Small, Short, Oblique Patellar Tunnels for Patellar Fixation Do Not Increase Fracture Risk or Complications in MPFL Reconstruction: A Retrospective Cohort Study

Abstract

Background: Large (4.5 mm) and/or transpatellar bone tunnels have been associated with patellar fracture after medial patellofemoral ligament (MPFL) reconstruction. To avoid this outcome, many surgeons now employ suture anchors to affix the MPFL graft to the patella. Purpose: To evaluate the risk of patellar fracture and other outcomes associated with smaller (3.2-mm), short, oblique patellar tunnels as compared with suture anchor fixation in MPFL reconstruction. Study Design: Cohort study; Level of evidence, 3. Methods: A single institution’s electronic medical record was queried for all patients undergoing MPFL reconstruction between March 2010 and December 2018. A chart review of operative reports was utilized to identify those who had undergone MPFL reconstruction. Patients undergoing revision MPFL reconstruction or reconstruction with fully transpatellar bone tunnels were excluded. The incidence of patellar fracture and outcomes were evaluated from chart review. The mean duration of follow-up was >2 years. Results: A total of 384 knees in 352 patients undergoing primary MPFL reconstruction were identified. Small (3.2-mm), short, oblique tunnels were used for patellar fixation in 215 cases, and suture anchors were utilized in 169 cases. The small, oblique tunnels and suture anchor techniques both resulted in a low incidence of patellar fracture, with rates of 0.47% and 0%, respectively. The use of suture anchors was associated with an increased risk of subluxation or dislocation compared with small, oblique tunnels (odds ratio, 3.98; P = .028). No significant difference was found in the need for revision MPFL reconstruction surgery with suture anchors (odds ratio, 1.925; P = .66). Conclusion: The use of small, oblique tunnels with hamstring autograft is a safe means of patellar fixation in MPFL reconstruction. The use of small, oblique tunnels for patellar fixation versus 2 suture anchors can result in material cost savings with no significantly increased risk for fracture as well as an overall reduction in complication rates.

Small (3.2-mm), Short, Oblique Patellar Tunnels for Patellar Fixation in MPFL Reconstruction

“…Other advantages of small, oblique patellar tunnels with looped graft possibly include enhanced graft-to-bone healing by providing a larger area of graft to bone contact and increased cost effectiveness relative to the suture anchor fixation technique. 8 In conclusion, the use of small (3.2-mm), short, oblique patellar tunnels with looped graft is safe, efficacious, and cost-conscious and should be considered a viable option for patellar fixation during MPFL reconstruction.…”

“…7 A recent retrospective cohort study by Deasey et al including 384 knees in 354 patients undergoing MPFL reconstruction presented outcomes with the use of smaller (3.2-mm), short, oblique patellar tunnels for graft fixation. 8 Importantly, they found that the use of smaller tunnels was not associated with an increased incidence of patellar fracture compared with the use of suture anchors. Additionally, they reported only one instance of patellar fracture out of a cohort of 215 knees (incidence 0.46%), which is lower than the historical rates presented in similarly sized studies by Schipouwer et al 5 and Parikh et al 6,8 Deasey et al 8 also showed that the use of these small (3.2-mm), short, oblique tunnels led to a statistically significant decrease in the risk of recurrent patellar instability events compared with suture anchors.…”

“…8 Importantly, they found that the use of smaller tunnels was not associated with an increased incidence of patellar fracture compared with the use of suture anchors. Additionally, they reported only one instance of patellar fracture out of a cohort of 215 knees (incidence 0.46%), which is lower than the historical rates presented in similarly sized studies by Schipouwer et al 5 and Parikh et al 6,8 Deasey et al 8 also showed that the use of these small (3.2-mm), short, oblique tunnels led to a statistically significant decrease in the risk of recurrent patellar instability events compared with suture anchors. The authors hypothesized that the increased risk of recurrent instability may be due to anchor pull-out, which is a risk not found with the use of osseous tunnels and a looped graft.…”

“…7 A recent retrospective study comparing the use of small (3.2-mm), short, oblique patellar tunnels and suture anchors for patellar fixation found that using the smaller tunnels is not associated with an increased risk for patellar fracture, and actually led to a decreased rate of recurrent patellar instability events. 8 In this Technical Note, we describe the senior author's method of using small (3.2-mm), short, oblique patellar tunnels for patellar fixation in MPFL reconstruction (Video 1).…”

Patellofemoral Instability

“…This study highlights the associated, increased risk seen with the use of transverse patellar bone tunnel while performing MPFL reconstruction. Recently, Deasey et al [161] have shown that the use of small-diameter (3.2-mm), oblique patellar bone tunnels was not associated with an increased risk of patellar fracture in comparison with the use of suture anchors for patellar fixation. Deasey et al [161] concluded that the use of small (3.2-mm), short, oblique patellar tunnels can be a safe and reliable method of patellar graft fixation in MPFL reconstruction.…”