Chronic Anterior Cruciate Ligament Deficiency Research Articles

Dynamically tensioned ACL functional knee braces reduce ACL and meniscal strain.

The effectiveness of ACL functional knee braces to reduce meniscal and ACL strain after ACL injury or reconstruction is not well understood. A new dynamic knee tensioning brace system has been designed to apply an active stabilizing force to the knee. The ability of this system to reduce tissue strains is unknown. The purpose of this study was to test the ability of the dynamically tensioned brace to reduce strain in both the ACL and meniscus during rehabilitation activities. A combined in vivo/in silico/in vitro method was used to study three activities: gait, double leg squat, and single leg squat. Muscle forces and kinematics for each activity were derived through in vivo motion capture and applied to seven cadaveric knee specimens fitted with custom braces. Medial meniscal strain and ACL strain were measured in ACL intact, deficient and reconstructed conditions. The brace lowered peak and average meniscal strain in ACL deficient knees (P < 0.05) by an average of 1.7%. The brace was also found to lower meniscal strain in reconstructed knees (1.1%) and lower ACL strain in ACL intact (1.3%) and reconstructed knees (1.4%) (P < 0.05). This study supports the use of a brace equipped with a dynamic tensioning system to lower meniscal strain in ACL-deficient knees. Its use may help decrease the risk of subsequent meniscal tears in chronic ACL deficiency or delayed reconstruction. In ACL-intact and reconstructed knees, the brace may be beneficial in injury prophylaxis or in protecting the ACL graft following reconstruction. These results will aid clinicians make informed recommendations for functional brace use in patients with unstable knees. II.

Kinematics and arthrokinematics in the chronic ACL-deficient knee are altered even in the absence of instability symptoms.

To analyze the in vivo kinematics and arthrokinematics of chronic ACL-deficient (ACL-D) and unaffected contralateral knees during level walking and downhill running using dynamic biplane radiography. It was hypothesized that ACL-D knees would demonstrate increased anterior translation and internal rotation, and that ACL-deficiency would alter the tibiofemoral contact paths in comparison to the unaffected contralateral side. Eight participants with unilateral chronic ACL-D without instability symptoms were recruited. The contralateral unaffected knee was considered as control. Kellgren-Lawrence (K-L) grades were determined from ACL-D and unaffected knees. Dynamic knee motion was determined from footstrike through the early-stance phase (20-25% of gait cycle) using a validated volumetric model-based tracking process that matched subject-specific CT bone models to dynamic biplane radiographs. Participants performed level walking at 1.2m/s and downhill running at 2.5m/s while biplane radiographs were collected at 100 and 150 images per second, respectively. Tibiofemoral kinematics and arthrokinematics (the path of the closest contact point between articulating subchondral bone surfaces) were determined and compared between ACL-D and unaffected knees. A two-way repeated measures analysis of variance was used to identify differences between ACL-D and unaffected knees at 5% increments of the gait cycle. Anterior-posterior translations were significantly larger in ACL-D than unaffected knees during level walking (all p < 0.001) and downhill running (all p ≤ 0.022). Internal rotation showed no significant difference between ACL-D and unaffected knees during level walking and downhill running. Closest contact points on the femur in ACL-D knees were consistently more anterior in the lateral compartment during downhill running (significant from 10 to 20% of the gait cycle, all p ≤ 0.044), but not during level walking. No differences in medial compartment contact paths were identified. Half of the participants had asymmetric K-L grades, with all having worse knee OA in the involved knee. Only 2 relatively young individuals had not progressed beyond stage 1 in either knee. The results suggest that anterior translation and knee joint contact paths are altered in ACL-D knees even in the absence of instability symptoms. The clinical relevance is that ACL-D patients who do not report symptoms of instability likely still demonstrate altered knee kinematics and arthrokinematics compared to their uninvolved limb. Case-control study, Level III.

Improvement in the medial meniscus posterior shift following anterior cruciate ligament reconstruction.

Anterior cruciate ligament (ACL) reconstruction can reduce the risk of developing osteoarthritic knees. The goals of ACL reconstruction are to restore knee stability and reduce post-traumatic meniscal tears and cartilage degradation. A chronic ACL insufficiency frequently results in medial meniscus (MM) injury at the posterior segment. How ACL reconstruction can reduce the deformation of the MM posterior segment remains unclear. In this study, we evaluated the form of the MM posterior segment and anterior tibial translation before and after ACL reconstruction using open magnetic resonance imaging (MRI). Seventeen patients who underwent ACL reconstructions without MM injuries were included in this study. MM deformation was evaluated using open MRI before surgery and 3months after surgery. We measured medial meniscal length (MML), medial meniscal height (MMH), medial meniscal posterior body width (MPBW), MM-femoral condyle contact width (M-FCW) and posterior tibiofemoral distance (PTFD) at knee flexion angles of 10° and 90°. There were no significant pre- and postoperative differences during a flexion angle of 10°. At a flexion angle of 90°, MML decreased from 43.7±4.5 to 41.4±4.5mm (P<0.001), MMH from 7.5±1.4 to 6.9±1.4mm (P=0.006), MPBW from 13.1±2.0 to 12.2±1.9mm (P<0.001) and M-FCW from 10.0±1.5 to 8.5±1.5mm (P<0.001) after ACL reconstruction. The PTFD increased from 2.1±2.8 to 2.7±2.4mm after ACL reconstruction (P=0.015). ACL reconstruction affects the contact pattern between the MM posterior segment and medial femoral condyle and can reduce the deformation of the MM posterior segment in the knee-flexed position by reducing abnormal anterior tibial translation. It possibly prevents secondary injury to the MM posterior segment and cartilage that progresses to knee osteoarthritis. IV.

Anterior Cruciate Ligament Tears: Impact of Delayed Presentation on Intra-Articular Injuries

Objectives:Chronic anterior cruciate ligament (ACL) injury is associated with increased risk for meniscal and chondral injuries. The purpose of this study was to examine what intra-articular injuries occur related to the cartilage and meniscus in the setting of chronic ACL deficiency.Methods:A cross-sectional cohort study was conducted using a retrospective chart review for all patients who sustained an ACL injury and underwent reconstruction from January 1, 2009 to May 14, 2015. Demographic variables were age, gender, and BMI (Body Mass Index). Additionally, days from injury to surgery, presence of meniscus tears and presence of articular cartilage injury were recorded. Data was analyzed to determine the association between delay of surgery and cartilage or meniscus injury as well as gender, BMI and age at the time of surgery.Results:410 patients were included in this study. The average age was 27 ± 8.8 years (range of 14-59 years). 58.5% of patients had a BMI >25. 70.5% of the patients were male. 27.3% of patients were treated within 3 months of injury, 23.6% between 3-6 months, 18% between 6-12 months, 24.1% between 12-60 months, and 6.9% >60 months (Table 1). Male gender and older age were significant predictive factors for delaying ACL surgery (P < .01). Male gender was significantly associated with presence of lateral meniscus tear (LMT) (P < .001) and lateral femoral condyle (LFC) injury (P< .01). The 40+ age group was significantly more likely to have an medial femoral condyle (MFC) injury (P < .01), medial tibial plateau (MTP) injury (P < .001), lateral tibial plateau (LTP) injury (P < .01), and patellofemoral (PF) injury (P < .001) as compared to those <20 years old. Patients with BMI >25 were significantly more likely to have an MFC injury (P< .05). There was a significant correlation of medial meniscus tear (MMT) with MFC and MTP injury (P < .001, OR 4.8; P < .05, OR 2.6). There was also a significant correlation of LMT and LTP injury (P < .05, OR 2.0). An increase in the presence of MMT was seen in longer delay to time of surgery (P < .001). When compared to the < 3 months group, the 6 to < 12 months group (OR 2.1), the 12 to < 60 months group (OR 4.2) and the 60 months or greater group (OR 6.2) were more likely to have a MMT. A similar trend was seen with MFC injury (P < .001) in the 6 to < 12 months group (OR 2.7), the 12 to < 60 months group (OR 3.1), and the 60 months or greater group (OR 8.3). Presence of LTP injury and LFC injury was also significantly increased with surgical delay, but this association did not occur until 12 to < 60 months (P < .05; OR 5.6) and 60 months or greater (P < .001; OR 21.5) (Figure 1).Conclusion:Delaying ACL surgery for 6 months or longer is associated with an increased presence of medial meniscus tears and chondral injury (MFC, LFC, and LTP), with increased incidence in longer delays. This data supports not delaying surgery more than 6 months following an ACL tear to prevent the incidence of secondary meniscus tears and articular cartilage injury. In addition, particular attention should be paid to those who are older age and male gender as they are at increased risk for more severe cartilage and meniscal injuries.Table 1.Demographic Factors and Associated Meniscal and Chondral Injuries Identified in Surgerya BMIAge (years)Gender <2525 to <3030+<2020 to <3030 to <4040+MaleFemale MMT 69/138 (50.0)98/167 (58.7)46/73 (63.0)39/77 (50.6)101/187 (54.0)64/104 (61.5)27/40 (67.5) P=NS166/288 (57.6)66/121 (54.5) P=NS LMT 75/138 (54.3)98/167 (58.7)49/73 (67.1) P=NS49/77 (63.6)119/188 (63.3)58/104 (55.8)15/40 (37.5) OR, 0.3 P < 0.5187/289 (64.7) OR, 2.354/121 (44.6) P < .001 MFC Injury 25/138 (18.1)53/167 (31.7) OR, 2.122/73 (30.1) OR, 1.9 P < .0512/77 (15.6)47/188 (25.0)33/104 (31.7) OR, 2.519/40 (47.5) OR, 4.9 P < .0172/289 (24.9)40/121 (33) P=NS LFC Injury 8/138 (5.8)22/167 (13.2)9/73 (12.3) P=NS1/76 (1.3)26/188 (13.8)11/104 (10.6)2/40 (5.0) P=NS35/288 (12.1) OR, 3.25/121 (4.1) P < .05 MTP Injury 2/137 (1.5)12/167 (7.2)5/72 (6.9) P=NS1/76 (1.3)4/187 (2.1)6/104 (5.8)10/40 (25.0) OR, 25.0 P < .00119/288 (6.6)2/118 (1.7) P=NS LTP Injury 13/138 (9.4)20/167 (12.0)11/73 (15.1) P=NS2/76 (2.6)18/188 (9.6)19/104 (18.3) OR, 8.38/40 (20.0) OR, 9.2 P < .0131/288 (10.8)16/121 (13.2) P = NS PF Injury 22/138 (15.9)35/167 (21.0)21/73 (28.8) P=NS5/77 (6.5)17/188 (9.0)35/104 (33.7) OR, 7.325/40 (62.5) OR, 24.0 P < .00155/289 (19)27/121 (22.3) P=NS aValues are expressed as n (%). P < .05 considered statistically significant, OR, odds ratio; NS, not significant, OR listed for groups significantly different from comparison group. Female gender was used as the comparison group for gender.

KNEE LAXITY MEASUREMENT IN ACUTE KNEE TRAUMA AND ACL EVALUATION WITH THE ROLIMETER

The Rolimeter is an instrument that quantifies anterior knee laxity and has in previous studies showed satisfactory results regarding intra- and inter test reliability in subjects without injuries or with...

Medial Opening Wedge Proximal Tibial Osteotomy

Genu varus malalignment can lead to medial compartment overload and progression of ipsilateral compartment osteoarthritis. To slow this process, a medial opening wedge proximal tibial osteotomy (PTO) can be performed. This type of PTO is indicated in patients with genu varus malalignment and isolated medial compartment osteoarthritis of the knee, prior to or concurrent with medial compartment cartilage procedures or meniscal transplants, chronic posterolateral corner deficiency, or chronic anterior cruciate ligament deficiency. When treating ligamentous instability, a PTO can be performed in isolation, with simultaneous ligament reconstruction, or as a staged procedure with the osteotomy first, followed by ligament reconstruction if instability persists. Failure to address malalignment in cases of concurrent ligament reconstruction leads to increased stress on the graft and potential graft failure. One distinct advantage of this procedure is the ability to correct deformities in the sagittal and coronal planes. The purpose of this article was to describe our technique used to perform a medial opening wedge PTO.

The Early Results of the Reconstruction of Chronic Anterior Cruciate Ligament Deficiency with Single Tunnel-Dual-Bundle Technique and Quadruple Hamstring Autograft

Purpose: Our study retrospectively evaluates the early results of the reconstruction of anterior cruciate ligament (ACL) defficiency by single tunnel–Dual bundle technique and quadruple autogenous hamstring tendon graft. Methods: Fourteen female and 46 male patients whom with chronic instability due to ACL deficiency were included in this study. The injury mechanism was sports related injury in 45 patients and in 15 patients the injury were other causes. All of the patients were treated with Single tunnel–Dual band technique and quadruple autogenous hamstring semitendinosus (ST) and gracilis (G) tendon graft. The patients were clinically evaluated with Lachman test, pivot-shift test, anterior drawer test, Mc Murray test, Lysholm activity scale and International Knee Documentation Comittee (IKDC) Questionaire preoperatively and postoperatively and the data were recorded. Results: The average follow-up was 34.08 months (45–26 months). Both of the menisci were intact in 22 of the patients (36.6%) and meniscal lesion were present in 38 (63.3%) patients. Two of the patients with medial meniscal lesion were sutured with meniscal repair system. Also micro-fracture was performed in 4 patients with grade 3 chondral lesion in medial femoral condyle. The preoperative mean IKDC scores of 38.3 points (range 28.7–63.9) raised to 78.1 points (range 54-98.9) postoperatively and the difference was statystically significant. Conclusion: In light of the findings of our study and related literature we can comment that the mid-term results of the reconstruction of anterior cruciate ligament (ACL) defficiency by single tunnel–Dual band technique and quadruple autogeneus hamstring tendon graft with AperFix fixation system are stisfactory.

Gait modification strategies in trunk over right stance phase in patients with right anterior cruciate ligament deficiency

This study aimed to investigate the gait modification strategies of trunk over right stance phase in patients with right anterior cruciate ligament deficiency (ACL-D). Thirty-six patients with right chronic ACL-D were recruited, as well as 36 controls. A 3D optical video motion capture system was used during gait and stair ambulation. Kinematic variables of the trunk and kinematic and kinetic variables of the knee were calculated. Patients with chronic right ACL-D exhibited many significant abnormalities compared with controls. Trunk rotation with right shoulder trailing over the right stance phase was lower in all five motion patterns (P<0.05). Compared with controls, trunk posterior lean was higher from descending stairs to walking when the knee sagittal plane moment ended (P<0.01). Trunk lateral flexion to the left was higher when ascending stairs at the start of right knee coronal plane moment (P=0.01), when descending stairs at the maximal knee coronal plane moment (P<0.01), and when descending stairs at the end of the knee coronal plane moment (P=0.03). Trunk rotation with right shoulder forward was higher at the minimal knee transverse plane moment (P<0.01) and when the knee transverse plane moment ended (P<0.01); during walking, trunk rotation with right shoulder trailing was lower at other knee moments during other walking patterns (all P<0.01). In conclusion, gait modification strategies of the trunk were apparent in patients with ACL-D. These results provide new insights about diagnosis and rehabilitation of chronic ACL-D (better use of walking and stair tasks as part of a rehabilitation program).

Knee muscle activity during gait in patients with anterior cruciate ligament injury: a systematic review of electromyographic studies.

This review compared knee muscle activity between ACL-deficient (ACLD) patients and healthy controls during gait, to find out whether the available electromyography (EMG) studies support Quadriceps (Q-ceps) inhibition or hamstring facilitation during gait in ACLD patients. A systematic review was conducted to retrieve the EMG studies of knee muscles during gait in ACLD patients. Cochrane library, PubMed, Medline, Ovid, CINAHL and Science Direct databases were searched entries from 1995 through October 2014 using the terms "anterior cruciate ligament" OR "ACL", "electromyography" Or "EMG" "gait" Or "walking". Articles that assessed subjects with ACL rupture that used surface EMG to assess the knee muscle activity were included. The quality of the included papers was assessed using the Critical Appraisal Skills Programme tool for observational studies. In total, 13 studies met the inclusion criteria. Seven studies consistently found no significant difference in magnitude of activity or timing of Q-ceps muscle between the chronic ACLD patients and control subjects. Two studies on acute ACLD patients and three studies on ACLD patients with unstable knee found the significantly reduced Q-ceps activity compared to control subjects. Six studies showed the significantly greater hamstring activity, and three studies found prolonged duration of activity in ACLD patients compared to the control subjects. This review highlighted that the results of the studies are in favour of increased hamstring muscular activity. However, decreased Q-ceps activation exists in the acute stage and in ACLD patients that experience knee instability (non-copers). III.

Combined chronic anterior cruciate ligament and posterior cruciate ligament reconstruction: functional and clinical results.

Multiligamentous injury to the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL) is an uncommon but debilitating event. Patients with combined ligament injuries typically complain of painful, debilitating knee instability that restricts their sports and daily activities. The purpose of this retrospective study was to evaluate functional and clinical outcomes of patients with chronic ACL and PCL deficiency who underwent simultaneous single-stage arthroscopic reconstruction of the central pivot. Medical records of 20 consecutive patients with chronic ACL and PCL deficiency who underwent simultaneous single-stage arthroscopic reconstruction of the central pivot were retrospectively reviewed. All patients had received either an allograft (group A) or a semitendinosus-gracilis graft for ACL repair and a bone-patellar tibial-bone graft for PCL repair (group B). Functional outcomes, after the initial follow-up period at 24-month FU, were assessed with concentric isokinetic knee extensor-flexor testing at 60 and 180°/s. The secondary aim was to compare long-term clinical recovery by the administration of the IKDC (International Knee Document Committee) Knee Ligament Evaluation Form, the Lysholm Knee Scoring Scale and the Cincinnati Knee Rating Scale. The mean per cent quadriceps strength deficit in the operated as compared to the healthy knee was 13.5% in group A and 15% in group B (angular velocity 60°/s) and 13.5% in group A and 9.4% in group B (angular velocity 180°/s). The mean per cent flexor strength deficit in the operated as compared to the healthy knee was 10.4% in group A and 12.3% in group B (angular velocity 60°/s) and 12.2% in group A and 9% in group B (angular velocity of 180°/s). The flexor-quadriceps ratio was 49.4% in group A and 48.8% in group B in the healthy knee and 53.2% in group A and 53.8% in group B in the operated knee (angular velocity 60°/s) and 63.9% in group A and 60.7% in group B in the healthy knee and 65% in group A and 64.9% in group B in the operated knee (angular velocity 180°/s). Lysholm outcome was 93.9±3.9 in group A and 89.1±7.6 in group B (n.s). Cincinnati score was 89.6±7.3 in group A and 91.0±6.9 in group B (p=0.791). IKDC results were group A in six patients (60%), group B in three patients (30%) and group C in one patient (10%) in the allograft group and group A in seven patients (70%) and group B in three patients (30%) for autologous group. The results of this study suggest that one-stage arthroscopic bicruciate ligament reconstruction can restore good knee joint function. Surgical treatment should be followed by a comprehensive rehabilitation programme with specific goals, objectives and strategies, including pain management and assessment of progress in recovery of joint function and perception of knee stability. Retrospective case series, Level IV.

Three-dimensional kinematic and kinetic gait deviations in individuals with chronic anterior cruciate ligament deficient knees: a systematic review

Background: Altered joint motion that occurs in people with an anterior cruciate ligament deficient (ACLD) knee has been proposed to play a role in the initiation of knee osteoarthritis (OA), although the exact mechanism behind this is poorly understood. There is evidence that frontal plane knee motion plays a crucial role in the pathogenesis of knee OA. However, limited information exists with regards to frontal and transverse plane knee kinematics and kinetics. Purpose: We aimed to identify all relevant articles and synthesize the findings of the literature on 3D gait deviations emphasising on the frontal and transverse plane in individuals with chronic ACLD knee; those who have had the injury for 6 months or longer compared to their uninjured knee or a control group. Methods: As per the PRISMA guidelines, we searched five electronic databases from inception to 14th October 2013, with key words related to ACL, biomechanics and gait, limited to human studies only. Two independent reviewers assessed study eligibility based on predetermined inclusion/exclusion criteria and methodological quality was evaluated using the STROBE statement checklist. Results: Of the 1075 identified citations, 16 studies met the inclusion criteria. The selected studies have a small sample size (range = 20–72) and a higher number of male participants compared to women (average = 69.3% men). The participants with ACLD knee had an average age of 30.4± 8.95 years and time from injury that ranged from 6 months to more than 7.5 years. Comparing the two groups (ACLD vs. healthy controls) most studies found no kinetic or kinematic differences. However, individual studies identified the following differences during the stance phase of gait with the ACLD group exhibiting: a) greater knee abduction angle at heel strike (1 out of 3 studies); b) greater tibial external rotation (2 out of 4 studies); c) greater average knee flexion angle (6 out of 11 studies); lower knee adduction moment (1 out of 3 studies) and e) greater knee extensor moment at heel strike (1 out of 7 studies) and terminal stance (1 out of 7 studies), and lower knee flexor moment at midstance (1 out of 7 studies). When comparing the two knees of the ACLD group, one study investigated the internal-external rotation kneemoment with no significant difference. Conclusion(s):There is limited and inconsistent evidence of altered knee kinematic and kinetic in the in individualswith chronicACLD;. Themost consistentfindingwas greater knee flexion during the stance phase. Implications: There is a need for more prospective studies that evaluate the gait characteristics of the chronic ACLD knee population in all planes; especially in the frontal and transverse. If consistently occurring gait deviations can be identified, it will provide insight in the initiation of knee osteoarthritis in individuals with chronic ACLD.

Anatomic anterior cruciate ligament reconstruction: reducing anterior tibial subluxation.

To measure and compare the amount of anterior tibial subluxation (ATS) after anatomic ACL reconstruction for both acute and chronic ACL-deficient patients. Fifty-two patients were clinically and radiographically evaluated after primary, unilateral, anatomic ACL reconstruction. Post-operative true lateral radiographs were obtained of both knees with the patient in supine position and knees in full passive extension with heels on a standardized bolster. ATS was measured on the radiographs by two independent and blinded observers. ATS was calculated as the side-to-side difference in tibial position relative to the femur. An independent t test was used to compare ATS between those undergoing anatomic reconstruction for an acute versus chronic ACL injury. Chronic ACL deficiency was defined as more than 12weeks from injury to surgery. Patients averaged 26.4±11.5years (mean±SD) of age, 43.6% were female, and 48.1% suffered an injury of the left knee. There were 30 and 22 patients in the acute and chronic groups, respectively. The median duration from injury to reconstruction for the acute group was 5 versus 31weeks for the chronic group. After anatomic ACL reconstruction, the mean ATS was 1.0±2.1mm. There was no statistical difference in ATS between the acute and chronic groups (1.2±2.0 vs. 0.6±2.3mm, n.s.). Assessment of inter-tester reliability for radiographic evaluation of ATS revealed an excellent intraclass correlation coefficient of 0.894. Anatomic ACL reconstruction reduces ATS with a mean difference of 1.0mm from the healthy contralateral limb. This study did not find a statistical difference in ATS between patients after anatomic ACL reconstruction in the acute or chronic phase. These observations suggest that anatomic ACL reconstruction, performed in either the acute or the chronic phase, approaches the normal AP relationship of the tibiofemoral joint. IV.

Increased meniscal loading after anterior cruciate ligament transection in vivo: a longitudinal study in sheep.

Meniscal injury has been well documented as a frequent consequence of both acute and chronic ACL deficiency. The purpose of this study was to evaluate the effect of ACL deficiency on meniscal loads in vivo and determine how these loads would change over time after ACL injury. The in vivo kinematics of the stifle joint of five sheep were measured during normal gait, as well as 4 and 20 weeks after ACL transection. A unique robotic testing platform was then programmed to reproduce all the previously recorded kinematics and the loads carried by medial and lateral menisci during gait were estimated. The results demonstrated a significant increase in both medial and lateral meniscal loads 20 weeks following ACL transection, mainly during mid-stance phase of gait (p = 0.007 and p = 0.003, respectively), with interesting inter-subject variability. A moderate correlation (R(2) ≥ 0.5) between in situ meniscal loads and anterior tibial translations was also detected over time after injury, increased translations post injury generally corresponded to larger meniscal loads. The dramatic increase in meniscal loads long term post ACL transection probably explains the meniscal changes or injuries reported clinically in many chronic ACL-deficient knees.

A novel clinical approach for assessing hop landing strategies: a 2D telescopic inverted pendulum (TIP) model.

Single leg hop for distance is used to inform rehabilitation and return to sport following anterior cruciate ligament reconstruction. However, impairment of landing mechanics may persist after the recommended performance parameter (hop distance) has been met; therefore, alternative methods are required. This study follows the COSMIN guideline to investigate the measurement properties of data from a new instrument (2D TIP). This is a simple motion analysis instrument to assess landing strategy based on more complex biomechanical modelling. Data collected in the clinical setting from 30 subjects with chronic ACL deficiency (mean 15.5, SD 4.3 months following injury) before and 6 months after ACL reconstruction and a healthy control group were analysed. Reliability and measurement error were calculated using two repeated measures from three independent raters. Construct validity was assessed by hypothesis testing, and known groups validity and responsiveness were defined by differences between groups. The data demonstrate excellent inter-rater (ICC = 0.81-1.00) and intra-rater (ICC = 0.85-1.00) reliability with low measurement error. Of the eight construct validity hypothesis, six were fully and two partially supported. Between-group differences were significant (P < 0.05) supporting the validity and responsiveness hypothesis. 2D TIP is a simple and inexpensive instrument for assessing landing strategy that has demonstrated appropriate reliability, validity and responsiveness in the ACL-injured population. The instrument will now be used to identify altered movement strategies and develop novel rehabilitation interventions that target strategy and performance. Prospective diagnostic study, Level II.

Anterior knee laxity measurement using stress radiographs and the GNRB® system versus intraoperative navigation

Anterior knee laxity measurement serves both to diagnose and to evaluate the severity of anterior cruciate ligament (ACL) damage. We tested the hypothesis that anterior laxity measurements of ACL-deficient knees obtained using the GNRB(®) system and stress radiographs differed from each other and from intraoperative navigation measurement taken as the reference standard. Twenty-one patients with chronic ACL deficiency underwent arthroscopic ACL reconstruction. Anterior knee laxity was measured preoperatively using the GNRB(®) system without anaesthesia and anterior-drawer stress radiographs under anaesthesia then intraoperatively using a non-image-based navigation system. The three measurements differed significantly (P=0.05). A systematic measurement error of -3.7 mm occurred for both preoperative measurements versus the reference standard. No significant difference was found between the two preoperative measurements. The GNRB(®) system should be preferred over stress radiographs, as reliability is similar but no radiation exposure is required. Both preoperative measurement methods underestimate anterior laxity as measured intraoperatively using the navigation system. This systematic bias may be relevant to treatment decision-making. II, development of a diagnostic criterion in consecutive patients versus a validated reference standard.

BIOMECHANICAL ANALYSIS OF THE ANTERIOR CRUCIATE LIGAMENT DEFICIENCY IN THE TRANSVERSE PLANE. A LABORATORY IN VIVO CONTROLLED STUDY

Centre for Sports and Exercise Medicine, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, UKBackgroundRotational instability due to anterior cruciate ligament (ACL) deficiency or...

ACL reconstruction with physiological graft tension by intraoperative adjustment of the anteroposterior translation to the uninjured contralateral knee

Fixation of anterior cruciate ligament (ACL) substitutes with non-physiological anteroposterior translation (APT) worsens outcome. The aim was to present a technique for physiological APT adjustment of the transplant in ACL reconstruction and its outcome at midterm. In a consecutive series of 28 patients (age 32 ± 11 years, 24 male), chronic ACL deficiency was treated by bone-patella-tendon-bone reconstruction. Transplant APT was adjusted to that of the contralateral uninjured ACL, measured 3, 6, and 12 months postoperatively using the Rolimeter. At a median follow-up of 5.3 years (3-8 years), 82% of the patients were re-evaluated with APT measurement and using IKDC-, Tegner-, Lysholm-Scores, conventional radiographs and MRI. No differences in APT (mean ± SD) between uninjured and reconstructed knees were observed after adjustment (6 ± 1 versus 6 ± 1 mm, n.s.). Three months postoperatively, a statistically significant increase in APT (7 ± 1 mm) and a further increase at midterm (9 ± 2 mm) were observed. Patients scored "normal" or "nearly normal", respectively, in 79% (IKDC) and 4 (3-9) points (Tegner; median, range) or 89 ± 9 points (Lysholm; mean ± SD). Radiological evaluation showed no, minimal or moderate joint degeneration in 5, 20 and 75% of patients, respectively. MRI confirmed intact ACL transplants in all patients. ACL reconstruction using the presented technique was considered successful, as patients did not suffer from subjective instability, radiographic analysis did not provide evidence for graft rupture at midterm. However, APT increase and occurrence of degenerative changes in reconstructed knees at the midterm might not be prevented even by restoration of a physiological APT in ACL reconstruction. The Rolimeter can be used for quick and easy intraoperative indirect control of the applied tension to the ACL transplant by measuring the APT to obtain physiological tensioning resulting in a satisfying outcome at midterm. IV.

Combined ACL reconstruction and closing-wedge HTO for varus angulated ACL-deficient knees

To report the medium-term clinical and radiographic outcomes of a group of patients who underwent anterior cruciate ligament (ACL) surgery combined with high tibial osteotomy (HTO) for varus-related early medial osteoarthritis (OA) and ACL deficiency knee. Thirty-two patients underwent single-bundle over-the-top ACL reconstruction or revision surgery and a concomitant closing-wedge lateral HTO. The mean age at surgery was 40.1 ± 8.1 years. Evaluation at a mean of 6.5 ± 2.7 years of follow-up consisted of subjective and objective IKDC, Tegner Activity Level, EQ-5D, VAS for pain and AP laxity assessment with KT-1000 arthrometer. Limb alignment and OA changes were evaluated on radiographs. All scores significantly improved from pre-operative status to final follow-up. KT-1000 evaluation showed a mean side-to-side difference of 2.2 ± 1.0 mm. Two patients were considered as failures. The mean correction of the limb alignment was 5.6° ± 2.8°. Posterior tibial slope decreased at a mean of 1.2° ± 0.9°. At final follow-up, the mechanical axes crossed the medial-lateral length of tibial plateau at a mean of 56 ± 23 %, with only 1 patient (3 %) presenting severe varus alignment. OA progression was recorded only on the medial compartment (p = 0.0230), with severe medial OA in 22 % of the patients. No patients underwent osteotomy revision, ACL revision, UKA or TKA. The described technique allowed patients with medial OA, varus alignment and chronic ACL deficiency to restore knee laxity, correct alignment and resume a recreational level of activity at 6.5 years of follow-up.

Articular and Meniscal Pathology Associated with Primary Anterior Cruciate Ligament Reconstruction

The abnormal kinematics, contact pressures, and repeated episodes of instability observed in chronic anterior cruciate ligament (ACL) deficiency suggest that these patients may be predisposed to early degenerative changes and associated pathologies such as meniscal tears and chondral injury. Injury to the cartilage and associated structures at the time of ACL rupture, in combination with the inflammatory mediators released at the time of injury, may create irreversible damage to the knee despite restoration of normal knee kinematics with an ACL reconstruction. Patients undergoing acute ACL reconstruction have a higher incidence of lateral meniscal tears and less severe chondral changes when compared with patients undergoing late ACL reconstruction. Older patients likely have a higher incidence of chondral and meniscal pathology compared with younger patients. A retrospective chart review of a single surgeon's ACL practice over 20 years was performed. A surgical data packet was used to record patient demographics, location, grade, and number of chondral injuries as well as location and pattern of meniscal injuries at the time of ACL reconstruction. Patients (N = 709) were divided into three subgroups according to their time from injury to surgery; acute (less than 4 weeks, N = 121), subacute (4 to 8 weeks, N = 146), and chronic (8 weeks or more, N = 442). Older patients had a higher incidence of more severe chondral grade and number of chondral injuries at the time of ACL reconstruction. Patients undergoing surgery more than 8 weeks after injury had a statistically significant more severe chondral grade in the medial compartment when compared with those that had surgery less than 8 weeks after injury. A similar observation was not found in the lateral compartment. With regard to meniscal pathology, full-thickness medial meniscal tears were likely to be bucket-type tears regardless of the chronicity of the injury. Similarly, full-thickness lateral meniscal tears were more often flap-type tears independent of the time interval between injury and surgery. Partial-thickness tears were common both medially and laterally. Patient's age and chronicity of ACL tear greater than 8 weeks are both significant factors in medial compartment chondral pathology. Patients with delayed reconstruction may have greater associated pathology.

Impact of Partial and complete rupture of anterior cruciate ligament on medial meniscus: A cadavaric study.

Background:The clinical relationship between medial meniscus tear and anterior cruciate ligament (ACL) rupture has been well documented. However, the mechanism of this clinical phenomenon is not exactly explained. Our aim is to investigate the biomechanical impact of partial and complete ACL rupture on different parts of medial meniscus.Materials and Methods:Twelve fresh human cadaveric knee specimens were divided into four groups: ACL intact (ACL-I), anteromedial bundle transection (AMB-T), posterolateral bundle transection (PLB-T), and ACL complete transection (ACL-T) group. Strain on the anterior horn, body part, and posterior horn of medial meniscus were measured under 200 N axial compressive tibial load at 0°, 30°, 60°, and 90° of knee flexion, respectively.Results:Compared with the control group (ACL-I), the ACL-T group had a higher strain on whole medial meniscus at 0°, 60°, and 90° of flexion. But at 30°, it had a higher strain on posterior horn of meniscus only. As to PLB-T group, strain on whole meniscus increased at full extension, while strain increased on posterior horn at 30° and on body of meniscus at 60°. However, AMB-T only brought about higher strain at 60° of flexion on body and posterior horn of meniscus.Conclusions:Similar to complete rupture, partial rupture of ACL can also trigger strain concentration on medial meniscus, especially posterior horn, which may be a more critical reason for meniscus injury associated with chronic ACL deficiency.