Type A or B and 12 had Type C trochlear dysplasia. 1 had excess femoral ante version of 35 degrees. Arthroscopy was performed to assess associated injuries and presence of loose bodies. 8 knees required loose body removal. 6 knees underwent lateral retinacular release. 5 knees had associ- ated tibial tuberosity medialization. 1 knee had an associ- ated anterior cruciate ligament reconstruction. 1 knee with abnormal increased femoral ante version underwent an associated distal femoral derotation osteotomy. An anatomical MPFL reconstruction with MQTFL recon- struction was performed using hamstring autograft. A “Y” graft construct was created with differential tensioning. The proximal limb fixed in 30  knee flexion and the distal limb in 90  . Intraoperative fluoroscopy was not required. Only soft tissue fixation was performed on the femoral and patellar side with this newly devised reconstruction tech- nique and a novel “Pretzel stitch” suturing technique using absorbable sutures. A rapid postoperative rehabilitation protocol was implemented with monthly follow-ups until normalcy and 6 monthly thereafter. Results: All knees achieved full range of motion with normal medio-lateral patello-femoral stability. There was no recurrence of dislocation or subjective instability. No intraoperative complications or major surgery related postoperative complications. 1 patella fracture at 8 months postoperative, was due to a fall from stairs and developed terminal restriction of flexion following fracture fixation. Those in sports could return to their preoperative level of sporting activities (Tegner 1e9). Cases with osteochondral fractures had occasional pain immediate postoperatively which subsided in 1 year. Mean Kujala score improved from 65.4 to 99.6 with KOOS score near normal in all. Conclusion: This novel method of MPFL reconstruction gives excellent results. It avoids bone tunnelling, implants and related complications. It is a safe, effective, reliable and reproducible technique of MPFL reconstruction. Category: Knee - Patellofemoral instability Paper #67: Clinical And Radiological Predic- tors Of Medial Patellofemoral Ligament Reconstruction THOMAS NERI, MD, FRANCE BERTRAND BOYER, MD, PHD, FRANCE FREDERIC FARIZON, FRANCE REMI PHILIPPOT, MD, PHD, FRANCE Laboratoire Interuniversitaire Biologie Motricité, University hospital of Saint etienne, Saint etienne, FRANCE SUMMARY The objective was to isolate, through a clinical series of 107 patients, the clinical and radiological predictors that can significantly influence the clinical results of the MPFL ligament. ABSTRACT DATA Introduction: Among the numerous techniques avail- able, medial patellofemoral ligament (MPFL) reconstruc- tion is increasingly used for the surgical treatment of objective patellar instability. Although the value of this technique has been demonstrated, few studies have assessed predictors of good clinical results. The main objective of this study was to isolate, through a clinical series of 107 patients, the clinical and radiological predic- tors that can significantly influence the clinical results of the MPFL ligament. Methods: One hundred and seven patients (110 liga- ment reconstructions) presenting an objective patellar instability, were evaluated with a mean follow-up of 55 months (24 to 91). The standardized procedure comprised MPFL reconstruction using the gracilis tendon. Comple- mentary distal bone graft was associated if a preoperative tibial tubercle-trochlear groove (TT-TG) distance exceeded 20 mm or a patella alta. Functional IKDC and Kujala scores were preoperatively assessed and at end of follow-up. Plain X-ray with radiological assessment of patellar height and tilt (Laurin angle, Merchant angle, Maldague classifi- cation) and a CT scan measurement of the patellar tilt (quadriceps contracted and relaxed) and TT-GT distance were performed preoperatively and at 6 months. Femoral tunnel position was assessed following the criteria formulated by Schöttle. The amount of femoral tunnel widening was measured by means of the 3D CT scan image at 6 months. Predictors were determined from univariate and multivariate analyzes integrating clinical and radio- logical criteria pre and postoperative. The variables of interest were defined as the difference in functional scores between pre and postoperative. Results: Clinical factors, such as age, Body Mass Index, number of dislocation, time between the first dislocation and surgery, did not influence functional scores (all p> 0.05). For technical factors: association with a bone graft or incorrect positioning of the femoral tunnel, also had no effect on clinical outcome (p> 0.05). It was the same for preoperative radiological factors: radiological and CT scan tilt, TT-TG distance, patellar height (all p> 0.05). For postoperative radiological factors, patellar height and tilt were not predictors. However, the correction of patellar tilt with quadriceps contracted (p ¼ 0.013) and relaxed (p ¼ 0.003) and the TT-GT distance correction (p ¼ 0.023) were predictors of good clinical results. Discussion and conclusion: For the MPFL ligament reconstruction, predictors of clinical improvement of the patient were patellar tilt and TT-GT distance correction at CT scan. Category: Knee - Patellofemoral instability Paper #68: High Failure Rate After Medial Patellofemoral Ligament Reconstructions. A Nationwide Epidemiological Study Investi- gating 2.572 Medial Patellofemoral Ligament Reconstructions And 24.154 Primary Dislo- cations KASPER SKRIVER GRAVESEN, MD, DENMARK THOMAS KALLEMOSE, MSC, DENMARK LARS BLØND, MD, DENMARK ANDERS TROELSEN, MD, PHD, DMSC,PROF., DENMARK e70 2017 ISAKOS ABSTRACTS