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Surgical treatment of medial patellofemoral ligament avulsion has benefits, study says
Some cases of acute avulsion may require surgery for optimal recovery, one physician has found.
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Patellar medial patellofemoral ligament avulsion with an osteochondral fracture of the medial patellar margin seems to benefit from initial fixation when compared with simple arthroscopic removal, according to the results of a recent study.
The findings were presented by Petri J. Sillanpää, MD, PhD, at the 2010 Annual Meeting of the American Academy of Orthopaedic Surgeons in New Orleans, U.S.A.
The study suggests the potential necessity of operative intervention in some acute femoral and patellar medial patellofemoral ligament (MPFL) avulsion cases.
Not enough studies
“In primary traumatic patellar dislocation, medial patellofemoral ligament avulsion injury may lead to chronic patellar instability,” Sillanpää said. “However, no clinical follow-up data exist on patellar MPFL avulsions with an osteochondral fragment.”
Sillanpää’s team used magnetic resonance imaging (MRI) to retrospectively assess patellar and femoral MPFL avulsion injuries in patients with primary traumatic patellar dislocation. Twenty-one MPFL injuries were classified as patellar, with 35 being classified as femoral.
The patellar MPFL avulsions included 7 patients who underwent surgical fixation of the avulsed patellar medial margin osteochondral fracture. The remaining patellar MPFL avulsions were treated with arthroscopic removal of the fragment.
Femoral MPFL avulsions underwent nonoperative treatment.
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Patellar insertion medial patellofemoral ligament injury with an osteochondral avulsion fracture (arrows). Plain axial radiograph (left) and axial MRI (right) of the same patient. Images: Sillanpää PJ |
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Surgical intervention may be needed
The median age of patients in the study was 21 years, and 43 patients were available for follow-up at a mean of 7 years. They were examined by an independent observer for patellar instability, subjective symptoms and functional limitations.
Sillanpää reported patellar instability in 53% of patients who underwent nonoperative treatment for MPFL avulsion. Conversely, of the seven patellar avulsions treated operatively, patellar instability was reported in one patient (14%).
Furthermore, of the patellar MPFL avulsions treated with removal of the avulsion fragment, patellar instability was reported in six patients (55%).
Fifty-two percent of femoral MPFL avulsion patients regained their pre-injury activity level, compared with 55% of the patellar MPFL avulsion patients who underwent fragment removal and 71% of those who underwent fragment fixation. Median Kujala scores were reported as 85 for femoral avulsion, 88 for patellar avulsion with fragment removal and 91 for patellar avulsion with fragment fixation.
“[The results point toward] acute medial patellofemoral avulsion injuries maybe requiring some sort of surgical intervention,” Sillanpää said. – by Robert Press
Reference:
- Sillanpää P, Maenpaa HM, Mattila VM, Pihlajamaki H. Acute medial patellofemoral ligament avulsion injuries: MRI evaluation and surgical management. Paper#103. Presented at the 2010 Annual Meeting of the American Academy of Orthopaedic Surgeons. March 9-13. New Orleans.
- Petri J. Sillanpää, MD, PhD, can be reached at Consultant Trauma and Orthopaedic Surgeon Tampere University Hospital, Teiskontie 35, 33521 Tampere, Finland; +358-40-5131-792; e-mail: petri.sillanpaa@uta.fi.
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Post-traumatic patellar dislocations are common injuries seen in the active and young adult populations. They have traditionally been managed with nonoperative treatment. The outcomes are inconsistent and studies have reported recurrent dislocations and patellofemoral pain and arthritis in up to 40%. Given the high percentage of associated pathology, MRI of the knee is recommended in all patients who present with acute patellar dislocation.
In several recent biomechanical studies, the medial patellofemoral ligament (MPFL) has been recognized as the most important ligamentous stabilizer preventing lateral dislocation of the patella. An acute patellar dislocation is associated with MPFL injuries at a high rate, and during the last few years some have shown that anatomical MPFL reconstruction is effective and improves clinical symptoms. It seems to offer good recovery of the pre-morbid patella mechanics. The take-home message from Sillanpää´s study supports the growing opinion that, after an acute medial patellofemoral avulsion injury, some sort of surgical intervention is often indicated.
– Per Renström, MD, PhD
Orthopaedics
Today Europe Editorial Board Member