Early fixation failure in displaced femoral neck fractures

Fracture morphology of high shear angle "vertical" femoral neck fractures in young adult patients

OBJECTIVE

Management of vertical femoral neck fractures in young adults has been a challenging clinical problem, resulting in mixed clinical outcomes. A thorough understanding of the fracture morphology for this injury pattern is lacking, which may contribute to frequent failures of treatment. This study is designed to produce a detailed description of the pathoanatomy of these fractures, which may ultimately be helpful in developing more informed reduction and fixation strategies.

DESIGN

Retrospective study of patient records, plain radiographs, and computed tomography scans to determine the morphology the Pauwels III femoral neck fractures (coronal angle >50 degrees) in young adults.

SETTING

Two level I and 1 level II regional trauma centers.

PATIENTS

All patients 18-49 years of age with a surgically repaired, high-energy high shear angle (>50 degrees) femoral neck fracture from January 1, 2007, to December 31, 2010.

METHODS

One hundred thirty-six adult patients younger than 50 years were identified with a femoral neck fracture in the study period, of whom 33 met all study criteria. We evaluated plain radiography and computed tomography data including fracture orientation, comminution, deformity, characteristics of the inferomedial fracture spike, and the associated inferomedial calcar's cortical buttress.

RESULTS

The vertical (coronal) fracture averaged 60 degrees and axial fracture obliquity averaged 24 degrees with relative deficiency of the posterior neck on the head-neck fragment. Major femoral neck comminution (>1.5 cm in any dimension) was identified in 96% of cases, mostly located in the inferior (94%) and posterior (82%) quadrants. The apical fracture spike of the head segment was found to be in line (within 10 degrees) of the neck-shaft axis on the proximal femur 63% of the time. Deformity in external rotation averaged 44 degrees (range, 10-68 degrees) and shortening of the femur averaged 1.8 cm (range, 0.9-4.4 cm).

CONCLUSIONS

This study investigated the fracture morphology of isolated, high shear angle femoral neck fractures in young adults, which may ultimately lead to improved operative reduction and fixation tactics. Given this injury's characteristic findings, including fracture orientation, deformity, and comminution, surgeons should be cognizant of this pattern's innate instability and potential for treatment failure with typical implant constructs.

Internally fixed femoral neck fractures. Early prediction of failure in 203 elderly patients with displaced fractures

After internal fixation of a femoral neck fracture, 3 months is the critical time for planning rehabilitation of the patient. Most failures in the elderly occur within this time. In a series of 165 patients, we followed 127 women and 38 men with a median age of 81 (63-97) years from an examination at 3 months to reoperation or survival of the hip. 36 patients had radiographic signs of disturbed healing at the 3-month follow-up--change in fracture position by 10 mm, change in screw position by 5%, backing of the screws by 20 mm, or perforation of the femoral head by the screw. These signs had a high association with local complications and need for a later reoperation. High age and male sex increased this association. Signs of impaired healing made nonunion likely, but did not predict late segmental collapse of the femoral head. Patients with signs of disturbed healing and those closest to them should be informed about the value of early check-ups in case of pain and impaired function.

Hip Fractures: I. Overview and Evaluation and Treatment of Femoral-Neck Fractures

Hip fractures remain a major source of morbidity and mortality in the elderly, and their incidence is increasing as the population ages. Surgical management followed by early mobilization is the treatment of choice for most patients with hip fractures. However, all comorbid medical conditions, particularly cardiopulmonary and fluid- electrolyte imbalances, must be evaluated and stabilized prior to operative intervention. Nondisplaced femoral-neck fractures should be stabilized with multiple parallel lag screws or pins. The treatment of displaced femoral-neck fractures is based on the patient's age and activity level: young active patients should undergo open reduction and internal fixation; older, less active patients are usually treated with hemiarthroplasty, either uncemented or cemented. Regardless of treatment method, the goal is to return the patient to his or her prefracture level of function.

Outcomes after displaced fractures of the femoral neck. A meta-analysis of one hundred and six published reports

Methods of meta-analysis, a technique for the combination of data from multiple sources, were applied to analyze 106 reports of the treatment of displaced fractures of the femoral neck. Two years or less after primary internal fixation of a displaced fracture of the femoral neck, a non-union had developed in 33 per cent of the patients and avascular necrosis, in 16 per cent. The rate of performance of a second operation within two years ranged from 20 to 36 per cent after internal fixation and from 6 to 18 per cent after hemiarthroplasty (relative risk, 2.6; 95 per cent confidence interval, 1.4 to 4.6). Conversion to an arthroplasty was the most common reoperation after internal fixation and accounted for about two-thirds of these procedures. The remaining one-third of the reoperations were for removal of the implant or revision of the internal fixation. For the patients who had had a hemiarthroplasty, the most common reoperations were conversion to a total hip replacement, removal or revision of the prosthesis, and débridement of the wound. Although we observed an increase in the rate of mortality at thirty days after primary hemiarthroplasty compared with that after primary internal fixation, the difference was not significant (p = 0.22) and did not persist beyond three months. The absolute difference in perioperative mortality between the two groups was small. An anterior operative approach for arthroplasty consistently was associated with a lower rate of mortality at two months than was a posterior approach. Some reports showed promising results after total hip replacement for displaced fractures of the femoral neck; however, randomized clinical trials are still needed to establish the value of this treatment.

Implant/bone constructs in femoral neck osteotomy. An autopsy study

Previous studies have suggested that three rather than two screws may give better results in the treatment of femoral neck fractures. In the present study, the strength of various screw/bone constructs in femoral neck osteotomy was analyzed. Transverse osteotomies on 65 cadaver femora were fixed with two or three screws of two types: one with a shank diameter of 6 mm and thread diameter of 8 mm, and a prototype screw with equal shank and thread diameter of 7 mm. The femoral heads were subjected to static and cyclic loads in the one-legged stance position. Single-energy quantitative computed tomography measurements were correlated to load. The two experimental models resulted in different patterns of failure of the bone/implant constructs, otherwise the results were similar. Three of the prototype screws gave the strongest construct, while two of the other screw type were stronger than three. The explanations for the diverging properties of the different bone/implant constructs may be that large threads destroy too much of the bone trabeculae, and that screw threads larger than the shank may destroy the drill canal and produce an unstable situation compared with screws with equal shank and thread diameter.

Early loss of fixation of femoral neck fractures. Comparison of three devices in 244 cases

In successive series of displaced subcapital femoral neck fractures in the elderly, we operated on 75 cases with three Gouffon screws, 94 with three Mecron screws, and 75 with two von Bahr screws. Redisplacement within 3 months occurred in 20 Gouffon cases, 11 Mecron cases, and 12 von Bahr cases. Poor reduction contributed to the failures in all the groups. Although the reduction results in the three groups were similar, the Mecron group had better fixation and better social recovery than the Gouffon group. We concluded that, in addition to good reduction of the fracture, solid screws also contributed to the stability of the bone-implant construct.