Post-hip fracture knee pain in older adults: a narrative review

Kaizu, Yoichi1; Miyata, Kazuhiro2,*

1Department of Rehabilitation Center, Hidaka Rehabilitation Hospital, Gunma, Japan

2Department of Physical Therapy, Ibaraki Prefectural University of Health Science, Ibaraki, Japan

*Correspondence to: Kazuhiro Miyata, RPT, PhD, miyatak@ipu.ac.jp.

Abstract

Hip fractures in older adults represent a growing public health concern, driven by aging populations and a rising fracture incidence. Post-hip fracture knee pain, a novel concept of adjacent joint injury, has been observed in up to one-third of older adults following surgery. Potential risk factors include the fracture type, the varus neck-shaft angle, and limited knee-extension range of motion. Although the precise pathomechanism of post-hip fracture knee pain is unclear, rapid changes in knee loading and the aggravation of pre-existing knee osteoarthritis seem critical. The etiology of post-hip fracture knee pain likely emerges from an interplay of skeletal integrity, inflammation, and biomechanical stress, echoing the broader complexities of aging. Clinically, post-hip fracture knee pain can prolong hospital stays and reduce walking speed, underlining the need for targeted assessment and rehabilitation strategies. The current evidence is based mostly on retrospective investigations, emphasizing the need for prospective studies to determine the prevalence and mechanisms. Future research should incorporate a three-dimensional gait analysis and ultrasound imaging to clarify the pathomechanism and develop effective interventions such as weight-bearing adjustments, alignment modifications, and targeted muscle strengthening. Post-hip fracture knee pain may significantly burden older adults recovering from hip fractures, especially within the context of ongoing musculoskeletal aging. A better understanding of post-hip fracture knee pain’s pathophysiology and management is pivotal for improving patient outcomes, ensuring more efficient rehabilitation, and reducing the overall impact of hip fractures in this vulnerable population.

老年人髋部骨折后的膝关节疼痛： 叙述性综述

摘要

由于人口老龄化和骨折发生率上升，老年人髋部骨折日益成为公共卫生问题。髋部骨折后膝关节疼痛（PHFKP）是一种新的邻近关节损伤概念，多达三分之一的老年人在手术后会出现这种疼痛。潜在的风险因素包括骨折类型、颈轴外翻角度和膝关节伸展活动范围受限。虽然 PHFKP 的确切病理机制尚不清楚，但膝关节负荷的快速变化和原有膝关节骨关节炎的加重似乎是关键因素。PHFKP 的病因可能来自于骨骼完整性、炎症和生物力学压力的相互作用，这与衰老的复杂性不谋而合。在临床上，PHFKP 会延长住院时间并降低行走速度，因此需要有针对性的评估和康复策略。目前的证据大多基于回顾性调查，因此强调有必要进行前瞻性研究，以确定发病率和发病机制。未来的研究应结合三维步态分析和超声波成像，以明确病理机制并制定有效的干预措施，如负重调整、排列调整和有针对性的肌肉强化。PHFKP 可能会给从髋部骨折中恢复过来的老年人带来沉重负担，尤其是在肌肉骨骼持续老化的背景下。更好地了解 PHFKP 的病理生理学和管理对改善患者预后、确保更高效的康复以及减少髋部骨折对这一弱势群体的整体影响至关重要。