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.

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.

Evaluation of Functional and Radiological Outcome of Arthroscopic-Assisted Anatomical Coracoclavicular (CC) and Acromioclavicular (AC) Ligament Reconstruction in Chronic AC Joint Dislocation

Introduction: Acromioclavicular (AC) joint dislocation is a common shoulder injury, comprising 9% - 12% of shoulder girdle injuries. Optimal management remains challenging, with treatment decisions guided by the Rockwood classification system. Controversies surround grade III injuries, necessitating further classification. Non-operative treatment has shown favorable outcomes, while surgical interventions vary. Anatomical coracoclavicular reconstruction (ACCR) has demonstrated biomechanical advantages over traditional methods. Arthroscopic techniques offer advantages, minimizing deltoid detachment and allowing concurrent pathology identification. This study evaluates the outcomes of arthroscopic-assisted ACCR in chronic AC joint dislocation. Surgical Technique: Arthroscopic-assisted ACCR involves meticulous portal placement, tendon graft harvesting, diagnostic arthroscopy, and coracoid exposure. The clavicle tunnels were made to mimic the conoid and trapezoid ligament positions, using FibreTape#2 loop and Dog Bone Button for correct placement against the coracoid base, and passing the semitendinosus graft through to reconstruct the conoid ligament, reduction done and graft follow through for anatomical reconstruction. Methods: A retrospective cohort study at Hospital Kuala Lumpur analyzed 35 patients undergoing arthroscopic-assisted ACCR for Rockwood grade III - V AC joint dislocations. Inclusion criteria encompassed trauma ≥ 3 weeks prior, no prior shoulder injuries, and ≥12-month follow-up. Functional and radiological assessments utilized ASES scores and coracoclavicular distances, respectively. Statistical analysis employed descriptive statistics and logistic regression. Results: The mean age was 38.9 years (SD 11.26), and 34 of 35 patients were male. Grade IV injuries were predominant (37.1%). Waiting time for surgery averaged 234.9 days. Functional improvement was substantial postoperatively (ASES: 55.5 to 88.9). Radiological outcomes demonstrated reduced coracoclavicular distances and maintained reduction. No significant correlation was observed between injury grade and outcomes. Conclusion: Arthroscopic-assisted ACCR for chronic AC joint dislocation yields significant functional and radiological improvement, irrespective of injury grade. Waiting time for surgery exhibits minor impact on outcomes, emphasizing the procedure’s efficacy. Concomitant injuries do not impede success, highlighting the versatility of this approach in managing shoulder instability. The study contributes valuable insights into the nuanced management of chronic AC joint dislocations and supports the adoption of arthroscopic-assisted ACCR as a viable treatment option.

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.

Comparative study of the clinical efficacy of all-inside and traditional techniques in anterior cruciate ligament reconstruction

BACKGROUND Many studies have focused on the femoral tunnel technique and fixation method,but few studies have involved the tibial tunnel technique and fixation method.The all-inside technique is one of the new techniques that has been described in recent years.All-inside anterior cruciate ligament(ACL)reconstruction is based on a tibial socket instead of a full tunnel.This method has many potential advantages.AIM To compare clinical outcomes of knee ACL autograft reconstruction using allinside quadrupled semitendinosus(AIST)and traditional hamstring tendon(TBT)techniques.METHODS From January 2017 to October 2019,the clinical data of 80 patients with ACL reconstruction were retrospectively analyzed,including 67 males and 13 females.The patients had an average age of 24.3±3.1 years(age range:18-33 years).The AIST technique was used in 42 patients and the TBT technique was used in 38 patients.The time between operation and injury,operative duration,postoperative visual analogue scale(VAS)score and knee functional recovery were recorded and compared between the two groups.The International Knee Documentation Committee(IKDC)and Lysholm scoring system were used to comprehensively evaluate clinical efficacy.RESULTS Eighty patients were followed for 24-36 mo,with an average follow-up duration of 27.5±1.8 mo.There were no significant differences in the time between surgery and injury,operative duration,IKDC and Lysholm scores of the affected knee at the last follow-up evaluation between the two groups.There were significant differences in VAS scores 1 d,3 d,7 d,2 wk and 1 mo after surgery(P<0.05).There was no significant difference in VAS score at 3 mo,6 mo and 1 year after operation.CONCLUSION The efficacy of the AIST ACL reconstruction technique was comparable to the TBT technique,but the postoperative pain was less with the AIST technique.Thus,the AIST technique is an ideal treatment choice for ACL reconstruction.

Research progress on preparation of lateral femoral tunnel and graft fixation in anterior cruciate ligament reconstruction

Anterior cruciate ligament(ACL)injury is one of the most common types of sports injuries.People’s need to participate in sports and desire for a high quality of life promotes the continuous development of ACL reconstruction technology.Arthroscopic ACL reconstruction has been recognized as an effective method for the treatment of ACL injuries.This review analyses and summarizes the advantages and limitations of each surgical procedure for arthroscopic ACL reconstruction reported in the relevant literature so as to promote the future development of more relevant techniques.

Assessment of functional prognosis of anterior cruciate ligament reconstruction in athletes based on a body shape index

BACKGROUND A healthy body shape is essential to maintain athletes’sports level.At present,little is known about the effect of athletes’body shape on anterior cruciate ligament reconstruction(ACLR).Moreover,the relationship between body shape and variables such as knee joint function after operation and return to the field has not been well studied.AIM To verify the relationship between a body shape index(ABSI)and the functional prognosis of the knee after ACLR in athletes with ACL injuries.METHODS We reviewed 76 athletes with unilateral ACL ruptures who underwent ACLR surgery in the First Hospital of Shanxi Medical University between 2017 and 2020,with a follow-up period of more than 24 mo.First,all populations were divided into a High-ABSI group(ABSI>0.835,n=38)and a Low-ABSI group(ABSI<0.835,n=38)based on the arithmetic median(0.835)of ABSI values.The primary exposure factor was ABSI,and the outcome indicators were knee function scores as well as postoperative complications.The correlation between ABSI and postoperative knee function scores and postoperative complications after ACLR were analyzed using multifactorial logistic regression.RESULTS The preoperative knee function scores of the two groups were similar.The surgery and postoperative rehabilitation exercises,range of motion(ROM)compliance rate,Lysholm score,and Knee Injury and Osteoarthritis Outcome Score of the two groups gradually increased,whereas the quadriceps atrophy index gradually decreased.The knee function scores were higher in the Low-ABSI group than in the High-ABSI group at the 24-mo postoperative follow-up(P<0.05).In multifactorial logistic regression,ABSI was a risk factor of low knee joint function score after surgery,specifically low ROM scores(odds ratio[OR]=1.31,95%confidence interval[CI][1.10-1.44];P<0.001),low quadriceps atrophy index(OR=1.11,95%CI[0.97-1.29];P<0.05),low Lysholm scores(OR=2.34,95%CI[1.78-2.94];P<0.001),low symptoms(OR=1.14,95%CI[1.02-1.34];P<0.05),low activity of daily living(OR=1.34,95%CI[1.18-1.65];P<0.05),low sports(OR=2.47,95%CI[1.78-2.84];P<0.001),and low quality of life(OR=3.34,95%CI[2.88-3.94];P<0.001).ABSI was also a risk factor for deep vein thrombosis of the lower limb(OR=2.14,95%CI[1.88-2.36],P<0.05]and ACL recurrent rupture(OR=1.24,95%CI[0.98-1.44],P<0.05)after ACLR.CONCLUSION ABSI is a risk factor for the poor prognosis of knee function in ACL athletes after ACLR,and the risk of poor knee function after ACLR,deep vein thrombosis of lower limb,and ACL recurrent rupture gradually increases with the rise of ABSI.

Combined medial patellofemoral ligament and medial patellotibial ligament reconstruction in recurrent patellar instability:A systematic review and meta-analysis

BACKGROUND The medial patellofemoral ligament(MPFL),along with the medial patellotibial ligament(MPTL)and medial patellomeniscal ligament,aid in the stabilization of the patellofemoral joint.Although the MPFL is the primary stabilizer and the MPTL is a secondary limiter,this ligament is critical in maintaining joint stability.There have been few studies on the combined MPFL and MPTL reconstruction and its benefits.AIM To look into the outcomes of combined MPFL and MPTL reconstruction in frequent patellar instability.METHODS By May 8,2022,four electronic databases were searched:Medline(PubMed),Scopus,Web of Science,and Google Scholar.General keywords such as"patellar instability,""patellar dislocation,""MPFL,""medial patellofemoral ligament,""MPTL,"and"medial patellotibial ligament"were co-searched to increase the sensitivity of the search.RESULTS The pooled effects of combined MPFL and MPTL reconstruction for Kujala score(12-mo followup)and Kujala score(24-mo follow-up)were positive and incremental,according to the findings of this meta-analysis.The mean difference between the Cincinnati scores was also positive,but not statistically significant.The combination of the two surgeries reduces pain.According to cumulative meta-analysis,the trend of pain reduction in various studies is declining over time.CONCLUSION The combined MPFL and MPTL reconstruction has good clinical results in knee function and,in addition to providing good control to maintain patellofemoral joint balance,the patient's pain level decreases over time,making it a valid surgical method for patella stabilization.

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.

Influence of screw length and diameter on tibial strain energy density distribution after anterior cruciate ligament reconstruction

Postoperative tunnel enlargement has been frequently reported after anterior cruciate ligament（ACL）reconstruction.Interference screw,as a surgical implant in ACL reconstruction,may influence natural loading transmission and contribute to tunnel enlargement.The aims of this study are（1）to quantify the alteration of strain energy density（SED）distribution after the anatomic single-bundle ACL reconstruction;and（2）to characterize the influence of screw length and diameter on the degree of the SED alteration.A validated finite element model of human knee joint was used.The screw length ranging from 20 to 30 mm with screw diameter ranging from 7 to 9 mm were investigated.In the post-operative knee,the SED increased steeply at the extra-articular tunnel aperture under compressive and complex loadings,whereas the SED decreased beneath the screw shaft and nearby the intra-articular tunnel aperture.Increasing the screw length could lower the SED deprivation in the proximal part of the bone tunnel;whereas increasing either screw length or diameter could aggravate the SED deprivation in the distal part of the bone tunnel.Decreasing the elastic modulus of the screw could lower the bone SED deprivation around the screw.In consideration of both graft stability and SED alteration,a biodegradable interference screw with a long length is recommended,which could provide a beneficial mechanical environment at the distal part of the tunnel,and meanwhile decrease the bone-graft motion and synovial fluid propagation at the proximal part of the tunnel.These findings together with the clinical and histological factors could help to improve surgical outcome,and serve as a preliminary knowledge for the following study of biodegradable interference screw.

Current and future of anterior cruciate ligament reconstruction techniques

In recent years,anterior cruciate ligament(ACL)reconstruction has generally yielded favorable outcomes.However,ACL reconstruction has not provided satisfactory results in terms of the rate of returning to sports and prevention of osteoarthritis(OA)progression.In this paper,we outline current techniques for ACL reconstruction such as graft materials,double-bundle or single-bundle reconstruction,femoral tunnel drilling,all-inside technique,graft fixation,preservation of remnant,anterolateral ligament reconstruction,ACL repair,revision surgery,treatment for ACL injury with OA and problems,and discuss expected future trends.To enable many more orthopedic surgeons to achieve excellent ACL reconstruction outcomes with less invasive surgery,further studies aimed at improving surgical techniques are warranted.Further development of biological augmentation and robotic surgery technologies for ACL reconstruction is also required.

Degradability of absorbable sutures in tendon grafts following anterior cruciate ligament reconstruction

Objective To observe the degradability of absorbable sutures in tendon grafts and the histology of tendon healing in a rabbit model.Methods Semitendinosus tendons were harvested from 15 healthy adult New Zealand rabbits in this study.

Multiphasic bone-ligament-bone integrated scaffold enhances ligamentization and graft-bone integration after anterior cruciate ligament reconstruction

The escalating prevalence of anterior cruciate ligament(ACL)injuries in sports necessitates innovative strategies for ACL reconstruction.In this study,we propose a multiphasic bone-ligament-bone(BLB)integrated scaffold as a potential solution.The BLB scaffold comprised two polylactic acid(PLA)/deferoxamine(DFO)@mesoporous hydroxyapatite(MHA)thermally induced phase separation(TIPS)scaffolds bridged by silk fibroin(SF)/connective tissue growth factor(CTGF)@Poly(L-lactide-co-ε-caprolactone)(PLCL)nanofiber yarn braided scaffold.This combination mimics the native architecture of the ACL tissue.The mechanical properties of the BLB scaffolds were determined to be compatible with the human ACL.In vitro experiments demonstrated that CTGF induced the expression of ligament-related genes,while TIPS scaffolds loaded with MHA and DFO enhanced the osteogenic-related gene expression of bone marrow stem cells(BMSCs)and promoted the migration and tubular formation of human umbilical vein endothelial cells(HUVECs).In rabbit models,the BLB scaffold efficiently facilitated ligamentization and graft-bone integration processes by providing bioactive substances.The double delivery of DFO and calcium ions by the BLB scaffold synergistically promoted bone regeneration,while CTGF improved collagen formation and ligament healing.Collectively,the findings indicate that the BLB scaffold exhibits substantial promise for ACL reconstruction.Additional investigation and advancement of this scaffold may yield enhanced results in the management of ACL injuries.

Effects of higher femoral tunnels on clinical outcomes,MRI,and second-look findings in double-bundle anterior cruciate ligament reconstruction with a minimal 5-year follow-up

Background:To perform anatomical anterior cruciate ligament reconstruction(ACLR),tunnels should be placed relatively higher in the femoral anterior cruciate ligament(ACL)footprint based on the findings of direct and indirect femoral insertion.But the clinical results of higher femoral tunnels(HFT)in double-bundle ACLR(DB-ACLR)remain unclear.The purpose was to investigate the clinical results of HFT and lower femoral tunnels(LFT)in DB-ACLR.Methods:From September 2014 to February 2016,83 patients who underwent DB-ACLR and met the inclusion and exclusion criteria were divided into HFT-ACLR(group 1,n=37)and LFT-ACLR(group 2,n=46)according to the position of femoral tunnels.Preoperatively and at the final follow-up,clinical scores were evaluated with International Knee Documentation Committee(IKDC),Tegner activity,and Lysholm score.The stability of the knee was evaluated with KT-2000,Lachman test,and pivot-shift test.Cartilage degeneration grades of the International Cartilage Repair Society(ICRS)were evaluated on magnetic resonance imaging(MRI).Graft tension,continuity,and synovialization were evaluated by second-look arthroscopy.Return-to-sports was assessed at the final follow-up.Results:Significantly better improvement were found for KT-2000,Lachman test,and pivot-shift test postoperatively in group 1(P>0.05).Posterolateral bundles(PL)showed significantly better results in second-look arthroscopy regarding graft tension,continuity,and synovialization(P<0.05),but not in anteromedial bundles in group 1.At the final follow-up,cartilage worsening was observed in groups 1 and 2,but it did not reach a stastistically significant difference(P>0.05).No statistically significant differences were found in IKDC subjective score,Tegner activity,and Lysholm score between the two groups.Higher return-to-sports rate was found in group 1 with 86.8%(32/37)vs.65.2%(30/46)in group 2(P=0.027).Conclusion:The HFT-ACLR group showed better stability results,better PL,and higher return-to-sports rate compared to the LFT-ACLR group.

A new method of anterior talofibular ligament reconstruction:Arthroscopically artificial ligament reconstruction with tensional remnant-repair

Purpose:To investigate the clinical effects of arthroscopically artificial ligament reconstruction with tensional remnant-repair in patients who are obese,and/or with demand for highly intensive sports,and/or with poor-quality ligament remnants.Methods:A retrospective case series study was performed on patients treated by arthroscopically anterior talofibular ligament(ATFL)reconstruction with tensional remnant repair technique from January 2019 to August 2021.General data,including demographics,surgical time,and postoperative adverse events,were recorded.The American Orthopaedic Foot and Ankle Society score(AOFAS),foot and ankle ability measure(FAAM),visual analog scale(VAS),and anterior talar translation were measured preoperatively and at 6 weeks,3 months,and 2 years postoperatively.Ultrasonography examination was performed preoperatively and 2 years postoperatively to evaluate the ATFL.Data were analyzed using SPSS 19.0.F test was used to analyze the pre-and postoperative VAS,FAAM,and AOFAS scores.The significance was set at p<0.05.Results:There were 20 males and 10 females among the patients with a mean age of(30.71±5.81)years.The average surgical time was(40.21±8.59)min.No adverse events were observed after surgery.At 2 years postoperatively,the anterior talar translation test showed grade 0 laxity in all patients.VAS score significantly decreased from preoperatively to 6 weeks,3 months,and 2 years postoperatively(p<0.001).Improvement of FAAM score and the AOFAS score from preoperatively to 6 weeks,3 months,and 2 years postoperatively was statistically significant(p<0.001).At 3 months postoperatively,most patients(23/30)could return to their pre-injured activities of daily living status.At 2 years postoperatively,all patients were able to return to their pre-injured activities of daily living status,and almost every patient(18/19)who expected highly intensive sports returned to sports with only 1 obese patient failing to achieve the goal.The ultrasonography examination at 2 years postoperatively showed that there was a linear band structure of soft tissue on the tension-rich fiber tape image from the fibular to the talar attachment sits of ATFL.Conclusion:The novel arthroscopically artificial ligament reconstruction with tensional remnant-repair technique for ATFL achieved satisfactory clinical outcomes in the short and medium term after operation,and allowed early return to pre-injured activities,which could be a reliable option for patients with chronic lateral ankle instability.

Factors affecting proprioceptive recovery after anterior cruciate ligament reconstruction

Background Proprioception plays an important role in knee movements. Since there are controversies surrounding the overall recovery time of proprioception following surgery, it is necessary to define the factors affecting proprioceptive recovery after anterior cruciate ligament （ACL） reconstruction and to investigate the relationship between proprioception and muscle strength. Methods A total of 36 patients who had their ACL reconstructed with a semitendinosus/gracilis graft （reconstructed group： 6 months post-surgery） and 13 healthy adults without any knee injury （control group） were included in the study. Knee proprioception was evaluated with a passive reproduction test. Isokinetic strength was measured using the Biodex System. Statistical analysis was used to compare proprioception of the reconstructed group versus the control group, and to define causal factors, including sex, hamstring/quadriceps ratio, and the course of injury before reconstruction, We also investigated the correlation between the passive reproduction error and quadriceps index. Results There was a significant difference in proprioception between the reconstructed and control groups （P 〈0.05）. When the course of injury before reconstruction was less than 4 months, there was a linear correlation with proprioception 6 months after the operation （r=0.713, P 〈0.05）. There was a positive correlation between post-surgery proprioception and the quadriceps index at 6 months post-surgery. Conclusions Impaired knee proprioception is observed 6 months after ACL reconstruction. Within 4 months of injury, early undertaking of reconstruction is associated with better proprioception outcome. Patients with enhanced proprioception have a better quadriceps index.

Are failures of anterior cruciate ligament reconstruction associated with steep posterior tibial slopes？ A case control study

Background Recently, increasing number of literature has identified the posterior tibial slope （PTS） as one of the risk factors of primary anterior cruciate ligament （ACL） injury. However, few studies concerning the association between failure of ACL reconstruction （ACLR） and PTS have been published. The objective of this study was to explore the association between the failure of ACLR and PTS at a minimum of two years follow-up. Methods Two hundred and thirty eight eligible patients from June 2009 to October 2010 were identified from our database. A total of 20 failure cases of ACLR and 20 randomly selected controls were included in this retrospective study. The demographic data and the results of manual maximum side-to-side difference with KT-1000 arthrometer at 30°of knee flexion and pivot-shift test before the ACLR and at the final follow-up were collected. The medial and lateral PTSs were measured using the magnetic resonance imaging （MRI） scan, based on Hudek＇s measurement. A comparison of PTS between the two groups was performed. Results The overall failure rate of the present study was 8.4%. Of the 40 participants, the mean medial PTS was 4.1°±3.2°and the mean lateral PTS was 4.6°±2.6°. The medial PTS of the ACLR failure group was significantly steeper than the control group （3.5°±2.5° vs. 6.1°±2.1°, P=0.000）. Similarly, the lateral PTS of the ACLR failure group was significantly steeper than the control group （2.9°±2.1 °vs. 5.5°±3.0°, P=0.006）. For medial PTS ≥5°, the odds ratio of ACLR failure was 6.8 （P=0.007）; for lateral PTS ≥5°, the odds ratio of ACLR failure was 10.8 （P=0.000）. Conclusion Both medial and lateral PTS were significantly steeper in failures of ACLR than the control group. Medial or lateral PTS ≥5° was a new risk factor of ACLR failure.

Knee function after anterior cruciate ligament reconstruction with patellar or hamstring tendon： a meta-analysis

Background There is currently no consensus regarding the best graft type for anterior cruciate ligament reconstruction. Therefore, the aim of this study was to investigate the effects of patellar and hamstring tendon grafts on long-term knee function after anterior cruciate ligament reconstruction. Methods This meta-analysis was conducted according to the methodological guidelines outlined by the Cochrane Collaboration. An electronic search of the literature was performed and all trials published between January 1966 and August 2011 comparing knee function after anterior cruciate ligament reconstruction using patellar tendon grafts with knee function after reconstruction with hamstring tendon grafts were pooled. Six studies were included in the final meta-analysis. Results Anterior cruciate ligament reconstruction using hamstring tendon grafts resulted in greater pain upon kneeling than reconstruction using patellar tendon grafts （P=0.001）. However, both grafts resulted in similar levels of anterior tibial translation, and similar results regarding isokinetic extension/flexion tests, Lysholm scores, and the stair-hop test （P 〉0.05）. Conclusion Anterior cruciate ligament reconstruction using patellar or hamstring tendon grafts results in similar long-term knee function.