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Fig. 2 A, Radiograph showing Garden III fracture with varus angulation. B, Following reduction on a fracture table, the deformity is corrected and pinning is performed. Reproduced from Gardner MJ, Lorich DG, Lane JM: Osteoporotic femoral neck fractures: Management and current controversies. Instr Course Lect 2004;53:427-439.

AAOS Now

Published 5/1/2010
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Terry Stanton

Pearls and pitfalls on fixing hip fractures

Symposium addresses strategies for management

Hip fractures are a worldwide problem, and their number is expected to grow “exponentially” over the next 50 years, said Kenneth J. Koval, MD, in his opening presentation in a symposium on this injury at the Hip Society’s Specialty Day meeting in New Orleans.

Noting that the number of individuals aged 65 or older worldwide will rise from 323 million in 1990 to an estimated 1.6 billion by 2050, Dr. Koval said that the estimated number of hip fractures will leap from 1.7 million to 6.3 million over the same period. The trends are not all negative, however; although the totals are swelling, it appears that incidence is decreasing. One report found that after rising from 1986 to 1995, the age-adjusted incidence of hip fractures declined from 1995 to 2005. (The authors speculated that increased use of bisphosphonates may have been a factor.)

“The burden of hip fracture is large,” Dr. Koval said, and will consume a growing portion of economic resources. “In an era of cost-consciousness and fiscal limitations, the economic costs of hip fracture will have a staggering effect.” The annual cost of treating osteoporosis—$13.8 billion—is similar to that of treating cardiovascular disease and asthma.

In terms of medical burden, hip fracture is one of the most important causes of morbidity and mortality in older persons and “can rob the elderly of their independence and has wide psychosocial consequences,” he said.

Hip fractures constitute 45 percent of all fractures among Medicare enrollees (Fig. 1). One out of four hip fractures results in long-term nursing home care, Dr. Koval noted. Even a year after the fracture, about half of injured patients are unable to walk without assistance, only 40 percent are able to perform all physical activities of daily living, and 80 percent are unable to carry out at least one independent activity of daily living. Mortality rates for the injury are 7 percent at 1 month, 13 percent at 3 months, and 24 percent at 1 year. A 5-year prospective cohort study found that in women, fracture of the proximal femur had an age-standardized mortality ratio of 2.2, compared with 1.7 for vertebral fractures and 1.9 for other major fractures.

What to do with displaced femoral neck fractures
Recent findings have suggested that the role and efficacy of internal fixation (Fig. 2), hemiarthroplasty, and total hip arthroplasty (THA) in the management of displaced femoral neck fracture need to be re-evaluated, said Jay R. Lieberman, MD.

“In this area, we have good evidence to help us make decisions,” he said. He posed the following three questions to ask about a hip fracture involving the femoral neck:

  • Can it be treated with internal fixation or an arthroplasty?
  • If it’s going to be treated with an arthroplasty, will it be a total or a hemi?
  • If it is a hemiarthroplasty, will it be a unipolar or a bipolar?

“Our management goals are to restore function to the patient,” Dr. Lieberman said. “We want to do one operation for the lifetime of the patient, if possible.”

In reviewing the three main management options, Dr. Lieberman said that internal fixation has the perceived advantages of a shorter operation, less bleeding, and decreased mortality. For THA, patient selection is critical. Definitive indications include osteoarthritis, inflammatory arthritis, and failed internal fixation or hemiarthroplasty. Interest in THA has increased with the advent of large femoral heads and improved results.

THA is, however, a longer procedure, with increased risk of complications. Although dislocations are less of an issue when larger heads are used, small female patients may not be able to receive larger heads. Finally, cost is also an issue.

Prospective randomized studies have indicated that THA provides better function and fewer reoperations overall than internal fixation. Data from the Swedish Arthroplasty Register support the safety of THA for the primary management of hip fracture, and a meta-analysis of randomized studies of arthroplasty versus internal fixation showed fewer operations and reoperations with THA and no significant differences in mortality at 30 days or 1 year.

For the healthy, active patient between the age of 70 and 90 (the age group studied in the randomized trials), a total hip replacement “would be preferred over internal fixation,” said Dr. Lieberman. “But we need more data on patients between 60 and 70 years of age.”

Two randomized trials have compared outcomes after THA or hemiarthroplasty. In one study, patients who received a THA showed better overall function than those who had a unipolar hemiarthroplasty procedure. Although the dislocation rate was slightly higher for the THA group, the difference was not significant.

The other study compared THA with bipolar hemiarthroplasty. The THA group demonstrated better Harris hip scores at 4 and 12 months, but no differences were found in health-related quality of life outcomes, dislocations, or mortality.

“To decide between a hemi and a THA,” Dr. Lieberman said, “an accurate assessment of the patient’s mental status and function is needed. A patient who is healthy and an active community ambulator should have a THA.”

The bipolar hemiarthroplasty procedure has a theoretical advantage over the unipolar hemiarthroplasty, he said, because the second articulation may increase range of motion and decrease wear. Randomized trials have found no difference between the two groups with respect to dislocation, revision, mortality, or infection, but the studies tended to be small.

Candidates for hemiarthroplasty include low-demand patients or nursing home residents, those with comorbidities and a history of multiple hospitalizations, and patients who need help with activities of daily living or have a compromised mental status. “I would also consider a hemiarthroplasty in a small patient who cannot accommodate a large femoral head,” Dr. Lieberman said.

He concluded that larger trials are necessary to define the patients who can truly benefit from THA and to establish the superiority of THA in certain patient populations.

Conversion to arthroplasty after failed ORIF
Miguel E. Cabanela, MD,
discussed the following technical considerations when converting failed fixation of femoral neck fractures to THAs:

  • The hip should be dislocated prior to hardware removal to reduce the chance of producing an additional fracture.
  • Because acetabular bone is soft, overreaming should be avoided and ancillary fixation in the socket is advisable.
  • After hardware removal, standard total joint arthroplasty can generally proceed.

“I personally prefer cement fixation on the femur because many of these patients have poor bone,” Dr. Cabanela said. “With uncemented fixation, the incidence of intraoperative cracks is higher.”

THA after femoral neck fracture is associated with a high dislocation rate, Dr. Cabenela noted. For this reason, he recommended the use of large prosthetic heads and capsular and soft-tissue repair. An anterior approach would include “a good repair of the gluteus medius,” while a posterior approach would require a complete repair of the external rotators as well as the capsule.

Failed fixation of intertrochanteric fracture can occur for several reasons, including implant cutout, loss of reduction, poor remaining bone, and articular damage, Dr. Cabanela said. Joint arthroplasty is indicated for this situation, and the decision to use a hemi or a total procedure depends on the condition of the acetabular cartilage. If it is adequate, a bipolar arthroplasty may work; if the cartilage is damaged, a THA should be performed.

When converting from open reduction and internal fixation to THA, the joint should be dislocated first, before the hardware is removed. This step can prevent additional fracture related to the weakening of the femur after the hardware is removed.

Because screws may be broken, screw removal sets should be available during surgery. To avoid the effects of a stress riser, screw sites “can be bone-grafted,” he added.

As with femoral neck fracture cases, socket overreaming should be avoided and ancillary screw fixation is advisable. “If the acetabular cartilage is well preserved, then socket replacement might not be necessary, and a hemiarthroplasty might be enough,” said Dr. Cabanela.

Among the femoral issues that arise is bone loss below the standard resection level for a primary THA. Calcar replacement femoral component designs should be available at surgery, and long stems are frequently needed to bypass the stress risers at the previous hardware sites.

The increased bone deformity, callus, and sclerosis along the intertrochanteric region may necessitate the use of special instruments to enter the canal or shape the proximal femur, Dr. Cabanela said. To avoid creating a false passage in the femur or problems with finding the canal, he recommended obtaining an intraoperative radiograph once the trial prosthesis is in place.

“My parting thought is that THA after femoral neck and intertrochanteric fractures is a reliable procedure,” Dr. Cabanela said. “Instability must be prevented, so remember soft-tissue repair and the use of large heads. Complications after intertrochanteric fractures abound, and attention to technical details will help reduce them.”

Disclosure information: Dr. Koval—Biomet, Stryker; Dr. Lieberman—DePuy; Dr. Cabanela—Stryker.

Terry Stanton is senior science writer for AAOS Now. He can be reached at tstanton@aaos.org

Bottom line

  • By 2050, the estimated number of hip fractures may be 6.3 million annually.
  • Internal fixation for displaced femoral neck fractures may result in a shorter operation, less bleeding, and decreased mortality, but studies show that THA may be a better choice for healthy, active patients older than age 70.
  • Hemiarthroplasty may be appropriate for patients who are low-demand, have comorbidities, or need help with activities of daily living.
  • When converting from ORIF to THA, dislocate the joint first, avoid overreaming the socket, use ancillary screw fixation, and obtain an intraoperative radiograph after placing the trial prosthesis.