Explore the vast range of titles available.

Purpose The introduction of patient-specific instruments (PSI) for guiding bone cuts could increase the incidence of malalignment in primary total knee arthroplasty. The purpose of this study was to assess the agreement between one type of patient-specific instrumentation (Zimmer PSI) and the pre-operative plan with respect to bone cuts and component alignment during TKR using imageless computer navigation. Methods A consecutive series of 30 femoral and tibial guides were assessed in-theatre by the same surgeon using computer navigation. Following surgical exposure, the PSI cutting guides were placed on the joint surface and alignment assessed using the navigation tracker. The difference between in-theatre data and the pre-operative plan was recorded and analysed. Results The error between in-theatre measurements and pre-operative plan for the femoral and tibial components exceeded 3° for 3 and 17 % of the sample, respectively, while the error for total coronal alignment exceeded 3° for 27 % of the sample. Conclusion The present results indicate that alignment with Zimmer PSI cutting blocks, assessed by imageless navigation, does not match the pre-operative plan in a proportion of cases. To prevent unnecessary increases in the incidence of malalignment in primary TKR, it is recommended that these devices should not be used without objective verification of alignment, either in real-time or with post-operative imaging. Further work is required to identify the source of discrepancies and validate these devices prior to routine use. Level of evidence II.

The aim of this study was to determine the reliability of bone landmarks for restoring the joint line in revision knee arthroplasty. The relationship of the femoral epicondyles, the tibial tubercle (TT) and the fibular head (FH) to the joint line was measured on 200 magnetic resonance imaging (MRI, 100 females, 100 males), including assessment on intraobserver and interobserver reliability. MRI scans demonstrating chondral lesions and osteoarthritis were excluded, as were patients with immature skeletons or a history of previous knee surgery. Sequences in sagittal, coronal and axial planes were used as well as cross-referencing with the same computer software. In order to account for size differences between patients, each bony landmark measurement was converted to a ratio relative to the femoral or/and tibial width. We found a transepicondylar axis equal to 3.11° (±1.9). The average distance from the epicondyles to the joint line was respectively 23 mm on the lateral side and 28 mm on the medial side. However there was a variation of distance from the epicondyles of the joint line up to 11 mm and a significative difference was found between male and female. We determined the distances from the tip of the FH and from the TT to the joint line. The joint line-FH distance averaged 14 mm (range 4.1–22.13) with no gender difference. The joint line-TT distance was averaged 22 mm (range 10.61–32.09). We determined an epicondylar ratio (distance from the lateral epicondyle to the joint line related to the femoral width). We found this ratio averaged 28% with no gender difference ( P  = 0.09). There is a large variation of bony landmarks depending on the size of the individual. Considering this findings, the FH is not a reliable guide for the joint line in revision surgery. Previous studies have measured the absolute values from various landmarks to the joint line. This study provides a significant advantage, in that the level of the joint line can be determined for each individual by using a ratio to account for gender and size differences.

Purpose Flexion contracture has been shown to impair function and reduce satisfaction following total knee arthroplasty (TKA). The aim of this study was to identify modifiable intra-operative variables that predict post-TKA knee extension. Methods Data was collected prospectively on 95 patients undergoing total knee arthroplasty, including pre-operative assessment, intra-operative computer assisted surgery (CAS) measurements and functional outcome including range of motion at one year. Patients were divided into two groups: those with mild flexion contracture (> 5°) at the one-year follow-up and those achieving full extension. Results The sagittal orientation of the distal femoral cut differed significantly between groups at the one-year follow-up ( p  = 0.014). Sagittal alignment of greater than 3.5° from the mechanical axis was shown to increase the relative risk of a mild flexion contracture at one-year follow-up by 2.9 times, independent of other variables. Conclusion Increasing the sagittal alignment of the distal femoral cut more than 3.5° from the mechanical axis is an independent risk factor for clinically detectable flexion contracture one year from index procedure.

The objective of the study was to evaluate the biomechanical and biological consequences of posterior cruciate ligament deficiency, determine compensatory mechanisms and assess the efficacy of non-operative treatment. Medline, CINAHL, SPORTdiscus, Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews were searched at 30th October 2006 for the terms \"PCL\" and \"posterior cruciate ligament\" both independently and including the terms \"injury\", \"deficiency\" and \"insufficiency\". Literature searches identified 598 potentially relevant articles, after exclusions there were 47 articles that fulfilled the inclusion criteria: 30 articles analyzing PCL deficiency and 17 studies on the outcomes for non-operative treatment. The authors reviewed all selected articles and abstracted data into predetermined tables depending upon classification. Studies indicate that posterior cruciate ligament deficiency results in posterior tibial translation with combined injuries displaying greater laxity. Results were inconsistent for rotational stability but deficiency increases joint contact pressure and may result in articular damage. A loss of proprioception occurs but the effect on strength and kinetics is inconclusive. There is a lack of evidence for compensatory muscle activity. Return to activity is possible for the majority of non-operatively treated grade I and II isolated injuries. Comparative analysis was not possible in many instances due to study design or experimental protocols. Further research is required to establish the compensatory mechanisms stabilizing the posterior cruciate ligament deficient knee and to investigate the outcomes for non-operatively treated patients.

Objectives: Matrix Induced Autologous Chondrocyte Implantation (MACI) has been reported to be an effective treatment for symptomatic cartilage defects with many studies finding improvements in pain and function. MACI in combination with HTO in the surgical management of varus malalignment with knee medial compartment cartilage loss improves clinical and MRI results beyond HTO alone. Methods: Twenty nine patients (n=31 knees) fulfilling HTO surgery inclusion criteria were prospectively enrolled and analysed in two groups: MACI+HTO (n=14); HTO-only (n=17). After a 12-months follow-up period, clinical scores (IKDC, KOOS and WOMAC) and Magnetic Resonance Imaging (MRI) assessment were analysed. MRI was firstly performed to evaluate the semi-quantitative Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Delayed Gadolinium Enhanced MRI of cartilage (dGEMRIC) protocol measuring T1Gd relaxation times was then use to assess the regenerated cartilage quality. Results: While significant improvement in clinical scores was found in both groups, the MACI+HTO group only demonstrated greater improvement in the symptoms sub-scale of KOOS (p<0.05) compared to the HTO-only group (p=0.016). The mean MOCART scores of the MACI+HTO patients was 34.6±14.8 [15-70] and a complete cartilage defect filling was confirmed in only 14.3% (n=2). Analysis of dGEMRIC images revealed no significant differences and a high between-subject variability in change of dGEMRIC indices across the follow-up period between groups. Conclusion: All knees, regardless of treatment, had significant clinical improvements at one-year post surgery. MACI may have additional clinical benefit in self-reported symptoms in the short term. Clinical improvements in patient scores are not explained by MRI findings that showed a poor structure of the repaired tissue in the majority of cases, and are most likely related solely to the HTO. Combined MACI+HTO had additional questionable clinical benefit in self-reported symptoms for patients with varus malalignment and knee medial compartment OA. For orthopaedic surgeons who may be contemplating this procedure, the additional cost and morbidities associated with the MACI graft is not justified.

Satisfaction from TKA arises from complex interrelated factors. Patients should be provided with adequate information regarding the nature of surgery and expected outcomes, and any discordance between the patient and surgeon expectations should be resolved. Group educational sessions and counselling by trained personnel can help in modifying preoperative variables for a successful outcome. As surgeons, it is our responsibility to provide satisfactory results by selecting appropriate patients, avoiding preventable complications and performing as technically perfect a surgical procedure as we can. A discussion of the risks of surgery and informed consent frequently involves the rare but well-acknowledged risks of sepsis, thromboembolic disease and inadvertent neurovascular injury. The literature tells us a dissatisfied patient is more common than all three together and this merits discussion before surgery.

Patellar resurfacing has been a debatable topic over the years. It is being increasingly used in certain countries and has fallen out of favour in some, due to conflicting registry and medical literature. The advantages have been well documented and are possibly the reason why many surgeons prefer doing it. There are a myriad of implants that are in the market with the dome-shaped, ultra-high molecular weight polyethylene implants being most favoured. Though initially introduced to decrease the incidence of anterior knee pain, the problem continues to exist in resurfaced patellae too.

Background: None of the anterolateral procedures used in combination with ACL reconstruction (ACLR) to control rotational laxity have demonstrated superiority. The objective was to compare the capacity of the main anterolateral procedures associated with ACLR to restore intact knee kinematics in case of combined ACL and anterolateral structure injury. Methods: The complete kinematics of 10 cadaveric knees, previously modelled by TDM, were recorded using a 3D Motion Analysis® system. Intact knee kinematics, including internal rotation (IR) of the tibial and anterior-posterior (AP) laxity at 30 and 90° flexion were initially assessed, followed by a sequential section of the ACL and anterolateral complex (ALC) (anterolateral ligament (ALL), ALL capsule and Kaplan fibers). After the ACLR, 5 anterolateral procedures were performed consecutively on the same knee: ALLR; Ellison; Deep Lemaire; Superficial Lemaire; and MacIntosh. The last three procedures were randomized. For each procedure, the graft was fixed in neutral rotation at 30° flexion with a tension of 20 N. Results: ACLR alone did not restore overall knee kinematics when there was an ACL+ALC injury, and resulted in residual rotational laxity of the tibia (p > 0.001). Only the ALLR (p=0.262) and modified Ellison (p=0.081) procedures restored normal global IR kinematics. Superficial/deep Lemaire and MacIntosh procedures resulted in over-constrained kinematic profiles (respectively: p=0.013, p=0.018 and p=0.030). In terms of ACLR, the addition of an anterolateral procedure did not provide additional control over AP translation at 30 and 90° (p > 0.05), exception for the surficial Lemaire procedure at 90° (p = 0.032). Discussion: ACLR alone was not sufficient to restore normal kinematics in ACL and ALC-deficient knees. ALLR and Ellison procedures restored physiological kinematics, unlike the MacIntosh procedure which caused additional control of IR and thereby induced over-constraint. Conclusion: The addition of ALLR or the modified Ellison procedure, which restore intrinsic kinematics, might be useful during primary ACL reconstruction to avoid repeated injury without a risk of over-constraint. The superficial/deep Lemaire and MacIntosh procedures resulted in over-constrained kinetics but provided additional rotation control that could be useful in revision surgery.