Hyponatremia is common after orthopaedic surgeries. The prevalence of hyponatremia in the postoperative period is 25-40% in elderly patients. It can cause serious and potentially life threatening complications. Identifying the cause (etiology) and providing appropriate treatment can mitigate the adverse effects of hyponatremia. Depending on the underlying cause, the treatment of hyponatremia can be markedly different. The aim of the study is to determine the cause of post-operative orthopaedic hyponatremia. Methods: This is a prospective study of adults aged more than 65 years admitted with major lower limb fractures who developed post-operative hyponatremia. ECF volulme status was assessed by clinical examination and biochemical parameters. Results: Thirty five patients developed post-operative hyponatremia. The most common cause of postoperative orthopaedic hyponatremia was hypovolemia 45.71% (n=16), followed by euvolemia (SIADH) in 25.71% (n=9). Acute kidney injury, hypervolemia and medications each in 3 cases (8.57% each), hypotonic fluids in one case. Etiology was multifactorial in 77.14% (n=27). Conclusions: Hypovolemia and euvolemia with SIADH are the two major causes of hyponatremia after orthopaedic surgery. The treatment requirements are exact opposites. Hypovolemia requires rehydration with IV fluids where as SIADH needs fluid (free water) restriction. Understanding the etiology of hyponatremia helps to treat hyponatremia with optimal use of IV fluids and avoids adverse outcomes.

Thirty patients with comminuted intra-atricular fractures of the distal end radius, less than 65 years old (mean age 38 years) have been treated by external fixation. Fractures were classified according to Frykman's Classification. Radiological results were assessed using stewart's criteria. Functional results were evaluated with Demerit point system of Gartland and werly as modified by Sarmiento. It improves extra-articular alignment (radial angle, radial length and Volar tilt). The articular surface was restored to normal congruity or to within 1mm step-off in 23 patients. Only three patients had step-off more than 2 mm. The most common complications were pintract infections in three patients and radial nerve neuritis in two cases. At mean follow-up of twenty-five months anatomical results and functional results were good to excellent in 83.33%(n=25) and 86.66%(n=26) respectively. Anatomical results correlated with functional results. Results suggest that the external fixation gives better anatomical and functional results and remains a viable surgical alternative for management of comminuted intra-articular displaced distal radius fracture.