OBJECTIVE: To investigate the impact of bone mass and volume of low-density zones beneath the tibial plateau on the maximum von Mises stresses experienced by the cartilage and meniscus in the knee joint. METHODS: The study included one healthy adult volunteer, from whom CT scans were obtained, and one patient diagnosed with knee osteoarthrisis (KOA), for whom X-ray films were acquired. A static model of the knee joint featuring a low-density zone was established based on a normal knee model. In the finite element analysis, axial loads of 1 000 N and 1 800 N were applied to the weight-bearing region of the upper surface of the femoral head for model validation and subsequent finite element studies, respectively. The maximum von Mises stresses in the femoral cartilage, as well as the medial and lateral tibial cartilage and menisci, were observed, and the stress percentage of the medial and lateral components were concurrently analyzed. Additionally, HE staining, as well as alkaline magenta staining, were performed on the pathological specimens of patients with KOA in various low-density regions. RESULTS: The results of model validation indicated that the model was consistent with normal anatomical structures and correlated with previous calculations documented in the literature. Static analysis revealed that the maximum von Mises stress in the medial component of the normal knee was the lowest and increased with the advancement of the hypointensity zone. In contrast, the lateral component exhibited an opposing trend, with the maximum von Mises stress in the lateral component being the highest and decreasing as the hypointensity zone progressed. Additionally, the medial component experienced an increasing proportion of stress within the overall knee joint. HE staining demonstrated that the chondrocyte layer progressively deteriorated and may even disappear as the hypointensity zone expanded. Furthermore, alkaline magenta staining indicated that the severity of microfractures in the trabecular bone increased concurrently with the expansion of the hypointensity zone. CONCLUSION The presence of subtalar plateau low-density zone may aggravate joint degeneration. In clinical practice, it is necessary to pay attention to the changes in the subtalar plateau low-density zone and actively take effective measures to strengthen the bone status of the subtalar plateau low-density zone and restore the complete biomechanical function of the knee joint, in order to slow down or reverse the progression of osteoarthritis.
Humans ; Finite Element Analysis ; Knee Joint/physiology* ; Tibia/anatomy & histology* ; Cartilage, Articular/physiology* ; Menisci, Tibial/physiopathology* ; Tomography, X-Ray Computed ; Osteoarthritis, Knee/diagnostic imaging* ; Weight-Bearing ; Bone Density ; Adult ; Stress, Mechanical ; Male ; Middle Aged ; Biomechanical Phenomena ; Female

OBJECTIVE: To review the research progress on the lower limb biomechanical characteristics of patients with discoid lateral meniscus (DLM) injury after surgery. METHODS: By searching relevant domestic and international research literature on DLM, the postoperative characteristics of knee joint movement biomechanics, tibiofemoral joint stress distribution, lower extremity force line, and patellofemoral joint changes in patients with DLM injury were summarized. RESULTS: Surgical treatment can lead to varying degrees of changes in the lower limb biomechanical characteristics of patients with DLM injury. Specifically, the kinematic biomechanics of the knee joint can significantly improve, but there are still problems such as extension deficits in the affected knee joint. The peak stress of the tibiofemoral joint decreases with the increase of the residual meniscus volume, and the degree of change is closely related to the residual meniscus volume. Preserving a larger volume of the meniscus, especially the anterior horn volume, helps to reduce stress concentration. The lower extremity force line will deviate outward after surgery, and the more meniscus is removed during surgery, the greater the change in the lower extremity force line after surgery. There are conditions such as cartilage degeneration, position and angle changes in the patellofemoral joint after surgery. CONCLUSION The changes in the lower limb biomechanical characteristics after DLM injury are closely related to the choice of surgical methods and rehabilitation programs. However, the mechanisms of biomechanical changes in multiple lower limb joints and individual differences still need to be further studied and clarified.
Humans ; Biomechanical Phenomena ; Tibial Meniscus Injuries/physiopathology* ; Menisci, Tibial/physiopathology* ; Knee Joint/surgery* ; Lower Extremity/physiopathology* ; Patellofemoral Joint/physiopathology* ; Range of Motion, Articular ; Knee Injuries/physiopathology*

OBJECTIVETo investigate clinical effects of arthroscopy in the treatment of medial meniscal cyst.

METHODSFrom June 2011 to January 2013, 7 patients with medial meniscal cyst were treated with arthroscopy. There were 3 males and 4 females,ranging in age from 27 to 63 years old,with a mean age of (43.93±2.10) years old. The cysts have been discovered for 3 to 30 months,with a mean time of (10.6±1.3) months. All the patients complained of knee pain,especially in the medial joint gap. The Pisani sign, Caklin sign and medial McMurray sign were all positive. Preoperative MRI examination confirmed the diagnosis. Lysholm score changes and clinical efficacy were observed through a six-month follow-up.

RESULTSThe postoperative Lysholm scores were all significantly higher than the preoperative scores. According to Sarimo standard, 6 patients got an excellent result, and 1 good.

CONCLUSIONArthroscopic treatment of medial meniscal cyst has replaced the traditional method, which could retain the normal meniscus as much as possible and repair the meniscus injury simultaneously, as well as get a good curative effect and a good recovery of knee function. This method is worthy of clinical application.

Adult ; Arthroscopy ; methods ; Cysts ; physiopathology ; surgery ; Female ; Humans ; Male ; Menisci, Tibial ; physiopathology ; surgery ; Middle Aged

OBJECTIVETo study the results of arthroscopic partial meniscectomy for medial meniscal tear in late middle-aged adults.

METHODSFrom October 2010 to October 2012,49 patients meeting inclusion criteria were treated with arthroscopic partial meniscectomy for medial meniscal tear. There were 31 males and 18 females,with an average age of (55.3±2.8) years old. There were 22 left knees and 27 right knees. The average flexion angle was (116.01±12.03)°. The pre-operative HSS Knee Score was 48.73±8.43, and the Lysholm score was 63.95±5.45. The patients were followed up and evaluated. All the patients received a standard surgery, in which the torn tissue was removed, and the anterior part of the meniscus was left in situ.

RESULTSAll the surgeries were successful with no serious complications. All the patients were followed up,and the duration ranged from 12 to 36 months. All the patients had 5 degrees of muscle strength. The average flexion angle was (136.77±18.56)°. There was significant difference between the two angles before operation and after operation. The pre-operative HSS Knee Score was 90.17±4.10, and the Lysholm score was 87.84±5.16. Statistically, the difference between preoperative score and the postoperative score was significant.

CONCLUSIONArthroscopic partial meniscectomy is a good option for medial meniscal tear in late middle-aged adults. Operative indication is crucial and the excellent surgical technique is also critical for the good clinical outcome. All the patients could get good clinical results, although there are some patients with motion restrictions in the early stage after operation.

Arthroscopy ; methods ; Female ; Humans ; Knee Injuries ; surgery ; Male ; Menisci, Tibial ; physiopathology ; surgery ; Middle Aged ; Tibial Meniscus Injuries

OBJECTIVETo study the clinical effects of menisci reformation and repair for the treatment of discoid meniscus injuries and to explore the operation methods.

METHODSFrom Jun. 2005 to Dem. 2009, 28 patients underwent arthroscopic menisci reformation and repair for discoid meniscus, including 23 males and 5 females, ranging in age from 6 to 42 years, with an average of 32 years. The nature of meniscus and the type and range of tear were judged under arthroscope. The menisci reformation and repair were used to treat discoid meniscus tear at the edge. After the operation, the brace was used for 8 weeks, and heavy exercise should be avoided for 6 months. The Lysholm score was adopted to evaluate therapeutic effects.

RESULTSAll the patients were followed up ranging from 3 to 36 months, averaged 8 months. The preoperative Lysholm scores ranged from 62 to 74, with a mean of (67.23 +/- 5.24), and the postoperative Lysholm scores ranged from 80 to 96, with a mean of (87.24 +/- 5.26). There was no occurrence of re-tear or re-operation due to symptom recurrence.

CONCLUSIONThe menisci reformation and repair has better clinical effects on the treatment of discoid meniscus tear and can be regarded as one of the operational options.

Adolescent ; Adult ; Arthroscopy ; methods ; Child ; Female ; Follow-Up Studies ; Humans ; Knee Joint ; physiopathology ; Magnetic Resonance Imaging ; Male ; Menisci, Tibial ; surgery ; Tibial Meniscus Injuries ; Young Adult