Koichi Nakagawa

Deterioration of long-term clinical results after the Elmslie-Trillat procedure for dislocation of the patella

We examined 39 patients (45 knees) who had undergone an Elmslie-Trillat procedure for recurrent or habitual dislocation of the patella with a follow-up of more than ten years. The mean age at the time of surgery was 18.4 years; the mean follow-up was 161 months (120 to 238). Using Fulkersons functional knee score, 41 knees (91%) had an excellent or good result at a mean follow-up of 45 months, and this was maintained in 29 (64%) at the final review. The main cause of deterioration in the clinical results was the onset or worsening of patellofemoral joint pain, not patellar instability.

Existence of a Neuropathic Pain Component in Patients with Osteoarthritis of the Knee

Purpose Pain from osteoarthritis (OA) is generally classified as nociceptive (inflammatory). Animal models of knee OA have shown that sensory nerve fibers innervating the knee are significantly damaged with destruction of subchondral bone junction, and induce neuropathic pain (NP). Our objective was to examine NP in the knees of OA patients using painDETECT (an NP questionnaire) and to evaluate the relationship between NP, pain intensity, and stage of OA. Materials and Methods Ninety-two knee OA patients were evaluated in this study. Pain scores using Visual Analogue Scales (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), painDETECT, duration of symptoms, severity of OA using the Kellgren-Lawrence (KL) system, and amount of joint fluid were evaluated and compared using a Spearmans correlation coefficient by rank test. Results Our study identified at least 5.4% of our knee OA patients as likely to have NP and 15.2% as possibly having NP. The painDETECT score was significantly correlated with the VAS and WOMAC pain severity. Compared with the painDETECT score, there was a tendency for positive correlation with the KL grade, and tendency for negative correlation with the existence and amount of joint fluid, but these correlations were not significant. Conclusion PainDETECT scores classified 5.4% of pain from knee OA as NP. NP tended to be seen in patients with less joint fluid and increased KL grade, both of which corresponded to late stages of OA. It is important to consider the existence of NP in the treatment of knee OA pain.

Risedronate decreases bone resorption and improves low back pain in postmenopausal osteoporosis patients without vertebral fractures.

Elderly postmenopausal women who have osteoporosis sometimes experience low back pain, however, the relationship between low back pain and osteoporosis in the absence of vertebral fractures remains unclear. We examined the relationship between bone mineral density (BMD), bone resorption and low back pain in elderly female patients who did not have osteoporotic vertebral fractures. The average BMD was 0.675 g/cm(2) when assessed by dual-energy X-ray absorptiometry (DEXA). Patients were excluded from the study if they had vertebral fractures revealed by radiography, CT scans or MRI. Bisphosphonate (risedronate) was administered for 4 months. The visual analogue scale (VAS) pain score, Roland Morris Disability Questionnaire (RDQ), Short Form-36 (SF-36) questionnaire, BMD and N-terminal telopeptide of type I collagen (NTx; a marker for bone resorption) were examined before and after treatment. DEXA did not increase significantly, but serum and urinary NTx were decreased (-51.4% and -62.0%, respectively) after 4 months of risedronate treatment (p<0.01). The assessment was repeated using the VAS score, RDQ and SF-36, which revealed an improvement after risedronate treatment (p<0.01). A decrease in serum and urinary NTx was associated with improvement of low back pain, suggesting that despite the absence of vertebral fractures, bone resorption due to osteoporosis may cause low back pain.

Detection of pain-related molecules in the subchondral bone of osteoarthritic knees

Knee pain is predominant among osteoarthritis (OA) patients, but the mechanism is poorly understood. We investigated subchondral bone as a source of OA knee pain using immunohistochemistry. Fifteen medial-type OA knees with minimum involvement of the lateral compartment determined by X-ray as well as magnetic resonance imaging that received total knee arthroplasty (TKA) were involved. Each pair of the medial femoral condyle (MFC) and lateral femoral condyle (LFC) was compared obtained at the time of TKA. Osteocartilaginous MFC and LFC specimens were histologically examined and stained with antibodies against cyclooxygenase 1 (Cox-1), cyclooxygenase 2 (Cox-2), substance P, tumor necrosis factor-alpha (TNF-α), and neuron-specific class III beta-tubulin (TUJ1), a pan-neuronal marker. Formation of cystic lesions was more frequently seen in the MFC. The lesions were composed of vascular endothelial cells, osteoclasts, and mononuclear cells and were present in similar proportions between the MFC and the LFC. Four out of 15 MFC specimens were positive for Cox-1, 15 for Cox-2, and 13 for TNF-α. No LFC specimens were positive for any antibodies. Substance P-positive and TUJ1-positive fibers were found in the subchondral area of the MFC, but not in the LFC. Pathological changes in the subchondral bone can be a source of knee pain, which was detectable by the positive immunoreactivity of substance P, Cox-2, TNF-α, and TUJ1, in the subchondral bone of affected compartments. The relatively immediate reduction in pain obtained by TKA might account for the involvement of the subchondral bone in knee pain because most of the affected subchondral plate is excised in TKA (debridement effect of TKA).

Lateral Laxity in Flexion Increases the Postoperative Flexion Angle in Cruciate-Retaining Total Knee Arthroplasty

Thirty-eight patients diagnosed with osteoarthritis underwent 41 cruciate-retaining total knee arthroplasties. In varus and valgus tests at flexion, subjects were seated on a table at 80° of knee flexion; 50 N was applied perpendicular to the lower leg. The factors affecting the postoperative flexion angle were investigated in a multiregression analysis. The mean joint angles of the flexion-valgus and flexion-varus tests were 3.4° ± 1.4° and 6.2° ± 2.5°, respectively. The flexion-varus angle was correlated with the postoperative flexion angle (P < .01). The mean postoperative flexion angles were 110.8° ± 9.6° and 118.1° ± 8.0° in the groups with the flexion-varus angle of 6° or less and more than 6°, respectively (P = .02). Slack lateral laxity in flexion had a significant effect during knee flexion in cruciate-retaining total knee arthroplasty.

RGD peptide-induced cell death of chondrocytes and synovial cells

BackgroundSmall peptides including the Arg-Gly-Asp (RGD) motif have been used in studies on cell-extracellular matrix (ECM) attachment due to their ability to disturb integrin-mediated attachment on the cell surface. As another biological action of RGD peptides, several reports have shown that RGD peptides are incorporated into cytoplasm and induce apoptosis by direct activation of caspase-3. This study evaluated the effect of RGD peptides on chondrocytes and synovial cells and studied the involvement of caspases.MethodsChondrocytes and synovial cells were isolated and cultured from the knee joints of New Zealand White rabbits. Cells were incubated in serum-free medium with peptides (RGD, RGDS, GRGDSP, GRGDNP, RGES), and the survival rates were evaluated. The rate of apoptotic cells was measured by flow cytometry in cells treated with RGDS, GRGDSP, and RGES. Caspase-3, -8 and -9 activity was measured in cells treated with RGDS and GRGDSP. Osteochondral explants harvested from rabbits were also incubated with RGD peptides (RGDS, GRGDSP, and GRGDNP), and the survival rate of chondrocytes was evaluated.ResultsThe survival rate of cultured chondrocytes was significantly decreased in the GRGDSP- and GRGDNP-treated groups. The survival rate of synovial cells was significantly decreased with four of the RGD peptides (RGD, RGDS, GRGDSP, and GRGDNP) at 5 mM, and in the RGDS- and GRGDSP-treated groups at 1 mM. Flow cytometric assay revealed increases of apoptotic chondrocytes with GRGDSP and increases of apoptotic synovial cells with RGDS and GRGDSP. Caspase-3 was activated in chondrocytes treated with GRGDSP and it was also activated in synovial cells treated with RGDS and GRGDSP. Caspases-8 and -9 were not activated in chondrocytes or in synovial cells. The survival rate of chondrocytes in explants decreased in the superficial layer with all three RGD peptides (RGDS, GRGDSP, and GRGDNP) and in the middle layer with GRGDSP.ConclusionsRGD peptides induced apoptosis in cultured chondrocytes as well as in cells in cartilage explants and synovial cells, presumably through direct activation of caspase-3.

In vivo 3D kinematics of normal forearms: Analysis of dynamic forearm rotation

BACKGROUNDnForearm rotation is an indispensable activity of daily living and comprises complex motions with rotational and translational components. It is thought that changes in these motions with injury or disease may affect diagnostic indices. Several studies have assessed in vivo forearm kinematics with static conditions, but dynamic forearm kinematics have not yet been reported. The purpose of this study was to analyze forearm kinematics during dynamic rotation using radiographic 3D-2D registration methods.nnnMETHODSnTen forearms of five healthy males with the mean age of 37 years old were enrolled. Lateral fluoroscopic images were taken during forearm rotation from maximum supination to maximum pronation with their elbows flexed to approximately 45°. Geometric bone models were created from CT scans of the humerus, the radius and the ulna. Three-dimensional kinematics were determined using 3D-2D model registration techniques with the images and models, and the arc of axial rotation of the radius, volar/dorsal translation of the ulna at the distal radioulnar joint and rotation axis of forearm were computed.nnnFINDINGSnThe radial rotation arc was 157°. The ulna translated 3.9 mm (SD 1.5mm) dorsally during activity. The rotation axis of the forearm passed through the center of the radial head and the ulnar head at the 1.9 mm (SD 0.7 mm) posterior from its geometric centroid.nnnINTERPRETATIONnThe posteriorly deviated rotation axis at the ulnar head may result in the ulnar head translating dorsally during pronation. These data provide a basis for objective assessment of pathological forearm function.

Degeneration and Recovery of the Neuromuscular Junction after Application of Extracorporeal Shock Wave Therapy

It is known that free nerve endings are degenerated after application of shock waves. We therefore hypothesized that the application of shock waves to muscle induces dysfunction of neuromuscular transmission at neuromuscular junctions. We investigated changes in neuromuscular transmission in response to shock wave application. Sprague–Dawley rats were used in this study. Two thousand shock waves at an energy flux density of 0.18u2009mJ/mm2 were applied to their right calf muscles. Neuromuscular junctions of gastrocnemius muscles were evaluated using rhodamine–α‐bungarotoxin on the day of treatment (nu2009=u20095). Amplitude and latency of compound muscle action potentials were measured on the day of treatment and 1, 2, 4, 6, and 8 weeks after treatment (nu2009=u200910, each group). Degenerated acetylcholine receptors existed in all treated muscles. Although the action potential amplitude on the treated side was significantly less than on the control side from the day of treatment (25.1u2009±u20097.8 vs. 34.5u2009±u20099.1, pu2009=u20090.012) to 6 weeks (27.9u2009±u20097.2 vs. 34.5u2009±u20097.2, pu2009=u20090.037), there was no significant difference at 8 weeks. There was no significant difference in transmission latency between the groups. The application of shock waves to muscle induced a transient dysfunction of nerve conduction at neuromuscular junctions.

Two cases of synovial haemangioma of the knee joint: Gd-enhanced image features on MRI and arthroscopic excision

Synovial haemangioma of the knee joint is a relatively rare benign condition with around 200 reported cases. We have recently encountered two cases of synovial haemangioma of the knee joint which preoperative MRI had assessed as highly suspect and which arthroscopic resection and subsequent histological examinations confirmed as synovial hemangiomas. Published studies have identified the following as characteristic MRI features of synovial haemangioma: homogenous low intensity to iso-intensity on T1 sequence; and heterogeneous high intensity with low-intensity septa or spots within the lesion on T2 sequence. However, several other intra-knee disorders mimic these characteristics. In our two cases, we found that gadolinium (Gd)-enhanced images, which have been relatively rarely discussed in the literature, were useful for making the diagnosis and for determining the extent of this condition. These images also were very helpful during arthroscopic excision of the lesion. Nonetheless, even after Gd enhancement, differentiating between malignant conditions such as synovial sarcoma and haemangioma solely from MRI findings is still difficult.

Spontaneous Recurrent Hemarthrosis of the Knee in the Elderly: Arthroscopic Treatment and Etiology

PURPOSEnTo elucidate the etiology of and find a preferable surgical treatment for spontaneous recurrent hemarthrosis in osteoarthritic knee joints arthroscopically.nnnMETHODSnNineteen patients referred to our institution from affiliate hospitals between April 1998 and October 2006 were involved in this study. Their demographics, preoperative radiographic findings, preoperative magnetic resonance imaging (MRI) findings, arthroscopic findings and procedures performed, the patients medical history, and the postoperative clinical course were retrospectively reviewed.nnnRESULTSnThere were 9 male and 10 female patients with average age of 61.9 years (range, 41 to 83 yrs). The average number of joint aspirations before surgery was 5.4. The average time from onset to arthroscopy was 10 months. Radiographs showed 2 knees with isolated lateral compartment osteoarthritis (OA), one with isolated patellofemoral (PF) OA, 14 with medial and lateral compartment OA, and 2 with tricompartmental OA. Classifying them according to the dominant compartment, 6 knees were medial-dominant OA, 11 lateral-dominant OA, and 2 PF-dominant OA. The MRI scans revealed 18 grade III lateral menisci and 1 grade II lateral menisci. Even with 6 medial-dominant OAs, lateral meniscal involvement was more obvious than medial meniscal involvement on MRI. Subtotal lateral meniscectomy accompanied with coagulation of the bleeding points was performed on 17 cases. For 2 PF OA cases, synovectomy and a histologic examination of synovium were performed. Remission was obtained for 18 cases. The unsuccessful case had cirrhosis of the liver.nnnCONCLUSIONSnA majority of the patients (17 of 19) had degenerative torn lateral menisci confirmed with MRI and at arthroscopy. Successful outcomes were achieved by meniscectomy and coagulation. Most so-called spontaneous recurrent hemarthroses in OA knee joints appear to be attributable to torn lateral menisci.nnnLEVEL OF EVIDENCEnLevel IV, therapeutic case series.