Shogo Mukai

Simultaneous stimulation of EP2 and EP4 is essential to the effect of prostaglandin E2in chondrocyte differentiation

OBJECTIVE Prostaglandin E(2)(PGE(2)) has been reported to stimulate chondrocyte differentiation. However, the precise actions and signal transduction pathways of PGE(2)in cartilage are largely unknown. Our purpose is to identify which of the four PGE(2)receptor subtype(s), EP1-4, mediates the action of PGE(2)on chondrocyte differentiation. DESIGN We used primary chondrocytes derived from the resting zone of rat rib cartilage. The effects on chondrocyte differentiation were assessed by measuring the Alcian blue-stainable proteoglycan content and the expression levels of type II collagen mRNA by Northern blot analysis. The expression of the four PGE(2)receptor subtypes in rat primary chondrocytes was examined by reverse transcription-polymerase chain reaction. RESULTS PGE(2)stimulated the accumulation of proteoglycan and up-regulated the expression of type II collagen mRNA in primary chondrocytes. Dibutyryl cAMP, a cell-permeable analog of cAMP, an important intracellular mediator of PGE(2)signaling, also enhanced the expression of type II collagen mRNA and proteoglycan accumulation in chondrocytes. No EP agonist alone induced the expression of type II collagen mRNA. However, simultaneous administration of EP2 and EP4 agonists at high concentrations cooperatively induced the expression of type II collagen mRNA, mimicking the PGE(2)effect. The simultaneous stimulation of EP2 and EP4 also cooperatively enhanced proteoglycan accumulation and intracellular cAMP production. Moreover, an EP4 antagonist partially blocked the stimulatory actions of PGE(2)on the expression of type II collagen mRNA. CONCLUSION These results suggest that simultaneous stimulation of EP2 and EP4 is necessary and sufficient to elicit the effect of PGE(2)on rat primary chondrocyte differentiation.

Osteochondral autograft transplantation for isolated patellofemoral osteoarthritis

BACKGROUND The purpose of this retrospective study was to evaluate clinical outcomes of osteochondral autograft transplantation (OAT) for isolated patellofemoral (PF) osteoarthritis (OA). METHODS OAT was performed in seven patients (six men, one woman; mean age, 61.1years) with isolated PF OA. The mean duration of follow up was 46.9months (range, 24-84months). Clinical outcomes were evaluated preoperatively and postoperatively according to the International Knee Documentation Committee (IKDC) objective score and the knee scoring system of the Japanese Orthopaedic Association (JOA) score. The International Cartilage Repair Society (ICRS) score was recorded in three cases that underwent second-look arthroscopies postoperatively. For morphological evaluation, the Kellgren and Lawrence (KL) classification and the modified magnetic resonance observation of cartilage repair tissue (MOCART) score were used. RESULTS The mean IKDC and JOA scores were both significantly improved. The percentage of normal and nearly normal on the IKDC score was increased from 28.6% (2/7) to 85.7% (6/7) (P=0.05). The mean JOA score was improved from 80.0 (range, 65.0-85.0) to 95.0 (range, 90.0-100) (P=0.0008). The mean ICRS scores were 10.3 (nearly normal) in the three cases that underwent second-look arthroscopies postoperatively. Regarding KL classification, the grade was unchanged in five cases (two cases in grade 1, three cases in grade 2) and improved in two cases (from grade 3 to 2, from grade 4 to 3). The mean modified MOCART score was 67.9 (range, 60.0-75) at 12-month follow up. There were no complications, and satisfaction was obtained in all cases. The study design was case series: level IV. CONCLUSIONS All clinical scores improved significantly postoperatively. Osteochondral plugs were transplanted perpendicular to the articular surface to obtain good congruity of the repaired articular surface. In this way, OAT is an effective procedure to prevent progression of isolated PF OA.

Serial Changes of the Cartilage in Recipient Sites and Their Mirror Sites on Second-Look Imaging After Mosaicplasty:

Background: It has been reported that the short-term results of mosaicplasty are good, but there have been no reports of the serial cartilage changes in the recipient sites and their mirror sites for mosaicplasty. Purpose: To examine the serial changes in cartilage in the recipient sites and their mirror sites using second-look imaging. Study Design: Case series; Level of evidence, 4. Methods: A total of 33 patients (37 knees, 40 sites) underwent mosaicplasty and second-look arthroscopy at a single institution over a 7-year period. There were 14 men and 19 women (12 right knees and 25 left knees). The recipient sites were the patella (n = 3), trochlea (n = 7), medial femoral condyle (n = 21), and lateral femoral condyle (n = 9). The mean patient age at surgery was 38.3 years; the mean period from mosaicplasty to second-look arthroscopy was 15.4 months; and the mean follow-up period was 34.9 months (range, 24-65 months). The results of second-look arthroscopy at the recipient site were categorized as cartilage with a smooth surface (group S) and fibrillation or an irregular surface (group I), and results of second-look arthroscopy at the mirror site were categorized as worse (group W), improved (group E), and unchanged (group U). Results: There were 30 sites in group S, 10 sites in group I, 3 sites in group W, 4 sites in group E, and 33 sites in group U. The age at operation was significantly greater in group S than in group I. There was a significant correlation between group S and groups E and U. The clinical outcome was significantly worse in group W when compared with groups E and U. Conclusion: If a smooth surface was seen in the recipient site during second-look arthroscopy, the cartilage degeneration in its mirror site did not become worse after mosaicplasty.

Cartilage Degeneration and Alignment in Severe Varus Knee Osteoarthritis

Objectives The aim of this study was to examine the relationship between cartilage, ligament, and meniscus degeneration and radiographic alignment in severe varus knee osteoarthritis in order to understand the development of varus knee osteoarthritis. Design Fifty-three patients (71 knees) with primary varus knee osteoarthritis and who underwent total knee arthroplasty were selected for this study. There were 6 men and 47 women, with 40 right knees and 31 left knees studied; their mean age at operation was 73.5 years. The ligament, meniscus, degeneration of joint cartilage, and radiographic alignments were examined visually. Results The tibial plateau–tibial shaft angle was larger if the condition of the cartilage in the lateral femoral condyle was worse. The femorotibial angle and tibial plateau–tibial shaft angle were larger if the conditions of the lateral meniscus or the cartilage in the lateral tibial plateau were worse. Conclusion Based on the results of this study, progression of varus knee osteoarthritis may occur in the following manner: medial knee osteoarthritis starts in the central portion of the medial tibial plateau, and accompanied by medial meniscal extrusion and anterior cruciate ligament rupture, cartilage degeneration expands from the anterior to the posterior in the medial tibial plateau. Bone attrition occurs in the medial tibial plateau, and the femoro-tibial angle and tibial plateau–tibial shaft angle increase. Therefore, the lateral intercondylar eminence injures the cartilage of the lateral femoral condyle in the longitudinal fissure type. Thereafter, the cartilage degeneration expands in the whole of the knee joints.

Ultrasound Parameters for Human Osteoarthritic Subchondral Bone ex Vivo: Comparison with Micro-Computed Tomography Parameters

The aim of this study was to identify ultrasound parameters reflecting subchondral porosity (Po), subchondral plate thickness (Tpl) and bone volume fraction at the trabecular bone region (BV/TVTb). Sixteen osteoarthritic human lateral femoral condyles were evaluated ex vivo using a 15-MHz pulsed-echo ultrasound 3-D scanning system. The cartilage-subchondral bone (C-B) surface region (layer 1) and inner subchondral bone region (layer 2) were analyzed; we newly introduced entropy (ENT) and correlation (COR) of ultrasound texture parameters of the parallel (x) or perpendicular (z) direction to the C-B interface for this analysis. Po, Tpl and BV/TVTb were evaluated as reference measurements using micro-computed tomography. ENTL1x (ENT of layer 1, x-direction) and ENTL1z were significantly correlated with Po (both r values = 0.58), CORL2x with Tpl (r = -0.73) and CORL2z with BV/TVTb (r = -0.66). These are efficient indicators of the characteristics of osteoarthritis-related subchondral bone; the other texture parameters were not significant.

The clinical outcomes and the ability to sit straight in the Japanese style following high tibial osteotomy combined with osteochondral autologous transfer for osteonecrosis of the medial femoral condyle

BACKGROUND There have been some reports of high tibial osteotomy combined with osteochondral autograft transfer for osteonecrosis of the medial femoral condyle of the knee. However, few of them have focused on the deep knee flexion needed to sit straight in the Japanese style. PURPOSE To evaluate the clinical outcomes and the knee flexion of HTO combined with OAT for osteonecrosis of the medial femoral condyle of the knee, especially the ability to sit straight in the Japanese style. METHODS Between 1998 and 2012, valgus HTO combined with OAT was performed in 23 patients for stage IV osteonecrosis according to Koshinos radiological classification of the medial femoral condyle. The follow-up period was more than 2 years in all cases. The mean age at the time of the surgery was 65.8 years, and the mean follow-up period was 72.2 months. The function of the knee and the ability to sitting straight in the Japanese style were examined. Twenty-one knees were examined with second-look arthroscopy to assess the recipient and donor sites. RESULTS The JOA scale and IKDC subjective scores were significantly improved. Twelve patients were able to sit straight in the Japanese style after the surgery, compared to 3 patients who were able to do so before surgery. On second-look arthroscopy of 21 knees, the average ICRS score was 10.5 points. No patient needed additional surgery except for removal of the implants. CONCLUSION Valgus HTO combined with OAT is one treatment option for osteonecrosis of the medial femoral condyle with osteoarthritis. In the present study, many of the patients regained good knee function, and 50% of the patients were able to sit straight in the Japanese style after surgery, which is a higher rate than after total knee arthroplasty and unilateral knee arthroplasty.

Resection-Induced Leveling of Elevated Plug Cartilage in Osteochondral Autologous Transplantation of the Knee Achieves Acceptable Clinical Results

Background: Plug protuberance occasionally occurs in osteochondral autologous transplantation (OAT). The incongruity of plugs results in poor clinical outcomes, especially in cases of protuberance. However, a surgical procedure to deal with this problem has not been reported. Purpose/Hypothesis: The purpose was to evaluate the efficacy and safety of cartilage resection of elevated plugs, with the hypothesis that patients whose elevated plugs were resected and leveled would achieve clinical outcomes equivalent to those of patients with flush plugs. Study Design: Cohort study; Level of evidence, 3. Methods: Cases (group P) included 22 patients who underwent OAT of the knee and whose plugs showed protuberance greater than 1 mm that was resected with a scalpel to obtain smooth congruity, while controls (group C) included 22 background-matched patients who did not require plug resection. The International Knee Documentation Committee (IKDC) subjective score, IKDC objective grade, and Japanese Orthopaedic Association score for knee osteoarthritis (JOA knee score) were used preoperatively and at the final follow-up (mean ± SD, 49.3 ± 18.1 months). International Cartilage Repair Society (ICRS) Cartilage Repair Assessment was used to evaluate lesion healing during the second-look arthroscopy. Results: IKDC subjective scores of group C (82.5 ± 11.8) and group P (82.1± 15.1) showed no difference at the final follow-up. On postoperative IKDC objective grading, 86% of group C and 82% of group P patients were graded as “nearly normal” or better (P = .639). The mean JOA knee scores of group C (90.9 ± 8.9) and group P (90.1 ± 9.5) did not differ significantly (P = .647). Nine second-look arthroscopies were performed in group C versus 8 in group P, and all patients had plugs that were graded as “nearly normal” or better by the ICRS Cartilage Repair Assessment. Larger plugs tended to be used in those patients who required resection. Conclusion: Resection of the elevated plug surface did not negatively affect patient outcomes in the midterm follow-up period.

Clinical Outcomes of Donor Sites After Osteochondral Graft Harvest From Healthy Knees

Background: The use of autologous osteochondral grafts has become popular in the treatment of small, isolated, well-contained articular cartilage defects. However, donor site morbidity is a problem, and few reports are available of donor site morbidity after mosaicplasty. Purpose: To examine the clinical outcomes of donor sites after osteochondral grafts from healthy knees. Study Design: Case series; Level of evidence, 4. Methods: Between September 1997 and September 2011, there were 40 patients (40 knees; 32 men, 8 women; 31 right knees, 9 left knees) with asymptomatic osteochondral graft donor sites used for autologous transfer; all had a follow-up period of >2 years. The mean patient age at surgery was 21.0 years (range, 12-58 years). The recipient sites included the elbow (n = 28), contralateral knee (n = 5), and ankle (n = 7). The mean diameter of the grafted plugs was 7.5 mm (range, 4.5-9 mm), and the mean number of grafted plugs was 2.2 (range, 1-3). At a mean follow-up of 43.1 months (range, 24-177 months), knee symptoms, return to sport, ability to sit straight in Japanese style, and radiological changes of the patellofemoral joint were evaluated. Whether operative age, follow-up period, and diameter or number of the grafted plugs were risk factors was analyzed statistically. Significance was defined as P < .05. Results: Thirty-four patients had no knee symptoms, and 4 patients had occasional mild knee pain. Two patients underwent reoperation for arthrofibrosis and not for cartilage defect. Twenty-seven patients had complete return to sports, and 32 patients could sit straight; donor site morbidity was not the cause of failure to return to sports or inability to sit straight. The radiological changes became worse in 3 patients, and the risk factor for degenerative change was older operative age. Conclusion: When osteochondral plugs were obtained from healthy knees, 34 patients (85%) were asymptomatic at follow-up. No donor site defects required surgical intervention due to persistent symptoms.

Radiological Changes in the Cervical Spine in Freshman Collegiate Sumo Wrestlers

Background: Sumo has long been a traditional sport in Japan and is rapidly attracting enthusiasts abroad. Sumo wrestling entails a risk of impact to the cervical spine during an initial charge. Few reports are available in the English-language literature regarding radiological changes in the cervical spine in sumo wrestlers. Purpose: To examine radiological changes in the cervical spine in freshmen collegiate sumo wrestlers. Study Design: Case series; Level of evidence, 4. Methods: A total of 53 freshmen sumo wrestlers (age, 18-19 years) who belonged to the Japan Sumo Federation underwent routine radiographic examination of the cervical spine and completed questionnaires on cervical symptoms. Results: Of the 53 wrestlers, 81% showed loss of lordosis, 45% showed osteophyte formation (mainly at C3-C4), 11% showed disc space narrowing (mainly at C5-C6), and 51% showed narrowing of the cervical nerve root foramina (mainly at C3-C4). Fifty-one percent had some cervical symptoms. A correlation was found between deformity of the cervical bodies (such as intervertebral disc ballooning) and cervical symptoms, but no correlation was found between cervical degenerative changes and cervical symptoms. Conclusion: Our data suggest that loss of lordosis, osteophyte formation, and narrowing of the cervical nerve root foramina at C3-C4 were frequently present in freshmen wrestlers and may be due to the axial load incurred prior to their collegiate careers.