The role of computer assisted navigation in revision surgery for failed anterior cruciate ligament reconstruction of the knee: A continuous series of 52 cases.

INTRODUCTION: The causes of failure of anterior cruciate ligament (ACL) reconstruction mainly involve incorrect tunnel positioning. There is no intraoperative tool allowing the surgeon to test graft biomechanics and to confirm that the new graft is in an optimal position. HYPOTHESIS: Control is improved with computer assisted navigation. MATERIAL AND METHODS: In this retrospective study, revision ACL reconstruction was performed with a new autologous graft in a continuous series of 52 failed ACL reconstructions. A computer assisted navigation system was used intraoperatively in all knees. Evaluation with this system confirmed the position of old and new tunnels as well as intraoperative laxity. RESULTS: Evaluation of tunnel position based on traditional radiological criteria found in the literature significantly underestimated graft biomechanics: 69% of the cases presented with unfavorable graft ansiometry (mean: 13 ± 2.2mm) while the correct position of the tibial tunnel was identified in 64% of cases on radiography and the femoral tunnel in 48%. All new grafts were optimally positioned by the computer assisted navigation system with a mean isometery of 3.2 (± 0.7) mm. Comparative pre- and postoperative evaluation of laxity showed a statistically significant improvement (P < 0.001): preoperative and postoperative Lachman test: 10.5 ± 2 mm and 3 ± 0.5, respectively; global rotational laxity: 24 ± 5° and 37 ± 7° respectively. CONCLUSION: The use of a computer assisted navigation system allows optimal positioning of the graft as well as a predictive assessment of laxity.

Posterior tibial slope accuracy with patient-specific cutting guides during total knee arthroplasty: A preliminary study of 50 cases.

BACKGROUND: Patient-specific cutting guides were recently introduced to facilitate total knee arthroplasty (TKA). Their accuracy in achieving optimal implant alignment remains controversial. The objective of this study was to evaluate postoperative radiographic outcomes of 50 TKA procedures with special attention to posterior tibial slope (PTS), which is difficult to control intraoperatively. We hypothesized that patient-specific cutting guides failed to consistently produce the planned PTS. MATERIAL AND METHODS: The Signature™ patient-specific cutting guides (Biomet) developed from magnetic resonance imaging data were used in a prospective case-series of 50 TKAs. The target PTS was 2°. Standardised digitised radiographs were obtained postoperatively and evaluated by an independent reader. Reproducibility of the radiographic measurements was assessed on 20 cases. The posterior cortical line of the proximal tibia was chosen as the reference for PTS measurement. Inaccuracy was defined as an at least 2° difference in either direction compared to the target. RESULTS: The implant PTS was within 2° of the target in 72% of knees. In the remaining 28%, PTS was either excessive (n=10; maximum, 9°) or reversed (n=4; maximum, -6°). The postoperative hip-knee-ankle angle was 0° ± 3° in 88% of knees, and the greatest deviation was 9° of varus. CONCLUSION: These findings support our hypothesis that patient-specific instrumentation decreases PTS accuracy. They are consistent with recently published data. In contrast, patient-specific instrumentation provided accurate alignment in the coronal plane.

Surgical management of combined anterior or posterior cruciate ligament and posterolateral corner tears: for what functional results?

INTRODUCTION: Management of combined anterior or posterior cruciate ligament and posterolateral corner tears is still poorly codified. The aim of this study was to evaluate functional outcome after complete surgical treatment. MATERIALS AND METHODS: This retrospective multicenter study included 53 patients. Mean age was 29.8 yrs. (15-49). The anterior and posterior cruciate ligaments were involved in respectively 48 and 5 cases. Mean time to surgery was 25.6 months (0-184), and in 10 cases less than 21 days. Nine patients were sedentary workers and 29 non-sedentary (13 laborers). All ligament injuries were treated surgically. Mean follow-up was 49 months (12-146). Last follow-up assessment used IKDC, Lysholm and KOOS scores. RESULTS: At last follow-up, IKDC score graded 14 patients A, 25 B, 8 C and 6 D, versus 0 A, 4 B, 25 C, 22 D and 2 ungraded preoperatively. Mean subjective IKDC and Lysholm scores were respectively 72.8 (11.5-100) and 77.5 (37-100). Mean KOOS scores (pain, symptoms, daily life, sports, quality of life) were respectively 78 (3-100), 70 (25-100), 88 (47-100), 53 (0-100) and 50 (0-100). Posterolateral laxity was corrected in all but two cases. All sedentary workers and 86.7% of non-sedentary workers could return to work. The job had to be changed in 10% of cases overall, but in 25% of cases for laborers. DISCUSSION: The present results are comparable with those of the literature. The strategy of combined surgical treatment showed functional efficacy, usually associated with return to work except for some laborers. There was a non-significant trend in favor of acute-phase ligament reconstruction. LEVEL OF EVIDENCE: IV (retrospective series).

Management of combined anterior or posterior cruciate ligament and posterolateral corner injuries: a systematic review.

BACKGROUND: Combined injuries to the posterolateral corner and cruciate ligaments are uncommon. The heterogeneity of injury patterns in many studies complicates the assessment of outcomes. OBJECTIVE: To assess the prognosis and functional outcomes after surgery for combined injuries to the posterolateral corner and to the anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL). MATERIAL AND METHODS: We systematically reviewed the literature for articles reporting outcomes 1 year or more after surgery for combined injuries to the posterolateral corner and ACL (n=4) or PCL (n=9). Patients with bicruciate injuries were not studied. RESULTS: Overall, 65% of patients were IKDC A or B after surgery. The mean Lysholm score improved from 67 to 90. Mean time to surgery was 4.43 months in the group with ACL tears and 18.4 months in the group with PCL tears, and mean follow-up was 34.4 and 40.7 months in these two groups, respectively. In the groups with ACL and PCL tears, the proportions of patients classified as IKDC A or B at last follow-up were 81.6% and 81.0%, respectively, whereas 88% and 99% of patients, respectively, were IKDC grade C or D before surgery. The mean Lysholm score improved from 77 to 92 in the group with ACL tears and from 65 to 89 in the group with PCL tears. Improvements in laxity ranged from 28% to 79% in the group with PCL tears. DISCUSSION: Most of the articles selected for our review provided level III or IV evidence. Functional outcomes were satisfactory but less good than those reported after surgical reconstruction of isolated cruciate ligament tears. Full reconstruction seems the best strategy in patients with combined ACL/posterolateral corner injuries. Outcomes were also good but more variable in the group with PCL/posterolateral corner injuries. The time to surgery, which reflected the time to diagnosis, was shorter in patients with ACL than with PCL tears in addition to the posterolateral corner injury. LEVEL OF EVIDENCE: Level III (systematic literature review).

Current concept in rotational laxity control and evaluation in ACL reconstruction.

Rotation combined with translation; compose the three-dimensional motion of the knee subluxation in anterior cruciate ligament deficient knee. The worldwide scientists were focused initially on the translation part of this complex 3D motion, but since the beginning of the century there was a large interest on knee rotational laxity study. Lot of paper reported new devices and results with an explosion since the beginning of the decade. The purpose of this review is to provide an extensive critical analysis of the literature and clarify the knowledge on this topic. We will start with a dismemberment of different rotational laxities reported: the rotation coupled with translation in 2D tests such as Lachman test and anterior drawer test; the rotational envelope considering the maximum internal external rotation; and the "active rotation" occurring in 3D Pivot-shift (PS) test. Then we will analyze the knee kinematics and the role of different anterior cruciate ligament (ACL) bundle on rotation. A review of different mechanical and radiological devices used to assess the different rotations on ACL deficient knees will be presented. Two groups will be analyzed, dynamic and static conditions of tests. Navigation will be described precisely; it was the starter of this recent interest in rotation studies. Opto electronic and electromagnetic navigation systems will be presented and analyzed. We will conclude with the last generation of rotational laxity assessment devices, using accelerometers, which are very promising.

Evaluation of a computer-assisted navigation system for anterior cruciate ligament reconstruction: prospective non-randomized cohort study versus conventional surgery.

BACKGROUND: Conventional reconstruction of the anterior cruciate ligament (ACL) is associated with a 15% failure rate. Computer-assisted navigation systems (CANS) have been developed to improve the accuracy of tunnel positioning. HYPOTHESIS: The use of a CANS for ACL reconstruction decreases the rate of failure, defined as IKDC grade C or D, compared to conventional ACL reconstruction. MATERIALS AND METHODS: This prospective multicentre observational non-randomised open study compared two groups of patients requiring arthroscopic ACL reconstruction: one group was managed with a CANS and the other (control group) without a CANS. The primary evaluation criterion was based on the subjective and objective IKDC scores. Inclusion criteria were age older than 18 years and first ACL reconstruction procedure using autologous semitendinosus and gracilis tendons or an autologous bone-patellar tendon-bone graft. Of the 272 included patients, 214 were analysed; 100 were in the control group and 114 in the CANS group. RESULTS: No significant between-group differences were found for the fraction of patients having an IKDC grade A or B (P=0.953), the subjective IKDC score (P=0.77), differential knee laxity at 150 N (1.38 ± 1.79 mm in the control group and 1.77 ± 2.06 mmin the CANS group, P=0.384), graft-type, or graft positioning. DISCUSSION: Our results establish the large-scale feasibility of computer-assisted navigation for ACL reconstruction. However, the main outcomes at 1 year showed no significant differences between patients managed with and without computer-assisted navigation.

Morphometric analysis and functional correlation of tibial and femoral footprints in anatomical and single bundle reconstructions of the anterior cruciate ligament of the knee.

INTRODUCTION: The anterior cruciate ligament (ACL) is composed of an infinite number of fibers whose individual anatomical and biomechanical features have been well defined. Although numerous biomechanical studies have shown that reconstruction that is as anatomical as possible results in better control of rotational laxity, very few studies have investigated the surface area of tibial and femoral insertion sites in these reconstructions. The aim of this study was to compare the surface areas of tibial and femoral insertion sites in single and double bundle reconstructions and correlate these findings with the isometry profile obtained. Our hypothesis was that double bundle (DB) reconstruction results in better filling of the native ACL footprint thus increasing the biomechanical value of available graft tissue. PATIENTS AND METHODS: Forty-six patients underwent computer navigated ACL using hamstring tendons: 23 underwent single bundle (SB) and 23 DB reconstruction. The Praxim navigation station equipped with ACL logics software made it possible to digitize insertion site footprints, register perioperative data for graft position as well as anteroposterior and rotational laxities and pivot shift. RESULTS: There was a statistically significant difference between the two groups for tibial and femoral insertion site surface areas: 71 mm(2) ± 17 (SB) versus 99.9 mm(2) ± 30 (DB) for the tibia, 67 ± 11 mm(2) (SB) versus 96.9 mm(2) ± 28 (DB) for the femur. Isometry profiles showed that anisometry was favorable in all cases: 2.5 mm ± 2 for SB; 2.9 mm ± 2 for the anteromedial bundle (AMB) with DB and 9.6 mm ± 3.7 for the posterolateral bundle. When both groups were combined, there was a statistically significant correlation between the size of tibial insertion surface area and anteroposterior and rotational laxity. DISCUSSION: This study confirms that better filling of native ACL footprint surface areas results in better control of anteroposterior laxity. LEVEL OF EVIDENCE: Level IV.

Analysis of anatomic positioning in computer-assisted and conventional anterior cruciate ligament reconstruction.

INTRODUCTION: Anterior cruciate ligament (ACL) reconstruction should be anatomic while achieving favorable anisometric behavior to avoid impingement with the femoral notch. Computerization enables these biomechanical conditions to be optimally fulfilled; but what of anatomic positioning? The present study compared the positioning of tibial and femoral tunnels, drilled using either a conventional ACL guide or a navigation system, using the anatomic foot-print areas of the native ACL. MATERIAL AND METHODS: This cadaver study used computerized recording to compare tibial and femoral ACL attachment areas to the positioning of tunnels created either conventionally or under computer-guided navigation. RESULTS: Computer guidance enabled the tibial and femoral tunnels to be systematically positioned within the anatomic area and, as regards the tibial area, within the anterior third near to the medial tibial spine, without femoral notch impingement. Anisometry was in all cases favorable, at a mean 3.3 ± 0.7 mm; using a conventional guide, anisometry was favorable in only 50% of cases, at a mean 5.4 ± 1.2 mm. CONCLUSION: Computer-guided navigation ensured implant positioning within the so-called anatomometric area of the native ACL attachment, avoiding impingement with the femoral notch. LEVEL OF EVIDENCE: Level 2.

Anterior cruciate ligament reconstruction: assessment of the hamstring autograft femoral fixation using the EndoButton CL.

UNLABELLED: The objective of this study was to evaluate the clinical and radiological results of a prospective, continuous series of 105 ACL reconstructions using the STG tendons fixed to the femur by an EndoButton CL, with more than 4 years of follow-up. HYPOTHESIS: The subjective and objective clinical results as well as the radiological results (tunnel enlargement) obtained by a cortical, extra-anatomic femoral fixation are at least equivalent to the results obtained with other types of femoral fixation systems. MATERIAL AND METHODS: One hundred and five patients aged with a mean 26 years (range, 12-56 years) were operated on for an anterior cruciate ligament rupture using the same technique and by the same operator: four-strand STG fixed to the tibia by a double fixation--BioRCI-HA screw and staple--and on the femur by an EndoButton CL (Smith and Nephew). The results were assessed at 6 months, 1 and 2 years and then at a mean follow-up of 51 months, both clinically (IKDC, Lysholm, KT-1000) and radiologically (Telos laximetry, tunnel position, and morphological analysis). RESULTS: No complications related to the use of the EndoButton were observed. No additional interference screw was necessary. According to the IKDC laxity classification, 91.4% of the patients were classified in category A or B, nine knees (8.6%) were classified C or D. Four failures required revision with a patellar tendon graft. On the final IKDC score, 63 patients (60%) were classified grade A, 37 grade B (35.3%), four grade C (3.8%), and one grade D (0.9%). On the Telos laximetry, 62 patients (59%) had a differential laxity less than or equal to 2 mm. The mean value was 1.8 mm (range, 0-11). Tibial tunnel enlargement was constant; femoral tunnel enlargement was significant (>2 mm) in 27.6% of the knees. No femoral tunnel diameter modification corresponding to the EndoButton passage was observed. DISCUSSION: The results of this series are comparable to the results of other series. Its reproducibility and the absence of iatrogenic complications for this femoral EndoButton CL fixation make it a top-choice technique, like the corticocancellous graft procedures, but without their disadvantages. No secondary elongation attributable to the EndoButton CL was observed. This femoral fixation procedure appeared necessary and sufficient to providing good mechanical stability for the graft in the femoral tunnel.

Fluoroscopy-based navigation system in spine surgery.

The variability in width, height, and spatial orientation of a spinal pedicle makes pedicle screw insertion a delicate operation. The aim of the current paper is to describe a computer-assisted surgical navigation system based on fluoroscopic X-ray image calibration and three-dimensional optical localizers in order to reduce radiation exposure while increasing accuracy and reliability of the surgical procedure for pedicle screw insertion. Instrumentation using transpedicular screw fixation was performed: in a first group, a conventional surgical procedure was carried out with 26 patients (138 screws); in a second group, a navigated surgical procedure (virtual fluoroscopy) was performed with 26 patients (140 screws). Evaluation of screw placement in every case was done by using plain X-rays and post-operative computer tomography scan. A 5 per cent cortex penetration (7 of 140 pedicle screws) occurred for the computer-assisted group. A 13 per cent penetration (18 of 138 pedicle screws) occurred for the non computer-assisted group. The radiation running time for each vertebra level (two screws) reached 3.5 s on average in the computer-assisted group and 11.5 s on average in the non computer-assisted group. The operative time for two screws on the same vertebra level reaches 10 min on average in the non computer-assisted group and 11.9 min on average in the computer-assisted group. The fluoroscopy-based (two-dimensional) navigation system for pedicle screw insertion is a safe and reliable procedure for surgery in the lower thoracic and lumbar spine.

Bone morphing: 3D morphological data for total knee arthroplasty.

OBJECTIVE: The clinical outcome of a total knee arthroplasty (TKA) is mainly determined by the accuracy of the surgical procedure itself. To improve the final result, one must take into account (a) the alignment of the prosthesis with respect to the mechanical axis, and (b) the balance of the soft tissues. Therefore, morphologic data (such as the shape of the epiphysis) and geometric data are essential. We present a new method for performing TKA based on morphologic and geometric data without preoperative images. MATERIALS AND METHODS: The global method is based on the digitization of points with an optical 3D localizer. For the morphologic acquisitions, we use a method based on the registration of sparse point data with a 3D statistical deformable model. To build the mechanical axis, we use a kinematics method for the hip center and digitization of anatomical landmarks for the ankle centers. The knee center is not determined by digitization or kinematics of the knee, as this would not be accurate. The surgical planning relies totally on the soft-tissue balance, which is the key issue for a good kinematics result. RESULTS: We have used this system for 6 months in a randomized clinical trial involving 35 patients to date. For the first 11 patients that could be measured in the navigation group, the postoperative frontal alignment was within the range of 180 +/- 3 degrees. Fluoroscopic assessment of the soft-tissue balancing will be performed at the conclusion of an extended 2-year study to evaluate the results from a functional point of view. CONCLUSION: Bone Morphing is an accurate, fast, and user-friendly method that can provide morphologic as well as geometric data. We have introduced the important notion of soft-tissue balancing into the intraoperative planning step to optimize the kinematics as well as the anatomy. Therefore, this method should be considered as an alternative to the CT-based method.

[Primary bone leiomyosarcoma. Anatomo-clinical case with immunohistochemistry study and review of the literature]. / Le léiomyosarcome osseux primitif. Une observation anatomoclinique avec étude immunohistochimique et revue de la littérature.

We describe a primary leiomyosarcoma arising in the proximal part of the right tibia of a 38-year-old man. The diagnosis was confirmed by immunohistochemistry (positivity of tumor cells for alpha smooth muscle actin, HHF 35, desmin and vimentin). To the best of our knowledge, this is the 49th documented case of primary leiomyosarcoma of bone outside the facial skeleton. This exceptional tumor arises more commonly in adults (mean age: 53 years) and in the long bones of lower limbs, near the knee. The most frequent symptom is pain with or without swelling or fracture. Radiological findings invariably consist of a non specific osteolytic lesion. Although their histological appearance does not differ from that of extraosseous leiomyosarcomas, their diagnosis is difficult and often requires immunohistochemical and/or ultrastructural study. From a practical point of view, the diagnosis of primary leiomyosarcoma of bone also requires an intensive review of the case history and of previous pathology. This is necessary in order to eliminate an extraosseous primary site (mainly in uterus, gastrointestinal tract and soft tissues). As well as clinicopathological features, modes of treatment and results are also reviewed.