Bilateral Femoral Neck Fractures in a 50-Year-Old Patient with Chronic Kidney Disease

Introduction

Chronic kidney disease (CKD) is associated with multiple metabolic disorders. A frequent cause of concern is the disturbance of bone and mineral metabolism among CKD patients. Abnormalities in the bone structure and mineral metabolism develop early in the course of CKD and are directly proportional to the gradual loss of kidney function. As CKD advances, the risk of femoral fractures also escalates proportionally and so does the mortality associated with such fractures [1].

The pathophysiology of renal osteodystrophy in CKD is primarily attributed to the decreased excretion of phosphorus. The resultant hyperphosphatemia blocks the renal conversion of vitamin D to its active form. Hyperphosphatemia also depletes the calcium levels in the blood, leading to hypocalcemia, which in turn triggers secondary hyperparathyroidism. Bone resorption occurs due to hyperparathyroidism to restore normal calcium levels.

The prevalence of CKD is estimated to be nearly 10% of the total population [2]. Past evidence has revealed that it is a characteristic feature, invariably present in all CKD patients [3,4].

We present a rare case of bilateral femoral neck fractures that resulted from an episode of tonic-clonic seizure, without history of a fall or trauma, in a patient with stage 4 CKD. This case adds interesting clinical experience to the limited body of evidence on bilateral femoral fragility fractures in CKD patients. These fractures are quite uncommon, constituting less than 1% of all adult fractures [5].

Case Report

A 50-year-old man, known to be at stage 4 of CKD, presented to the Emergency Department of our hospital for the first time following an episode of generalized tonic-clonic seizure that started in his sleep, and generalized muscle pain. The seizure lasted nearly 4 min and then subsided on its own, with no post-ictal period, as per the patient. The patient had a similar attack 3 years previously; however, unlike the recent seizure, that episode had not been followed by any complications.

The patient stated that he had been experiencing severe and excruciating pain in both hips since the last seizure episode; the pain was sharp, not radiating, and was aggravated by any movement of the hips.

A radiograph (X-ray) of the pelvis revealed bilateral femoral neck fractures (Figure 1). An urgent orthopedic consultation occurred. It was recommended to stabilize the patient, treat his severe electrolyte imbalance (K=3, Mg=0.4, Ca=1.43), and then perform surgery. The exact cause of the electrolyte imbalance was not clear; however, it was most probably due to impaired kidney function and electrolyte imbalance. The patient was moved to the Intensive Care Unit (ICU) for the correction of the electrolyte imbalance, and his renal function was monitored daily. At the end of his stay in the ICU, his acidemia resolved and his potassium and magnesium levels normalized. Moreover, since his admission, he had not experienced any more seizure episodes. Once he was deemed fit for surgery, bilateral hemiarthroplasty for the femoral neck fractures was performed. The surgery was successfully accomplished with no intraoperative or postoperative complications. The patient was allowed to start weight-bearing as tolerated and physiotherapy was initiated. No hip flexion beyond 90 degrees, no hip internal rotation beyond neutral, and no hip adduction beyond neutral was allowed for 6 weeks. Full hip ROM and strengthening exercises were initiated 6 weeks postoperatively.

A postoperative X-ray revealed a well-fixed prosthesis without evidence of subsidence, periprosthetic fracture, or any other complications (Figure 2). He was routinely followed up at the orthopedic outpatient clinic. At the last follow-up visit, he was adequately mobile and physically comfortable and had resumed his daily activities.

Discussion

CKD imposes a huge medical and economic burden on the healthcare and social ecosystems. Global estimates reveal that more than 10% of the general population suffers from CKD, amounting to roughly 800 million CKD patients worldwide [6,7]. The incidence is greater in known high-risk subgroups such as the elderly, diabetics, hypertensives, and smokers, among others. In the last 3 decades, the world has witnessed a greater than 40% rise in mortality due to CKD. It has a varying pattern of prevalence in different regions of the world, perhaps due to differences in population demographics, comorbidities, and access to medical facilities [8].

The adverse effects of CKD on bone health have become a daunting clinical challenge and represent a continuum of bone pathologies frequently referred to as “CKD mineral and bone disorders (CKD-MBD)”. Renal osteodystrophy is a component of CKD-MBD and is a frequent complication encountered in advanced CKD and end-stage renal disease (ESRD) [9]. Renal osteodystrophy is a broad term that encompasses all the biochemical abnormalities and skeletal manifestations in advanced CKD and ESRD patients. Histopathologically, it is classified as high bone turnover states, such as osteitis fibrosa and hyperparathyroidism, and low bone turnover states, such as dynamic bone disease and heavy metal-induced osteomalacia. However, the typical presentation of renal osteodystrophy is the high bone turnover state, characterized by hypocalcemia, low vitamin D, hypophosphatemia, and secondary hyperparathyroidism that triggers bone resorption. Therefore, fragility fractures are common in patients with renal osteodystrophy [10].

In this case, after clinically correlating the recent seizure history and symptoms with the severe electrolyte disturbance, it was evident that the patient suffered from renal osteodystrophy secondary to advanced CKD. Vigorous muscular contractions during the tonic-clonic seizure had a significant impact on the osteodystrophic femur, leading to femoral neck fracture. However, to our surprise, the femoral neck fracture was bilateral. This is a very rare finding; bilateral femoral neck fractures constitute less than 1% of all adult fractures [5].

The rate of femoral fractures has seen an exponential rise over the past few decades and current reports suggest that the number of these fractures will reach 6.3 million by the year 2050 [11]. This prediction seems quite alarming, especially in the context of advanced CKD and ESRD, as the risk of such fractures is significantly higher in these conditions. The incidence of hip fractures is 4 times higher in dialysis patients than in the general population; the risk remains significantly higher even in mild-to-moderate CKD cases [12,13]. The 1-year mortality rate after hip fracture has been estimated to be 55–64% for dialysis patients, which is 2.7 times the rate for their non-fractured dialysis counterparts. Higher mortality rates have been reported, even for patients with mild-to-moderate CKD who have hip fractures, than in those without such fractures [13]. Hence, the determining the optimal surgical management of femoral fragility fractures in CKD patients is of paramount importance for reducing the related morbidity and mortality.

Our choice of hemiarthroplasty as a surgical procedure was driven by multiple factors, including patient age, presence of CKD, delayed presentation, and the fact that hemiarthroplasty provides better functional outcomes and has a shorter time to weight-bearing compared to other procedures, such as the dynamic hip screw [14]. In a cohort of more than 70 000 patients who underwent surgery for femoral neck fractures, Wang and Bhattacharya reported that 95% of patients underwent hemiarthroplasty. Its rate of dislocation and revision surgery is significantly lower than that of total hip arthroplasty [15]. Data from large hip fracture registries of the Royal College of Physicians in London and the UK National Health Service show that 90% of all femoral fractures are treated surgically with hemiarthroplasty, while only 10% of these patients undergo total hip replacement [16].

Postoperatively, we followed a meticulously planned physiotherapy protocol in the hospital, with physiotherapy sessions to be continued at home. Regular follow-ups were conducted at our outpatient clinic. We firmly endorse the broadly accepted view that physiotherapy is an integral part of post-surgical care after hemiarthroplasty. It facilitates quicker recovery, minimizes complications, and allows patients to achieve maximum functionality and physical independence after surgery [17].

This rare case of bilateral femoral neck fracture draws attention to the complications of CKD and its adverse impact on the healthcare system. Past evidence reveals that the level of understanding and knowledge of CKD among the general population is quite poor, especially in developing countries [8]. Poor awareness leads to delayed diagnosis and treatment, which in turn escalates the risk of CKD complications. This highlights the need to educate the general population through large-scale awareness and education campaigns on risk factors, associated comorbidities, precautions, and treatment options for CKD. Increased awareness, through concerted and systematic effort, could substantially reduce the morbidity and mortality associated with CKD in the long term [18]. Furthermore, those who are already suffering from CKD need to be educated about the importance of regular medical follow-up and adherence to treatment.

Conclusions

In advanced CKD, femoral fragility fractures secondary to renal osteodystrophy carry a significant risk of morbidity and mortality. This is a rare report of a case of bilateral femoral neck fragility fractures secondary to renal osteodystrophy in a stage 4 CKD patient. It draws the attention of the medical community to the high risk of bone disorders in CKD patients. Hemiarthroplasty is a safe, convenient, and highly efficacious surgical option in managing such cases. Pre-surgical stabilization of the patient and post-surgical care with optimum physiotherapy form crucial elements in the overall surgical management. Improved awareness and knowledge in the general population about the causes, risks, complications, and management of CKD can facilitate the early diagnosis and better treatment of this condition, which could substantially mitigate the associated morbidity and mortality.