Gourineni Prasad, Valleri Durgaprasad, Mungalpara Nirav, Mahapatra Sudhir, Senthil Vishnu
Department of Orthopaedic Surgery, Amara Hospital, Karakambadi, AP 517520 India.
Department of Orthopaedic Surgery, Madras Medical College, Chennai, TN India.
Indian J Orthop. 2024 Jan 9;58(2):204-209. doi: 10.1007/s43465-023-01082-3. eCollection 2024 Feb.
Hip impingement from slipped epiphysis and idiopathic cam is well known but not fully differentiated. Idiopathic cam can be a result of an undiagnosed slip. The mechanism of remodeling of slipped epiphysis deformity has also been controversial. The causes of recurrent femoral head deformity and new impingement beyond progression of the slip have not been studied.
A consecutive series of hips treated by arthroscopic femoral neck osteoplasty for impingement from slipped epiphysis were compared with a series of hips treated for idiopathic cam impingement. Demographics and clinical, radiographic, and arthroscopic features were retrospectively retrieved. The same parameters were studied in another consecutive series of hips treated for slipped epiphysis and developed recurrent pain from impingement. The deformity was analyzed to understand the causes of recurrence in these hips. The medial most point where the femoral head sphericity ended was called the Alpha point and the tissue covering the bone at the Alpha point was identified.
Children with idiopathic cam were older, had less pain and limp, and less clinical deformity compared to those with slipped epiphysis. The damage pattern was chondrolabral separation and acetabular cartilage debonding from the subchondral bone by an articular cartilage covered bump in idiopathic cam impingement, while it was labral crushing and labral and cartilage abrasion by metaphyseal bone in slip impingement. Recurrent cam deformities after initial slips were from epiphyseal extension similar to the idiopathic cam deformity in 7 out of 9 hips.
Slipped epiphysis and idiopathic cam seem to be distinct entities at the time of presentation. They were different in all findings except for having pain with flexion and internal rotation in both groups. Remodeling of slip deformity seems to occur by wear of the metaphyseal prominence on the acetabulum. Recurrence or worsening of cam deformity in slips occurred by growth of the epiphysis on to the neck anteriorly which can appear as a decrease in the posterior slip. The relationship of the Alpha point to the physeal scar and the tissue covering the femoral head at the Alpha point help differentiate between epiphyseal and metaphyseal cam deformities.
Level 3 retrospective comparative study.
骨骺滑脱和特发性凸轮撞击导致的髋关节撞击已为人所知，但尚未完全区分。特发性凸轮撞击可能是未诊断出的骨骺滑脱的结果。骨骺滑脱畸形的重塑机制也一直存在争议。除了骨骺滑脱进展之外，复发性股骨头畸形和新的撞击的原因尚未得到研究。
将一系列因骨骺滑脱撞击而接受关节镜下股骨颈截骨术治疗的髋关节与一系列因特发性凸轮撞击而接受治疗的髋关节进行比较。回顾性收集人口统计学以及临床、影像学和关节镜特征。在另一组因骨骺滑脱而接受治疗并因撞击出现复发性疼痛的连续髋关节系列中研究相同参数。分析畸形情况以了解这些髋关节复发的原因。将股骨头球形度终止的最内侧点称为阿尔法点，并确定阿尔法点处覆盖骨骼的组织。
与骨骺滑脱患儿相比，特发性凸轮撞击患儿年龄更大，疼痛和跛行症状更少，临床畸形也更少。在特发性凸轮撞击中，损伤模式是软骨唇分离以及髋臼软骨通过关节软骨覆盖的隆起从软骨下骨剥离，而在骨骺滑脱撞击中，损伤模式是唇状挤压以及干骺端骨导致的唇状和软骨磨损。9例髋关节中有7例在初次骨骺滑脱后出现的复发性凸轮畸形是由于骨骺延伸，类似于特发性凸轮畸形。
在就诊时，骨骺滑脱和特发性凸轮撞击似乎是不同的实体。除了两组在屈曲和内旋时均有疼痛外，它们在所有检查结果上均有所不同。骨骺滑脱畸形的重塑似乎是由于髋臼上干骺端突出部位的磨损。骨骺滑脱中凸轮畸形的复发或加重是由于骨骺向前生长到颈部，这可能表现为后侧骨骺滑脱减少。阿尔法点与骨骺瘢痕的关系以及阿尔法点处覆盖股骨头的组织有助于区分骨骺性和干骺端性凸轮畸形。
Ⅲ级回顾性比较研究。
