NEGLECTED BILATERAL FEMORAL NECK FRACTURES IN A PATIENT WITH END-STAGE RENAL DISEASE BEFORE CHRONIC DIALYSIS

Abstract

Bilateral femoral neck fractures are rarely reported in patients with end-stage renal disease before chronic dialysis. We report on a 39-year-old woman with neglected bilateral femoral neck fractures, who presented with severe uremic complications prior to chronic dialysis. Three years before admission, she had injured herself in a trivial slip with subsequent bilateral hip pain. She had progressively waddled since then. Pelvic X-ray taken after admission revealed bilateral femoral neck fractures. Bilateral hip hemiarthroplasties were subsequently performed. Displaced femoral neck fractures were found intraoperatively. Pathologic findings and results of examinations supported the coexistence of osteoporosis and high turnover renal osteodystrophy, rendering this woman at high risk of bilateral femoral neck fractures. Therefore, preventing a simple fall or trivial accident and treating renal osteodystrophy and osteoporosis are paramount in patients with chronic renal failure even before the start of dialysis therapy. We also emphasize the need to seek any possible underlying metabolic bone disease once a patient presents with unusual fractures.

• Bilateral femoral neck fractures
• End-stage renal failure
• Osteoporosis
• Renal osteodystrophy

INTRODUCTION

Renal osteodystrophy often develops insidiously in the early course of chronic renal failure and progresses without appropriate management. Both loss of mineralized bone quantity and quality of a mixture of fibrous tissue and loosely textured woven bone are responsible for the skeletal fragility and decreased bone strength in most patients with renal osteodystrophy [[1]]. In addition, chronic renal failure is among the risk factors for osteoporosis [[2]]. Thus, patients with chronic renal failure are susceptible to pathologic fractures. Pathologic hip fractures in end-stage renal disease patients undergoing maintenance hemodialysis have been reported [3-4], but these rarely present before long-term dialysis. Moreover, bilateral fractures of the femoral neck are rare [[5]]. Accordingly, it is very rare to demonstrate a 39-year-old woman with neglected bilateral femoral neck fractures associated with underlying chronic renal failure prior to long-term dialysis.

CASE REPORT

An acutely distressed 39-year-old woman with a history of anemia and renal failure was referred to our emergency department due to progressive shortness of breath for more than one month. Endotracheal intubation had been performed at the referring hospital. On physical examination, her consciousness was clear with blood pressure of 190/100 mmHg and a pulse rate of 102/min. Pale conjunctiva and diffuse moist rales of both lungs were also discovered. Laboratory studies showed azotemia (blood urea nitrogen 88 mg/dL, creatinine 15.2 mg/dL), anemia (hemogram 6.5 g/dL), severe metabolic acidosis (arterial pH 7.09, serum carbondioxide pressure 13.7 mmHg, oxygen presssure 291.1 mmHg, and bicarbonate 4.1 mmol/L), low normal albumin value (3.4 g/dL), hypocalcemia (5.1 mg/dL), hyperphosphatemia (10.8 mg/dL), and elevated alkaline phosphatase activity (170 U/dL). Chest X-ray showed pulmonary congestion without cardiomegaly. For severe uremic metabolic acidosis and pulmonary edema, emergent hemodialysis was arranged. She was successfully extubated 4 days after hemodialysis.

During admission, renal sonography revealed bilateral small and contracted kidneys. For maintenance hemodialysis, she received arteriovenous fistular creation. After stabilization, she complained of bilateral hip pain. Tracing back 3 years previously, she had injured herself in a trivial slip in the bathroom, resulting in bilateral hip pain. She ignored it and did not see any orthopedic doctors. From that time, she had walked with a progressive waddling gait and had reached the point where she was unable to walk about 1 month before this admission. Before that accident, fatigue, foamy urine, and leg edema had been present for a long time. No history of alcoholism or corticosteroid abuse was noted. Pelvic X-ray examination taken after admission disclosed bilateral femoral neck fractures (Figure 1). Further studies were performed to search for possible underlying diseases related to this unusual roentgenographic finding. The serum intact parathyroid hormone (i-PTH) value was elevated at 784 pg/mL. Parathyroid scan disclosed no parathyroid adenoma. The serum aluminum level was normal (0.8 μg/dL). Serum and urine immunoelectrophoresis revealed no paraproteins. No evidence of hyperthyroidism was found (T4: 15 (4.8–12.8) μg/dL, T3: 37.2 (52–175) ng/dL, and TSH: 4.97 (0.25–4.0) UIU/mL). Serum cortisol level was not low at 8 Am (19.7 μg/dL). Serum tumor markers were unremarkable (AFP<3.0 (<20) ng/mL, CEA: 2.59 (<5) ng/mL, CA125: 17.4 (3.8–34.5) U/mL). Bone scan studies showed diffusely active bone lesions probably related to metabolic bone disease with a relatively cold area in the right femoral head. Bone mineral density revealed osteoporosis with marked fracture risk in the lumbar spine and bilateral proximal femur.

Figure 1. Bilateral femoral neck fracture of this patient.

Right hip hemiarthroplasty was first performed about 1 month after admission, and intervention with left hip hemiarthroplasty occurred 1 week later. Operative findings included severe osteoporosis and displaced femoral neck fractures with absorbed fracture ends, which indicated old fractures. Pathologic findings showed bony fractures, featuring bony fragmentation with sequestration and scattered osteoclasts, and some bony regeneration, characterized by osteoid formation and trabeculae with osteoblastic rimming. No evidence of osteonecrosis of the femoral heads was identified.

Six weeks after the operation she could walk smoothly. There have been no major complaints about either hip within a 3-year follow-up. Meanwhile, she has continued maintenance hemodialysis.

DISCUSSION

Increased bone turnover may represent an independent risk factor for fracture [[6]]. High bone turnover is a condition of high activity of bone remodeling, causing increased cortical porosity [[1]]. As is known, osteoporosis is an important and main risk factor for proximal femoral fracture [[7]], and chronic renal failure is among the risk factors for osteoporosis [[2]]. Thus, through osteoporotic mechanisms, patients with end-stage renal disease without appropriate management of metabolic problems are vulnerable to proximal femoral fractures. Not only are decreased physical activity and gonadal dysfunction major risk factors for osteoporosis in patients with end-stage renal disease [[2]], but also uremic hyperparathyroidism plays an important contributing role to osteoporosis in them. In fact, increased parathyroid hormone secretion begins very early in the course of chronic renal failure. By the time creatinine clearance has fallen below 50 mL/min, parathyroid hormone hypersecretion of some degree is almost universal [[1]]. The concepts have been postulated that the i-PTH level must be 2.5 to 3 times the normal before the skeletal features of hyperparathyroidism are observed in end-stage renal disease patients and that the levels must be 5 to 7 times the normal before significant osteitis fibrosa is found in all patients [[8]]. The serum i-PTH level being as high as 12 times the upper normal value (10–65 pg/mL) with elevated alkaline phosphatase level in our patient indicates the presence of high turnover renal osteodystrophy, which is supported by the pathologic findings. Actually, not only does the enhanced loss of cortical bone mass quantity exist in patients with high turnover renal bone disease, but a decrease in quality of a mixture of fibrous tissue and loosely textured woven bone is also histologically identified in them [[1]]. Thus, the importance cannot be overemphasized of treating high turnover renal osteodystrophy in patients with chronic renal failure even before starting dialysis therapy, such as with dietary phosphate restriction, phosphate-binders use, calcimimetics supply, calcitriol administration, and parathyroidectomy [9-11].

By history taking, serum cortisol level, pelvic X-ray film, and pathologic findings, steroid-induced avascular femoral head necrosis was excluded in our patient, although a bone scan showed a relatively cold area in the right femoral head. Chronic renal failure is the only systemic disease deeply associated with her unusual bilateral femoral neck fractures, which is also supported by the report of Tarr et al. that chronic renal failure is an underlying condition that can predispose patients to insufficiency fractures of the femoral neck [[12]].

Patients with chronic renal failure are among those at high risk for osteoporosis and often gradually and subclinically develop renal bone disease from the early stage. Thus, early appropriate intervention to treat these complications is emphasized. Similarly, patients with other underlying pathologic bone disease are at high risk of fractures even if only a trivial injury occurs. Accordingly, emphasis should be placed on seeking the possible underlying metabolic bone disease such as chronic renal disease once a patient experiences unusual fractures.