Bone-patellar tendon-bone autograft and female sex are associated with the presence of cyclops lesions and syndrome after anterior cruciate ligament reconstruction.

PURPOSE: Associated risk factors for the development of cyclops lesions have been little. Investigated, because most previous studies have limited their research to cases with symptomatic cyclops lesions (cyclops syndrome). The purpose of this study was to evaluate the presence of cyclops lesions using magnetic resonance image (MRI) at 6 and 12 months after anterior cruciate ligament reconstruction (ACL-R), and to investigate the associated risk factors of cyclops lesions and syndrome. METHODS: A retrospective analysis of patients who underwent ACL-R using bone-patellar tendon-bone (BTPB) or hamstring tendon autograft from 2008 to 2017 was conducted. Predictor variables (age, sex, body mass index [BMI], time from injury to ACL-R, preinjury Tegner activity score, graft, meniscal and cartilage injury, and notch width index on MRI for the presence of cyclops lesions and syndrome were analyzed with multivariate logistic regression. RESULTS: Four hundred and fifty-five patients (225 males and 230 females) were enrolled. One hundred and four patients (22.9%) had cyclops lesions, and all cyclops lesions were detected on MRI at 6 months post-operatively. In addition, 20 patients (4.4%) had cyclops syndrome which means that these were symptomatic cases. The risk factors for presence of cyclops lesions were BPTB autograft (OR = 2.85; 95% CI 1.75-4.63; P < 0.001) and female sex (OR = 2.03; 95% CI 1.27-3.25; P = 0.003). The presence of cyclops syndrome increased with graft (BPTB) (OR = 18.0; 95% CI 3.67-88.3; Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation P < 0.001), female sex (OR = 3.27; 95% CI 1.07-10.0; P = 0.038), and increased BMI (OR = 1.21; 95% CI 1.05-1.39; P = 0.008). CONCLUSIONS: All cyclops lesions were detected 6 months after ACL-R, and the majority of them were asymptomatic. BPTB autograft and female sex were the significant risk factors for the presence of cyclops lesions and syndrome. In addition, increased BMI was associated with a higher risk of developing cyclops syndrome. When BPTB autograft is used for a female patient, full active knee extension should be encouraged in the early period after ACL-R to prevent cyclops lesion formation. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Thymol turbidity test is associated with the risk of cyclops syndrome following anterior cruciate ligament reconstruction.

BACKGROUND: Cyclops nodule formation is a serious complication after anterior cruciate ligament (ACL) reconstruction. The purpose of our study was to investigate whether an increase in thymol turbidity test (TTT) values is involved in the development of cyclops nodule formation or cyclopoid scar formation following ACL reconstruction. METHODS: Between 2011 and 2014, 120 cases underwent outside-in ACL reconstruction. Forty-seven patients who had high TTT values were individually matched for age, sex, body mass index, and meniscus injury to a low TTT value group of 47 patients. The primary outcome was the occurrence of cyclops nodule formation or cyclopoid scar formation. All 94 patients were divided into 3 groups using surgical records and intra-operative video to enable a sub-analysis. The groups were a no-cyclops group, a cyclopoid group, and a cyclops group. Blood examinations, including TTT, and knee range of motion evaluations were performed before surgery, 3 months after surgery, and 1 year after surgery. RESULTS: There were no differences in preoperative demographic data between the two groups. TTT values did not significantly influence cyclopoid scar formation (OR, 1.67; 95% CI, 0.62 to 4.66; p = 0.362). However, patients with cyclops nodule formation showed significantly higher TTT values than the control patients. (OR, 9.34; 95% CI, 1.94 to 90.3; p = 0.002). Knee extension loss was observed in the cyclopoid and cyclops groups 3 months after reconstruction. In the cyclops group, arthroscopic resection of the cyclops nodule was performed 3 months after reconstruction. Eventually, almost full range of motion was restored in all patients. CONCLUSIONS: High TTT values before ACL reconstruction were an indicator of cyclops nodule formation. Furthermore, cyclopoid scar formations may not be the result of an individual's immune reaction but that of extension loss in the early post-reconstruction phase.

Management of Cyclops Syndrome: A case report.

Anterior Cruciate ligament (ACL) is a typical athletic injury. One of the most frequent complication after ACL reconstruction is reduced range of motion (ROM) due to the impingement on the inter-condylar notch of a fibrous tissue mass, defined as Cyclops Syndrome. We report the case of a 25 years old male, who underwent reconstruction of ACL with Gracilis-semitendinosus (GR-ST) tendons with delayed onset of loss of knee extension seven years after ACL reconstruction. Clinical and magnetic resonance image (MRI) findings were consistent with Cyclops syndrome. The patient underwent arthroscopy in May 2015, which revealed a fixed fibrous nodule impinging on the inter-condylar notch in extension that was treated by mechanical shaving, radiofrequency ablation remodeling inter-condylar notch and releasing of the ACL transplant. After surgery our patient returned to his routine activities after 5 days and started running about 10 days later, without anterior knee pain and without deficit of hyperextension.

A tight anterosuperior intercondylar notch may increase the risk of cyclops syndrome after anterior cruciate ligament reconstruction using a quadruple semi-tendinosus short autograft.

BACKGROUND: Cyclops syndrome is loss of terminal knee extension caused by a fibrous nodule developed in the anterior intercondylar notch. The many known risk factors include preoperative motion-range limitation, tibial tunnel malposition, and tight hamstrings. The primary objective of this study was to assess whether intercondylar notch size was associated with the risk of cyclops syndrome or graft tear after anterior cruciate ligament (ACL) reconstruction using a quadruple semi-tendinosis autograft. The secondary objective was to determine whether intercondylar notch size was associated with functional outcomes. HYPOTHESIS: A narrow intercondylar notch is associated with higher risks of cyclops syndrome and poor functional outcomes. METHODS: Consecutive patients who underwent ACL reconstruction by quadruple semi-tendinosus autograft were included retrospectively. Preoperative magnetic resonance imaging scans were assessed by a single senior surgeon, who determined the conventional notch width index (NWI) and the anterior NWI (aNWI) for each patient. RESULTS: The 120 included patients had a mean follow-up of 2.4±0.8 years. Among them, 20 (16.7%) experienced cyclops syndrome and 7 (5.8%) graft rupture. At last follow-up, 26 (21.7%) had not returned to sports and only 47 (39.2%) had returned to sports at the pre-injury level. The mean Lysholm score was 87.9±13.5 and the main subjective IKDC score was 84±13. A narrow notch was significantly associated with lower likelihoods of returning to sports (p=0.001), returning to the same sport (p<0.0001), and returning to the pre-injury sport level (p=0.004). By multivariate analysis, only the aNWI index was significantly associated with the risk of cyclops syndrome (p<0.0001). An aNWI index lower than 0.18 had 85% sensitivity and 78% specificity for predicting cyclops syndrome. CONCLUSION: A narrow anterosuperior intercondylar notch may increase the risk of cyclops syndrome after ACL reconstruction using a quadruple semi-tendinosus graft but is not associated with the risk of graft rupture. LEVEL OF EVIDENCE: IV, retrospective observational cohort study.

Cyclops syndrome following anterior cruciate ligament reconstruction: Can relapse occur after surgery?

Symptomatic cyclops lesions are complications that can be seen at rates of up to approximately 10% after anterior cruciate ligament reconstruction. However, recurrent cyclops lesions have rarely been documented. There are case rare series in the literature regarding the treatment of recurrent cyclops lesion. Future large studies are needed to investigate factors contributing to the development of cyclops lesions and syndrome and treatment options.

Recurrent cyclops lesion after primary resection of fibroreactive nodule following anterior cruciate ligament reconstruction.

In this case report featured in World Journal of Orthopedics, Kelmer et al describe a rare finding of a 28-year-old female patient who presented with a recurrent fibroreactive nodule 7 months following the resection of a primary cyclops lesion, suggesting recurrent cyclops syndrome. The patient had undergone an initial anterior cruciate ligament reconstruction for a non-contact right knee injury and reported successful recovery. Two years later, the patient sustained a repeat right knee injury followed by a positive McMurray test and acute pain with terminal extension. Arthroscopic synovectomy confirmed magnetic resonance imaging (MRI) finding of a cyclops lesion, which was surgically removed. Seven months postoperatively, the patient reported stiffness and difficulty with terminal extension. Repeat MRI indicated a recurrent cyclops lesion, which was surgically resected. Following resection of the second lesion, the patient underwent physical therapy and achieved full range of motion, maintaining complete recovery 19 months postoperatively. Recurrent cyclops lesions have rarely been reported in the literature, and this article is novel in its report of recurrent cyclops syndrome following a bone-patellar tendon-bone allograft. The presentation of this unusual finding exposes a need for further investigation of cyclops lesion pathology, which will aid its prevention and treatment.

Association of COVID-19 Lockdown With Increased Rate of Cyclops Syndrome in Patients With Unexpected Home-Based Self-Guided Rehabilitation After ACL Reconstruction.

Background: The risk of cyclops syndrome increases significantly after anterior cruciate ligament (ACL) reconstruction (ACLR) if complete extension is not recovered before the sixth postoperative week. The lockdown in France due to the COVID-19 pandemic led to an absence of supervised rehabilitation, requiring unexpected self-rehabilitation in patients who underwent ACLR just before lockdown. Purpose: To determine the rate of cyclops syndrome after ACLR in patients who underwent self-rehabilitation during lockdown. Study Design: Cohort study; Level of evidence, 3. Methods: A total of 75 patients receiving a hamstring graft for ACLR during the COVID-19 pandemic between February 10, 2022, and March 16, 2020, carried out self-rehabilitation during part of their first 6 postoperative weeks using exercise videos on a dedicated website. Clinical examination was performed at a minimum 1-year follow-up with International Knee Documentation Committee (IKDC), Lysholm, Tegner, and ACL-Return to Sport after Injury (ACL-RSI) scores. This group was compared with a matched-pair control group of 72 patients who underwent surgery in 2019 and completed postoperative supervised rehabilitation with a physical therapist. Rates and reasons for second surgery (arthrolysis, meniscal procedure) were also recorded. Results: In the COVID group (n = 72; 3 patients were lost to follow-up), the mean follow-up was 14.5 ± 2.1 months (range, 13-21) and rate of reoperation for clinical cyclops syndrome was 11.1% (n = 8). The rate of cyclops syndrome was significantly lower (1.4%) in the control group (P = .01). In the COVID group, 8 patients underwent anterior arthrolysis at a mean of 8.6 months after the primary surgery, and 4 patients underwent another surgical intervention (meniscal procedure [n = 3], device removal [n = 1]). In the COVID group, mean Lysholm was 86.6 ± 14.1 (range, 38-100), Tegner was 5.6 ± 2.3 (range, 1-10), subjective IKDC was 80.3 ± 14.7 (range, 32-100) and ACL-RSI score was 77.3 ± 19.7 (range, 33-100). Conclusion: The rate of cyclops syndrome after ACLR was significantly greater in the COVID group versus the matched controls. The dedicated website was not effective at supporting self-guided rehabilitation and could benefit from interactive improvements so it is at least as effective as supervised rehabilitation.

Postoperative regular use of a self-rehabilitation mobile application for more than two weeks reduces extension deficit and cyclop syndrome after anterior cruciate ligament reconstruction.

PURPOSE: To investigate the minimum use that correlates with the best outcomes in term of complications associated with self-directed rehabilitation mobile application and to explore the user profile and usage habits. METHODS: This was a single-center retrospective study of 356 patients who underwent ACL reconstruction surgery between November 2019 and August 2020. Complications were defined as the presence of an extension deficit ≥ 5° after 6 weeks and/or the presence of cyclops syndrome. The demographics, sports competition level and number of connections were collected by the application. RESULTS: The complication rate was reduced 4.2-fold with at least 2 weeks of use (2.4% (3/123) (with 0.8% (1/123) of cyclops syndrome) versus 10.8% (23/212) (with 3.3% (7/212) cyclops syndrome), p = .04). The mean duration of use was 20 ± 23 days with a frequency of 2.1 ± 2.3 connections per day. The usage rate was 50% in week 1, 35% in week 2, and 24% in week 3. There was one peak in the abandon rate during the first few days of use and a second peak at Day 10 when physiotherapy sessions started. There were two dips in the abandon rate associated with the follow-up visits at Days 21 and 45. Greater use was found in older patients (p = .0001) and female patients (p = .04). CONCLUSIONS: When using the application for a minimum of 2 weeks, the risk of complications was reduced 4.2-fold. The typical users of a self-directed rehabilitation application after ACL surgery in this study were women and patients over 30 years of age. LEVEL OF EVIDENCE: IV, retrospective.

Recurrent cyclops lesion after primary anterior cruciate ligament reconstruction using bone tendon bone allograft: A case report.

BACKGROUND: Cyclops lesions are a known complication of anterior cruciate ligament (ACL) reconstruction, with symptomatic cyclops syndrome occurring in up to 11% of surgeries. Recurrent cyclops lesions have been rarely documented; this case study documents the successful treatment of a recurrent cyclops lesion. CASE SUMMARY: A 28-year-old female presented following a non-contact injury to the right knee. Workup and clinical exam revealed an ACL tear, and arthroscopic reconstruction was performed. Two years later a cyclops lesion was discovered and removed via arthroscopic synovectomy. Seven months postoperatively, the patient presented with pain, stiffness, and difficulty achieving terminal extension. A smaller recurrent cyclops lesion was diagnosed, and a repeat synovectomy was performed. The patient recovered fully. CONCLUSION: To the best of our knowledge, this is the first documented case of recurrent cyclops lesion after bone-patellar tendon-bone allograft ACL reconstruction presenting as cyclops syndrome.

Femoral intercondylar notch: Accuracy of a novel MRI measurement protocol.

OBJECTIVE: The most common mechanical complication following an anterior cruciate ligament (ACL) reconstruction is joint stiffness, due in part to cyclops syndrome. A narrow intercondylar notch is an anatomical risk factor. A reliable preoperative notch measurement would help anticipate proper graft size, or plan a notchplasty during the ligament reconstruction, if necessary. No study has yet assessed the accuracy of the methods used to measure notch size. HYPOTHESIS: The novel measurement protocol proposed in this study would be more reproducible than the reference technique. METHODS: A total of 20 preoperative knee MRIs performed during the assessment of an ACL rupture were randomly selected. The notch size was measured using 2 methods: traditional (ratio of the notch and metaphyseal widths measured on a line drawn through the popliteal groove) and novel. The latter was measured using the same ratio but took into account the notch width in its proximal third, according to a coronal slice that passes through the ACL tibial attachment. Three orthopedic surgeons with different levels of experience (senior surgeon, junior surgeon and surgical resident) performed these measurement protocols twice on anonymized MRI scans, 10days apart. Spearman's rank correlation coefficient was used to assess the intraobserver correlations and a concordance index was used to assess the interobserver correlations. The influence of the second MRI reading was analyzed with a bootstrap test. RESULTS: The mean intraobserver reliability was 0.73 for the reference method and 0.83 for the proposed method. The values of the bootstrap tests were higher for the proposed method (0.45 vs. 0.45 and 0.70; p<05 for interobserver; 0.49 vs. 0.69 and 0.62; p<05 for intraobserver). CONCLUSION: The proposed measurement protocol showed a higher reproducibility in assessing notch size than the traditional method. This technique therefore provides a reliable assessment of the intercondylar notch width. LEVEL OF EVIDENCE: IV; retrospective study.

Knee Extension Deficit in the Early Postoperative Period Predisposes to Cyclops Syndrome After Anterior Cruciate Ligament Reconstruction: A Risk Factor Analysis in 3633 Patients From the SANTI Study Group Database.

BACKGROUND: Cyclops syndrome is characterized by a symptomatic extension deficit attributed to impingement of a cyclops lesion within the intercondylar notch. The syndrome is an important cause of reoperation after anterior cruciate ligament reconstruction (ACLR). It has been suggested that remnant-preserving ACLR techniques may predispose to cyclops syndrome, but there is very limited evidence to support this. In general terms, risk factors for cyclops syndrome are not well-understood. PURPOSE: To determine the frequency of and risk factors for reoperation for cyclops syndrome in a large series of patients after ACLR. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: A retrospective analysis of prospectively collected data was performed, including all patients who underwent primary ACLR between January 2011 to December 2017. Patients undergoing major concomitant procedures were excluded. Demographic data, intraoperative findings (including the size of preserved remnants), and postoperative outcomes were recorded. Those patients who underwent reoperation for cyclops syndrome were identified, and potential risk factors were evaluated in multivariate analysis. RESULTS: A total of 3633 patients were included in the study, among whom 65 (1.8%) underwent reoperation for cyclops syndrome. Multivariate analysis demonstrated that preservation of large remnants did not predispose to cyclops lesions (odds ratio [OR], 1.11; 95% CI, 0.63-1.93). The most important risk factor was extension deficit in the early postoperative period. If present at 3 weeks postoperatively, it was associated with a >2-fold increased risk of cyclops syndrome (OR, 2.302; 95% CI, 1.268-4.239; P < .01), which was increased to 8-fold if present 6 weeks after ACLR (OR, 7.959; 95% CI, 4.442-14.405; P < .0001). None of the other potential risk factors evaluated were found to be significantly associated with an increased frequency of cyclops syndrome. CONCLUSION: Failure to regain full extension in the early postoperative period was the only significant risk factor for cyclops syndrome after ACLR in a large cohort of patients. Other previously hypothesized risk factors, such as preservation of a large anterior cruciate ligament remnant, did not predispose to the development of this debilitating postoperative complication.

Cyclops Lesions of the Knee: A Narrative Review of the Literature.

Cyclops lesion is a known complication of anterior cruciate ligament reconstruction (ACLR). Although the incidence of cyclops lesion appears to be decreasing, it remains an important cause of restriction of extension after ACLR. We reviewed the available literature regarding the cyclops lesion and syndrome and cyclops-like lesions to analyze available evidence on cyclops lesions and variants of cyclops lesions. A keyword search in PubMed, Scopus, Web of Science, and EMBASE, Ovid Medline, and Ovid journals provided 47 relevant articles in the English literature, which were used to create this review. We classified cyclops lesions based on clinical presentation, pathology, and location. Risk factors, management options, tips to reduce the condition, and controversies related to the condition have been discussed. Female sex, greater graft volume, bony avulsion injuries, excessively anterior tibial tunnel, double-bundle ACLR, and bicruciate-retaining arthroplasty appear to predispose patients to cyclops lesions. Cyclops syndrome is a cyclops lesion that causes a loss of terminal extension. Arthroscopic debridement is an effective treatment for cyclops syndrome, whereas cyclops lesions are usually managed conservatively. It is important to distinguish between cyclops lesion and cyclops syndrome, as management differs based on symptoms. Cyclops lesion is diagnosed using magnetic resonance imaging. The management of choice for symptomatic lesions is surgical excision. Outcomes after excision are very good, and recurrence is rare.

Incidence and risk factors for cyclops syndrome after anterior cruciate ligament reconstruction: A systematic literature review.

BACKGROUND: Cyclops syndrome after anterior cruciate ligament (ACL) reconstruction is due to a fibrous nodule that develops in the anterior part of the intercondylar notch and prevents full knee extension. The primary objective of this systematic literature review was to evaluate the incidence of symptomatic cyclops lesion after ACL reconstruction. The secondary objective was to identify risk factors for cyclops syndrome. HYPOTHESIS: Cyclops syndrome is common after ACL reconstruction and has several risk factors reported in the literature. METHODS: A systematic literature review was performed by searching the PubMed, Medline, CINAHL, Cochrane, and Embase databases with the key terms 'cyclops' and 'ACL reconstruction'. The data thus retrieved were evaluated independently by two investigators. All articles in English or French that reported the incidence and risk factors of cyclops syndrome after ACL reconstruction were included. RESULTS: The search retrieved the titles and abstracts of 79 articles, of which 20 were selected to be read in full; among these, 10 were included in the study. The incidence of symptomatic cyclops lesion ranged from 1.9% to 10.9%. Identified risk factors were as follows: pre-operatively, knee inflammation and/or motion restriction at the time of ACL reconstruction; intra-operatively, narrow intercondylar notch and excessively anterior position of the tibial tunnel; and post-operatively, persistent hamstring muscle spasm. DISCUSSION: Development of a cyclops lesion is common after ACL reconstruction, occurs early, and may require further surgery. The knowledge of the risk factors provided by this study may improve the ability to devise effective preventive measures. LEVEL OF EVIDENCE: II, systematic literature review.

Hamstring Contracture After ACL Reconstruction Is Associated With an Increased Risk of Cyclops Syndrome.

BACKGROUND: Cyclops syndrome is characterized by loss of terminal knee extension due to proliferative fibrous nodule formation in the intercondylar notch. This complication occurs in the early postoperative period after anterior cruciate ligament reconstruction (ACLR). The pathogenesis of Cyclops syndrome is not well understood. HYPOTHESIS: Persistent hamstring contracture after ACLR is associated with an increased risk of subsequent Cyclops syndrome. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: The files of 45 patients who underwent arthroscopic debridement of a Cyclops lesion after ACLR were analyzed. Recorded data included demographic information and technical details of surgery. Preoperative magnetic resonance images were also analyzed, and patients with femoral bone bruising were identified. Passive and active range of motion were recorded in all patients preoperatively and at 3 and 6 weeks after surgery to address the Cyclops lesion. Passive extension deficit was evaluated in comparison with the contralateral limb and classified as secondary to hamstring contracture when contracture was observed and palpated in the prone position and when the extension deficit was reversed after exercises performed to fatigue the hamstrings. A control group was selected using a random numbers table among our entire ACLR cohort. Statistical analysis was performed to analyze differences between the 2 groups. RESULTS: There was no significant difference between the groups with regard to age at ACLR, sex distribution, time from injury to surgery (P > .05), proportion of professional athletes, presence of femoral bone bruise, or technical aspects of surgery. The overall extension deficit incidence was significantly higher in the Cyclops group at 3 weeks (Cyclops, 71%; control, 22%) (P < .001) and at 6 weeks (Cyclops, 60%; control, 7%) (P < .001). The extension deficit related to hamstring contracture was significantly higher in the Cyclops group at 3 weeks (Cyclops, 58%; control, 22%) (P < .001) and at 6 weeks (Cyclops, 29%; control, 2%) (P < .001). CONCLUSION: The Cyclops lesion is associated with a persistent hamstring contracture at 3 and 6 weeks after ACLR.