The effect of early weight-bearing on the stability of femoral neck fractures treated with Knowles pins

Biomechanical rationale for implant choices in femoral neck fracture fixation in the non-elderly

Femoral neck fractures represent a relatively uncommon injury in the non-elderly population often resulting from high-energy trauma. The cornerstone of their management is anatomic reduction and stable internal fixation of the femoral neck in an attempt to salvage the femoral head. Complications including avascular necrosis of the femoral head, non-union and post-traumatic osteoarthritis are not uncommon. The clinical outcomes of these patients can be improved with good pre-operative planning, optimization of surgical procedures and introduction of new improved implants and techniques. In the herein study, we attempt to describe the biomechanical properties of the hip and compare the performance of the most commonly used devices. Experimental evidence suggests that in Pauwels type III fracture patterns a cephalomedullary nail was significantly stronger in axial loading. Moreover, in unstable basicervical patterns cannulated screws (triangular configuration) demonstrated a lower ultimate load to failure, whereas in subcapital or transervical patterns both the cannulated screws (triangular configuration) and the sliding hip screw demonstrated no compromise in fixation strength. The fracture pattern appears to be the major determinant of the ideal type of implant to be selected. For a successful outcome each patient needs to be considered on an individual basis taking into account all patient and implant related factors.

Dynamic hip screw for the treatment of femoral neck fractures: a prospective study with 96 patients

Objectives. To study the correlation between avascular necrosis and the demographics, time elapsed from fracture to surgery, quality of reduction, Garden classification, and the position of the screw following use of the dynamic hip screw (DHS) in the treatment of subcapital neck fractures. Methods. A prospective study of 96 patients with subcapital neck fractures was carried out in a faculty hospital. Patients underwent surgery with closed reduction and internal fixation with DHS. Results. There were 58% male and 42% female patients, with a mean age of 53 years (+/−14). In terms of Garden classification, 60% were Garden IV, 26% were Garden III, and 14% were Garden II. Nonunion was observed in three cases (3%) and was treated with valgus intertrochanteric osteotomy, in all cases leading to successful healing. Avascular necrosis was observed in 16% of patients. The positioning of the screw into the femoral head showed a significant correlation with necrosis. Conclusions. The incidence of necrosis in patients under the age of 50 years is twice as high as that in older patients. Displacement is a predictive factor regarding osteonecrosis and is associated with a high and anterior position of the screw in the femoral head. Level II of evidence. Study Type: therapeutic study.

Can we improve fixation and outcomes in the treatment of femoral neck fractures? The use of pharmaceuticals

Femoral neck fracture rates are on the rise with an estimated 500,000 occurring annually by 2040. Despite the mainstay of open reduction and internal fixation, nonunion rates of up to 33% have been reported for displaced femoral neck fractures. Recently, increasing attention has been focused upon the role of osteobiologics to stimulate fracture repair. This article looks at the role of these anabolic compounds and discusses their potential future roles in augmenting the treatment of this condition.

A predictive method for subsequent avascular necrosis of the femoral head (AVNFH) by observation of bleeding from the cannulated screw used for fixation of intracapsular femoral neck fractures

OBJECTIVES

To examine the validity of bleeding from the drill holes used for cannulated screw placement as a method for predicting any subsequent avascular necrosis of the femoral head (AVNFH) after the fixation of intracapsular femoral neck fractures.

DESIGN

Retrospective study.

SETTING

University hospital.

PARTICIPANTS

Forty-four patients (mean age, 51 years; range, 18-76 years) whose femoral neck fractures had been fixed with cannulated screws from March 1999 to January 2001 were enrolled in this study. The fractures were classified according to Garden and included 11 type I, 5 type II, 17 type III, and 11 type IV. The average delay between injury and surgery was 52 hours (< or =24 hours, 26; > or =24 hours, 18; range 7 to 504 hours). The follow-up period was more than 25 months (range, 25-57 months).

INTERVENTION

7.0 mm cannulated screws were used for fracture fixation. Three and 4 screws were used for fixation in 35 and 9 cases, respectively.

MAIN OUTCOME MEASUREMENTS

The presence or absence of blood drainage from the holes of the proximal cannulated screws was determined by an independent observer and defined as bleeding or no bleeding throughout a 5 minute observation period. According to those findings, patients were classified into 2 groups: the bleeding group (38 cases), and the nonbleeding group (6 cases). The validity of the relationship between the 2 groups and the development of AVNFH was evaluated according to the sensitivity, specificity, positive predictive value, and negative predictive value. A chi test was used for univariate analysis of the relationship between the related factors with the development of AVNFH.

RESULTS

The mean follow-up was 39 months (range, 25-57 months). AVNFH developed in 7 cases (16%). One patient of 38 in the bleeding group (2.6%) and all 6 patients in the nonbleeding group (100%) developed AVNFH. The sensitivity was 86%, specificity 100%, positive predictive value 100%, and negative predictive value 97%. Age (P < 0.734), sex (P < 0.587), the type of the fracture (P < 0.356), procedure interval (P < 0.398), the reduction status of the fracture site (P < 0.3849), the positions of the fixed screws (P < 0.2137), and the existence of osteoporosis (P < 0.4347) were not related to the development of AVNFH.

CONCLUSION

It seems that bleeding from the holes of proximal cannulated screws is a simple and accurate perfusion assessment technique for predicting the development of AVNFH after a femoral neck fracture. Given that assumption, primary arthroplasty might be an appropriate choice as a treatment method in a nonbleeding-group patient whose treatment choice is ambivalent or who might not be able to undergo additional surgery should he or she develop a subsequent AVNFH after internal fixation of femoral neck fracture.

DVT prophylaxis and anticoagulation in the surgical patient

One of the most common postoperative complications is venous thromboembolism, a term encompassing deep vein thrombosis and pulmonary embolism. This article reviews the epidemiology, natural history, difficulties in diagnosis, and strategies for the prevention of postoperative venous thromboembolism. We thoroughly review the currently available methods for thromboprophylaxis including: early ambulation, elastic compression stockings, pneumatic compression devices, inferior vena cava filters, and a variety of pharmacologic agents such as unfractionated heparin, warfarin, aspirin, low molecular weight heparin, and pentasaccharides. Finally, we review the perioperative management of patients on long-term oral anticoagulation.

Biomechanical factors and failure of transcervical hip fracture repair

OBJECTIVE

To assess the association between biomechanical measurements (bone quality of the femoral neck, comminution, fracture angle, and fracture level) and the likelihood of fixation failure among patients who have a multiple screw stabilisation of an intracapsular hip fracture.

METHODS

A cohort study of 139 Washington State residents greater than 60 years of age who sustained a fall-related transcervical hip fracture treated from 1990 to 1996 inclusive. Measurements of bone quality, fracture angle, fracture level, and comminution were taken from perioperative X-rays. The outcome measure was clinical failure of the internal fixation procedure within 12 months of hospital discharge, as measured by readmission for further surgery to that hip.

RESULTS

Of the four biomechanical aspects examined, only bone quality, as measured by presence of an ICD code for osteoporosis, was significantly associated with risk of subsequent hospitalisation for revision surgery (adjusted hazard ratio 7.7, 95% CI 1.8-32.8).

CONCLUSION

A diagnosis code for osteoporosis was related to the outcome of intracapsular fractures repaired with multiple pins. Other biomechanical measurements from diagnostic X-rays were not related to the need for further surgery.

The effect of femoral neck fractures on femoral head blood flow

Treatment of femoral neck fractures remains a significant clinical challenge. The choice between femoral head replacement and internal fixation must take into account the patient's age, activity level, degree of osteoporosis, and medical condition. If open reduction and internal fixation is chosen, an understanding of the vascular pathophysiology of femoral neck fractures is helpful to insure the best clinical result. Osteonecrosis of the femoral head and non-union of the femoral neck fracture are the two most common complications following fixation of a femoral neck fracture. The vascular damage from the fracture itself significantly reduces femoral head perfusion. Therefore, a careful and anatomic (or slightly valgus) reduction, followed by rigid fixation with three pins, three screws, or a hip screw construct, is advised. There is experimental and clinical evidence that "emergent" open reduction and internal fixation and capsulotomy may lessen the vascular insult from the femoral neck fracture itself.

Weight bearing after hip fracture: a prospective series of 596 geriatric hip fracture patients

Five hundred ninety-six patients age > or = 65 with femoral neck or intertrochanteric fractures were allowed immediate unrestricted weight bearing after surgery and were prospectively followed. Follow-up data and hospital records were examined to identify those patients who required additional hip surgery owing to failure of fixation, nonunion, osteonecrosis, or prosthetic dislocation. Four hundred seventy-three patients were available for 1-year minimum follow-up; 16 patients (3.4%) required additional hip surgery. The revision surgery rate after intertrochanteric fracture due to loss of fixation was 2.9%. The revision surgery rate after internal fixation of the femoral neck from loss of fixation/nonunion was 5.3%; the revision rate from osteonecrosis for patients with 2-year follow-up was 5.4%. The revision rate after hemiarthroplasty due to prosthetic dislocation was 0.6%. These results support the use of unrestricted weight bearing in elderly patients after hip fracture surgery.

Breakage of Knowles pins used for femoral neck fractures

We report the breakage of multiple Knowles pins in two patients with fractures of the femoral neck. The break occurred at the junction of the threaded and smooth sections of the pins before consolidation of the fracture.

Nailing of femoral neck fracture. Clinical and sociologic 5-year follow-up of 510 consecutive hips

In a retrospective population-based study, 510 consecutive cervical hip fractures treated by internal fixation with a spring-loaded four-flanged nail, early weight bearing, and social rehabilitation were examined at 5 years after primary nailing. Six (1.6 percent) deep infections occurred. After a new trauma, seven fractures through the nail entrance were seen. Mortality at 2 years was 32 percent and at 5 years 53 percent. With a program for active rehabilitation, 80 percent of the survivors coming from independent living returned to this and remained there. The frequency of reoperations in patients below age 70 years was twice as high as in those over 70. Secondary arthroplasty was performed in 6 percent of the 129 undisplaced fractures and in 25 percent of the 381 displaced fractures. Totally, 67 percent of the fractures had no secondary procedure, not even nail extraction.