IMPORTANT POINTS:
- 1
The optimal position of fusion is 5 to 10 degrees of hip adduction, 25 to 30 degrees hip flexion, and 10 degrees external rotation of the hip.
- 2
Patients should not have any degenerative changes of the back, knees, or opposite hip.
- 3
Revision to a total hip arthroplasty may be considered for pain and mobility purposes, but abductor function should be intact to maintain stability.
CLINICAL/SURGICAL PEARLS:
- 1
Use a technique to spare abductor function.
- 2
Evaluate for abductor function before performing a total hip arthroplasty.
- 3
Achieve good skeletal fixation to avoid pseudoarthrosis.
- 4
Carefully evaluate the position of fusion to avoid degenerative changes of the back, knees, or opposite hip.
CLINICAL/SURGICAL PITFALLS:
- 1
Fusion of the joint in the above position is critical to avoid arthritis and pain in the knees, back, and other hip.
- 2
If abductor function is compromised, a patient should not be a candidate for a hip arthroplasty because of the risk of instability or dislocation.
- 3
Counseling patients about expectations is extremely important for successful outcome and satisfaction after the procedure.
INTRODUCTION
Hip arthrodesis was introduced in 1886 in France by Lagrane. Albee was the first in the United States to describe an intraarticular arthrodesis in 1908. Watson-Jones described the transarticular nail arthrodesis in 1939. Brittain popularized an extraarticular arthrodesis with intertrochanteric osteotomy and ischial femoral bone grafting in 1941. Charnley described a central dislocation and internal compression fixation technique in 1953. Another traditional method is a “cobra head” plate described by Schneider in 1966. For more than 50 years, it served as the treatment of choice for a painful hip. After the introduction of conventional hip arthroplasty in the 1960s, arthrodesis has gradually lost favor. This is attributable in part to lack of surgeon enthusiasm and experience as well as patients’ decreasing acceptance of the procedure.
INDICATIONS AND CONTRAINDICATIONS
The optimal candidate for hip arthrodesis is a manual laborer younger than 30 years with isolated hip arthritis ( Fig. 9-1 ). Patients should have no pain in the low back, contralateral hip, or ipsilateral knee. No radiographic evidence of degenerative changes should be present in these areas. These changes are considered absolute contraindications for the procedure. Patients with avascular necrosis of the femoral head should have the contralateral femoral head carefully evaluated by magnetic resonance imaging before arthrodesis is considered. Ipsilateral knee instability also should be considered a contraindication for the procedure. Patients who are taller than 72 inches should be warned they may have difficulty sitting comfortably in cramped spaces. Men older than 50 years and women older than 40 years may be considered more appropriate candidates for total hip arthroplasty.
Patients and their families also should be extensively counseled about long-term results and reasonable expectations for the procedure. The patient must be motivated and want to return to work. Patients often are reassured by speaking to individuals who have undergone the procedure. Patients who are unsure if they will be able to tolerate a hip fusion may try a short 1- to 2-week trial of hip spica cast immobilization preoperatively to see if a fusion would be tolerable.
SURGICAL TECHNIQUE
The goals of hip arthrodesis are to create rigid internal fixation, minimize shortening, provide maximal bony contact to facilitate fusion and, ideally, allow for conversion to total hip arthroplasty in the future. Several methods to achieve these goals have been described. A traditional method is fusion with a cobra-head plate. Arthrodesis with cobra-head plating involves a transverse osteotomy and has been shown to cause considerable abductor dysfunction. The patient is placed in the supine position with a sandbag under the ipsilateral buttock. Both lower extremities are prepped and draped. A mid-lateral incision is made 8 cm above and extended 8 cm distal to the greater trochanter in the interval between the tensor fascia lata and the gluteus maximus. The anterior and posterior borders of the gluteus medius are identified and a trochanteric osteotomy is performed. The surgeon should be careful to avoid the medial femoral circumflex vessels located along the posterior aspect of the superiolateral femoral neck. The joint capsule is incised from its acetabular insertion with an incision toward the anterosuperior femoral head to avoid the circumflex vessels. After this incision, the femoral head is dislocated anteriorly ( Fig. 9-2 ).
A concave reamer is then used to shape the femoral head to fit the acetabulum ( Fig. 9-3 ). If necrotic bone is present, no attempt is made to resect all the necrotic bone because this would lead to excess shortening of the limb. The head is reamed in the normal fashion, and drill holes are placed in the necrotic bone. The acetabulum is reamed to bleeding bone with convex reamers to the same size as the femoral head (see Fig. 9-3 ). Pelvic osteotomies are required if femoral head subluxation is present to provide coverage for the femoral head.
The sandbag is deflated and the limb is placed in 5 to 10 degrees of hip adduction, 25 to 30 degrees hip flexion, and 10 degrees external rotation of the hip. A sterile goniometer can be used to assess the measurements. Steinman pins also can be placed into each anterior superior iliac spine to determine adduction and abduction with the goniometer. Internal and external rotation can be assessed by using the pins and the position of the patella and medial malleoli for comparison. Fluoroscopy also can be used to help obtain these measurements. After an image centered over the pelvis showing the femur and ischial tuberosities is intensified, the angle between the femur and pelvis can be measured.
The cobra-head plate is then contoured to fit the femur. A distal bend is placed in the plate to prevent it from abducting the leg ( Fig. 9-4 ). A 4.5-mm cortical screw is placed through the plate into the ilium. A tensioner is then applied to obtain compression to the femur. The remaining screws are placed through the plate into the femur. The greater trochanteric osteotomy is then repaired over the plate with one to two cancellous screws ( Fig. 9-5 ). Bone autograft from the reaming and allograft may then be applied between the plate, femur, and ilium. In a revision setting for pseudoarthrosis, iliac crest bone graft may be used and secured with a screw from the femoral neck to the anterior ileum.
