Background: The posterior approach for acetabular fractures is the Kocher-Langenbeck (K-L) approach which is performed in lateral and prone positions. Lateral position is a familiar position for most orthopedic surgeons. Prone position yields multiple advantages compared to lateral position.
Methods: Between the years 2016 and 2019, 18 patients with selected acetabular fractures in which the best decision was surgical fixation using K-L approach were studied. The surgical procedure was done using K-L approach with the patient in the prone position and we used Matta scoring system to evaluate post-operative reduction quality.
Results: According to the Matta system, the anatomic reduction was observed in 13 patients (86.6%). Imperfect reduction was observed in 2 patients (13.3%), no patient had a poor reduction. Avascular necrosis (AVN) of the femoral head was seen in one patient (6.6%) and no infection and heterotopic ossification (HO) was noted.
Conclusions: The advantage of this approach in a prone position is believed to be better exposure and greater access to the quadrilateral plate (QLP) and anterior column indirectly. One of the most important advantages is that in the prone position, handling the reduction devices to indirectly reduce anterior column or QLP is much easier.

Background: Complex regional pain syndrome (CRPS) is a painful syndrome with signs such as swelling, restriction of motion, and discoloration of the skin and bone. CRPS is divided into two types based on neurological injuries. Type 1 CRPS (CRPS-I), which is more common, has no nerve damage. In this study, we used the Budapest Criteria to investigate the incidence of CRPS. We also evaluated the risk factors for the incidence of CRPS.
Methods: This single-center case series study was performed at Shariati Hospital of Tehran University of Medical Sciences, Tehran, Iran, during 2018-2019. We evaluated CRPS-I, two, and six weeks after treatment based on Budapest Criteria. The inclusion criteria included distal radius fracture confirmed by clinical and radiographic investigations. The exclusion criteria were patients with fractures in another part of the body, associated nerve damage, vascular injury, and an open fracture.
Results: Sixty-two patients with distal radius fracture who underwent casting or surgical treatment enrolled in the study. A total of 9 (14.5%) patients had CRPS-I after distal radius fracture. In 5 (8.1%) patients, CRPS-I occurred within two weeks after fracture. Also, 4 (6.5%) patients had CRPS-I after six weeks from fracture. There was no significant difference between the two sex groups in terms of CRPS (P = 0.345). This complication was significantly higher in the surgical group than in the casting group (P = 0.004).
Conclusions: Given the significant incidence of CRPS and its impact on patient's quality of life, further studies are recommended to explore solutions to reduce this complication.

Background: Acromion fractures are rare injuries that may occur because of shoulder trauma. This may be associated with distal clavicle fractures, which can be an indication for surgery. There are several methods, which are used for fixation of this type of fractures.
Case Presentation: In this paper, we presented a 34 years old man with acromion fracture in contribution to acromioclavicular (AC) joint dislocation. We applied a new method for the fixation of this fracture. The fracture was fixed by 2 screws and AC Joint was fixed by a 4-hole hook plate.
Conclusions: It is important to be aware of acromial fracture to not miss them and also for early management so that early recovery and satisfactory results can be gained.

Background: Osteoid osteoma (OO) is a benign tumor that rarely occurs in carpal bones. The occurrence of OO in trapezoid is extremely rare. We present a patient with OO of the trapezoid as 7^th reported case around the world.
Case Presentation: A 25-year-old man was referred to our clinic with a 12-month history of pain of his left wrist. He mentioned that he had wrist pain during manual activity and the pain was increasing over time. He did not have a history of trauma. He was treated with nonsteroidal anti-inflammatory drugs (NSAIDs) before being referred to our clinic; however, it did not work. Examination showed tenderness over the dorsoradial side of the left wrist. Conventional radiographs of the wrist were normal. Computed tomography (CT) demonstrated a halo radiolucent osteoid tissue surrounded by sclerotic tissue in the left trapezoid. Magnetic resonance imaging (MRI) showed a focal hypointense lesion (nidus) in the trapezoid with a 10 mm diameter. Focal increased uptake of 99mTc in his trapezoid was shown by bone scintigraphy. According to the clinical and imaging findings, we considered excisional biopsy with the diagnosis of trapezoid bone. Surgery was performed through a dorsal incision. We performed en bloc excision. Histopathological findings confirmed the diagnosis of OO. The patient got pain-free on postoperative day 3.
Conclusions: Carpal bones tumor such as OO should be considered in differential diagnosis of patients with chronic wrist pain.

Background: Osteonecrosis is the death of bone tissue due to the interruption of the blood supply. It can occur in autoimmune disease due to multiple mechanisms. It occurs rarely in some kind of multisystem disease such as Behcet’s disease (BD). The aim of this article is to present a case of BD with multifocal osteonecrosis.
Case Presentation: A 26-year-old woman with oral aphthosis, panuveitis, and retinal vasculitis was diagnosed to have BD, and oral treatment of prednisolone (0.5 mg/kg/day) together with azathioprine (2 mg/kg/day) and intravenous (IV) cyclophosphamide (CYC) (0.75 g/m²) was administered for her. Prednisolone was tapered to 15 mg/day after 3 months. Because of unresponsiveness of eye involvement to traditional immunosuppressive therapy, infliximab (5 mg/kg) was started for her, and IV CYC was discontinued. 4 months after initial therapy, she complained of her right shoulder pain. Regarding shoulder pain, magnetic resonance imaging (MRI) showed osteonecrosis of the right shoulder. After the diagnosis of osteonecrosis, prednisolone was discontinued by herself. 3 months later, she complained of both knees, both hips, and right ankle pain. According to the previous diagnosis of osteonecrosis of her right shoulder, MRI was done for all involved joints, which revealed osteonecrosis of all of them. After the diagnosis of multifocal osteonecrosis, the following tests were done that all results were normal: anticardiolipin antibody (ACA) [immunoglobulin G (IgG), immunoglobulin M (IgM)], lupus anticoagulant (LA), anti-beta-2 glycoprotein 1 (antiB2GP1) (IgG, IgM), coagulation tests, and lipid profiles.
Conclusions: Bone infarction should be considered in the differential diagnosis of patients with joint pain and without the evidence of arthritis; however, it rarely occurs in patients with BD.

Background: Old unreduced knee dislocation is rare, which means the experience is still lacking about the best treatment options. Moreover, several surgical options for this condition are still lacking in peer-reviewed research. This is a case report of the treatment of a patient who had bilateral traumatic knee dislocations that were unreduced two months after injury.
Case Presentation: A 45-year-old man with bilateral traumatic unreduced knee dislocation came 2 months after injury. He had no active knee extension and was unable to walk. He underwent open reduction and external fixation. He had a good range of motion (ROM) and painless walking in short term. After 5 years, he had acceptable ROM and painless walking, but x-rays showed persistent posterior subluxation of the left knee and some bone loss of the right tibia.
Conclusions: Open reduction, repair of torn ligaments, and external fixation was an effective treatment in regaining ROM and stability in a patient who had bilateral unreduced knee dislocations of two months duration. After five years, the patient had a satisfactory function, but radiographs showed persistent posterior subluxation of one knee and some bone loss of the tibia in the other