Question:
In patients with primary acute traumatic patellar dislocation, how does autograft medial-third patellar-tendon reconstruction of the medial patellofemoral ligament (MPFL) compare with nonoperative treatment?
Design:
Randomized (unclear allocation concealment), unblinded, controlled trial with mean follow-up of 38 to 48 months.
Setting:
The Instituto Vita and the University of São Paulo, Brazil.
Patients:
Patients ≥12 years of age with a primary acute traumatic lateral patellar dislocation in the previous 3 weeks were included in the study. Exclusion criteria were previous surgery on the affected knee, preexisting knee disorder on the affected knee, coexistent tibiofemoral ligament lesion requiring repair, large osteochondral fragments requiring fixation, neuromuscular disease or congenital disorders, patellar dislocation or instability before the traumatic dislocation, or history of nontraumatic patellar dislocation. 42 patients (mean age, twenty-four years) were randomized; 39 patients (93%) completed follow-up.
Intervention:
Patients were allocated to reconstruction of the MPFL (n = 21; 21 knees) or nonoperative treatment (n = 18; 20 knees). In the reconstruction group, possible cartilage lesions were treated arthroscopically first, and then incisions were made to reach the patellar tendon. Nonabsorbable sutures were placed between the periosteum and the medial third of the patellar tendon to safely rotate the graft. The femoral insertion of the MPFL covered the posterior area proximal to the medial epicondyle. A tunnel of the same diameter as the graft was made posterior and superior to the medial epicondyle and anterior and inferior to the adductor tubercle, and anchored with an absorbable interference screw. The distal edge of the vastus medialis muscle was then sutured to the graft that reconstructed the MPFL, providing a dynamic component to the reconstruction. No lateral retinacular release was performed. Postoperatively, patients used a knee immobilizer for 3 weeks and a physiotherapist began isometric quadriceps exercises, analgesia, cryotherapy, and electrical stimulation. A physiotherapist also performed passive knee mobilization, and weight-bearing was allowed immediately after surgery. In the third postoperative week, exercises increased (including ergometric bicycling and the progression from closed kinetic to open chain exercises) in intensity to allow a return to previous sports activities at 10 to 12 weeks. Patients allocated to nonoperative treatment wore a brace that held the knee in extension for 3 weeks followed by physical therapy, focusing on range of knee movement and quadriceps strengthening. Patients also received analgesia, cryotherapy, and electrical stimulation and were permitted to bear weight after 3 weeks. Exercises increased in intensity to allow a return to previous sports activities at 16 to 24 weeks.
Main outcome measures:
Pain and quality of life measured by the Kujala score (0 to 100; 100 = no disability) and recurrence (a recurring patellar dislocation requiring a medical visit) or patellar subluxation.
Main results:
Patients who received reconstruction of the MPFL had a higher Kujala score than did patients who received nonoperative treatment (88.9 vs. 70.8, p = 0.001). More patients in the reconstruction group had good or excellent results on the Kujala score than did patients in the nonoperative group (71.4% vs. 25.0%, p = 0.003). In the nonoperative group, 4 patients had a recurrence and 3 patients had a subluxation, whereas no patients in the reconstruction group had recurrences or subluxations.
Conclusion:
In patients with primary acute traumatic patellar dislocation, reconstruction of the MPFL produced better pain relief, higher quality-of-life results, and lower recurrence rates than those produced with nonoperative treatment.
Source of funding: Not stated.
For correspondence: Mr. A.C. Bitar, Instituto Vita, Rua Mato Grosso, 306, 1st Floor, Higienopólis, São Paulo, SP 01239-040, Brasil. E-mail address: isabela@vita.org.br
Disclosure: The author did not receive payments or services, either directly or indirectly (i.e., via his institution), from a third party in support of any aspect of this work. He, or his institution, has had a financial relationship, in the thirty-six months prior to submission of this work, with an entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. The author has not had any other relationships, or engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.
The study by Bitar and colleagues is one of the first clinical trials to support better results with MPFL autograft reconstruction than with rehabilitation for younger patients after primary acute traumatic patellar dislocation. Previous systematic reviews comparing variable surgical procedures with nonoperative treatment have not shown benefit. This study showed a beneficial effect of autograft of the medial one-third of patellar tendon for acute MPFL reconstruction at two years with a validated patient-reported outcome measure (Kujala) as well as prevention of future episodes of instability (dislocations and subluxations).
The major clinical question is with regard to the context in which these results should be applied. This study was performed in a single region with a relatively small number of patients. Before widespread adoption of this procedure for acute primary traumatic patellar dislocation, these results should be replicated in a multicenter randomized controlled trial involving several surgeons to confirm the generalizability of these encouraging findings.
Because this technique is relatively new, especially in the United States where reconstruction MPFL is performed by autograft or allograft hamstrings, surgeons would have to learn this technique and consider it for patients indicated for MPFL reconstruction. In future multicenter, multiple-surgeon studies, the rehabilitation should be identical, time of return to sport or activity quantified, and economic and quality-of-life outcomes assessed to appropriately evaluate this technique as a potentially promising improvement for patients. In conclusion, this technique is not yet ready for widespread adoption.