A follow-up study of arthroscopic combined reconstruction of anterior and posterior cruciate ligaments with allograft patellar tendon

Objective:To evaluate the therapeutic effect of combined reconstruction of anterior cruciate ligament (ACL)and posterior cruciate ligament(PCL) simultaneously by using allograft patellar tendon under arthroscopy. Methods:From May 2003 to November 2005,10 cases of ruptured ACL and PCL were fixated with compressed screws and reconstructed under arthroscopy with allograft patellar tendon simultaneously.The clinical results were evaluated according to IKDC,Lysholm,and Tegner clinical rating scales. Results:All patients were followed up for 12-30 months(mean:18 months).At the last follow-up,there was no knee extension limitation and knee flexion was between 120°and 135°,with an average of 128.38°.The Lysholm score of the 10 cases was 66.5±5.6 before operation and 89.8±3.4 at last follow up.The difference was statistically significant(P<0.01).The average Tegner activity score decreased from 6.9±1.7(range.4-9)before injury to 5.5±1.6(rang:2-9)at the follow-up (P=0.53).At the end of follow-up,IKDC score was graded as A in 4 cases(40.0%),B in 5(50.0%),and C in 1(10.0%).Of the 10 patients,8 returned to the same sports level as before injury and 2 were under the level. Conclusion:Arthroscopic combined reconstruction of ACL and PCL with allograft patellar tendon has the advantages of minimal trauma in surgery and reliable satisfactory outcome.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Regeneration of the anterior cruciate ligament:Current strategies in tissue engineering

Recent advancements in the field of musculoskeletaltissue engineering have raised an increasing interest in the regeneration of the anterior cruciate ligament(ACL). It is the aim of this article to review the current research efforts and highlight promising tissue engineering strategies. The four main components of tissue engineering also apply in several ACL regeneration research efforts. Scaffolds from biological materials, biodegradable polymers and composite materials are used. The main cell sources are mesenchymal stem cells and ACL fibroblasts. In addition, growth factors and mechanical stimuli are applied. So far, the regenerated ACL constructs have been tested in a few animal studies and the results are encouraging. The different strategies, from in vitro ACL regeneration in bioreactor systems to bio-enhanced repair and regeneration, are under constant development. We expect considerable progress in the near future that will result in a realistic option for ACL surgery soon.

Arthroscopic Reconstruction of the Posterior Cruciate Ligament with a Ligament-advanced Reinforcement System and Hamstring Tendon Autograft:A Retrospective Study

Objective:Both ligament-advanced reinforcement system(LARS)and hamstring tendon autograft can serve as grafts for posterior cruciate ligament(PCL)reconstruction.However,few studies have compared the effectiveness of these two approaches.This study therefore aimed to compare the clinical efficacy of arthroscopic reconstruction of the PCL using either the LARS or hamstring tendon autograft.Methods:A total of 36 patients who underwent PCL reconstruction were retrospectively analyzed.Within this cohort,15 patients received a reconstruction using the LARS(LARS group)and 21 using the hamstring tendon autograft(HT group).Results:The pre-and post-operative subjective scores and knee stability were evaluated and the patients were followed up for a period of 2 to 10.5 years(4.11±2.0 years on average).The last follow-up showed that functional scores and knee stability were significantly improved in both groups(P<0.05).Six months after operation,Lysholm scores and IKDC subjective scores were higher in the LARS group than in the HT group(P<0.05).Nonetheless,the last follow-up showed no significant differences in the functional scores or the posterior drawer test between the two groups(P>0.05).In the LARS and HT groups,12 and 9 patients,respectively exhibited KT1000 values<3 mm,with the difference being statistically significant(P<0.05).In the HT group,the diameter of the four-strand hamstring tendon was positively correlated with height(P<0.05),which was 7.37±0.52 mm in males and 6.50±0.77 mm in females(P<0.05).Conclusion:Both LARS and hamstring tendon approaches achieved good efficacy for PCL reconstruction,but patients in the LARS group exhibited faster functional recovery and better knee stability in the long term.LARS is especially suitable for those who hope to resume activities as early as possible.

Effect of suspension training on neuromuscular function, postural control, and knee kinematics in anterior cruciate ligament reconstruction patients

BACKGROUND Suspension training(SET)is a method of neuromuscular training that enables the body to carry out active training under unstable support through a suspension therapy system.However,there have been few reports in the literature on the application of SET to anterior cruciate ligament reconstruction(ACLR)patients.It is not clear what aspects of the patient's function are improved after SET.AIM To investigate the effect of SET on the neuromuscular function,postural control,and knee kinematics of patients after ACLR surgery.METHODS Forty participants were randomized to an SET group or a control group.The SET group subjects participated in a SET protocol over 6 wk.The control group subjects participated in a traditional training protocol over 6 wk.Isokinetic muscle strength of the quadriceps and hamstrings,static and dynamic posture stability test,and relative translation of the injured knee were assessed before and after training.RESULTS The relative peak torque of the quadriceps and hamstrings in both groups increased significantly(P<0.001),and the SET group increased by a higher percentage than those in the control group(quadriceps:P=0.004;hamstrings:P=0.011).After training,both groups showed significant improvements in static and dynamic posture stability(P<0.01),and the SET group had a greater change than the control group(P<0.05).No significant improvement on the relative translation of the injured knee was observed after training in either group(P>0.05).CONCLUSION Our findings show that SET promotes great responses in quadriceps and hamstring muscle strength and balance function in ACLR patients.

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.

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.

Enhancing the Surface Properties of a Bioengineered Anterior Cruciate Ligament Matrix for Use with Point-of-Care Stem Cell Therapy

We have previously developed a poly(L-lactic)acid(PLLA)bioengineered anterior cruciate ligament(ACL)matrix that has demonstrated enhanced healing when seeded with primary ACL cells prior to implantation in a rabbit model,as compared with the matrix alone.This suggests that improving cell adhesion on the matrix may beneficially affect the healing response and long-term performance of the bioengineered ACL matrix.One regenerative engineering approach involves enhancing the surface properties of the matrix to support cell adhesion and growth in combination with point-of-care stem cell therapy.Herein,we studied the cell adhesion properties of PLLA braided microfiber matrices enhanced through the physical adsorption of fibronectin and air plasma treatment.We evaluated the kinetics and binding efficiency of fibronectin onto matrices at three time points and three fibronectin concentrations.Incubating the matrix for 120 min in a solution of 25 lgmL1 fibronectin achieved the greatest binding efficiency to the matrix and cellular adhesion.Exposing the matrices to air plasma treatment for 5 min before fibronectin adsorption significantly enhanced the cell adhesion of rabbit bone marrow-derived mesenchymal stem cells(R-BMMSCs)24 h post cell seeding.Finally,cellular proliferation was monitored for up to 21 d,the matrices were exposed to air plasma treatment,and fibronectin adsorption was found to result in enhanced cell number.These findings suggest that exposure to air plasma treatment and fibronectin adsorption enhances the cellular adhesion of PLLA braided microfiber matrices and may improve the clinical efficacy of the matrix in combination with point-of-care stem cell therapies.

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.

CARTILAGE- LIKE PHENOMENON IN THE ANTERIOR CRUCIATE LIGAMENT

Objective. To detect histological characteristic of anterior cruciate ligament (ACL) and medial collateral ligament (MCL). Methods. In each of 20 skeletally mature male mongrels and 4 men, the ACL and MCL were examined by standard hematoxylin- eosin procedure and toluidine blue staining for histologic observation. Results. The fibroblasts in medial collateral are elongated to spindle shape and aligned in a row between the bundles of collagenous fibers. Toluidine blue staining is negative. The anterior cruciate ligament demonstrated more heterogenous cell types and arrangement. It had three major cell forms:spindle, round and ovoid type, which were shorter but greater than the cells in medial collateral ligament. Toluidine blue staining was positive in anterior cruciate ligament. Most cells in anterior cruciate ligament were enclosed within lacunae. Conclusion. This study suggests that the ACL has different histological characteristics from MCL, and is more cartilage- like in nature.