Displaced femoral neck fractures typically require surgical management. The aims of such surgical interventions include providing immediate pain relief, restoring functional activity, enhancing the rate of rehabilitation, and preventing complications1). Cemented hip prostheses have been used traditionally in patients with osteoporosis; however, cement-related cardiopulmonary complications have been observed in these patients^2,3,4). Cementless total hip arthroplasty (THA) has been used with increasing frequency in recent years, as this procedure lowers the risk of cement-related cardiopulmonary complications and has the advantages of short operation times and high survival rates^5,6,7,8). The choice of prostheses remains controversial due to the clinical outcomes observed following THA or bipolar hip hemiarthroplasty (BHA)9). As compared to THA, BHA has the advantages of lower probabilities of dislocation, shorter operation times, lower degrees of blood loss, and lower operation costs. However, THA has been associated with functional advantages over BHA1). The aim of the current study was to assess the early clinical and radiological results of cementless hip arthroplasty (HA) for femoral neck fractures in elderly patients with osteoporosis.

Of the 87 included cases, no patients died before discharge, 7 were unable to be followed-up, and 10 (11.5%) died within the first postoperative year. Excluding those patients, 70 cases were followed-up for a minimum of 24 months (mean, 28.4 months; range, 24-37 months). THA was conducted 34 patients, and the remaining 36 patients underwent BHA. The mean age of the 70 evaluated patients was 77.8 years (range, 65-94 years), and the mean postoperative hospital stay was 22.4 days (range, 7-89 days) (Table 1). The mean durations of the operations were 86.8 minutes (range, 80-100 minutes) and 65 minutes (range, 50-105 minutes) for those who underwent THA and BHA, respectively (P<0.05). Changes in perioperative hemoglobin levels were 2.4 mg/dL (0.7-3.7 mg/dL) and 1.4 mg/dL (0.6-2.7 mg/dL) in those who underwent THA and BHA, respectively (P<0.05) (Table 2). The overall change in the functional items of the perioperative HHS scores was 3.6 (0-28), and significantly better results were achieved for those who underwent THA (mean, 2.8; range, 0-9) than for those who underwent BHA (mean, 5.2; range 0-28; P<0.05). At the final follow-up, mean HHS scores reflected better outcomes for those who underwent THA as opposed to BHA (80.4 vs. 61.9, P<0.05). In the ambulatory status analysis, the mean perioperative change for all patients according to the Koval classification grade was 0.8 (0-4). Perioperative changes were 0.7 (0-3) and 1.0 (0-4) in those who underwent THA and BHA, respectively, and no significant difference was detected between the two groups (Table 3).

Radiologic evaluation revealed subsidence of the femoral stem associated with component loosening in one case (1.4%) on the sixth postoperative week. This patient rejected revision surgery and is currently under follow-up with wheelchair ambulation only. Excluding this case, all patients demonstrated bony ingrowth fixation of implants at the final follow-up (Fig. 1).

Intra-operative femoral cracks occurred during femoral stem fixation in 3 cases (3.4%) and were treated with cerclage wire fixation (Fig. 2). Dislocation as a postoperative complication was not observed in any case, and no revision surgeries were conducted. Ectopic bone formation of Brooker grade I was detected in 2 cases. Deep infection was not observed in any case, although other complications, such as pneumonia and deep vein thrombosis, were noted in 10 cases and one case, respectively (Table 4).

Lee et al.8) have previously reported the achievement of satisfactory outcomes from BHA with a cementless femoral stem in patients with femur neck fractures. A survival rate of 98.6% was shown using the same femoral stem without any specific complications in the current study, with the exception of a case (1.4%) of femoral stem loosening. Although cementless arthroplasty has been associated with difficulty in achieving early stability, bone resorption, and other problems as compared to cemented arthroplasty, it remains a commonly applied procedure due to the advantages of short operation times and low rates of cardiovascular complications^17,18,19). The known complications of cementless hip arthroplasty include intraoperative periprosthetic fractures, weakening of the cortical bone due to stress shielding, micromotion of the femoral stem end, and thigh pain^11,20,21). Although intraoperative femoral cracks were noted in 3 cases (3.4%) after femoral stem fixation for early stability in the current study, they were simple cracks associated with stability of the femoral stem and managed with cerclage wire fixation without any complications. However, the problem of increasing stem size was detected in elderly osteoporotic patients in the current study due to the nature of the tapered-wedge stems used to fix the femoral stems.

The controversy surrounding the superiority of either THA or BHA for elderly osteoporotic patients with femoral neck fractures has a long history. Since its introduction in 1974, bipolar arthroplasty has been widely used. However, Langan22) reported that no movement of the acetabular cup was found in 86% of subjects in the first postoperative year after BHA, and wear of the acetabular components occurred due to the increased outer movement and decreased inner movement in the acetabular cup¹⁸,19). As the potential adverse effects of BHA have been addressed, several studies have investigated the advantages of THA over BHA. Recent studies have reported that, despite a higher risk of early dislocation and longer operation times in THA as compared to BHA, there was an insignificant difference in complications between two groups^23,24,25,26). Moreover, several studies have suggested the benefits of THA with respect to HHS and revision rates^23,24,25,26,27). In the current study, changes in the functional items of the perioperative HHS were significantly more favorable in THA patients. Furthermore, the total HHS was significantly better in THA patients postoperatively. To account for between-group differences in compliance and early functioning, changes in the functional items of the pre- and postoperative HHS were compared. The results for patients who underwent THA were significantly better using this approach. Thus, THA may be considered as more beneficial in patients with good compliance.

None of the patients in either group showed postoperative dislocations. This may be attributable to the adoption of surgical procedures using an anterolateral approach, consistent postoperative education for patients, abduction pillow use in the ward, and bed confinement for 3 months, all of which have lowered the incidence of dislocation in the hip.

The current study had several limitations. The answers to questions asked during a 24-month follow-up may be inaccurate in elderly patients with dementia in a retrospective study. Additionally, the complications experienced by patients who were unable to be followed-up were excluded. Furthermore, good compliance and the systemic state of patients may have caused selection errors in the comparison of the two groups. Lastly, meaningful comparisons are difficult due to the relatively small sample size.

The early (24-month) follow-up results of cementless HA for femoral neck fractures in elderly patients with osteoporosis were satisfactory. Although objective comparisons were difficult due to differences in patient selection between the THA and BHA groups, THA showed more favorable results in functional changes in the pre- and postoperative HHS of patients who underwent THA. Routine follow-up is warranted to improve the long-term survival rate of cementless THA, and further studies comparing the long-term outcomes between the two different HAs are essential.

Table 1. Patient Demographics

Table 2. Comparison of Perioperative Parameters

Table 3. Clinical Outcomes after Last Follow-up

Table 4. Postoperative Complications