Technical Considerations for an Anteromedializing Tibial Tubercle Osteotomy

Background: Tibial tubercle osteotomy and distal realignment allows for adjustment to the patellofemoral articulation in order to improve patellar tracking and redistribute patellar contract pressures. Indications: A healthy, active 39-year-old woman status post right knee tibial tubercle osteotomy presented with >2 years of patellar instability symptoms in the left knee. Imaging revealed a tibial tubercle to trochlear groove (TT-TG) distance of 21 mm and patellar tendon lateral trochlear ridge (PT-LTR) distance of 14 mm. Technique Description: After knee arthroscopy is performed, an open incision is made along the inferomedial patellar tendon. Two pilot holes are created before a sagittal saw is used to make the tibial tubercle osteotomy, before completing it with an osteotome. Anteromedialization and/or distalization of the osteotomy is performed relative to templated values in order to improve patellar articulation. After correction, 3 bicortical screws are placed to achieve stable fixation. Results: There were no immediate complications following surgery. Surgical management led to improvement of the patient’s patellofemoral pain, which allowed return to prior baseline level of function. Discussion/Conclusion: The preferred technique for an anteromedialzing tibial tubercle osteotomy is presented. An anteromedializing tibial tubercle osteotomy is an effective surgical option for patients with evidence of patellar maltracking or central or lateral patellar chondromalacia whom have failed conservative management. This case demonstrates the efficacy of an anteromedializing tibial tubercle osteotomy to provide pain relief by improving patellar tracking and offloading patellar contact pressures on areas of prominent chondral wear.

Bone mineral density changes in a free vascularised fibular graft in the distal femoral bone after osteosarcoma in a 10-year-old boy: a 7-year follow-up

A 10-year-old boy presented with continuous reports of pain located to the left knee. Imaging revealed a sclerotic process in the left distal femur, and biopsies were consistent with chondroblastic osteosarcoma. As part of standard treatment the patient underwent neoadjuvant chemotherapy followed by limb sparring surgery and adjuvant chemotherapy. The entire tumour was excised and femoral bone reconstruction was performed with a double barrel free vascularised fibular graft. Bone mineral density (BMD) can be decreased in childhood survivors of cancer. The patient was followed for 7 years with dual-energy X-ray absorptiometry scans in order to assess BMD and graft adaption. Despite two accidental fractures to the graft region local and global BMD underwent an overall increase. Approximately 7 years after tumour resection the patient had a global Z-score of 0.2, which is considered within normal range.

Design and verification of 5-channel 1.5T knee joint receiving coil based on wearable technology

BACKGROUND: Over the past 20 years, magnetic resonance receiving coil technology has developed rapidly. The traditional, commercial knee joint coil has a fixed mechanical structure. To meet the imaging needs of most patients, it is necessary to ensure that the mechanical geometry of the coil is as large as possible. Therefore, different quality images can be obtained by filling coefficients under loads of knees of different sizes. Lufkin et al. [1] have demonstrated that the signal-to-noise ratio (SNR) of coil imaging is directly proportional to its filling coefficient, which is S/N≈QL*η. Thus, the pursuit of an optimal coil filling coefficient is an important way to improve the coil imaging quality. OBJECTIVE: This study combines wearable concepts and coil development techniques and applies flexible and elastic materials to coil designs. METHODS: We used an elastic material instead of the traditional fixed mechanical structure to develop a 1.5T 5-channel knee joint receiving coil that can be attached to knee joints of different sizes within a certain range, allowing the coil to achieve a maximum filling coefficient under the loads of knees of different sizes. RESULTS: Compared to commercial 8-channel knee coils, the phantom test and clinical knee joint imaging demonstrated that the SNR of the developed coil increased by four times in the shallow layer and two times in the deep layer, under different load conditions. CONCLUSION: This high SNR performance demonstrates potential for the realization of high resolution and fast imaging sequences in knee imaging.

Knee Imaging Following Anterior Cruciate Ligament Reconstruction: The Surgeon's and Radiologist's Perspectives

Anterior cruciate ligament (ACL) tears are common injuries that if left untreated can result in chronic instability, cartilage damage, meniscal tears, and ligamentous injuries, eventually leading to early osteoarthritis. ACL reconstruction surgeries are therefore increasingly being performed. Despite the fact that most patients achieve excellent postoperative results, patients can present with recurrent instability and pain. These patients often undergo imaging with radiographs, magnetic resonance imaging, and/or computed tomography. An understanding of the imaging appearance of the normal ACL reconstruction and common causes of failure is therefore essential for the interpreting radiologist. This article reviews surgical techniques for ACL reconstruction, highlighting recent technical advances, the normal imaging appearance after ACL reconstruction, etiologies for reconstruction failure, and the diagnosis of these with the aid of imaging.