Total Hip Replacement: Hybrid versus Uncemented: Which Is Better?

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Chapter 83 Total Hip Replacement: Hybrid versus Uncemented: Which Is Better?

KHALED. SALEH, MD, MSc, FRCSC, FACS, MARK. MCCARTHY, MSI, WILLIAM. MIHALKO, MD, PhD, QUANJUN. QUI, MD, MS, THOMAS E. BROWN, MD

Total hip replacement (THR) is one of the most common procedures performed in orthopedic surgery. With an ever-aging population and increasing levels of obesity, arthritic joints are becoming more prevalent. Furthermore, arthroplasty is being performed in younger and younger patients. Although THR results in substantial improvement in quality of life, it is not without intraoperative and postoperative risks, including fat embolism, deep venous thrombosis (DVT), pulmonary embolism, and ultimately failed prosthesis, necessitating another, more significant revision surgery. This chapter examines the decision to cement the femoral component.

Surgical technique is paramount to a successful THR outcome. Currently, much research is being dedicated to evaluate the potential merits and downfalls of minimally invasive surgery (MIS). With regards to total hip arthroplasty, this option remains in its infancy of evaluation. With consumer interest in this cosmetically pleasing, smaller scar, further studies are warranted to ensure minimally invasive THR is a safe and reproducible surgery that parallels the traditional approach and its historically sound results.

The first issue is the risk of intraoperative fat emboli. Fat emboli presents a potential intraoperative adverse event, including the rare but critical bone cement implantation syndrome (BCIS), which leads to death in 0.6% to 1% of patients.¹ BCIS is characterized by hypoxemia, hypotension, cardiac arrhythmias, and cardiac arrest in any or all combinations. Transesophageal echocardiography (TEE) has been used in many studies to evaluate the size and magnitude of embolic cascade during the reaming of the femoral canal. Here, we compare different techniques in hip arthroplasty and show examples of measures taken to reduce the risk for complications from fat emboli in cemented and uncemented arthroplasty.

In one study, the incidence of bone marrow and fat emboli among cemented and uncemented THR was similar ² (Level of Evidence II). Here, 50 consecutive bilateral hip replacements and 106 unilateral hip replacements were enrolled in this study, for a total of 206 hip arthroplasties. One hundred of the hips were treated with cemented stems, whereas 106 of the hips were replaced with uncemented stems. Arterial and right atrial blood samples were obtained before implantation, at 1-, 3-, 4-, and 10-minute intervals after implantation, and at 24 and 48 hours after the surgery. This study found no difference between the prevalence of fat embolism in cemented and uncemented stems, regardless of patients receiving bilateral or unilateral arthroplasties.

Christie and colleagues ³ found that cemented compared with uncemented hemiarthroplasty in the treatment of femoral neck fractures caused greater and more prolonged embolic cascades (Level II). A subsequent study evaluated minimal versus thorough lavage of the femoral canal and found a statistically significant reduction in duration of the embolic responses and number of large emboli, together with less pulmonary function disturbance⁴ (Level II). Although these studies were not done in the context of hip arthroplasty for arthritic joints, it speaks to the importance of thorough femoral canal lavage before cementation.

A modified cementing technique using vacuum drainage into the proximal femur has been successful in reducing intramedullary pressure and the incidence of embolism ⁵ (Level II). Koessler and coworkers⁵ studied the effects of placing vacuum drainage in the proximal femur to reduce the increase in intramedullary pressure during prosthesis insertion. To perform this study, 2 groups of 120 patients were randomized. One group received a total hip arthroplasty using a conventional cementing technique, and the other group used the modified technique described earlier. Perioperative monitoring of embolic events was done by continuous TEE, hemodynamic monitoring, and blood gas analysis. The results in this study show that 93.3% of patients receiving the conventional cementation experienced embolism contrasted with 13.3% occurrence rate in patients undergoing total hip arthroplasty using the modified technique (P < 0.05). Intraoperative shunt values increased from 8.2% to 10.3% during femoral component insertion in the conventional cementation group (P < 0.05). No significant changes were found during femoral stem insertion in the modified group. No patients in either group sustained fat embolism syndrome. These results show that the embolic events seen under TEE can lead to increased pulmonary shunt values during THR, most notably in those patients with systemic disease. The modified technique, designed to reduce increases in intramedullary pressure, reduced the incidence of embolism.

Pitto and investigators ⁶ performed a similar study, utilizing a bone-vacuum technique in the experimental group (Level II). Here, 130 patients were randomized to receive a standard cemented hip without the use of a bone vacuum or to have the arthroplasty performed with the use of a bone vacuum (65 patients in each study). This study examined the incidence of embolic events via TEE as well. However, serial duplex ultrasonography was used to assess the occurrence of DVT in each of the groups. This was done the day before surgery and on postoperative days 4, 14, and 45. The control, standard cementation group had significantly more embolic particles and masses (in 59 patients, or 91%) versus the group that underwent femoral component implantation with the concurrent use of a bone vacuum (10 patients, or 15%). Furthermore, ultrasonography on postoperative day 4 found DVT in 12 of the patients in the control group (18%) compared with a DVT rate of 3% (2 patients) on postoperative day 4 in the experimental group (P < 0.05).

Pitto and investigators ⁷

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