Current concepts on trochleoplasty procedures for the surgical treatment of trochlear dysplasia

Trochleoplasty is a surgical procedure, whose goal is to change the abnormal shape of the femoral trochlea in patients with recurrent patellar dislocation. Such surgeries that aim to reshape the articular surface of a bone without damaging it are quite unique in orthopaedic surgery. Although in the beginning, trochleoplasty was reserved for the refractory cases where previous surgery has failed, the last years it became more and more popular because of a better knowledge of anatomy and biomechanics and a greater availability of instruments. The roots of the deepening trochleoplasty could be found in the previous century when the first surgeons tried to directly remove the dysplastic bone with pioneer interventions but with devastating consequences. Since then, multiple procedures have been described and are analysed in this review; each one with its unique features, advantages and pitfalls. Regardless of the technique used, the very recent bibliography presents very encouraging results from the application of trochleoplasty with other procedures in a selected population with severe trochlear dysplasia and recurrent patellar dislocation, in whom the benign neglect of dysplasia would lead to unfavourable results. Level of evidence IV.     

A common epitope between HLA-B27, -B13 and -B37 alloantigens defined by a monoclonal antibody

An anti-HLA-B27 monoclonal antibody produced by the hybridoma technique is described. This BD.7 reagent is a cytotoxic IgM antibody. Its reactivity was studied by lymphocytotoxicity tests, indirect immunofluorescence tests and biochemical analysis against an extensive panel of peripheral blood mononuclear cells. All HLA-B27 positive samples, either from normal subjects or from patients with Ankylosing Spondylitis, were recognized by this reagent. Moreover, a cross-reaction was observed with HLA-B13 cells, and a new unexpected reaction with all HLA-B37 cell suspensions. The interest of such a reagent is discussed.     

The weight-bearing knee after anterior cruciate ligament rupture

Unilateral weight bearing was simulated on 12 cadaver knees to quantitate anterior tibial translation (ATT) after anterior cruciate ligament (ACL) transection and to asses the role of the posteromedial structure and the hamstrings in controlling laxity. With the ACL intact, ATT was 3.5±2.8 mm in extension and 4.3±3.6 mm at 60° flexion. After sectioning the ACL, ATT was 6.5±4.7 mm in extension and 17.5±10 mm at 60° flexion (P=0.001). Applying a force in the hamstrings was unable to correct the pathological ATT observed after ACL section. Partial medial meniscectomy did not increase ATT after the ACL section. Disinsertion of the posterior horn of the medial meniscus and total medial meniscectomy increased ATT significantly compared to isolated ACL section. After ACL transection, sectioning the meniscotibial fibers or posteromedial capsule significantly increased ATT (6.5±0.5 mm in extension). Section of the postero-oblique ligament or popliteus tendon had no effect on ATT.     

Extra-articular tenodesis for anterior cruciate ligament rupture in amateur skiers.

Thirty one amateur skiers with 33 knees which had had a symptomatic chronic rupture of the anterior cruciate ligament (ACL) treated with the Lemaire operation were reviewed retrospectively at an average of 4.5 years. Of the patients 23 were women. The operation failed to control symptoms in 17 out of the 33 knees. However the operation did control symptoms in 13 out of 19 knees in patients over 35 years old, compared with only three out of 14 knees in patients under 35 years old. Clinical and objective testing however showed that most knees were still unstable. Despite this 21 patients continued skiing. One patient with a successful result switched to playing tennis. Five patients gave up all sports. Four further patients, all under 35 years old, returned to skiing after an additional intra-articular reconstruction of the anterior cruciate ligament. An isolated extra-articular procedure in amateur skiers under 35 years old with symptomatic chronic ACL rupture is not recommended. They need at least an intra-articular reconstruction to control their symptoms and to stabilize the knee.     

An anatomical and radiological study of the femoropatellar articulation

Summary An analytical study was made of 30 knees by dissection, 200 by conventional radiology, 120 by CT scans, and of 2,400 pathological knees by conventional radiology, and 900 by CT. The radiological and scanning methods most used for a study of the femoropatellar articulation are described and the normal values of each feature determined by a computer study. The femoral trochlea and its shape are very important for the stability of the patella. The normal and pathological types of trochlea are described. This study established a number of anatomical factors which influence patellar stability, and form a basis for proposing the correction of anatomical anomalies in the treatment of instability of the joint.

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Etude radio-anatomique de l'articulation fémoro-patellaire

Résumé Les auteurs ont analysé 30 genoux par dissection, une série en radiologie conventionnelle de 200 genoux témoins, une série de 120 tomodensitométries de genoux témoins, une population pathologique de 2 400 genoux en radiologie conventionnelle et de 900 genoux en tomodensitométrie. Les méthodes radiologiques et scannographiques les plus utiles pour analyser l'articulation fémoro-patellaire sont décrites et les valeurs normales de chaque facteur précisées à partir d'une étude informatique. la trochlée fémorale et sa morphologie sont très importantes pour stabiliser la rotule. Des types de trochlées normales et pathologiques sont décrits. Cette étude permet d'établir un certain nombre de facteurs anatomiques influençant la stabilité patellaire et, en s'appuyant sur une étude parallèle, de proposer la correction des anomalies anatomiques dans le traitement des instabilités patellaires.

     

Evaluation of anterior knee laxity on MRI

Purpose

Evaluation of the ACL and anterior knee laxity on MR during anterior tibial translation.

Patients and methods

Three groups were identified based on clinical and arthrometric (KT-1000) data: normal ACL (n = 12), complete tear (n = 10) and partial tear (n = 20). MRI was performed without and with anterior tibial translation (pneumatic device) with morphological and laximetric analysis: drawer tests and dynamic evaluation of ligamentous tension.

Results

Intra- and inter-observer reproducibility was excellent, correlated to arthrometric data and clinical tests (Lachman, pivot shift). The difference between the drawer signs of normal subjects and patients with ACL tear was significant for a threshold value of 1,1 mm for the anterior drawer (sensitivity: 93,33%, specificity: 91,7%) and 2,8 mm for the posterior drawer (sensitivity: 86,7%, specificity: 100%). Dynamic evaluation of ligamentous tension was also reproducible, statistically correlated to the MR drawer tests and reliable for the diagnosis of ACL lesions. In this preliminary study, the distinction between complete and partial ACL tears could not be detected.

Conclusion

Anterior cruciate ligament function can be demonstrated on MR. The predictive value of this morphological and functional association should be determined in the management of patients with partial tears.     

The intra- and inter-observer reliability of the physical examination methods used to assess patients with patellofemoral joint instability

BackgroundAn accurate physical examination of patients with patellar instability is an important aspect of the diagnosis and treatment. While previous studies have assessed the diagnostic accuracy of such physical examination tests, little has been undertaken to assess the inter- and intra-tester reliability of such techniques. The purpose of this study was to determine the inter- and intra-tester reliability of the physical examination tests used for patients with patellar instability.MethodsFive patients (10 knees) with bilateral recurrent patellar instability were assessed by five members of the International Patellofemoral Study Group. Each surgeon assessed each patient twice using 18 reported physical examination tests. The inter- and intra-observer reliability was assessed using weighted Kappa statistics with 95% confidence intervals.ResultsThe findings of the study suggested that there were very poor inter-observer reliability for the majority of the physical tests, with only the assessments of patellofemoral crepitus, foot arch position and the J-sign presenting with fair to moderate agreement respectively. The intra-observer reliability indicated largely moderate to substantial agreement between the first and second tests performed by each assessor, with the greatest agreement seen for the assessment of tibial torsion, popliteal angle and the Bassett's sign.ConclusionsFor the common physical examination tests used in the management of patients with patellar instability inter-observer reliability is poor, while intra-observer reliability is moderate. Standardization of physical exam assessments and further study of these results among different clinicians and more divergent patient groups is indicated.     

Imaging in Patellofemoral Instability: An Abnormality-based Approach

Imaging in patellofemoral instability confirms the diagnosis and guides treatment. It is essential to the accurate diagnosis of the root causes and their adequate treatment. A structured approach must be used to identify the factors causing instability, and more than 1 imaging modality may provide similar information. This article revises the acute findings and the abnormalities present in the acute and the chronic settings.     

Kniegelenknahe Flexions- und Extensionsosteotomien beim Erwachsenen

Zusammenfassung Kniegelenknahe Flexions- oder Extensionsosteotomien sind seltene Eingriffe. Die Indikation zur operativen Behandlung eines solchen Kniegelenks ist abhängig von der funktionellen Beeinträchtigung und hierbei insbesondere der Instabilität des Kniegelenks bei Belastung (seltener wegen Schmerzen), dem klinischen und dem radiologischen Befund. Dem knöchernen Eingriff zur Korrektur der Deformität ist in einigen Fällen eine periphere oder zentrale Bandplastik des Kniegelenks hinzuzufügen.Zur präoperativen Abklärung ist eine eingehende röntgenologische Abklärung unabdingbar. Hier muss eine beginnende Arthrose ausgeschlossen und die Neigung des Tibiaplateaus bestimmt werden. Darüber hinaus führen wir routinemäßig gehaltene Aufnahmen zur Bestimmung der vorderen und hinteren Schublade durch. Im Falle einer begleitenden vorderen oder hinteren Kreuzbandruptur sollte die Notwendigkeit einer begleitenden Bandplastik mit diskutiert werden.Aus dem Französischen übersetzt von Priv.-Doz. Dr. R. Seil, Orthopädische Universitätsklinik Homburg/Saar.