Peroxisome proliferator–activated receptor (PPAR) subfamily play an important role in chondrogenesis. Previous study has reported that mixture of GW0742 (PPAR-δ agonist), hyaluronic acid (HA) and mesenchymal stem cells (MSCs) enhance chondrogenesis. The purpose of this study is to compare with efficacies of commercially available HA and demonstrate correlation of PPAR-γ and PPAR-δ. In this experimental study, MSCs were cultured with chondrogenic media and clinical HA gels (Euflexxa®, Synvisc®, Orthovisc® and Supartz®) using micormass culture method. Expression of type Ⅰ, Ⅱ collagen and matrix metalloprotease-13 (MMP-13) was measured by immunoblotting. MSCs were cultured with chondrogenic media and/or HA and/or GW0742 and/or rosiglitazone (PPAR-γ agonist) and/or human osteoarthritis synovial fluid. Immunoblotting was used to measure expression of type Ⅱ collagen and PPAR-γ. To identify the effective dose for chondrogenesis and adipogenesis, either 0.1, 1, 5 or 10 μM of rosiglitazone was added to MSCs in chondrogenic media or adipogenic media. Clinical HA gels inhibited expression of type Ⅰ collagen and enhanced the expression of MMP-13. Type Ⅱ collagen expression was significantly elevated in all treatment groups except Supartz®. GW0742 decreased the expression of PPAR-γ with/without inflammation condition. Rosiglitazone enhanced adipogenesis in a dose-dependent manner and enhanced the expression of type Ⅱ collagen under inflammation condition. Otherwise, the expression of type Ⅱ collagen and formation of chondrocyte spheroids showed a dose-dependent manner with a peak at 1 μM of rosiglitazone. PPAR-γ has a considerable anti-inflammatory effect and a strong pro-adipogenic effect, which inhibits the chondrogenic effect. PPAR-γ is related with PPAR-δ and shows a chondrogenic effect at lower concentrations. And clinical HA gels shows various efficacy of chondrogenesis. This study suggested that PPAR-γ and PPAR-δ are key regulatory factors of chondrogenesis.

Osteoarthritis (OA) is a chronic degenerative joint disease accompanied by an inflammatory milieu that results in painful joints. The pathogenesis of OA is multifactorial, with genetic predisposition, environmental factors, and traumatic injury resulting in the direct or indirect loss of cartilage. The articular cartilage can also be damaged by direct focal traumatic injury. Articular cartilage provides a smooth, deformable bearing surface with a low coefficient of friction, increased contact area, and reduced contact stress. Articular type II hyaline cartilage lines the synovial joints and, when injured, has a limited ability for repair, except for the most superficial layers via diffusion from the synovial fluid, secondary to no blood supply, a complex structure, and a low metabolic rate. Restoring the articular surface can relieve pain and restore function. Although many strategies have been developed to regenerate type II collagen based on the extent of the lesion, surgical treatments are still evolving. The peroxisome proliferator-activated receptor delta (PPARδ) agonist and collagen treatment of mesenchymal stem cells (MSCs) enhance the chondrogenic capacity in vitro. We present a novel technique for cartilage restoration in a rabbit cartilage osteochondral defect model using a PPARδ agonist (GW0742)-infused 3D collagen scaffold to induce type II cartilage from MSCs.

The double squeeze technique for fracture stabilization is a technique in which the surgeon uses a second reduction clamp to hold and stabilize a smaller reduction clamp that reduces a fracture or plate yet is too small to hold by itself. This technique greatly assists anatomic fracture reduction and stabilization and allows the surgeon to complete the operation when there is limited reduction instrumentation available, or the surgeon needs more excursion on a small clamp holding a fracture and does not want to change instruments and possibly lose a reduction. We present a case of the double squeeze clamp technique, which to our knowledge has not been reported, to facilitate limited open reduction percutaneous plate stabilization in a distal tibia fracture. This case report presents an 18-year-old male with a closed, oblique, displaced right distal tibia fracture following a crush injury to the extremity with a tree while using a chainsaw. He was initially seen in the emergency room and was discharged home in a splint to follow-up with the orthopedic surgeon on call. The family requested follow-up with our practice 3 days later and requested surgery at their rural local hospital secondary to insurance reasons. Patient requested plate fixation to treat his fracture. Due to limited reduction instrumentation in the facility, a double squeeze reduction clamp technique using a pointed reduction clamp on a serrated reduction clamp that was too small to hold the plate on the reduced fracture accomplished stabilization of the plate on the fracture while screws were placed. The double squeeze reduction clamp technique using one reduction clamp on a smaller reduction clamp greatly increases the ability to successfully reduce and stabilize multiple variations of different fractures whether secondary to differences in sizes of the bones, different types of bones, or in our case limited fracture reduction tools available.

Introduction: Osteochondromas are the most common benign tumors of the bone and can be sessile or pedunculated. Although osteochondromas are typically seen in the long bones, they are rarely seen in the small bones of the hand or foot. Verruca vulgaris, also known as the common wart, is one of the most common skin conditions presenting to physicians and must be distinguished either clinically or histologically from other hyperkeratotic conditions, including bone conditions such as bone tumors that can place pressure on the skin and cause callus formation that can mimic a wart or create skin deformity. A high index of suspicion for underlying bone mass or tumor should be entertained when evaluating patients for skin conditions, particularly of the hand or foot, with failure to improve with treatment. Case Report: This case report presents a 20-year-old male with a pedunculated osteochondroma of the left fourth distal phalanx with hyperkeratotic skin overlying the mass at the end of the toe. He was initially treated by a family doctor and podiatrist for verruca vulgaris for over 5 years with two treatments of liquid nitrogen cryotherapy and surgical excision of the mass when the treating podiatrist encountered bone and recommended radiographs. The family requested follow-up with our practice several days later after they were told the patient had a bone tumor. The patient requested surgical excision of the osteochondroma secondary to pain with activities and difficulties with his vocation as a pilot. Conclusion: All physicians must be mindful of an underlying bone tumor or mass in patients presenting with skin changes, particularly about the foot or hand. Knowledge that an underlying bone tumor can present as a verruca vulgaris may prevent a delay in diagnosis or unnecessary treatment when evaluating and treating a patient with a skin lesion. Fortunately, our case was a benign osteochondroma; a malignant tumor with a delay in diagnosis could lead to loss of limb or life. Keywords: Osteochondroma, verruca vulgaris, skin changes, exostosis, bone tumor, wart.

Idiopathic necrotizing granuloma localized to a native knee joint is an exceedingly rare entity. While non-necrotizing granulomas as defined by organized epithelioid histiocytes and multinucleated giant cells without central necrosis are more commonly associated with autoimmune, foreign body, or inflammatory conditions, the presence of necrosis raises concern for more aggressive pathology, particularly infectious etiologies such as mycobacterial or fungal disease. Accordingly, idiopathic necrotizing granuloma remains a diagnosis of exclusion, requiring systematic evaluation to rule out infectious, post-procedural, autoimmune, and systemic granulomatous causes. This case report presents a 54-year-old man with a necrotizing granuloma within the suprapatellar pouch of the right knee noted at the time of arthroscopy for a medial meniscal tear and osteoarthritis. The patient did complain of pain directly in the area corresponding to the mass, the peripatellar region, as well as the medial joint line. He was initially treated with conservative measures including acetaminophen, non-steroidal anti-inflammatory, methylprednisolone, a knee sleeve, and physical therapy. After failure to improve, the patient requested to follow up with our practice due to increasing pain and difficulty with ambulation for surgical consideration. Radiographs and MRI revealed joint space narrowing consistent with osteoarthritis and a medial meniscal tear without mention of a mass. The patient requested surgical treatment secondary to pain with activities and difficulties with his vocation as a laborer. All physicians must be mindful that necrotizing granulomas indicate more aggressive tissue injury and should raise immediate concern for infection or other aggressive pathology mandating a comprehensive diagnostic evaluation to rule out systemic conditions and to prevent a delay in diagnosis or treatment. Knowledge that necrotizing granuloma can present as a painful mass within the knee without prior surgery, prior injection, infection, or systemic disease to our knowledge has not been described.