Finite element analysis of the knee joint: a computational tool to analyze the combined behavior after treatment of torn ligaments and menisci in the human knee joint.

Finite element analysis (FEA) is a fundamental tool that can be used in the orthopaedic world to simulate and analyze the behaviour of different surgical procedures. It is important to be aware that removing more than 20% of the meniscus could increase the shear stress in the cartilage and enlarge the risk of knee joint degeneration. In this fact, the maximal shear stress value in the medial cartilage increased up to 225% from 0.15 MPa to 0.5 MPa after medial meniscectomy. Also, meniscal root repair can improve meniscal biomechanics and potentially reduce the risk of osteoarthritis, even in cases of a loose repair. FEA has been used to better understand the biomechanical role of cruciate ligaments in the knee joint. ACLr with bone-patellar tendon-bone graft at 60 N of pretension and double-bundle PCLr were closer to that of a native knee in terms of biomechanics. The addition of a lateral extra-articular augmentation technique can reduce 50% of tibial translation and internal rotation, protecting the graft and minimizing the risk of re-rupture. Interestingly, anatomic and non-anatomic medial patellofemoral ligament reconstruction increased the pressure applied to the patellofemoral joint by increasing patellar contact pressure to 0.14 MPa at 30° of knee flexion using the semitendinosus as a graft. After all the advances in medical imaging technologies, future studies should take into consideration patient-specific data on both anatomy and mechanics, in order to better personalize the experimental model.

Osteopoikilosis in a patient with familial adenopolyposis : A case report.

Osteopoikilosis, a sclerosing bone dysplasia, is an asymptomatic incidental finding characterised by multiple bone islands. Although it requires no treatment there can be diagnostic uncertainty as appearances can be similar to osteoblastic metastases or metabolic disorders such as Paget disease. We present a case of osteopoikilosis in a patient with familial adenopolyposis and discuss the clinical presentation, image findings and key considerations in diagnosis of this benign entity.

Subchondral insufficiency fracture of the medial femoral condyle treated conservatively with early non-weightbearing.

Spontaneous osteonecrosis of the knee (SONK) is a poorly understood but debilitating disease, that is a common cause of unilateral acute knee pain and swelling. The term "SONK" has been replaced by the term "subchondral insufficiency fracture" in the latest pathology and imaging literature. Few studies investigated the pathogenesis of SONK by examining the histological changes of the tissues. Very recently, the development of SONK was associated with a meniscal root tear. In terms of the preferred imaging, plain radiographs can confirm the diagnosis in late stages; however, magnetic resonance imaging (MRI) scan is often required. Regarding the treatment, conservative management is usually the treatment of choice in early stages, including a period of non-weightbearing or the use of medications, such as nonsteroidal anti-inflammatory drug (NSAIDS) or bisphosphonates. However, when SONK progresses, often a surgical intervention is required, such as knee replacement, but also minimally invasive techniques, such as arthroscopic intervention, have been described. We present a case of early SONK and discuss the possible pathogenesis of SONK, the clinical presentation, the radiological findings, and we focus on the importance of early diagnosis and early off-load period that is required to prevent further progression of the disease.

Lipoma arborescens with patellofemoral osteoarthritis and genu valgum.

Lipoma arborescens is a rare benign intra articular lesion characterized by lipomatous proliferation of the synovium. The condition typically affects the knee presenting with atraumatic pain and swelling. It should be considered in the differential diagnosis of monoarthritis and joint effusion. Diagnosis is made on MRI with characteristic features. We present a rare case of lipoma arborescens with patellofemoral osteoarthritis and genu valgum. We discuss the clinical presentation, radiological findings, and management.

Gluteus medius calcific tendonitis as a cause of severe anterior hip pain.

Calcific tendinopathy in the gluteus medius is uncommon and sporadically reported. It may be asymptomatic or present with acute or chronic pain. Pain is usually isolated to the lateral hip overlying the gluteal muscles or greater trochanter. We present a rare case of gluteus medius calcific tendonitis as a cause of severe anterior hip pain. Given the atypical local and clinical presentation these can be often misdiagnosed as septic arthritis or fracture which may lead to overtreatment and even unnecessary surgery. This article will detail the clinical presentation, imaging findings, and clinical course following treatment. This will facilitate the clinician in making a timely diagnosis and establishing an effective treatment course.

Does stem profile have an impact on the failure patterns in revision total knee arthroplasty?

INTRODUCTION: Revision total knee arthroplasty (RTKA) has been increasing continuously. The results of RTKA still remain unsatisfactory. Failure patterns and risk factors in RTKA were thoroughly analyzed, with periprosthetic joint infections (PJI) and aseptic loosening remaining at the forefront of re-revision (ReRTKA) causes. While there is evidence that stem profile impacts the revisability of cemented implants, its association with the modes of RTKA failure is unknown. METHODS: 50 consecutive ReRTKA performed in a single orthopedic center during 2016-2017 were retrospectively analyzed. The cases were stratified according to age, sex, number of preexisting revisions, fixation technique, stem design and causes of re-revision. All explanted implants with conical vs. cylindrical stem profiles were compared. RESULTS: Mean age was 67 ± 11.5, and 54% were females. 72% of the cases had ≥ 3 previous revisions. 88% were full-cemented, 3% hybrid and 9% press-fit stems. 36% of the RTKA had conical, 58% cylindrical and 6% combined stem profiles. 92% of the RTKA components were removed. Removal causes were: PJI (52.2%), aseptic loosening (34.8%), implant malposition (9.8%), painful knee (1.1%) and instability (2.2%). While the overall RTKA failure patterns were equally distributed between conical and cylindrical stems, subgroup analysis of only cemented ReRTKA revealed a higher incidence of aseptic loosening within cylindrical stem profiles (46.7% vs. 25.7%, P = 0.05). CONCLUSION: Stem profile may have an impact on the process of aseptic loosening in cemented non-metaphyseal engaging RTKA, with cylindrical designs tending to worse outcomes than conical designs. Large cohort studies could provide more clarity on current observation.

Double Interphalangeal Joint Dislocation of the Finger in Adolescent Athletes: A Review of Two Cases and the Relevant Literature.

Double interphalangeal joint dislocation of the same finger is a rare condition. We report two cases of adolescent athletes with distal and proximal interphalangeal joint dislocation. The diagnosis was confirmed with plain radiograph, while anatomical reduction was easily obtained with gentle longitudinal traction. A simple immobilization of the injured finger was applied by buddy taping for two weeks. Early mobilization as tolerated was recommended, and they have made a full return to their previous status of activities within 5 months. We also provide a review of the literature detailing demographic characteristics, cause and mechanism of injury with associated injuries, treatment options, and functional outcomes in this population.

Tibia vara or Blount's disease: Why an early diagnosis and treatment are important?

Tibia vara is an asymmetrical disorder of the proximal tibia that produces a threedimensional deformity, which was first described by Blount in 1937. A 6-year-old boy presented with a history of anterior knee pain with progressive bowing of his right leg over the last 1 year after having a fall while playing soccer. An early diagnosis and treatment of this disease can have a great functional impact and lead to very good health outcomes.

Rehabilitation exercise program after surgical treatment of quadriceps tendon rupture: A case report.

OBJECTIVES: This case report describes in detail the rehabilitation exercise program, provide post-operative therapeutic objectives/recommendations and to facilitate the return to a possible schedule of ADL and participation in sports after the surgical treatment of quadriceps tendon rupture. Also, the exact surgical technique is described. DESIGN: A single case report. PARTICIPANT: The patient was an active 53-year-old man who sustained this injury as a result of a sudden misstep with his left foot into a hole, while he was trekking across muddy countryside. Clinical examination of the knee revealed skin ecchymosis, swelling and tenderness over the distal thigh. Plain radiographs showed patella baja, and the scheduled magnetic resonance imaging (MRI) showed interrupted continuity of the quadriceps tendon and the patella. A diagnosis of quadriceps tendon rupture was made and the patient was scheduled to undergo surgical intervention the following day. REHABILITATION EXERCISE PROGRAM: A well-structured rehabilitation exercise program was followed in order to ensure rapid recovery and good functional outcomes. His postoperative course progressed normally, demonstrating a return to the normal activities of daily living at 6 weeks, full active range of motion at 16 weeks, and return to sports recreational activities at 5 months. CONCLUSIONS: An early surgical treatment and subsequently a well-structured rehabilitation exercise program have contributed to maximize the functional outcomes of the patient and provide a rapid and safe return to the activities of daily living (7th week) with participation in non-contact sports after the 18th week.