• Jannik Frings, Peter Balcarek, Philippe Tscholl, Michael Liebensteiner, Florian Dirisamer, and Paola Koenen.
• Department of Trauma and Orthopaedic Surgery, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany; ARCUS Kliniken Pforzheim, Pforzheim, Germany; Department of Orthopedic Surgery and Musculoskeletal Trauma Care Division, HUG-Hôpitaux Universitaires Genève, Geneva, Switzerland; Orthopedic Surgery, Medical University of Innsbruck, Innsbruck, Austria; Orthopedics & Sports Medicine Linz, UMIT - Private University for Health Sciences, Medical Informatics and Technology, Hall, Austria; Department of Orthopedics, Trauma Surgery and Sports Medicine, Cologne Merheim Medical Center, University of Witten/Herdecke, Cologne, Germany.
• Dtsch Arztebl Int. 2020 Apr 17; 117 (16): 279286279-286.

BackgroundPrimary patellar dislocation is often the initial manifestation of patellofemoral instability. Its long-term consequences can include recurrent dislocation and permanent dysfunction of the knee joint. There is no consensus on the optimal treatment of primary patellar dislocation in the relevant literature. The main prerequisite for a good long-term result is a realistic assessment of the risk of recurrent dislocation.MethodsWe carried out a systematic literature search in OvidSP (a search engine for full-text databases) and MEDLINE to identify suitable stratification models with respect to the risk of recurrent dislocation.ResultsIn the ten studies included in the current analysis, eight risk factors for recurrence after primary patellar dislocation were identified. Six studies revealed a higher risk in younger patients, particularly those under 16 years of age. The sex of the patient had no clear influence. In two studies, bilateral instability was identified as a risk factor. Two anatomical risk factors-a high-riding patella (patella alta) and trochlear dysplasia-were found to have the greatest influence in six studies. In a metaanalysis of five studies, patella alta predisposed to recurrent dislocation with an odds ratio (OR) of 4.259 (95% confidence interval [1.9; 9.188]). Moreover, a pathologically increased tibial tuberosity to trochlear groove (TT-TG) distance and rupture of the medial patellofemoral ligament (MPFL) on the femoral side were associated with higher recurrence rates. Patients with multiple risk factors in combination had a very high risk of recurrence.ConclusionThe risk of recurrent dislocation after primary patellar dislocation is increased by a number of risk factors, and even more so when multiple such risk factors are present. Published stratification models enable an assessment of the individual risk profile. Patients at low risk can be managed conservatively; surgery should be considered for patients at high risk.

8 keywords...

hide…