| Background:Chondromalacia patellae (CP) is knee cartilage injury disease characterized by patellofemoral joint cartilage softening and degeneration due to a variety of reasons, which is one of common causes of anterior knee pain. In 1906, Budinger first discovered the pathological damage of patellar cartilage surface. Later the pathological change has attracted wide attention of scholars and has been studied for further. In 1924, Koenig first named the pathological state as chondromalacia patella. In 1961, Outerbridge divided into the CP pathological process for four periods, in his view, grade I is softening and swelling of the patellar cartilage surface. Grade II is fragmentation and fissuring in an area half an inch or less in diameter, grade III is fragmentation and fissuring in an area half an inch or more in diameter and grade IV is erosion of cartilage down to bone. In 1970, Bentley further improved the stage, he thought, grade I is a localised softening, swelling or fibrillation of the articular cartilage in an area of 0.5 cm or less. Grade II is fragmentation and fissuring in an area 1.3cm or less in diameter. Grade III is fragmentation and fissuring in an area of more than 1.3cm in diameter. Grade IV is erosion of cartilage down to bone. In 2001, Ye Qibin etc also divided into CP pathological change process for 4 stages, they thought, grade Ⅰ and Ⅱ is patellofemoral joint cartilage edema, softening and fragmentation. Ⅲ-Ⅳ stage is cartilage loss, subchondral bone sclerosis and bare. At the same time Ye Qibin etc considered that the patellar cartilage of early (Ⅰ and Ⅱ) stage still has the capacity for repairing, but in the late stage (Ⅲ-Ⅳ ), CP has evolved into the patellofemoral arthritis, at this time, patellar cartilage has no real ability to repair.CP has a high incidence rate, in 1961, Outbridge researched 196 cases of medial meniscectomy patients, as a result, the number of patella of healthy articular cartilage almost equal to the number of patella of articular cartilage suffered from the pathological change. Therefore, he believed that the actually prevalence of CP is higher than commonly believed prevalence rate, due to CP dose not necessarily has clinical symptoms, so many CP patients will not come to the outpatient clinic, resulting in the lower incidence of CP we usually think of. In 1998, Guo Kaijin surveyed 2743 members of CP prevalence of general population. The results showed that the CP in general population has a high prevalence rate of 36.2%, female prevalence rate was higher than that of male. After this, Zhang Hui made a prevalence survey of college students, Kong Xiangqing made a survey of college students in physical education department of CP prevalence. They also confirmed the high prevalence of CP.The cause of chondromalacia has not been cleared, the majority of foreign scholars agreed that trauma is one of causes of chondromalacia. In domestic literature, trauma, patellar instability, increased pressure and dissolution of patellar cartilage, chondrodystrophy, autoimmune, patellar pressure effects are associated with the pathogenesis of CP. As a central role in the pathogenesis of CP, there have been many documents in studying patellar instability. In 1994, Dejour thought trochlear dysplasia, patella alta, femoral muscle dysplasia and tibial tubercle to the trochlear groove distance anomaly is important in the pathogenesis of patellar instability. Wu Yujin believed the patellar instability mainly refers to the patella alta, patella baja, patellar tilt and patellar subluxation.When patellar tilt or patellar subluxation, the pressure of patellofemoral articular cartilage surface has an uneven distribution, the pressure of patellar lateral surface is excessive concentration, while inner side surface has no obvious stress, the pressure uneven distribution of patellofemoral articular cartilage leads to the patellofemoral articular cartilage wear and softening. When femoral trochlear dysplasia, patellofemoral anatomical is disorder, trochlear has a shallow and flat groove, the patellar movement limited by the medial and lateral femoral condyle is weakened, easily leads to the patellar tilt and subluxation, and easily to cause cartilage wear and softening. Su Peng etc, Lu Wei etc had studied the correlation between the position of the patella, patellar tilt patellar subluxation and CP respectively.They considered that the position of the patella, patellar tilt patellar subluxation and CP has a significantly correlation, however,when refers to the correlation of trochlear dysplasia and CP, Chinese population samples are lack.There are many methods to treat CP, including massage, physical therapy, acupuncture therapy and warm needling and therapy combined with rehabilitation training, joint cavity injection, arthroscopic joint cleaning operation, autologous chondrocyte implantation and many other treatment methods. However, so far, there are no absolutely effective patterns in the treatment of CP.Sodium hyaluronate (SH) is the sodium salt forms of hyaluronic acid (HA), HA is a main component of articular cartilage and synovial fluid and is a glycosaminoglycan composed of repeating disaccharide units of β-D-gluconic acid and P-D-N-amino glucose and is high molecular weight (6500-10900Kda) physiological active substances of visco elastic properties. As a kind of viscoelastic supplements, HA has the effect of covering with articular cartilage surface and protecting articular cartilage, shielding pain receptors, inhibiting the expression of inflammatory factor, alleviating the inflammation of synovium, relieving joint pain, joint lubrication, improving pathological synovial fluid, promoting the synthesis of endogenous HA, delaying the cartilage injury, promoting cartilage repair and so on.Therefore, HA should have a good treatment effect for the cartilage injury disease like CP. A large number of clinical studies of China have confirmed the good efficacy of HA in the treatment of CP. However, a review of the literature revealed, the majority of authors does not explain the site selection of HA, they are more willing to rely on the personal experience and proficiency in choosing the injection site. The early research of us suggested that choosing the injection site is actually a key step in HA injection, the commonly used 2.5 ml of HA can not fully distributes in the joint cavity and covers all the articular cartilage surface. In early performed 32 cases of cadaveric study, we found that, when the knee joint size is relatively large, the distributed of drugs is mainly in the patellofemoral joint injected by the subpatellar injection site, however, the distributed of drugs is mainly in the tibiofemoral joint injected by the joint line injection site. In order to achieve the maximum coverage of lesion cartilage, we should choose the injection site according to the diesease. At the same time, we have a further doubt that differences in clinical injection site selection can lead to differences in drug distribution, then wheather it will has a further influence in clinical efficacy and how the effect of the best injection site? This is the direction that we need to research later.Section I Correlation between Patellofemoral Morphology and Cbondromalacia PatellaeObjective To measure the morphological parameters of patellofemoral joint on MRI and analyze the etiological correlation between patellofemoral morphology and chondromalacia patellae (CP).Methods 371 adult patients undergoing MRI examination were enrolled and those diagnosed with CP were included in the CP group (n=124) and others in the control group (n=247). Prevalence rates of CP were recalculated and grouped according to gender. The lateral patellofemoral angle, sulcus angle, trochlear depth and lateral trochlear inclination angle were measured in the MRI images on axial slices. The CP group were further divided into a mild and severe CP subgroup according to the degree of cartilage damage. The difference of patellofemoral morphology parameters between CP group and control group, CP group (mild) and CP group (severe) were compared and the relationships between patella tilt, trochlear dysplasia and CP were further analyzed.Results The prevalence rate of CP was 33.42%, of which women was 49.35% and men was 22.12%. CP group and control group were significant differences in the lateral patellofemoral angle (P=0.00), sulcus angle (P=0.00), trochlear depth (P= 0.00) and lateral trochlear inclination angle (P=0.02). However, there were no significant differences between patients with mild CP group and severe CP group in the lateral patellofemoral angle, sulcus angle, trochlear depth and lateral trochlear inclination angle (all P>0.25). Considered gender or not, patellar tilt and trochlear dysplasia were significant correlated with chondromalacia patellae (P=0.00)Conclusion Patellar tilt and trochlear dysplasia are significantly correlated with CP but not the degree of CP.Section Ⅱ Sodium hyaluronate in the treatment of Chondromalacia Patellae:a one-year prospective clinical studyObjective To observe the clinical effect of injecting sodium hyaluronate in the treatment of Chondromalacia Patellae through subpatellar route.Methods 88 cases were diagnosed with CP(n=88),CP patients were further grouped according to their imaging features.50 cases whose imaging changes were early CP were classified as CP group,38 cases whose imaging changes were late CP were classified as patellofemoral arthritis group. Two groups were both treated with SH injection through subpatellar route,1 times/w, continuous medication 5w as a course of treatment. The outcome measures included primary outcomes:WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) score and Lequesne index score. The secondary outcomes:walk time with 30m, up the stairs and down the stairs time. We followed-up patients before treatment and after treatment of 4 weeks,12 weeks,26 weeks and 52 weeks respectively and recorded each time point of the WOMAC score and Lequesne index score. We also recorded the walk time with 30m, up the stairs and down the stairs time before treatment and after treatment of 1w,2w,3w,4w. The differences of the study results of two groups were statistical analyzed.Results The WOMAC score and Lequesne index score of two groups after treatment of 4w,12w,26w,52w compared with before treatment were significantly decreased (p<0.01). There was no statistical difference between two groups of WOMAC score and Lequesne index score before treatment and after treatment of 4w, 12w (p>0.05). However, patellofemoral arthritis group of WOMAC score and Lequesne index score was significantly higher than those of CP group after treatment of 26w,52w (p<0.05). There was no statistical difference between two groups of the walk time with 30m, up the stairs and down the stairs time before treatment and after treatment of 1w,2w,3w,4w(p>0.05).Conclusion The effect of using subpatellar route intra-articular injection of sodium hyaluronate in the treatment of CP was significant, the effect of early CP was sustained to post-treatment 52w, late CP-patellofemoral arthritis appear effect of recrudescence when treated for 26w and 52w, its clinical efficacy lower than early CP group at post-treatment 26w and 52w. |
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