Pseudocyclops lesion treated conservatively: a case report

Abstract

Background

This case report explores the rare complication of a pseudocyclops lesion within an anterior cruciate ligament autograft, identified in a patient with a recent knee injury and an existing anterior cruciate ligament autograft graft. Notably, this case was managed conservatively, diverging from typical surgical interventions, and resulted in a successful outcome.

Case presentation

A 37-year-old Caucasian male with a prior anterior cruciate ligament autograft sustained a new knee injury; 9 days post-injury, he presented with persistent pain and swelling, exacerbated by weight-bearing, and limited knee extension, though no instability was noted. Non-contrast magnetic resonance imaging revealed a partial tear in the distal anterior fibers of the anterior cruciate ligament autograft, with a 2.5 × 1.3 cm extrusion extending toward Hoffa’s fat pad. The patient was prescribed nonsurgical rehabilitation, which proved effective.

Conclusions

This case underscores the potential of conservative management for pseudocyclops lesions. The successful non-surgical treatment of the pseudocyclops lesion expands the therapeutic options available for similar cases and contributes to the broader understanding of postoperative anterior cruciate ligament autograft pathologies.

Introduction

Anterior cruciate ligament (ACL) reconstructions are a standard intervention for patients suffering from significant ACL injuries, which can severely impair knee function. While the procedure is generally successful, complications are not uncommon, with incidence rates ranging from 10% to 25% among patients [1]. It is reported that 20% to 35% of ACL reconstructions demonstrate cyclops lesions during second-look arthroscopy and 80% of them are asymptomatic [2]. Some of these cyclops lesions are likely pseudocyclops lesions that have a similar appearance [3, 4]. This case report presents a detailed examination of a pseudocyclops lesion occurring within a patient with an existing ACL autograft (ACL graft). Although rare, this complication poses a distinct challenge in clinical management [1, 3, 4]. The lesion was identified in a patient who had sustained a recent knee injury. In this case, a conservative management approach was adopted, in contrast to the more commonly used surgical interventions for similar complications. Nonsurgical rehabilitation led to a successful outcome, with the patient reporting minimal symptoms at a 2-year follow-up. This case underscores the potential for conservative management strategies in the treatment of certain ACL reconstruction complications and contributes to the broader understanding of postoperative ACL graft pathologies.

Case report

In this comprehensive case study, we detail the clinical course of a 37-year-old Caucasian male with a prior ACL graft who experienced a new basketball-related knee injury; 9 days after the incident, the patient sought care for persistent pain and swelling in the operated knee. Notably, the pain intensified under weight-bearing conditions, although the knee demonstrated no instability. A notable limitation in knee extension was also observed. Given these symptoms, the patient was advised to undergo a noncontrast 3 Tesla magnetic resonance imaging (MRI). The imaging results revealed a partial tear in the distal anterior fibers of the ACL graft, with the torn fibers being displaced anteriorly. The tear was characterized by a 2.5 × 1.3 cm extrusion extending through the defect toward Hoffa’s fat pad, as illustrated in Fig. 1a, b, c, and d. In lieu of surgical intervention, the patient was prescribed a regimen of nonsurgical rehabilitation. This included passive and active range of motion exercises, quadriceps strengthening, and progressive loading. This conservative treatment approach proved effective, culminating in the patient reporting minimal to no symptoms at a 2-year follow-up.

Fig. 1

a Sagittal proton density fat saturated image demonstrating the partial tearing and anterior flipping (arrow) of the distal fibers of the ACL graft, b sagittal T1 image demonstrating the partial tearing and anterior flipping (arrow) of the distal fibers of the ACL graft, c coronal proton density fat saturated image (arrow) demonstrating well-defined extrusion, d axial proton density fat saturated image (arrow) demonstrating the pseudocyclops lesion

Discussion

Arthroscopic reconstructions of the ACL utilizing autografts are commonplace. Despite the general success of this procedure, a spectrum of complications has been recognized, with MRI serving as the primary diagnostic tool in the context of an ACL graft. Documented complications include graft impingement, rupture, cystic degeneration, postoperative infection, arthrofibrosis (both diffuse and localized, such as the cyclops lesion), and abnormalities at the donor site [1, 5,6,7]. Among these, the pseudocyclops lesion represents a rare traumatic sequela post-arthroscopic ACL reconstruction, characterized by a partial anterior tear of the distal ACL graft [3]. This tear results in the anterior displacement of the torn fibers, mimicking the appearance of a cyclops lesion [3]. However, it is distinct from the true cyclops lesion, which is composed of fibrotic tissue, as the pseudocyclops lesion originates from torn ACL fibers.

Resection of the angiofibroma in a cyclops lesion constitutes the standard intervention for symptomatic patients, with nonsurgical approaches typically yielding unsatisfactory outcomes [8]. However, the MRI of the patient under discussion revealed a pseudocyclops lesion, a variant with no nonsurgical management in the literature. The patient presented underwent a successful conservative therapy prior to considering surgical options, indicating potential benefits of such treatment in similar cases.

Conclusions

This report presents an instance of conservative rehabilitative management for a pseudocyclops lesion in an ACL graft, thereby expanding the spectrum of therapeutic strategies.