In this retrospective study we evaluated the early clinical and radiographic outcomes for the application of cementless, bone conserving and fully hydroxyapatite coated revision stem in primary hemi-arthroplasty for unstable intertrochanteric fractures. The treatment outcomes at average 23-month-follow-up were encouraging. Clinically, patients gained immediate pain relief with early mobilization and prompt return to pre-fracture activity levels with an acceptable mortality rate. Radiographically, stem stability and implant bone ingrowth were achieved at the final follow-up without evident subsidence of femoral stem. Taken together, the results of the current study demonstrated that the current stem played an important role in the treatment of unstable intertrochanteric fractures, especially in senile patients with osteoporosis.
Primary joint arthroplasty acquired arising attention in the treatment of unstable intertrochanteric fractures in elderly patients with osteoporosis. Compared to internal fixation, concerns of joint arthroplasty persisted in prolonged surgical time and increased intra-operative blood loss, which could be lethal to geriatric patients with co-morbidities(2). However, in the present study, the average surgery time could be limited to (74.2 ± 12.1) min, which is shorter than the time reported in the literature for joint arthroplasty(7, 8), and was comparable with the time consumed of an internal fixation procedure for complicated intertrochanteric fractures(18). Additionally, a recent meta-analysis indicated that there was no significant difference between the hip replacement and intramedullary nail groups in terms of length of surgery(18). Although many investigators reported increased intra-operative blood loss in joint arthroplasty compared to intramedullary nail fixation, the rational application of tranexamic acid contributed to the limited blood loss in the present study. The average intra-operative blood loss was (200.1 ± 70.2) ml and the average decrease of Hb was (11.1 ± 6.0) g/L, with only 3 (9.7%, 3/31) patients transfused postoperatively. Although recent meta-analysis reported a statistically increased intra-operative blood loss in hemi-arthroplasty, the authors admitted that the results possessed obvious heterogeneity and the difference might be derived from different devices and levels of expertise of surgeons(18). With minimal invasive posterolateral approach, simplistic techniques for stem implantation and coordination of the MDT group, the effects brought by the operation and anesthesia could be minimized in the present study.
The arthroplasty could shorten the time to immobilize and allowed the patients to full weight bearing as soon as possible postoperatively, which had a notable effect on reducing mortality in hip fractures and preventing complications resulted from long-term bedridden(18, 19). Haentjens et al. found a higher incidence of pneumonia and pressure sores with internal fixation due to restricting early weight-bear mobilization(20). While Iosifidis et al reported that early walking ability after hip fracture of elderly patients was the most significant predictive factor in their long-term survival study with 230 patients(21). In the present study, patients were approved to mobilize one day after the surgery with weight-bearing as tolerated. The rapid pain relief and early stabilization of the joint dramatically simplified the postoperative nursery process and enhanced the rehabilitation progression. Significantly improved VAS and HHS with few incidences of postoperative complications were observed during the hospital-stay, while nearly 70% of the patients returned to their pre-injury activity level at the final follow-up. Additionally, the mortality rate was as low as 3.2% (1/31) during the23 months follow-up, which was much lower than the rate reported in the previous literature. Indeed, these superior results might be attributed to the limited duration of our observation and the small number of patients involved. Nevertheless, we could also postulate that the results were related to the early mobilization and prompt return to pre-fracture activity level introduced by the peri-operative MDT caring protocol.
It was reported that the failure of osteosynthesis or re-operation rate of internal fixation could range from 6–32% for elderly patients with fracture instability, comminution, and osteoporosis, which could exhaust considerable medical sources(6). However, successful bony in-growth was achieved in all patients with no evident implant loosening or subsidence in the present study. The revision stem used in the current study was designed to fill the meta-diaphyseal junction and could obtain long-term biologic fixation with proximal bone loss(22). The extensive hydroxyapatite coating, which was proven to increase biological fixation and allows for even stress distribution and good long-term survival, could also enhance stability via fixation through the bone-hydroxyapatite interface(12, 13). Additionally, guaranteed initial stability and early weight-bearing protocol would also augment osteointegration of the fracture(23). Although long-term follow up might witness a higher rate of implant loosening or revision, the clinical relevance could be debilitated due to lower activity level and limited life expectancy in the elderly population.
The application of the current stem provided a less aggressive but more simplified option in treatment of unstable intertrochanteric fractures in the senile osteoporotic population. A typical revision stem enabled the surgeon to engage the diaphysis to obtain stability distally(24). However, these conventional revision stems require aggressive reaming out to the host cortical bone to properly size the femoral component and prevent subsidence, which could cause frontal thigh pain and proximal stress shielding in 10–24% of cases(11, 25). However, no complaint of thigh pain was observed during the follow-up in the current study. The more proximal press-fitting at the metaphyseal junction of the femoral stem may deliver a more friendly bone loading and stress distribution. Furthermore, the proprietary slots quadrants incorporated in the distal portion of the stem were designed to provide adaptability to the natural curve of the femur. Additionally, in the absence of the diaphyseal reaming, which was reported to be associated with high rate of peri-operative femoral fracture(11), the iatrogenic bone loss could be minimized. No iatrogenic fracture was observed intra-operatively and no peri-prosthetic fracture was noted till the latest follow-up.
The current study is not without limitations. It was a small and short retrospective observation, and the influence of subsidence and potential loosening of the implant requires assessment over a longer period. However, a long-term follow-up study is barely possible and has little clinical relevance in elderly patients, who have a short life expectancy and limited activity during their life. The absence of a control group would inevitably compromise the interpretation of the current results. The patient series involved in the presented study was highly selective, each patient was assessed by a group of MDT professionals to receive a primary hemi-arthroplasty instead of an internal fixation procedure, hence a comparison group could not be recruited.