Can convertible metal-backed glenoid components replace cemented polyethylene glenoid components in anatomical total shoulder arthroplasty?

BACKGROUND: Anatomical total shoulder arthroplasty (aTSA) has been used to manage degenerative diseases such as primary osteoarthritis. An increase in the use of this procedure has led to several developments in humeral and glenoid components to improve patient outcomes. This study aimed to compare clinical and radiological outcomes of the newly-introduced convertible metal-backed glenoid components with cemented polyethylene glenoid components in aTSA, and to determine whether the new component would be comparable to a conventional one for reducing the burden of future revision or conversion surgeries. METHODS: Medical records of fifty patients who underwent aTSA with at least two years of follow-up were retrospectively reviewed. Eighteen patients received convertible metal-backed glenoid components with vitamin E1-coated liner (MB group), while thirty-two patients received conventional cemented polyethylene glenoid components (PE group). Pre- and postoperative clinical and radiological outcomes (acromion-greater tuberosity angle [AGA] and humeral lateral offset [LO]) at final follow-up were assessed. Radiolucent lines (RLLs) and loosening around the humeral and glenoid components were also evaluated. RESULTS: Clinical outcomes improved after surgery in both groups (all p < 0.001). The arc of rotation measured by AGA improved postoperatively in both groups (all p < 0.001), and AGA and LO were not different according to the type of glenoid components (all p > 0.05). Overall complication rates including RLLs of PE and MB groups were 43.8% (14/32) and 16.7% (3/18), respectively (p = 0.031). Although the PE group had more RLLs than did the MB group (p < 0.05), related symptoms and/or glenoid implant loosening were not observed in both groups. Subscapularis failure occurred in two patients in the PE group and in one in the MB group. CONCLUSION: The convertible metal-backed glenoid implant with vitamin E1-coated liner may be a good alternative for considering the potential for an easier conversion to reverse total shoulder arthroplasty.

WITHDRAWN: Ameloblast-like characteristics of human Hertwig's epithelial rest of Malassez/epithelial rest of Malassez cells via interaction with stem cells from human exfoliated deciduous teeth.

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Angiogenic Capacity of Dental Pulp Stem Cell Regulated by SDF-1α-CXCR4 Axis.

Previously, the perivascular characteristics of dental pulp stem cells (DPSCs) were reported, which suggested the potential application of DPSCs as perivascular cell source. In this study, we investigated whether DPSCs had angiogenic capacity by coinjection with human umbilical vein endothelial cells (HUVECs) in vivo; in addition, we determined the role of stromal cell-derived factor 1-α (SDF-1α) and C-X-C chemokine receptor type 4 (CXCR4) axis in the mutual interaction between DPSCs and HUVECs. Primarily isolated DPSCs showed mesenchymal stem cell- (MSC-) like characteristics. Moreover, DPSCs expressed perivascular markers such as NG2, α-smooth muscle actin (α-SMA), platelet-derived growth factor receptor ß (PDGFRß), and CD146. In vivo angiogenic capacity of DPSCs was demonstrated by in vivo Matrigel plug assay. We could observe microvessel-like structures in the coinjection of DPSCs and HUVECs at 7 days postinjection. To block SDF-1α and CXCR4 axis between DPSCs and HUVECs, AMD3100, a CXCR4 antagonist, was added into Matrigel plug. No significant microvessel-like structures were observed at 7 days postinjection. In conclusion, DPSCs have perivascular characteristics that contribute to in vivo angiogenesis. The findings of this study have potential applications in neovascularization of engineered tissues and vascular diseases.

Anterior odontoid fixation using a 4.5-mm Herbert screw: The first report of 20 consecutive cases with odontoid fracture.

BACKGROUND: Anterior screw fixation provides the best anatomical and functional results for odontoid process fracture (type II and "shallow" type III) with intact transverse ligament. The purpose of this study is to evaluate the clinical results of the 4.5-mm-diameter cannulated Herbert screw in the anterior odontoid fixation. METHODS: From May 2003 to November 2005, 20 consecutive cases of types II and III odontoid process fractures were treated with anterior screw fixation using a 4.5-mm Herbert screw. The Herbert screw has double threads, with different pitches on the distal and proximal ends. It has no head, so it can be inserted through articular cartilage and buried below bone surface. RESULTS: There were 16 male and 4 female patients whose ages ranged from 15 to 76 years (mean, 43.7 years). The fracture type was type II-A in 4 patients, II-N in 9 patients, II-P in 5 patients, and III in 2 patients. The range of follow-up was 3 to 36 months (mean, 18.6 months). There were an overall bone fusion rate in 17 cases (85%), fibrous union in 1 (5%), and nonunion in 2 (10%). Overall, complication unrelated to hardware occurred in the one (postoperative dysphagia) without complication-related hardware failure. CONCLUSIONS: The Herbert screw is very useful in anterior fixation for types II and III odontoid process fractures. This series showed successful clinical results comparable with that of the 3.5-mm cannulated cancellous screw and distinct advantages over conventional screws in the aspect of biomechanical properties and less invasiveness.

A case of cavernous sinus thrombophlebitis and meningitis as a complication in osteopetrosis.

Osteopetrosis is a rare genetic bone disease characterized by increased bone density but prone to breakage due to defective osteoclastic function. Among two primary types of autosomal dominant osteopetrosis (ADO), osteopetrosis type II is characterized by sclerosis of bones, predominantly involving the spine, the pelvis, and the skull base. Fragility of bones and dental abscess are leading complications. This report presents a case of osteopetrosis in a 52-years-old female, which was complicated by the development of cavernous sinus thrombophlebitis and meningitis. She was suffered from multiple fractures since one year ago. Laboratory data revealed elevated serum levels of tartrate resistant acid phosphatase (TRAP) without carbonic anhydrase II DNA mutation. A thoracolumbar spine X-ray showed, typical findings of ADO type II (ADO II; Albers-Schönberg disease), prominent vertebral endplates so called the 'rugger jersey spine'. Her older sister also showed same typical spine appearance. We report a case of ADO II with cavernous sinus thrombophlebitis and meningitis that was successfully treated with long-term antibiotics with right sphenoidotomy.

Modified C1 lateral mass screw insertion using a high entry point to avoid postoperative occipital neuralgia.

For the past decade, a screw-rod construct has been used commonly to stabilize the atlantoaxial joint, but the insertion of the screw through the C1 lateral mass (LM) can cause several complications. We evaluated whether using a higher screw entry point for C1 lateral mass (LM) fixation than in the standard procedure could prevent screw-induced occipital neuralgia. We enrolled 12 consecutive patients who underwent bilateral C1 LM fixation, with the modified screw insertion point at the junction of the C1 posterior arch and the midpoint of the posterior inferior portion of the C1 LM. We measured postoperative clinical and radiological parameters and recorded intraoperative complications, postoperative neurological deficits and the occurrence of occipital neuralgia. Postoperative plain radiographs were used to check for malpositioning of the screw or failure of the construct. Four patients underwent atlantoaxial stabilization for a transverse ligament injury or a C1 or C2 fracture, six patients for os odontoideum, and two patients for C2 metastasis. No patient experienced vertebral artery injury or cerebrospinal fluid leak, and all had minimal blood loss. No patient suffered significant occipital neuralgia, although one patient developed mild, transient unilateral neuralgia. There was also no radiographic evidence of construct failure. Twenty screws were positioned correctly through the intended entry points, but three screws were placed inferiorly (that is, below the arch), and one screw was inserted too medially. When performing C1-C2 fixation using the standard (Harms) construct, surgeons should be aware of the possible development of occipital neuralgia. A higher entry point may prevent this complication; therefore, we recommend that the screw should be inserted into the arch of C1 if it can be accommodated.

Posterior C1-2 fusion using a polyaxial screw/rod system for os odontoideum with bilateral persistence of the first intersegmental artery.

The authors report the case of a patient with os odontoideum, myelopathy secondary to atlantoaxial instability, and bilaterally persistent first intersegmental artery at the craniovertebral junction. Instead of occipitocervical fusion, C1-2 posterior fusion was performed using a polyaxial screw/rod system. The information obtained from 3D CT angiography studies may highlight the potential risk of vertebral artery injury in advance and reduce the risk of an intraoperative vertebral artery injury. In addition, C-1 lateral mass screw placement may be a safe procedure for cases of atlantoaxial subluxation in which there are persistent C-1 intersegmental arteries.

Cement augmented anterior reconstruction with short posterior instrumentation: a less invasive surgical option for Kummell's disease with cord compression.

We report the surgical procedure and clinical outcomes of a cement augmented anterior reconstruction with pedicle screw fixation for osteoporotic vertebral collapse with an intravertebral cleft (Kummell's disease). Ten consecutive patients with cord compression were enrolled in this study. The mean number of fused segments was 3.2. Instrumentation and posterolateral bone grafts were performed for one level above and below the collapsed vertebra with the exception of one patient. Polymethylmethacrylate (PMMA) cement was then injected into the intravertebral cleft and posterior decompression was performed when needed. The visual analog scale (VAS) pain score and Frankel grade were used to evaluate the clinical results and radiological parameters were also assessed. The mean VAS score before vertebroplasty was 7.5, which was reduced to 3.2 postoperatively, and was 3.7 at the most recent follow-up. The mean follow-up duration was 12.1 months. Seven (83%) of the eight patients with motor deficits showed an improvement in neurological function by at least 1 Frankel grade. The mean decrease in the kyphosis (Cobb) angle was 12.6° and the wedge angle was 12.1° (p<0.05). However, the angle improvement regressed slightly during follow-up. None of the patients showed vertebral collapse, or loss or leakage of PMMA into the canal. One patient developed wound dehiscence. There was no need for revision or evidence of instrument failure. Based on the preliminary results, we advocate the use of short instrumentation in combination with vertebroplasty with PMMA and posterolateral fusion for Kummell's disease in patients who are elderly or medically compromised.