Combination of the medial patellofemoral ligament reconstruction with the quasi-anatomic technique, tibial tuberosity osteotomy, lateral retinaculum release and mosaicplasty produces satisfactory results for patients with patello-femoral instability. 2-Year follow-up.

INTRODUCTION: This study aimed to evaluate the effectiveness and safety of a combined surgical approach for treating complex patellofemoral instability. This approach combines four procedures: medial patellofemoral ligament (MPFL) reconstruction with the quasi-anatomic technique, lateral retinaculum release, anteromedialization and distalization of tibial tuberosity and patellar/femoral mosaicplasty. MATERIAL AND METHODS: Between August and November 2021, we enrolled 27 patients in the study (21 females, 6 males, average age 28.6 years). All with patella alta, recurrent patellar instability, severe cartilage focal damage, and increased tibial tubercle-trochlear groove distance. All underwent the combined procedure during this period. We assessed their pain and functional scores before surgery and at 6, 12, and 24 months after surgery using standardized scoring systems. RESULTS: Patients initially reported significant pain and functional limitations. However, at 24 months, their pain scores significantly reduced, averaging 1.5 compared to 8.2 pre-surgery. Similarly, their functional scores substantially improved, with Lysholm, Tegner, Kujala, BPII scores reaching 87.44, 8.44, 90.03, 86.07 compared to 56.4, 3.7, 42.48, 23 pre-surgery, respectively. Importantly, no cases of recurrent instability occurred, and 96.3% of patients reported complete satisfaction. CONCLUSIONS: This combined surgical approach has a high rate of success for patients with patella alta, recurrent lateral patellar instability, severe focal chondral lesions, and increased TT-TG distance. Moreover, 26 out of 27 patients (96.3%) reported total satisfaction. Therefore, we conclude that although this procedure combination is not simple, it is a safe, reproducible, and alleviates pain at 24 months postoperatively, and significantly improves functional scores.

Allograft reconstruction of the medial patellofemoral complex in skeletally immature patients: a technical note.

Patellofemoral instability (PFI) is a common disorder in children and adolescents. Surgical stabilization of the patella poses challenges in skeletally immature patients due to anatomical peculiarities at this stage, leading to the absence of an established standard reconstruction technique. Recently, there has been a notable interest in the medial patellofemoral complex (MPFC), encompassing the medial patellofemoral ligament (MPFL) and the medial quadriceps tendon femoral ligament (MQTFL), owing to their role in restricting lateral patellar displacement. This paper aims to describe the surgical technique employed by the author for reconstructing the medial patellofemoral complex with allograft in skeletally immature patients with patellofemoral instability. Study design: surgical technique.

La inestabilidad patelofemoral (PFI) es un trastorno común en niños y adolescentes. La estabilización quirúrgica de la rótula plantea desafíos en pacientes esqueléticamente inmaduros debido a peculiaridades anatómicas en esta etapa, lo que lleva a la ausencia de una técnica de reconstrucción estándar establecida. Recientemente, ha habido un interés notable en el complejo femororrotuliano medial (MPFC), que abarca el ligamento femororrotuliano medial (MPFL) y el ligamento femoral del tendón del cuádriceps medial (MQTFL), debido a su papel en la restricción del desplazamiento rotuliano lateral. Este artículo tiene como objetivo describir la técnica quirúrgica empleada por el autor para reconstruir el complejo femororrotuliano medial con aloinjerto en pacientes esqueléticamente inmaduros con inestabilidad femororrotuliana. Diseño del estudio: técnica quirúrgica.

Corrección de la altura patelar en inestabilidad rotuliana / Correction of patellar height in patellofemoral instability

El manejo de la inestabilidad patelofemoral se basa en una adecuada evaluación de alteraciones anatómicas predisponentes. Patela alta es una de las causas más importantes de inestabilidad objetiva. La alteración biomecánica que ésta produce puede conducir a luxación patelar recurrente, dolor y cambios degenerativos focales. El examen físico es fundamental en la toma de decisiones. La evaluación imagenológica ha evolucionado desde métodos basados en radiografía hacia mediciones en resonancia magnética, que permiten una orientación más acabada de la relación existente entre la rótula y la tróclea femoral. El tratamiento se fundamenta en la corrección selectiva de los factores causales, donde la osteotomía de descenso de la tuberosidad anterior de la tibia y la reconstrucción del ligamento patelofemoral medial son herramientas que deben considerarse racionalmente. Este artículo realiza una revisión de la literatura, otorgando los fundamentos quirúrgicos que explican la importancia del tratamiento específico de patela alta en inestabilidad rotuliana.

Patellofemoral instability management is based on a thorough evaluation of predisposing anatomical factors. Patella alta is one of the utmost causes of objective instability. As a result, biomechanical disturbance can lead to recurrent patellar instability, pain, and focal degenerative changes. Physical examination is paramount in decision making. Imaging evaluation has evolved from X-rays based methods to magnetic resonance measurements, which allows a more accurate assessment of the patellotrochlear relationship. Treatment is based on a selective risk factors correction, where tibial tubercle distalization osteotomy and medial patellofemoral ligament reconstruction must be considered altogether. This article reviews the surgical rationale of patella alta treatment in patellofemoral instability.

Valor de la distancia entre la tuberosidad anterior de la tibia y el surco intercondíleo en la inestabilidad patelofemoral / Value from the tibial-tuberosity to trochlear groove distance in the patellofemoral instability

La inestabilidad patelofemoral es una entidad que afecta principalmente a adolescentes y adultos jóvenes. En su diagnóstico se consideran elementos clínicos e imagenológicos, en especial para medir la distancia entre la tuberosidad anterior de la tibia y el surco intercondíleo, que permite la selección de la técnica quirúrgica en cada paciente, en específico la transferencia de la tuberosidad anterior de la tibia. En este artículo se exponen brevemente algunos aspectos de interés sobre el tema: métodos imagenológicos empleados en estos pacientes (radiografía simple, tomografía axial computarizada, imagen por resonancia magnética) y valores de referencia considerados como normales; también se describe por pasos cómo medir la distancia entre la tuberosidad anterior de la tibia y el surco intercondíleo.

The patellofemoral instability is an entity that mainly affects adolescents and young adults. In its diagnosis clinical and imaging elements are considered, especially to measure the tibial-tuberosity to trochlear groove distance that allows the selection of the surgical technique in each patient, in specific the transfer of the tibial-tuberosity. In this work some aspects of interest on the topic are shortly exposed: the imaging methods used in these patients (simple x-rays, computerized axial tomography, magnetic resonance imaging) and the reference values considered as normal; it is also described step by step how to measure the tibial-tuberosity to trochlear groove distance.

In Kinematically Aligned Total Knee Arthroplasty, Failure to Recreate Native Tibial Alignment Is Associated With Early Revision.

BACKGROUND: The goal of kinematically aligned (KA) total knee arthroplasty (TKA) is to restore native knee anatomy. However, there are concerns about patellofemoral tracking problems with this technique that lead to early revision. We measured the differences between preoperative anatomic alignment and postoperative component alignment in a consecutive series of KA TKA and evaluated the association between alignment changes and the likelihood of early revision. METHODS: The charts of 219 patients who underwent 275 KA TKA procedures were reviewed. Preoperative anatomic alignment and postoperative tibial and femoral component alignment were measured radiographically. The difference in component alignment compared with preoperative anatomic alignment was compared between patients who underwent aseptic revision and those who did not at a minimum of 12 months of follow-up. Receiver operating characteristic curves were created for statistically significant variables, and the Youden index was used to determine optimal alignment thresholds with regard to likelihood of revision surgery. RESULTS: Change in tibial component alignment compared with native alignment was greater (P = .005) in the revision group (5.0° ± 3.7° of increased varus compared with preoperative anatomic tibial angle) than in the nonrevision group (1.3° ± 4.2° of increased varus). The Youden index indicated that increasing tibial varus by >2.2° or more is associated with increased likelihood of revision. Preoperative anatomic alignment and change in femoral alignment and overall joint alignment (ie, Q angle) were not associated with increased likelihood of revision. CONCLUSION: Small increases in tibial component varus compared with native alignment are associated with early aseptic revision in patients undergoing KA TKA.

Clinical and Radiologic Outcomes of the Surgical Treatment of Patellofemoral Instability in Children with Down Syndrome and Dislocated Patella: Case Series.

INTRODUCTION: We attended three skeletally immature patients with Down syndrome (DS) with complaints of severe patellofemoral instability and dislocated patella (preoperatively, Dugdale classification IV or V), in addition to low functional capacity, with falls during gait. The technique (lateral release, medial capsulectomy, reconstruction of the medial patellofemoral ligament (MPFL) with the patellar ligament and associated techniques, and some knees) and results in three children with DS and bilaterally dislocated patella were revealed. CASE REPORT: Our minimum follow-up was 27 months and maximum was 105 months (average of 64 months). All children improved gait, patellar stability, Kujala (58.13%), and subjective IDKC (40.55%) scores and improved the congruence and the trochlea groove angles. CONCLUSION: The patellofemoral instability in children with DS is a challenge. We should use an arsenal of surgical techniques in this complex problem. We believe in early surgery to improve the formation of structures, especially in patients with gross instabilities and frequent falls. In all cases, we detected a weakness of medial components and lateral contracture, reconstructed the MPFL (we were the first researchers to describe this procedure for this group of patients), and performed a medial capsulectomy and lateral release. In some knees, intraoperatively, it was necessary to associate the reconstruction of the medial patellotibial ligament to improve instability. We consider fundamental analysis of the axis with panoramic radiographs and hemiepiphysiodes is in cases of asymmetric or severe valgus.

Biomechanical and histological comparison between the cryopreserved and the lyophilized Gracilis tendon allograft for MPFL reconstruction, a cadaveric experimental study.

BACKGROUND: Medial patellofemoral ligament (MPFL) is the main restrictor of lateral shifting of the patella, contributing by 60 % in the first 20° flexion of the knee. MPFL reconstruction has been performed in order to restore the stability of the patella with good results.Lyophilized Gracilis tendon allograft (LGA) compared to Cryopreserved Gracilis tendon allograft (CGA) has a lower cost, does not require to maintain cooling chain or preparation. The purpose of this study is to compare the histological and biomechanical characteristics of an experimental model of reconstruction of the MPFL in porcine patellas with LGA versus CGA. METHODS: Randomized controlled experimental study in porcine model conducted on 36 porcine patellas in which 18 were intervened with LGA and 18 were intervened with CGA. The confluent tunnel technique was used for MPFL reconstruction. Maximum tensile force, allograft elongation and stiffness of the construct were measured. The cellularity and collagen tissue distribution were evaluated in the allografts. The histological and biomechanical characteristics of the LGA were compared to those of the CGA. RESULTS: The median of the maximum tensile force for the LGA group was 299.63 N and 280.86 N for the CGA group (p = 0.45). The median of the stiffness was 57.86 N/mm for the LGA and 54.23 N/mm for the CGA (p = 0.2). The median of the elongation for the LGA was 5.95 mm and 6.12 mm for the CGA (p = 0,29). The bone bridge failed in 88.88 % of the constructs with LGA and 94.44 % in those with CGA (p = 0.5). CONCLUSIONS: No differences were observed between the LGA group and the CGA group in maximum tensile force, elongation, stiffness, site of rupture and histological characteristics. The use of a lyophilized Gracilis tendon allograft for MPFL reconstruction confers the same histological and biomechanical characteristics as a cryopreserved Gracilis tendon allograft.

Tratamiento de la inestabilidad femoropatelar objetiva / Treatment of objective patellofemoral instability

Introducción: El objetivo de este estudio es presentar los diferentes procedimientos quirúrgicos en el tratamiento de las inestabilidades femoropatelares objetivas, como la osteotomía de la tuberosidad tibial anterior y la trocleoplastia femoral. Materiales y Métodos: Se analizó el Índice de Caton-Deschamps para evaluar la altura rotuliana, la distancia desde la tuberosidad tibial anterior hasta la tróclea femoral en la tomografía computarizada, en el plano axial, y los morfotipos troclear y rotuliano. Se incluyeron 11 pacientes (11 rodillas) tratados por inestabilidad femoropatelar objetiva y documentada. Resultados: Los resultados fueron satisfactorios tanto con la transferencia de la tuberosidad tibial anterior como con la trocleoplastia. En ambos procedimientos, se realizó una reconstrucción del ligamento femoropatelar medial. La recurrencia de la inestabilidad es muy rara después de estos procedimientos y es más probable que sea secundaria a anomalías asociadas no diagnosticadas. Conclusión: Se requiere una planificación preoperatoria precisa para determinar la altura rotuliana, la ubicación de la tuberosidad tibial anterior, y los morfotipos troclear y rotuliano para lograr resultados satisfactorios. De todas formas y, como cualquier procedimiento quirúrgico, tanto las osteotomías de la tuberosidad tibial anterior, como la trocleoplastia pueden causar complicaciones.

Introduction: The aim of this study is to show the different surgical procedures for treating the objective patellar instability, including the different tibial tubercle osteotomies and the sulcus deepening trochleoplasty. Methods: This study analyzed the Caton-Deschamps index used for assessment of patellar height, the distance from the tibial tubercle to the troclear groove on CT scan in the axial view, and the different trochlear and patellar morphotypes. We included 11 knees (11 patients) treated due to an objective and documented patellofemoral instability. Results: We obtained good results with both the transfer of the tibial tuberosity and the trochleoplasty. A reconstruction of the medial patellofemoral ligament was performed in both procedures.Recurrence of instability is very rare after these procedures and this is more likely to result from missed associated abnormalities. Conclusion: Accurate preoperative planning of the patellar height and determining the location of the tibial tubercle and the trochlear and patellar morphotypes for satisfactory results are required. How ever, as with any surgical procedure, both tibial tubercle osteotomy and the sulcus deepening trochleoplasty are susceptible of complications.

Use of computed tomography to determine the risk of patellar dislocation in 921 patients with patellar instability.

The purpose of this research was to identify reliable tomographic measurements that can detect patellofemoral abnormality and allow quantification of the risk of patellar dislocation in patients with potential patellar instability. A cross-sectional study in 921 patients with anterior pain or knee instability of at least 6 months' duration was conducted from July 2001 to December 2009. All subjects were clinically evaluated and underwent radiography and computed tomography of their knees. According to their degree of dislocating patellar dysplasia, the subjects were classified into groups for statistical comparison. There was a statistically significant difference in all measurements when the groups were compared, except for external tibial torsion angle. The most sensitive and specific measurements for determining patellar instability were the trochlear groove angle, tibial tubercle-trochlear groove distance, average patellar tilt, and average patellar height. Patients with potential patellar instability, increased tibial tubercle-trochlear groove distance, and patellar height, tilt, and deviation measurements had a greater risk for patellar dislocation. The clinical relevance of this study is to determine measurements that are able to tell us about patellar dislocation risk.

Plicatura medial asistida por artroscopia a propósito de un caso / Arthroscopically-a medial plication: A case report

La plicatura medial asistida por artroscopia constituye una variedad quirúrgica empleada en pacientes que presentan mala alineación patelofemoral. El paciente de 44 años de edad, blanca, femenina con antecedentes de salud anterior, la cual desde hace aproximadamente un año refiere dolor a nivel de la cara anterior de la rodilla izquierda, para lo cual ha llevado tratamiento en múltiples ocasiones con analgésicos, antiinflamatorios no esteroideos y varias sesiones de terapia de rehabilitación con respuesta muy limitada a sus síntomas. Se realizó liberación del retináculo lateral acompañada de plicatura medial, esta técnica se describe por pasos. La plicatura medial asistida por artroscopia, es un procedimiento simple, que no necesita de una curva larga de aprendizaje y presenta un mínimo de complicaciones(AU)

Arthroscopically-assisted medial placation is a surgical variety used in patients with poor patellofemoral alignment. 44-year-old, white female patient, with previous health history of concerns, refers pain at the anterior aspect of her left knee for about a year. She has been treated with analgesics, NSAIDs multiple times and several rehabilitation therapy sessions with very limited response to her symptoms. Release of the lateral retinaculum accompanied by medial plication was performed on this patiente. This technique is described by steps. Assisted arthroscopic medial plication is a simple procedure which does not require long learning curve and it has a minimum of complications.

La plicature médiale assistée par arthroscopie constitue une technique chirurgicale employée chez les patients atteints dun mauvais alignement fémoro-pathélaire. Le cas dun patient (femme âgée de 44 ans, blanche) avec une historie de santé antérieure, référant depuis un an à peu près une douleur au niveau de la face antérieure du genou gauche, plusieurs traitements (analgésiques, antiinflammatoires non stéroïdiens), et pas mal de sessions de rééducation sans réponse satisfaisante, est présenté. On a effectué la libération du rétinaculum latéral, conjointement avec une plicature médiale. La plicature médiale assistée par arthroscopie est une procédure simple nayant pas besoin dune longue courbe dapprentissage et présentant très peu de complications(AU)

Plicatura medial asistida por artroscopia a propósito de un caso / Arthroscopically-a medial plication: a case report / Plicature médiale assistée par arthroscopie, à propos d'un cas

La plicatura medial asistida por artroscopia constituye una variedad quirúrgica empleada en pacientes que presentan mala alineación patelofemoral. El paciente de 44 años de edad, blanca, femenina con antecedentes de salud anterior, la cual desde hace aproximadamente un año refiere dolor a nivel de la cara anterior de la rodilla izquierda, para lo cual ha llevado tratamiento en múltiples ocasiones con analgésicos, antiinflamatorios no esteroideos y varias sesiones de terapia de rehabilitación con respuesta muy limitada a sus síntomas. Se realizó liberación del retináculo lateral acompañada de plicatura medial, esta técnica se describe por pasos. La plicatura medial asistida por artroscopia, es un procedimiento simple, que no necesita de una curva larga de aprendizaje y presenta un mínimo de complicaciones.

Arthroscopically-assisted medial placation is a surgical variety used in patients with poor patellofemoral alignment. 44-year-old, white female patient, with previous health history of concerns, refers pain at the anterior aspect of her left knee for about a year. She has been treated with analgesics, NSAIDs multiple times and several rehabilitation therapy sessions with very limited response to her symptoms. Release of the lateral retinaculum accompanied by medial plication was performed on this patiente. This technique is described by steps. Assisted arthroscopic medial plication is a simple procedure which does not require long learning curve and it has a minimum of complications.

La plicature médiale assistée par arthroscopie constitue une technique chirurgicale employée chez les patients atteints d’un mauvais alignement fémoro-pathélaire. Le cas d’un patient (femme âgée de 44 ans, blanche) avec une historie de santé antérieure, référant depuis un an à peu près une douleur au niveau de la face antérieure du genou gauche, plusieurs traitements (analgésiques, antiinflammatoires non stéroïdiens), et pas mal de sessions de rééducation sans réponse satisfaisante, est présenté. On a effectué la libération du rétinaculum latéral, conjointement avec une plicature médiale. La plicature médiale assistée par arthroscopie est une procédure simple n’ayant pas besoin d’une longue courbe d’apprentissage et présentant très peu de complications.

Inetabilidad patelofemoral / Patellofemoral instability

La inestabilidad rotuliana es una disfunción multifactorial. La estabilidad de la articulación patelofemoral depende de factores estáticos y dinámicos. Dentro de los estáticos está la anatomía ósea (rótula y tróclea), tejidos blandos (fundamentalmente LPFM) y el eje del miembro; y dentro de los dinámicos al cuádriceps. El diagnóstico es fundamental para indicar el tratamiento adecuado. Lo realizamos con la clínica, Rx y TAC. El tratamiento conservador puede ser indicado, aunque la incidencia de reluxación es alta. Se basa en rehabilitación. Con respecto al tratamiento quirúrgico en agudo en el primer episodio solo lo indicamos cuando hay una fractura osteocondral, avulsión ósea del LPFM, luxaciones incoercibles, rotura bien evidenciable del LPFM en fémur o alta demanda deportiva con factores de riesgo. En las inestabilidades crónicas las dos técnicas que se indican más frecuentemente son: la reconstrucción del LPFM cuando no hay alteraciones óseas de importancia, y la transposición de TAT cuando no hay un gran deseje o trastorno rotacional en cadera o tibia. El completo estudio de cada paciente en particular y el entendimiento de cómo y cuánto afecta cada uno de los factores causales de inestabilidad en forma individual, nos permite decidir un tratamiento. Este tratamiento estará dirigido a corregir funcional o quirúrgicamente las anomalías causales de la disfunción. Nivel de evidencia: V (AU)

Patellar instability is a multifactorial dysfunction. The stability of the patellofemoral joint depends on static and dynamic factors. Within the static ones are: the bony anatomy (patella and trochlea), the soft tissue one (mainly MPFL) and the axis of the member, and within the dynamic factors: the quadriceps. Diagnosis is essential to indicate the appropriate treatment which is done with the clinic, x-rays and CTs. The conservative treatment can be indicated but the incidence of redislocation is high. It is based on rehabilitation. With regard to the acute surgical treatment in the first episode, we indicate it when there is: an osteochondral fracture, an MPFL bony avulsion, uncontrollable dislocations, a well evidenciable MPFL femur tear, or in high Sports demand with risk factors. In chronic instability the two techniques that are frequently indicated are: MPFL reconstruction when there are no significant bone changes and/or TAT transposition when there is no important malalignment in femur or tibia. The thorough study of each patient and the understanding of how and to what extent each one of the causal factors of instability affects the patient in an individual way, allows us to decide on a treatment. This treatment will be aimed at correcting the causal anomalies of the dysfunction, functionally or surgically. Level of evidence: V (AU)

Inetabilidad patelofemoral / Patellofemoral instability

La inestabilidad rotuliana es una disfunción multifactorial. La estabilidad de la articulación patelofemoral depende de factores estáticos y dinámicos. Dentro de los estáticos está la anatomía ósea (rótula y tróclea), tejidos blandos (fundamentalmente LPFM) y el eje del miembro; y dentro de los dinámicos al cuádriceps. El diagnóstico es fundamental para indicar el tratamiento adecuado. Lo realizamos con la clínica, Rx y TAC. El tratamiento conservador puede ser indicado, aunque la incidencia de reluxación es alta. Se basa en rehabilitación. Con respecto al tratamiento quirúrgico en agudo en el primer episodio solo lo indicamos cuando hay una fractura osteocondral, avulsión ósea del LPFM, luxaciones incoercibles, rotura bien evidenciable del LPFM en fémur o alta demanda deportiva con factores de riesgo. En las inestabilidades crónicas las dos técnicas que se indican más frecuentemente son: la reconstrucción del LPFM cuando no hay alteraciones óseas de importancia, y la transposición de TAT cuando no hay un gran deseje o trastorno rotacional en cadera o tibia. El completo estudio de cada paciente en particular y el entendimiento de cómo y cuánto afecta cada uno de los factores causales de inestabilidad en forma individual, nos permite decidir un tratamiento. Este tratamiento estará dirigido a corregir funcional o quirúrgicamente las anomalías causales de la disfunción. Nivel de evidencia: V

Patellar instability is a multifactorial dysfunction. The stability of the patellofemoral joint depends on static and dynamic factors. Within the static ones are: the bony anatomy (patella and trochlea), the soft tissue one (mainly MPFL) and the axis of the member, and within the dynamic factors: the quadriceps. Diagnosis is essential to indicate the appropriate treatment which is done with the clinic, x-rays and CTs. The conservative treatment can be indicated but the incidence of redislocation is high. It is based on rehabilitation. With regard to the acute surgical treatment in the first episode, we indicate it when there is: an osteochondral fracture, an MPFL bony avulsion, uncontrollable dislocations, a well evidenciable MPFL femur tear, or in high Sports demand with risk factors. In chronic instability the two techniques that are frequently indicated are: MPFL reconstruction when there are no significant bone changes and/or TAT transposition when there is no important malalignment in femur or tibia. The thorough study of each patient and the understanding of how and to what extent each one of the causal factors of instability affects the patient in an individual way, allows us to decide on a treatment. This treatment will be aimed at correcting the causal anomalies of the dysfunction, functionally or surgically. Level of evidence: V

Inestabilidad patelofemoral / Patellofemoral instability

La inestabilidad patelofemoral es una de las enfermedades más frecuentes que afecta esta articulación, especialmente en los pacientes jóvenes. Por esta razón se realizó una revisión del tema con el objetivo de brindar un enfoque general que parte de las características anatómicas de esta articulación. Se muestran los elementos más importantes de la biomecánica conformada por geometría articular, alineación y comportamiento de ligamentos y músculos. Se muestran los signos radiológicos clásicos mediante el uso de la radiografía convencional, divididos en 4 grupos o modalidades según la clasificación de Dejour, además de la importancia de la tomografía axial computarizada y la resonancia magnética nuclear. Para concluir se mencionan algunas modalidades de tratamiento, comenzando por el conservador, y se analizan algunas modalidades de tratamiento quirúrgico y sus indicaciones, entre las que se encuentran la liberación del retináculo lateral, imbricación medial, realineación distal, plastia de la tróclea y traslado de la tuberosidad tibial hacia una zona más medial y anterior

Patellofemoral instability is one of the more frequent diseases affecting this joint, specially in young patients. Thus, a review on this subject was carried out to offer a general approach from the anatomical features of this joint. The more significant elements of the biomechanics are showed including the articular geometry, alignment and behavior of ligaments and muscles. The classic radiological signs are showed using the conventional X-rays divided into four groups or modalities according to the Dejour's classification as well as the significance of computerized axial tomography and the nuclear magnetic resonance. To conclude, some treatment modalities are mentioned including the conservative one and those of surgical treatment are analyzed as well as its indications including the lateral retinaculum release, the medial imbrication, the distal re-alignment, trochlea plastic surgery and movement of tibial tuberosity towards a more medial and anterior zone

L'instabilitÚ fÚmoro-patellaire est l'une des affections affectant le plus souvent cette articulation, spÚcialement chez les jeunes patients. À ce sujet, une rÚvision a ÚtÚ rÚalisÚe afin de donner une approche gÚnÚrale Ó partir des caractÚristiques anatomiques de cette articulation. Les ÚlÚments les plus importants de la biomÚcanique comprenant la gÚomÚtrie articulaire, l'alignement et le comportement des ligaments et muscles, sont montrÚs. Les signes radiologiques classiques sont Úgalement montrÚs, avec l'usage de la radiographie conventionnelle, et divisÚs en 4 groupes ou modalitÚs d'aprÞs la classification de Dejour; l'importance de la tomographie axiale informatisÚe et de la rÚsonance magnÚtique nuclÚaire est aussi mise en relief. Pour conclure, quelques modalitÚs du traitement chirurgical et ses indications, telles que la libÚration du rÚticulum latÚral, imbrication mÚdial, rÚalignement distal, plastie de la trochlÚe, et dÚplacement de la tubÚrositÚ tibiale vers une aire plus mÚdiale et antÚrieure, sont analysÚes