Patellar dislocation is a common presentation with a clear management pathway. Sometimes, however, what a patient experiences as the patella dislocating may, in fact, be ACL insufficiency. We reviewed case notes and imaging of 315 consecutive ACL reconstructions, collecting data on the date and mechanism of injury, time to MRI, and reconstruction. We noted cases initially diagnosed as patellar dislocation. 25 of 315 (7.9%) patients were initially diagnosed with a patellar dislocation. Subsequently, however, MRI scans revealed no evidence of patellar dislocation and instead showed ACL rupture with pathognomonic pivot-shift bony oedema. The false patella dislocation group were 32% female and had an average age of 25; the rest of the group average age was 27.1 and there were a lower proportion of females; 21%. The false patella instability patients had a median waiting time of 412 days from injury to operation (range: 70-2445 days), compared to 392 days (range: 9 – 4212 days) for rest of the patients. 5 of the remaining 290 had MRIs showing patella oedema with medial patello-femoral ligament injury in addition to their ACL rupture. From our literature search this is a new finding which shows that ACL rupture can present with symptoms suggestive of patellar dislocation. These findings raise the risk that there are a group of people who have been diagnosed with patellar instability who instead have ACL insufficiency and so are at risk of meniscal and chondral damage. Further research should analyse those diagnosed with patellar instability to quantify missed ACL injuries

The Pivot-shift test is a clinical test for knee instability for patinets with Anterior cruciate ligament (ACL), however the test has low inter-observer reliability. Dynamic radiostereometry (dRSA) imaging is a highly precise method for objective evaluation of joint kinematics. The purpose of the study was to quantify precise knee kinematics during Pivot-shift test by use of the non-invasive dynamic RSA imaging. Eight human donor legs with hemipelvis were evaluated. Ligament lesion intervention of the ACL was performed during arthroscopy and anterolateral ligament (ALL) section was performed as a capsular incision. Pivot-shift test examination was recorded with dRSA on ligament intact knees, ACL-deficient knees and ACL+ALL-deficient knees. A Pivot-shift pattern was identifyable after ligament lesion as a change in tibial posterior drawer velocity from 7.8 mm/s in ligament intact knees, to 30.4 mm/s after ACL lesion, to 35.1 mm/s after combined ACL-ALL lesion. The anterior-posterior drawer excursion increased from 2.8 mm in ligament intact knees, to 7.2 mm after ACL lesion, to 7.6 mm after combined lesion. Furthermore a change in tibial rotation was found, with increasing external rotation at the end of the pivot-shift motion going from intact to ACL+ALL-deficient knees. This experimental study demonstrates the feasibility of RSA to objectively quantify the kinematic instability patterns of the knee during the Pivot-shift test. The dynamic parameters found through RSA displayed the kinematic changes from ACL to combined ACL-ALL ligament lesion

Aims

The aim of this prospective study was to assess the long-term clinical, radiological, functional, and quality of life (QoL)-related outcome of patients treated with the synthetic Ligament Advanced Reinforcement System (LARS) device for anterior cruciate ligament (ACL) rupture.

The primary purpose of this study was to assess whether patients presenting with clinical graft laxity following primary anatomic anterior cruciate ligament (ACL) reconstruction using hamstring autograft reported a significant difference in disease-specific quality-of-life (QOL) as measured by the ACL-QOL questionnaire. Clinical ACL graft laxity was assessed in a cohort of 1134/1436 (79%) of eligible patients using the Lachman and Pivot-shift tests pre-operatively and at 12- and 24-months following ACL reconstruction. Post-operative ACL laxity was assessed by an orthopaedic surgeon and a physical therapist who were blinded to each other's examination. If there was a discrepancy between the clinical examination findings from these two assessors, then a third impartial examiner assessed the patient to ensure a grading consensus was reached. Patients completed the ACL-QOL questionnaire pre-operatively, and 12- and 24-months post-operatively. Descriptive statistics were used to assess patient demographics, rate of post-operative ACL graft laxity, surgical failures, and ACL-QOL scores. A Spearman rho correlation coefficient was utilised to assess the relationships between ACL-QOL scores and the Lachman and Pivot-shift tests at 24-months post-operative. An independent t-test was used to determine if there were differences in the ACL-QOL scores of subjects who sustained a graft failure compared to the intact graft group. ACL-QOL scores and post-operative laxity were assessed using a one-way analysis of variance (ANOVA). There were 70 graft failures (6.17%) in the 1134 patients assessed at 24-months. A total of 226 patients (19.9%) demonstrated 24-months post-operative ACL graft laxity. An isolated positive Lachman test was assessed in 146 patients (12.9%), an isolated positive Pivot-shift test was apparent in 14 patients (1.2%), and combined positive Lachman and Pivot-shift tests were assessed in 66 patients (5.8%) at 24-months post-operative. There was a statistically significant relationship between 24-month post-operative graft laxity and ACL-QOL scores (p < 0.001). Specifically, there was a significant correlation between the ACL-QOL and the Lachman test (rho = −0.20, p < 0.001) as well as the Pivot-shift test (rho = −0.22, p < 0.001). There was no significant difference between the scores collected from the graft failure group prior to failure occurring (mean = 74.38, SD = 18.61), and the intact graft group (mean = 73.97, SD = 21.51). At 24-months post-operative, the one-way ANOVA demonstrated a statistically significant difference between the ACL-QOL scores of the no laxity group (mean = 79.1, SD = 16.9) and the combined positive Lachman and Pivot-shift group (mean = 68.5, SD = 22.9), (p = 0, mean difference = 10.6). Two-years post ACL reconstruction, 19.9% of patients presented with clinical graft laxity. Post-operative graft laxity was significantly correlated with lower ACL-QOL scores. The difference in ACL-QOL scores for patients with an isolated positive Lachman or Pivot-shift test did not meet the threshold of a clinically meaningful difference. Patients with clinical laxity on both the Lachman and Pivot-shift tests demonstrated the lowest patient-reported ACL-QOL scores, and these results exceeded the minimal clinically important difference

Previous studies have identified the anterolateral complex (ALC) as having an important role in controlling anterolateral rotatory laxity following anterior cruciate ligament injury and subsequent reconstruction. In particular, injury to the iliotibial band (ITB) and its component deep (dITB) and capsulo-osseous (coITB) layers, have been shown to significantly correlate with different grades of the pivot-shift test in patients with acute ACL injuries. However, the kinematic properties of the capsulo-osseous layer of the ITB, throughout knee range of motion, are not fully understood. The purpose of this study was to quantify the kinematic behaviour of the capsulo-osseous layer of the ITB through various degrees of knee flexion. Ten fresh-frozen cadaveric knee specimens were dissected to expose the capsulo-osseous layer of the iliotibial band. Radiopaque beads were embedded, at standardized increments (12.5%, 25%, 50% and 75% of total length from proximal to distal), into the tissue and fluoroscopic images were taken from 0o to 105o of knee flexion in 15° increments. The positions of the beads were identified in each image and the length, width, and area changes of the capsulo-osseous layer were calculated. Comparisons of the total length of the anterior and posterior borders of the coITB through knee ROM were conducted using a two-way (8 knee angles by 2 borders) repeated measures analysis of variance (rm-ANOVA), whereas the effect of knee angle on isometry and total area changes was assessed using one-way rm-ANOVAs (α=0.05). There was a significant increase in the length of the anterior capsulo-osseous layer at flexion angles greater than 15o and on the posterior border at angles greater than 75 o with changes occurring primarily at 12.5 % of the total length. In addition, at all flexion angles the length changes were significantly larger in the anterior border compared to the posterior border. Meanwhile, non-homogenous decreases in width and area were found with increasing flexion angle. The distance between the capsulo-osseous layer insertion on the distal femur and proximal tibia significantly increased from 60o-105o, maximal changes occurred at 105o (9.64 [4.12] %, p = 0.003). The primary finding of this study was that the coITB behaved in a non-isometric fashion, with significant increases in length occurring at flexion angles greater than 15o. Moreover, these changes in length were non-homogenous across the different regions of the coITB that were investigated, with the greatest changes occurring in the proximal segments (0–25%). The data presented here suggest that coITB in flexion angles from 0o to 105o behaves in a non-isometric fashion, with the majority of its length change occurring in its proximal segment. Further quantification of the pathway that the coITB takes with respect to osseous landmarks may result in improvements in ALC procedures as an augmentation to ACL reconstruction, thereby potentially improving rotational stability and clinical outcomes

The aim of an anterior cruciate ligament (ACL) reconstruction is to regain functional stability of the knee following ACL injury, ideally allowing patients to return to their pre-injury level of activity. The purpose of this study was to assess clinical, functional and patient-reported outcomes following primary ACL reconstruction with hamstring autograft. A prospective case-series design (n=1610) was used to gather data on post-operative ACL graft laxity, functional testing performance and scores on the ACL quality of life (ACL-QOL) questionnaire. Demographic data were collected for all patients. Post-operative ACL laxity assessment using the Lachman and Pivot-shift tests was completed independently on each patient by a physiotherapist and an orthopaedic surgeon at the 6-, 12- and 24-months post-operative appointments. A battery of functional tests was also assessed including single leg Bosu balance, and 4 single-leg hop tests. The hop tests provided a comparative assessment of limb-to-limb function. Patients completed the ACL-QOL at all time points. The degree and frequency of post-operative laxity was calculated. A Spearman's rank correlation matrix was undertaken to assess for relationships between post-operative laxity, functional test performance, and the ACL-QOL scores. A linear regression model was used to assess for relationships between the ACL-QOL scores, as well as the functional testing results, and patient demographic factors. ACLR patients were 55% male, with a mean age of 29.7 years (SD=10.4), mean BMI of 25 (SD=3.9), and mean Beighton score of 3.3 (SD=2.5). At clinical assessment 2-years post-operatively, 20.6% of patients demonstrated a positive Lachman test and 7.7% of patients demonstrated a positive Pivot-shift test. The mean ACL-QOL score was 28.6/100 (SD=13.4) pre-operatively, 58.2/100 (SD=17.6) at 6-months, 71.8/100 (SD=18.1) at 12-months, and 77.4/100 (SD=19.2) at 24-months post-operative. Functional tests assessing operative to non-operative limb performance demonstrated that patients were continuing to improve up to the 24-month mark, with limb symmetry indices ranging from 96.6–103.1 for the single-leg hop tests. Spearman's correlation coefficient demonstrated a significant relationship between the presence of ACL graft laxity and ACL-QOL score at 12- and 24-months post-operative (p < 0 .05). Functional performance on the single leg balance and single-leg hop tests demonstrated significant correlations to the 6-, 12- and 24-month ACL-QOL scores (p < 0 .05). There was no statistically significant correlation between the functional testing results and the presence of ACL graft laxity. This study demonstrated that up to 20.6% of patients had clinically measurable graft laxity 2-years after ACLR. In this cohort, patients with graft laxity demonstrated lower ACL-QOL scores, but did not demonstrate lower functional testing performance. Patient-reported ACL-QOL scores improved significantly at each time point following ACLR, and functional performance continued to improve up to 2-years after surgery. The ACL-QOL score was strongly correlated to the patient's ability to perform single-limb functional tests, indicating that the ACL-QOL score accurately predicted level of function

Objectives

The aim of this study was to investigate the biomechanical effect of the anterolateral ligament (ALL), anterior cruciate ligament (ACL), or both ALL and ACL on kinematics under dynamic loading conditions using dynamic simulation subject-specific knee models.

Aims

To investigate the risk factors for progression of articular cartilage damage after anatomical anterior cruciate ligament (ACL) reconstruction.

Aims

The aim of this retrospective multicentre study was to evaluate mid-term results of the operative treatment of Monteggia-like lesions and to determine the prognostic factors that influence the clinical and radiological outcome.

Joint laxity assessments have been a valuable resource in order to understand the biomechanics and pathologies of the knee. Clinical laxity tests like the Lachman test, Pivot-shift test and Drawer test are, however, subjective of nature and will often only provide basic information of the joint. Stress radiography is another option for assessing knee laxity; however, this method is also limited in terms of quantifiability and one-dimensionality. This study proposes a novel non-invasive low-dose radiation method to accurately measure knee joint laxity in 3D. A method that combines a force controlled parallel manipulator device, a medical image and a biplanar x-ray system. As proof-of-concept, a cadaveric knee was CT scanned and subsequently mounted at 30 degrees of flexion in the device and placed inside a biplanar x-ray scanner. Biplanar x-rays were obtained for eleven static load cases. The preliminary results from this study display that the device is capable of measuring primary knee laxity kinematics similar to what have been reported in previous studies. Additionally, the results also display that the method is capable of capturing coupled motions like internal/external rotation when anteroposterior loads are applied. We have displayed that the presented method is capable of obtaining knee joint laxity in 3D. The method is combining concepts from robotic arthrometry and stress radiography into one unified solution that potentially enables unprecedented 3D joint laxity measurements non-invasively. The method potentially eliminates limitations present in previous methods and significantly reduces the radiation exposure of the patient compared to conventional stress radiography

Aims

Our aim was to perform a meta-analysis of the outcomes of revision anterior cruciate ligament (ACL) reconstruction, comparing the use of different types of graft.

The Pivot-shift phenomenon (PS) is known to be one of the essential signs of functional insufficiency of the anterior cruciate ligament (ACL). To evaluate the dynamic knee laxity is very important to accurately diagnose ACL injury, to assess surgical reconstructive techniques, and to evaluate treatment approaches. However, the pivot-shift test remains a subjective clinical examination difficult to quantify. The aim of the present study is to validate the use of an innovative non-invasive device based on the use of an inertial sensor to quantify PS test. The validation was based on comparison with data acquired by a surgical navigation system. The surgeon intraoperatively performed the PS tests on 15 patients just before fixing the graft required for the ACL reconstruction. A single accelerometer and a navigation system simultaneously acquired the joint kinematics. An additional optical tracker set to the accelerometer has allowed to quantify the movement of the sensor. The tibial anteroposterior acceleration obtained with the navigation system was compared with the acceleration acquired by the accelerometer. It is therefore estimated the presence of any artifacts due to the soft tissue as the test-retest repositioning error in the positioning of the sensor. It was also examined, the repeatability of the acceleration parameters necessary for the diagnosis of a possible ACL lesion and the waveform of the output signal obtained during the test. Finally it has been evaluated the correlation between the two acceleration measurements obtained by the two sensors. The RMS (root mean square) of the error of test-retest positioning has reported a good value of 5.5 ± 2.9 mm. While the amounts related to the presence of soft tissue artifacts was equal to 4.9 ± 2.6 mm. It was also given a good intra-tester repeatability (Cronbach's alpha = 0.86). The inter-patient similarity analysis showed a high correlation in the acceleration waveform of 0.88 ± 0.14. Finally the measurements obtained between the two systems showed a good correlation (rs = 0.72, p<0.05). This study showed good reliability of the proposed scheme and a good correlation with the results of the navigation system. The proposed device is therefore to be considered a valid method for evaluating dynamic joint laxity

The aim of an anterior cruciate ligament (ACL) reconstruction is to regain functional stability of the knee following ACL injury, ideally allowing patients to return to their pre-injury level of activity. The purpose of this study was to assess clinical, functional and patient-centered outcomes a minimum of 1-year following ACL reconstruction. This study assessed for relationships between post-operative ACL graft laxity, functional testing performance, and scores on the ACL Quality of Life (ACL-QOL) questionnaire. A prospective cohort study design (n = 1938) was used to gather data on clinical laxity, functional performance and quality of life outcomes. Post-operative ACL laxity assessment using the Lachman and Pivot-shift tests was completed independently on each patient by a physiotherapist and an orthopaedic surgeon at a minimum of 12-months post-operatively. A battery of functional tests was performed including single leg balance, single leg landing, 4 single-leg hop tests, and tuck jumps. The hop tests provided a comparative assessment of limb-to-limb function including a single hop for distance, a 6m timed hop, a triple hop for distance, and a triple crossover hop. Patients com¬pleted the ACL-QOL at the 12-month and 24-month post-operative appointments. Descriptive and demographic data were collected for all patients. The degree and frequency of post-operative laxity was calculated. A Pearson r correlation coefficient was employed to determine the relationship between the presence of post-operative laxity and the ACL-QOL scores, between the battery of functional tests and the ACL-QOL scores, as well as between the functional tests and the laxity assessments. Data was gathered for 1512/1938 patients (78%). At clinical assessment a minimum of 1-year post-operatively, 13.2% of patients demonstrated a positive Lachman and/or Pivot-shift test. The mean ACL-QOL score for patients with no ACL laxity was 80.8/100, for patients with a positive Lachman or Pivot-shift test the mean score was 72.3/100, and for patients with both positive Lachman and Pivot-shift tests the score was 66.9/100. Pearson r correlation coefficient demonstrated a significant relationship between the presence of ACL graft laxity and ACL-QOL score (p < 0.05). Statistically significant correlations were evident between all of the operative limb single-leg hop tests and the post-operative ACL-QOL scores (p < 0.05). Statistically significant correlations were evident between the operative limb triple-hop tests and presence of ACL graft laxity (p < 0.05). Patients with clinically measurable ACL graft laxity demonstrate lower ACL-QOL scores as well as lower performance on a battery of functional tests. The disease-specific outcome measure was strongly correlated to the patient's ability to perform single-limb functional tests, indicating that the ACL-QOL score accurately predicted level of function

Aims

The purpose of this study was to report the experience of dynamic intraligamentary stabilisation (DIS) using the Ligamys device for the treatment of acute ruptures of the anterior cruciate ligament (ACL).

The December 2014 Knee Roundup³⁶⁰ looks at: national guidance on arthroplasty thromboprophylaxis is effective; unicompartmental knee replacement has the edge in terms of short-term complications; stiff knees, timing and manipulation; neuropathic pain and total knee replacement; synovial fluid α-defensin and CRP: a new gold standard in joint infection diagnosis?; how to assess anterior knee pain?; where is the evidence? Five new implants under the spotlight; and a fresh look at ACL reconstruction

We report the clinical outcome and findings at second-look arthroscopy of 216 patients (mean age 25 years (11 to 58)) who underwent anterior cruciate ligament (ACL) reconstruction or augmentation. There were 73 single-bundle ACL augmentations (44 female, 29 male), 82 double-bundle ACL reconstructions (35 female, 47 male), and 61 single-bundle ACL reconstructions (34 female, 27 male). In 94 of the 216 patients, proprioceptive function of the knee was evaluated before and 12 months after surgery using the threshold to detect passive motion test. Second-look arthroscopy showed significantly better synovial coverage of the graft in the augmentation group (good: 60 (82%), fair: 10 (14%), poor: 3 (4%)) than in the other groups (p = 0.039). The mean side-to-side difference measured with a KT-2000 arthrometer was 0.4 mm (-3.3 to 2.9) in the augmentation group, 0.9 mm (-3.2 to 3.5) in the double-bundle group, and 1.3 mm (-2.7 to 3.9) in the single-bundle group: the result differed significantly between the augmentation and single-bundle groups (p = 0 .013). No significant difference in the Lysholm score or pivot-shift test was seen between the three groups (p = 0.09 and 0.65, respectively). In patients with good synovial coverage, three of the four measurements used revealed significant improvement in proprioceptive function (p = 0.177, 0.020, 0.034, and 0.026). We conclude that ACL augmentation is a reasonable treatment option for patients with favourable ACL remnants. Cite this article: Bone Joint J 2014;96-B:1325–32

There have been differing descriptions of the anterolateral structures of the knee, and not all have been named or described clearly. The aim of this study was to provide a clear anatomical interpretation of these structures. We dissected 40 fresh-frozen cadaveric knees to view the relevant anatomy and identified a consistent structure in 33 knees (83%); we termed this the anterolateral ligament of the knee. This structure passes antero-distally from an attachment proximal and posterior to the lateral femoral epicondyle to the margin of the lateral tibial plateau, approximately midway between Gerdy’s tubercle and the head of the fibula. The ligament is superficial to the lateral (fibular) collateral ligament proximally, from which it is distinct, and separate from the capsule of the knee. In the eight knees in which it was measured, we observed that the ligament was isometric from 0° to 60° of flexion of the knee, then slackened when the knee flexed further to 90° and was lengthened by imposing tibial internal rotation.

Cite this article: Bone Joint J 2014;96-B:325–31.