Medial patellofemoral ligament reconstruction is superior to active rehabilitation in protecting against further patella dislocations
Straume-Næsheim TM, Randsborg PH, Mikaelsen JR, Årøen A. Knee Surg Sports Traumatol Arthrosc. 2022 Mar 28. doi: 10.1007/s00167-022-06934-3. Epub ahead of print. PMID: 35347375.
Participants with recurrent patellar dislocations that received an isolated reconstruction of the medial patellofemoral ligament and rehabilitation were less likely to report persistent patellar instability than those receiving conservative care. However, both groups had similar improvements in all other outcomes.
The decision to move forward with surgery or conservative care following an injury can be difficult. Someone with a lateral patellar dislocation and no anatomical risk factors for redislocation (e.g., patella alta, trochlear dysplasia) may be an ideal candidate for an isolated medial patellofemoral ligament reconstruction (MPFLR) or conservative treatment. However, we lack information on how to advise a patient who experienced multiple patellar dislocations.
Straume-Næsheim and colleagues performed a randomized clinical trial among people with recurrent lateral patellar dislocations and no anatomical risk factors for another dislocation. They compared the persistence of patellar instability at 12 months between those receiving isolated MPFLR with rehabilitation or diagnostic arthroscopy and rehabilitation.
The authors recruited 61 patients between 2010 and 2019 that had 2 or more patella dislocations, tibial tuberosity trochlear groove distance <20mm, and had a positive apprehension test upon clinical examination. They then randomized 30 participants to receive an isolated MPFLR with rehabilitation (73% female; 18 years old; ~32 months with symptoms). Another 31 patients randomly received rehabilitation after a diagnostic arthroscopy (conservative care; 71% female; 20 years old; ~29 months with symptoms). Rehabilitation focused on strengthening the vastus medialis oblique, stretching the hamstrings, and neuromuscular control of the knee. The study staff assessed participants at 3, 6, and 12 months. Participants completed the following assessments: Knee injury Osteoarthritis Outcome Score (KOOS) to measure knee-related sports function and quality of life, Kujala Score to report pain and instability on patellofemoral joint, Lysholm score to assess knee function, Noyes sport activity rating to determine level of activity, modified Cincinnati knee rating system for knee symptoms and function, and a pain scale.
Overall, people who received conservative care (13 cases, 42%) were 6 times more likely to report persistent patellar instability at 12 months than those receiving an isolated MPFLR (2 cases, ~7%). Both groups experienced improvements in all patient-reported outcomes and range of motion with no differences between groups. Some surgical complications were reported: 6 cases of anterior knee pain and 1 case of complex regional pain syndrome in the thigh. Ultimately, an oversight committee stopped the study early (recruited 61 out of target 100) because of the large difference in persistent patellar instability between groups.
At 12-months, over 40% of the participants receiving conservative care reported persistent patellar instability. It would be helpful to know how the authors defined persistent patellar instability, but it was concerning since the oversight committee stopped the trial. Despite the significant disparity in instability concerns, both groups had comparable improvements in other outcomes. Hence, if a patient primarily focuses on improving pain without concerns for recurrent instability, then conservative care may be appropriate and avoids the risk of surgical complications. However, if a patient plans to return to sport and has concerns about recurrent instability, an isolated MPFLR may be ideal.
Medical professionals and patients need to discuss the primary goal after a patient experiences multiple patellar dislocations. Based on that discussion, they should consider the advantages and disadvantages of each treatment approach.
Questions for Discussion
Which route did your patients with lateral patella dislocations take, conservative or surgical? What were their outcomes? Did they have another dislocation or complain of instability?
- Patellofemoral Instability: Consensus Statement From the AOSSM/PFF Patellofemoral Instability Workshop
- Risk of Redislocation After Primary Patellar Dislocation
- Novel Clinical Prediction Rule for Patellofemoral Rehabilitation
Written by: Jane McDevitt
Reviewed by: Jeffrey Driban