Cementless Total Hip Arthroplasty After an Iatrogenic Subtrochanteric Fracture due to Hardware Removal: A Case Report

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Introduction
2][3][4][5] High rates of complications, predominantly periprosthetic fractures, abductor dysfunction, and medical complications, were reported in the largest case series.2][3][4][5] Specifically, some hardware-related challenges, such as stress shielding, bone holes, infection, and retained screws, are noteworthy.2][3][4][5] Thus, a previous preparatory surgery to remove the hardware and, when needed, to take tissue samples to exclude septic complications may be desirable, possibly making a subsequent THA surgery shorter, safer and less demanding. 2In the case of a THA after a previous femoral osteotomy, however, hardware removal was reported as troublesome in 24% of patients. 3Herein, a case of hip osteoarthritis after a proximal femoral osteotomy is presented.The patient was treated with a two-step approach (hardware removal preceding THA).Soon after the hardware removal, an iatrogenic subtrochanteric fracture occurred, which was successfully treated with a primary tapered long-stemmed THA without any additional osteosynthesis.

Case Presentation
A 78-year-old female was scheduled for THA in a dysplastic left hip.The patient complained about a recent onset of groin pain and a reduction in the articular excursion due to degenerative joint disease.The left hip had been treated with an intertrochanteric osteotomy 41 years prior to this case.A blade plate had been used to fix the osteotomy (Figure 1).The patient showed no local signs of infection, and her C-reactive protein was 0.32 mg/100 mL (normal value: <0.50 mg/100 mL).The patient was scheduled for a twostep approach (hardware removal preceding THA).The patient's age and the quality of the bone were considered, and the two-step approach was adopted in order to restore the bone stock after hardware removal and reduce the risk of iatrogenic fractures during stem positioning.
The patient had a body mass index of 26.4 kg/m 2 (165 cm and 72 kg) and unremarkable comorbidities.She was classified as ASA (American Society of Anesthesiologists) grade 2. The hardware removal was performed using a lateral approach on the previous scar.The removal was difficult; only one screw could be easily removed.The other 4 screws were removed using a trephine; thus, the lateral cortex was weakened.Due to possible additional risks related to the reduced bone stock (intraoperative fractures, stem subsidence), the conversion to a single-stage procedure, that is, immediate THA, was not performed.
The patient was then advised not to weight-bear until a proper bone stock restoration was achieved.After three months, while a toe touch weight-bearing was allowed, the patient started complaining of hip pain.After 15 days, the patient felt pain, was unable to walk, and had a shortened left lower limb (-2 cm).An iatrogenic subtrochanteric fracture occurred (Figure 1).To treat the fracture below the osteoarthritic hip, a revision THA was implanted.The same lateral incision was used, allowing a direct visualization of the fracture.First, the acetabulum was prepared as usual, and then a trabecular metal cup with a longevity polyethylene liner was implanted (Zimmer, Warsaw, US).On the femoral side, a proper fracture reduction was performed and maintained using reduction forceps.The fracture reduction was directly controlled while the femoral canal was prepared using progressive reamers.A tapered 190-cm long stem (Wagner, Zimmer, Warsaw, US) was implanted in order to bypass the fracture.Due to the good fracture stability, no additional osteosynthesis was performed.The lateral cortical bone loss was filled with autologous bone from reaming.The implant was then reduced using a 28-mm metal head (Figure 2).
After surgery, weight-bearing was not allowed.Toe touch weight bearing was allowed after 45 days.Complete weight bearing was delayed until the third month after surgery (Figure 2).After three years, the patient was painless, active, and independent, requiring a walking cane for long walks (Harris Hip score: 91 points).Radiographic examination revealed the healing fracture and a well-positioned implant with no signs of stem subsidence (Figure 2).

Discussion
Previous proximal femoral fixation was associated with a more demanding THA conversion. 2,3,5In particular, the presence of hardware was described as one of the most notable challenges, influencing the surgical approach, blood loss, operative time, and the implant choice, with increased risk of infections, fractures, and possible loosening. 2,3,5Despite the need for two surgical procedures, a two-step approach may provide a safer solution: the hardware can be removed in the first step and then, after the bone stock restoration, the THA can be performed. 2,5 wever, hardware removal before THA is associated with high rates of challenges and complications (24%).Systemic osteoporosis and local bone stock reduction due to stress protection have been reported as predisposing factors for fractures. 1,3In this case report, the age of the patient, the hardware-related stress shielding, and the arduous removal associated with broken screws requiring burs and trephines severely weakened the lateral cortex, resulting in a transverse subtrochanteric fracture.The conversion to a single-step procedure may have been beneficial in this case; however, due to the reduced bone stock and no strict indication (like frank fracture) to perform a demanding and risky surgery, the THA implantation was delayed.When the fracture occurred below the osteoarthritic hip, the chosen treatment was a THA with a revision stem.In fact, a simple reduction and fixation would have not Figure 1.Anterior-posterior X-ray of the showed an osteoarthritic hip in a mild dysplastic morphology: a femoral varus osteotomy with a blade-plate fixation was performed 41 years before (A).The anterior-posterior X-ray of the pelvis soon after the challenging hardware removal showed severe lateral bone loss and a very thin medial cortex at the level of the removed bone screws (B).The frontal CT scan 15 days later confirmed the situation (C).After 90 days, in two serial anterior-posterior X-rays of the pelvis, a varus angulation was evident, which ended in an iatrogenic, transverse subtrochanteric fracture (D and E).
addressed the articular degeneration and would have required another surgical procedure.Thus, a cementless highly porous cup with a polyethylene insert, a metal ball and a conical long stem was implanted.A conical stem may have provided a good distal (diaphyseal) fixation, bypassing the fracture and achieving a satisfying reduction, but as reduction and fixation was brilliantly achieved by the long stem, no additional osteosynthesis was required.
The use of the cementless long stem in cases of subtrochanteric fracture has been amply reported.Yuasa et al described a single case of atypical subtrochanteric fracture below an arthritic hip after a prolonged bisphosphonate therapy. 6A tapered modular THA with an additional osteosynthesis was adopted with good results.A 12-patient case series was provided by Oztürkmen et al. 7 The subtrochanteric fractures below arthritic hips were treated with cannulated, tapered long stems (Helios, Biomet, Warsaw, US).Cerclages and cables were used to avoid fracture propagation.A distal fracture and a greater trochanter fracture occurred.Encouraging results were described, with a mean Harris Hip score of 83 points and only one case of stem subsidence.The authors postulated that such a single procedure was demanding, but in the case of elderly patients, it might have provided a good alternative to two-step surgeries (fixation+THA).
Despite the appropriate differences, THAs after failed subtrochanteric fracture fixation may provide a good comparison with our case report.Only a few patients included in large case series have been described.Enocson et al reported 25 subtrochanteric fractures treated with total or partial hip arthroplasty procedures.Despite the inclusion of different approaches and devices, long stem implants performed better with a reduced risk of revision. 8hakur et al and Weiss et al respectively described 5 failed intertrochanteric fracture fixations with subtrochanteric extension and 20 failed subtrochanteric fracture fixations treated with tapered long stems; their clinical and radiographic results were good. 9,10

Conclusion
This case report highlighted two hot topics in complex THAs: the challenges presented by femoral hardware presence and the lack of consensus about the treatment of subtrochanteric fractures below osteoarthritic hips.Femoral hardware should be removed before THA, allowing bone stock restoration and ruling out latent sepsis.Unfortunately, a remote risk of fracture should be taken into account.When a difficult hardware removal is anticipated, a resurfacing or a mini-stem option should be evaluated, weighting the pros (no hardware removal) and the cons (metallosis) of this procedure.In the current case, the conversion to a single-stage procedure (THA with a tapered stem) immediately after the complicated hardware removal may have been the best solution; however, this procedure is really demanding, and the risk of intraoperative fractures and subsequent stem subsidence may be very high, particularly in elderly patients.Thus, this procedure should be limited to very selected cases in which the two-stage procedure is too physically demanding for the patient.In cases of a subtrochanteric fracture below an osteoarthritic hip, when a single procedure is recommended, a cementless tapered long stem implant seems to be a viable option.This stem bypasses the fracture, maintains a proper reduction, and achieves a good diaphyseal fixation.Additional osteosynthesis can be avoided if a good stability of the fracture is achieved with the stem acting as an internal fixator.

Figure 2 .
Figure 2. A tapered long stem was implanted, bypassing the fracture and obtaining a good reduction and fixation (A).After 45 days (B and C) and 3 years (D), the fracture showed progressive signs of healing and good osseointegration of the stem.