Disassembly of the inner head of a bipolar hip prosthesis.

We report an extremely rare case of inner head displacement from the stem of a bipolar hip prosthesis (BHP). An 88-year-old woman underwent BHP implantation for right femoral neck fracture. However, severe right hip joint pain occurred 12 days after surgery. A plain radiogram film revealed displacement of the inner head from the neck of the stem, accompanied by sinking of the stem. At reoperation, the inner head was disassembled from the stem, and Vancouver type A1 fracture was confirmed. Disassembly may have been caused by the pumping phenomenon or micromovement of the stem due to periprosthetic fracture. To our knowledge, this is the first report about disassembly of the BHP inner head, probably due to periprosthetic fracture.

Assessment of cervical myelopathy using transcranial magnetic stimulation and prediction of prognosis after laminoplasty.

STUDY DESIGN: This study investigated the clinical usefulness of motor-evoked potentials (MEPs) produced by transcranial magnetic stimulation of the brain for cervical myelopathy patients. OBJECTIVE: The purpose of this study was to determine the usefulness of MEPs for the assessment of the severity of myelopathy and prediction of the outcome of laminoplasty. SUMMARY OF BACKGROUND DATA: Magnetic stimulation has been widely used for examination of the descending excitatory motor pathways in the central nervous system, but little attention has been paid to cervical myelopathy. METHODS: We measured the MEPs of 56 patients who underwent surgery for cervical myelopathy. The MEPs from the abductor pollicis brevis, abductor digiti minimi, tibialis anterior, and abductor hallucis muscle were evoked by transcranial magnetic brain stimulation. The latency from the anterior horn cell of the spinal cord to the hand or foot muscles was also measured, with the F-value [(F + M - 1)/2] calculated. This was followed by estimation of the central motor conduction time (CMCT). Severity of clinical disability was scored on the basis of symptoms according to a modified ADL scale for cervical myelopathy of the Japanese Orthopedic Association (JOA) score. RESULTS: The average CMCT of the symptomatic side significantly correlated with the preoperative JOA score. The average CMCT of the symptomatic side significantly correlated with the 1-year postoperative JOA score. The average CMCT for patients with poor outcome was significantly longer than that for patients with good outcome. CMCT of 15 milliseconds or more in the upper extremities or that of 22 milliseconds or more in the lower extremities indicated poor prognosis. CONCLUSION: In patients with cervical myelopathy, the CMCT significantly correlated with the results of clinical assessment. These findings regarding the duration of CMCT may be useful parameters in spinal pathology for prediction of the outcome of surgical treatment.

Repair of articular cartilage and clinical outcome after osteotomy with microfracture or abrasion arthroplasty for medial gonarthrosis.

This study compared the healing of articular cartilage and the clinical outcome after osteotomy with or without marrow stimulation microfracture or abrasion arthroplasty for osteoarthritis of the knee. Patients with osteoarthritis of the medial compartment of the knee were divided into a group undergoing high tibial osteotomy alone (HTO group: 37 knees), a group undergoing osteotomy plus microfracture (MF group: 26 knees), and a group undergoing osteotomy plus abrasion arthroplasty (AA group: 51 knees). The extent of cartilage repair was compared at 1 year after surgery by arthroscopy with reference to Outerbridge's classification, while the clinical outcome was compared at 1, 3, and 5 years postoperatively. Second-look arthroscopy revealed better repair of the femoral condylar cartilage in the AA group than the HTO group (p<0.0005) or MF group (p<0.01), with no difference between the HTO and MF groups. Repair of the tibial condylar cartilage was also better in the AA group than the HTO group (p<0.005), but there was no difference between the AA and MF groups or the MF and HTO groups. There were no differences of the clinical outcome between the three groups. In conclusion, repair of articular cartilage at 1 year postoperatively was accelerated by abrasion arthroplasty, but not by microfracture. However, there was no difference of the clinical outcome within 5 years after surgery, so the clinical utility of marrow stimulation techniques was not apparent in this study.

Arthroscopic lateral meniscectomy in knees with lateral compartment osteoarthritis: a case series study.

PURPOSE: The purpose of this study was to investigate the intermediate-term postoperative results of arthroscopic surgery for lateral compartment osteoarthritis (OA) of the knee in a case series study. METHODS: In a series of 30 knees in 29 patients who underwent arthroscopic surgery for lateral compartment OA, we were able to observe 25 joints in 24 patients prospectively for the entire postoperative period. The follow-up period ranged from 1 to 13 years, with a mean of 5.5 +/- 3.7 years. The procedure in all cases comprised lateral partial meniscectomy with either abrasion arthroplasty, or debridement of the articular cartilage surface or microfracture. Of 25 cases, 13 underwent abrasion arthroplasty, 10 underwent debridement of the articular cartilage surface, and 2 underwent microfracture. Results were assessed by use of the postoperative knee score, findings of arthritic changes on plain knee radiographs, and other measurements of postoperative progress. RESULTS: Further surgery was required in 2 cases (8%) because of poor postoperative progress. In the remaining 22 patients, knee scores improved from a mean of 52.4 points preoperatively to 84.6 points postoperatively and mean function scores improved from 45.4 points to 82.6 points, with these favorable results being maintained at the last follow-up. The femoral-tibial angle decreased slightly as each year passed postoperatively. Radiologic progression of OA was seen at 3 years postoperatively in 7 patients (28%), but no progression was seen in 12 (48%). A positive correlation was seen between the preoperative femoral-tibial angle and postoperative results (R = 0.81, P < .01). CONCLUSIONS: When lateral compartment OA and lateral meniscal tears are both present, the clinical outcome of lateral meniscal resection was favorable. In patients with lateral compartment OA, therefore, an arthroscopic procedure, including meniscectomy, should be considered early. LEVEL OF EVIDENCE: Level IV, therapeutic case series.