Healing Effect of Subcutaneous Administration of Granulocyte Colony-Stimulating Factor on Acute Rotator Cuff Injury in a Rat Model.

Granulocyte colony-stimulating factor (G-CSF) is a cytokine that mobilizes bone marrow-derived cells (BMDCs) to peripheral blood and has been clinically used to treat neutropenia. Previously, we reported that BMDCs migrated into the rotator cuff repair site via peripheral blood in the healing process. However, techniques to accelerate the healing process using the peripheral blood pathway have not been established. We evaluated whether G-CSF has a noteworthy effect on improving rotator cuff healing by enhancing the influx of BMDCs into the peripheral blood. We used Sprague-Dawley rats and chimeric rats, selectively expressing green fluorescent protein (GFP) in BMDCs. Their bilateral supraspinatus tendons were resected and sutured to the greater tuberosity of the humerus using the Masson-Allen technique, and G-CSF was subcutaneously injected for 5 days after surgery. Several GFP-positive cells were observed around the enthesis in the G-CSF-treated group compared with that in the Control group. Histological analysis revealed that the tendon-to-bone maturing scores and the Safranin O-stained cartilaginous areas were significantly higher in G-CSF-injected rats than in the control rats at weeks 4 and 8 after surgery. Consistently, the ultimate force to failure in the G-CSF-treated group significantly increased compared with the Control group at weeks 4 and 8 after surgery. These results suggest that BMDCs mobilized into the peripheral blood after G-CSF administration migrated to the rotator cuff repair area and effectively enhanced rotator cuff healing by promoting tenocyte and cartilage matrix production. In conclusion, the BMDC mobilization technique by G-CSF treatment via peripheral blood will provide a potential therapeutic approach for rotator cuff healing with clinically relevant applications. Impact statement As the retear rate following rotator cuff repair is high, new methods to aid its healing are required. Granulocyte colony-stimulating factor (G-CSF) has been used clinically and may represent a novel approach to treating rotator cuff tear. Herein, using a rat model, we elucidate the kinetics of bone marrow-derived mesenchymal stem cells at the repair site following G-CSF administration and describe the underlying mechanism by which G-CSF can help promote the repair of the rotator cuff.

Cryptococcal Osteomyelitis of the Entire Humerus: A Case Report.

CASE: We describe a case of cryptococcal osteomyelitis in a 70-year-old man who presented with left elbow and shoulder pain. Subsequent imaging indicated osteomyelitis of the entire humerus, and he underwent debridement of the elbow and shoulder. Pathological findings revealed Cryptococcus neoformans infection. Surgical management was followed by a prolonged course of antibiotics. CONCLUSION: Although C. neoformans is rare as the etiology of infection of the entire humerus, orthopaedic surgeons should consider cryptococcosis as a potential cause of infection.

Intracerebral hemorrhage due to cerebral venous thrombosis during posterior cervical decompression and fusion for traumatic cervical cord injury: A case report.

RATIONALE: Cerebral venous thrombosis (CVT) is a cerebrovascular disorder that causes venous infarction and intracerebral hemorrhage (ICH) with occlusion of cerebral veins, and its incidence is estimated to be 5 per 1 million people per year, accounting for 0.5% to 1.0% of all strokes. Despite advances in the recognition of CVT, the diagnosis and treatment may be difficult because of the diversity of underlying risk factors. A rare case of ICH due to CVT during surgery is described. PATIENT CONCERNS: A 69-year-old-man presented to our department with a history of paralyzed extremities after a backward fall and head trauma. The patient had a history of pharyngeal cancer treated with neck dissection and radiotherapy. Computed tomography (CT) images showed continuous ossification of the posterior longitudinal ligament (OPLL) at C2-5 levels and a fracture line at the caudal end plate of the C5 body. The diagnosis was traumatic cervical cord injury, so that posterior cervical decompression and fusion was performed. Immediately after surgery, the patient developed an epileptic seizure and the disturbance of consciousness persisted. MR venography and contrast CT images showed absence of flow from the superior sagittal sinus to the transverse sinus. DIAGNOSES: The diagnosis in this case was ICH due to CVT. INTERVENTIONS: The patient was treated with anticoagulation using unfractionated heparin. OUTCOMES: The patient ultimately made a complete recovery from CVT. LESSONS: Although risk factors for CVT are diverse, head and neck injury, patient's position during surgery, and postoperative radical neck dissection for pharyngeal cancer might have been the factors in this case. While the measures to prevent this disease are uncertain, early diagnosis and treatment are needed to avoid serious complications.

Early detection of osteoarthritis in rabbits using MRI with a double-contrast agent.

BACKGROUND: Articular cartilage degeneration has been evaluated by magnetic resonance imaging (MRI). However, this method has several problems, including its time-consuming nature and the requirement of a high magnetic field or specialized hardware. The purpose of this study was to sequentially assess early degenerative changes in rabbit knee articular cartilage using MRI with a new double-contrast agent. METHODS: We induced osteoarthritis (OA) in the right knee of rabbits by anterior cruciate ligament transection and partial medial meniscectomy. Proton density-weighted images and T2-calculated images were obtained before and after contrast agent injection into the knee. The signal intensity ratio (SIR) values on the proton density-weighted images were calculated by dividing the signal intensity of the articular cartilage by that of joint fluid. Six rabbits were examined using MRI at 2 (designated 2-w OA) and 4 weeks (4-w OA) after the operation. Histological examination was performed 4 weeks after the operation. One rabbit was histologically examined 2 weeks after the operation. The control consisted of six rabbits that were not subjected to the operation. The SIR values, T2 values and the thicknesses of the cartilage of the 2-w OA, 4-w OA and the control before and after contrast agent injection were analyzed. The Mankin score and OARSI (Osteoarthritis Research Society International) score were used for the histological evaluation. RESULTS: Significant differences in the SIR and T2 values of the medial and lateral condyles of the femur were found between the control and the 4-w OA only after contrast agent injection. No significant differences were found in the SIR and T2 values before contrast agent injection between the control, the 2-w OA and 4-w OA. The thickness of the articular cartilage revealed no significant differences. In the histological assessment, the Mankin score and OARSI score sequentially increased from the control to the 4-w OA. CONCLUSION: We evaluated the SIR and T2 values of the knees in a rabbit OA model and a control model using a new double-contrast agent. MRI with this agent enabled OA detection earlier than using conventional MRI.

Therapeutic outcomes of muscular advancement by an arthroscopic-assisted modified Debeyre-Patte procedure for irreparable large and massive rotator cuff tears.

BACKGROUND: In cases of the large or massive rotator cuff tears, retear rates after rotator cuff repairs remain high. We introduced an arthroscopic-assisted modified Debeyre-Patte procedure which enables to decrease the tension of torn rotator cuff by sliding supraspinatus and infraspinatus laterally keeping fascia connection to the rhomboids. PURPOSE: The objective of this study was to examine the clinical outcomes and retear rates after an arthroscopic-assisted modified Debeyre-Patte procedure for irreparable large and massive rotator cuff tears. METHODS: Thirty-three rotator cuff tear patients (34 shoulders) were selected. These patients underwent arthroscopic-assisted modified Debeyre-Patte procedures and were observed postoperatively for at least 24 months. Magnetic resonance imaging (MRI) was used to evaluate the preoperative location of the torn rotator cuff stump and fatty infiltration of the muscles composing the rotator cuff, as well as the repaired rotator cuffs. Shoulder functional evaluations through the use of the Constant and Murley scores and the University of California Los Angeles (UCLA) shoulder score were compared before and after surgery, and the preoperative global fatty degeneration index (GFDI) was compared between retear and healed shoulders. RESULTS: MRI showed that 77% of shoulders were healed and 23% exhibited retear postoperatively. The mean preoperative GFDI was 1.99 among the 26 healed shoulders and 2.54 among the 8 retear shoulders (p < .05). When the Goutallier's classification was grade 3 or lower for all 3 cuff muscles for fatty infiltration, the retear rate was 14.3%. The mean Constant and Murley scores in healed and retear groups respectively improved from 34.7 ± 15.8, 30.0 ± 15.1 points (p = 0.47) preoperatively to 70.8 ± 8.3, 53.9 ± 14.0 points (p < .001), and UCLA scores in healed and retear groups from 13.8 ± 3.9, 12.4 ± 5.0 points (p = 0.46) preoperatively to 32.8 ± 2.7, 28.4 ± 3.6 points (p < .001). CONCLUSION: The clinical outcomes of healed shoulders after the arthroscopic-assisted modified Debeyre-Patte procedure were favorable. If the torn rotator cuff stump is retracted near the glenoid fossa, and the rotator cuff muscle scored Goutallier grade 3 or lower, this modified Debeyre-Patte procedure would be a viable option.

Validity of radial magnetic resonance imaging to determine the extent of Bankart lesions.

PURPOSE: The objectives were to compare conventional oblique coronal and axial images with radial images to determine the capacities of these modalities for visualizing sites in the glenoid labrum. MATERIALS AND METHODS: The glenoid labra of 45 patients without a labrum injury and 30 patients with Bankart lesions were examined by magnetic resonance imaging using three different sections. RESULTS: The radial images permitted a greater range of assessment of the morphology of the glenoid labrum than the conventional images. CONCLUSION: Radial magnetic resonance imaging is a useful method for evaluation of the glenoid labrum and enables wider visualization than conventional methods.

Effect of Footprint Preparation on Tendon-to-Bone Healing: A Histologic and Biomechanical Study in a Rat Rotator Cuff Repair Model.

PURPOSE: To compare the histologic and biomechanical effects of 3 different footprint preparations for repair of tendon-to-bone insertions and to assess the behavior of bone marrow-derived cells in each method of insertion repair. METHODS: We randomized 81 male Sprague-Dawley rats and green fluorescent protein-bone marrow chimeric rats into 3 groups. In group A, we performed rotator cuff repair after separating the supraspinatus tendon from the greater tuberosity and removing the residual tendon tissue. In group B, we also drilled 3 holes into the footprint. The native fibrocartilage was preserved in groups A and B. In group C, we excavated the footprint until the cancellous bone was exposed. Histologic repair of the tendon-to-bone insertion, behavior of the bone marrow-derived cells, and ultimate force to failure were examined postoperatively. RESULTS: The areas of metachromasia in groups A, B, and C were 0.033 ± 0.019, 0.089 ± 0.022, and 0.002 ± 0.001 mm2/mm2, respectively, at 4 weeks and 0.029 ± 0.022, 0.090 ± 0.039, and 0.003 ± 0.001 mm2/mm2, respectively, at 8 weeks. At 4 and 8 weeks postoperatively, significantly higher cartilage matrix production was observed in group B than in group C (4 weeks, P = .002; 8 weeks, P < .001). In green fluorescent protein-bone marrow chimeric rats in group B, bone marrow-derived chondrogenic cells infiltrated the fibrocartilage layer. Ultimate force to failure was significantly higher in group B (19.7 ± 3.4 N) than in group C (16.7 ± 2.0 N) at 8 weeks (P = .031). CONCLUSIONS: Drilling into the footprint and preserving the fibrocartilage improved the quality of repair tissue and biomechanical strength at the tendon-to-bone insertion after rotator cuff repair in an animal model. CLINICAL RELEVANCE: Drilling into the footprint and preserving the fibrocartilage can enhance repair of tendon-to-bone insertions. This method may be clinically useful in rotator cuff repair.

Stimulation of Rotator Cuff Repair by Sustained Release of Bone Morphogenetic Protein-7 Using a Gelatin Hydrogel Sheet.

Bone morphogenetic protein-7 (BMP-7) promotes not only osteogenesis but also matrix production in chondrocytes and tenocytes. However, because of its short half-life, maintaining local concentrations of BMP-7 is difficult. We examined the use of a gelatin hydrogel sheet (GHS) for the sustained release of BMP-7 in stimulating rotator cuff repair at the tendon-to-bone insertion. Twelve-week-old male Sprague-Dawley rats were used. Radiolabeled BMP-7 ((125)I-BMP-7) was injected into the subacromial bursa in the (125)I-BMP-7 group, whereas a GHS impregnated with (125)I-BMP-7 was implanted on the tendon attached to the tendon-to-bone insertion in the (125)I-BMP-7+GHS group. Levels of (125)I-BMP-7 in the tendon-to-bone insertion were assessed at 1, 3, 7, 14, and 21 postoperative days. The BMP-7 concentrations were significantly higher in the (125)I-BMP-7+GHS group than in the (125)I-BMP-7 group. Next, the bilateral supraspinatus tendons were resected and sutured to the greater tuberosity of the humerus using the Mason-Allen technique. Treatment groups were created as follows: either phosphate-buffered saline (PBS) or BMP-7 was injected into the subacromial bursa in the PBS and BMP-7 groups, whereas a GHS impregnated with either PBS or BMP-7 was implanted on the repaired tendon attached to the tendon-to-bone insertion in the PBS+GHS and BMP-7+GHS groups. The resected specimens were stained at 2, 4, and 8 postoperative weeks with hematoxylin and eosin as well as Safranin O, and tissue repair was evaluated histologically by using the tendon-to-bone maturing score. Tissue repair was assessed biomechanically at 4 and 8 postoperative weeks. The BMP-7+GHS group at 8 postoperative weeks demonstrated a favorable cartilage matrix production and tendon orientation; moreover, the tendon-to-bone maturing score and the ultimate force-to-failure were the highest in this group. The ability of GHS to provide controlled release of various growth factors has been previously reported. We confirmed that the GHS releases BMP-7 in a sustained manner in the rat shoulder joint. At 8 postoperative weeks, the repaired tissue was mostly restored, both histologically and biomechanically, in the BMP-7+GHS group. We therefore conclude that the sustained release of BMP-7 from a GHS can stimulate rotator cuff repair.