Oka Naohiro, Mori Shigeshi, Shinyashiki Yu, Shokaku Nobuhisa, Yamazaki Kenji, Goto Koji, Togawa Daisuke
Department of Orthopedic Surgery, Kindai University Nara Hospital, Ikoma, Nara, Japan.
Department of Orthopedic Surgery, Kindai University Faculty of Medicine, Osakasayama, Osaka, Japan.
Case Rep Orthop. 2025 Apr 24;2025:7710384. doi: 10.1155/cro/7710384. eCollection 2025.
Herein, we present a rare case of periprosthetic joint infection (PJI) which was triggered by an infection with a latent subcutaneous cyst on the thigh and occurred in a strange course following total knee arthroplasty (TKA). An 87-year-old female underwent right TKA followed by left TKA 5 months later. Six weeks after left TKA, a painful subcutaneous induration appeared in the left medial thigh. Magnetic resonance imaging revealed a 30∗50-mm multifocal mass. The cystic fluid was brown and cloudy, indicating an infected cyst. Oral antimicrobial therapy was initiated for 7 days. Nine weeks after the left TKA, a left calcaneal fracture occurred. Subsequently, edema of the lower extremities and pain in the left knee gradually developed. Arthrocentesis was performed twice: joint fluid Gram staining and culture examination were negative. However, at 12.5 weeks, an alpha-defensin test of the synovial fluid was positive. Therefore, PJI was diagnosed. DAIR was performed, followed by multiantibiotic therapy. The infection subsided gradually. Edema of the lower limbs was treated with oral diuretics, lymphatic massage, and compression stockings. Consequently, the lower limb edema also improved. In this case, infection of a latent subcutaneous cyst in the thigh occurred and spread around the prosthesis due to leg edema, which was associated with loss of lower limb motion due to a calcaneal fracture. The presence of a potential thigh subcutaneous cyst is a risk factor for PJI. Moreover, lower extremity edema occurs by decreasing lower extremity motion, such as after a calcaneal fracture, and it increases the risk of extending extra-articular infection to the PJI. Potential thigh subcutaneous cysts and lower extremity edema are risk factors for the development of PJI. Orthopedic surgeons need to be aware of these facts during follow-up after TKA.
在此，我们报告一例罕见的人工关节周围感染（PJI）病例，该感染由大腿部潜伏性皮下囊肿引发，且在全膝关节置换术（TKA）后呈现出异常病程。一名87岁女性接受了右膝TKA，5个月后又进行了左膝TKA。左膝TKA术后6周，左大腿内侧出现疼痛性皮下硬结。磁共振成像显示一个30×50毫米的多灶性肿块。囊液呈褐色且浑浊，提示囊肿感染。开始口服抗菌治疗7天。左膝TKA术后9周，发生了左跟骨骨折。随后，下肢水肿和左膝疼痛逐渐出现。进行了两次关节穿刺：关节液革兰氏染色和培养检查均为阴性。然而，在12.5周时，滑液的α-防御素检测呈阳性。因此，诊断为PJI。进行了清创、抗生素保留植入物治疗（DAIR），随后进行了联合抗生素治疗。感染逐渐消退。下肢水肿采用口服利尿剂、淋巴按摩和弹力袜治疗。结果，下肢水肿也有所改善。在该病例中，大腿部潜伏性皮下囊肿发生感染，并因腿部水肿在假体周围扩散，而腿部水肿与跟骨骨折导致的下肢活动丧失有关。潜在的大腿皮下囊肿是PJI的一个危险因素。此外，下肢活动减少，如跟骨骨折后，会导致下肢水肿，增加关节外感染扩展至PJI的风险。潜在的大腿皮下囊肿和下肢水肿是PJI发生的危险因素。骨科医生在TKA术后随访期间需要了解这些情况。
