A Rare Case of Posterior Dislocation of Hinge Knee Prosthesis due to Wear of Anti-Luxation Device: A Case Report.

Introduction: Hinge knee joint prosthesis are utilized in a variety of surgical scenarios, including complex primary, revision, salvage surgeries, and radical resection of tumor's. Link's Endo-model Hinged Knee Prosthesis is a newer design that includes ramped tibial components for controlled pivot point motion during flexion and an anti-dislocation feature to prevent prosthesis dislocation.. The re-design of the hinge prosthesis has resulted in less force transfer along the implant bone junction. However, despite the improved design, complications can still arise. This report presents a rare complication of posterior dislocation due to polythene wear of the anti-dislocation device in a patient with a rotating hinge knee prosthesis. Case Report: After 4 years, a 42-year-old patient who had undergone multiple total knee replacements (TKRs) with a history of pain, swelling, and difficulty walking for the previous 2 months presented to us. Radiographs from the initial presentation revealed aseptic loosening, for which a revision TKR using a Link-Waldemier non-modular (rotational) joint endo-model with an anti-dislocation mechanism was performed. Three years later, the patient began experiencing episodes of instability, and a radiograph revealed posterior dislocation of the hinge knee prosthesis. As a result, a decision was made to perform revision surgery, during which the worn-out polyethylene was replaced with a new polyethylene insert, and stability was confirmed intraoperatively. Four weeks after surgery, the patient's knee range of motion was 0-120°, and all discomfort had completely subsided. At a year's follow-up, the patient's Knee Society score had improved from 40 before surgery to 90 after surgery. Conclusion: Interference in the normal framework of knee anatomy distorts its intrinsic stability. This interference can be in variable form such as bone deficiency, infection, multiple revision surgeries, and ligamentous laxity. Restoration of intrinsic stability in today's world has been made possible by a highly constraint, hinged knee prosthesis. An anti-dislocation mechanism on the rotating hinge prosthesis guards against dislocation brought on by distracted engagement. In our instance, the anti-dislocation mechanism had aseptically loosened, increasing flexion laxity and permitting severe distraction. The anti-dislocation mechanism will eventually relax, but its lifespan can be increased by proper gap balancing, which offers inherent stability and increases the anti-dislocation mechanism's stability.

A rare case of extensive neurogenic heterotopic ossification: a case report.

INTRODUCTION: Neurogenic Heterotopic ossification (NHO) is a potential sequalae and a detrimental complication following neurological insult. It is characterized by formation of localized gradually progressive, peri-articular lamellar bone formation in extra-skeletal tissues. We would like to report a rare case of heterotopic ossification involving all 4 limbs, in which we tried to restore joint mobility to improve his functional status so that he could perform his daily tasks. CASE PRESENTATION: We present a case of a 33-year-old bed ridden male, diagnosed with NHO involving all 4 limbs (bilateral hip, right knee, right shoulder, left elbow). The patient had a crippled posture, significant pain and impaired range of motion hampering movement of all four limbs which prevented him from lying down supine, sitting, walking and performing activities of daily living. After three surgeries, the patient achieved wheelchair mobilization and upright posture with the assistance of calipers. CONCLUSION: The management of NHO requires a multidisciplinary approach involving orthopaedic surgeons, neurologists & rehabilitation specialists. Prognosis of NHO depends on factors such as extent of ossification, underlying neurological condition & patients overall health.

A Rare Presentation of Bifid Tibialis Anterior Tendon in a Case of Idiopathic Congenital Talipes Equinovarus.

Introduction: Idiopathic congenital talipes equinovarus (CTEV) is one of the most extensively researched topics for decades. It has been associated with various musculoskeletal anomalies which maybe bony, vascular or involving the ligaments and muscles which may have a direct or indirect impact on its pathoanatomy. This report describes an unusual presentation of a bifid tibialis anterior tendon (TAT) in a case of CTEV. This is the first report of this kind in the literature to the best of our knowledge. Case Report: A 4-year-old female presented with bilateral relapsed CTEV with dynamic supination previously treated with standard Ponseti protocol. The patient was treated with TAT transfer on the left side with a rare presentation of a bifid TAT where both the slips of the tendon were transferred to dorsum of the foot onto the lateral cuneiform. Conclusion: When treating a patient of CTEV surgically, it is important to consider the possibility of a bifid TAT which is a rare musculoskeletal association. It is recommended to carefully dissect TAT to prevent under correction of the deformity in case either one of the tendon slips remains attached to its original site.

Intraprosthetic Dislocation of Dual Mobility Total Hip Arthroplasty: A Case Report and Review of Literature.

Introduction: First introduced in Europe in the 1970s, dual mobility total hip arthroplasty (DM-THA) has gained popularity over years due to the reduced dislocation rates compared to standard THA. However, intraprosthetic dislocation (IPD), a rare complication where the femoral head separates from the polyethylene (PE) liner, remains a potential complication. Case Report: A 67-year-old female presented with a transcervical neck of femur fracture. She was managed with a DM-THA. She dislocated her THA on post-operative day 18. Closed reduction was performed for the same under general anesthesia. However, she again dislocated her hip 2 days later. CT scan was done and an IPD was diagnosed. The PE liner was revised and the patient had a good outcome at 1 year follow-up. Conclusion: When a DM-THA dislocates, it is important to consider the possibility of IPD which is a rare but unique complication associated with these systems. The recommended treatment for IPD is open reduction and replacement of the PE liner.