The range of motion (ROM) after total knee arthroplasty (TKA) is one of the most important factors for patient satisfaction, especially in Asian countries. To enhance the knee flexion angle, “high-flexion” designs have been introduced in total knee prostheses. One of such design was a new design of femoral prosthesis, which increased the posterior cut on the bone by 2 mm and thickened the posterior condyle, allowing the posterior condylar radius to continue further. There were several reports on postoperative ROM of such “high-flexion” posterior-stabilized (PS) total knee prosthesis. However, there was no report on the postoperative ROM of “high-flexion” cruciate ligament retaining (CR) total knee prosthesis. The purpose of this study was to compare the ROM associated with standard and high-flexion posterior CR total knee prostheses.

One hundred and fifty-one consecutive patients (176 knees) had CR total knee prosthesis. 89 knees had standard CR TKA (NexGen CR, Zimmer, Warsaw, IL), and 87 knees had high-flexion CR knee prostheses (NexGen CR-Flex, Zimmer, Warsaw, IL). Differences in the age, diagnosis, preoperative Knee Society Score (KSS), and preoperative ROM of the knee between two groups were not significant. At one year postoperatively, the patients were assessed clinically and radiographically.

The mean postoperative KSS knee score was 96.2 points for the standard CR prosthesis group and 96.7 points for the high-flexion CR prosthesis group (p=0.464). The mean postoperative KSS function score was 83.4 points for the standard CR prosthesis group and 84.8 points for the high-flexion CR prosthesis group (p=0.446). The mean postoperative ROM was 110.8 degrees in the standard CR prosthesis group, and 114.0 degrees in high-flexion prosthesis group (p=0.236). No knee had aseptic loosening, revision, or osteolysis.

Previous report showed that “high-flexion” PS design did not increase postoperative ROM compared to standard design. However, there was no report on the postoperative ROM of “high-flexion” CR total knee prosthesis. We found no significant differences between the standard CR group and “high-flexion” CR group with regard to ROM or clinical and radiographic parameters. However, in the cases which achieved high flexion, “high-flexion” design, which chamfered posterior femoral edge, can reduce the possibility of deformation from posterior contacts under lord. Therefore, the results of the current study suggested that “high-flexion” CR design is not the design that increase ROM significantly, but might be the safe design even when the knee achieved deep flexion.

The aim of the present investigation is to study the status of the blood-nerve barrier in the carpal tunnel syndrome and cubital tunnel syndrome using gadolinium enhanced MRI.

The subjects were 68 patients (92 hands) with idiopathic carpal tunnel syndrome and 21 patients (23 elbows) with cubital tunnel syndrome.

The MRI equipment used was a 0.3-T permanent magnet. Using the SE method, T1-weighted axial images were obtained. Then, we intravenously injected gadolinium for enhanced images. We studied the relationship between nerve enhancement and the symptoms of the patients.

Out of 92 hands with carpal tunnel syndrome, 74 hands (80%) showed enhancement of the median nerve. The patients had 58 hands classified as Grade I (sensory disturbance only) out of which 44 hands (76%) showed nerve enhancement , as did 25 out of 29 hands (86%) classified as Grade II (I + thenar muscle atrophy) and all 5 hands (100%) classified as Grade III (II + disturbance of opposition). Enhancement was more prominent in the patients with thenar muscle atrophy. All 23 elbows with cubital tunnel syndrome revealed enhancement of the ulnar nerve. Two elbows were categorized as grade I (sensory disturbance only), 12 as grade II (I + 1’st inter-osseus muscle atrophy), and 9 as grade III (II + claw finger deformity)

In general, capillaries exist inside the endoneurial spaces of peripheral nerves. Intraneural homeostasis is maintained by the perineurium as a diffusion barrier and by the blood-nerve barrier existing in the endothelium. MRI could demonstrate intraneural enhancement at the site of nerve entrapment where intraneural edema resulted from an increase in the vascular permeability of the endoneurium. We conclude that gadolinium-enhanced MR imaging can detect morphological and functional changes of peripheral nerve in patients with entrapment neuropathy.