The role of the meniscotibial ligament in posteromedial rotational knee stability.

PURPOSE: Tears of the posterior horn of the medial meniscus (PHMM) are very common in the ACL-deficient knee. Specific lesions of the PHMM have been described in the setting of ACL rupture: ramp lesions and injuries to the meniscotibial ligament. There are little data available regarding the role these lesions play in knee instability. The aim of this study is to analyse the biomechanical consequences of ramp and meniscotibial ligament lesions on knee stability. Our hypothesis was that these lesions would cause increased instability in the setting of ACL rupture. METHODS: A cadaveric study was undertaken: ten knees were included for analysis. The biomechanical repercussions of different meniscoligamentous injuries were studied in four stages: stage 1 involved testing the intact knee, stage 2 after transection of the ACL, stage 3 following creation of a ramp lesion, and stage 4 after detachment of the meniscotibial ligament. Four parameters were measured during the experiment: anterior tibial translation under a force of 134 N, internal and external tibial rotation under a torque of 5 Nm, and valgus angulation under a torque of 10 Nm. Measurements were taken in four knee flexion positions: 0° or full extension, 30°, 70°, and 90° of flexion. RESULTS: There was a statistically significant increase in anterior tibial translation for stage 2 (6.8 ± 1.3 mm, p ≤ 0.001), stage 3 (9.4 ± 1.3 mm, p ≤ 0.001), and stage 4 (9.3 ± 1.3 mm, p ≤ 0.001) compared to stage 1. There was no significant difference between stage 2 and stage 3 (2.6 mm, n.s.) or stage 4 (2.5 mm, n.s.). We did, however, demonstrate an increase in anterior tibial translation of 2.6 mm after the creation on a lesion of the PHMM compared to isolated division of the ACL, for all flexion angles combined. There was an increase in internal tibial rotation between stage 1 and stage 4 (3.2° ± 0.7°, p ≤ 0.001) and between stage 2 and stage 4 (2.0° ± 0.7°, p = 0.023). A significant difference was demonstrated for external rotation under 5 Nm torque between stages 4 and 1 (2.2° ± 0.5°, p ≤ 0.001) and between stages 4 and 2 (1.7° ± 0.5°, p = 0.007) for all knee flexion angles combined. No created lesion had a significant effect on medial laxity under a 10-Nm valgus torque at any degree of knee flexion. CONCLUSION: Lesions of the posterior horn of the medial meniscus are frequent in cases of anterior cruciate ligament rupture. These lesions appear to play a significant role in knee stability. Ramp lesions increase the forces in the ACL, and the PHMM is a secondary restraint to anterior tibial translation. Lesions of the meniscotibial ligament may increase rotatory instability of the knee.

Current surgical options for articular cartilage repair.

The articular cartilage lesions represent one of the major unsolved problems in the orthopaedic surgery. This is because articular cartilage has a limited capacity of self-repair following trauma. The aim of this study is to review the different surgical options for articular cartilage repair. They can be divided into three groups: techniques without transplant of cells or tissues; techniques based on the transplantation of tissues; the tissue engineering techniques.The first group includes the joint debridement and the techniques based on the bone marrow-stimulation principle.The second group includes the transplantation of periosteum and the transplantation of autologous or allogeneic osteochondral plugs. The tissue engineering techniques could be further divided as follows: methods based on the transplantation of cells either in solution, or in the form of microspheres, or carried on a biocompatible scaffold; the transplant of cartilage fragments; the cell-free techniques, based on the use of an acellular scaffold, able to entrap the reparative cells recruited from the host tissue and to guide their differentiation toward a chondral phenotype.In this work we present various options for the treatment of chondral or osteochondral lesions. Today, however, due to the lack of comparative studies, it is not always possible to define the best treatment choice for the different cartilage pathologies.

Reconstructing the chronically disrupted knee extensor mechanism after total knee arthroplasty: Hourglass variant of the original partial allograft technique.

Allograft reconstruction is a valuable treatment option for patients with chronic extensor mechanism disruption after total knee arthroplasty. Here, an hourglass variant of the original partial allograft technique is described. An hourglass-shaped patellar bone block is press-fit into the native patella. The graft is fixed to both the patella and the tibia then sutured with the knee fully extended. Outcomes of this technique were assessed in 5 patients after at least 24months' follow-up. The mean knee and function Knee Society Score values were 77.8 and 64.0, respectively. Extension lag was less than 10 in all 5 patients. This hourglass variant of the partial allograft technique is a useful treatment option that can be used even after patellar resurfacing.

A lateral approach to the distal humerus following identification of the cutaneous branches of the radial nerve.

We describe a lateral approach to the distal humerus based on initial location of the superficial branches of the radial nerve, the inferior lateral cutaneous nerve of the arm and the posterior cutaneous nerve of the forearm. In 18 upper limbs the superficial branches of the radial nerve were located in the subcutaneous tissue between the triceps and brachioradialis muscles and dissected proximally to their origin from the radial nerve, exposing the shaft of the humerus. The inferior lateral cutaneous nerve of the arm arose from the radial nerve at the lower part of the spiral groove, at a mean of 14.2 cm proximal to the lateral epicondyle. The posterior cutaneous nerve of the forearm arose from the inferior lateral cutaneous nerve at a mean of 6.9 cm (6.0 to 8.1) proximal to the lateral epicondyle and descended vertically along the dorsal aspect of the forearm. The size and constant site of emergence between the triceps and brachioradialis muscles constitute a readily identifiable landmark to explore the radial nerve and expose the humeral shaft.