Reproducibility of joint space width and the intermargin distance measurements in patients with medial osteoarthritis of the knee in various degrees of flexion.

OBJECTIVE: This study tested the variability and reproducibility of measurements of the joint space width (JSW) and intermargin distance (IMD) of the medial tibial plateau in specific positions of knee flexion in osteoarthritic knees in order to evaluate the most useful knee angle for radiographic measurements. DESIGN: Radiographs from 56 knees with osteoarthritis from 46 patients were taken with the knees in conventional full extension and 15 degrees , 30 degrees , and 45 degrees of flexion with weight bearing. Three orthopedic surgeons independently measured the JSW and IMD at the narrowest point and the midpoint of medial tibial plateau using a computer-assisted method. RESULTS: The JSW and IMD were smallest at 15 degrees flexion, both measured at the narrowest point and the midpoint of the medial compartment. Reproducibility of the IMD at the midpoint was better than at the narrowest point for all four flexion angles. CONCLUSION: Measurements of the medial JSW and IMD are smallest at 15 degrees of knee flexion indicating that radiographs should be obtained at this angle in order to best demonstrate the extent of osteoarthritis.

Safe zone for the superior gluteal nerve in the transgluteal approach to the dysplastic hip: intraoperative evaluation using a nerve stimulator.

BACKGROUND: The superior gluteal nerve can be damaged during the transgluteal approach to the hip in total hip arthroplasty. METHODS: We studied 30 patients with hip dysplasia who underwent total hip arthroplasty through the transgluteal approach. The course of the inferior branch of the superior gluteal nerve was identified using a nerve stimulator. The distance between the nerve and the tip of the greater trochanter was measured. RESULTS: The mean distance was 37 (25-45) mm at the anterior third, 40 (30-50) mm at the middle third, and 44 (35-55) mm at the posterior third of the gluteus medius. The distance was influenced by the severity of hip dysplasia and decreased as the degree of hip dysplasia became more severe. INTERPRETATION: A 3-cm safe zone is appropriate in most dysplastic hips. In severely dysplastic hips, however, the superior gluteal nerve occasionally coursed within 3 cm of the tip of the greater trochanter. In such hips, a nerve stimulator can be used to identify the nerve.

Femoral neck fractures in older patients: indication for osteosynthesis.

In almost all the patients over 65 years of age with intracapsular femoral neck fractures who we treated over a 2-year period, we used osteosynthesis with Ace 6.5-mm cannulated cancellous screws. We then followed them for at least 24 months. Each of the seven nondisplaced fractures healed. Of the 20 displaced fractures, 14 were rated as healed, 5 as failures, and 1 as a late segmental collapse. Among the 14 displaced fractures with an operative delay of 1 day, 12 healed, whereas only 2 of the 6 fractures with an operative delay of 2 days or more did so. Of the 12 typical fractures (with a medial spike in the head fragment), 10 healed, as did 4 of the 8 crescent or mixed-type fractures. The treatment of choice for nondisplaced fractures is osteosynthesis. Displaced fractures that occur on the day of operation or the day before should be treated with osteosynthesis if they are the typical type. The rest of the displaced fractures should be considered candidates for primary prosthetic replacement.

Posterior-anterior weight-bearing radiograph in 15 degree knee flexion in medial osteoarthritis.

OBJECTIVE: To evaluate the degree of knee flexion at which: (1) degenerative joint space narrowing is best seen, (2) the tibial plateau is best visualized and (3) the tibiofemoral angle is most correct, in order to assess the degree of flexion in the anteroposterior radiographic view that is most useful for assessing medial compartment osteoarthritis (OA) of the knee. DESIGN AND PATIENTS: We compared the conventional extended view of the knee and views at 15 degrees, 30 degrees, and 45 degrees of flexion with respect to joint space narrowing, alignment of the medial tibial plateau (MTP), and tibiofemoral angles in 113 knees of 95 patients with medial osteoarthritis of the knee (22 men, 73 women; mean age 67 years). RESULTS: At the midpoint and the narrowest point of the medial compartment, joint space narrowing values at 15 degrees, 30 degrees, and 45 degrees of flexion of the knee were smaller than that of the conventional extended view. Superimposition of the margins of the tibial plateau was satisfactory in 12% of patients in the conventional extended view, in 36% at 15 degrees of flexion, in 20% at 30 degrees of flexion, and in 19% at 45 degrees of flexion of the knee. When the knee was at 15 degrees of flexion there was a smaller difference in the tibiofemoral angle, in comparison with the knee extended, than was the case at 30 degrees and 45 degrees of flexion in patients with medial OA. CONCLUSION: A posteroanterior view with 15 degrees of flexion of the knee was able to detect joint space narrowing accurately, to achieve good alignment of the MTP in the medial compartment, and to reduce the difference in tibiofemoral angle compared with a view of the knee in conventional extension, and may be an alternative view in cases of medial OA of the knee.

Mechanoreceptors and length of the patellar ligament after Ho-YAG laser treatment: a long-term follow-up in rabbits.

We studied the shortening and the number of mechanoreceptors in the patellar ligament up to 18 months after Ho-YAG irradiation of the ligament's surface in 35 rabbits. The ligaments shortened an average 13% immediately after irradiation. After treatment, we divided the rabbits into a mobilized or immobilized group. At 2 weeks and 12 months after treatment both groups showed no shortening of the ligament, as compared to the intact ligament while that in the mobilized group had elongated at 12 months. Fewer Pacinian and Ruffini corpuscles were found in the irradiated ligaments than in the intact ones at 2 weeks after treatment, but we found no difference between irradiated and intact ligaments at 18 months after treatment.