Early Continuous Passive Motion and Needle-Knife Therapy Alleviate Knee Motor Dysfunction Effects After Internal Fixation of TPFs

Posttraumatic osteoarthritis (PTOA) is a common complication secondary to tibial plateau fractures (TPFs) after internal fixation. Early continuous passive motion (CPM) and needle-knife therapy are both alternative medicine treatments that have been beneficial to PTOA. CPM and needle-knife therapy are commonly applied separately in the treatment of orthopedic diseases and soft tissue injuries, but they both have limitations. In this study, we combined CPM and needleknife therapy to observe its efficacy on PTOA caused by postoperative TPFs and its possible mechanisms. A rabbit model of TPFs after internal fixation was established by surgical method. Rabbits were randomly divided into five groups: Normal control (NC) group, Sedentary (SED) group, CPM group, Needle-knife group, CPM + Needle-knife group. Range of motion (ROM), knee diameter and medial cartilaginous surface of the tibial plateau were observed after 4 weeks of treatment. Levels of inflammatory cytokines in the supernatants from knee joint fluid, including interleukin (IL)-1 beta, IL-6, and tumor necrosis factor (TNF)-alpha, were determined by enzyme-linked immunosorbent assay (ELISA). The gross view of ligament tissues was detected by histomorphology, including Hematoxylin and Eosin (H&E) staining and Masson's trichrome staining. Other than that, the protein expression of matrix metalloproteinase (MMP)-13 and tissue inhibitors of metalloproteinase (TIMP)- 1 were evaluated by immunohistochemical staining, respectively. Finally, the apoptosis of ligament cells was assessed through DAPI and TUNEL assay. Our data showed that ROM was reduced while knee diameter was increased in the SED group, but they were relieved by CPM and needle-knife-either singly or in combination treatment. CPM and needle-knife therapy also improved the effect of TPFs on other parameters, including the medial cartilaginous surface of the tibial plateau improvement, MMP-13 and TIMP-1 expression in the medial collateral ligament (MCL), and lateral collateral ligament (LCL), knee joint fluid IL-1 beta, IL-6, and TNF-alpha levels, and condition of ligament cells apoptosis. Our findings suggested that early CPM plus needle-knife therapy might be a useful and promising therapeutic method for PTOA.