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Purpose: This study aimed to compare the biomechanical properties of the popliteus bypass against the Larson technique for the reconstruction of a combined posterolateral corner and posterior cruciate ligament injury., Methods: In 18 human cadaver knees, the kinematics for 134 N posterior loads, 10 Nm varus loads, and 5 Nm external rotational loads in 0°, 20°, 30°, 60,° and 90° of knee flexion were measured using a robotic and optical tracking system. The (1) posterior cruciate ligament, (2) meniscofibular/-tibial fibers, (3) popliteofibular ligament (PFL), (4) popliteotibial fascicle, (5) popliteus tendon, and (6) lateral collateral ligament were cut, and the measurements were repeated. The knees underwent posterior cruciate ligament reconstruction, and were randomized into two groups. Group PB (Popliteus Bypass; n = 9) underwent a lateral collateral ligament and popliteus bypass reconstruction and was compared to Group FS (Fibular Sling; n = 9) which underwent the Larson technique., Results: Varus angulation, posterior translation, and external rotation increased after dissection (p < 0.01). The varus angulation was effectively reduced in both groups and did not significantly differ from the intact knee. No significant differences were found between the groups. Posterior translation was reduced by both techniques (p < 0.01), but none of the groups had restored stability to the intact state (p < 0.02), with the exception of group PB at 0°. No significant differences were found between the two groups. The two techniques revealed major differences in their abilities to reduce external rotational instability. Group PB had less external rotational instability compared to Group FS (p < 0.03). Only Group PB had restored rotational instability compared to the state of the intact knee (p < 0.04) at all degrees of flexion., Conclusion: The popliteus bypass for posterolateral reconstruction has superior biomechanical properties related to external rotational stability compared to the Larson technique. Therefore, the popliteus bypass may have a positive influence on the clinical outcome. This needs to be proven through clinical trials.

The clinical examination of the knee joint represents a great challenge as well as a great opportunity. In particular, ligamentous injuries are understood better despite their complexity and thus treated in a more differentiated way. A purely radiologically based diagnosis is only possible to a limited extent, especially for chronic injuries. Therefore, complex ligament injuries can be diagnosed with the aid of a differentiated clinical examination. This article gives an overview of the most important examination techniques of the knee joint, with which the decisive analysis of acute or chronic injuries and overuse syndromes of the knee can be carried out. Particularly in the field of ligament instability, this article provides a practical guide for the differentiated examination of complex rotational instability of the knee joint. In addition, the most important patellar and meniscal examination techniques are described.

Background: Currently existing classifications of tibial plateau fractures do not help to guide surgical strategy. Recently, a segment-based mapping of the tibial plateau has been introduced in order to address fractures with a fracture-specific surgical approach. The goal of the present study was to analyze incidence and fracture specifics according to a new 10-segment classification of the tibial plateau., Methods: A total of 242 patients with 246 affected knees were included (124 females, 118 males, mean age 51.9±16.1years). Fractures were classified according to the OTA/AO classification. Fracture pattern was analyzed with respect to a 10-segment classification based on CT imaging of the proximal tibial plateau 3cm below the articular surface., Results: 161 Patients suffered an OTA/AO type 41-B and 85 patients an OTA/AO type 41-C tibial plateau fracture. Females had an almost seven times higher risk to suffer a fracture due to low-energy trauma (OR 6.91, 95% CI (3.52, 13.54), p<0.001) than males. In 34% of the patients with affection of the medial tibial plateau, a fracture comminution, primarily due to low-energy trauma (p<0.001), was observed. In type B fractures, the postero-latero-lateral (65.2%), the antero-latero-lateral (64.6%) and the antero-latero-central (60.9%) segment were most frequently affected. Every second type C fracture showed an unique fracture line and zone of comminution. The tibial spine was typically involved (89.4%). A typical fracture pattern of high-energy trauma demonstrated a zone of comminution of the lateral plateau and a split fracture in the medial plateau. The most frequently affected segments were the postero-latero-central (85.9%), postero-central (84.7%), and antero-latero-central (78.8%) segment., Conclusion: Posterior segments were the most frequently affected in OTA/AO type B and C fractures. Acknowledging the restricted visibility of posterior segments, whose reduction and fixation is crucial for long-term success, our findings implicate the use of posterior approaches more often in the treatment of tibial plateau fractures. Also, low-energy trauma was identified as an important cause for tibial plateau fractures., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Purpose: To evaluate knee laxity after anatomic ACL reconstruction with additional suture repair of a medial meniscus tear., Methods: Kinematics of the intact knee were determined in 12 human cadaver specimens in response to a 134-N anterior tibial load (aTT) and a combined rotatory load of 10 Nm valgus and 4 Nm internal tibial rotation (aTTPS) using a robotic/universal force moment sensor testing system. Subsequently, the ACL was resected following the creation of a standardized tear of the medial meniscus, a standard meniscus repair and an ACL reconstruction using an anatomic single-bundle (6) or an anatomic double-bundle technique (6). Knee kinematics were determined following every sub-step., Results: Significant increase of aTT in the ACL-deficient knee was found (p ≤ 0.001) with a further increase in the ACL-deficient knee with additional medial meniscal rupture (p ≤ 0.001). ACL reconstructions significantly decreased aTT compared with the ACL and meniscus-ruptured knee. No significant differences were seen between the intact knee and the ACL-reconstructed knee with additional meniscal repair (p < 0.05). In response to a simulated pivot shift, aTTPS in the intact knee significantly increased in the ACL-deficient knee and meniscus-ruptured knee (p = 0.005). No significant differences in knee kinematics were found between SB as well as DB ACL reconstruction with additional medial meniscal repair compared with the intact knee. Comparison of SB versus DB ACL reconstruction did not reveal any significant differences in a simulated Lachman test or simulated pivot shift test (n.s.)., Conclusions: aTT as well as aTTPS significantly increased with ACL deficiency compared with the intact knee; additional medial meniscal rupture further increased aTT. Anatomic ACL reconstruction with medial meniscal repair did not reveal significant differences in knee kinematics compared with the intact knee. Comparison of anatomic SB versus DB ACL reconstruction with additional repair of the medial meniscus did not show significant differences neither in a simulated Lachman nor in a simulated pivot shift test.

Objective: The aim of arthroscopically assisted treatment of tibial plateau fractures is to achieve minimally invasive reduction and internal fixation of the joint fracture of the tibial plateau. Using the arthroscopic procedure, both the approach morbidity and the control of the articular reduction can be optimized., Indications: Displaced tibia plateau fractures of AO type A1 and B1/2/3 or Tscherne P2., Contraindications: Strongly displaced tibial plateau fractures, which require an open surgical approach and stabilization with plate fixation (e.g., AO type C fractures or Moore type 5 fractures); 2nd and 3rd degree open fractures. Danger of compartment syndrome., Surgical Technique: Planning of the surgical approach and confirmation of the indication by CT imaging. Diagnostic arthroscopy of the knee joint with treatment of associated injuries and confirming the indications for arthroscopically assisted reduction. Under arthroscopic control, insertion of an ACL tibial aiming device. In the central portion of the dislocated fracture fragment, a 2.4 mm K-wire is placed with the help of the aiming device. Opening of the outer cortex using a cannulated drill (9-11 mm diameter), introduction of a cannulated plunger below the fracture resulting in reduction of the fracture and compression of the cancellous bone below the fracture. Simultaneously the reduction is controlled by arthroscopy. Finally, the fracture is fixed using minimally invasive screw fixation (3.5-7.3 mm cancellous screws with washers) or by plate osteosynthesis (e.g., support plate). The metaphyseal defect can optionally be filled with bone substitute material., Postoperative Management: Rehabilitation is dependent on the extent of the fracture. In arthroscopically treated fractures, partial weight bearing of 20 kg over a period of 6-12 weeks is usually necessary.