Feature Article

Hip Hemiarthroplasty After Displaced Femoral Neck Fracture: A Survivorship Analysis

Thomas Tanous, MD; Kelly W. Stephenson, MD; Michael J. Grecula, MD

  • Orthopedics
  • June 2010 - Volume 33 · Issue 6: 385
  • DOI: 10.3928/01477447-20100429-08
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Abstract

The standard of care for displaced femoral neck fractures is not clear. We reviewed all patients 65 years or older with displaced femoral neck fracture who underwent hip hemiarthroplasty at our institution between 1997 and 2006. Women accounted for 70% of the patients. Mean patient age was 78 years, and most of the patients were community ambulators.

Complete operative information was available for 226 (79%) of 285 patients. Follow-up was available for 126 patients (mean, 15.8 months; range, 1-97 months). Total mortality rate was 58%. Mean University of California, Los Angeles (UCLA) scores were 8.3 for pain, 6.7 for walking, 5.6 for function, and 3.5 for activity. Two patients had acetabular wear on radiography, but symptoms were not severe enough to warrant revision. Three patients (1.3%) underwent revision, 1 with acetabular wear and 2 for infection.

Despite the limited follow-up, the rate of conversion to total hip arthroplasty (THA) was low. Longer, prospective studies are needed to delineate which patients will benefit from THA.

Displaced femoral neck fractures in the elderly are a frequent presentation to orthopedic surgeons. In 1996, the US Department of Health and Human Services reported approximately 340,000 hip fractures, most occurring in women older than 65 years. With the increase in the elderly population, the estimated number of hip fractures worldwide is expected to jump from 1.7 million in 1990 to 6.3 million by 2050.1 There is growing concern among orthopedic surgeons regarding the morbidity and mortality associated with such injuries.

Despite multiple studies—including prospective, randomized, controlled trials—there is no clear standard of care in the treatment of displaced femoral neck fractures.2-6 Options include internal fixation, hemiarthroplasty (unipolar, bipolar), and total hip arthroplasty (THA). Nonoperative treatment is generally reserved for nonambulatory, bedridden patients without pain. There are advocates for each treatment option.

Studies have evaluated internal fixation vs hemiarthroplasty. A recent meta-analysis of 106 published reports found an approximately threefold increase in reoperation if internal fixation was performed compared with hemiarthroplasty for displaced femoral neck fracture in patients older than 65 years.7 In another study, hemiarthroplasty patients had less pain, were more satisfied with the result of the operation, and had better quality of life (EQ-5D) scores at 4 months postoperatively.8

Researchers have looked at femoral fixation options as well. Many studies have shown equivalent results with unipolar, bipolar, cemented, and uncemented hemiarthroplasties.9-12 Despite the increased success of hemiarthroplasty over internal fixation, concerns exist. Some patients who undergo hemiarthroplasty experience discomfort and compromised function with time, commonly associated with degeneration of the articulating acetabular cartilage.13-15 Rates of reported acetabular erosion range from 0% to 36%.16-18 Macaulay et al19 conducted a prospective, randomized, controlled trial of THA vs hemiarthroplasty in displaced femoral neck fractures. They found that at 24 months, THA patients had significantly less pain according to the Medical Outcomes Study SF-36, superior Western Ontario and McMaster Universities Arthritis Index (WOMAC) function scores, and no greater incidence of complications than did hemiarthroplasty patients. Other studies have agreed that THA appears to have lower short-term morbidity and lower 2-year costs compared with other treatment options.2,5,20-22

Literature on the conversion of a hemiarthroplasty to a THA23-28 has been described as “fraught with high complication and loosening rates.”23 Sierra and Cabanela23 reported that “the seemingly easy operation of implanting an acetabular cup to convert a hemi to a THA is an uncertain procedure and the threshold for replacing the stem should be low.” In one study, the median time from conversion procedure to the next revision was 3.6 years in the group with stem exchange and only 6 months in the group with retention of the femoral stem.29 Dislocation was the most common mechanism of failure in the group as a whole.

Materials and Methods

We retrospectively reviewed all patients 65 years or older with displaced femoral neck fracture who underwent hip hemiarthroplasty at our institution between 1997 and 2005. The database of 1 of the senior surgeons (M.J.G.) and the institution’s database were used to screen for patients. The International Classification of Diseases version 9 (ICD-9) code for femoral neck fracture (820.0) and Current Procedural Terminology (CPT) code for hip hemiarthroplasty (27125) were used to identify patients. Data were obtained from hospital charts, clinic charts, operative reports, and the Social Security Death Index.

Two hundred eighty-five patients were identified. Of those, 226 (79%) had complete operative information available. Seventy percent of patients were women. Median patient age was 78 years, and most patients were community ambulators before injury (Table 1). Mean time to surgery was 4.5 days. Thirteen surgeons (K.W.S., M.J.G.) performed the operations, either through a posterolateral or anterolateral approach. Nearly all patients underwent a cemented, unipolar hemiarthroplasty. All patients received postoperative prophylactic therapy against deep vein thrombosis.

Table 1: Patient Demographics

Institutional review board approval was obtained. Age, sex, leg affected, previous ambulatory level, fracture type, time to surgery, type of prosthesis, operating surgeon, complications, additional surgeries performed, duration of follow-up, and if-deceased data were collected. Using information from the latest follow-up visit, University of California, Los Angeles (UCLA) 10-point pain, walking, function, and activity scores30 were determined. Patients with incomplete information were excluded. Endpoints of the study were revision surgery or death from any cause.

Results

Follow-up

Of the 226 patients with complete operative data, 126 (56%) had follow-up after discharge from the hospital. Ninety-nine (44%) did not have follow-up after discharge or had died. Mean follow-up was 15.8 months (range, 1-97 months). The total mortality rate at the time of the study was 58%. The 1-, 2-, 4-, and 5-year mortality rates are listed in Table 2, as are the UCLA scores calculated from last follow-up. Two patients were found to have acetabular wear on radiography, but symptoms were not severe enough to warrant revision.

Table 2: Follow-up Data


Complications

Three patients (1.3%) underwent revision, 2 for infection requiring a 2-stage revision and 1 for pain with presumed acetabular wear converted to a THA at an outside institution. The last patient has subsequently followed up with continuing pain after conversion. One other patient (bedbound in a nursing home) was found to have a protrusion on radiography but did not undergo revision. There were 4 superficial wound infections, all in patients who had received anticoagulation therapy (warfarin) prior to injury. Four patients sustained intraoperative fractures (1 greater trochanter, 2 calcar fractures, and 1 femoral shaft fracture). One patient went on to chronic dislocation. That patient’s surgery had been performed from a posterior approach; since then, our institution has converted to the anterolateral approach for hip hemiarthroplasties.

Discussion

Most current debates on treatment for displaced femoral neck fractures focus on whether to resurface the acetabulum to prevent complications from acetabular wear. While several high-quality studies compare hemiarthroplasty with THA, the question remains whether acetabular wear is a widespread problem.

The 1-year mortality rate in our study was 17%, which is similar to that previously reported.31 In addition, as many as one-half of all patients die within 5 years.32 The onset of acetabular wear as described in the literature is approximately 5 years after implantation23 and in as many as 36% of patients.16-18 Nearly one-half of patients are then likely to have died prior to the need for revision. The indications stated for revision in these studies are not solely acetabular wear with thigh pain, loosening, infection, and periprosthetic fractures included.

Haidukewych et al11 found a significant mortality rate increase at 1, 2, and 5 years in patients with femoral neck fracture compared with expected rates for a general population. To our knowledge, no studies have shown improved patient survival in those undergoing THA vs hemiarthroplasty. In fact, Macaulay et al19 found a 35% overall mortality at a mean follow-up of 34 months (range, 29-42 months), which is a similar rate to internal fixation or hemiarthroplasty reported in the literature. It was shown that this patient population has a 2.4 times greater likelihood of death for each additional comorbid condition when compared with individuals with no comorbid conditions.19

Total hip arthroplasty, despite providing excellent pain relief and improving ambulatory capacity and function scores, has a worrisome dislocation rate. Reported rates of dislocation vary from 0% to 36%.33 Our study included 1 patient with a dislocation who had a posterolateral approach for hemiarthroplasty. Many proponents point to the small-diameter head size used in some studies as a factor in the increased rates of dislocation, with rates approaching those of THA for osteoarthritis when using the now more commonplace larger-diameter bearings.

One concern is that many previous community ambulators in our study required assistive devices despite having good pain relief. This appears to be a multifaceted problem having physical and psychological causes. Many patients feel more comfortable using these devices in light of their previous fall.

The average time from injury to surgery was 4.5 days. Many patients had significant comorbidities that required workup (eg, stress tests and pulmonary function tests) before being cleared for surgery.

Postoperative follow-up was lower than in other studies in the literature. This is partially because our institution is located in a resort area, with many people returning home for follow-up. Moreover, nursing home residents have difficulty commuting back and forth for their follow-up. Many patients were discharged at 6 weeks to 3 months with as-needed follow-up, which limited the ability to capture patients with complications.

Nearly all patients with follow-up are pain free. In those with continued pain, it is occasional, and trochanteric bursitis is the usual cause. Only 3 patients in the study had acetabular wear radiographically. Two of them did not have sufficient pain for conversion to THA to be considered. The lone patient with (presumed) acetabular wear and revision (done at an outside institution) returned after conversion and was being worked up for infection at last follow-up because of continued pain.

The major limitations of this study are that it is retrospective and lacks follow-up for nearly one-half of the patients. Despite the limited follow-up, the rate of conversion to THA is low. While pain relief is predictable, preoperative functional level is not always attained. This appears to multifactorial. In the future, longer, prospective studies with follow-up are needed to delineate which patients will benefit from THA rather than hemiarthroplasty.

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Authors

Drs Tanous and Stephenson are from the Department of Orthopedic Surgery and Rehabilitation, The University of Texas Medical Branch, Galveston, and Dr Grecula is from the Department of Orthopedic Surgery, The University of Texas Medical School, Houston, Texas.

Drs Tanous, Stephenson, and Grecula have no relevant financial relationships to disclose.

The authors thank Suzanne Simpson for assistance in the preparation of the manuscript.

Correspondence should be addressed to: Kelly W. Stephenson, MD, Department of Orthopedic Surgery and Rehabilitation, The University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555-0165 (kestephe@utmb.edu).

doi: 10.3928/01477447-20100429-08

doi: 10.3928/01477447-20100429-08

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