Abstract
Background:
Patellar dislocations are a common adolescent injury with high incidence of osteochondral injury involving the patellofemoral joint with severity ranging from minor chondral injury to large osteochondral fracture (OCF). If not appropriately addressed, patellofemoral OCF can lead to early arthritic sequelae and/or recurrent instability (1-2). Studies comparing OCF excision (LBR) to internal fixation (ORIF) have demonstrated inconsistent outcomes and have often included varied methods of fixation. We aim to compare post-surgical outcomes for patients who undergo ORIF with titanium headless screws versus loose body removal (LBR) for OCF after an acute patellar dislocation (APD).
Objectives:
Patients who undergo ORIF using titanium headless screws with subsequent planned hardware removal will have superior patient reported outcomes compared to patients treated with LBR.
Methods:
This is a retrospective cohort study of patients under 21 years of age treated by single surgeon with either ORIF with titanium headless screw(s) or LBR for an OCF of at least 10mm diameter secondary to traumatic APD between 2018-2024. The primary outcome measures included Knee injury and Osteoarthritis Outcome Score-Patellofemoral subscale (KOOS-PF) and pain rating (0-10 scale). Secondary outcome measures included postoperative complications including infection, stiffness, persistent pain, unexpected return to the OR, and recurrent instability.
Results:
Twenty-four patients were included with 13 undergoing ORIF and 11 undergoing LBR with mean follow up of 3.4 years. Preoperative characteristics did not significantly differ, except the estimated OCF size was larger in the ORIF group compared to the LBR group (3.3cm2 vs 1.5cm2, p = 0.013). Mean postoperative KOOS-PF scores and pain ratings did not differ between groups. Although not statistically significant, the patients undergoing LBR did have higher rates of recurrent instability (5/11) than patients undergoing ORIF (1/13)(p=0.061). Of the 6 patients reporting recurrent instability, 5 experienced subluxations and 1 sustained repeat dislocation requiring surgical intervention. All patients undergoing ORIF had complete healing on intraoperative evaluation at the time of hardware removal.
Conclusion:
This study found no significant difference in patient reported outcomes between patients treated with ORIF using titanium headless screws compared to those treated with LBR despite a significantly larger size of OCF in the ORIF group. Although not statistically significant, this study observed clinically significant differences in recurrent instability rates between patients treated with LBR (45%) versus ORIF (8%). This may suggest ORIF better addresses patellar maltracking, though further research with larger group sizes is needed to draw such conclusions.
