Masahiro Tatebe

Differentiation of transplanted mesenchymal stem cells in a large osteochondral defect in rabbit

BACKGROUND Although accumulating evidence shows that mesenchymal stem cells (MSC) are a promising cell source for articular cartilage repair, the fate of transplanted MSC has not been extensively studied. METHODS To monitor their persistence and differentiation, we labeled uninduced MSC with a fluorescent dye, PKH26, and transplanted them, in a poly-glycolic-acid scaffold, to full-thickness defects made in the weight-bearing area of rabbit femoral trochleae with hyaluronate sheets. The fate of the labeled cells was monitored for up to 8 weeks. RESULTS Two weeks after transplantation, immature cartilage containing collagen type II had formed. By 8 weeks, this cartilage had thinned and immunolabeling for collagen type II gradually disappeared from the basal region, which became positive for collagen type I. Most chondrocytes within the regenerated cartilage were PKH26-positive and, therefore, derived from transplanted MSC, whereas osteoblasts within the regenerated bone were a mixture of donor- and host-derived cells. The thickness of the cartilage became thinner up to 8 weeks and then remained stable up to 42 weeks after surgery. DISCUSSION These results showed that uninduced MSC were able to survive osteochondral defects and differentiated according to the environment, making a major contribution to initial cartilage formation and a partial contribution to bone regeneration.

Importance of distal radioulnar joint arthroscopy for evaluating the triangular fibrocartilage complex

BackgroundThe present study evaluated the importance of visualizing both sides of the triangular fibrocartilage complex (TFCC) when diagnosing ulnar wrist pain.MethodsA total of 20 patients with ulnar wrist pain who underwent both radiocarpal joint (RCJ) and distal radioulnar joint (DRUJ) arthroscopy were studied retrospectively. TFCC was graded as normal or as having wear or tear. The definitive diagnosis was made by evaluating the TFCC from both joints. The medical records were reviewed to document the preoperative diagnosis, arthroscopic findings, postoperative diagnosis, and operative procedure(s) performed after the arthroscopic examinations. The patients’ status at final follow-up was evaluated using the modified Green and O’Brien wrist scoring system. The TFCC grading on RCJ and DRUJ arthroscopies was compared.ResultsThe final diagnosis was modified after arthroscopic examination in three cases (15%). In six patients (30%), DRUJ arthroscopy revealed pathological TFCC findings that could not be detected on RCJ arthroscopy. The DRUJ arthroscopy detected wear or degenerative changes seen only on the proximal aspect of the TFCC in four patients and tear in two patients. On the other hand, in only one patient (5%) were there no pathological findings observed from the DRUJ portal, although RCJ arthroscopy found wear. In eight patients (45%), the arthroscopic grading of TFCC was the same on RCJ and DRUJ arthroscopy; of these, the TFCC was graded as normal in one patient, showing wear in three patients, and with a tear in five patients. For diagnosing TFCC pathology, RCJ arthroscopy had a sensitivity of 68% and a negative predictive value (NPV) of 14%, whereas the sensitivity was 95% and the NPV was 50% for DRUJ.ConclusionsAdding DRUJ arthroscopy to RCJ arthroscopy enables more accurate diagnosis of TFCC pathology because the proximal aspect of the articular disk and the foveal insertion of the distal radioulnar ligament can be visualized.

Clinical outcomes of corrective osteotomy for distal radial malunion: a review of opening and closing-wedge techniques.

BACKGROUND Radial corrective osteotomy is an established but challenging treatment for distal radial malunion. There is ongoing discussion over whether an opening or closing-wedge osteotomy should be employed. The purpose of the present study was to retrospectively compare the clinical and radiographic results of conventional opening-wedge osteotomy with those of our closing-wedge technique. METHODS We retrospectively evaluated forty-two patients with extra-articular distal radial malunion who were managed with corrective osteotomy and were followed for a minimum of one year. Twenty-two patients were managed with radial opening-wedge osteotomy and interpositional bone graft or bone-graft substitute, and twenty were managed with simultaneous radial closing-wedge and ulnar shortening osteotomy without bone graft. The selection of the surgical procedure was determined by the surgeon. Each patient was evaluated on the basis of objective radiographic measurements and functional outcomes as determined on the basis of clinical examination, including range of wrist motion, grip strength, pain-rating score, Mayo wrist score, and Disabilities of the Arm, Shoulder and Hand (DASH) score. RESULTS The mean duration of follow-up was thirty-six months (range, twelve to 101 months) for the opening-wedge cohort and twenty-eight months (range, twelve to eighty-seven months) for the closing-wedge cohort. The two techniques were comparable in terms of complications. Postoperative volar tilt and ulnar variance improved significantly compared with the preoperative status in each cohort (p < 0.05). Restoration of ulnar variance to within defined criteria (-2.5 to 0.5 mm) was significantly more frequent in the closing-wedge cohort than in the opening-wedge cohort (p < 0.001). The postoperative mean extension-flexion arc of the wrist (p < 0.001) and Mayo wrist score (p = 0.008) were significantly better in the closing-wedge cohort. Differences between the two cohorts in terms of the pronation-supination arc, grip strength, pain-rating score, and DASH scores were not significant. CONCLUSIONS The closing-wedge osteotomy technique is an effective reconstructive procedure for the treatment of extra-articular distal radial malunion. It is significantly better than the opening-wedge osteotomy technique in terms of the restoration of ulnar variance, the extension-flexion arc of wrist motion, and the Mayo wrist score.

Clinical, Radiographic, and Arthroscopic Outcomes After Ulnar Shortening Osteotomy: A Long-Term Follow-Up Study

PURPOSE Previous studies have investigated the long-term outcomes of ulnar shortening osteotomy (USO) in the treatment of ulnocarpal abutment syndrome (UCA), but none have used arthroscopic assessments. The purpose of this study was to investigate the long-term clinical outcomes of USO with patient-based, arthroscopic, and radiographic assessments. METHODS We retrospectively reviewed 30 patients with UCA after a minimum follow-up of 5 years, with arthroscopic evaluations at the time of both USO and plate removal. We confirmed the initial diagnosis of UCA by radiography and arthroscopy. Mean age at the time of index surgery was 37 years. Mean duration of follow-up was 11 years (range, 5-19 y). We obtained Disabilities of the Arm, Shoulder, and Hand and Hand20 self-assessments postoperatively for all patients. Bony spur formation was evaluated postoperatively from plain radiographs. RESULTS We detected triangular fibrocartilage complex (TFCC) disc tear in 13 wrists arthroscopically at the time of USO. Of these, 10 showed no evidence of TFCC disc tear at second-look arthroscopy. The remaining 17 cases showed no TFCC disc tear at either first- or second-look arthroscopy. Follow-up radiography revealed that bony spurs at the distal radioulnar joint had progressed in 13 wrists. Disabilities of the Shoulder, Arm, and Hand and Hand20 scores did not significantly correlate with the presence of bony spurs or TFCC disc tears. Range of motion decreased significantly with age only. Lower grip strength correlated with bony spur and lower radial inclination. Triangular fibrocartilage complex tear, male sex, and advanced age were associated with lower Disabilities of the Shoulder, Arm, and Hand and Hand20 scores. CONCLUSIONS Ulnar shortening osteotomy achieved excellent long-term results in most cases. Most TFCC disc tears identified at the initial surgery had healed by long-term arthroscopic follow-up. We suggest that UCA with a TFCC disc tear is a good indication for USO.

Fibroblast growth factor-2 enhances functional recovery of reinnervated muscle.

Long‐term denervation of muscles results in fibrosis and fat replacement, which prevent muscles from regaining contractile function despite reinnervation. Therefore, prevention of muscle atrophy between nerve repair and muscle reinnervation may improve the functional outcome. A variety of growth factors play significant roles in muscle mass modulation and muscle regeneration. The purpose of the present study was to investigate the effect of fibroblast growth factor‐2 (FGF2) and nerve growth factor (NGF) on muscle mass modulation after denervation and reinnervation using a nerve‐to‐muscle neurotization model. Growth factors were injected into the anterior tibial muscle after direct neurotization of muscles every 7 days up to 4 weeks after surgery. FGF2 significantly increased the amplitude of compound muscle action potentials (CMAPs), wet muscle weight, and the number of motor endplates, especially at higher concentration, compared to the vehicle. In contrast, NGF did not increase either the amplitude of CMAPs or muscle weight, although it significantly increased the number of motor endplates. These findings indicate that both growth factors enhance reinnervation of muscles; however, only FGF2 is involved in muscle mass modulation. Muscle Nerve, 2006

Sonography-guided Arthroscopy for Wrist Ganglion

PURPOSE To describe how to combine the complementary features of sonography and arthroscopy to make the arthroscopic resection of wrist ganglions a safer and more reliable surgery. METHODS A total of 22 patients with wrist ganglions had sonography-assisted arthroscopic resection. Sonographic visualization of ganglions, adjacent structures (ie, vessels, nerves, and tendons), and the cycling tip of the arthroscopic shaver was assessed. Arthroscopic visualization of the ganglions or ganglion stalk was also assessed. Clinical outcome measures included wrist range of motion, grip strength, and our patient-rated Hand 20 questionnaire. RESULTS Sonographic visualization of the ganglion stalk, adjacent structures, and the cycling tip of the arthroscopic shaver was possible in all 22 cases. However, ganglion stalks were visualized by arthroscopy in only 4 cases. The mean range of motion and grip strength were not significantly changed following surgery. However, the mean Hand 20 score was significantly improved from 17 to 6 at final follow-up. Ganglion recurrence was seen in 2 cases at 6 and 8 months after surgery. CONCLUSIONS Sonography-guided wrist arthroscopy provides several advantages for surgeons, including visualization of the ganglions and ganglion stalk, as well as of the arthroscopic shaver and adjacent structures such as nerves, vessels, and tendons to perform surgery safely.

Simple debridement has little useful value on the clinical course of recalcitrant ulnar wrist pain

The purpose of this study was to evaluate treatment results following arthroscopic triangular fibrocartilage complex (TFCC) debridement for recalcitrant ulnar wrist pain. According to the treatment algorithm, 66 patients (36 men and 30 women with a mean age of 38.1 years (15 to 67)) with recalcitrant ulnar wrist pain were allocated to undergo ulnar shortening osteotomy (USO; n = 24), arthroscopic TFCC repair (n = 15), arthroscopic TFCC debridement (n = 14) or prolonged conservative treatment (n = 13). The mean follow-up was 36.0 months (15 to 54). Significant differences in Hand20 score at 18 months were evident between the USO group and TFCC debridement group (p = 0.003), and between the TFCC repair group and TFCC debridement group (p = 0.029). Within-group comparisons showed that Hand20 score at five months or later and pain score at two months or later were significantly decreased in the USO/TFCC repair groups. In contrast, scores in the TFCC debridement/conservative groups did not decrease significantly. Grip strength at 18 months was significantly improved in the USO/TFCC repair groups, but not in the TFCC debridement/conservative groups. TFCC debridement shows little benefit on the clinical course of recalcitrant ulnar wrist pain even after excluding patients with ulnocarpal abutment or TFCC detachment from the fovea from the indications for arthroscopic TFCC debridement.

Regeneration of the perineurium after microsurgical resection examined with immunolabeling for tenascin-C and alpha smooth muscle actin

The regenerative process of the perineurium and nerve function were examined using an in vivo model of perineurium resection in the rat sciatic nerve. Our hypothesis is that the regenerative process of the perineurium can be demonstrated by immunolabeling for tenascin‐C and alpha smooth muscle actin after microsurgical resection of the perineurium in vivo. A total of 38 Lewis rats were used. Eight‐week‐old animals were assigned to one of two groups: the epi‐perineurium removal group or the sham group. Under operative microscopy, the sciatic nerve was dissected from surrounding tissues at the thigh level from the ischial tuberosity to the fossa poplitea. The epi‐perineurium was carefully removed by cutting circumferentially and stripping distally for 15 mm. For CatWalk® dynamic gait analysis, only right sciatic nerves underwent surgery; the left sciatic nerves were left intact. For pathological and electrophysiological tests, both the right and left sciatic nerves underwent surgery. Analysis of data was performed at each time interval with a two‐group t‐test. P < 0.05 was considered statistically significant. After resection of a 15‐mm section of the epi‐perineurium, immediate endoneurial swelling occurred in the outer portion and spread into the central portion. Although demyelination and axonal degeneration were found in the swollen area, remyelination and recovery of electrophysiological function were seen after regeneration of the perineurium. An immunohistological and electron microscopic study revealed that the perineurium regenerated via fusion of the residual interfascicular perineurium and endoneurial fibroblast‐like cells of mesenchymal origin. CatWalk gait analysis showed not only motor paresis but also neuropathic pain during the early phases of this model.

Limited wrist arthrodesis versus radial osteotomy for advanced Kienböck's disease--for a fragmented lunate.

Thirty-eight patients with advanced Kienböcks disease treated by limited wrist arthrodesis (LWA: n = 10) or radial osteotomy (RO: n = 28) for a fragmented lunate were retrospectively examined after an average of 47.9 and 68.1 months, respectively. Compared with pre-operative values, the active flexion-extension range of motion decreased by about 16.0 degrees in LWA and increased approximately 9.7 degrees in RO and the grip strength improved by approximately 7.5 kg in LWA and 8.0 kg in RO. In both groups, radiographs showed no significant progression of carpal collapse. Although LWA caused some decrease in wrist flexion-extension, both procedures are appropriate for surgical treatment of advanced Kienböcks disease. Most patients experienced a reduction in pain and were able to return to work.

Cubital tunnel syndrome caused by amyloid elbow arthropathy in long-term hemodialysis patients: report of 4 cases.

Carpal tunnel syndrome occurs frequently in long-term hemodialysis patients. However, the literature contains few detailed reports of other nerve entrapment syndromes of the upper extremity in these patients. We encountered 4 cases in which cubital tunnel syndrome occurred in long-term hemodialysis patients. In all cases, a hypertrophic synovial mass projecting from the humeroulnar joint compressed the ulnar nerve, and Congo red staining revealed that the mass contained amyloid deposition. Synovial proliferation resulting from amyloid arthropathy of the elbow joint appears to be the primary cause of this disease.