The National Health Insurance Research Database of Taiwan documents more than 100 000 hip fracture diagnoses that have caused more than 2000 in-hospital mortalities every year. Along with the trend of rapid population aging, standard management for hip fractures is a prominent theme and represents a challenge for orthopaedic surgeons. [7-8]
For displaced FNFs, HA is the standard treatment. However, one study reported that the rate of THR use as a primary treatment option significantly increased from 0.7% to 7.7% between 1999 and 2011. Younger patients are being treated with THRs due to their superior mobility and range of joint motion. [9-10] Clinical research has also shown that THR is superior to HA. For example, Ravi reported that THR is associated with lower revision surgery rates and significantly reduces the total costs of hospitalisation. Nevertheless, Sonaje et al stated that HA yielded superior functional outcomes and cost-effectiveness to THR. Wang et al also reported lower proportional hazard values for reoperation in patients treated with HA compared with those treated with a THR. [2-6] Although clinical results are controversial, the surgical procedure of HA has a much shorter duration, results in less tissue damage and exposure, reduces blood loss, improves primary stability, and reduces dislocation and complication rates compared with THR. Moreover, catastrophic metallosis and osteolysis are rarely observed in hemiarthroplasty. These advantages of HA ostensibly make it a superior treatment for older adults with various underlying comorbidities. [1,5]
Some concerns in relation to HA have been discussed in other studies: The reoperation rate for failed HA is reportedly as high as 24%, and the problem of acetabular wear has been noted as the primary cause of HA failure. [11-15] These concerns might provide additional motivation for the recommendation of primary THR for FNF displacement. However, in the present study, the HA failure rate and the THR conversion rate were 2.19% and 1.68%, respectively. In this study, the reasons for the failure of HA were acetabular wear (30.3%), femoral stem subsidence (24.2%), periprosthetic fracture (22.2%), infection (16.2%), and recurrent dislocation (7.1%). The prevalence of acetabular wear, femoral stem subsidence, and periprosthetic fracture were similar within the first 6 months after primary HA according to a multinomial logistic regression analysis. The main cause of early failure was periprosthetic fracture, but the cause of failure became evenly distributed for all 5 groups as time elapsed, and the rates of acetabular wear gradually increased in patients followed up for more than 3 years. A significant difference was demonstrated using a statistical analysis (P < .001***). The aggressive prevention of postoperative trauma is ostensibly more critical than is long-term acetabular wear.
No significant difference was noted in the comparison among the groups for the 5 HA failure types in terms of age, sex, BMI index, ASA classification, prosthesis use, fixation technique, surgical approach, and femoral cup size. The risk factor of HA failure was not identified. Peter et al found that higher ASA scores and BMI indexes (> 40) are strong predictors of revision THR requirement, but similar results were not obtained in our data analysis. Further studies are required to determine the major predictors of HA failure. [16]
The risk of periprosthetic fractures when using cemented or cementless stems are currently discussed. Olof GS et al stated cementless femoral stems are not recommended for the treatment of FNFs in geriatrics high number of due to late-occurring periprosthetic fractures. [17] However, James K et al reported periprosthetic fractures occur equally in cemented and cementless stems under the Vancouver classification. [18] The use of cemented or cementless stems for FNFs remains another controversial issue. From the multinomial logistic regression analysis of this study, the odds ratio of risk of periprosthetic fracture is 2.155 in the cementless group comparing to the cemented group (after adjustment of age and gender), but no significance difference (P = 0.282, CI = 0.532-8.736) is noted. The result of analysis is presented in Table 5. Further studies are needed for to evaluate the fixation technique of femoral stem in this geriatric population.
This study has limitations. First, it was a single-centre retrospective cohort study. Second, surgeries were performed by different surgeons and using different surgical approaches, fixation methods, and prosthesis systems. More comprehensive research and randomised control studies are required to elucidate these results.