Internal Structural Connections in the Popliteus Tendon Complex with Posterior Cruciate Ligament and Clinical Implications / Conexiones Estructurales Internas en el Complejo Tendón Poplíteo con Ligamento Cruzado Posterior e Implicaciones Clínicas

SUMMARY: At present, the anatomical relationship the mid-portion of popliteus tendon complex (PTC) and the surrounding tissues is still unclear, especially its relationship to the posterior cruciate ligament (PCL). It affected the anatomical reconstruction of the posterolateral complex (PLC) injury. A total of 30 cases of the adult human knee joint fixed with formalin were used. Sagittal sections were made in 14 knee joints by the P45 plastination technique and dissection of 16 cases of knee joints. The P45 section revealed that the popliteus muscle fascia ran superiorly over the posterior edge of the tibial intercondylar eminence, and turned forward to be integrated into the PCL. Laterally, near the posterior edge of the lateral tibial plateau, the popliteus tendon penetrates through the articular capsule (AC), where two dense fibrous bundles were given off upwards by the popliteus tendon: one was the ventral fiber bundle, which ran superiorly over the posterior edge of the tibial plateau and then moved forwards to connect with the lateral meniscus; the dorsal fibers bundle ascended directly and participated in the AC. Meanwhile, the popliteus muscle dissection showed that at the posterior edge of the platform of the lateral condyle of the tibia, at the tendon-muscle transition, the PTC and AC were anchored to PCL.

En la actualidad, la relación anatómica entre la porción media del complejo tendinoso poplíteo (CTP) y los tejidos circundantes aún no está clara, especialmente su relación con el ligamento cruzado posterior (LCP). Esto afecta la reconstrucción anatómica de la lesión del complejo posterolateral (LCP). Se utilizaron un total de 30 casos de articulaciones de rodillas humanas de individuos adultos fijadas con formalina. Se realizaron cortes sagitales en 14 articulaciones de rodilla mediante la técnica de plastinación P45 y disección de 16 casos de articulaciones de rodilla. La sección P45 reveló que la fascia del músculo poplíteo discurría superiormente sobre el margen posterior de la eminencia intercondílea tibial y giraba hacia delante para integrarse en el LCP. Lateralmente, cerca del margen posterior de la platillo tibial lateral, el tendón poplíteo penetra a través de la cápsula articular (CA), donde el tendón poplíteo desprendió hacia arriba dos haces fibrosos densos: uno era el haz de fibras ventral, que corría superiormente sobre el margen posterior de la meseta tibial y luego se movió hacia adelante para conectar con el menisco lateral; el haz de fibras dorsales ascendía directamente y participaba en la CA. Por su parte, la disección del músculo poplíteo mostró que en el margen posterior del platillo del cóndilo lateral de la tibia, en la transición tendón-músculo, el CTP y el AC estaban anclados al LCP.

[Evaluation and diagnosis of knee joint diagonal lesion and surgical strategy and effectiveness].

Objective: To investigate the evaluation, diagnosis, and surgical treatment of knee joint diagonal lesion and to observe its effectiveness. Methods: A retrospective analysis was performed on 9 patients with knee joint diagonal lesion admitted between November 2011 and November 2019, including 7 males and 2 females, aged 18-61 years, with an average age of 38.3 years. According to the clinical staging criteria of multiple ligament injury of knee joint, 6 patients with acute stage injury (≤3 weeks), the time from injury to operation was 5-16 days, with an average of 9.3 days; 3 patients with old stage injury (>3 weeks), the time from injury to operation was 7, 12, 144 months, respectively. Posterolateral complex injuries were all type C according to Fanelli classification, and the posterior cruciate ligament injury was grade 3 according to American Medical Association (AMA) classification. According to the three columns classification of tibial plateau fracture, there were 2 cases of zero column fracture and 7 cases of medial column fracture. Patients with acute injury were treated with posterior cruciate ligament reconstruction, posterolateral complex repair and/or reinforcement reconstruction, and tibial plateau fracture was treated with conservative treatment or internal fixation. Patients with malunion of tibial plateau in old stage were treated with limited osteotomy, bone grafting, and internal fixation; the stability of the knee joint was further evaluated during operation, then the posterior cruciate ligament reconstruction and/or posterolateral complex repair and reconstruction were performed as needed. Lysholm score and the International Knee Documentation Committee (IKDC) score before and after operation were used to evaluate knee function and effectiveness. Results: All patients were followed up 24-119 months, with an average of 51.7 months. All the incisions healed by first intention, and no complication such as incision infection, deep venous thrombosis of lower extremities occurred, and there was no reoperation during follow-up. The full-length X-ray films of both lower extremities at 6 months and 1, 2 years after operation showed that the alignment of both lower extremities returned to normal, and the stress position X-ray films showed that the stability in all directions recovered well. The X-ray films of the knee joint at 6 months after operation showed that the fracture of the tibial plateau healed well. At 1 year after operation, MRI showed that the signal of the repaired and reconstructed ligament was good, and there was no reconstruction failure such as ligament absorption or rupture occurred. At 1 year after operation, the muscle strength of the affected limbs was all rated as grade Ⅴ, and the active and passive range of motion of the knee joint recovered to 0°-130°. At 2 years after operation, the Lysholm score and IKDC score significantly improved when compared with those before operation (P<0.05). Conclusion: Knee joint diagonal lesion is a special type of posterior cruciate ligament and posterolateral complex injury with anteromedial split and collapse fracture of tibial plateau, which requires correct evaluation and diagnosis of the injured structure, and detailed surgical and rehabilitation programs to achieve better effectiveness.

Sequential damage assessment of the posterolateral complex of the knee joint: a finite element study.

BACKGROUND: The posterolateral complex (PLC), which consists of the popliteus tendon (PT), lateral collateral ligament (LCL), and popliteofibular ligament (PFL), is an indispensable structure of the knee joint. The aim of this study was to explore the functionality of the PLC by determining the specific role of each component in maintaining posterolateral knee stability. METHODS: A finite element (FE) model was generated based on previous material property data and magnetic resonance imaging of a volunteer's knee joint. The injury order of the PLC was set as LCL, PFL, and PT. A combined compressive load of 1150 N and an anterior tibial load of 134 N was applied to the tibia to investigate tibial displacement (TD). Tibial external rotation (TER) and tibial varus angulation (TVA) were measured under bending motions of 5 and 10 Nm. The instantaneous axis of rotation (IAR) of the knee joint under different rotation motions was also recorded. RESULTS: The TD of the intact knee under a combined compressive load of 1150 N and an anterior tibial load of 134 N matched the values determined in previous studies. Our model showed consistent increases in TD, TVA, and TER after sequential damage of the PLC. In addition, sequential disruption caused the IAR to shift superiorly and laterally during varus rotation and medially and anteriorly during external rotation. In the dynamic damage of the PLC, LCL injury had the largest effect on TD, TVA, TER, and IAR. CONCLUSIONS: Sequential injury of the PLC caused considerable loss of stability of the knee joint according to an FE model. The most significant structure of the PLC was the LCL.

[Short-term effectiveness of one-stage anterior and posterior cruciate ligaments and posterolateral complex reconstruction combined with medial collateral ligament repair for KD- â £ knee dislocation].

OBJECTIVE: To investigate the short-term effectiveness of one-stage anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), and posterolateral complex (PLC) reconstruction combined with medial collateral ligament repair for KD-Ⅳ knee dislocation. METHODS: Between January 2018 and June 2020, 9 patients with KD-Ⅳ knee dislocation were treated. Of 9 cases, 7 were male and 2 were female with an average age of 32.3 years (range, 23-43 years). The knee dislocation was caused by falling from height in 6 cases and traffic accident in 3 cases. The injury located at left knee in 2 cases and right knee in 7 cases. The time from injury to operation was 14-24 days, with an average of 19 days. The preoperative International Knee Joint Documentation Committee (IKDC) score was 45.6±4.2, Lysholm score was 42.4±7.0, and the knee joint active flexion range of motion was (75.2±12.3)°. The posterior drawer test, pivot-shift test, Dial test, and 0° valgus stress test were all positive. Under arthroscopy, PCL was reconstructed with the autologous tendons, ACL with allogeneic Achilles tendon, PLC with the allogeneic anterior tibial tendon by Larson enhanced reconstruction method, and MCL was repaired with anchor or simple suture. RESULTS: The operation time was 2-3 hours (mean, 2.5 hours). All incisions healed by first intention after operation. All patients were followed up12-25 months (mean, 16.1 months). After operation, 2 cases developed knee flexion disorder and pain, and 1 case had knee joint stiffness. At last follow-up, the IKDC score was 76.9±7.4, the Lysholm score was 81.6±6.4, and the knee active flexion range of motion was (122.9±7.2)°, all of which significantly improved when compared with preoperative ones ( P<0.05). During follow-up, there was no failure of the grafts. At last follow-up, there were significant differences in the posterior drawer test, pivot-shift test, Dial test, and 0° valgus stress test between pre- and post-operation ( P<0.05). The imaging review showed that the positions of the bone tunnels were satisfactory, the reconstructed ACL, PCL, and PLC structures were continuous, and MCL insertions were restored. CONCLUSION: One-stage ACL, PCL, and PLC reconstruction combined with MCL repair to treat KD-Ⅳ knee dislocation can effectively restore knee joint stability, improve joint laxity, and improve joint movement.

[Anatomical posterolateral complex reconstruction in treating severe posterolateral knee instability using Y-shaped allogeneic Achilles tendon].

OBJECTIVE: To investigate the surgical technique and effectiveness of anatomical posterolateral complex (PLC) reconstruction in treating severe posterolateral knee instability using Y-shaped allogeneic Achilles tendon. METHODS: The clinical data of 12 patients with Fanelli type C chronic PLC injury with severe posterolateral knee instability who met the selection criteria between June 2013 and August 2017 were retrospectively analyzed. There were 9 males and 3 females, with a median age of 34.5 years (range, 18-57 years). The average time from injury to surgery was 10.5 months (range, 3-24 months). All of them were multi-ligament injuries and were treated with anatomical reconstruction of Y-shaped allogeneic Achilles tendon. The posterior and varus stress X-ray films were used to measure and calculate the difference of posterior displacement of tibia and difference of lateral joint opening distance between bilateral knees to evaluate the backward stability of LCL and knee joint; the knee flexion 30° tibial external rotation test was used to calculate the difference of tibial external rotation angle between bilateral knees to evaluate the stability of knee external rotation. The knee function was evaluated by the International Knee Documentation Committee (IKDC) 2000 subjective and objective scores. RESULTS: The operation successfully completed in 12 patients, and there was no vascular and nerve injury during operation. The operation time was 2.5-3.5 hours, with an average of 2.7 hours; the intraoperative blood loss was 20-100 mL, with an average of 55 mL. All patients were followed up 13-41 months, with an average of 28.1 months. At last follow-up, the difference of posterior displacement of tibia, the difference of lateral joint opening, the difference of tibial external rotation angle between bilateral knees, and the IKDC2000 subjective score, the objective scores of tibial external rotation and knee varus significantly improved when compared with those before operation ( P<0.05). The knee joint of 1 patient with anterior cruciate ligament, posterior cruciate ligament, and PLC reconstruction was stiff at 15 months after operation, and the range of motion of the knee joint was 10°-80°. After arthroscopic release, the range of motion of the knee joint was 5°-120°, the reconstructed ligament was stable. In the other patients, the knee flexion angle was normal in 2 cases; 9 cases had knee flexion limitation of 5°-10°, with an average of 6.4°; no knee extension was limited. CONCLUSION: Anatomical PLC reconstruction using Y-shaped allogeneic Achilles tendon can effectively treat Fanelli type C chronic PLC injury with severe posterolateral knee instability and improve the knee joint stability.

Técnica de larson original modificada para la reconstrucción del ligamento colateral lateral de la rodilla, reporte de un caso / Modified original larson technique for the knee´s lateral collateral ligament reconstruction, a case report

El ligamento colateral lateral (LCL), que forma parte de los estabilizadores de la rodilla, constituye una estructura importante dentro del complejo posterolateral de la misma (CPL), que restringe al varo, en los ángulos de flexión de esta, especialmente a los 30°, además de controlar la rotación externa. Son infrecuentes las lesiones que afectan a este complejo, etiológicamente entre el 50- 90% se asocian a otras lesiones ligamentosas con predominio del 60% de daño del ligamento cruzado posterior. La técnica de Larson se basa en la reconstrucción del LCL y del complejo poplíteo, utilizando una inserción proximal única en el epicóndilo femoral. Presentamos el caso de un paciente masculino de 28 años de edad, sin antecedentes clínicos, que acude debido a un varo forzado de la extremidad mientras realizaba actividad deportiva y tras recibir impacto directo en la región lateral interna de pantorrilla derecha, posterior a lo cual presenta dolor a los movimientos pasivos e imposibilidad a la deambulación. Además, presenta equimosis, edema, escoriaciones superficiales en cara lateral externa y dolor a la digitopresión en trayecto de ligamento colateral externo. A maniobras de exploración de rodilla: signo de bostezo en varo positivo, cepillado rotuliano positivo, hiperpresión de rotula positivo, limitación funcional a la flexión y extensión de la articulación. Esta técnica, Larson modificada, resulta como una de las más prometedoras por sus varias características, como la menos exigente y al mismo tiempo brindando resultados alentadores. Este procedimiento se fundamenta en la reconstrucción del LCL y del tendón poplíteo (TP) en conjunto, resumiéndose así la reconstrucción del Ligamento Poplíteo Peroneo (LPP) como estabilizador estático del TP, con su inserción a nivel de la cabeza del peroné en conjunto con la del LCL y la restitución de ambas inserciones en el epicóndilo femoral, tomando en cuenta la morfología del peroné y los ángulos de movimientos de la rodilla.

The lateral collateral ligament (LCL), which is part of the knee stabilizers, constitutes an important structure within the posterolateral complex of the same (CPL), which restricts the varus, in the flexion angles of this, especially at 30°, in addition to controlling external rotation. Lesions that affect this complex are infrequent, etiologically between 50-90% are associated with other ligamentous injuries with a predominance of 60% damage to the posterior cruciate ligament. The Larson technique is based on the reconstruction of the LCL and the popliteal complex, using a single proximal insertion in the femoral epicondyle. We present the case of a 28-year-old male patient, with no medical history, who attended due to a forced varus of the limb while performing sports activity and after receiving a direct impact on the internal lateral region of the right calf, after which he presented pain to passive movements and inability to ambulation. In addition, he presents ecchymosis, edema, superficial abrasions on the external lateral aspect and pain on acupressure in the course of the external collateral ligament. A knee examination maneuvers: positive varus yawn sign, positive patellar brushing, positive patella hyperpressure, functional limitation to flexion and extension of the joint. This modified Larson technique turns out to be one of the most promising due to its various characteristics, as the least demanding and at the same time providing encouraging results. This procedure is based on the reconstruction of the LCL and the popliteal tendon (PT) as a whole, thus summarizing the reconstruction of the Peroneal Popliteal Ligament (LPP) as a static stabilizer of the PT, with its insertion at the level of the head of the fibula in conjunction with the of the LCL and the restitution of both attachments in the femoral epicondyle, taking into account the morphology of the fibula and the angles of movement of the knee.

Posterolateral reconstruction combined with one-stage tibial valgus osteotomy: Technical considerations and functional results.

BACKGROUND: To report the functional outcomes and complications from reconstructing the knee posterolateral complex (PLC), associated with one-stage opening-wedge tibial valgus osteotomy, and discuss the technical feasibility of this procedure. METHODS: Five patients with chronic PLC injuries and varus deviation of the mechanical axis, associated with central pivot injuries or not, underwent medial opening-wedge high tibial osteotomy combined with PLC reconstruction. The lateral collateral ligament, popliteal tendon, and popliteofibular ligament were reconstructed using a single femoral tunnel. Patients were assessed on physical examination, range-of-motion and functional scales, and radiographs. The International Knee Documentation Committee (IKDC) score, Lysholm score, and Knee Injury and Osteoarthritis Outcome score (KOOS) were determined. RESULTS: Five patients were evaluated: four presented with central pivot injury, and one had an isolated PLC injury. The mean time between injury and surgery was 40 ±â€¯6.5 months (± is indicating standard deviation value). Four patients had minimal residual instability on physical examination, with a lateral opening at varus stress of ±3+ at 30° flexion. The means of the IKDC score, Lysholm score, and KOOS were 67.8 ±â€¯9.2, 83.0 ±â€¯9.3, and 79.2 ±â€¯5.9, respectively. All patients showed satisfactory consolidation of osteotomy in 2.6 ±â€¯0.9 months. CONCLUSIONS: The results of this series indicate that one-stage PLC ligament reconstruction associated with medial opening-wedge valgus osteotomy is feasible and shows satisfactory functional results with a low rate of complications. A one-stage procedure might be indicated for young patients with high functionality and more pronounced posterolateral instabilities.

The role of isolated posterior cruciate ligament reconstruction in knees with combined posterior cruciate ligament and posterolateral complex injury.

PURPOSE: This is a meta-analysis comparing biomechanical outcomes to determine whether an isolated posterior cruciate ligament (PCL) reconstruction can restore normal knee kinematics in a combined PCL/posterolateral complex (PLC) injury and whether double-bundle (DB) PCL reconstruction is superior in controlling posterior and rotational laxity compared with single-bundle (SB) PCL reconstruction in a PCL/PLC-deficient knee. METHODS: A number of electronic databases were searched for relevant articles published through August 2016 that compared biomechanical outcomes of PCL reconstruction in patients who underwent reconstruction for combined PCL/PLC deficiencies. Data were searched, extracted, analysed, and assessed for quality according to Cochrane Collaboration guidelines, and biomechanical outcomes were evaluated using various outcome values. The results are presented as relative ratios for binary outcomes and standard mean differences for continuous outcomes with 95% confidence intervals. RESULTS: Five biomechanical studies were included in this meta-analysis. There were significant differences in laxities such as posterior tibial translation (PTT), external rotation, varus rotation, and PTT coupled with external rotation in the isolated PCL reconstruction group compared with the native PCL group. Furthermore, there were no significant differences in laxities such as PTT, external rotation, or varus rotation between the SB and DB PCL reconstruction groups. CONCLUSION: Isolated PCL reconstruction, whether SB or DB, could not restore normal knee kinematics in the PCL/PLC-deficient knee. In such cases, residual laxity after isolated PCL reconstruction can be controlled successfully with PLC reconstruction. Therefore, simultaneous PCL and PLC reconstruction is recommended for patients with combined PCL/PLC injury.

Biomechanical comparison of two surgical techniques for press-fit reconstruction of the posterolateral complex of the knee.

BACKGROUND: To date, various surgical techniques to treat posterolateral knee instability have been described. Recent studies recommended an anatomical and isometric reconstruction of the posterolateral corner addressing the key structures, such as lateral collateral ligament (LCL), popliteus tendon (POP) and popliteofibular ligament (PFL). Two clinical established autologous respective local reconstruction methods of the posterolateral complex were tested for knot-bone cylinder press-fit fixation to assess efficacy of each reconstruction technique in comparison to the intact knee. NULL HYPOTHESIS: The knot-bone cylinder press-fit fixation for both anatomic and isometric reconstruction techniques of the posterolateral complex shows equal biomechanical stability as the intact posterolateral knee structures. STUDY DESIGN: This was a controlled laboratory study. METHODS: Two surgical techniques (Larson: fibula-based semitendinosus autograft for LCL and PFL reconstruction/Kawano: biceps femoris and iliotibial tract autograft for LCL, PFL and POP reconstruction) with press-fit fixation were used for restoration of posterolateral knee stability. Seven cadaveric knees (66 ± 3.4 years) were tested under three conditions: intact knee, sectioned state and reconstructed knee for each surgical technique. Biomechanical stress tests were performed for every state at 30° and 90° knee flexion for anterior-posterior translation (60 N), internal-external and varus-valgus rotation (5 Nm) at 0°, 30° and 90° using a kinemator (Kuka robot). RESULTS: At 30° and 90° knee flexion, no significant differences between the four knee states were registered for anterior-posterior translation loading. Internal-external and varus-valgus rotational loading showed significantly higher instability for the sectioned state than for the intact or reconstructed posterolateral structures (p < 0.05). There were no significant differences between the intact and reconstructed knee states for internal-external rotation, varus-valgus rotation and anterior-posterior translation at any flexion angles (p > 0.05). Comparing both reconstruction techniques, significant higher varus-/valgus stability was registered for the fibula-based Larson technique at 90° knee flexion (p < 0.05). CONCLUSIONS: Both PLC reconstructions showed equal biomechanical stability as the intact posterolateral knee structures when using knot-bone cylinder press-fit fixation. We registered restoration of the rotational and varus-valgus stability with both surgical techniques. The anterior-posterior translational stability was not influenced significantly. The Larson technique showed significant higher varus/valgus stability in 90° flexion. The latter is easier to perform and takes half the preparation time, but needs grafting of the semitendinosus tendon. The Kawano reconstruction technique is an interesting alternative in cases of missing autografts.

Pure Varus Injury to the Knee Joint.

A 30-year-old male was involved in a car accident. Radiographs revealed a depressed marginal fracture of the medial tibial plateau and an avulsion fracture of the fibular head. Magnetic resonance imaging showed avulsion fracture of Gerdy's tubercle, injury to the posterior cruciate ligament (PCL), posterior horn of the medial meniscus, and the attachments of the lateral collateral ligament and the biceps femoris tendon. The depressed fracture of the medial tibial plateau was elevated and stabilized using a cannulated screw and washer. The injured lateral and posterolateral corner (PLC) structures were repaired and augmented by PLC reconstruction. However, the avulsion fracture of Gerdy's tubercle was not fixed because it was minimally displaced and the torn PCL was also not repaired or reconstructed. We present a unique case of pure varus injury to the knee joint. This case contributes to our understanding of the mechanism of knee injury and provides insight regarding appropriate treatment plans for this type of injury.