Subtrochanteric shortening osteotomy recommended for total hip replacement

Harris Hip Score improved significantly and no nerve injuries occurred in 21 patients with DDH.

Issue: February 2006

ORLANDO, Fla. — Canadian investigators reported that performing subtrochanteric femoral shortening osteotomy, using strut grafts to minimize femoral nonunion risk and integrating crosslinked polyethelene, improved implant longevity in patients with developmental dysplasia of the hip.

At an average five-year follow-up (range, two to 11 years), researchers reviewed 23 subtrochanteric femoral shortening osteotomy cases in 21 patients from a cohort of 142 hips treated for developmental dysplasia of the hip (DDH). The average patient age was 48 years and average weight was 69.2 kg.

In total hip replacement (THR) cases, Harris Hip Scores improved from 39 preoperatively for both cemented and cementless implant recipients to 74 for cemented and 73 for cementless implant recipients. Researchers found five complications and no nerve injuries. Preoperatively, 69% of patients demonstrated a severe limp, but this dropped to 25% postoperatively.

Bone Resection [photo]

The average bone resection was 35 mm. Surgeons used the bone overflap as an indication of how much bone to resect, starting with less bone than anticipated and then went through a trial reduction series.

Courtesy of Robert Boune

“Subtrochanteric femoral shortening osteotomy to restore the anatomical hip center is a very desirable way of dealing with these most difficult patients,” Robert Bourne, MD, FRCS(C), at the University of Western Ontario, said at the 22nd Annual Current Concepts in Joint Replacement Winter 2005 Meeting.

Typically, patients with DDH have a hypoplastic acetabulum, poor bone quality, a small femur, increased neck-shaft angle, increased femoral neck anteversion and a posterior greater trochanter.

The basic principle, Bourne said, is to find the “true acetabulum” and place the acetabulum in that location.

Subtrochanteric shortening osteotomy allows surgeons to safely address potential leg-lengthening problems and sciatic nerve injury, Bourne said, adding that they can also use it “to change the position of the greater trochanter from a posterior position to one that is in a more biomechanically sound position.”

In the University of Western Ontario study, “All sockets were placed in the true acetabulum, we used cementless sockets and … the average outside diameter was 44 mm (range, 40 mm to 48 mm),” Bourne said.

On the femur, surgeons used cemented stems in eight cases and cementless in 15, mainly because crosslinked polyethylene was not available. They used a 22-mm head in 21 cases and a 28-mm head in two cases.

The surgical technique

Before performing the subtrochanteric osteotomy, surgeons reamed the femur and prepared the sleeve. During the operation, they flipped the proximal femur fragment as in a trochanteric slide for “excellent vision of the acetabulum,” Bourne said.

The average bone resection was 35 mm (range, 20 mm to 70 mm). Bourne said the bone overflap gives surgeons an idea of how much bone to resect.

“Usually we start with less than we might anticipate and then do a series of trial reductions,” he said. “It’s a lot easier to go back and resect a little bit more bone than to add more at the end.”

Once surgeons were satisfied with the final construct, they introduced the final components, using strut grafts in nine patients in anticipation of possible healing problems.

Results and complications

With the Harris Hip Scores improving from 39 for both cemented and cementless at preop to 74 for cemented and 73 for cementless, “there was marked improvement from preop to postop, but … the scores are a good 10 to 15 points lower than you might expect with a primary total hip replacement,” Bourne said.

The five complications included two nonunion osteotomies, one recurrent dislocation, one polyethylene failure and one aseptic loosening, but no nerve injuries.

Although 69% of patients had a severe limp and had a moderate limp preoperatively, only 25% of patients had a severe limp, 35% a moderate limp, 20% a mild limp and 20% demonstrated no limp after surgery.

For more information:

Bourne R. Surgical challenges of the dysplastic hip. #27. Presented at 22nd Annual Current Concepts in Joint Replacement Winter 2005 Meeting. Dec. 14-17, 2005. Orlando, Fla.