Intact Anterior Cruciate Ligament Research Articles

Similar Outcomes After Osteochondral Allograft Transplantation in Anterior Cruciate Ligament-Intact and -Reconstructed Knees: A Comparative Matched-Group Analysis With Minimum 2-Year Follow-Up

To compare failure rates and clinical outcomes of osteochondral allograft transplantation (OCA) in anterior cruciate ligament (ACL)-intact versus ACL-reconstructed knees at midterm follow-up. After a priori power analysis, a prospective registry of patients treated with OCA for focal chondral lesions ≥2cm2 in size with minimum 2-year follow-up was used to match ACL-reconstructed knees with ACL-intact knees by age, sex, and primary chondral defect location. Exclusion criteria included meniscus transplantation, realignment osteotomy, or other ligamentous injury. Complications, reoperations, and patient responses to validated outcome measures were reviewed. Failure was defined by any procedure involving allograft removal/revision or conversion to arthroplasty. Kaplan-Meier analysis and multivariate Cox regression were performed to evaluate the association of ACL reconstruction (ACLR) with failure. A total of 50 ACL-intact and 25 ACL-reconstructed (18 prior, 7 concomitant) OCA patients were analyzed. The mean age was 36.2years (range, 14-62years). Mean follow-up was 3.9years (range, 2-14years). Patient demographics and chondral lesion characteristics were similar between groups. ACL-reconstructed patients averaged 2.2 ± 1.9 prior surgeries on the ipsilateral knee compared with 1.4 ± 1.4 surgeries for ACL-intact patients (P= .014). Grafts used for the last ACLR included bone-patellar tendon-bone autograft, hamstring autograft, Achilles tendon allograft, and tibialis allograft (data available for only 11 of 25 patients). At final follow-up, 22% of ACL-intact and 32% of ACL-reconstructed patients had undergone reoperation. OCA survivorship was 90% and 96% at 2years and 79% and 85% at 5years in ACL-intact and ACL-reconstructed patients, respectively (P= .774). ACLR was not independently associated with failure. Both groups demonstrated clinically significant improvements in the Short Form-36 pain and physical functioning, International Knee Documentation Committee subjective, and Knee Outcome Survey-Activities of Daily Living scores at final follow-up (P<.001), with no significant differences in preoperative, postoperative, and change scores between groups. OCA in the setting of prior or concomitant ACLR does not portend higher failure rates or compromise clinical outcomes. Level III, retrospective comparative study.

Anatomic and non-anatomic anterior cruciate ligament posterolateral bundle augmentation affects graft function.

The purpose of this study is to compare knee laxity and graft function (tissue force) between anatomic and non-anatomic posterolateral (PL) bundle augmentation. Twelve (n=12) fresh-frozen mature, unpaired porcine knees were tested using a robotic testing system. Four knee states were compared: (a) intact anterior cruciate ligament (ACL), (b) deficient PL and intermediate bundles, (c) anatomic PL augmentation, and (d) non-anatomic PL augmentation. Anterior tibial translation (ATT), internal rotation (IR) and external rotation (ER), and the in situ tissue force were measured under an 89.0-N anterior tibial load and 4.0-Nm internal and external tibial torques. Both anatomic and non-anatomic PL augmentation restored the ER, IR, and ATT of the intact knee at all knee flexion angles (n.s.). Both anatomic and non-anatomic PL augmentation restored the in situ tissue force of the ACL during ER and IR loading and ATT loading at all knee flexion angles except at 60° of knee flexion, where the non-anatomic PL augmentation did not restore the in situ tissue force of the ACL during external rotation loading and the anatomic PL augmentation did not restore the in situ tissue force of the ACL during IR loading. Furthermore, there were no differences in ATT, IR, ER, and in situ tissue force under anterior tibial loading, IR and ER loading between the two reconstruction groups. There were no significant differences between anatomic and non-anatomic PL augmentation using the porcine knee model.

Biomechanical Evaluation of Pediatric Anterior Cruciate Ligament Reconstruction Techniques with and without the Anterolateral Ligament

Objectives:Management of anterior cruciate ligament (ACL) injuries in skeletally immature patients is controversial and several surgical procedures have been developed. The two most popular physeal sparing procedures are the iliotibial band (ITB) ACL reconstruction (ACLR) and the all-epiphyseal (AE) ACLR. There has been some concern for over-constraint of the knee with the ITB ACLR while the AE ACLR is technically challenging and can still risk growth disturbance. There has been interest recently into the anterolateral ligament (ALL) and its role in rotational stability, but it has not been assessed in the setting of pediatric ACLR techniques. The ITB ACLR includes a lateral tenodesis of the IT band to the femur that closely approximates the ALL. Our hypothesis is that the ITB ACLR and AE ACLR with ALL reconstruction (ALLR) will best replicate the biomechanics profile of the intact ACL.Methods:Eight cadaveric legs were statically loaded with an anterior drawer force and varus, valgus, internal and external rotational moments at 0°, 30°, 60°, and 90° of flexion. Displacement and rotation was recorded in the following conditions: intact ACL/intact ALL, ACL deficient/intact ALL, ITB ACLR/intact ALL, ITB ACLR/ALL deficient, ACL deficient/ALL deficient, AE ACLR/ALL deficient, AE ACLR/ALLR.Results:Both ACLR techniques reduced anterior translation from the ACL deficient state but neither restored translation to the intact state (p<0.05) except in full extension. ALL deficiency increased anterior translation in the ACL deficient state (p<0.05). In rotational testing, only the ACL deficient/ALL deficient state had a significant increase in internal rotation (p<0.05). This was significantly restored at all flexion angles with the ITB ACLR. There was no rotational over-constraint in any flexion angle with the ITB ACLR. The AE ACLR/ALL deficient state and AE ACLR/ALLR improved rotational stability at lower flexion angles, but not at 60° and 90°. There were no significant changes in varus/valgus moments.Conclusion:In this model, the ITB ACLR best corrected both parameters at all angles without over-constraining the knee and without the need for an ALLR. The AE ACLR and AE ACLR/ALLR improved both parameters but not at all flexion angles. The ITB ACLR appears to be the simpler pediatric ACLR technique to regain translational and rotational stability. ALL deficiency in the knee increased anterior displacement and rotational moments in the ACL deficient state.

Anterior cruciate ligament tibial insertion site is elliptical or triangular shaped in healthy young adults: high-resolution 3-T MRI analysis.

To clarify the morphology of anterior cruciate ligament (ACL) tibial insertion site in healthy young knees using high-resolution 3-T MRI. Subjects were 50 ACL-reconstructed patients with a mean age of 21.4±6.8years. The contralateral healthy knees were scanned using high-resolution 3-T MRI. The tibial insertion sites of the anteromedial (AM) and posterolateral (PL) bundle fibres, and the ACL attachment on the anterior horn of lateral meniscus (AHLM) were segmented from the MR images, and 3D models were reconstructed to evaluate the morphology. The shape of ACL footprint was qualitatively analysed, and the size of AM and PL attachments and AHLM overlapped area was measured digitally. Tibial AM and PL bundles were clearly identified in 42 of 50 knees (84.0%). Morphology of the whole ACL tibial insertion site was elliptical in 23 knees (54.8%) and triangular in 19 knees (45.2%), but not classified as C-shape in any knees. However, the AM bundle attachment was of C-shape in 29 knees (69.0%) and band-like in 13 knees (31.0%). Overlap of ACL on AHLM was found in 26 knees (61.9%), and the size of the overlapped area was 4.8±4.7% of the whole ACL insertion site. 3D morphology of the intact ACL tibial insertion site analysed by high-resolution 3-T MRI was elliptical or triangular in healthy young knees. However, the AM bundle insertion site was of C-shape or band-like. A small lateral portion of the ACL was overlapped with the AHLM. As for clinical relevance, these findings should be considered in order to reproduce the native ACL insertion site sufficiently. III.

ACL graft metabolic activity assessed by 18FDG PET–MRI

BackgroundTo demonstrate the use of 18Fluorodeoxyglucose positron emission tomography (PET) and magnetic resonance imaging (MRI) in combination (18FDG-PET) to assess the metabolic activity of ACL graft tissue and evaluate the utility of this technique for ligament imaging. MethodsTwenty-one knees with intact ACL grafts in 19 patients at multiple time points following ACL reconstruction were recruited to participate. PET–MRI imaging was performed using a custom device to place knees in the same position for both studies. Images were co-registered for quantification of 18FDG-PET standardized uptake value (SUV) for the proximal, middle, and distal ACL was quantified. Signal in extra-articular muscle tissue in the index knee was also recorded as a control. Signal from each location was compared based on how far post-operative each knee was from ACL reconstruction (<6months, six to 12months, 12–24months, or >24months). ResultsSignificant differences in 18FDG PET SUV between the four time points were observed in the proximal (p=0.02), middle (p=0.004), and distal (p=0.007) portions of the ACL graft. The greater than 24months group was noted to be different from other groups in each case. No difference in PET 18FDG SUV was noted in the extra-articular muscle in the index knee in each time group (p=0.61). ConclusionsMetabolic activity was noted to be significantly lower in grafts imaged greater than two years post-reconstruction relative to those grafts that had been in place for shorter periods of time.

The angle of inclination of the native ACL in the coronal and sagittal planes.

The purpose of this cross-sectional study was to evaluate the angle of inclination of the native anterior cruciate ligament (ACL) in both the sagittal and coronal planes and to evaluate these findings based on sex, height, BMI, and skeletal maturity. Inclusion criteria for the study included patients undergoing routine magnetic resonance imaging (MRI) of the knee at a single outpatient orthopedic center who had an intact ACL on MRI. Measurements of the angle of inclination were made on MRIs in both the sagittal and coronal planes. Patients were compared based on sex, height, BMI, and skeletal maturity. One-hundred and eighty-eight patients were included (36 skeletally immature/152 skeletally mature; 98 male/90 female). The overall angle of inclination was 74.3° ± 4.8° in the coronal plane and 46.9° ± 4.9° in the sagittal plane. Skeletally immature patients (coronal: 71.8°±6.1°; sagittal: 44.7°±5.5°) were significantly different in both coronal and sagittal planes (P = 0.04 and 0.01, respectively) from skeletally mature patients (coronal: 75.3°±4.7°; sagittal: 47.4°±4.7°). There were no differences based on sex, height, or BMI. There are differences between the angle of inclination findings in this study and other studies, which could be due to MRI and measurement techniques. Clinically, skeletal maturity may be important to account for when using the ACL angle of inclination to evaluate anatomic ACL reconstruction. Prognostic retrospective study, Level of evidence III.

Passive Anterior Tibial Subluxation in the Setting of Anterior Cruciate Ligament Injuries: A Comparative Analysis of Ligament-Deficient States

Background: Static anterior tibial subluxation after an anterior cruciate ligament (ACL) injury highlights the abnormal relationship between the tibia and femur in patients with ACL insufficiency, although causal factors including injuries to secondary stabilizers or the time from injury to reconstruction have not been examined. Purpose: To determine static relationships between the tibia and femur in patients with various states of ACL deficiency and to identify factors associated with anterior tibial subluxation. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Patients treated for ACL injuries were identified from an institutional registry and assigned to 1 of 4 cohorts: intact ACL, acute ACL disruption, chronic ACL disruption, and failed ACL reconstruction (ACLR). Anterior tibial subluxation of the medial and lateral compartments relative to the femoral condyles were measured on magnetic resonance imaging (MRI), and an MRI evaluation for meniscal tears, chondral defects, and injuries to the anterolateral ligament (ALL) was performed. Results: One hundred eighty-six ACL-insufficient knees met inclusion criteria, with 26 patients without an ACL injury utilized as a control group. In the lateral compartment, the mean anterior tibial subluxation measured 0.78 mm for the control group (n = 26), 2.81 mm for the acute ACL injury group (n = 74), 3.64 mm for the chronic ACL injury group (n = 40), and 4.91 mm for the failed ACLR group (n = 72). In the failed ACLR group, 37.5% of patients demonstrated lateral compartment anterior subluxation ≥6 mm, and 11.1% of this group had anterior subluxation of the lateral compartment ≥10 mm. Multivariate regression revealed that the presence of both medial and lateral chondral defects was associated with a mean 1.09-mm increase in subluxation of the medial compartment (P = .013). The combination of medial and lateral meniscal tears was an independent predictor of increased lateral tibia subluxation by 1.611 mm (P = .0022). Additionally, across all knee states, an injury to the ALL was associated with increased anterior tibial subluxation in both the medial compartment (P = .0438) and lateral compartment (P = .0046). In 29.4% of knees with ALL injuries, lateral tibial subluxation was ≥6 mm, but with multivariate regression analysis, an ALL injury was not an independent predictor of anterior subluxation of the lateral compartment. Conclusion: Knees with failed ACLR are associated with more anterior tibial subluxation than those with primary ACL deficiency. Using previously reported thresholds of 6 to 10 mm of lateral compartment subluxation for a positive pivot shift, between 11.1% and 37.5% of knees with failed ACLR may be in a “resting pivoted position.” In primary ACL-deficient knees, anterior tibial subluxation is associated with chondral injuries and meniscal tears but not injury chronicity.

Validity of rotational laxity coupled with anterior translation of the knee: A cadaveric study comparing radiostereometry and the Rotab®

BackgroundIn current practice, anterior cruciate ligament (ACL) tears can be diagnosed using several devices to measure anterior tibial translation and rotational knee laxity, but these measures are never collected together. The Rotab®, which yields simultaneous measurements of anterior tibial translation and passive lower limb rotation under stress, would therefore be advantageous in current practice, but its reliability has never been tested. Aim of studyTo evaluate the accuracy and reliability of the Rotab® compared to the reference system, radiostereometric analysis (RSA). MethodsThis anatomical study was conducted on 14 lower limbs collected from fresh cadavers. Simultaneous measurements of anterior tibial translation and rotation were obtained with both systems, with antero-posterior (AP) forces of 134N and 250N using the Rotab®. Measurements were made on intact ACL and then repeated after ACL section. Variables were analyzed in univariate analysis by ANOVA, and the intraclass correlation coefficient (ICC) between the systems was determined by the Bland and Altman method. ResultsThe difference between the two methods for evaluating anterior tibial translation was 0.05±0.98mm at 134N and 0.29±1.04mm at 250N. The correlation between the tests was high (r134=r250=0.97, p=0.8). The difference between the two methods for rotational laxity was 0.69±2.7° at 134N and 0.5±0.6° at 250N. The Rotab® showed a significant difference only at 250N for rotational laxity after the ACL tear. ConclusionThe Rotab® is a reliable device to measure rotational laxity coupled with anterior translation of the knee.

Anterolateral Ligament and Iliotibial Band Control of Rotational Stability in the Anterior Cruciate Ligament–Intact Knee: Defined by Tibiofemoral Compartment Translations and Rotations

To determine the stabilizing effect of the anterolateral ligament (ALL) and iliotibial band (ITB) in resisting internal tibial rotation limits and anterior subluxations of the tibiofemoral compartments in anterior cruciate ligament (ACL)-intact knees during anterior drawer, internal rotation, and under 2 different 4-degree-of-freedom pivot-shift conditions. A 6-degree-of-freedom robotic simulator tested 19 fresh-frozen cadaver specimens with 3 testing conditions: intact, ALL- or ITB-sectioned (random), and both ALL and ITB sectioned. Anterior translation of the medial and lateral compartments and internal tibial rotation were measured under 100N anterior drawer, 5 Nm internal rotation, and 2 pivot-shift conditions. Statistical equivalence was defined as P < .05. Sectioning the ALL alone had no effect on lateral compartment translation or internal rotation under any loading condition (equivalent P < .05). After ITB sectioning alone, small increases in internal rotation were found under 5 Nm internal rotation at 60° (3.0° [90% confidence interval 1.9-4.1]; P= .99) and 90° (2.2° [90% confidence interval 1.5-2.9]; P= .84) flexion. After both ALL and ITB were sectioned, increases in internal rotation of 1.7°, 4.5°, and 3.9° occurred at 25°, 60°, and 90° flexion, respectively (P > .05). Small increases in pivot-shift internal rotation (Group 1: 2.0° [90% confidence interval 1.4-2.6]; P= .52) and lateral compartment translation occurred (Group 1: 0.9mm [90% confidence interval 0.7-1.1]; P < .001). Sectioning the ALL does not lead to an increase in tibiofemoral compartment subluxations in the pivot-shift test with an intact ACL. Accordingly the ALL would not represent a primary restraint to pivot-shift subluxations. ALL sectioning alone does not lead to an increase in internal rotation motion limits, however sectioning both the ALL and ITB did produce small increases in rotation limits at higher flexion angles which would likely not be clinically detectable. A deficiency to both the ALL and ITB during invitro-simulated pivot-shift tests and internal rotation tests results in small, clinically undetectable changes in knee kinematics in the majority of knees assuming intact ACL function.

The effect of anterior cruciate ligament graft rotation on knee biomechanics.

The purpose of this study was to evaluate the effects on knee biomechanics of rotating the distal end of the bone-patellar tendon graft 90° in anatomic single-bundle (SB) anterior cruciate ligament (ACL) reconstruction with a porcine model. Twenty (n=20) porcine knees were evaluated using a robotic testing system. Two groups and three knee states were compared: (1) intact ACL, (2) deficient ACL and (3) anatomic SB ACL reconstruction with (a) non-rotated graft or (b) rotated graft (anatomic external fibre rotation). Anterior tibial translation (ATT), internal (IR) and external rotation (ER) and the in situ tissue force were measured under an 89-N anterior tibial (AT) load and 4-Nm internal and external tibial torques. A significant difference from the intact ACL was found in ATT at 60° and 90° of knee flexion for rotated and non-rotated graft reconstructions (p<0.05). There was a significant difference in the in situ force from the intact ACL with AT loading for rotated and non-rotated graft reconstructions at 60° and 90° of knee flexion (p<0.05). Under IR loading, the in situ force was significantly different from the intact ACL at 30° and 60° of knee flexion for rotated and non-rotated graft reconstructions (p<0.05). There were no significant differences in ATT, IR, ER and the in situ force between rotated and non-rotated reconstructions. Graft rotation can be used with anatomic SB ACL reconstruction and not have a deleterious effect on knee anterior and rotational biomechanics. This study has clinical relevance in regard to the use of graft rotation to better reproduce the native ACL fibre orientation in ACL reconstruction.

Intégration dans le tunnel fémoral du greffon dans les reconstructions du LCA : voie transportale versus technique outside-in

Purpose Although the independent drilling techniques using transportal portal or outside-in approaches in ACL reconstruction have some advantages over the trans-tibial technique in placing the anatomical femoral tunnel, these techniques may make an acute graft-bending angle at the femoral tunnel entry or result in a short femoral tunnel length. However, there have been no reports on whether an acute graft-bending angle of an independent drilling technique might result in poor graft healing or negatively affecting clinical outcomes. The purpose of this study was to compare femoral tunnel geometry including tunnel position, length, and graft bending angle between the transportal and the outside-in techniques in ACL reconstruction and discover whether such differences in tunnel geometry could influence graft healing or clinical outcomes. Methods Sixty patients with anatomical single-bundle ACL reconstruction performed with use of either the transportal technique (32 patients) or the outside-in technique (28 patients) were included for this study. The femoral tunnel location, length and graft-bending angle at the femoral tunnel were analyzed on the 3D CT knee model, and we compared the location and length of the femoral tunnel, and graft-bending angle between the two techniques. Each group underwent MRI scans at least 1 year (range of 1–2 years) following the ACL reconstruction. We confirmed that all patients showed an intact ACL graft on the MRI images. On the oblique axial image taken after the ACL reconstruction, to determine graft healing at the femoral and tibial tunnels, and the intra-articular portion, the graft signal intensity ratio was calculated by dividing signal intensity (SI) of the reconstructed ACL by that of the posterior cruciate ligament (PCL) in the region-of-interest (ROI). We also compared the clinical outcomes in terms of Tegner activity scores, the International Knee Documentation Committee (IKDC) scores and Lachman and pivot-shift test results. Results While the location of femoral tunnel was similar in both groups, the femoral tunnel length was a little bit longer in the outside-in technique (37 vs. 32 mm, P = 0.07). Meanwhile, the outside-in technique showed a more significant acute graft tunnel angle than the transportal technique (100 vs. 113, P = 0.04). However, the signal intensity ratios of the grafts (compared with SI of PCL) were similar in femoral tunnel, tibial tunnel or intrarticular portions. Moreover, there were no significant statistical differences between the two groups in terms of IKDC scores (86.1 vs. 91.0, P = 0.32) and Tegner activity scores (6.5 vs. 6.8, P = 0.79). We also could not find any significant differences in the results of Lachman and pivot-shift tests. Conclusions Even though the outside-in technique in ACL reconstruction created a more acute femoral graft bending angle and a longer femoral tunnel length than the transportal technique, these had no negative effects in graft healing. In addition, the transportal and outside-in techniques in ACL reconstruction showed similar femoral tunnel positions, and no significant differences in clinical outcome. Therefore, the outside-in ACL reconstruction can be considered as the more effective method for surgeons to overcome the weakness of the traditional transportal technique.

Fracture de Segond

To measure the slope of the medial and lateral posterior horn of the meniscus and its contribution to the overall resulting posterior tibial slope (bone and meniscus combined slope) in anterior cruciate ligament–intact (ACLI) and –deficient (ACLD) knees.Magnetic resonance images of intact menisci in patients 16 to 60 years old were included. Posterior tibial bone slope (PTS) and meniscus slope (MS) were measured 25%, 50%, and 75% from the medial and lateral borders of the tibial plateau. Analysis of variance was used to determine differences in posterior tibial slopes between ACLD and ACLI knees and between sexes for ACLD and ACLI knees.192 ACLI patients (age 35.2 ± 9.6 years, mean ± standard deviation) and 159 ACLD patients (age 34.2 ± 10.3 years) were included. Medial and lateral PTS in ACLD was significantly (P = .00001) higher at 25%, 50%, and 75%. Medial and lateral MS in ACLD was significantly (P = .00001) lower at 25%, 50%, and 75%. There were no significant sex differences for medial or lateral MS in ACLD or ACLI patients (P = .51). The resultant combined medial and lateral slope in ACLD patients was significantly (P = .00001) lower at 25%, 50%, and 75%. There were no significant sex differences in PTS (P = .68), MS (P = .51), or resultant slope (P = .79)The results of this study strongly suggest that lower meniscal slopes of both the medial and lateral posterior horns are associated with ACL injuries in both males and females. Although the posterior horns reversed the bone PTS to an anterior inclined slope in both ACLD and ACLI patients, both the meniscus slope and the combined resultant slope were significantly lower and more positive at all 6 measured locations in ACLD knees.III, retrospective cohort study.

The results of Oxford unicompartmental knee arthroplasty in the United States: a mean ten-year survival analysis.

AimsApproved by the Food and Drug Administration in 2004, the Phase III Oxford Medial Partial Knee is used to treat anteromedial osteoarthritis (AMOA) in patients with an intact anterior cruciate ligament. This unicompartmental knee arthroplasty (UKA) is relatively new in the United States, and therefore long-term American results are lacking.Patients and MethodsThis is a single surgeon, retrospective study based on prospectively collected data, analysing a consecutive series of primary UKAs using the Phase III mobile-bearing Oxford Knee and Phase III instrumentation.Between July 2004 and December 2006, the senior author (RHE) carried out a medial UKA in 173 patients (213 knees) for anteromedial osteoarthritis or avascular necrosis (AVN). A total of 95 patients were men and 78 were women. Their mean age at surgery was 67 years (38 to 89) and mean body mass index 29.87 kg/m2 (17 to 62).The mean follow-up was ten years (4 to 11).ResultsSurvivorship of the Oxford UKA at ten years was 88%, using life table analysis. Implant survivorship at ten years was 95%. The most common cause for revision was the progression of osteoarthritis in the lateral compartment. The mean knee score element of the American Knee Society Score (AKSS) was 50 pre-operatively and increased to 93 post-operatively. The mean AKSS function score was 56 pre-operatively rising to 78 post-operativelyConclusionThis ten-year follow-up study of the Oxford UKA undertaken in the United States shows good survivorship and excellent function in a wide selection of patients with AMOA and AVN.Cite this article: Bone Joint J 2016;98-B(10 Suppl B):34–40.

Does location of patellofemoral chondral lesion influence outcome after Oxford medial compartmental knee arthroplasty?

AimsMedial unicompartmental knee arthroplasty (UKA) is associated with successful outcomes in carefully selected patient cohorts. We hypothesised that severity and location of patellofemoral cartilage lesions significantly influences functional outcome after Oxford medial compartmental knee arthroplasty.Patients and MethodsWe reviewed 100 consecutive UKAs at minimum eight-year follow-up (96 to 132). A single surgeon performed all procedures. Patients were selected based on clinical and plain radiographic assessment. All patients had end-stage medial compartment osteoarthritis (OA) with sparing of the lateral compartment and intact anterior cruciate ligaments. None of the patients had end-stage patellofemoral OA, but patients with anterior knee pain or partial thickness chondral loss were not excluded. There were 57 male and 43 female patients. The mean age at surgery was 69 years (41 to 82). At surgery the joint was carefully inspected for patellofemoral chondral loss and this was documented based on severity of cartilage loss (0 to 4 Outerbridge grading) and topographic location (medial, lateral, central, and superior or inferior). Functional scores collected included Oxford Knee Score (OKS), patient satisfaction scale and University College Hospital (UCH) knee score. Intraclass correlation was used to compare chondral damage to outcomes.ResultsAll patients documented significant improvement in pain and improved functional scores at mid-term follow-up. There were four revisions (mean 2.9 years, 2 to 4; standard deviation (sd) 0.9) in this cohort, three for tibial loosening and one for femoral loosening. There was one infection that was treated with debridement and insert exchange. The mean OKS improved from 23.2 (sd 7.1) to 39.1 (sd 6.9); p < 0.001. The cohort with central and lateral grade 3 patellofemoral OA documented lower mean satisfaction with pain (90, sd 11.8) and function (87.5, sd 10.3) on the patient satisfaction scale. On the UCH scale, patients reported significantly decreased mean overall scores (7.3, sd 1.2 vs 9, sd 2.3) as well as stair climb task (3.5, sd 0.3 vs 5, sd 0.1) when cartilage lesions were located centrally or laterally on the PFJ. Patients with medial chondral PFJ lesions behave similar to patients with no chondral lesions.ConclusionTopographical location and severity of cartilage damage of the patella can significantly influence function after successful Oxford medial UKA. Surgeons should factor this in when making their operative decision, and undertake to counsel patients appropriately.Cite this article: Bone Joint J 2016;98-B(10 Suppl B):11–15.

Using an accelerometer and the step-up-and-over test to evaluate the knee function of patients with anterior cruciate ligament reconstruction

BackgroundEvaluating the dynamic knee function of patients after anterior cruciate ligament reconstruction is a challenge. A variety of objective tests have been developed but for various reasons few are regularly used in the clinic. It may be practical to perform the step-up-and-over test with an accelerometer. MethodsA control group (N=26) and an experimental group with a reconstructed anterior cruciate ligament (N=25) completed questionnaires quantifying subjective knee function and fear of re-injury and then completed the step-up-and-over test. FindingsResults showed that the experimental group performed differently than the control group for the step-up-and-over test's Lift Symmetry and Impact Symmetry (P<0.05) and performance on these measures was related to the participant's subjective knee function (ρ=−0.46, P<0.01; ρ=−0.33, P<0.05, respectively). Supplemental results for individual leg performance and the patient's fear of re-injury are also reported and discussed. InterpretationPerformance on the step-up-and-over test is different for participants with anterior cruciate ligament reconstruction than for those with intact anterior cruciate ligaments, and that performance is related to one's opinion of their knee's function.

Anterior Cruciate Ligament Injuries Alter the Kinematics of Knees With or Without Meniscal Deficiency

Background: Numerous studies have investigated kinematic alterations in patients with an isolated anterior cruciate ligament (ACL) injury. However, a substantial proportion of patients with injured ACLs also have concomitant meniscal tears. Purpose: To evaluate the in vivo alteration of knee kinematics after an ACL tear, with or without a combined medial or lateral meniscal tear, during level walking activity. Study Design: Controlled laboratory study. Methods: Fifty-six patients with unilateral ACL-deficient (ACLD) knees were studied. Among these patients, 15 had isolated ACL injuries (group 1), 15 had combined ACL and medial meniscal injuries (group 2), 15 had combined ACL and lateral meniscal injuries (group 3), and 11 had combined ACL and medial/lateral meniscal injuries (group 4). The kinematics of each knee was determined using an optical tracking system during treadmill gait. Range of motion (ROM) and kinematic alterations were compared between the contralateral ACL-intact (ACLI) and ACLD knees. Results: All ACLD knees, with or without meniscal deficiency, had significantly less flexion than the ACLI knees (~3°-8°; P < .05). In groups 1, 3, and 4, the injured knees exhibited more femoral external rotation by approximately 1° to 2° (P < .05). Group 4 showed posterior femoral translation (anterior tibial translation) in the swing phase (~13 mm), while groups 2 and 3 showed increased anterior femoral translation (~2-3 mm). During medial-lateral translation, patients in group 2 had a more medial femoral shift (~4 mm) relative to the tibia initially, while those in group 4 exhibited a lateral femoral shift. Conclusion: The results indicate that meniscal injuries alter the kinematics of the ACLD knee when compared with knees with an isolated ACL injury. The location of the meniscal tear also affects knee kinematics. Clinical Relevance: Considering the varying effects of meniscal injuries on knee joint kinematics, these data provide insight into the pathological function of the ACL-injured knee joint during walking.

Effect of Changing the Joint Kinematics of Knees With a Ruptured Anterior Cruciate Ligament on the Molecular Biological Responses and Spontaneous Healing in a Rat Model

Background: The poor healing capacity of a completely ruptured anterior cruciate ligament (ACL) has been attributed to an insufficient vascular supply, cellular metabolism, and deficient premature scaffold formation because of the unique intra-articular environment. However, previous studies have focused on intra-articular factors without considering extra-articular factors, including the biomechanical aspects of ACL-deficient knees. Hypothesis: Changing the joint kinematics of an ACL-ruptured knee will improve cellular biological responses and lead to spontaneous healing through the mechanotransduction mechanism. Study Design: Controlled laboratory study. Methods: A total of 66 skeletally mature Wistar rats were randomly assigned to a sham-operated group (SO), ACL-transection group (ACL-T), controlled abnormal movement group (CAM), and an intact group (IN). The ACL was completely transected at the midportion in the ACL-T and CAM groups, and the CAM group underwent extra-articular braking to control for abnormal tibial translation. The SO group underwent skin and joint capsule incisions and tibial drilling, without ACL transection and extra-articular braking. The animals were allowed full cage activity until sacrifice at 1, 2, 4, 6, and 8 weeks postoperatively for histological, molecular biological, and biomechanical assessment. Results: All injured ACLs in the ACL-T group were not healed, but those in the CAM group healed spontaneously, showing a typical ligament healing response. Regarding the molecular biological response, there was an upregulation of anabolic factors (ie, transforming growth factor–β) and downregulation of catabolic factors (ie, matrix metalloproteinase). Examination of the mechanical properties at 8 weeks after injury showed that >50% of the strength of the intact ACL had returned. Conclusion: Our results suggest that changing the joint kinematics of knees with a ruptured ACL alters the molecular biological responses and leads to spontaneous healing. These data support our hypothesis that the mechanotransduction mechanism mediates molecular responses and determines whether the ACL will heal. Clinical Relevance: Elucidating the relationship between the mechanotransduction mechanism and healing responses in knees with completely ruptured ACLs may result in the development of novel nonsurgical treatment that enables the ACL to spontaneously heal in patients who are not suitable for reconstruction.

Kinematics of anterior cruciate ligament-deficient knees in a Chinese population during stair ascent.

BackgroundThe purpose of this study was to measure the tibiofemoral kinematics of anterior cruciate ligament (ACL) deficiency in a Chinese population and compare the kinematics with published data about a Caucasian population.MethodsUnilateral knees of 18 Chinese ACL-deficient (ACL-D) subjects were studied while subjects ascended stairs. Kinematic alteration was compared between ACL-D knees and contralateral ACL-intact (ACL-I) knees. The kinematic alteration of ACL deficiency was also compared between the Chinese population and published data about a Caucasian population.ResultsA statistical difference was found in the three-dimensional rotations between ACL-D and ACL-I knees. In the sagittal plane, ACL-I knees had a larger flexion angle than ACL-D knees during 40 to 50 % of the activity during stair ascent (P < 0.027) and throughout the gait cycle. A significant difference in rotational motion between ACL-D and ACL-I knees was also observed in the frontal plane during 40 to 60 % (P < 0.017) of the activity and in the transverse plane during 70 to 80 % (P < 0.028) of the activity. A greater tibial varus was demonstrated in the Chinese population while the published data revealed external tibial rotation and a statistical difference in translation in the Caucasian population.ConclusionsACL-D knees show different kinematics than ACL-I knees in the Chinese population. ACL-I knees had a larger flexion angle than ACL-D knees in the middle stage of the activity during stair ascent. A significant difference in rotational motion between ACL-D and ACL-I knees was also observed in the frontal plane during the middle phase and in the transverse plane during the terminal phase of the activity. A greater tibial varus was demonstrated in the Caucasian population while the published data revealed external tibial rotation and a statistical difference in translation in the Caucasian population.

COMBINED INSIDE-OUT AND ALL-INSIDE TECHNIQUE IN BUCKET-HANDLE MENISCUS TEARS.

ABSTRACTObjective: To determine the outcomes after combined inside-out and all-inside repair technique of bucket-handle meniscus tears. Methods: A retrospective review was made of patients with bucket-handle meniscus tears repaired with combined techniques, using the all-inside technique in posterior meniscal tears and the inside-out technique in the middle part of the meniscal tears. Meniscal healing was assessed clinically using Barrett's criteria and MRI. Results: The study comprised 52 patients with a mean age of 28.4 years old (range, 19-52 years old). The mean follow-up period was 31.3 months (range, 24-59 months). Two patients had ACL re-rupture, and complete meniscal healing was achieved in all but one patient. Although improved from preoperative status, Tegner and Lysholm scores were lower in the ACL reconstructed patients than in the intact ACL patients. Conclusion: Combined inside-out and all-inside meniscal repair technique is a successful and cost-effective treatment method in bucket-handle meniscus tears. Level of Evidence IV, Therapeutic Study.

Spontaneous Healing of the Ruptured Anterior Cruciate Ligament

Objectives:It is widely believed that ACL tears are incapable of healing. However, there are anecdotal experiences of the healed ACL and sporadic case reports and series documenting either clinical or radiographic evidence of healed ACL tears. A truly healed ACL would demonstrate a clinically stable knee on Lachman and pivot shift testing, normal return to function and MRI and/or arthroscopic documentation of a continuous ligament. This is in contrast to “copers” who have an ACL deficient knee but lack instability either because of good neuromuscular control or non-participation in activities which are heavily ACL dependent. In this prospective series we report on the presentation and 5 year follow-up of patients with both clinical and radiographically healed ACLs.Methods:19 patients who presented between July 2007 and April 2010 within 6 weeks of injury with clinical laxity and MRI confirmed ACL rupture. Patients subsequently demonstrated clinical knee stability at 8-12 weeks after pre-habilitation to obtain a pain free mobile joint. Prospective data was collected on these patients with MRI at 12 months, IKDC clinical and subjective scores, KT1000 instrumental laxity testing and Lysholm knee score at 12, 24 and 60 months.Results:At one year follow-up MRI 18/19 patients demonstrated a healed ACL with normal signal, normal trajectory and continuity of fibres. Remainder 1 patient demonstrated bridging of ACL tear with scar tissue and abnormal trajectory of fibers. 5 of 19 patients re-ruptured within 5 years of follow-up. At 5 years follow-up, intact healed ACL patients had a mean IKDC score of 88, mean Lysholm score of 92 and mean KT1000 score of 1.7 mm. 100% reported regular participation in strenuous sport.Conclusion:Although rare, spontaneous healing of the ACL is possible. The mechanism by which this occurs in unknown. It is recommended that reassessment of knee stability should be performed in the non-acute phase after an appropriate prehabilitation program prior to ACL reconstruction to ensure spontaneous healing of the ACL has not occurred.