Non‐anatomical MPFL reconstruction and failure to address relevant pathologies are common reasons for treatment injuries following treatment for patellofemoral instability

PURPOSE: Management of patellofemoral instability (PFI) tailored to the individual patoanatomy can be complex with potential pitfalls. However, reports on complications and suboptimal outcomes remain limited. The aim of this study was to analyse problems related to PFI treatment in Denmark. This knowledge can be used to optimize future treatment of PFI. METHODS: Compensation claims from 2004 to 2025 related to PFI were identified in the Danish Patient Compensation Association. Medical records and imaging were independently reviewed by two observers. Radiographs and magnetic resonance imaging were analysed for anatomical risk factors (trochlear dysplasia, patella alta, lateralized tibial tubercle) and to evaluate postoperative surgery. For each patient, the appropriate surgical management was defined according to an á-la-carte principle, and for each patient it was assessed whether treatment had been appropriate. Information about accepted complications and compensation was registered for each case. RESULTS: There were 405 eligible claims. The most frequent cause of treatment injury was surgical malpractice (38%), particularly incorrect femoral graft placement in medial patellar-femoral ligament reconstruction, which accounted for nearly half of these cases. Failure to adequately evaluate or treat anatomical risk factors (20%) often resulted in additional surgery. Nerve injuries (13%) and delayed treatment (8%) were also significant, while deep vein thrombosis (3%) and deep infection (1%) were rare. The 210 claims (54%) being approved received a total compensation of 34 million DKK. CONCLUSION: Many treatment injuries following PFI surgery were in principle preventable. Standardized imaging protocols and treatment algorithms are suggested as means to reduce complications. LEVEL OF EVIDENCE: Level II.