessary arthroscopies were performed on 4 of the 10 patients and the final diagnosis was established using MRI, CT, and isotope bone scan. The mean time interval between arthroscopy and osteiod osteoma diagnosis was 11.5 months. CONCLUSIONS: Osteoid osteoma must be included in the differential diagnosis of persistent unexplained knee pain, especially when objective findings of the knee are vague. The presence of the lesion juxta-articular to the knee joint or in the midshaft or upper end of the femur may be referred as pain to a nearby joint. Plain radiographs have a low diagnostic value in the detection of the lesion whereas isotope bone scan and MRI are reliable imaging techniques. The evaluation of the ipsilateral hip joint should not be overlooked.