Tomihisa Koshino

Medial Opening-Wedge High Tibial Osteotomy with Use of Porous Hydroxyapatite to Treat Medial Compartment Osteoarthritis of the Knee

Background: The aims of this study were to investigate the results of opening-wedge high tibial valgus osteotomy in patients with medial compartment osteoarthritis of the knee and to examine the usefulness of hydroxyapatite wedges as the supporting material.Methods: Medial opening-wedge osteotomy was performed in twenty-one osteoarthritic knees in eighteen patients who had a mean age of 66.6 years. The mean duration of follow-up was 78.6 months. A medial transverse osteotomy was performed proximal to the tibial tuberosity, with the most lateral 10% of the tibia left intact. The medial side of the osteotomy site was opened to the desired angle of correction. Two hydroxyapatite wedges of the same size (5.0, 7.5, or 10.0 mm) were inserted into the opened osteotomy site along with bone grafts, and the fragments were fixed with two plates. The angle of correction could be adjusted by altering the direction of wedge insertion. The goal was to achieve a final standing alignment of 10° of anatomical valgus angulation.Results: All patients had pain relief and improvement in walking ability after the osteotomy. The mean knee and function scores of the American Knee Society were 60.2 ± 5.3 and 48.1 ± 10.4 points, respectively, before the osteotomy and 94.3 ± 7.3 and 93.1 ± 9.8 points, respectively, at the time of the final follow-up. Limb alignment, expressed as the standing femorotibial angle, was corrected from 180° ± 2.9° preoperatively to 169.7° ± 3.7° (10.3° of anatomical valgus angulation) at the time of the latest follow-up. There were no cases of recurrence of varus deformity or collapse of the hydroxyapatite wedges.Conclusions: After a mean duration of follow-up of 6.6 years, we found that the medial opening-wedge osteotomy of the proximal part of the tibia provided satisfactory clinical results for patients with osteoarthritis of the knee. Use of the porous hydroxyapatite wedges resulted in no collapse or subsidence at the osteotomy site.Level of Evidence: Therapeutic study, Level IV (case series [no, or historical, control group]). See p. 2 for complete description of levels of evidence.

Effect of acetabular cup position and orientation in cemented total hip arthroplasty.

Long-term clinical results of total hip arthroplasty for patients with developmental acetabular dysplasia of the hip have been reported, but placement of the femoral head center or cup orientation remains controversial, especially with a severe anterolateral shallow acetabulum or dislocated femoral head. Results of 41 Müller and 34 Harris Design 2 cemented total hip arthroplasties were evaluated for developmental dysplasia of the hip. The femoral head center and acetabular cup inclination angle were measured from the interteardrop line. Linear wear and wear direction were measured using the Livermore technique. The best position of the femoral head center was less than 35 mm vertically from the interteardrop line and 25 mm laterally from the teardrop. Femoral head center analysis showed that hips with the cup in a lateral and superior cup position all were revised, but a superior and medial position combined with a cup inclination angle less than 40° did not require revision. Hips with a cup inclination angle more than 45° had superior and lateral penetration patterns of the polyethylene. However, hips with an inclination angle less than 35° and medial placement had medial head penetration patterns. With these all-polyethylene monolithic cemented cups, regardless of the femoral head diameter or cup thickness, better long-term results occurred with a cup inclination angle of 40° or less and medial position of the cup.

Comparison of cyclooxygenase-1 and -2 inhibitory activities of various nonsteroidal anti-inflammatory drugs using human platelets and synovial cells.

Recent studies have shown that cyclooxygenase exists in two isozyme forms. Since differences in the pharmacological profiles of nonsteroidal anti-inflammatory drugs (NSAIDs) might be accounted for by varying degrees of selectivity for these isozymes, cyclooxygenase-1 and -2, the relative potency of various NSAIDs in inhibiting their activities was examined in intact human cells. We used human platelets cyclooxygenase-1 and interleukin-1beta-stimulated human synovial cell cyclooxygenase-2 for measuring cyclooxygenase selectivity. The presence of the enzymes was confirmed by immunoblotting and immunoprecipitation analysis, and by the reverse transcriptase-polymerase chain reaction. Mean IC50 values (microM) for human platelet cyclooxygenase-1 and interleukin-1beta-stimulated human synovial cell cyclooxygenase-2 and cyclooxygenase-1/-2 IC50 ratio of various NSAIDs were as follows: aspirin, 3.2, 26, 0.12; diclofenac, 0.037, 0.00097, 38; etodolac, 122, 0.68, 179; ibuprofen, 3.0, 3.5, 0.86; indomethacin, 0.013, 0.044, 0.30; loxoprofen (active metabolite), 0.38, 0.12, 3.2; NS-398, 12, 0.0095, 1263; oxaprozin, 2.2, 36, 0.061; zaltoprofen, 1.3, 0.34, 3.8; respectively. Our bioassay system employing intact human cells to assess the cyclooxygenase selectivity of NSAIDs may provide clinically useful information.

Distribution of neuropeptides in synovium of the knee with osteoarthritis.

Synovial tissue was obtained from medial, lateral, and suprapatellar sites of 21 knees (15 patients) with medial compartmental osteoarthritis at surgery. All patients reported pain around the medial joint of their knees while walking and climbing stairs. For investigation of the synovial innervation, six samples were stained with modified gold chloride and the others with an immunohistochemical method using antisera against neuropeptides. The extent of synovitis in each part was scored using a new 10-point scale. The results showed that the synovium had an extensive neural network in the somatic and autonomic nervous systems. Neuropeptides were most abundant, with an especially large number of substance P and calcitonin gene related peptide immunoreactive free nerve endings. Some of the substance P positive nerve endings were surrounded by monocytes. Substance P and calcitonin gene related peptide were found more frequently in the medial than in the lateral or suprapatellar areas. Substance P positive free nerve endings showed more dendritic morphologic features in the medial region than did those in the lateral and suprapatellar regions, and small nerves were accompanied by newly developed vessels in synovial villi. In the medial region, the synovitis was more remarkable than in the lateral region. These findings suggest that free nerve endings containing substance P may modulate inflammation and the pain pathway in osteoarthritis.

Osteogenic response of rabbit tibia to hydroxyapatite particle-Plaster of Paris mixture.

A mixture of hydroxyapatite (HA) particles and plaster of Paris (POP) with saline solution was injected into the bone marrow of 30 unilateral tibiae of 30 rabbits. As a control, POP with saline solution was similarly injected into the bone marrow of 30 unilateral tibiae of 30 additional rabbits. Five rabbits in each group were killed 2, 4, 8, 12, 24 and 40 weeks after injection. Histological examination was performed on three tibiae of five killed animals, and X-ray diffraction analysis of the bone marrow was performed on the remaining two tibiae. In two of three tibiae, bridges of new bone were formed between the hydroxyapatite particles and the cortical bone, 4 weeks after the injection of the HA particle-POP mixture. New bone formation was seen in all three tibiae at 8 weeks and thereafter. No new bone formation was observed in the tibiae of the control group. The affinity index, a parameter of osteogenesis, was 0% at 2 weeks, 52.2+/-14.0% at 4 weeks, 74.8+/-5.3% at 8 weeks, 86.1+/-6.1% at 12 weeks, 90.1+/-8.3% at 24 weeks and 92.8+/-4.1% at 40 weeks after injection. Statistically significant increases were found between the affinity indexes of 2 weeks and 4 weeks and between those of 4 weeks and 8 weeks, p < 0.03 and p < 0.05, respectively. Between 12, 24 and 40 weeks, the indexes showed tendencies toward increases. X-ray diffraction of bone marrow of two tibiae into which HA particle-POP mixture or POP alone was injected showed that POP had disappeared 8 weeks after injection.

Changes in osteosclerosis of the osteoarthritic knee after high tibial osteotomy.

Radiographically demonstrated osteosclerosis was quantitatively evaluated in knees with medial compartmental osteoarthritis by dual xray absorptiometry. Bone density was measured in various areas of 144 knees with medial compartmental osteoarthritis, 23 knees of which were treated with high tibial osteotomy. The bone mineral density of the medial femoral and tibial condyles was greater than that of the lateral femoral and tibial condyles in all knees with medial compartmental osteoarthritis. The ratios of bone mineral density of the medial condyles to that of the lateral condyles were found to increase significantly with the progression of osteoarthritis. There was a significant positive regression line correlation between those ratios and the increase of varus deformity as expressed by the standing femorotibial angle. The former were calculated to be 1.0 when the latter was nearly 170 degrees (10 degrees anatomic valgus angulation). The ratio of bone mineral density of the medial femoral condyles to the lateral femoral condyles decreased sharply in all 23 knees within 1 year after high tibial osteotomy.

Gradual low riding of the patella during postoperative course after total knee arthroplasty in osteoarthritis and rheumatoid arthritis

Patellar height in the lateral view of radiograms was measured on 94 knees of 61 women before and after total knee arthroplasty in order to study postoperative changes of position. The mean age of patients at surgery was 58.4 years (range, 30-77 years). Eighty-one knees were rheumatoid and 13 osteoarthritic. Inserted prostheses were Kinematic anteriorly joined type in 49 knees, Kinematic posterior cruciate retention type in 19, and UCI type in 26. The observation period ranged from 6 months to 9 years, with an average of 2.6 years after surgery. The ratio of length of the patellar ligament to that of the patella (Insall-Salvatis ratio) decreased by more than 10% of preoperative value in 61 knees, remained unchanged in 31, and increased in only 2. The average ratio was 0.93 +/- 0.16 before surgery and 0.75 +/- 0.20 at the final follow-up examination (P less than .01).

Effects of collagen gel mixed with hydroxyapatite powder on interface between newly formed bone and grafted Achilles tendon in rabbit femoral bone tunnel

The Achilles tendon was implanted into a bone tunnel made in the femoral condyle of 20 rabbits. In the left femur, collagen gel mixed with hydroxyapatite powder (C-HAp) was injected between the graft and the bone tunnel. On the other hand, as a control, simple saline was injected in the right femur. Five rabbits were sacrificed at 4, 8, 12, and 16 weeks after surgery. Histological findings showed that in the C-HAp group, the grafted tendon came in direct contact with new bone, and Sharpey-like collagen fibers arising from the grafted tendon were observed to penetrate new bone by 4 weeks after surgery. In the control group, however, fibrous tissue was observed between new bone and the grafted tendon, but no penetrating fibers from the grafted tendon into the new bone were observed until 16 weeks. The area of new bone in the C-HAp group was significantly greater than that in the control group 4, 8, and 12 weeks after surgery (p < 0.0001, p < 0.0007, p < 0.0013, respectively).

15-year follow-up study of total knee arthroplasty in patients with rheumatoid arthritis

In 25 patients with rheumatoid arthritis, 36 cases of cemented Kinematic total knee arthroplasty were reviewed clinically and radiographically at 13 to 19 years after surgery. The mean age at the time of surgery was 51.6 +/- 8.9 years. According to the follow-up results evaluated with the Hospital for Special Surgery knee scoring system, 28 knees (77.7%) were classified as good or excellent. The mean flexion angle at follow-up evaluation was 99 degrees +/- 24 degrees (10 degrees -140 degrees ). At the tibial or femoral bone-cement interfaces, a radiolucent line was seen in 10 of 36 knees (27.8%) at follow-up evaluation. The survival rate of prostheses with revision as the endpoint was estimated to be 93.7% at 15 years. Kinematic total knee arthroplasty in rheumatoid arthritis patients provided a good long-term outcome.

New bone formation around porous hydroxyapatite wedge implanted in opening wedge high tibial osteotomy in patients with osteoarthritis.

A porous hydroxyapatite (highly purified synthetic Ca10(PO4)6(OH)2) wedge was inserted into the tibia in 10 knees of 7 patients with osteoarthritis of the knee who underwent high tibial osteotomy. The interface of this HA wedge with bone was histologically examined in undecalcified specimens obtained at the time of hardware removal in all 10 knees, and total incorporation of the HA into bone was observed, with no inflammatory reaction. The proportion of pores that were filled with regenerated bone within 300 microm from the interface was 71.8 +/- 10.1% (mean +/- S.D.), and it was positively correlated with the time from implantation to biopsy. Radiodensity of the HA wedge was measured during the follow-up period, and it did not change significantly within 36 months after osteotomy. Our study concluded that bone ingrowth into the HA block slowly progressed and was correlated with the passage of time.