Orthopaedic Surgeon, Haga Hospital, The Hague, The Netherlands.
Clin Orthop Relat Res. 2012 Dec;470(12):3284-96. doi: 10.1007/s11999-012-2511-4.
Developmental hip disorders (DHDs), eg, developmental dysplasia of the hip, slipped capitis femoris epiphysis, and femoroacetabular impingement, can be considered morphology variants of the normal hip. The femoroacetabular morphology of DHD is believed to induce osteoarthritis (OA) through local cumulative mechanical overload acting on genetically controlled patterning systems and subsequent damage of joint structures. However, it is unclear why hip morphology differs between individuals with seemingly comparable load histories and why certain hips with DHD progress to symptomatic OA whereas others do not.
QUESTIONS/PURPOSES: We asked (1) which mechanical factors influence growth and development of the proximal femur; and (2) which genes or genetic mechanisms are associated with hip ontogenesis.
We performed a systematic literature review of mechanical and genetic factors of hip ontogeny. We focused on three fields that in recent years have advanced our knowledge of adult hip morphology: imaging, evolution, and genetics. WHERE ARE WE NOW?: Mechanical factors can be understood in view of human evolutionary peculiarities and may summate to load histories conducive to DHD. Genetic factors most likely act through multiple genes, each with modest effect sizes. Single genes that explain a DHD are therefore unlikely to be found. Apparently, the interplay between genes and load history not only determines hip morphotype, but also joint cartilage robustness ("cartilotype") and resistance to symptomatic OA. WHERE DO WE NEED TO GO?: We need therapies that can improve both morphotype and cartilotype. HOW DO WE GET THERE?: Better phenotyping, improving classification systems of hip morphology, and comparative population studies can be done with existing methods. Quantifying load histories likely requires new tools, but proof of principle of modifying morphotype in treatment of DDH and of cartilotype with exercise is available.
发育性髋关节疾病（DHD），如髋关节发育不良、股骨头骨骺滑脱和股骨髋臼撞击症，可被视为正常髋关节的形态变异。DHD 的股骨髋臼形态被认为通过局部累积机械过载作用于遗传控制的模式系统，并随后对关节结构造成损伤，从而引发骨关节炎（OA）。然而，目前尚不清楚为什么具有相似负荷史的个体的髋关节形态存在差异，以及为什么某些患有 DHD 的髋关节会进展为有症状的 OA，而其他髋关节则不会。
问题/目的：我们提出了以下两个问题：（1）哪些机械因素会影响股骨近端的生长和发育；（2）哪些基因或遗传机制与髋关节的发生有关。
我们对髋关节发生的机械和遗传因素进行了系统的文献回顾。我们重点关注了近年来在成人髋关节形态学方面取得进展的三个领域：影像学、进化和遗传学。
机械因素可以从人类进化的特殊性来理解，并且可能会累积导致 DHD 的负荷史。遗传因素很可能通过多个基因起作用，每个基因的效应大小都适中。因此，不太可能找到可以解释 DHD 的单一基因。显然，基因与负荷史的相互作用不仅决定了髋关节的形态类型，还决定了关节软骨的坚固性（“软骨型”）和对有症状的 OA 的抵抗力。
我们需要能够改善形态类型和软骨类型的治疗方法。
使用现有的方法，可以进行更好的表型分析、改善髋关节形态分类系统以及比较人群研究。量化负荷史可能需要新的工具，但已经有证据表明，在治疗 DDH 时可以改变形态类型，通过运动改变软骨类型。
