Department of Orthopedic Diseases, Jinan Military General Hospital (250031) Zhihou Fu, Xintao Qu, Ming Xu, Wenpeng Hui, Xiaochen Liu, Recurrent patellar dislocation is a common clinical disease. There are many specific pathogenic factors for patellar dislocation, but Q angle enlargement and high patella are the pathologic basis, and trauma is the causative factor. Currently, surgical treatment is mostly advocated. The aim of surgical treatment is to reestablish a normal patellar line of force, prevent recurrent patellar dislocation, correct the localized pathoanatomical basis as much as possible and reconstruct the knee-extension device. In this paper, 25 cases of recurrent patellar dislocation were treated with minimally invasive surgery under arthroscopy from January 2005 to December 2008 by loosening the lateral supportive band of the knee joint, tightening the medial supportive band, and shifting the stopping point of the patellar ligament, and the results were good. Fu Zhihou, Department of Orthopedic Diseases, General Hospital of Jinan Military Region Data and Methods I. General information: 25 cases of 44 knees in this group, 8 cases of male, 17 cases of female; 19 cases of bilateral; 26 sides of the left knee, 18 sides of the right knee. Surgical age was 16-46 years old, mean 21.5 years old. The age of patients at first dislocation was 13-25 years, mean 15 years. The mechanism of injury for the first dislocation was trauma in 18 cases. Symptoms were the presence of patellar dislocation for more than 2 times, which resulted in different degrees of swelling, pain, blood accumulation in the joint, and different degrees of limitation of movement. Preoperative examination: 1. Physical examination: 25 patients had positive fear test and patellar tilt test, Q angle: 140-270, mean 17.40±4.50. 2. X-ray examination: 300 positions of knee flexion were taken for knee joint frontal and lateral and patellar axial radiographs, and Blumensaat line and Insall index were measured. 3.CT examination: All patients underwent CT examination of the knee joint, of which 9 patients underwent 320-row CT examination to observe the development of the knee joint and determine the pathological factors of patellar dislocation. Surgical methods: 1, arthroscopic lateral support band release and medial support band tightening, totaling 4 cases and 7 knees; 2, arthroscopic lateral support band release and medial support band tightening at the same time with Roux-Goldthwait type patellar ligament stop internal displacement, totaling 5 cases and 9 knees; 3, arthroscopic lateral support band release and medial support band tightening, totaling 5 cases and 9 knees; 3, arthroscopic lateral support band release and medial support band tightening, totaling 5 cases and 9 knees; 3, arthroscopic lateral support band release and medial support band tightening, totaling 5 cases and 9 knees. support band tightening and Fulkerson type tibial tuberosity internal displacement osteotomy [1], a total of 16 cases and 28 knees. Twelve of these knees underwent a subluxation of the stop at the same time as an internal tibial tuberosity shift to correct the high patella. Results Postoperative follow-up ranged from 12 to 36 months, with an average of 18 months, and no recurrence was seen in any of the 25 patients; Q-angle: 17.40 ± 4.50 preoperatively, 10.60 ± 1.60 postoperatively; Lysholm Knee Function Composite Score of 52.6 ± 6.5 points preoperatively, 92.3 ± 7.5 points postoperatively. All patients had no postoperative complications such as infection, vascular nerve injury, limited joint movement, non-healing osteotomy, rupture of patellar ligament, etc. Six knees had joint hematocrit after surgery, and the symptoms disappeared after treatment such as arthrocentesis and fluid extraction. Discussion Recurrent patellar dislocation usually develops on the basis of knee dysplasia. Numerous factors contribute to patellar dislocation, including abnormal patellar shape, hypoplastic femoral epicondyle, contracture of the iliotibial bundle, laxity of the medial support band, contracture of the lateral support band, increased Q-angle, medial and lateral knee valgus deformity, and high patella. Increased Q angle and high patella are the basis of the pathology, while trauma is the causative factor. Recurrent patellar dislocation often requires surgical treatment, which is aimed at reestablishing a normal patellar line of force, preventing recurrent patellar dislocation, correcting the localized pathoanatomical basis as much as possible and reconstructing the knee-extension device. There are numerous surgical options, which are categorized as release of the tight lateral support band; proximal realignment of the extensor mechanism; distal realignment of the extensor mechanism; proximal and distal realignment of the extensor mechanism; and patellar resection and quadriceps molding repair. The surgical approach should be selected based on the pathologic basis of the dislocation and is often treated with a combination of procedures. Extensive lateral support band release and medial support band tightening are the basic modalities in all combined procedures. The literature reports that arthroscopic lateral support band release combined with medial support band tightening has a high rate of postoperative recurrence and no significant improvement in Q-angle or radiographic measurements. However, there are also reports that arthroscopic lateral support band release combined with medial support band tightening is equivalent to open surgery. Arthroscopy allows thorough examination of articular cartilage damage and intra-articular structural changes, and it is an important step in the surgical treatment of any patellar dislocation, and it is preferred for patients without extensive ligamentous laxity and knee dysplasia. treatment [2]. Recent literature reports that medial support band reconstruction can be anatomically reconstructed with little effect on the knee-extension device, low recurrence rate, and good outcome [3]. In this study, four cases of 7 knees were treated for recurrent patellar dislocation using arthroscopic lateral support band release combined with medial support band tightening, and no cases of recurrence were seen postoperatively. Roux-Goldthwait type patellar ligament stop medial displacement is based on arthroscopic lateral supportive band release combined with medial supportive band tightening, an incision is made at the tibial tuberosity, the patellar ligament is separated longitudinally into two parts, the lateral part is separated from the tibial tuberosity, and the deeper portion of the medial part is pulled medially and sutured and fixed to the goosenecks tendon, in order to change the distal patellar line of force, reduce the Q-angle, and increase the patellar stability.Chavez et al. reported patellar dislocation in 36 knees with an excellent rate of 77.8% objectively evaluated at 16 years of postoperative follow-up [4]. In this study, a total of 5 cases and 9 knees were treated with this procedure, and no recurrence was seen in the postoperative follow-up, and no complications such as patellar ligament rupture were seen. This procedure is less invasive, simple, and effective for recurrent patellar dislocation caused by peripatellar soft tissue imbalance, but poor in cases where the patella is significantly displaced and there is a lesion in the intercondylar recess of the femur. The disadvantage is that it reduces the strength of the patellar tendon and carries the risk of patellar tendon rupture. Fulkerson’s technique of performing tibial tuberosity osteotomy, which is based on arthroscopic lateral knee support band release and medial support band tightening, can help to relieve the pressure on the patellofemoral joint, avoid or delay the wear and tear of the patellofemoral joint, and effectively improve the postoperative symptoms, as well as truly anatomically improve the Q-angle [1,5]. In patients with femoral condylar dysplasia the inward elevation of the tibial tuberosity is more effective due to the reduced resistance of the lateral femoral condyle to patellar dislocation. In this study, 16 cases of 28 knees were treated with this procedure and the Q angle improved significantly after surgery and no complications such as epiphyseal injury or knee reflexion were seen. Preoperative X-ray measurements such as Insall index greater than or equal to 1.2 is diagnosed as high patella, intraoperatively in the tibial tuberosity of the internal displacement at the same time should be downward displacement, otherwise the effect is not good, the distance of downward displacement should be based on the patellar length reconstruction of about 1.2 Insall index is calculated. In this study, the application of arthroscopic lateral support band release and medial support band tightening of the knee joint combined with Roux-Goldthwait type patellar ligament stop internal displacement or Fulkerson type tibial tuberosity osteotomy for the treatment of recurrent patellar dislocations has the advantages of simple operation, less trauma, fewer complications, and good recovery results. Preoperative and intraoperative judgment of the pathologic factors of dislocation, the choice of combined techniques to eliminate the instability factors, and the reduction of the Q-angle are the keys to the success of the operation. References [1] Fulkerson JP, Becker GJ, Meaney JA, et al. Anteromedial tibial tubercle transfer without bone graft. Am J Sport Med, 1990, 18(1):490-97. [2] Ali S , Bhatti A. Arthroscopic proximal realignment of the patella for recurrent instability: report of a new surgical technique with 1 to 7 years of follow -Arthroscopy, 2007, 23(3):305-311. [3] Noyes FR, Albright JC. Reconstruction of the medial patellofemoral ligament with autologous quadriceps tendon. arthroscopy, 2006, 22(8): 9041- 9047. [4] Chavez J, Rodriguez M, Romero J. Current aspect of surgical management of patellar dislocation in the growth period with special reference to Goldthwait surgery. z Orthop Ihre Grenzgeb, 1998, 136(3):30-34. [5] Zhao JZ, He YH, Wang JH. Arthroscopic patellar support band adjustment combined with Fulkerson osteotomy for recurrent patellar dislocation. Chinese Journal of Orthopaedics, 2005, 25(6):326-331.