Introduction: It is difficult to measure the knee kinematics after TKA, navigation system can measure the knee kinematics during TKA operation. The purpose of this study is to describe the knee kinematic analysis in TKA using navigation system.

Patients and methods: TKA kinematics was measured in 24 patients (7 men and 17 women) 27 knees (7 rheumatoid arthritis knees and 20 osteoarthritis knees) in this study. Mean age was 72.8 (55–81). The TKA implant was Vanguard PS (Biomet, Warsaw) and navigation system was Vector Vision Knee ver. 1.6 (BrainLab Inc). All patients were operated using navigation system. This system was CT-based navigation system. We cut the bone independently and released medial collateral ligament, joint capsule and other tight structures to equal the joint balance. Femoral component was implanted parallel to clinical epicondylar line. Kinematic Analysis: We measured the joint gap (mm), coronal alignment (degree), antero-posterior translation (mm) and femoral rotation angle (degree) using navigation workstation just after all prostheses implantation and closure of joint capsule. The patient’s leg was held by operator and moved passively. All joint kinematic data were recorded at every 10 degrees in full range of motion (0 to 130 degrees). The joint gap is the distance between proximal tibial cut surface and that of distal femur (extension range: 0–40) and posterior femur (flexion range: 50–130). Medial and lateral distances were measured.

Results: In extension range, medial joint gap was 21.7mm at 0 degrees and decreased to 15.2mm with knee flexion. Lateral joint gap was 22.1mm at 0 knee extension, slightly decreased up to 40 degrees. Coronal alignment was 0.47 varus at 0 deg. and increased to 6.64 varus at 40 flexion. In flexion range, medial and lateral joint gap were increased 20.7 to 25.3, 17.2 to 31.2mm. Coronal alignment was c hanged from 4.94 valgus (60 flexion) to 8.94 varus (130 full flexion). Regarding to AP translation, femoral component was once moved 7.4 mm forward in early knee flexion and 15.2mm backward with flexion. Femoral components were rotated internally to 50 degrees flexion and then rotated externally with flexion.

Conclusion: The balance of TKA was still varus alignment after soft tissue release. Femoral components were moved backward and external rotation. Our results demonstrated that femoral rollback movement and medial pivot knee motion were recognized. The limitation of this study was the situation of under anesthesia and no muscle strain were loaded during the measurement of knee kinematics. However navigation system is available not only for the accurate implantation but also the measurement of intra operative knee kinematics.

Introduction: The efficacy and complications of the transarticular screw procedure have been reported by many authors. However, few have reported this procedure for child younger than 10 years old. We have treated two children for atlantoaxial subluxation with transarticular screws, using a soft collar without a halo-vest, and have achieved bone union in good reduced position.

Methods/results

Case 1: a 5-year-old boy with mental retardation and cerebellar infarction due to an insufficiency of the vertebral artery resulting in severe atlantoaxial instability. He presented with a high degree of congenital atlantoaxial subluxation complicated by Os odontoideum. He has been treated with transarticular screw and iliac bone graft by Brooks procedure.

Case 2: an 8-year-old boy with congenital spondyloepiphyseal dysplasia and a right valgus knee. He, too, presented with a high degree of congenital atlantoaxial subluxation complicated by Os odontoideum, and has been treated with transarticular screw and iliac bone graft by Brooks procedure.

In both cases, we used two half-thread cortical screws with a diameter of 2.7mm and a length of 30mm for the transarticular screw procedure.

Discussion/conclusion: Rigid external fixation was obtained by Halo-vest. This method, however, would be expected to cause mental stress for the child patient and the family. More rigid internal fixation would be required to resolve this problem. More rigid internal fixation can be obtained with the transarticular screw, and postoperative orthosis can be performed easily, without the need for a Halo-vest.

Nine children sustained a second fracture of the distal humerus after union of an ipsilateral supracondylar fracture which had healed with cubitus varus. There were eight boys and one girl with a mean age of five years (1 to 8) at the time of the second fracture which occurred at a mean of 1.5 years after the first. In all patients, the second fracture was an epiphyseal injury of the distal humerus, either associated with a fracture of the lateral metaphysis below the site of the previous supracondylar fracture, or a fracture-separation of the entire distal humeral epiphysis. This suggests that the physis and epiphysis tend to be more subject to injury than the metaphysis of the distal humerus in children who have had a previous supracondylar fracture with varus malunion.

We treated 12 shoulders in ten patients with irreparable rotator-cuff tears by transfer of the latissimus dorsi. There were nine men and one woman. Their average age was 64.0 years and the average follow-up was 35.6 months (26 to 42).

The results were excellent in four shoulders, good in four, fair in one, and poor in three. Active forward flexion improved from a preoperative average of 99° to a postoperative average of 135°. Osteoarthritic changes appeared in five shoulders and proximal migration of the humeral head progressed in six. EMG revealed that nine of the 12 transferred muscles showed activity which was synergistic with the supraspinatus on external rotation with abduction.

We conclude that latissimus dorsi transfer can be effective in restoring shoulder function after massive irreparable tears of the rotator cuff.