| 1. An anatomical study for the functional bundles and functional regions of the medial patellofemoral ligamentObjective: The normal trajectory of the patella was maintained by both the bone structure such as patella, femoral block, and, more importantly, the lateral retinaculum and surrounding soft tissue structures. Of which, the medial patellofemoral ligament (MPFL) is the primary structure. Anatomy has described the MPFL as a distinct structure in the second layer of the medial soft tissues above the knee coursing from the medial femoral epicondyle to the supra-medial two-thirds of the patella. However, there have been some debates about the exact location of the femoral attachment. Now, MPFL reconstruction has been the main choice for patellar dislocation, and understanding of the anatomy of MPFL is critical to the success of the MPFL reconstruction. The present study was to explore the anatomical features of the MPFL to build the base to the MPFL reconstruction in clinical practice.Method: Twelve knees (5 left and 7 right) from 7 (5 men and 2 women) fresh-frozen cadavers in the department of anatomy of Hebei Medical University were dissected in the present study. The specimens were frozen at -210C and thawed to room temperature the night prior to dissection. The mean age was 50 years (range from 30 to 65). The skin and subcutaneous tissue of the medial side of the knee were removed, and the distal insertion of the vastus medialis obliquus (VMO) and its muscle belly were entirely exposed. Along the inferior border of the VMO, dissection was performed until the upper margin of MPFL was fully exposed. The soft tissue over the MPFL was blunt dissected and removed, where the VMO, combined with the tendon of adductor magnus (TAM), served as reference to identify and dissect the MPFL. With a forceps under the MPFL, the femoral attachment and patellar insertion were blunt identified and dissected. General feature of the MPFL and its femoral and patellar insertions were observed. All anatomical landmarks were carefully identified and marked. All data were obtained, described, and analyzed in the form of mean±SD. All measurements were taken with a sliding caliper by the same person in order to reduce the interobserver variation. The accuracy of the sliding caliper is 0.1 mm.Results: The MPFL was found in all specimens we dissected. Among all knee specimens, the MPFL was found to locate in the second layer of the medial side of the knee. When the distal part of the VMO was reflected anteriorly along its lower margin, the upper margin of the MPFL was observed to adhere to the deep aspect of the VMO In the present study, the center of the area where fibers of the MPFL originated was carefully identified as the initiation point of the MPFL, which was not located at the adductor tuberosity or the MFE in knee specimens of this dissection. Referring to the MFE, the position of the initiation point was located: the paralleled and perpendicular distance relative to the long axis of femur between it and MFE was 8.90±3.27 and 13.47±3.68 mm, respectively. Along its course, fibers of the MPFL become wider, the width was 13.71±4.03mm at the level of the insertion of the VMO, of 22.28±2.92mm at the patellar insertion. It is as fan-sharp along its trip, forming two relative centered fiber bundles. The lower fiber bundle, named as inferior-straight bundle (ISB), attaches the medial aspect of the patella nearly horizontally, and its length equal to the distance between the femur initiation point and the medial edge of patella was 71.78±5.51 mm. The upper fiber bundle, named as superior-oblique bundle (SOB), also attaches the superior-medial aspect of patella, with some fibers merging into the patellar quadriceps fibers, and its length from the femur initiation point to the superior pole of patella measured was 73.67±5.40 mm. The angle formed by the two fiber bundles was 15.10±2.10. Although the inferior-straight bundle insertion is in the inferior part of the patellar MPFL footprint and the superior-oblique bundle in the superior part, the bundles are not separated completely. This makes the MPFL the intact structure, where its patellar footprint was 22.28±2.92 mm. The total height of patella was 49.73±3.84 mm, and the percentage of the MPFL footprint was calculated to be about 1/2. Closed to the patellar insertion, it adheres to the deep surface of the VMO. Due to the VMO, the MPFL is divided into two functional regions. Closed to the patellar insertion, it is called the combined region, with the VMO overlaied. From the femoral origin, it is defined as the isolated region, without the the VMO overlaied. Anatomically, the MPFL was measured to be 58.8 mm, with the combined and isolated region of 44.72±5.32mm and 25.67±5.03 mm.Conclusion: MPFL as a distinct structure in the second layer of the medial soft tissues above the knee coursing from the medial femoral epicondyle to the supra-medial two-thirds of the patella. Referring to the MFE, the position of the initiation point was located: the paralleled and perpendicular distance relative to the long axis of femur between it and MFE was 8.90±3.27 and 13.47±3.68 mm, respectively. Closed to the patellar insertion, it adheres to the deep surface of the VMO. Due to the VMO, the MPFL is divided into two functional regions. Closed to the patellar insertion, it is called the combined region, with the VMO overlaied. From the femoral origin, it is defined as the isolated region, without the the VMO overlaied. Approximately from the origination, fibers of the MPFL become wider as fan-sharp along its trip, forming two relative centered fiber bundles.The lower fiber bundle, named as inferior-straight bundle (ISB), attaches the medial aspect of the patella nearly horizontally, and its length equal to the distance between the femur initiation point and the medial edge of patella was 71.78±5.51mm. The upper fiber bundle, named as superior-oblique bundle (SOB), also attaches the superior-medial aspect of patella, with some fibers merging into the patellar quadriceps fibers, and its length from the femur initiation point to the superior pole of patella measured was 73.67±5.40 mm. Patellofemoral contact begins with the distal part of the patella at approximately 200 of flexion, and it progresses to the proximal pole of the patella at 900 of flexion.With the flexion of the knee, the VMO starts to contract, the superior-oblique bundle is pulled proximally and appears shorter due to the tension through fibers attached to the VMO. As a result, the superior-oblique bundle with VMO provides the major dynamic soft tissue restraints and pulls the patella medially. When the knee is in flexion of 20-30, the patella slips into the femoral trochlea groove, and the resultant lateral force is resisted by the prominent lateral facet of the femoral trochlea. Therefore, the role of the MPFL with the knee in deep flexion remains unknown. The pressure between the patellofemoral joint might be balanced by the tension of the MPFL. So this finding may provide the theoretical foundation for the anatomical reconstruction of the MPFL and shed lights on the future researchers.2. Clinical treatment the injury of the medical patellofemoral ligament based on the acute injury patternsObjective: Acute patellar dislocation is a relatively common knee injury that occurs most commonly in adolescents. The recommendation for treatment is initially conservative. In spite of the treatment methods, the recurrence rate has been high in general. It has been hypothesized that failure to identify and correct incompetence of the MPFL at the injury site may contribute to recurrence in the treatment to primary dislocation. With the VMO into consideration, we introduced the simple three-part classification of acute MPFL injury patterns: isolated region injury and combined region injury with the meshing point to divide, and the combined injuries. The purpose of the present study was to analyze clinical results of conservative treatment to primary acute patellar dislocation, with comparion between patellar and femoral MPFL injury types categorized by ourselves.Method: To be included in the study, precise diagnosis of acute patellar dislocation was based on the history of a laterally displaced patella and on physical examination. The radiographic examination includes anteroposterior, lateral radiographs of the affected knee. Magnetic resonance imaging (MRI) was routinely acquired to detect potential osteochondral or chondral fragments and to confirm and categorize the injury of the MPFL. MR images were analyzed by two experienced orthopedic surgeons. The MPFL injury patterns were assessed and categorized into three types according to the meshing point of the MPFL and VMO: isolated region injury,combined region injury and combined injury. Combined region injury is defined as the injury from that point to the medial patellar margin, to the femoral origin is called the isolated region injury and the combined injury is the coexistence of the combined region and isolated region injury. To facilitate the study, the combined injury was excluded from the analysis. From January 2003 to December 2009, our department were treated 98 cases of primary dislocation of the patella in patients with a statistical analysis of MRI.Based on the inclusion and exclusion criteria, 85 patients were retrospectively reviewed in the present study. Thirty three patients were with the MPFL combined region injury (Group P) and 52 patients were with the isolated region injury (Group F). For the conservative treatment, atraumatic reduction, aspiration of the hemarthrosis If necessary, arthroscopic procedure was performed. early mobilization and rehabilitation should be initiated including quadriceps isometrics, straight leg raises, and single-plane motion exercises and so on, and the patient should be allowed to progress as tolerated. In the follow up, the patellar stability was evaluated with the apprehension test into three groups as stability, subluxation, and redislocation. In addition, the Kujala patellofemoral score was used for subjective knee function. The 100-mm visual analog scale was used to determine the patient's subjective pain in the affected knee. The statistical analysis was performed with SPSS 13.0 software (SPSS Inc, Chicago, Illinois). Significance was set at P≤.05.Results: Of 98 MRIs, MPFL injury was divided into 3 patterns: combined region injury was in 36 patients; isolated region injury was 56 patients and combined injury six patients. At final follow-up, 2 patients (6.1%) in group P and 11 patients (21.2%) in group F had patellar redislocation (P=0.060). Painful patellar subluxation occurred in 3 patients (9.1%) in group P and in 9 patients (17.3%) in group F (P=0.289). Overall patellar instability was present in 5 of the 33 patients (15.2%) in group P and in 20 of the 52 patients (38.5%) in group F, with statistical difference between the grooups (P=0.022). The mean visual analog scale for combined region and isolated region injury groups were 15.6 points and 28.3 points, respectively (P=0.026). The mean Kujala score was 91.1 points and 82.6 points (P=0.009), with a good or excellent subjective result recorded for 27 of 33 patients (81.8%) in group P, compared with 30 of 52 patients (57.7%) in group F (P=0.021).Conclusion: The MPFL injury patterns were assessed and categorized into three types according to the meshing point of the MPFL and VMO: combined region injury, isolated region injury and combined injury. Combined region injury is defined as the injury from that point to the medial patellar margin, to the femoral origin is called the isolated region injury and the combined injury is the coexistence of the combined region and isolated region injury. Some authors have felt that failure to identify the injury site of MPFL may contribute to recurrence in the treatment to primary dislocation, to speak in further, failure to identify the relationship between the MPFL injury site and the VMO may jeopardize the success of the treatment, as showed in the present comparison between the combined region and isolated region injury patterns: patients with combined region injury of MPFL would achieve lower patellar instability rate (15.2% versus 38.5%) and better subjective function (91.1 versus 82.6). The different anatomical characters of MPFL femoral origin and patellar insertion may make an explaination for these differences. Different injury patterns of MPFL in primary acute patellar dislocation have resulted in different clinical results based on the same conservative procedure. Conservative treatment achieved a lower patellar instability rate and better subjective function for combined region injury of MPFL than that for isolated region injury. In future, the injury pattern of MPFL should be considered to choose the treatment methods for the acute patellar dislocation.3. Clinical study for the anatomical reconstruction of the medial patellofemoral ligamentObjective: The MPFL reconstruction is popular in clinical practice for chronic patellar dislocation. With the anatomy of the medial patellofemoral ligament in-depth research, clinical MPFL reconstruction experienced a non-anatomical reconstruction of the changes to the anatomical reconstruction, single-bundle reconstruction changes to the double-bundle reconstruction, and the combined reconstruction with VMO. The present study aims to compare the clinical results of isolated MPFL reconstruction and those of a combinative reconstruction with vastus medialis advancement, and double-bundles reconstruction, with comparation in the postoperative redislocation rate and knee function.Method: From January 2003 to December 2009, 131 patients with symptomatic chronic patellar dislocation underwent arthroscopically assisted MPFL reconstruction with or without vastus medialis advancement were retrospective analyzed in the present study. According to the surgical procedure, all the patients were divided into three groups: the isolated single-bundle reconstruction, the single-bundle with the vastus medialis advancement and double-bundle reconstruction group. Autologous semitendinosus -gracilis were choosed for grafts, folded from the middle into two shares. Whip stitches are placed in folding end about 2.5 cm, while pullout sutures wrer in the other two ends. The mid-point between medial femoral epicondyle and adductor tubercle and the upper middle 1/3 of the medial margin of patella were initially selected as the femoral and patellar insertion site to check the isometry of graft. In the selected femur point, the bone tunnel was drilled with 7.0-mm in diameter and 25mm-30mm in depth, the suture end was pulled into the blind tunnel through the pullout line and then fixed with a 7.0×23mm bioabsorbable interference screw. Blunt dissection was carried out to create a soft tissue tunnel from the medial border of patella to the medial epicondyle, deep to the medial retinaculum but superficial to the synovium and the free ends of the graft were then pulled through the soft tissue tunnel. Two transverse tunnels were created beneath the prepatellar aponeurosis at supermedial corner and midpoint of medial border of patella to reconstructe the functianal bundles of MPFL: inferior-straight bundle and superior-oblique bundle. With the tension to the ligament, the knee was placed a range of motion and patellar track was monitored under arthroscopy. At 60 degree of knee flexion, whip sutures were performed between the prepatellar aponeurosis and graft to fix the inferior-straight bundle. With the similar motheds, the superior-oblique bundle was sutured at the supermedial corner with the knee at extension. The surgery was with a complement of vastus medialis advancement. In addition, the lower border of vastus medialis obliquus was advanced 5 to 10 mm distally and laterally and sutured on the surface of the reconstructed superior-oblique bundle about 20 mm. During follow up, the apprehension test was conducted and the redislocation was recorded. The patellofemoral joint was evaluated with CT scans and the knee function determined with the Kujala score and with a subjective questionnaire. Statistical analysis was conducted with the SPSS software. A P value of less than 0.05 was considered statistically significant.Results: Between the single-bundle renconstruction group and the combination reconstruction group, 8 patients in Group S (28.6%) and 3 cases (7.3%) in Group C were more than 1.5 cm at the apprehension test, with the hard end, with the significant differences between groups (P=0.042).On CT images, all the index were within the normal range without a statistically significant difference between the two groups. The Kujala scores were 79.9±6.2 and 83.9±6.5, without the significant differences between groups (P=0.074). The excellent and good rate were 67.9% and 87.8%, with the significant differences between groups (P=0.035). As the results between the single and double-bundle reconstruction, 3 cases (7.3%) in Group C were more than 1.5 cm at the apprehension test, with the hard end, with the significant differences between groups (P=0.031). On CT images, all the index were within the normal range without a statistically significant difference between the two groups. The Kujala scores were 83.9±6.5 and 95.9±5.4, with the significant differences between groups (P=0.046). The excellent and good rate were 87.8%and 98.4%, with the significant differences between groups (P=0.024). Conclusion: Patellar dislocation is a common orthopedic clinical disease, with most cases, the medial patellofemoral ligament (MPFL) was found relaxation, torn, or dysfunction in recent years, especially in the cases with the normal development of bone structure. Biomechanical studies have confirmed that MPFL is the primary, also the important soft tissue inhibiting strength for patellar dislocation. Therefore, MPFL is the main surgical choice for the treatment of patellar dislocation, aimed at restoring the normal anatomy and function. With the anatomy of the medial patellofemoral ligament in-depth research, clinical MPFL reconstruction experienced a non-anatomical reconstruction of the changes to the anatomical reconstruction, single-bundle reconstruction changes to the double-bundle reconstruction, and the combined reconstruction with VMO. Although many debates are still on MPFL the reconstruction about the graft, the surgical procedures, the double-bundle anatomical medial patellofemoral ligament reconstructionfor for patellar dislocation, can correct poor patellar track and reduce the subjective symptoms of patients and improve knee function. |
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