Metabolic Bone Diseases and Total Hip Arthroplasty: Preventing Complications

Joaquin Moya-Angeler, MD, PhD; Joseph M. Lane, MD; Jose A. Rodriguez, MD

Disclosures

J Am Acad Orthop Surg. 2017;25(11):725-735. 

In This Article

Abstract and Introduction

Abstract

Metabolic bone diseases are a diverse group of conditions characterized by abnormalities in calcium metabolism and/or bone cell physiology. These unbalanced processes can eventually lead to bony deformities and altered joint biomechanics, resulting in degenerative joint disease. Not infrequently, patients with metabolic bone diseases have restricting hip joint pain that ultimately necessitates hip arthroplasty. To minimize complications, the surgeon must consider the particular characteristics of these patients. The surgical and medical management of patients with metabolic bone diseases undergoing hip arthroplasty requires appropriate preoperative diagnosis, careful attention to the technical challenges of surgery, and strategies to maximize the long-term results of the surgical intervention, such as the use of bone anabolic and anticatabolic agents.

Introduction

Metabolic bone diseases (MBDs) are a diverse group of conditions characterized by abnormalities in calcium metabolism and/or bone cell physiology.[1] These unbalanced processes can eventually lead to bony deformities and altered joint biomechanics, resulting in degenerative joint diseases.[2] Not infrequently, patients with MBDs have restricting hip joint pain that ultimately necessitates hip arthroplasty.[1,3,4] Most of the problems that make total hip arthroplasty (THA) difficult in these patients can be anticipated by thoroughly understanding the disease and ensuring careful preoperative evaluation and planning. To minimize complications, specific patient characteristics must be considered.

The most common type of MBD in developed countries is osteoporosis, and its prevalence is increasing as the average age of people rises.[4] The estimated number of adults with osteoporosis and low bone mass is 53.6 million, representing approximately 54% of the US adult population aged ≥50 years.[4] Other less common MBDs that can either coexist with or lead to hip osteoarthritis (OA) should be considered when evaluating patients undergoing THA.[5] These diseases include atypical femoral fractures (AFFs), osteonecrosis of the femoral head, osteomalacia, Paget disease, fibrous dysplasia, and osteogenesis imperfecta.[1,5–12] With the availability of treatments that can cure, prevent, or control most MBDs, early recognition is essential. Ultimately, all patients undergoing hip arthroplasty with a suspected metabolic bone abnormality should receive special preoperative care (Figure 1). Findings from the history and examination vary according to the MBD in question and are usually nonspecific. Basic questions that should be asked of all patients include history of fractures, history of osteoporosis, past use of diphosphonates, history of alcohol abuse, excessive steroid use, coagulopathy, blood dyscrasia, malignancy, systemic inflammatory disease, HIV, and hyperlipidemia. Associated radiographic abnormalities, such as low bone density, proximal femoral deformities, or protrusio acetabuli, can also raise suspicion of a concomitant MBD (Table 1). In general, for any patient undergoing hip arthroplasty, bone health should be evaluated preoperatively.[12] Clinicians should monitor patients' levels of calcium and vitamin D perioperatively.[13] The recommended adult level of vitamin D is ≥20 ng/mL (600 IU of vitamin D daily for persons aged 19 to 70 years and 800 IU for persons aged >70 years). However, most experts agree that even higher levels are advantageous among patients with MBDs, especially osteoporosis, and that sufficient intake of calcium and vitamin D to prevent secondary hyperparathyroidism is the best marker of adequate calcium and vitamin D intake in any patient.[13] Postmenopausal women, men aged >70 years, and men and women with risk factors for osteoporosis should undergo bone densitometry within 2 years of surgery.[12] The Fracture Risk Assessment Index is a multifactorial index used to predict fracture risk. It integrates relevant information about a patient, such as age, weight, height, history of low-impact fracture, use of steroids, and bone mineral density. Pharmacologic treatment is recommended for patients with osteoporosis or osteopenia and/or an elevated Fracture Risk Assessment Index (≥20% overall risk of fracture or ≥3% risk of hip fracture).[12]

Figure 1.

Algorithm for the preoperative evaluation of patients undergoing elective total hip arthroplasty. 1 = positive findings, 2 = negative or normal findings, AFF = atypical femoral fracture, MBD = metabolic bone disease

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