OPTIONS

Displaced femoral neck fractures in the young adult patient tend to result from high-energy trauma. Typically, this produces a highly unstable vertical shear fracture and is often associated with other injuries (e.g., ipsilateral femoral shaft fracture).^3–5 This high-energy mechanism may also result in significant injury to the soft tissues surrounding the hip joint. Cadaveric injection studies and radioisotope scans of the femoral head show that there are both intraosseous and extraosseous vessels supplying the femoral head and neck.^6,7 The major extraosseous blood supply to the femoral head comes from the medial femoral circumflex artery and its retinacular branches (inferior, posterior, and superior). The artery of the ligamentum teres supplies a negligible volume of the femoral head in most of the population. In displaced femoral neck fractures, blood supply to the femoral head and neck is mainly dependant on the extraosseous retinacular branches of the medial femoral circumflex. Several questions become apparent: Does nonunion and avascular necrosis depend on the extent of damage to these vessels at the time of injury and not the time from injury to operative fixation in high-energy injuries? Do high-energy injuries have greater rates of nonunion and avascular necrosis than low-energy injuries?

Several authors have discussed the possibility that avascular necrosis of the femoral head is related to increased intracapsular pressure.^8,9 Increased intracapsular pressure may result in occlusion of the retinacular vessels. This has often been the argument for early surgical intervention or aspiration to “decompress” the hip capsule. Are rates of avascular necrosis affected by hip capsule decompression?

Low-energy injuries may occur in the young adult. Robinson and colleagues³ and Swiontkowski and coauthors⁴ comment on a subgroup of patients from this population who have longstanding medical problems and sustain this fracture from a simple fall. They found that these patients tended to have an increased prevalence of alcoholism, arthritis, cardiorespiratory problems, neuromuscular disorders, and epilepsy. Is this subgroup of patients best grouped with elderly patients because their fractures likely occur secondary to osteoporosis and result from low-energy trauma?

Displaced femoral neck fractures in the elderly have been examined mainly from the standpoint of treatment. A lack of agreement remains among surgeons regarding optimal treatment (internal fixation vs. arthroplasty) for those fractures in the young elderly group (i.e., 60–80 years of age).¹⁰ Internal fixation of the fracture in this age group has several advantages compared with arthroplasty: shorter operative time, decreased blood loss, and reduced perioperative mortality.¹¹ Many of these patients have significant comorbidities and require medical management before surgery. Does time from injury to surgery affect the rates of nonunion and avascular necrosis in elderly patients with displaced femoral neck fractures?

EVIDENCE

Damany and coauthors² reported a meta-analysis on intracapsular femoral neck fractures in the young adult (15–50 years of age). This is Level II evidence because they incorporated the results of 18 retrospective cohort studies (547 fractures) published between 1976 and 2003. They found that displaced femoral neck fractures occurred more frequently than nondisplaced fractures (79.9% vs. 25.6%) in this age group. The overall rate of avascular necrosis for the displaced fractures was 22.5%, and the rate of nonunion was 6.0%. They identified 7 studies (170 fractures) that gave data regarding timing of surgery and development of complications. From their analysis of these data, they found no significant difference in the rate of avascular necrosis for fractures reduced within 12 hours of injury (13.6%) as compared with those reduced after 12 hours (15%) of injury. Similarly, there was no difference in nonunion rates between the 2 groups (11.8% before 12 hours and 5.0% after 12 hours). This study represents the best evidence on timing of surgery and complications for displaced femoral neck fractures (Table 60-1).

Upadhyay and investigators’¹² Level II study found no evidence of decreased complication rates with early intervention among 92 young adults with displaced femoral neck fractures. Rates of avascular necrosis were 14% in the group treated within 48 hours of injury and 19% in the group treated over 48 hours after injury. The nonunion rate was 18% in the early treatment group and 16.7% in the delayed group. Haidukewych and colleagues’¹³ Level IV study also found no association between operative delay and complication rates.

Several Level II studies included in the meta-analysis by Damany and coauthors² conclude that the time interval between injury and surgery does affect complication rates. Swiontkowski and coauthors⁴ conclude that their good results (no nonunions and 20% rate of avascular necrosis) were due to early intervention. However, their sample size was small (21 patients) and included 4 nondisplaced fractures and only 1 displaced fracture treated over 12 hours after injury. Jain and colleagues¹⁴