Options for revision in femoral neck fractures nonunion are arthroplasty or revision fixation with or without osteotomy. In the older patient, arthroplasty is the primary form of treatment, while a younger patient should be considered for revision fixation. There is no particular age at which revision fixation or arthroplasty should be done. Marti successfully performed osteotomies up to age 70, while arthroplasty surgeons have advocated replacement at age 60–65, especially as arthroplasty implants have improved and patients are less tolerant of lengthy rehabilitation [16, 19]. Careful consideration of expected clinical course and potential complications should be used in choosing treatment (Table 9.1) [26–34]. Revision fixation requires a healing period prior to the resumption of activities, which may last 3–6 months and does not guarantee success. However, it allows for preservation of the native hip joint. Even the presence of low-grade avascular necrosis is not a contraindication to hip preservation [15, 26, 31]. In the uncommon instance of biologic failure, the healing environment can be augmented by autogenous or vascularized bone graft. The Meyers graft [35, 36] which utilizes the bony insertion of the quadratus femoris placed into the posterior femoral neck or a vascularized fibula as advocated by LeCroy et al. [31] can provide the stimulus to achieve union.

Mechanical failure is most common with failure of fixation and development of a deformity on radiographic examination. In femoral neck nonunion attributed to mechanical failure, the principal decision is whether osteotomy will improve the mechanical environment. On analysis of the nonunion, the new construct must assure adequate stability in the face of physiologic forces to allow for healing. In the instance of a poorly placed initial construct, revision fixation alone may be considered. Cannulated screws in the most optimal position or a screw and side plate device with screw augmentation may allow for healing. Wu, in a mixed series with and without osteotomy, reported 100% healing in the group treated with a screw and side plate alone [34].

In high angle fractures often seen in the younger patient, an osteotomy is indicated when a nonunion develops. These nonunions are often associated with varus and shortening. Properly executed osteotomies result in union rate of 70–100% [26–29, 34]. As described by Pauwels, the osteotomy converts a vertically oriented fracture with shear to a more horizontal orientation creating compressive forces promoting union. In considering an osteotomy, the duration of healing along with alterations of anatomy must be considered. These alterations of shortening and a lesser abductor moment are generally well tolerated but should be discussed with the patient.

In this procedure, the nonunion is not exposed directly. A blade plate is most often used to compress the osteotomy, but a screw and side plate may also be used [28, 29, 34]. A blade plate is technically more demanding but offers proven stability while requiring only a narrow corridor of bone.

The critical step in performing the intertrochanteric osteotomy is preoperative planning (Fig. 9.4). The concept is to convert the angle of the fracture to less than 30° by performing an intertrochanteric osteotomy. Good anteroposterior pelvis and lateral hip views are required. The angle of the fracture to the horizontal is measured. Due to leg rotation, the precise angle may be hard to measure, but may be facilitated by measuring it to a line perpendicular to the femoral shaft [27]. A closing wedge osteotomy is planned to correct the angle of the fracture to less than 30°. In the case of a fracture angle of 70°, a wedge of 40° is planned.

The position of the blade plate that allows for adequate fixation is templated. Inevitably, the biomechanics of the hip are altered with some shortening of the neck and medialization of the shaft. Some modifications of the osteotomy have been proposed that can minimize the anatomic alterations. A combination of opening and closing wedge osteotomy or translating the shaft laterally along the osteotomy are methods used to limit biomechanical alterations but may carry a theoretic risk of nonunion.

The intertrochanteric osteotomy is executed on a radiolucent table. The surgeon must assure adequate radiographic visualization of the hip prior to create the sterile field. The proximal femur is exposed through a lateral approach, but the nonunion site is not opened. The previous hardware is removed. The projected osteotomy site is marked as well as the position of the fixation device. The pathway for proximal fixation should be established prior to the osteotomy since it is very difficult to place a blade plate after the osteotomy is completed. For a blade plate, a guide wire and drill bits establish the pathway for the chisel. The pathway starts on the greater trochanter skirts the piriformis fossa, across the nonunion and terminates in the inferior medial femoral head. The chisel is used to create a pathway for the blade plate. Frequent fluoroscopic views in both the anteroposterior and lateral views assure that correct placement.

The planned closing wedge osteotomy is marked with Kirschner wires. The proximal cut is parallel with the blade plate track and at least 1.5–2 cm distal to provide for a bone bridge. The osteotomy is then performed with a saw while cooling the blade with irrigation making sure not to cause thermal necrosis. It is also important to keep the osteotomy perpendicular to the shaft to avoid flexion or extension. The selected blade plate is seated, and then, the osteotomy is compressed with a compression device placed distally on the shaft. On the anteroposterior view, care is taken to avoid excessive medialization along the osteotomy as it contributes to not only to limb shortening but also to loss of abduction and valgus alignment of the knee. A longer blade and lateralization of the shaft limits this problem. Close attention is paid on the lateral view and rotation to assure that these are maintained in final fixation. Displacement in the lateral view will render subsequent arthroplasty if needed much more difficult. The harvested wedge is morselized and placed around the osteotomy site. Postoperatively, touch weight bearing and then protected weight bearing are allowed until healing is seen, usually in 3 months. Patients are cautioned that persistent limp and mild leg length difference are common while preserving the native hip.

Results of valgus intertrochantgeric osteotomy have been reported by a number of authors consistently reporting union from 70 to 100% of patients with avascular necrosis occurring around 20% [26–29, 34]. Marti et al. in a series of 50 patients with a mean age of 53 achieved a union rate of 86% [26]. Of 22 patients that had evidence of osteonecrosis without collapse only 3 progressed requiring arthroplasty. An additional 3 patients required arthroplasty for continued nonunion and one for periprosthetic fracture for an arthroplasty rate of 14% with a mean follow-up of 7 years. In this series, the Harris hip score was 91, while 78% were good or excellent on the Merle d’Aubigné score. Anglen had 100% union rate in 13 patients although 2 required arthroplasty by 2 years for osteonecrosis [27]. Ballmer et al. reported that in 17 patients, 71% healed following the index procedure while an additional 3 healed following additional bone grafting for an overall union rate of 88% [37]. Three, however, required subsequent arthroplasty for avascular necrosis. In Hartford et al.’s series of 8 patients treated with a sliding hip screw union was achieved in all cases and Harris hip score improved from 24 to 73 [29]. Another more recent series reported the use of a single-angled 130 degree plate [30]. In 36 patients (mean age 37), union was achieved in 97%, while 5 developed avascular necrosis. 61% reported no pain, and the average leg length deficit of 2.5 cm was corrected to 0.5 cm. The authors of this series felt that the single-angle plate limited medialization while optimizing length. Other authors, using the double-angle plate, have been able to control this problem by laterally translating the femur. Unfortunately, more detailed outcomes measures are not available to judge functional status or compare methods of treatment.

A vascularized fibular strut or vascular iliac crest has been proposed to enhance vascularity while correcting deformity and enhancing stability [31, 38, 39]. The fibular technique has been particularly advocated in nonunions with associated avascular necrosis provided the acetabulum is intact, but this is technically demanding and requires microvascular anastomosis.

The surgical technique described involves removal of hardware and revision fixation. Through a Watson-Jones approach, a channel is created in the lateral femur into the neck and head to accommodate the harvested fibula. The necrotic bone in the head if present is removed with special burrs. Correction of the femoral neck deformity is obtained from the mobility gained when the channel is created. The defect in the head is filled with cancellous bone from the greater trochanter. The fibula is placed into the head and neck and stabilized with a K-wire after the fibula is inserted. The critical vascular anastomosis is then performed. Further stability is obtained by placing cannulated screws parallel to the free fibula. Postoperatively the patient is nonweight bearing for 6 weeks and then gradually progressed thereafter. This technique is clearly technically demanding but is useful in the face of avascular necrosis.

The series reported by LeCroy et al. describes 22 patients (mean age 29) who underwent a vascularized fibula repair of a nonunion at a mean of 18 months following initial fixation [31]. Union was achieved in all patients at an average of 9 months but 2 required additional surgeries to achieve union. Osteonecrosis was present in all 22 cases at reconstruction surgery (predominantly Steinberg Stage II, 12 cases, but also Stage I, 4 cases; Stage III, 2 cases; Stage IV, 3 cases; even Stage V, 1 case). Despite osteonecrosis progressing in 13 patients, the native hip was retained in 20 patients with an average Harris hip score of 78.9. Although only 5 reported being able to participate in vigorous physical activity that included running, 16 were able to perform moderate activity.

Recently, an alternate method of free vascularized fibula was reported by Jun and colleagues [32]. In the reported series of 26 cases, the free fibula was inserted via an anterior approach into a trough facilitating placement and simplifying vascular re-anastomosis. Twenty-four healed at an average of 5 months. One case of postperative osteonecrosis was observed. Unlike the series of Lecroy where all had osteonecrosis, in this series only 1 patient had radiographic findings of osteonecrosis preoperatively. Outcomes were reported in terms of the Harris hip score, which improved on average to 87.9.

The use of nonvascular fibular grafts has been reported by Elgafy and associates in 19 cases with minimal varus malalignment [33]. In that small series, nonvascular fibular sutografts achieved union in 9 of 13 cases (69%). The same authors reported union in only 2 of 6 cases in which a fibular allograft was used. Despite the relative technical ease of such a technique, there is no advantage in using a nonvascular fibular strut in the treatment of femoral neck nonunion.

Arthoplasty particularly with modern bearing surfaces should be considered in femoral neck nonunion not only in the face of acetabular destruction or avascular necrosis. In the patient over 60, arthroplasty is likely to provide a reliable method to return the patient to activity but does not match the excellent results achieved with primary arthroplasty for osteoarthritis. Although in the series of Marti et al. osteotomy was generally preferred in patients up to age 70 [26] and by Hitt to age 60 [19], modern techniques and implants have lowered the age in which arthroplasty is considered. Particularly in the younger patient, considerations should include the potential for infection, dislocation, and periprosthetic fracture. Although the incidence for each of these complications is low, for the patient with an infection, for instance, the outcomes are greatly diminished. It is well established that arthroplasty in the face of previous surgery raises the risk of infection [40].