| Objective: Due to the complexity of the patella trajectory and regulatory diversity of surrounding soft tissues, patellar dislocation has become a common disease in orthopedics. Its treatment is great challenge for orthopedic surgeons. With the development of research on biomechanics in recent years, it has been found that medial patellofemoral ligament(MPFL) accounts for about 50% to 60% of the effects of limiting patella extraversion and controlling patella trajectory in medial soft tissues. Therefore, the reconstruction of MPFL has become the main operation choice for patellar dislocation. At present, there are various surgery methods for MPFL reconstruction. Double-bundles reconstruction is accepted by more and more scholars in recent years. Double function bundles of MPFL include inferior straight and superior oblique. The latter is cross jointed with vastus medialis oblique(VMO) at the patellar end point. In the early stages of the knee bending, the dynamic function of limiting patella lateral tilting of VMO is far more than 50% of the static function, so reconstruction of VMO should be paid attention to during reconstruction of MPFL. This paper restored the stability of patellar surrounding soft tissue vianatomic double bundle technique for MPFL reconstruction with reconstruction of VMO. And arthroscopy was assisted to explore and observe intra-articular condition, patellar position and patella trajectory, to treat patellar dislocation as well as evaluate the curative effect of surgery treatment, so as to further provide a better surgical method for clinical application.Methods: A retrospective study was performed on 34 cases of patients(34 knees) with patellar dislocation confirmed by physical examination and imaging examination in Joint Surgery of The third Clinical Medical College of Hebei Medical University, all of whom were suffered double bundle technique for MPFL reconstruction from June 2013 to December 2014. 12 cases were male and female were 22 cases, aging from 16 to 40 years old, with an average age of 24. Semitendinosus-gracilis tendons autografts were used for operation, to separately reconstruct double bundles of MPFL. Lateral femoral end point was selected as the middle point of the highest points of adductor nodules and medial femoral condyle, while two patellar-lateral end points selected were the middle point of the medial margin of patella and the point near the upper pole of patella. Femoral-lateral fixation was that along the needle, a 7mm(diameter) drill was drilling to form a bony tunnel of 3cm; the reflex end of the tendon was led into the tunnel and fixed by absorbable extrusion screw with a diameter of 7×23mm. To fix the patella end has the modified semi-tunnel bone bridge fixed and the suture anchors fixed Tendinous tissue of vastus medialis oblique head at medial patellar attachment points was cut off. It was pulled down and inside to make it sutured with superior oblique of patellofemoral ligament at a location near the patellar medial end point. Arthroscopy and manual muscle test were used at last to find the patella trajectory in the femoral trochlea and the dynamic corresponding relationship of patellofemoral joint. Especially in the early days of the knee bending, it can ensure patellar smoothly into the femoral trochlea. Brace was used for postoperative support and protection. The patients were asked for regular rehabilitation exercise. Patients were followed up and recorded for postoperative complications and number of redislocation. Physical examination was mainly for the stability of the patella and patellar apprehension test. Postoperative CT measurement was used for patellar lateral shift rate(PLSR) and patella tilting angle(PTA), etc. at 20° of knee bending, and rpatellar location was observed. Kujala score system and Lysholm score system for knee function were used to evaluate the function of knee joint. SPSS 13.0(Chicago, III) was used for statistics. Mean values was compared by t test between groups. P<0.05 referred statistically significant differences.Results: All the patients had primary healing(Grade A). Infection, complications related to nonunion, or formation of deep venous thrombosis was not observed. All the patients were followed up. During the follow-up, all of the patients had negative results of patellar tilting test and patellar apprehension test. No subluxation, redislocation or fractures occurred. Postoperative CT measurements showed congruance angle(CA) was reduced from 20.20±3.38 to 10.17±2.33; patella tilting angle(PTA) was reduced from 18.94±2.24 to 10.93±1.51; patellar lateral shift rate(PLSR) was reduced from 19.42±1.28 to 9.82±1.64; And for knee functional scores, Kujala score was increased from 59.74±3.68 to 91.19±3.11; while Lysholm score was increased from 59.73±4.79 to 92.60±1.94; with statistical significance(P<0.05).Conclusions: Anatomic double bundle technique for MPFL reconstruction combined with reconstruction of VMO can obviously improve patella trajectory in treatment of patellar dislocation. And it can dynamically observe the condition inside the joint and the matching of patellofemoral joint under arthroscopy, so as to improve the function of the knee joint. But since the mechanics mechanism of patellar dislocation is very complicated, which involves many factors, long-term clinical follow-up with large sample size is still needed to observe the clinical effects. |
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