Recent research progress from biological perspective on the mechanism of formation of osteoarthritis after anterior cruciate ligament injury

The anterior cruciate ligament(ACL)mainly plays a role in stabilizing the knee joint by limiting the forward translation of tibial force and rotational force at the tibial joint,and if this ligament is damaged,it will cause joint pain,limited mobility,knee instability,etc.According to related studies,the incidence of traumatic osteoarthritis(PTOA)after ACL injury is as high as 87%,although many studies have shown that patients with ACL injury are susceptible to PTOA,but the exact mechanism is currently unknown.This may be related to biological,structural,and mechanical factors caused by the ligament injury.Previous studies have shown that elevated inflammatory mediators in the joint cavity following ACL injury can lead to chondrocytes necrosis and degradation of the cartilage matrix.These potential biochemical mediators contribute to PTOA formation,and early intervention can reduce future episodes of PTOA.In recent years,many scholars have devoted themselves to studying the potential important factors and signaling pathways involved in the formation of osteoarthritis after ACL injury,and exploring its molecular mechanism,which has led to great progress in this field.This paper mainly studies and discusses the mechanism of osteoarthritis formation after ACL injury from the biological perspective.

The Prevalence Type of the Meniscus Tear in Patients with Anterior Cruciate Ligament (ACL) Injury, in Abu Arish General Hospital, Jazan, KSA

Background: The anterior cruciate ligament (ACL) is the main structure that prevents the forward movement of the tibia about the femur Meniscus tear which is a common finding in patients with anterior cruciate ligament (ACL) injury. Aim: To investigate the prevalence of types of meniscus tears in patients with Anterior Cruciate Ligament (ACL) Injury. Methods: A retrospective study was conducted among inpatients. Clinical evaluation included side-to-side difference in anterior tibial translation (ATT) as measured by a KT-1000 arthrometer (MEDmetric Corp) and a grade of pivot-shift test at final follow-up in all patients. Subsequent meniscal tear was defined by symptoms of joint line pain and/or locking or joint effusion requiring surgical treatment. Results: Most of patients were males (92.6%). The patients were categorized into 5 groups according to age with a mean of age 32.8 ± 10.6. The most common causes of ACL injury were falling down (43.2%), trauma (38.1%) or knee torsion (18.8%). Medial meniscal tear was found in 92 knees (55.7%), while lateral meniscal tear was found in 19 knees (10.8%) and the most common type was the longitudinal tear that was found in 31 knees (17.6%). Similarly, 66.7% of the meniscal flap tears and half of the meniscal bucket-handle tears were significantly associated with loose body (P Conclusion: The present study demonstrated that meniscus tears are more common in individuals with chronic ACL rupture. The main factors contributing to ACL injury were classified as falls, trauma, and knee torsion. Gender was identified as a critical determinant in the etiology of ACL injury. The occurrence of a ramp lesion was associated longitudinal meniscal tears, whereas chodoral injury was associated with the majority of meniscal flap tears and meniscal bucket-handle tears.

Osteotomy combined with anterior cruciate ligament reconstruction for anterior cruciate ligament injury and biplanar deformity

BACKGROUND It has been confirmed that the increased posterior tibial slope over 12 degrees is a risk factor for anterior cruciate ligament injury,and varus deformity can aggravate the progression of medial osteoarthritis.AIM To evaluate the efficacy of modified high tibial osteotomy(HTO)and anterior cruciate ligament reconstruction(ACLR)in the treatment of anterior cruciate ligament(ACL)injuries with varus deformities and increased posterior tibial slope(PTS)based on clinical and imaging data.METHODS The patient data in this retrospective study were collected from 2019 to 2021.A total of 6 patients were diagnosed with ACL injury combined with varus deformities and increased PTS.All patients underwent modified open wedge HTO and ACLR.The degree of correction of varus deformity and the PTS was evaluated by radiography and magnetic resonance imaging.RESULTS All 6 patients(6 knee joints)were followed up for an average of 20.8±3.7 months.The average age at surgery was 29.5±3.8 years.At the last follow-up,all patients resumed competitive sports.The International Knee Documentation Committee score increased from 50.3±3.1 to 87.0±2.8,the Lysholm score increased from 43.8±4.9 to 86±3.1,and the Tegner activity level increased from 2.2±0.7 to 7.0±0.6.The average movement distance of the tibia anterior translation was 4.8±1.1 mm,medial proximal tibial angle(MPTA)was 88.9±1.3°at the last follow-up,and the PTS was 8.4±1.4°,both of which were significantly higher than those before surgery(P<0.05).CONCLUSION Modified open wedge HTO combined with ACLR can effectively treat patients with ACL ruptures with an associated increased PTS and varus deformity.The short-term effect is significant,but the long-term effect requires further follow-up.

Preseason elimination impact on anterior cruciate ligament injury in the national football league

BACKGROUND Anterior cruciate ligament(ACL)injuries represent detrimental injuries in the National Football League(NFL).A significant portion of these injuries often occur in preseason exhibitions.The Coronavirus disease 2019 pandemic presented a unique disruption to preseason NFL football with the cancelation of all preseason games.AIM To compare the incidence of ACL tears through the first eight weeks of the NFL season in 2020 to the mean incidence over the previous 5 seasons(2015-2019)and determine if there was any change in incidence with the elimination of the preseason.METHODS NFL players who suffered ACL tears during the preseason and first eight weeks of the NFL season from 2015-2020 were identified.The number of ACL injuries for the 2015-2019 seasons was compared to the 2020 season for four different timeframes.For each analysis,the cumulative number of ACL injuries to that time point was used to calculate the percent difference for descriptive analysis.Additionally,the number of teams with at least one player suffering an ACL tear were identified and compared using Chi-Squared testing.Finally,a cumulative relative risk was calculated for each week played.RESULTS There were 14 ACL tears through the first four games of the 2020 season,a 118.8%(14 vs 6.4)increase in comparison to the 5-year average over the first 4 regular season weeks of 2015-2019.However,when accounting for injuries occurring during the preseason from 2015-2019,there were 18.6%(14 vs 17.2)fewer total ACL injuries through regular season week 4 with no significant difference in percentage of teams impacted when these preseason injuries were accounted for P=0.394.Results were similar(19 vs 17.2)over 8 total games played(whether regular season or preseason),and over 8 regular season games(P=0.196,P=0.600).CONCLUSION The elimination of the NFL preseason resulted in a higher rate of injuries during the first 4 games of the regular season.However,these increases are offset by the injuries typically sustained during the preseason.This suggests there may be front-loading of injuries over the course of an NFL season,such that players may be more prone to injury when the intensity of play suddenly increases,whether in the preseason or regular season.

Osteoarthritis action alliance consensus opinion-best practice features of anterior cruciate ligament and lower limb injury prevention programs

AIM To identify best practice features of an anterior cruciate ligament(ACL) and lower limb injury prevention programs(IPPs) to reduce osteoarthritis(OA).METHODS This consensus statement started with us performing a systematic literature search for all relevant articles from 1960 through January 2017 in PubM ed, Web of Science and CINAHL. The search strategy combined the Medical Subject Heading(Me SH) and keywords for terms:(1) ACL OR "knee injury" OR "anterior cruciate ligament";(2) "prevention and control" OR "risk reduction" OR "injury prevention" OR "neuromuscular training"; and(3) meta-analysis OR "systematic review" OR "cohort study" OR randomized. We found 166 different titles. The abstracts were reviewed for pertinent papers. The papers were reviewed by at least two authors and consensus of best practice for IPP to prevent OA was obtained by conference calls and e-mail discussions. All authors participated in the discussion.RESULTS The best practice features of an IPP have the following six components:(1) lower extremity and core strengthening;(2) plyometrics;(3) continual feedback to athletes regarding proper technique;(4) sufficient dosage;(5) minimal-to-no additional equipment; and(6) balance training to help prevent injuries. Exercises focused on preventing ankle sprains, hamstring injuries and lateral trunk movements are important. Plyometric exercises should focus on correcting knee valgus movement.Exercises should focus on optimizing the hamstring to quadriceps strength ratio. In order for IPP to be successful, there should be increased education and verbal feedback along with increased athletic compliance. Additional equipment is not necessary. Balance training alone does not significantly reduce injuries, but is beneficial with other exercises. Not enough evidence to recommend stretching and agility exercises, with no ill effects identified. Therefore, we suggest making these optional features.CONCLUSION Best practice features for ACL and lower limb IPPs to help prevent OA contain six key components along with two optional.

Biomechanical Risk Assessment of Non-Contact Anterior Cruciate Ligament Injury in Taekwondo Athletes

Non-contact anterior cruciate ligament(ACL)injury can occur in many sports.It is interrelated with gender,anatomy,biomechanics,and neuromuscular control.Taekwondo athletes have a higher incidence of ACL injury than athletes from other sports.Objective:This study aimed to determine the biomechanical gender differences and mechanism of taekwondo athletes with ACL injury.Methods:A total of 28 taekwondo athletes(aged 14–19 years)were randomly selected and grouped by gender.Feet high floor,one foot high floor,and single leg squat were analyzed by a Vicon motion analysis system and Kistler 3D force platform for action.The knee joint angle and ground force were evaluated.Results:Results demonstrated biomechanical differences in knee joint between male and female athletes.Conclusion:ACL injury in taekwondo female athletes indicated the biomechanical mechanism of the knee joint,and it can be prevented by neuromuscular control training.

Extra-Articular Stabilization of the Canine Cranial Cruciate Ligament Injury Using Arthrex Corkscrew and FASTak Anchors

The objective of this study was to evaluate the long-term outcome in dogs with cranial cruciate ligament injury that were repaired with an Arthrex Corkscrew or FASTak bone anchor and Fiberwire placed at near isometric points of the stifle. A retrospective study (2006-2010) was conducted by reviewing clinical records of dogs treated for cranial cruciate ligament injury with an extra-articular repair method using anchors preloaded with Fiberwire. A questionnaire was given to owners for evaluation of their dog’s performance prior to surgery and at time of follow-up with a minimum of 12 months post-operative. Owner assessment was rated using a visual analogue scale. Completed questionnaires from 34 owners were received. The mean time to follow up was 27.5 months. Owner assessment of their dog prior to surgery versus at the time of follow up were considered significant (P < 0.001) in regards to quality of life, willingness to play voluntarily, activity level, stiffness at the beginning and end of the day, lameness in the surgical limb, and pain while walking on the surgical limb. These results indicate that extra-articular stabilization with Arthrex Corkscrew and FASTak anchors placed at near isometric sites are adequate repair methods for cranial cruciate ligament rupture.

Lateral femoral tunnel preparation and graft fixation for anterior cruciate ligament reconstruction–A discussion

This article provides a discussion and commentary around the recent advances in arthroscopic anterior cruciate ligament reconstruction(ACLR),with a focus on the aspects of lateral femoral tunnel preparation and graft fixation techniques.The paper explores and comments on a recently published review by Dai et al,titled"Research progress on preparation of lateral femoral tunnel and graft fixation in ACLR",while providing insight into its relevance within the field of ACLR,and recommendations for future research.

Research Progress of Anterior Cruciate Ligament Reconstruction under Arthroscopy

As an important means to treat anterior cruciate ligament (ACL) injury, the reconstruction technology under arthroscopy has made remarkable progress in recent years, evolving gradually from the early traditional open surgery to the minimally invasive surgery under full arthroscopy. At present, it is widely used. Different graft choices (such as autologous hamstring, peroneus longus, artificial tendon, and allogeneic tendon, etc.) and fixation methods (such as metal suspension fixation, interference screw, etc.) have their own characteristics. However, this technology still faces some challenges, such as postoperative complications and the long-term stability of the graft. In terms of future trends, it will develop in a more accurate and personalized direction. New materials and technologies are expected to emerge continuously to improve the surgical effect and the rehabilitation quality of patients, providing stronger support for clinical application and research. This article will conduct a comprehensive review from aspects such as surgical methods, graft selection, fixation methods, ligamentization of the graft, challenges faced, and future trends in ACL reconstruction surgery.

In vitro performance of a biodegradable zinc alloy adjustable-loop cortical suspension fixation for anterior cruciate ligament reconstruction

Anterior cruciate ligament(ACL)injuries of the knee are one of the most common and serious athletic injuries.The widely used cortical suspension fixation buttons for ligament reconstruction are permanent implants,particularly those made from conventional steel or titanium alloys.In this study,a biodegradable Zn-0.45Mn-0.2Mg(ZMM42)alloy with the yield strength of 300.4 MPa and tensile strength of 329.8 MPa was prepared through hot extrusion.The use of zinc alloys in the preparation of cortical suspension fixation buttons was proposed for the first time.After 35 d of immersion in simulated body fluids,the ZMM42 alloy fixation buttons were degraded at a rate of 44μm/a,and the fixation strength was retained(379.55 N)in the traction loops.Simultaneously,the ZMM42 alloy fixation buttons exhibited an increase in MC3T3-E1 cell viability and high antibacterial activity against Escherichia coli and Staphylococcus aureus.These results reveal the potential of biodegradable zinc alloys for use as ligament reconstruction materials and for developing diverse zinc alloy cortical suspension fixation devices.

Arthroscopic M-shaped suture fixation for tibia avulsion fracture of posterior cruciate ligament:A modified technique and case series

BACKGROUND Tibial avulsion fractures of the posterior cruciate ligament(PCL)are challenging to treat and compromise knee stability and function.Traditional open surgery often requires extensive soft tissue dissection,which may increase the risk of morbidity.In response to these concerns,arthroscopic techniques have been evolving.The aim of this study was to introduce a modified arthroscopic tech-nique utilizing an M-shaped suture fixation method for the treatment of tibial avulsion fractures of the PCL and to evaluate its outcomes through a case series.AIM To evaluate the effects of arthroscopic M-shaped suture fixation on treating tibia avulsion fractures of the PCL.METHODS We developed a modified arthroscopic M-shaped suture fixation technique for tibia avulsion fractures of the PCL.This case series included 18 patients who underwent the procedure between January 2021 and December 2022.The patients were assessed for range of motion(ROM),Lysholm score and International knee documentation committee(IKDC)score.Postoperative complications were also recorded.RESULTS The patients were followed for a mean of 13.83±2.33 months.All patients showed radiographic union.At the final follow-up,all patients had full ROM and a negative posterior drawer test.The mean Lysholm score significantly improved from 45.28±8.92 preoperatively to 91.83±4.18 at the final follow-up(P<0.001),and the mean IKDC score improved from 41.98±6.06 preoperatively to 90.89±5.32 at the final follow-up(P<0.001).CONCLUSION The modified arthroscopic M-shaped suture fixation technique is a reliable and effective treatment for tibia avulsion fractures of the PCL,with excellent fracture healing and functional recovery.

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.

Anterior cruciate ligament reconstruction:Effect of graft tunnel position on early to mid-term clinical outcomes

BACKGROUND Patient reported outcome measures(PROMs)can be used to assess knee function following anterior cruciate ligament(ACL)reconstruction.Intra-operatively,femoral and tibial tunnels are created to accommodate the new ACL graft.It is postulated that there is an optimum position and orientation of these tunnels and that outcomes from this procedure are affected by their position.AIM To evaluate the influence of graft tunnel position on early to mid-term clinical outcomes following ACL reconstruction.METHODS Six PROMs were collected following ACL reconstruction which included the Knee Injury and Osteoarthritis Outcome Score(KOOS),International Knee Documentation Committee,Lysholm,Tegner,EuroQol-5 Dimension-5 level,and Short Form 12-item Health Survey.A total of 8 radiological parameters were measured from post-operative X-rays relating to graft tunnel positions.This data was analysed to assess for any correlations between graft tunnel position and postoperative PROMs.RESULTS A total of 87 patients were included in the study with a mean post-operative follow-up of 2.3 years(range 1 to 7 years).Posterior position of tibial tunnel was associated with improved KOOS quality of life(rho=0.43,P=0.002)and EQ-5D VAS(rho=0.36,P=0.010).Anterior position of EndoButton femoral tunnel was associated with an improved EQ-5D index(rho=-0.38,P=0.028).There were no other significant correlations between any of the other radiological parameters and PROM scores.CONCLUSION Overall,graft tunnel position had very little correlation with clinical outcomes following ACL reconstruction.A few(posterior)tibial tunnel and(anterior)EndoButton femoral tunnel measurements were associated with better PROMs.

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.

Analysis of the Application of Sports Medicine Ultrasound in the Rehabilitation of Anterior Talofibular Ligament Injury

Objective: To explore the application effect of sports medicine ultrasound in the rehabilitation treatment of anterior talofibular ligament injury. Methods: 36 patients who visited our hospital from January 2020 to September 2023 were selected as research subjects and randomly divided into the study group (18 cases) and the control group (18 cases). The control group adopted routine examination and rehabilitation training, and the study group adopted sports medicine ultrasound and rehabilitation training. The ankle function scores and daily living ability of the two groups were compared before treatment and 9 weeks after treatment. Results: There was no statistically significant difference between the study group and the control group in terms of ankle function scores and ability to perform activities of daily living before treatment (P > 0.05), but the difference was statistically significant after treatment (P < 0.05). Conclusion: Ultrasound can be used as a supplement to magnetic resonance imaging (MRI) of the ankle joint for diagnosing anterior talofibular ligament injury;ultrasound can show the location, distance, and degree of tear of the anterior talofibular ligament rupture and accurately predict muscle atrophy around the ankle joint;ultrasound combined with computed tomography (CT) can better determine the type of intra-articular fracture of the talar subtalar joint, and guide the choice of surgical timing. In addition, ultrasound can be used to determine the severity of peroneal muscle atrophy, assess the progress of early postoperative functional exercise, and guide personalized rehabilitation programs.

Hamstring autograft utilization in reconstructing anterior cruciate ligament:Review of harvesting techniques,graft preparation,and different fixation methods

Rupture of the anterior cruciate ligament(ACL)is a common orthopedic injury.Various graft options are available for the reconstruction of ruptured ACL.Using the hamstring muscle as an autograft was first described in 1934,and it remains a commonly harvested graft for ACL reconstruction.Hamstring autografts can be harvested using the traditional anteromedial approach or the newer posteromedial technique.An isolated semitendinosus tendon can be used or combined with the gracilis tendon.There are numerous methods for graft fixation,such as intra-tunnel or extra-tunnel fixation.This comprehensive review discusses the different hamstring muscle harvesting techniques and graft preparation options and fixation methods.It provides a comprehensive overview for choosing the optimal surgical technique when treating patients.

Principles of postoperative anterior cruciate ligament rehabilitation

It is known that anterior cruciate ligament(ACL) reconstruction needs to be combined with detailed postoperative rehabilitation in order for patients to return to their pre-injury activity levels, and that the rehabilitation process is as important as the reconstruction surgery. Literature studies focus on how early in the postoperative ACL rehabilitation period rehabilitation modalities can be initiated. Despite the sheer number of studies on this topic, postoperative ACL rehabilitation protocols have not been standardized yet. Could common, "ossified" knowledge or modalities really prove themselves in the literature? Could questions such as "is postoperative brace use really necessary?", "what are the benefits of early restoration of the range of motion(ROM)?", "to what extent is neuromuscular electrical stimulation(NMES) effective in the protection from muscular atrophy?", "how early can proprioception training and open chain exercises begin?", "should strengthening training start in the immediate postoperative period?" be answered for sure? My aim is to review postoperative brace use, early ROM restoration, NMES, proprioception, open/closed chain exercises and early strengthening, which are common modalities in the very comprehensive theme of postoperative ACLrehabilitation, on the basis of several studies(Level of Evidence 1 and 2) and to present the commonly accepted ways they are presently used. Moreover, I have presented the objectives of postoperative ACL rehabilitation in tables and recent miscellaneous studies in the last chapter of the paper.

Therapeutic effect of two methods on avulsion fracture of tibial insertion of anterior cruciate ligament

BACKGROUND The tibial stop of anterior cruciate ligament(ACL) is fan-shaped and attached to the medial groove in front of the intercondylar spine,which is located between the anterior horn of the medial and lateral meniscus.The incidence of this fracture is low previously reported,which is common in children and adolescents.With the increase of sports injury and traffic injury and the deepening of understanding,it is found that the incidence of the disease is high at present.AIM To explore the difference between open reduction and internal fixation with small incision and high-intensity non-absorbable suture under arthroscopy in the treatment of tibial avulsion fracture of ACL.METHODS Seventy-six patients with tibial avulsion fracture of anterior cruciate ligament diagnosed and treated in Guanyun County People’s Hospital from April 2018 to June 2020 were retrospectively analyzed.According to the surgical methods,they were divided into group A(40 cases) and group B(36 cases).Patients in group A were treated with arthroscopic high-strength non-absorbable suture,and patients in group B were treated with small incision open reduction and internal fixation.The operation time,fracture healing time,knee joint activity and functional score before and after operation,and surgical complications of the two groups were compared.RESULTS The operation time of group A was higher than that of group B,and the difference was statistically significant(P < 0.05);the fracture healing time of group A was compared with that of group B,and the difference was not statistically significant(P > 0.05);The knee joint function activity was compared between two groups before operation,3 mo and 6 mo after operation,and the difference was not statistically significant(P > 0.05);the knee joint function activity of group A and group B at 3 mo and 6 mo after operation was significantly higher than that before operation(P < 0.05);the limp,support,lock,instability,swelling,upstairs,squatting,pain and Lysholm score were compared between the two groups before and 6 mo after operation,and the difference was not statistically significant(P > 0.05);the scores of limp,support,lock,instability,swelling,upstairs,squatting,pain and Lysholm in group A and group B at 6 mo after operation were significantly higher than those before operation(P > 0.05);the surgical complication rate of group A was 2.63%,which was lower than 18.42% of group B,and the difference was statistically significant(P > 0.05).CONCLUSION Both small incision open reduction and internal fixation and arthroscopic high-strength nonabsorbable sutures can achieve good results in the treatment of anterior cruciate ligament tibial avulsion fractures.The operation time of arthroscopic high-strength non-absorbable sutures is slightly longer,but the complication rate is lower.

Surgical treatment for a combined anterior cruciate ligament and posterior cruciate ligament avulsion fracture: A case report

BACKGROUND Independent avulsion fractures with anterior cruciate ligament(ACL)or posterior cruciate ligament(PCL)attachment are relatively common among tibial intercondylar eminence fractures,and their postoperative outcomes are generally favorable.Conversely,huge avulsion fractures of the intercondylar eminence containing the attachment site of both the ACL and the PCL are extremely rare,and the reported clinical outcomes are poor.CASE SUMMARY We describe a 30-year-old Japanese male's huge avulsion fracture of the intercondylar eminence of a tibia containing the attachment site of both the ACL and PCL,together with a complete tear of the medial collateral ligament and a partial tear of both the medial and lateral menisci caused by a fall from a high place.All of these injuries were treated surgically,with anatomical reduction and stable fixation.The limb function at 1 year post-surgery was excellent(Lysholm score:100 points).CONCLUSION Although this patient's complete surgical repair was complex,it should be performed in similar cases for an excellent final clinical outcome.

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.