Effect of surgical fit on integration of cancellous bone and implant cortical bone shear strength for a porous titanium.

Porous scaffold dowels of Ti(6)Al(4)V were prepared and implanted into cancellous and cortical bone sites in adult sheep. Cancellous implants were examined under gap, line-to-line, and press-fit conditions, whereas line-to-line implantation was used in cortical sites. Cortical shear strength increased significantly with time and reached 26.1 ± 8.6 MPa at 12 weeks, accompanied by a concomitant increase in bone integration and remodeling. In cancellous sites, bone integration was well established at 4 and 12 weeks under conditions of press-fit and line-to-line match between implant and surgical defect. New bone growth was also found in the gap conditions, although to a lesser extent. These findings suggest that the porous Ti(6)Al(4)V could prove an effective scaffold material for uncemented fixation in cortical and cancellous sites.

A comparative study of surgical invasion in arthroscopic and open rotator cuff repair.

SUMMARY: This study investigated the degrees of surgical invasion for arthroscopic rotator cuff repair and open rotator cuff repair by evaluating the serum levels of C-reactive protein, hemoglobin, and interleukin-6. The study participants were 17 patients (group A) who underwent arthroscopic rotator cuff repair and 15 patients (group O) who underwent open rotator cuff repair by the same surgeon. The difference in the size of the rotator cuff tear between the 2 groups was not significant (P > .05). No significant differences were recorded in the postoperative serum levels of C-reactive protein and hemoglobin between the 2 groups (P > .05). The mean postoperative serum level of interleukin-6 was significantly lower in group A than in group O (P < .01). Our findings indicate that arthroscopic rotator cuff repair is less invasive than open rotator cuff repair.

Periacetabular osteotomy for the treatment of dysplastic hip with Perthes-like deformities.

We retrospectively evaluated 17 hips in 16 patients who underwent a periacetabular osteotomy for the treatment of dysplastic hip with Perthes-like deformities. These residual deformities were graded using the Stulberg classification system. There were three class II hips, 11 class III hips and three class IV hips preoperatively. The average age of the patients at surgery was 36.9 years and the average follow-up was 6.6 years. The average Harris hip score significantly improved from the preoperative value of 68.2 points to 91.1 points postoperatively. The average postoperative range of motion in all directions did not change significantly from the preoperative value. The average postoperative Harris hip score of class IV hips was smaller than that of the class II or class III hips. The standard radiographic evaluations also showed significant improvements postoperatively. Periacetabular osteotomy without combined femoral osteotomies, as a treatment for patients with Perthes-like deformities, produced good clinical and radiographic results.

Postoperative acetabular retroversion causes posterior osteoarthritis of the hip.

We retrospectively reviewed 68 hips in 62 patients with acetabular dysplasia who underwent curved periacetabular osteotomy. Among the 68 hips, 33 had acetabular retroversion (retroversion group) and 35 had anteversion (control group) preoperatively. All hips were evaluated according to the Harris hip score. Radiographic evaluations of acetabular retroversion and posterior wall deficiency were based on the cross-over sign and posterior wall sign, respectively. The clinical scores of the two groups at the final follow-up were similar. In the retroversion group, 12 hips had anteverted acetabulum postoperatively. The posterior wall sign disappeared in these hips, but remained in 21 hips with retroverted acetabulum postoperatively. Among the 21 hips with retroverted acetabulum, posterior osteoarthritis of the hip developed postoperatively in five hips. When performing corrective osteotomy for a dysplastic hip with acetabular retroversion, it is important to correct the acetabular retroversion to prevent posterior osteoarthritis of the hip due to posterior wall deficiency.

Comparison of skin blood flow between mini- and standard-incision approaches during total hip arthroplasty.

Twenty patients who underwent total hip arthroplasty were randomly allocated to have surgery through a mini incision of < or = 8 cm (mini-incision surgery [MIS] group, n = 10) or a standard incision of 14 cm (standard group, n = 10). A laser Doppler flowmeter was used to measure the intraoperative blood flow of the skin. The measurements were performed at 2 regions, specifically, anterior and posterior regions across the middle points of skin incision. The measurements were taken before making the incision and after implantation. As a control, the skin blood flow over the anterior superior iliac spine was measured. After implantation, mean skin blood flows at both regions in the MIS group were significantly decreased by 32% and 33%. However, the corresponding flows in standard group and control regions were constant during operation.

Effects of the lateral approach on blood flow of the gluteus medius and abductor function in total hip arthroplasty.

Total hip arthroplasty was performed in 19 patients using the lateral approach. Laser Doppler flowmetry was used to measure the blood flow in the anterior and posterior parts of the gluteus medius. The anterior part was split and detached. The posterior part was left intact. The blood flow in the gluteus medius of the anterior part was decreased by 15.4%, while that of the posterior part remained constant during surgery. Postoperatively, the Trendelenburg sign remained positive in 3 of 16 patients. No correlations were observed between a positive Trendelenburg sign and reduction in blood flow of the gluteus medius.

Pressure between the humeral head and the subscapularis tendon after the modified Boytchev procedure.

The pressure between the humeral head and the subscapularis tendon was determined in 32 patients who had recurrent anterior shoulder dislocations. These patients' pressures were measured during a modified Boytchev procedure both before and after transposition of the conjoined tendon, and they were remeasured at the time of screw removal, performed at a mean of 13 months after the initial surgery. The mean clinical follow-up period was 31 months. A micro-tip catheter transducer was inserted into the glenohumeral joint between the humeral head and the subscapularis tendon. Pressures were measured at particular degrees of motion for two positions: passive external rotation of the arm at the side at 0 degrees, 15 degrees, 30 degrees, 45 degrees, and 60 degrees and passive external rotation at the 90 degrees abducted position at 0 degrees, 30 degrees, 60 degrees, and 90 degrees. The pressures were statistically significantly higher after the conjoined tendon transfer at all measured degrees of motion in the two positions. The pressures at the time of screw removal were not statistically significantly different from those seen after the tendon transfer during external rotation at 90 degrees of abduction. The modified Boytchev procedure increases the pressure between the humeral head and the subscapularis tendon. We suspect that this increased pressure increases proprioceptive stimuli in the subscapularis tendon and thus accelerates the protective reflex needed to prevent shoulder dislocation.