Innovations in femoral tunnel positioning for anatomical ACL reconstruction

Contains fulltext : 156488.pdf (publisher's version ) (Open Access)RU Radboud Universiteit, 22 april 2016Promotor : Verdonschot, N.J.J. Co-promotor : Wymenga, A.B.244 p

Radiographic positions of femoral ACL, AM and PL centres: accuracy of guidelines based on the lateral quadrant method

Contains fulltext : 176916.pdf (publisher's version ) (Closed access)PURPOSE: Femoral tunnel positioning is an important factor in anatomical ACL reconstructions. To improve accuracy, lateral radiographic support can be used to determine the correct tunnel location, applying the quadrant method. Piefer et al. (Arthroscopy 28:872-881, 2012) combined various outcomes of eight studies applying this method to one guideline. The studies included in that guideline used various insertion margins, imaging techniques and measurement methods to determine the position of the ACL centres. The question we addressed is whether condensing data from various methods into one guideline, results in a more accurate guideline than the results of one study. METHODS: The accuracy of the Piefer's guideline was determined and compared to a guideline developed by Luites et al. (2000). For both guidelines, we quantified the mean absolute differences in positions of the actual anatomical centres of the ACL, AM and PL measured on the lateral radiographs of twelve femora with the quadrant method and the positions according to the guidelines. RESULTS: The accuracy of Piefer's guidelines was 2.4 mm (ACL), 2.7 mm (AM) and 4.6 mm (PL), resulting in positions significantly different from the actual anatomical centres. Applying Luites' guidelines for ACL and PL resulted in positions not significantly different from the actual centres. The accuracies were 1.6 mm (ACL) and 2.2 mm (PL and AM), which were significantly different from Piefer for the PL centres, and therefore more accurate. CONCLUSIONS: Condensing the outcomes of multiple studies using various insertion margins, imaging techniques and measurement methods, results in inaccurate guidelines for femoral ACL tunnel positioning at the lateral view. CLINICAL RELEVANCE: An accurate femoral tunnel positioning for anatomical ACL reconstruction is a key issue. The results of this study demonstrate that averaging of various radiographic guidelines for anatomical femoral ACL tunnel placement in daily practice, can result in inaccurate tunnel positions. LEVEL OF EVIDENCE: Diagnostic study, Level 1

Accuracy of a computer-assisted planning and placement system for anatomical femoral tunnel positioning in anterior cruciate ligament reconstruction

Background Femoral tunnel positioning is a difficult, but important factor in successful anterior cruciate ligament (ACL) reconstruction. Computer navigation can improve the anatomical planning procedure besides the tunnel placement procedure. Methods The accuracy of the computer-assisted femoral tunnel positioning method for anatomical double bundle ACL-reconstruction with a three-dimensional template was determined with respect to both aspects for AM and PL bundles in 12 cadaveric knees. Results The accuracy of the total tunnel positioning procedure was 2.7 mm (AM) and 3.2 mm (PL). These values consisted of the accuracies for planning (AM:2.9 mm; PL:3.2 mm) and for placement (about 0.4 mm). The template showed a systematic bias for the PL-position. Conclusions The computer-assisted templating method showed high accuracy for tunnel placement and has promising capacity for application in anatomical tunnel planning. Improvement of the template will result in an accurate and robust navigation system for femoral tunnel positioning in ACL-reconstructio

Stable fixation of the IBP humeral component implanted without cement in total elbow replacement: A radiostereometric analysis study of 16 elbows at two-year follow-up

Item does not contain fulltextWe determined the short-term clinical outcome and migration within the bone of the humeral cementless component of the Instrumented Bone Preserving (IBP) total elbow replacement in a series of 16 patients. There were four men and 12 women with a mean age at operation of 63 years (40 to 81). Migration was calculated using radiostereometric analysis. There were no intra-operative complications and no revisions. At two-year follow-up, all patients showed a significant reduction in pain and functional improvement of the elbow (both p < 0.001). Although ten components (63%) showed movement or micromovement during the first six weeks, 14 (88%) were stable at one year post-operatively. Translation was primarily found in the proximal direction (median 0.3 mm (interquartile range (IQR) -0.09 to 0.8); the major rotational movement was an anterior tilt (median 0.7 degrees (IQR 0.4 degrees to 1.6 degrees )). One malaligned component continued to migrate during the second year, and one component could not be followed beyond three months because migration had caused the markers to break off the prosthesis. This study shows promising early results for the cementless humeral component of the IBP total elbow replacement. All patients had a good clinical outcome, and most components stabilised within six months of the operation. Cite this article: Bone Joint J 2014;96-B:229-36

Computer-assisted anatomically placed double-bundle ACL reconstruction: An in vitro experiment with different tension angles for the AM and the PL graft

Anterior cruciate ligament reconstruction techniques are evolving with innovations like double-bundle (DB) grafts and computer assistance. The current DB techniques do not appear to make the clinical difference yet. Insight in various techniques may lead to better results. In this study, the anterior laxity of a DB reconstruction with an anteromedial (AM) graft fixated in 90° of flexion and a posterolateral (PL) graft fixated in 20° and computer-assisted anatomically placed femoral attachments was compared to normal values and single-bundle grafts. In 8 fresh-frozen human cadaveric knees, the anterior laxity was tested from 0° to 90° flexion, with a 100 Newton (N) anterior tibial load in joints with (1) intact ACL, (2) torn ACL, (3) single-bundle (SB) graft tensed with 15 N in 20°, (4) anatomic AM graft tensed with 15 N in 90°, (5) anatomic PL graft tensed with 15 N in 20°, and (6) anatomic DB graft (4 + 5).\ud \ud All reconstructions caused a posterior position of the tibia. Relative to the normal anterior laxity, the single-bundle techniques showed significantly increased laxities: The SB technique in 0° (+1.1 mm) and 15° (+1.7 mm); The AM reconstructions in 45° (+1.6 mm) and 90° (+1.5 mm); The PL reconstructions in all angles (from +1.4 to +2.3 mm), except in 0°. The anatomic DB technique showed no significantly increased laxities and restored normal laxity in all angles.\u

The insertion geometry of the posterolateral corner of the knee.

Contains fulltext : 48551.pdf (publisher's version ) (Closed access)We have quantitatively documented the insertion geometry of the main stabilising structures of the posterolateral corner of the knee in 34 human cadavers. The lateral collateral ligament inserted posterior (4.6 mm, sd 2) and proximal (1.3 mm, sd 3.6) to the lateral epicondyle of the femur and posterior (8.1 mm, sd 3.2) to the anterior point of the head of the fibula. On the femur, the popliteus tendon inserted distally (11 mm, sd 0.8) and either anterior or posterior (mean 0.84 mm anterior, sd 4) to the lateral collateral ligament. The popliteofibular ligament inserted distal (1.3 mm, sd 1.2) and anterior (0.5 mm, sd 2.0) to the tip of the styloid process of the fibula.The ligaments had a consistent pattern of insertion and, despite the variation between specimens, the standard deviations were less than the typical size of drill hole used in reconstruction of the posterolateral corner. The data provided in this study can be used in the anatomical repair and reconstruction of this region of the knee

Development of a femoral template for computer-assisted tunnel placement in anatomical double-bundle ACL reconstruction

Contains fulltext : 96804.pdf (publisher's version ) (Closed access)Femoral graft placement is an important factor in the success of anterior cruciate ligament (ACL) reconstruction. In addition to improving the accuracy of femoral tunnel placement, Computer Assisted Surgery (CAS) can be used to determine the anatomic location. This is achieved by using a 3D femoral template which indicates the position of the anatomical ACL center based on endoscopically measurable landmarks. This study describes the development and application of this method. The template is generated through statistical shape analysis of the ACL insertion, with respect to the anteromedial (AM) and posterolateral (PL) bundles. The ligament insertion data, together with the osteocartilage edge on the lateral notch, were mapped onto a cylinder fitted to the intercondylar notch surface (n = 33). Anatomic variation, in terms of standard variation of the positions of the ligament centers in the template, was within 2.2 mm. The resulting template was programmed in a computer-assisted navigation system for ACL replacement and its accuracy and precision were determined on 31 femora. It was found that with the navigation system the AM and PL tunnels could be positioned with an accuracy of 2.5 mm relative to the anatomic insertion centers; the precision was 2.4 mm. This system consists of a template that can easily be implemented in 3D computer navigation software. Requiring no preoperative images and planning, the system provides adequate accuracy and precision to position the entrance of the femoral tunnels for anatomical single- or double-bundle ACL reconstruction

The Dutch Multidisciplinary Occupational Health Guideline to Enhance Work Participation Among Low Back Pain and Lumbosacral Radicular Syndrome Patients

Purpose Based on current scientific evidence and best practice, the first Dutch multidisciplinary practice guideline for occupational health professionals was developed to stimulate prevention and enhance work participation in patients with low back pain (LBP) and lumbosacral radicular syndrome (LRS). Methods A multidisciplinary working group with health care professionals, a patient representative and researchers developed the recommendations after systematic review of evidence about (1) Risk factors, (2) Prevention, (3) Prognostic factors and (4) Interventions. Certainty of the evidence was rated with GRADE and the Evidence to Decision (EtD) framework was used to formulate recommendations. High or moderate certainty resulted in a recommendation "to advise", low to very low in a recommendation "to consider", unless other factors in the framework decided differently. Results An inventory of risk factors should be considered and an assessment of prognostic factors is advised. For prevention, physical exercises and education are advised, besides application of the evidence-based practical guidelines "lifting" and "whole body vibration". The stepped-care approach to enhance work participation starts with the advice to stay active, facilitated by informing the worker, reducing workload, an action plan and a time-contingent increase of work participation for a defined amount of hours and tasks. If work participation has not improved within 6 weeks, additional treatments should be considered based on the present risk and prognostic factors: (1) physiotherapy or exercise therapy; (2) an intensive workplace-oriented program; or (3) cognitive behavioural therapy. After 12 weeks, multi-disciplinary (occupational) rehabilitation therapy need to be considered. Conclusions Based on systematic reviews and expert consensus, the good practice recommendations in this guideline focus on enhancing work participation among workers with LBP and LRS using a stepped-care approach to complement existing guidelines focusing on recovery and daily functioning