Most traumatic instability can be treated nonoperatively. Of course, dislocations require emergent reduction to minimize the risk of developing avascular necrosis of the femoral head. Unless there is a compelling reason for arthroscopic intervention, such as a nonconcentric reduction or obvious entrapped fragment, an initial trial of conservative treatment is preferable. Three months is a reasonable time frame for resolution of the acute phase of the injury and a clearer assessment of whether an athlete continues to have mechanical symptoms or clinical findings that may warrant arthroscopic intervention. In addition to subsidence of acute symptoms, this is an opportunity for some intra-articular damage to declare itself. For example, impaction injury to the articular surface of the femoral head may lead to subsequent chondrocyte cell death and articular delamination that may not be evidently close to the time of the initial injury. Arthroscopy , at a later date, may provide a clearer reflection of the severity of intra-articular pathology. Often the injuries heal, arthroscopy is not necessary, and athletes can resume sporting activities without symptoms. Long-term consequences may still be less certain, and thus athletes are educated about warning signs of symptoms that might warrant reevaluation in the future.

The presence of a posterior rim fracture does little to alter the treatment strategy, or likely outcomes, of posterior subluxation episodes. The fracture may only partially heal or develop a fibrous union, but this is rarely a source of residual symptoms or cause for surgical intervention. Surgery is usually necessitated due to other intra-articular pathology.

Most patients with posterior subluxations recover well and can resume athletic activities (Fig. 2). However, some do poorly, with rapidly progressive joint deterioration, and can be facing an arthroplasty even within a year of the index injury (Fig. 3). There are few indicators to predict which will do well and which may rapidly decline. Thus, a deliberate, responsible rehab strategy is important for all cases. A protocol is outlined in Table 1. Protective weight bearing is maintained for 4 weeks, during which time hip flexion is limited to 90°. A follow-up MRI is performed at 1 month, looking for resolution of soft tissue edema and any joint effusion. Subchondral edema may start to develop in the femoral head as an indication of the impaction injury to the joint surface. This is common and is not necessarily a harbinger of poor results or an indication of early AVN [19]. In the cases of posterior rim fractures, a follow-up CT scan can be helpful just to assure that no further displacement has occurred. Loaded hip flexion is avoided until 6 weeks, and then the athlete is progressed with a functional program as symptoms allow. Return to unrestricted activities at 8–10 weeks is not unreasonable, as long as the athlete remains pain-free. A later MRI may be obtained to rule out signs of late onset avascular necrosis.

There are many complex fractures that may warrant early ORIF, but that is not the subject of this chapter. Early arthroscopy may be indicated for a nonconcentric reduction or entrapped fragments (Fig. 4). Commonly, arthroscopy will reveal more extensive damage than that identified by the imaging. This tendency of MRI to underestimate the damage should be kept in mind, as some athletes who fail to respond to conservative care may have more occult joint pathology. The timing of surgery should also take into consideration concerns about soft tissue extravasation. Normally, the risk of extravasation should not be any greater than that encountered in association with other extensive arthroscopic procedures to correct FAI that often involve large capsular exposures. Early arthroscopy should be avoided when there is an acetabular fracture that communicates with the intrapelvic region [20].