Search

IntroductionPopliteal cysts are secondary to degenerative changes in the knee joint. After total knee arthroplasty (TKA), 56.7% of patients with popliteal cysts at 4.9 years follow-up remained symptomatic in the popliteal area. However, the result of simultaneous arthroscopic cystectomy and unicompartmental knee arthroplasty (UKA) was uncertain.Case presentationA 57-year-old man was admitted to our hospital with severe pain and swelling in his left knee and the popliteal area. He was diagnosed with severe medial unicompartmental knee osteoarthritis (KOA) with a symptomatic popliteal cyst. Subsequently, arthroscopic cystectomy and unicompartmental knee arthroplasty (UKA) were performed simultaneously. A month after the operation, he returned to his normal life. There was no progression in the lateral compartment of the left knee and no recurrence of the popliteal cyst at the 1-year follow-up.ConclusionFor KOA patients with a popliteal cyst seeking UKA, simultaneous arthroscopic cystectomy and UKA are feasible with great success if managed appropriately.

The behavior of nerve cells plays a crucial role in nerve regeneration. The mechanical, topographical, and electrical microenvironment surrounding nerve cells can activate cellular signaling pathways of mechanical transduction to affect the behavior of nerve cells. Recently, biological scaffolds with various physical properties have been developed as extracellular matrix to regulate the behavior conversion of nerve cell, such as neuronal neurite growth and directional differentiation of neural stem cells, providing a robust driving force for nerve regeneration. This review mainly focused on the biological basis of nerve cells in mechanical transduction. In addition, we also highlighted the effect of the physical cues, including stiffness, mechanical tension, two-dimensional terrain, and electrical conductivity, on neurite outgrowth and differentiation of neural stem cells and predicted their potential application in clinical nerve tissue engineering.

Although the mortality rates of patients suffering from spinal cord injury (SCI) have decreased as the modalities of clinical therapy have been improved, the recovery of motor and sensory functions remains a challenge, ultimately leading to paraplegia or quadriplegia. Recently, neural tissue engineering scaffolds with appropriate physical and biological functions have been extensively developed to promote nerve regeneration and improve motor and sensory functions during SCI therapy. In this work, we summarized the physical support and bioelectrical signal conduction of polymer scaffolds for SCI repair from the aspects of biocompatibility, biodegradation, internal structure, mechanical performance, and conductivity. In addition, the biological functions of the polymer scaffolds were reviewed for the reversal of adverse pathophysiological factors to improve the microenvironments of the injured site and promote endogenous neurogenesis during SCI therapy. Moreover, the future development of these engineered scaffolds for potential clinical applications was predicted.