Journal of Bone and Joint Diseases

CASE REPORTS
Year
: 2022  |  Volume : 37  |  Issue : 1  |  Page : 26--29

Atypical fixation failure after the internal fixation of a peri-implant subtrochanteric fracture in a patient on long-term bisphosphonate therapy and its management: An interesting case report


Arulkumar Nallakumarasamy, Rajkumar Arya, Shivam Sinha, Rahul Yadav 
 Department of Orthopaedics, Institute of Medical Sciences, Banaras Hindu University (IMS-BHU), Varanasi, Uttar Pradesh, India

Correspondence Address:
Arulkumar Nallakumarasamy
Department of Orthopedics, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, Uttar Pradesh
India

Abstract

Bisphosphonate therapy should be properly monitored in the treatment of osteoporosis, since it affects the bone turnover and may cause fatigue fractures. A new clinical adverse outcome due to long-term bisphosphonate therapy specifically in a postoperative osteoporotic patient is peri-implant fractures that are rarely described in the literature. Our case report describes an untoward biomechanical failure in the fixation of a peri-implant subtrochanteric fracture in an osteoporotic patient who is on long-term alendronate therapy and had been operated previously with dynamic hip screw and its management with 1-year follow-up.



How to cite this article:
Nallakumarasamy A, Arya R, Sinha S, Yadav R. Atypical fixation failure after the internal fixation of a peri-implant subtrochanteric fracture in a patient on long-term bisphosphonate therapy and its management: An interesting case report.J Bone Joint Dis 2022;37:26-29


How to cite this URL:
Nallakumarasamy A, Arya R, Sinha S, Yadav R. Atypical fixation failure after the internal fixation of a peri-implant subtrochanteric fracture in a patient on long-term bisphosphonate therapy and its management: An interesting case report. J Bone Joint Dis [serial online] 2022 [cited 2022 Nov 27 ];37:26-29
Available from: http://www.jbjd.in/text.asp?2022/37/1/26/345166


Full Text



 Introduction



Bisphosphonate (BP) therapy is often started in old-age patients with osteoporosis, as they increase bone density and reduce the risk of further fractures.[1] In contrast, it has been seen that long-term BP therapy increases the risk for atypical fractures and also may be a potential causative agent for second hip fractures[2] in patients with a history of prior hip surgeries when it has been used explicitly in the postoperative period for a longer duration without drug holidays.

In this case report, we discuss an unusual biomechanical failure in a 70-year-old female patient on long-term alendronate therapy that presented with a peri-implant subtrochanteric fracture 8 years after sustaining an intertrochanteric fracture treated with a dynamic hip screw (DHS). It is rare to see a case with peri-implant atypical femoral fracture (AFF) and its associated complications in the literature.

 Case Presentation



A 70-year-old woman presented to the emergency room with complaints of pain in her right hip with inability to get up following a trivial injury in her home. She had a history of a previous fracture in the intertrochanteric region of the same hip 8 years ago due to a slip and fall in her bathroom; it was managed at that time with DHS, the postoperative period was uneventful, and since then, she has been on alendronate 70 mg once weekly therapy. There was tenderness with swelling over the proximal hip and abnormal mobility at the same site on examination. There is shortening, and external rotation of her right lower limb without any neurovascular deficit and her vitals were stable.

The patient was subjected to the radiological examination of both hip with thigh AP and lateral views; it shows transverse peri-implant fracture just distal to the DHS plate with cardinal radiographic features of AFFs[3] and significant anterolateral bowing of contralateral femur as shown in [Figure 1]. AFF can occur where the stress concentration is higher because of the limited remodeling process. It was primarily immobilized with an above-knee Buck’s skin traction. Our dilemma was between hardware removal and fixation with load-bearing or load-sharing devices. For which we reviewed the literature, it has shown that the hardware removal might get difficult and may cause inadvertent iatrogenic fracture[4] or even may shatter the proximal femur when the patient is on long-term BP therapy. There is bowing of the entire femur, hence to avoid those complications, we opted for open reduction and internal fixation with 4.5 mm broad LCDCP with the usual surgical technique, and the immediate post-op X-ray was satisfactory, as shown in [Figure 2].{Figure 1} {Figure 2}

The patient was advised to avoid stopping alendronate and avoid weight-bearing 6 weeks, and she was prescribed calcitriol. Despite non-weight bearing, the patient was diagnosed with refracture and splinter in the distal fragment at the screw insertion site and implant failure at a 4week follow-up period, as shown in [Figure 3]. The patient was again posted for surgery, and this time all the hardware had been removed meticulously, and fixation was done with antegrade femur interlock nail without bone grafting as shown in [Figure 4]. At 1-year follow-up, the results were observed with a good clinical outcome even though the radiological union is limited due to decreased bone turnover rate, as shown in [Figure 5].{Figure 3} {Figure 4} {Figure 5}

 Discussion



Biomechanical failure after plate osteosynthesis in a BP-induced peri-implant subtrochanteric fracture is a rare entity described in the literature. Even though load sharing devices are the implant of choice for subtrochanteric fractures, we have attempted the fixation of the peri-implant fracture by plate osteosynthesis because of the fear of causing iatrogenic fracture during hardware removal, the chance of refracture at the barrel hole site in an osteoporotic bone[5] and considering the anterolateral bowing.

BP-induced subtrochanteric fracture is a serious complication. Due to the “bone freezing effect” of BPs, the microcracks keep accumulating in the dense cortical bone, typically in the tensile side near the isthmus. The inhibition of osteoclast’s function can affect the remodeling process and may produce low turnover fractures.[6] It has been found that the incidence of AFFs is around 1–2/1 lakh/year in patients exposed to BP for less than 2 years, whereas it increases to more than 100/1 lakh/year for those who kept on taking for more than 5 years,[7] other risk factors include bowing of the proximal femur which increases the tensile stress, a neck-shaft angle less than 125 (higher femoral offset), higher femoral torsion and shorter height.

Bardia et al.[4] described a case of iatrogenic fracture neck femur during DHS removal in a patient diagnosed with a subtrochanteric fracture on long-term alendronate therapy. Because of the unexpected complication, they did a total hip replacement procedure and not osteosynthesis in an osteoporotic woman.

Weil et al.[8] showed that second hip surgeries were required in 44% of the patients treated even with intramedullary nail fixation due to delayed union. In a series of 17 cases, only 54% of the patients and 46% of the required second hip surgeries. Teo et al[9] 33% of the patients required revision surgery, and 23% had implant failure.

In this case, the fixation was done with only three cortices on the distal fragment, which might have hastened the failure rate. Using longer plates or locking plates could have provided higher stability to the construct and may prevent early failures. Even in short-term follow-up, without weight-bearing, the failures of the surface implant were inevitable in an alendronate-treated osteoporotic bone due to inhibition of endochondral ossification. The choice of ideal fixation implant for atypical subtrochanteric and femoral shaft fractures is still under evaluation, and there is no widely accepted guideline yet.[10] Various deforming forces acting in the subtrochanteric region tend to displace the fracture fragments; hence, a better understanding of them is essential to accurately reduce fracture gap and offload the high stresses even in load-sharing implants to prevent hardware failure.[11] Although the complete radiological union is not evident in a BP-treated bone,[12] load sharing devices provide an excellent functional outcome and prevent reoperations in geriatric populations.[13],[14]

 Conclusion



In this case, the irrational usage of alendronate decreases the bone turnover rate in the subtrochanteric region, specifically at the stress point (edge of the DHS plate) that causes the peri-implant fracture. The fracture was managed with cephalo-medullary nailing, but the radiological union at 1-year follow-up was not that evident because of impaired bone remodeling in a BP-treated bone. Hence, a high level of vigilance is needed in patients on BP therapy. Further, surface implants tend to fail because of the inherent distractive muscle forces across the fracture site in this region and the poor reparative process at the fracture and screw site.

Our primary aim is to prove the facts of impaired or delayed bone healing, implant failures, and increased risk of reoperations in such cases. Meticulous preop planning and alternate implant options should be made available in an operating room since hardware removal may fail or an iatrogenic fracture may occur.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Not applicable.

Conflicts of interest

There are no conflicts of interest.

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