Reliability of the acetabular reconstruction technique using autogenous bone graft from resected femoral head in hip dysplasia: Influence of the change of hip joint center on clinical outcome.

INTRODUCTION: The previous studies have not reached on consensus as to the outcome of acetabular reconstruction with autogenous bone graft for dysplastic hips, especially in severe cases such as Crowe type IV. The current study aimed to determine the survivorship of the arthroplasty and the grafts as well as the change of hip joint center averagely 9.8 years (range, 5-19) after cementless total hip arthroplasty. MATERIALS AND METHODS: We reviewed 52 cases including 19 cases of complete hip dislocation of which acetabular defects were augmented with autogenous bone grafts taken from the resected femoral heads. For radiographic evaluation, in addition to checking failures of THA, acetabular coverages of the grafts as well as lateral center-edge angles were measured and compared between two time points, immediately postoperative and the final evaluations. Those outcomes were also analyzed according to the degree of hip dysplasia, grouping the subjects by Crowe classification. Translations of the reconstructed hip joint center after THA were measured and checked if they affected clinical outcomes or caused any complications. To assess clinically, Harris hip score and visualized analogue pain scale were reviewed. RESULTS: Mean coverage ratio of the sockets with the grafts was 28.4% immediately after the surgery (range, 11.1%-65.0%) and 27.2% at the final follow-up (range, 11.1%-63.6%). When comparing high grade dysplasia (Crowe type III, IV) to low grade dysplasia (Crowe type I, II), there was no significant difference of the above outcomes (p = 0.476). As to the location of hip joint center, 14 outliers were located distally within the normal horizontal range especially in cases with Crowe type IV. Those outliers showed no difference on clinical outcome. The mean HHS was 52.2 (range, 19-87) and VAS was 7.2 (range, 5-9) preoperatively, each of which was improved to 92.9 (range, 63-100) and 1.4 (range, 0-4) postoperatively. No failures were experienced during the study period. CONCLUSIONS: Acetabular augmentation using autogenous bone graft from the resected femoral head is found to be a successful method for dysplastic hip, even in severe cases such as Crowe type IV, showing favorable results in more than 8 years. When inevitable, a degree of compromise on hip joint center can be needed in dealing with severe hip dysplasia.

Experimental measurement of tympanic membrane response for finite element model validation of a human middle ear.

The middle ear consists of a tympanic membrane, ligaments, tendons, and three ossicles. An important function of the tympanic membrane is to deliver exterior sound stimulus to the ossicles and inner ear. In this study, the responses of the tympanic membrane in a human ear were measured and compared with those of a finite element model of the middle ear. A laser Doppler vibrometer (LDV) was used to measure the dynamic responses of the tympanic membrane, which had the measurement point on the cone of light of the tympanic membrane. The measured subjects were five Korean male adults and a cadaver. The tympanic membranes were stimulated using pure-tone sine waves at 18 center frequencies of one-third octave band over a frequency range of 200 Hz ~10 kHz with 60 and 80 dB sound pressure levels. The measured responses were converted into the umbo displacement transfer function (UDTF) with a linearity assumption. The measured UDTFs were compared with the calculated UDTFs using a finite element model for the Korean human middle ear. The finite element model of the middle ear consists of three ossicles, a tympanic membrane, ligaments, and tendons. In the finite element model, the umbo displacements were calculated under a unit sound pressure on the tympanic membrane. The UDTF of the finite element model exhibited good agreement with that of the experimental one in low frequency range, whereas in higher frequency band, the two response functions deviated from each other, which demonstrates that the finite element model should be updated with more accurate material properties and/or a frequency dependent material model.

Penetration depth and size of the nonarthritic glenoid: implications for glenoid replacement.

Shoulder arthroplasty is technically demanding and relies heavily on precise surgical technique and preoperative planning. Proper glenoid component sizing plays a crucial role for successful shoulder arthroplasty. In this study, we measured the glenoid size together with penetration depth using three-dimensional computed tomography (3D-CT). From January 2010 to January 2011, 38 patients, including males and females, without evidence of a pathological glenoid, were enrolled for this study. CT images were taken and subsequently reconstructed in 3D images. The height of the glenoid was measured and the width was measured at five different levels (H1-H5). Axial images were taken at each level, with the anteroposterior (AP) glenoid diameter divided into eight areas (W1-W7). The penetration depth between the near and far cortices (thickness) at points W1-W7 was also measured. The overall mean height of the glenoid was 37.67 ± 4.09 mm. The width of the glenoid was the greatest at the distal 4/5th point and it was the least at the proximal 1/5th point. The penetration depth of the glenoid increased as the reference point progressed in the posterior direction, which was at the 5/7th point from the anterior margin. The measurement was greatest at the W4 point at the H1 level, but the W5 point was greatest at all other levels. On the basis of this study, the posterior and inferior parts of the glenoid are thinner than the anterior and superior parts. Thus, caution must be taken when inserting screws into the posteroinferior parts, where the glenoid is thinner than 15 mm, especially in females, to avoid penetration of the far cortex.

Resection arthroplasty for septic arthritis of the sternoclavicular joint.

BACKGROUND: Treatment for septic arthritis of the sternoclavicular (SC) joint with concomitant osteomyelitis of the clavicle often requires joint resection rather than simple incision and drainage. We evaluated the effectiveness of resection arthroplasty for patients with septic arthritis of the SC joint. METHODS: We retrospectively reviewed 10 patients who underwent resection arthroplasty for SC joint septic arthritis between 1996 and 2008. The mean patient age was 52.8 ± 10.5 years (range, 40-72 years), the mean symptom duration before surgery was 16.9 days (range, 2-60 days), and the mean follow-up period was 35.4 ± 42.2 months (range, 10-108 months). Diagnoses were based on physical examination, laboratory tests, and radiologic studies including magnetic resonance imaging. Each patient had concomitant osteomyelitis of the clavicle. In addition, 4 patients had mediastinitis and 1 had osteomyelitis of the adjacent ribs. All patients underwent SC joint resection and intramedullary ligament reconstruction, followed by intravenous antibiotics for 4 to 8 weeks. Intraoperative cultures were positive in 6 patients. RESULTS: All infections resolved, with only 1 patient having complications-systemic sepsis and pneumonia. The mean ranges of motion were 146° of forward flexion (range, 135°-155°) and 48° of external rotation (range, 40°-55°), with the internal rotation level ranging from T5 to L3. The mean superior migration of the clavicle was 1.5 mm (range, 0-4 mm), and the mean visual analog pain score was 1.4 ± 0.7 (range, 0-2). CONCLUSION: Resection arthroplasty in patients with septic SC joints results in relatively good shoulder function.