Application of 3D Printing Technology in the Treatment of Hoffa's Fracture Nonunion / Aplicação da tecnologia de impressão 3D no tratamento da pseudartrose da fratura de Hoffa

Abstract Objective To evaluate a proposed three-dimensional (3D) printing process of a biomodel developed with the aid of fused deposition modeling (FDM) technology based on computed tomography (CT) scans of an individual with nonunion of a coronal femoral condyle fracture (Hoffa's fracture). Materials and Methods Thus, we used CT scans, which enable the evaluation of the 3D volumetric reconstruction of the anatomical model, as well as of the architecture and bone geometry of sites with complex anatomy, such as the joints. In addition, it enables the development of the virtual surgical planning (VSP) in a computer-aided design (CAD) software. This technology makes it possible to print full-scale anatomical models that can be used in surgical simulations for training and in the choice of the best placement of the implant according to the VSP. In the radiographic evaluation of the osteosynthesis of the Hoffa's fracture nonunion, we assessed the position of the implant in the 3D-printed anatomical model and in the patient's knee. Results The 3D-printed anatomical model showed geometric and morphological characteristics similar to those of the actual bone. The position of the implants in relation to the nonunion line and anatomical landmarks showed great accuracy in the comparison of the patient's knee with the 3D-printed anatomical model. Conclusion The use of the virtual anatomical model and the 3D-printed anatomical model with the additive manufacturing (AM) technology proved to be effective and useful in planning and performing the surgical treatment of Hoffa's fracture nonunion. Thus, it showed great accuracy in the reproducibility of the virtual surgical planning and the 3D-printed anatomical model.

Resumo Objetivo Avaliar uma proposta de processo de impressão tridimensional (3D) de um biomodelo preparado com o auxílio da tecnologia de modelagem por deposição de material fundido (fused deposition modeling, FDM, em inglês) a partir de imagens de tomografia computadorizada (TC) de um indivíduo com pseudartrose de fratura coronal do côndilo femoral (fratura de Hoffa). Materiais e Métodos Para tanto, utilizamos imagens de TC, que permitem estudar a reconstrução volumétrica 3D do modelo anatômico, além da arquitetura e geometria óssea de sítios de anatomia complexa, como as articulações. Também permite o planejamento cirúrgico virtual (PCV) em um programa de desenho assistido por computador (computer-aided design, CAD, em inglês). Essa tecnologia possibilita a impressão de modelos anatômicos em escala real que podem ser utilizados em simulações cirúrgicas para o treinamento e a escolha do melhor posicionamento do implante de acordo com o PCV. Na avaliação radiográfica da osteossíntese da pseudartrose de Hoffa, verificou-se a posição do implante no modelo anatômico impresso em 3D e no joelho do paciente. Resultados O modelo anatômico impresso em 3D apresentou características geométricas e morfológicas semelhantes às do osso real. O posicionamento dos implantes em relação à linha de pseudartrose e pontos anatômicos foram bastante precisos na comparação do joelho do paciente com o modelo anatômico impresso em 3D. Conclusão A utilização do modelo anatômico virtual e do modelo anatômico impresso em 3D com a tecnologia de manufatura aditiva (MA) foi eficaz e auxiliou o planejamento e a realização do tratamento cirúrgico da pseudartrose da fratura de Hoffa. Desta forma, foi bastante preciso na reprodutibilidade do planejamento cirúrgico tanto virtual quanto no modelo anatômico impresso em 3D.

Discussion on internal fixation of Hoffa fractures / 中国骨伤

Hoffa fracture is an unstable intra-articular fracture with significant redisplacement tendency. It is easy to be missed diagnosis when accompanied by distal intercondylar or supracondylar fracture of femur. CT scan is the gold standard for the diagnosis of Hoffa fracture. The treatment principles are anatomic reduction of the articular surface, reliable internal fixation, and early functional activity. At present, the main treatment is arthroscopic screw fixation. During screw fixation, the tail cap of screw should be buried, resulting in non-healing iatrogenic injury of articular cartilage. In the early postoperative functional activity of knee joint, fracture block was repeatedly subjected to backward and upward shear force under the action of the tibial plateau, which is the main reason for the failure of internal fixation. Plate assisted screw fixation could increase local mechanical stability, but it still cannot avoid the defects of iatrogenic cartilage injury. At the same time, plate molding is required during the operation due to the absence of special anatomical plates, resulting in increased surgical trauma and time-consuming surgery. The ideal fixation method for Hoffa fracture should include:(1) Avoid iatrogenic injury of articular surface cartilage. (2) With the rear anti-shear barrier plate function.(3) The internal fixator is closer to the load interface, so as to obtain greater load and better fixed strength.

Fractura de Hoffa medial: reporte de un caso / Medial Hoffa fracture: a case report

Resumen: Introducción: Las fracturas del cóndilo femoral en el plano coronal o fracturas de Hoffa se encuentran entre las fracturas más raras del miembro pélvico, pero son aún más raras las del cóndilo medial. El éxito en el manejo de estos pacientes radica en el diagnóstico oportuno y la consecuente reducción anatómica de la superficie articular del fémur. Caso clínico: El objetivo de este reporte es presentar a un paciente con el diagnóstico de fractura de Hoffa medial derecha, registrado como caso único en los archivos de nuestro hospital. El paciente acudió referido en Noviembre de 2011, con evolución de 10 días tras sufrir caída de caballo, presentando mecanismo de varo forzado y contusión directa de la rodilla derecha. Mostró radiografías anteroposterior y lateral de rodilla derecha, donde se observó de forma sutil solución de la continuidad en el plano coronal de la base del cóndilo medial, corroborado por resonancia magnética y asociado a lesiones parciales no quirúrgicas de ambos meniscos y del ligamento cruzado anterior. Se intervino quirúrgicamente el día 27 de Noviembre de 2011 mediante reducción abierta con abordaje medial y fijación interna con dos tornillos canulados de 7.0 mm. Se egresó al paciente indicando la movilización temprana y continua de la rodilla, difiriendo el apoyo y rehabilitación hasta la sexta semana. Actualmente el paciente se encuentra con posibilidad de deambulación, asintomático y con arcos de movilidad completos. El respeto del aparato extensor mediante un abordaje medial y la superficie articular con tornillos canulados se refleja en la adecuada evolución de nuestro paciente, pudiendo regresar a sus actividades diarias, incluso el montar.

Abstract: Introduction: Knee femoral condyle coronal fractures or Hoffa fractures are among the rarest fractures of the pelvic limb, being even more rare those of the medial condyle. The success in the management of these patients lies in the timely diagnosis and the consequent anatomical reduction of the femoral articular surface. Clinical case: The objective of this article is to present a patient with right medial Hoffa fracture, registered as a single case in the archives of our hospital. The patient was referred to us on November 2011, with a 10-day course after suffering a fall from horse ridding, presenting a forced varus mechanism and direct contusion of the right knee. He shows an anteroposterior and lateral knee X-rays showing a subtle solution of continuity in the coronal plane of the base of the medial condyle, corroborated with magnetic resonance imaging and was also associated with a non-surgical partial injury of both menisci and the anterior cruciate ligament. Surgical intervention was performed on 27th/11/2011, through open reduction with a medial approach and internal fixation with 7.0 mm (x2) cannulated screws. The patient was discharged with early and continuous mobilization of the knee, deferring support and rehabilitation until the 6th week. He is currently a wandering patient, asymptomatic, with complete range of motion. Because respecting the extensor apparatus through a medial approach and the articular surface with cannulated screws, it was observed in consequence an adequate evolution of our patient, being able to return to his daily activities, even remount.

A Novel Technique for Fixation of Non-union Unicondylar Hoffa’s Fracture: A Case Report

@#Hoffa fractures are rare and difficult fractures to manage. Hoffa fracture involves a coronal plane fracture of posterior femoral condyle. Non-union in Hoffa fracture is further difficult to manage. The surgical management for such nonunion includes open reduction with recon/LCP plate or screw fixation with bone grafting. The problem with plates is the difficulty in contouring the plates according to the shape of posterior femoral condyles. We describe a new technique with 2 L shaped neutralisation plates placed in a circular fashion. This technique provides a more rigid construct and gives better holding strength of screws in Hoffa fragment. This enhances union and mobilisation can be started early.

Fractura de Hoffa en el cóndilo femoral. Reporte de caso / Femur Hoffa fracture. A case report

Las fracturas de tercio distal de fémur unicondilares en el plano coronal son conocidas como fracturas de Hoffa, son poco frecuentes y muy raras. Se han reportado pocos casos este tipo de fracturas, por definición son fracturas inestables y por lo tanto requieren de resolución quirúrgica. El mecanismo de trauma en este tipo de fracturas es directo con la rodilla en flexión. Muchas veces pueden pasar desapercibidas en las proyección radiográficas anteroposterior (AP), y por eso es importante evaluar la proyección lateral. Cuando se sospechan o se evidencian es necesario tomar una tomografía axial computarizada (TAC) con el fin de definir claramente su su resolución quirúrgica, puesto que el abordaje y el método de fijación es controversial. Aunque hoy en día ha aumentado la disponibilidad y las características delos diferentes tipos de implantes, no hay un consenso en la literatura debido principalmente a la falta de experticia en estos poco frecuentes casos.

Unicondylar coronal plane fractures of the distal third of the femur are known as Hoffa fractures, are uncommon and rather rare. Only few cases of this type of fracture have been reported worldwide. By definition they are unstable fractures and therefore require surgical resolution. The mechanism of trauma in this type of fracture is an anterior to posterior direct trauma with a flexed knee. They can often go unnoticed on the anterior-posterior (AP) radiographic projection, so it is important to carefully evaluate the lateral projection. When they are suspected or perhaps evident, it is necessary to perform a computerized axial tomography (CT) in order to clearly define both, the characteristics of the fracture itself as the surgical resolution options, since the approach and the fixation method are controversial. Although nowadays the availability and characteristics of the different types of implants have increased, there is no consensus about the way to manage these fractures in medical literature, mainly due to the lack of expertise in these rare cases.

Hoffa Fracture of Medial Femoral Condyle in a 9-Year-Old Child: A Case Report

Hoffa fractures are intra-articular fractures of the distal femoral condyles in coronal plane. These fractures may be of either condylebut lateral condyle is most commonly affected and medial condyle is extremely rare. Non-operative treatment of unicondylarfemur fractures, including Hoffa fractures, yields poor result. We present a case of 9-year-old child with Hoffa fracture of medialfemoral condyle with understanding of the mechanism of injury and its further management. He had history of fall from height ofabout 5 feet on his right knee which was in flexed position at around 90°. X-ray of knee showed fracture of medial femoral condylein coronal plane. Three-dimensional (3D) reconstruction of computed tomography (CT) scan confirmed the coronal fracture ofmedial femoral condyle and was classified as Type 33 B3 according to orthopedic trauma association classification and Type 1as per Letenneur classification. Open reduction and internal fixation were performed with partially threaded cancellous screws.The fixation of coronal fracture of medial femoral condyle done through cancellous screws in anterior to posterior direction wasadequate in giving stable fixation and aided in union without disturbing the physis of the child. At 1 year, the child could do fullextension and 130° flexion. There was no posterior or varus, valgus instability of the knee. We believe that a medial condyleHoffa fracture is extremely rare in children, and the diagnosis can be missed. ORIF using partially threaded cancellous screwsin the epiphysis provides stable fixation and can lead to a good functional outcome in the long term. The mechanism of injuryin this fracture pattern was found to be direct impact on the knee in flexed position of 90°.

Principios quirúrgicos y biomecánicos de los métodos de fijación actual en el tratamiento de fracturas de Hoffa / Surgical and biomechanical principles of current fixation methods, in treatment of Hoffa fractures

Las fracturas de los cóndilos femorales en el plano coronal (Hoffa), son lesiones que afectan directamente la biomecánica de la rodilla. Están expuestas a un factor intrínseco de inestabilidad causado por el compromiso de los ligamentos y tendones insertados al fragmento condilar fracturado y a un factor extrínseco de inestabilidad dependiente del estrés mecánico en varo/valgo durante la fase de apoyo de la marcha y movimientos de flexo-extensión. El tratamiento quirúrgico con tornillos canulados sólo permite la compresión interfragmentaria y cierto grado de estabilidad rotacional, sin embargo, ese tipo de fijación podría no ser suficiente para soportar o neutralizar las cargas. Distintos autores han publicado otros métodos de osteosíntesis con el uso de placas en el plano lateral o posterior más la colocación de tornillos en sentido postero-anterior, pero siguen siendo opciones controversiales debido al tipo de morbilidad inherente a cada constructo. El objetivo de este artículo es realizar una revisión de la literatura para analizar la validez de los principios quirúrgicos y biomecánicos en el tratamiento de fracturas tipo hoffa.

Coronal plane fractures of the femoral condyles are commonly known as Hoffa fractures. These are intraarticular fractures that directly affect the biomechanics of the knee and have intrinsic and extrinsic instability patterns. The tendons and ligaments that remain attached to the condylar fragment produce the intrinsic instability. The extrinsic instability is due to the varus/valgus stress applied during the stance phase in the gait cycle as well as the flexion-extension movements. Surgical treatment with cannulated screws only achieves interfragmentary compression and certain amount of rotational stability that is not enough to support or neutralize the loads. Some authors have published different methods of osteosynthesis with lateral or posterior plates in conjunction with screws implanted in the posterior-anterior direction, still these techniques remain controversial due to the morbidity inherent to each construct. The purpose of this article is to review the current concepts of Hoffa fractures including biomechanics and surgical principles with the intention of analyzing their treatment efficacy.

An attempt to treat Hoffa fractures under arthroscopy: A case report / 中华创伤杂志(英文版)

We treated a 15-year-old female patient with fracture of the post-lateral femoral condyle and the bone shifted in front of the knee. Considering that the traditional surgical approach has the shortcomings of significant trauma and poor prognosis, we designed an arthroscopic procedure, which achieved satisfactory short-term efficacy, effectively reduced and fixed the fractures, avoided damage to vascular nerves, and maximally reduced the trauma caused by surgery itself.

Research progress of Hoffa fracture / 中华外科杂志

Hoffa fracture is a rare type of fracture confined to the coronal plane of the femoral condyle. High-energy is a common reason of Hoffa fracture, and low-energy trauma and iatrogenic injury can also cause Hoffa fracture in some cases. The commonly used classifications include Letenneur classification, CT classification, AO classification and modified AO classification. X-ray is the first choice to diagnose Hoffa fractures, fracture lines can be found. If the X-ray is negative, CT scan and MRI should be performed. Nondisplaced fractures can be managed conservatively with cast immobilization, however, there is high risk of redisplacement. Open reduction and internal fixation is preferred. For the young patient with good compliance, a simple medial or lateral condylar fractures can be treated via medial or lateral parapatellar approach. When the fracture is exposed, the headless compression screws can be inserted vertical to the fracture line from backward to forward. For a bicondylar fracture, median parapatellar incision can be selected. While for a complex fracture with osteoporosis or high body mass index, cannulated screws with anti-sliding plate fixation technique should be used.

Functional Outcome of Isolated Hoffa Fractures Treated with Cannulated Cancellous Screw

Introduction: Isolated Hoffa fracture is an infrequent injury and little research has been done on this subject. The purpose of this study was to evaluate the functional outcome and complications of surgically managed Hoffa fractures with cannulated cancellous screw. Materials and Methods: Between 2011 and 2014, eight isolated Hoffa fractures in seven adult patients with mean age 39.8±11.9 years (range 25-60 years) were managed with cannulated cancellous screw of 6.5mm diameter applied in anterior to posterior direction using swashbuckler and medial parapatellar approach for lateral and medial Hoffa fractures respectively. All patients were evaluated using knee evaluation score after two years or longer. Mean follow up was 28±3.8 months (range 24-36 months). Results: All fractures in the eight patients healed clinicoradiologically by the 16th week with excellent result in 87.5% cases and good in 12.5% cases. By the end of union, the range of motion (ROM) of the knee was 0° to 110° except in two patients. One patient had ROM 10°-100° and other had 15°-90°. Mean knee evaluation score was 87.5±10.4. There was no incidence of non-union, infection or avascular changes in the patients or loss of reduction till final follow up. Conclusion: Open reduction and fixation with two 6.5 mm cannulated cancellous screws with early mobilization yielded good functional outcome in isolated Hoffa fractures.

Analysis on effect of posterior anti-rotation plate combined with cancellous screw for treating unicondylar Hoffa fracture / 重庆医学

Objective To investigate the clinical efficacy of posterior anti‐rotation plate plus cancellous screws for treating unicondylar Hoffa fracture and to systematically analyze its injury mechanism ,clinical diagnosis ,treatment method and clinical fol‐low up results .Methods The imageological and clinical data in 9 cases of unicondylar Hoffa fractures treated by anti‐rotation plate plus cancellous screws from March 2009 to April 2014 were retrospectively analyzed .Results All fractures were healed within 4 months .The average follow up time of the patients was 34 months(24~50 months) .Seven cases obtained the anatomic reduction and 2 cases got the satisfactory reduction .The reduction loss and fixation failure were not found in all the cases .One cases of wound infection occurred early after operation and healed within 1 week after anti-infection .One case of knee joint ankylosis complicating pain occurred during the follow up period .According to the KSSs scoring standard ,the knee joint prognosis function scores were ex‐cellent in 4 cases ,good in 4 cases and poor in 1 case .Conclusion Using anti‐rotation plate combined with cancellous screws for con‐ducting the Hoffa fracture fixation can confront the strong shear force beard by femoral condyle with the advantages of rigid fixa‐tion ,reliability fixation and early weight bearing functional exercise .

Tratamiento quirúrgico de la fractura posterior del condilo femoral / Femoral condylar posterior fracture: Surgical treatment / Traitement chirurgical de la fracture postérieure du condyle fémoral

Las fracturas distales del fémur representan solamente el 6 por ciento de todas las fracturas femorales. Presentamos el caso de un paciente masculino de 42 años que sufrió accidente del transito, que le provocó fractura unicondilar del extremo distal del fémur en el plano coronal, conocida como fractura de Hoffa. Se muestra el tratamiento quirúrgico realizado mediante estudios radiológicos, donde se utilizó tornillo del sistema AO. Con este tipo de proceder se obtuvo reducción y estabilidad de la fractura. Se concluye que una planificación preoperatorio adecuada es necesaria para obtener resultados satisfactorios.

Femoral distal fractures accounts for only the 6 percent of all femoral ones. Authors present the case of a male patient aged 42 suffered a road accident provoking a unicondylar fracture of femur distal end in coronal plane , known as Hoffa fracture. Surgical treatment by radiological studies is showed, where we used a screw of AO system. Using this procedure we achieved the fracture reduction and stability. We conclude that an appropriate preoperative planning is necessary to get satisfactory results.

Les fractures distales du fémur ne représentent que 6 percent de toutes les fractures fémorales. Dans ce travail, le cas d'un patient âgé de 42 ans, ayant souffert un accident de la route qui lui a provoqué une fracture condylienne de l'extrémité distale du fémur sur le plan coronal, connue par fracture d'Hoffa, est présenté. Un traitement chirurgical basé sur des études radiologiques, et dans lequel une vis du système AO est utilisée, est exposé. On a constaté une réduction et une stabilité de la fracture grâce à cette procédure. On peut conclure qu'une planification préopératoire est nécessaire pour obtenir des résultats satisfaisants dans ces cas.

Treatment effect of the coronal fractures of the femoral condyle with open reduction and internal fixation / 中国矫形外科杂志

[Objective] To discuss the method and clinical effects of coronal fractures of the femoral condyle treated with open reduction plus cancellous lag screw internal fixation.[Method]From May 1998 to June 2006,17 cases of coronal fractures of femoral condyle were treated with open reduction 'and cancellous lag screw internal fixation by using anterolateral for typ Ⅰ or typ Ⅲ lateral femoral condylar fracture(LFCF)/anteromedial for type Ⅰ or type Ⅲ medial femoral condylar fracture(MFCF)or posterolateral for type ⅡLFCF/posteromedial approach for type Ⅱ MFCF.There were 15 males and 2 females with the average age 39.5 years,ranging from 19 to 48 years.According to Letenneur classification,there were type Ⅰfracture 7 cases,type Ⅱ 4 cases,and type Ⅲ 6 cases.Among them,14 cases were closed fracture,3 eases were open fracture.Auto ilium transplant or homologous allograft bone transplant(5 cases)were also used.All patients were treated with plaster external fixation after operation.The interval between injury and surgery averaged 3.6 days(2.5 hours to 8 days).[Result]All patients were followed up for 8～26 months with an average of 18.2 months.All fractures got bone union with average union time 3.6 months.Knee joint function was rated based on Letenneur evaluation system and showed excellen and good in 14 cases,fine in 3 cases and no poor.There were no deep infection,implant failure or bone necrosis.[Conclusion]Open reduction plus cancellous lag screw internal fixation is an ideally safe and effective operation to treat coronal fractures of the femoral condyle.Accurate choice of approach,satisfactory reduction and rigid internal fixation have important influence on clinical outcomes.

Treatment of Hoffa facture associated with extensor mechanism injury / 中国矫形外科杂志

[Objective]To investigate the injury characteristics and treatment of the Hoffa facture associated with extensor mechanism injury.[Method]Four patients with Hoffa facture associated with extensor mechanism injury treated in author's hospital in recent 6 years were enrolled in this study.All the patients were multiple-injured,and associated with the ipsilateral limb fracture and retinacular and capsule laceration.The site of the extensor mechanism injury included 1 distal patellar tendon disruption,2 proximal patellar tendon disruption,and 1 distal quadriceps tendon disruption.No cruciate ligament injury was found in 3 ipsilateral bicondylar fractures.One unicondylar fracture was associated with anterior and posterior cruciate ligament and medial collateral ligament injury simultaneously.Emergency operation was performed along with the debridement in the three open fractures.In another patient with closed fracture,operation was performed one week after injury.Fractures were reduced and fixed with lag screws.Extensor apparatus were repaired and strengthened with a tension band wire through both patella and tibia.Ipsilateral limb fractures were reduced and internal fixed with hardware simultaneously. The knees were immobilized in extension with cast after operation,and flexion exercise was commenced four to six weeks later.[Result]Four patients wounds reached the first rate healing.There was no infection and necrosis of skin.All patients were followed-up for six months to three years.All 7 condyles of the 4 patients reached bone union.Healing time was about six to twelve weeks.According to Letenneur’s functional assessment system,excellent and good results were in 1 cases,fine in 3 cases.[Conclusion]Hoffa facture associated with extensor mechanism injury are usually accompanied with injuries in other part of the body.In open fracture,emergency operation is mandatory,and fracture reduction and internal fixation and extensor apparatus repair should be performed along with debridement.Tension band wire may strengthen the stability of the extensor mechanism and facilitated early mobilization.

Usefulness of MRI in Distal Femoral Intra-articular Fracture

PURPOSE: Preoperative recognition of an associated injuries including ligament disruptions of the knee and Hoffa fracture in the cases of the intra-articular distal femoral fractures affects surgical planning. The purpose of this study is to identify the usefulness of MRI in distal femoral intraarticular fracture. MATERIALS AND METHODS: Over a 7 years period from January 1995 to December 2001, all patients with an intra-articular fracture of the distal femur were collected from a prospectively designed orthopaedic database and reviewed. Seventy five patients with intra-articular distal femoral fractures were collected. There were 49 male and 26 female patients ranging from 15 to 91 in age. Because these injuries usually result from high-energy trauma, we should also exclude associated injuries of pelvis, hip, patella, tibial plateau fractures, popliteal vessel injuries, and ligament disruptions of the knee. So we checked knee MRI of patients with distal femoral fractures to rule out associated knee injuries. RESULTS: There were 12 Hoffa's fractures, 6 anterior cruciate ligament injuries, 6 posterior cruciate ligament injuries, 10 medial collateral ligament injuries and 3 lateral collateral ligament injuries. Five patients of 12 Hoffa's fractures associated with intra-articular distal femoral fractures that were not diagnosed in patients with conventional radiographs were confirmed after MRI evaluation. CONCLUSION: Knee MRI for intra-articular distal femoral fracture is necessary to rule out associated ligament injuries and Hoffa fractures in case of high-energy trauma patients.