All articular fractures should be surgically repaired. Why? Incongruence is the number one reason for osteoarthritis (OA) to develop in a joint. So if a joint is fractured and not put back together in a near perfect manner then the joint will be incongruent. The amount and rapidity with which the OA will ensue will be proportional to degree of incongruence. Hence surgical repair can help minimize the OA (but not prevent it from occurring as we already have trauma, and surgery is yet another trauma – OA management workshop coming soon).
To conclude, strongly recommend/push for surgical repair if you are dealing with an articular fracture, as this will result in the very best outcome for your patient. If surgery is not an option and displacement is not huge, then I would try conservative management (splint, rest and pain medications) before considering an amputation. If the fracture is in the coxofemoral joint (capital physeal, acetabular, femoral neck) then consider a Femoral Head Ostectomy (see FHO workshop here).