Total hip arthroplasty can be a very effective salvage treatment for both failed fracture surgery and hip arthritis that may occur after prior fracture surgery. The rate of complications is significantly increased including especially infection, dislocation, and loosening. Complications are more likely to occur after failed open reduction and internal fixation than after posttraumatic arthritis. Adequately ruling out infection before hip arthroplasty can be difficult. The best predictor of infection is a prior infection. Long-term outcomes can be comparable to outcomes in other conditions if complications are avoided.
Key points
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Total hip arthroplasty can be a very effective salvage treatment for both failed fracture surgery and hip arthritis that may occur after prior fracture surgery.
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The rate of complications is significantly increased including especially infection, dislocation, and loosening.
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Complications are more likely to occur after failed open reduction and internal fixation than after posttraumatic arthritis.
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Adequately ruling out infection before hip arthroplasty can be difficult. The best predictor of infection is a prior infection.
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Long-term outcomes can be comparable to outcomes in other conditions if complications are avoided.
Introduction
Total hip arthroplasty (THA) is a very effective treatment option for both posttraumatic arthritis that can occur after prior hip fracture surgery and failed hip fracture fixation. Modern acetabular fracture surgery techniques can result in hip preservation and excellent long-term functional outcomes in 70% to 80% of cases. Higher-energy fracture patterns, significant articular impaction, and failure to achieve an anatomic reduction can predispose patients to the development of secondary hip arthritis. In patients who are physiologically fit and have failed conservative management, THA can provide appropriate pain control and functional restoration.
Avascular necrosis and nonunion after femoral neck fracture surgery, which may occur in 15% to 20% of cases, can also be effectively treated with hip replacement. Younger patients with a femoral neck nonunion but with a preserved hip joint can be treated successfully with a valgus intertrochanteric osteotomy. A less common cause of hip posttraumatic arthritis is the femoral head fracture, which may lead to avascular necrosis oftentimes related to an initial traumatic dislocation.
Hip replacement can also be used as a salvage for failed hip fracture surgery. If the hip can be saved by revision fixation, it is usually recommended first. Successful functional outcomes with a low rate of complications have been reported with revision internal fixation. If the joint is not preserved, then arthroplasty or arthrodesis is the principal surgical option. In cases of older patients with poor bone quality, arthroplasty may be preferable to revision fixation even if the joint is preserved. The published results of THA and hemiarthroplasty in this setting have also been very good with a low rate of serious complications. Rarely, resection arthroplasty should be considered in very ill patients or as a salvage in difficult-to-control infections.
Introduction
Total hip arthroplasty (THA) is a very effective treatment option for both posttraumatic arthritis that can occur after prior hip fracture surgery and failed hip fracture fixation. Modern acetabular fracture surgery techniques can result in hip preservation and excellent long-term functional outcomes in 70% to 80% of cases. Higher-energy fracture patterns, significant articular impaction, and failure to achieve an anatomic reduction can predispose patients to the development of secondary hip arthritis. In patients who are physiologically fit and have failed conservative management, THA can provide appropriate pain control and functional restoration.
Avascular necrosis and nonunion after femoral neck fracture surgery, which may occur in 15% to 20% of cases, can also be effectively treated with hip replacement. Younger patients with a femoral neck nonunion but with a preserved hip joint can be treated successfully with a valgus intertrochanteric osteotomy. A less common cause of hip posttraumatic arthritis is the femoral head fracture, which may lead to avascular necrosis oftentimes related to an initial traumatic dislocation.
Hip replacement can also be used as a salvage for failed hip fracture surgery. If the hip can be saved by revision fixation, it is usually recommended first. Successful functional outcomes with a low rate of complications have been reported with revision internal fixation. If the joint is not preserved, then arthroplasty or arthrodesis is the principal surgical option. In cases of older patients with poor bone quality, arthroplasty may be preferable to revision fixation even if the joint is preserved. The published results of THA and hemiarthroplasty in this setting have also been very good with a low rate of serious complications. Rarely, resection arthroplasty should be considered in very ill patients or as a salvage in difficult-to-control infections.
Indications and contraindications
Patients with significant hip pain with severe arthritis may be candidates for surgery ( Fig. 1 ). In the absence of gross implant instability or nonunion, these patients should generally be tried on a nonoperative treatment protocol that includes some combination of antiinflammatories, conditioning, and lifestyle modification before considering surgery. Patients with findings of significant arthritis on radiographs can sometimes function relatively well for years.
In the absence of end-stage arthritis, but in the presence of hardware failure, revision fixation may be an option in otherwise healthy patients. The decision about whether to proceed with revision fixation or hip arthroplasty should be made based on the patient’s age and functional status as well as radiographic findings including bone quality. In lower-demand patients, hemiarthroplasty is also an option. Hip fusion is less commonly used now in the younger patient population because of improvements in joint replacement technology. The only absolute surgical contraindication to arthroplasty is an ongoing active infection ( Table 1 ).
| Indications | Contraindications |
|---|---|
| Posttraumatic hip arthritis | Active infection |
| Avascular necrosis of the hip | Severe medical comorbidities |
| Proximal femoral nonunion | Fracture amenable to revision fixation |
| Loss of fracture fixation | Morbid obesity (BMI >45) |
Surgical evaluation and techniques and procedures
Medical Evaluation
Surgical assessment begins with optimizing the patient medically for surgery. Routine laboratory studies are performed, and patients are seen by their primary care physicians. The authors routinely recommend that patients address general health issues as listed in Box 1 before elective surgery.
Dental assessment
Smoking cessation
Local skin issues at the surgical site
Diabetes control
Hold certain medications (eg, plavix, therapeutic monoclonal antibodies for RA, methotrexate)
Weight loss if possible (our usual cutoff for surgery is BMI 40–45)
Abbreviations: BMI, body mass index; RA, rheumatoid arthritis.
Orthopedic Workup
A careful history and physical examination should be performed. Particular attention should be paid to the condition of the abductors (although this is often hard to assess because of pain) and any leg length discrepancy (LLD). A significant leg length difference may be difficult to completely correct at the time of surgery without placing the sciatic nerve at risk.
All patients are carefully screened for infection ( Fig. 2 ). If the erythrocyte sedimentation rate and C-reactive protein levels are abnormal or suspicion is prompted by history, examination, or radiographs, a hip aspiration is helpful. Unfortunately, in these cases, unlike revision hip arthroplasty, the presence of a smoldering infection often does not communicate with the joint, making the aspiration less reliable. If an infection is strongly suspected, the decision regarding how to proceed can be made based on frozen section analysis at surgery or the decision in some cases can be made a priori to proceed with a staged reconstruction ( Figs. 3 and 4 ). The following aspects of the history should arouse concern:
Any history of infection
Any history of prolonged wound drainage
Any history of repeat surgery for hematoma or seroma
Sudden increase in pain or decline in function and sudden loss of joint space
Extensive periosteal reaction
Periimplant osteolysis
Radiographic Assessment
Bony anatomy should be assessed with pelvic and hip radiographs that show the full extent of the bone that will be instrumented with the planned arthroplasty. The pelvic radiograph is useful in assessing limb length. Oblique radiographs (Judet views) can be useful in defining areas of structural deficiency in the columns and looking for a pelvic discontinuity. Computed tomographic scans are not required but can help in this regard, although frequently scatter from implants degrades the image quality.
Equipment Preparation: Planning for Problems
Every attempt should be made from the radiographs and the medical record to identify exactly what implants are present to facilitate removal. Additional extraction equipment such as a standard broken screw removal set and a metal-cutting high-speed burr should be available at surgery. Appropriate implants should be templated ahead of time, but one should have on-hand bail-out implants for possible intraoperative problems including periprosthetic femur fracture, acetabular deficiencies including discontinuity, abductor deficiency leading to instability, and operative findings suggesting infection.
Preparation and Patient Positioning
The patient is positioned in the lateral decubitus position on a fully radiolucent operating table with an axillary roll made with a sheet wrapped around a 1-L bag of saline and the down limb padded. The authors prefer to use a peg board but a beanbag positioner may be used. Fluoroscopic imaging should be obtained before the skin preparation to assure proper imaging. Leg lengths should be clinically compared in the supine and lateral position preoperatively because placement in the lateral position will frequently make it appear that the upper leg is shorter than it actually is because of its adducted position. Although clinical judgment of the limb length by palpation in the lateral position is difficult, the authors routinely perform this test as one more way to confirm appropriate length. Skin preparation is with alcohol, followed by a routine chlorhexidine/alcohol combination antiseptic.
Surgical Approach
No single surgical approach can be recommended based on the literature. Most investigators recommend basing the decision about approach on the prior surgical approaches, the existence of heterotopic ossification (HO) or contractures, and the surgeon’s preference. The authors’ customary approach is the utilitarian posterolateral approach, which is used for virtually all the complex reconstructions that they perform. Through this approach virtually all hardware can be removed and all bony deficits addressed. Rarely intrapelvic hardware needs to be removed via an ilioinguinal or Stoppa approach separately. Other investigators have reported excellent results with the anterolateral approach and the transtrochanteric approach, although, as might be expected, complications with regard to trochanteric fixation have been reported. A digastric osteotomy of the trochanter can be used to extend the surgical approach, which is especially useful after prior intertrochanteric fractures. Regardless of the approach, the published literature suggests that these cases can be exceedingly difficult with reported surgical times of 2 to 6 hours.
Surgical procedure: after prior acetabular open reduction and internal fixation
Step 1: Initial Exposure
The prior scar is incised and extended as needed. If the prior scar is wide and friable, it is routinely excised. The fascia lata is divided in line with the wound being cautious not to denervate a portion of gluteus maximus if the dissection is carried too far proximally. Dissection is carried along the posterolateral aspect of the femur while internally rotating the leg. The capsule is opened at approximately the 1-o’clock position on the left hip, is dislocated, and any remnant femoral head is removed. The piriformis cannot be counted on as a landmark for dissection. If dislocation seems difficult, the femoral neck is cut in situ to avoid causing either a femoral or acetabular fracture.
Heterotopic ossification can block exposure and may need to be removed before the hip is dislocated. Especially after prior acetabular fracture surgery, the sciatic nerve can be encased in heterotopic bone. If the patient has preoperative nerve symptoms, this bone is removed, which can be a tedious procedure. In cases of significant limb length discrepancy or if the nerve is thought to be tethered by scar, the nerve is also dissected out. After dislocating the hip, the head is removed and saved for possible bone graft. If suspicion exists for infection, tissue is sent for frozen section, and routine cultures are done regardless.
Step 2: Exposure and Preparation of the Acetabulum
An anterior Hohmann retractor with a double bend is very useful for retracting the femur anteriorly. This retractor is placed on the anterior wall and the anterior and inferior capsule are excised to facilitate exposure. The exposure of the acetabulum can be extended by subperiosteally dissecting along the anterior and superior acetabulum and by taking down a portion of the gluteus maximus tendon.
Acetabular implants are removed if they impede implant placement, if they are loose, or if there is a suspicion for infection. These plates and screws are almost always completely covered with bone and must be dissected out with an osteotome and sometimes fluoroscopy is helpful. If the implants are left in place, care must be taken not to allow contact with implants that would misdirect the reamer ( Fig. 5 ). Removing the most distal screws in a posterior wall plate that extends down to the ischium places the sciatic nerve at considerable risk, and for this reason, the authors try not to remove these plates. On occasion, the authors have used a metal-cutting burr to remove just the portion of the plate blocking exposure or implant placement. Although proximal femoral hardware is usually removed, previous acetabular hardware is frequently left in place if it does not interfere with surgery. The rate of hardware interference has been reported to be from 39% to 81%.
Care must also be exercised about using local landmarks to judge anteversion of the cup when reaming the acetabulum because the posterior wall is frequently deficient due to the prior injury or can become deficient during hardware removal. Usually the most inferior aspect of the posterior wall is preserved and can help with alignment. Fluoroscopy can be useful for obtaining the correct abduction angle. Reamers can also be misdirected by the sclerotic bone that occurs in prior fracture sites.
Cementless acetabular components have superior results and are routinely used. Contained acetabular deficiencies are routinely filled with morselized autograft. Noncontained defects are managed with jumbo cups and metal augments because of the inferior results with structural bone graft. The authors carefully assess for pelvic discontinuity because this must be stabilized at the time of cup placement.
Step 3: Femoral Exposure and Preparation
Femoral preparation after acetabular fracture is usually routine. However, exposure can be more difficult because of stiffness and scar formation. The resection of this scar to enable exposure conversely can result in excessive instability and the natural tendency to overlengthen the extremity. Careful attention to internal landmarks, clinical measurements, and fluoroscopy can help with this. Surgical navigation is also an option.
Surgical procedure: after prior proximal femoral open reduction and internal fixation
The initial exposure is complicated by prior fixation hardware and deformity. Appropriate removal equipment including trephines, easy-outs, and metal-cutting burrs need to be available. More difficulty with implant extraction and abductor problems have been reported with cephalomedullary nails than with sliding screw devices or cannulated screws. Care must be taken not to apply excessive torque on the leg to avoid femoral fracture, and consideration should be given to leaving the hardware in place until the hip is dislocated. Exposure can be aided by using the trochanter as a digastric sliding osteotomy leaving the abductors and the vastus lateralis attached.
If the choice is made to proceed with hemiarthroplasty, one then proceeds to femoral exposure and preparation. For THA, reaming of the acetabulum should be undertaken with care because the bone is usually softer than in cases of arthritis and excessive reaming is easily possible.
Most of the literature describes the use of cemented components in these cases, but good results have also been reported with press-fit diaphyseal engaging stems and with the S-ROM stem. Usually, the authors prefer to use a modular stem with diaphyseal fixation in patients with adequate bone stock. If bone quality is good and there is not much deformity, a proximal fit stem may be used ( Fig. 6 ). If a cemented stem is used, frequently a calcar replacing component and a long stem is needed. Holes from prior fixation need to be plugged before cementing, which can easily be done with screws that have been cut with a bolt cutter. If a noncemented stem is used the prior screw holes should be bypassed to avoid a stress riser and a prophylactic cable may be needed. The trochanter is then wired or cabled, but trochanteric fixation problems are common ( Fig. 7 ). If the initial fixation device is infected, the case may be managed effectively with a two-stage exchange ( Fig. 8 ).
Bercik reported a significantly higher use of diaphyseal fitting implants in patients previously treated with cephalomedullary nails compared to screw and side plate constructs, suggesting that these nails disrupt more proximal metaphyseal bone stock preventing the use of primary metaphyseal press-fit stems. When comparing cannulated screws with screw and side plate constructs for previous femoral neck fractures, Winemaker found no significant difference in blood loss or surgical time. Dehaan also found significantly less operating room (OR) time, implant modularity, and intraoperative transfusions in patients previously treated with cannulated screws compared with those treated either with sliding hip screws or cephalomedullary nails. The sliding hip screw group also trended toward less blood loss, OR time, and implant modularity compared with the nail group, although this did not reach significance. Pui reported a higher complication rate with arthroplasty after cephalomedullary nails than with sliding hip screws including fractures, dislocations, abductor tendon dysfunction, HO, nerve injury, and aseptic loosening.
Previous fracture type also affects intraoperative difficulty in conversion hip arthroplasty. Mortazavi reported a significant difference in the incidence of revision stem use in patients with previous intertrochanteric fractures compared with patients with previous femoral neck fractures. There was also a significantly increased rate of trochanteric osteotomy during surgery for previous intertrochanteric fractures, as well as longer operative time, greater blood loss, and higher transfusion rate. Dehaan found significantly less implant modularity, operative time, and blood loss in previous femoral neck fractures than in peritrochanteric fractures.
Intraoperative fracture is also a concern in these cases. Winemaker reported a higher rate of major (greater trochanter or femoral shaft) fracture complications in the conversion THA group when compared with a matched cohort of patients who underwent primary THA. Dehaan reported an 8.7% rate of intraoperative fracture, all treated successfully with claw plates or cerclage wiring. Zhang reported a 37% greater trochanteric intraoperative fracture rate, all except one successfully treated with claw plates.
Hip balancing can be especially tricky in these cases, and the hip is likely to have more laxity at the correct length than is typical in arthritis cases. Care should be taken to preserve as much capsule as possible. Larger heads, capsular repair, and anterior approaches reduce the likelihood of dislocation.
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