Kwang-Kyoun Kim

Hypophosphatasia is a rare inherited metabolic bone disease caused by low activity of tissue-nonspecific alkaline phosphatase. Adult-onset hypophosphatasia is increasingly recognized, but fracture patterns and optimal management remain unclear. We report a 52-year-old woman who presented with progressive pain and bilateral atypical femoral fractures. She was diagnosed with hypophosphatasia based on low alkaline phosphatase, markedly elevated pyridoxal 5′-phosphate, a history of metatarsal fracture, premature tooth loss, and pathogenic ALPL variants. Low-dose asfotase alfa was started because standard-dose therapy was not feasible. After 6 months, callus formation was observed, and pain improved. However, 6 months later, the pain recurred, and radiographs showed a progressive fracture, suggesting insufficient fracture healing. Staged intramedullary fixation was performed for both femurs. Two perioperative femoral fractures occurred during the course of surgical management. Therefore, adjunctive teriparatide (20 µg daily for six months) was initiated while continuing low-dose asfotase alfa. At 5-year follow-up, radiographic union of all femoral fractures was achieved, and the patient remained ambulatory without assistance and had no fracture-related pain. This case shows that adult-onset hypophosphatasia can cause severe skeletal fragility and may require individualized multidisciplinary management, including biochemical diagnosis, long-term radiographic surveillance, cautious surgical planning, and selective use of medication.

Total hip arthroplasty (THA) is a successful surgical method for hip replacement but still poses challenges and risks. Robotic-assisted THA (rTHA) using new generation robotic systems has emerged to improve surgical precision and outcomes. The purpose of this paper is to review the literature on rTHA, with a focus on its advantages, such as individualized preoperative planning, intraoperative assistance, and improved accuracy in implantation, especially in complex cases. Additionally, it aims to explore the disadvantages associated with the use of rTHA, including high costs, the learning curve, and prolonged operation time compared to manual THA (mTHA), which are critical drawbacks that require careful consideration and efforts for minimization. Some financial analyses suggest that rTHA may offer cost-effectiveness and reduced postoperative costs compared to mTHA. While technological advancements are expected to reduce technical complications, there are still debates surrounding long-term outcomes. Practical limitations, such as limited availability and accessibility, also warrant attention. Although the development of rTHA shows promise, it is still in its early stages, necessitating critical evaluation and further research to ensure optimal patient benefits.

Kim KK, et al. Clin Orthop Surg. 2022 Nov;14:e91. https://doi.org/10.4055/cios22147

Kim K, et al. Hip Pelvis. 2021 Jun;33(2):45-52. https://doi.org/10.5371/hp.2021.33.2.45

Of the drugs developed to prevent and treat osteoporosis, bisphosphonate has played a very important role in preventing osteoporotic fractures. However, case reports describing atypical femoral fractures in patients using long-term bisphosphonates have emerged. The majority of atypical femur fractures occurs in the lateral aspect of the subtrochanteric or femur diaphysis, which is explained by accumulation of tensile stress in these areas. Although the superior cortex of the femur neck withstands maximum tensile stress, to our knowledge, there have been only two reports (three cases) of atypical femoral neck fracture. In addition, none of those case reports revealed detailed pathology related to suppressed bone turnover rate. We encountered an incomplete femoral neck fracture and diagnosed it as "atypical" on the basis of the patient's lack of trauma and medication history and pathological findings. For patients with groin pain, minimal or no trauma, and a history of long-term bisphosphonate use, an atypical femoral neck fracture should be considered.