Objective To investigate the effectiveness of reconstructing medial patellofemoral l igament with hamstring tendon autografts for the treatment of recurrent patellar dislocation under arthroscopy. Methods Between January 2005 and January 2010, 22 cases of recurrent patellar dislocation were treated by lateral retinacular release and reconstructionof the medial patellofemoral ligament with hamstring tendon autografts under arthroscopy. There were 5 males and 17 females, aged 15-19 years (mean, 17.3 years). The average number of dislocation was 4 (range, 3-8). The main cl inical symptoms were pain and swell ing of knee joint, weakness in the leg, and limited range of motion (ROM). The patellar tilt test, pressing pain of patellofemoral ligament insertion, and apprehension sign showed positive results. According to International Knee Documentation Committee (IKDC) scoring criteria, the subjective IKDC score was 36.7 ± 4.7, and the Lysholm score was 69.3 ± 3.8. X-ray films showed that the patella inclined outwards. Results All incisions healed by first intention. Twenty-two cases were followed up 18-49 months (mean, 34 months). Pain and swelling of knee joint and weakness were improved obviously. No recurrence was found during follow-up. The ROM of knee in flexion and extension was improved when compared with preoperative ROM. The subjective IKDC score was 92.4 ± 5.3 and the Lysholm knee score was 91.7 ± 5.2, showing significant differences when compared with preoperative scores (P lt; 0.05). Conclusion Reconstruction of the medial patellofemoral ligament with hamstring tendon autografts under arthroscopy is an effective method to treat recurrent patellar dislocation.
Objective To explore the effectiveness of arthroscopic medial retinaculum pl ication (MRP) for recurrent patellar dislocation in adolescents. Methods Between March 2000 and October 2007, 30 adolescent patients with recurrent patellar dislocation underwent arthroscopic MRP, and 28 of them (12 left knees and 16 right knees) completed thefinal follow-up and were enrolled. There were 5 males and 23 females with an average age of 14.7 years (range, 12-19 years). The dislocation duration was 4 to 39 months with an average of 18.8 months. All patients experienced 2-4 episodes of dislocation. Before operation, all the patients showed positive apprehension test; the degree of lateral patellar translation was (2.9 ± 0.7)° and there was no hardness termination in lateral translation. The International Knee Documentation Committee (IKDC), Lysholm, Kujala, and Tegner scores were 47.7 ± 3.7, 52.6 ± 4.9, 66.7 ± 5.9, and 3.1 ± 1.3, respectively. All patients underwent arthroscopic MRP procedure. Results All incisions healed by first intention without compl ication. All the patients were followed up 2-7 years (4.8 years on average). During the follow-up, more and more patients showed positive apprehension test, and at 24 months of follow-up, 12 patients showed positive apprehension test; less and less patients had hardness termination in lateral translation, only 3 patients at 24 months of follow-up; the degree of lateral patellar translation increased, (2.3 ± 1.1)° at 24 months of follow-up. There were significant differences in positive apprehension test and hardness termination between preoperation and 24 months of follow-up (P lt; 0.05). Moreover, 6 patients suffered from redislocation, and 23 patients experienced patella instabil ity. The IKDC, Lysholm, Kujala, and Tegner scores at 24 months of follow-up were 62.5 ± 6.2, 70.7 ± 5.1, 76.6 ± 4.8, and 3.9 ± 0.7, respectively, showing significant differences when compared with preoperative scores (P lt; 0.05). CT examination showed that the congruence angle, lateral patellar angle, and patellar tilt angle were recovered to normal level after operation immediately, however, the final patellar position at 24 months of follow-up was not significantly betterthan that before surgery (P gt; 0.05). There was significant difference in the lateral patellar displacement between preoperation and 24 months of follow-up (P lt; 0.05). Conclusion Arthroscopic MRP is not rel iable for maintaining the corrected position of the patella for recurrent patellar dislocation in adolescents, though functional improvements are significant.
Objective To investigate the procedure and effectiveness of medial patellofemoral l igament (MPFL) reconstruction for the treatment of recurrent patellar dislocation. Methods Between June 2005 and September 2007, 29 patients with recurrent patellar dislocation underwent MPFL reconstruction with allograft semitendinosus or allograft anterior tibial is tendon. There were 6 males and 23 females with an average age of 20.3 years (range, 13-45 years). The patients sufferedfrom 2-10 times patellar dislocation preoperatively. The average time between last dislocation and surgery was 43.9 months (range, 1-144 months). CT scan was performed to measure the tibial tuberosity-trochlear groove distance (TT-TG). The femoral tunnel was made at the origin of MPFL insertion, just inferior to the medial epicondyle. The double L-shape patellar tunnels were made on the medial rim of patella with 4.5 mm in diameter. The loop side of the graft was fixed with a bioabsorbable interference screw in the femoral tunnel both ends of the graft. For the TT-TG was more than 20 mm, a modified Elmsl ie-Trillat osteotomy was performed to correct the distal al ignment of patella. The arthroscopic examination was also performed for loosebody and lateral retinacular release. Results Twenty-seven patients were followed up 45.5 months on average (range, 40-67 months). No recurrent dislocation or subdislocation occurred. All the patients showed negative apprehension test at 0° and 30° flexions of knee. The range of motion of knee restored normal 1 year after operation. The Kujala score was improved from 72.03 ± 17.38 preoperatively to 94.10 ± 7.59 postoperatively, and Lysholm score was improved from 72.65 ± 14.70 to 95.44 ± 6.25, both showing significant differences (P lt; 0.05). The Tegner score was decreased from 5.25 ± 1.83 preoperatively to 4.33 ± 1.00 postoperatively, showing no significant difference (t=1.302, P=0.213). In patients whose TT-TG was more than 20 mm, TTTG was decreased from (23.38 ± 3.70) mm to (16.88 ± 5.92) mm at last follow-up, showing significant difference (t=2.822,P=0.026). Conclusion The technique of MPFL reconstruction is an effective surgical procedure for the treatment of recurrent patellar dislocation, which can improve the patella stabil ity and knee function.
ObjectiveTo investigate the clinical significance of Q-angle measuring under different conditions in female recurrent patellar dislocation female patients. MethodsBetween August 2012 and March 2013, 10 female patients (11 knees) with recurrent patellar dislocation were collected as trial group; 20 female patients (20 knees) with simple meniscus injury were collected as control group at the same time. Q-angle was measured in extension, 30° flexion, 30° flexion with manual correction, and surgical correction in the trial group, and only in extension and 30° flexion in the control group. Then the difference value of Q-angle between extension and 30° flexion (Q-angle in extension subtracts Q-angle in 30 flexion) were calculated. Independent sample t-test was used to analyze Q-angle degrees in extension, 30° flexion, and the changed degrees of 2 groups. The Q-angle between manual correction and surgical correction of the trial group was analyzed by paired t-test. ResultsThe Q-angle in extension, Q-angle in 30° flexion, and difference value of Q-angle between extension and 30° flexion were (17.2±3.6), (14.3±3.0), and (2.9±1.9)° in the trial group and were (15.2±3.4), (14.4±3.5), and (0.8±1.7)° in the control group. No significant difference was found in Q-angle of extension or Q-angle of 30° flexion between 2 groups (P>0.05), but the difference value of Q-angle between extension and 30° flexion in the trial group was significantly larger than that in the control group (t=3.253, P=0.003). The Q-angle in 30° flexion with manual correction and surgical correction in the trial group was (19.8±3.4)° and (18.9±3.8)° respectively, showing no significant difference (t=2.193, P=0.053). ConclusionWhen a female patient's Q-angle in 30° flexion knee changes obviously compared with Q-angle in extension position, recurrent patellar dislocation should be considered. For female patients with recurrent patellar dislocation, the preoperative Q-angle in 30° flexion with manual correction should be measured, which can help increasing the accuracy of evaluation whether rearrangement should be performed.
ObjectiveTo introduce and analyze the role of tibial tubercle internal rotation to treat recurrent patellar dislocation associated with trochlear dysplasia. MethodsBetween February 2007 and April 2011, 28 patients with recurrent patellar dislocation underwent tibial tubercle translocation through medial transfer, rotation and elevation of the tibial tuberosity and the medial patellofemoral ligament (MPFL) reconstruction. There were 4 males and 24 females with an average age of 21.8 years (range, 17-28 years). The disease duration ranged from 6 months to 8 years (mean, 4 years). The patients suffered from 3-10 times patellar dislocation. The result of apprehension test was positive; Lysholm score was (51.64±3.79); Kujala score was (56.89±3.79). According to Dejour classification, 11 cases were rated as type B, 14 cases as type C, and 3 cases as type D; the tibial tuberosity-trocholear distance (TT-TG) was (20.53±2.58) mm; and the patellar tilt angle (PTA) was (29.34±2.54)°. ResultsPrimary healing of incision was obtained in the others except 1 case of mild infection. Twenty-seven patients were followed up 41.8 months on average (range, 27-74 months). No recurrent dislocation was found, and the result of apprehension test was negative. The knee range of motion restored to normal totally. The postoperative Kujala score and Lysholm score were significantly improved to 88.97±3.06 and 88.95±2.98 (t=-42.005, P=0.000; t=-43.122, P=0.000) respectively. TT-TG and PTA restored to normal[(11.77±2.24) mm and (7.99±2.57)°], showing significant differences when compared with preoperative ones(t=13.032, P=0.000; t=29.533, P=0.000). ConclusionThe technique of tibial tubercle translocation and MPFL reconstruction is an effective surgical procedure for the treatment of recurrent patellar dislocation associated with trochlear dysplasia. Especially, tibial tubercle internal rotation can improve the patella stability and knee function.
ObjectiveTo explore the clinical effects of combined operation involving tibial tubercle distalization for the recurrent patellar dislocation with patella alta.MethodsBetween April 2010 and May 2016, 14 cases of recurrent patellar dislocation with patella alta were treated with combined operation involving tibial tubercle distalization. There were 5 males and 9 females with an average age of 18.5 years (range, 13-26 years). The left knee was involved in 9 cases and the right knee in 5 cases. The patella had dislocated 3.3 times on average (range, 2-5 times). The interval between the first dislocation and admission was 19.7 months on average (range, 4-60 months), and the main symptoms were knee pain and limited knee movement. Preoperative X-ray films, CT, and MRI examinations of knee joint showed that the epiphyseal plate closed in all patients. Of all patients, 3 patients had avulsion fracture of the inner edge of patella, and 2 patients had free body in articular cavity. The tibial tuberosity-trochlear groove (TT-TG) distance, patellar-trochlear-groove distance, Caton-Deschamps index, knee range of motion (ROM), Lysholm score, International Knee Documentation Committee (IKDC) score, Kujala score, and Tegner score were compared pre- and post-operation.ResultsAll patients had primary wound healing. All patients were followed up 24-72 months with an average of 34.6 months. X-ray film and CT examination showed that the patellar dislocation was corrected and the osteotomy of the tibial tubercle healed with an average healing time of 3.8 months (range, 3-5 month). At 1 day and 1 year after operation, the TT-TG distance, patellar-trochlear-groove distance, and Caton-Deschamps index showed significant differences when compared with preoperative values (P<0.05), but there was no significant difference between 1 day and 1 year after operation (P>0.05). At the 1 year and 2 years after operation, the knee ROM, Lysholm score, IKDC score, Kujala score, and Tegner score showed significant differences when compared with preoperative values (P<0.05), and there was no significant difference between the 1 year and 2 years after operation (P>0.05).Conclusion Combined operation involving tibial tubercle distalization is a safe and reliable method, which has satisfactory short-term effectiveness for the recurrent patellar dislocation with patella alta.
ObjectiveTo investigate the short-term effectiveness of derotational distal femoral osteotomy (DDFO) combined with medial patellofemoral ligament (MPFL) reconstruction in treatment of recurrent patellar dislocation with excessive femoral anteversion angle (FAA≥30°). MethodsBetween June 2017 and August 2019, 17 patients with recurrent patellar dislocation with FAA≥30° were treated with DDFO and MPFL reconstruction. There were 5 males and 12 females, aged 14-22 years, with an average of 17.7 years. The patella dislocated for 2 to 8 times (mean, 3.6 times). The disease duration was 2-7 years (mean, 4.6 years). The patellar apprehension tests were positive. Preoperative pain visual analogue scale (VAS) score, Lysholm score, Tegner score, and Kujala score were 4.2±1.1, 47.8±8.1, 3.6±1.1, and 56.8±5.7, respectively. FAA, mechanical lateral distal femoral angle (mLDFA), lateral patella displacement (LPD), tibial tuberosity-trochlear groove distance (TT-TG) were (34.9±3.4)°, (85.8±3.0)°, (13.7±3.8) mm, and (23.1±2.1) mm, respectively. ResultsAll incisions healed by first intention, and there was no complications such as knee stiffness, infection, and re-dislocation of the patella. All patients were followed up 13-25 months, with an average of 17.7 months. The imaging review showed that 1 case of osteotomy did not union, and achieved satisfactory results after the secondary revision and strengthening fixation; the osteotomies of other patients healed completely after 3 to 4 months of operation. The patellar apprehension tests were negative. At last follow-up, the FAA, mLDFA, LPD, and TT-TG were (15.6±2.7)°, (83.0±2.1)°, (5.0±2.6) mm, and (20.5±2.5) mm, respectively; the VAS score, Lysholm score, Tegner score, and Kujala score were 2.4±1.4, 93.4±7.8, 6.8±1.5, and 89.0±8.0, respectively. There were significant differences in the above indicators between pre- and post-operation (P<0.05). ConclusionDDFO combined with MPFL reconstruction for the recurrent patellar dislocation with excessive FAA (≥30°) can achieve good short-term effectiveness, significantly reduce knee pain, and improve function.
Objective To establish a three-dimensional finite element analysis model of the knee joint in fresh frozen cadavers, to verify the validity of the model and to simulate the stress distribution characteristics of the patellofemoral joint after combined proximal and distal knee extension rearrangement surgery for recurrent patellar dislocation. Methods One male and one female fresh frozen cadavers (4 knees in total), using voluntary body donations, were used to measure the maximum pressure on the patellofemoral articular surface at each passive flexion angle (0°, 30°, 60°, 90°, 120°) of the normal knee joint and the model after combined proximal and distal knee extension rearrangement surgery for recurrent patellar dislocation with tibial tuberosity-trochlear groove distance (TT-TG) value >2.00 cm using pressure-sensitive paper, respectively. Then, the 2 freshly frozen cadavers were used to construct three-dimensional finite element models of normal knee joints and postoperative knee joints, and the maximum pressure on the patellofemoral articular surface was measured at various passive flexion angles. The maximum pressure was compared with the measurement results of the pressure-sensitive paper to verify the validity of the three-dimensional finite element model. In addition, the maximum pressure on the patellofemoral joint surface measured by three-dimensional finite element was compared between the normal knee joint and the postoperative knee joint at various passive flexion angles, so as to obtain an effective three-dimensional finite element model for the simulation study of the stress distribution characteristics of the patellofemoral joint after combined proximal and distal knee extension rearrangement surgery for recurrent patellar dislocation. ResultsThe maximum pressure on the patellofemoral joint surface measured by pressure-sensitive paper and three-dimensional finite element measurements were similar at all passive flexion angles in the normal knee joint, with a difference of −0.08-0.06 MPa; the maximum pressure on the patellofemoral joint surface measured by pressure-sensitive paper and three-dimensional finite element measurements were also similar at all passive flexion angles in the knee after combined proximal and distal knee extension rearrangement surgery, with a difference of −0.04-0.09 MPa. The maximum pressure on the patellofemoral joint surface measured by three-dimensional finite elements were also similar between the normal knee joint and the knee joint after combined proximal and distal knee extension rearrangement surgery at all passive flexion angles, with a difference of −0.50-−0.03 MPa. ConclusionThe three-dimensional finite element model of the normal knee joint and the knee joint after combined proximal and distal knee extension rearrangement surgery can accurately and effectively quantify the change in the maximum pressure on the patellofemoral joint surface; for recurrent patellar dislocations with TT-TG value>2.00 cm, the combined proximal and distal knee extension rearrangement surgery can achieve a maximum pressure of the patellofemoral joint surface similar to that of the normal knee joint.
ObjectiveTo evaluate the operability and effectiveness of a self-developed patellar bone canal locator (hereinafter referred to as “locator”) in the reconstruction of the medial patellofemoral ligament (MPFL). Methods A total of 38 patients with recurrent patellar dislocation who met the selection criteria admitted between January 2022 and December 2022 were randomly divided into study group (the patellar canal was established with a locator during MPFL reconstruction) and control group (no locator was used in MPFL reconstruction), with 19 cases in each group. There was no significant difference in baseline data between the two groups (P>0.05), such as gender, age, body mass index, disease duration, patella Wiberg classification, constituent ratio of cartilage injury, Caton index, tibia tubercle-trochlear groove, and preoperative Lysholm score, Kujal score, Tegner score, visual analogue scale (VAS) score, and so on. The Lysholm score, Kujal score, Tegner score, and VAS score were used to evaluate knee joint function before operation and at 3 days,1 month, 3 months, and 6 months after operation. The ideal prepatellar cortical thickness and canal length were measured before operation, and the actual prepatellar cortical thickness and canal length after operation were also measured, and D1 (the distance between the ideal entrance and the actual entrance), D2 (the ideal canal length minus the actual canal length), D3 (the ideal prepatellar cortical thickness minus the actual prepatellar cortical thickness) were calculated.ResultsPatients in both groups were followed up 6-8 months (mean, 6.7 months). The incision length and intraoperative blood loss in the study group were smaller than those in the control group, but the operation time was longer than that in the control group, the differences were significant (P<0.05). There was no complication such as incision infection, effusion, and delayed healing in both groups, and no further dislocation occurred during follow-up. One patient in the study group had persistent pain in the anserine area after operation, and the symptoms were relieved after physiotherapy. The VAS score of the two groups increased significantly at 3 days after operation, and gradually decreased with the extension of time; the change trends of Lysholm score, Kujal score, and Tegner score were opposite to VAS score. Except that the Lysholm score and Kujal score of the study group were higher than those of the control group at 3 days after operation, and the VAS score of the study group was lower than that of the control group at 3 days and 1 month after operation, the differences were significant (P<0.05), there was no significant difference in the scores between the two groups at other time points (P>0.05). Patellar bone canal evaluation showed that there was no significant difference in preoperative simulated ideal canal length, prepatellar cortical thickness, and postoperative actual canal length between the two groups (P>0.05). The postoperative actual prepatellar cortical thickness of the study group was significantly smaller than that of the control group (P<0.05). D1 and D3 in the study group were significantly higher than those in control group (P<0.05), but there was no significant difference in D2 between the two groups (P>0.05). ConclusionThe locator can improve the accuracy of MPFL reconstruction surgery, reduce the possibility of intraoperative damage to the articular surface of patella and postoperative patellar fractures.