title: Medial patellofemoral ligament reconstruction using a bone groove and a suture anchor at patellar: a safe and firm fixation technique and 3-year follow-up study.
abstract: BACKGROUND
  Graft fixation is critical to the restoration of the medial patella of femoral ligament function and long-term success. Numerous fixations at the patella have been described, while the complications including patellar fractures, violation of the posterior patella and delay of tendon-to-bone healing remain significant challenges. Here, we describe a safe and firm fixation at the patellar for medial patellofemoral ligament (MPFL) reconstruction and explore the safety angle of drilling the suture anchor at different morphology of the patellar. Moreover, we evaluate the results at a 3-year follow-up.
  
  
  METHODS
  Combined bone groove and suture anchor fixation at the patella was performed on 26 patients (16 females, 10 males; mean age 26.3 ± 4.7 years) diagnosed with recurrent patellar dislocation. The drilling direction of the suture anchor referred to the safety angle according to the Wiberg type classification. The safety angle was defined as the angle between the drill tunnel and a line that connected the medial and lateral margins of the patella and was established following computed tomography assessment of 117 patients who were diagnosed with patellar dislocation in our hospital according to the Wiberg type classification (I:29, II:65, III:23). X-ray, Lysholm, Kujala and Tegner scores were obtained preoperatively and at the time of final follow-up.
  
  
  RESULTS
  There were no patellar complications, including fracture and redislocation. Average congruence, patella tilt angles and lateral patella angle were significantly changed (P < 0.01). The Lysholm, Kujala and Tegner scores were significantly increased (P < 0.01). The safe angles of male and female patients according to the patellar Wiberg type classification were less than 45.32 ± 1.76 and 41.20 ± 1.33, 69.74 ± 1.38 and 63.66 ± 1.45 and 84.11 ± 1.67 and 80.26 ± 1.73, respectively.
  
  
  CONCLUSIONS
  We achieved encouraging results with this fixation at the patellar. When drilling from Wiberg type I to type III patellar, the suture anchor should be more vertical. When fixing the patellar of female patients, the drilling suture anchor should be more sloping.
authors.affiliation: Department of Orthopedics, Third Hospital of Hebei Medical University, 139 Ziqiang Road, Shijiazhuang, 050051, Hebei, People's Republic of China.
authors.forename: Hong-De
authors.initials: HD
authors.lastname: Wang
authors.affiliation: Department of Orthopedics, Third Hospital of Hebei Medical University, 139 Ziqiang Road, Shijiazhuang, 050051, Hebei, People's Republic of China.
authors.forename: Jiang-Tao
authors.initials: JT
authors.lastname: Dong
authors.affiliation: Department of Orthopedics, Third Hospital of Hebei Medical University, 139 Ziqiang Road, Shijiazhuang, 050051, Hebei, People's Republic of China. shijungao2015@yahoo.com.
authors.forename: Shi-Jun
authors.initials: SJ
authors.lastname: Gao
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016268:Internal Fixators; D007593:Joint Instability / Q000175:diagnosis / Q000601:surgery; D008023:Ligaments, Articular / Q000293:injuries / Q000601:surgery*; D008297:Male; D031222:Patellar Dislocation / Q000175:diagnosis / Q000601:surgery*; D057071:Patellofemoral Joint / Q000293:injuries / Q000601:surgery*; D019651:Plastic Surgery Procedures / Q000295:instrumentation / Q000379:methods*; D053441:Suture Anchors; D055815:Young Adult
keywords: Combined bone groove and suture anchor fixation; Medial patellofemoral ligament reconstruction; Safety angle