Abstract. Objectives. Little is known about the impact of cartilage defects on knee joint biomechanics. This investigation aimed to determine the gait characteristics of patients with symptomatic articular cartilage lesions of the knee. Methods. Gait analyses were performed at the Regional North-West Joint Preservation Centre. Anthropometric measurements were obtained, then 16 retroreflective markers representing the Plug-in-Gait biomechanical model were placed on pre-defined anatomical landmarks. Participants walked for two minutes at a self-selected speed on a treadmill on a level surface, then for 2 minutes downhill. A 15-camera motion-capture system recorded the data. Knee kinematics were exported into Matlab to calculate the average kinematics and spatiotemporal parameters per patient across 20 gait cycles. Depending on the normality of the data, paired t-tests or Wilcoxon ranked tests were performed to compare both knees (α = 0.05). Results. 20 patients participated; one of whom has bilateral cartilage defects. All 20 data sets were analysed for level walking; 18 were analysed for downhill walking. On a level surface, patients walked at an average speed of 3.1±0.8km/h with a cadence of 65.5±15.3 steps/minute. Patients also exhibited equal step lengths (0.470±0.072m vs 0.471±0.070m: p=0.806). Downhill, the average walking speed was 2.85±0.5km/h with a cadence of 78.8±23.1 steps/minute and step lengths were comparable (0.416±0.09m vs 0.420±0.079m: p=0.498). During level walking, maximum flexion achieved during swing did not differ between knees (54.3±8.6° vs 55.5±11.0°:p=0.549). Neither did maximal extension achieved at heel strike (3.1±5.7° vs 5.4±4.7°:p=0.135). On average, both knees remained in adduction throughout the gait cycle, with the degree of adduction greater in flexion in the operative knee. However, differences in maximal adduction were not significant (22.4±12.4° vs 18.7±11.0°:p=0.307). Maximal internal-external rotation patterns were comparable in stance (0.9±7.7° vs 3.5±9.8°: p=0.322) and swing (7.7±10.9° vs 9.8±8.3°:p=0.384). During downhill walking, maximum flexion also did not differ between operative and contralateral knees (55.38±10.6° vs 55.12±11.5°:p=0.862), nor did maximum extension at heel strike (1.32±6.5° vs 2.73±4.5°:p=0.292). No significant difference was found between maximum adduction of both knees (15.87±11.0° vs 16.78±12.0°:p=0.767). In stance, differences in maximum internal-external rotation between knees were not significant (5.39±10.7° vs 6.10±11.8°:p=0.836), nor were they significant in swing (7.69±13.3° vs 7.54±8.81°:p=0.963). Conclusions. Knee kinematics during level and downhill walking were symmetrical in patients with a cartilage defect of the knee, but an increased adduction during flexion in the operative knee may lead to pathological loading across the medial compartment of the knee during high flexion activities. Future work will investigate this further and compare the data to a healthy young population. We will also objectively assess the functional outcome of this joint preservation surgery to monitor its success. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Introduction and Objective. Malunion after trauma can lead to coronal plane malalignment in the lower limb. The mechanical hypothesis suggests that this alters the load distribution in the knee joint and that that this increased load may predispose to compartmental arthritis. This is generally accepted in the orthopaedic community and serves as the basis guiding deformity correction after malunion as well as congenital or insidious onset malalignment. Much of the literature surrounding the contribution of lower limb alignment to arthritis comes from cohort studies of incident osteoarthritis. There has been a causation dilemma perpetuated in a number of studies - suggesting malalignment does not contribute to, but is instead a consequence of, compartmental arthritis. In this investigation the relationship between compartmental (medial or lateral) arthritis and coronal plane malalignment (varus or valgus) in patients with post traumatic unilateral limb deformity was examined. This represents a specific niche cohort of patients in which worsened compartmental knee arthritis after extra-articular injury must rationally be attributed to malalignment. Materials and Methods. The picture archiving system was searched to identify all 1160 long leg x ray films available at a major metropolitan trauma center over a 12-year period. Images were screened for inclusion and exclusion criteria, namely patients >10 years after traumatic long bone fracture without contralateral injury or arthroplasty to give 39 cases. Alignment was measured according to established surgical standards on long leg films by 3 independent reviewers, and arthritis scores Osteoarthritis Research Society International (OARSI) and Kellegren-Lawrence (KL) were recorded independently for each compartment of both knees. Malalignment was defined conservatively as mechanical axis deviation outside of 0–20 mm medial from centre of the knee, to give 27 patients. Comparison of mean compartmental arthritis score was performed for patients with varus and valgus malalignment, using Analysis of Variance and linear regression. Results. In knees with varus malalignment there was a greater mean arthritis score in the medial compartment compared to the contralateral knee, with OARSI scores 5.69 vs 3.86 (0.32, 3.35 95% CI; p<0.05) and KL 2.92 vs 1.92 (0.38, 1.62; p<0.005). There was a similar trend in valgus knees for the lateral compartment OARSI 2.98 vs 1.84 (CI −0.16, 2.42; p=0.1) and KL 1.76 vs 1.31 (CI −0.12, 1.01; p=0.17), but the evidence was not conclusive. OARSI arthritis score was significantly associated with absolute MAD (0.7/10mm MAD, p<0.0005) and Time (0.6/decade, p=0.01) in a linear regression model. Conclusions. Malalignment in the coronal plane is correlated with worsened arthritis scores in the medial compartment for varus deformity and may similarly result in worsened lateral compartment arthritis in valgus knees. These findings support the mechanical hypothesis that arthritis may be related to altered stress distribution at the knee, larger studies may provide further conclusive evidence

Aim. The aim of this study is to outline the steps and techniques required to create a patient specific 3D printed guide for the accurate placement of the origin of the femoral tunnel for single bundle ACL reconstruction. Introduction. Placements of the femoral tunnels for ACL reconstruction have changed over the years. Most recently there has been a trend towards placing the tunnels in a more anatomic position. There has been subsequent debate as to where this anatomic position should be. The problem with any attempt at consensus over the placement of an anatomic landmark is that each patient has some variation in their positioning and therefore a fixed point for all has compromise for all as it is an average. Our aim was to attempt to make a cost effective and quick custom guide that could allow placement of the center of the patients’ newly created femoral tunnel in the mid position of their contralateral native ACL femoral footprint. Materials & Methods. We took a standard protocol MRI scan of a patient's knee without ACL injury transferred the DICOM files to a personal computer running OsiriX (Pixmeo, Geneva, Switzerland.) and analysed it for a series of specific anatomical landmarks. OsiriX is an image processing software dedicated to DICOM images. We marked the most posterior edge of the articular cartilage on the lateral wall of the notch (1), the most anterior edge of the articular cartilage of the lateral wall of the notch (2), the most inferior edge of the articular cartilage of the lateral wall of the notch (3) and the center of the femoral footprint of the native ACL. Distances were then calculated to determine the position relative to the three articular cartilage points of the center of the ACL footprint. These measurements and points were then utilised to create a 3D computer aided design (CAD) model of a custom guide. This was done using the 3D CAD program 123Design (Autodesk Ltd., Farnbourgh, Hampshire). This 3D model was then exported as an STL file suitable for 3D printing. The STL file was then uploaded to an online 3D printing service and the physical guide was created in transparent acrylic based photopolymer, PA220 plastic and 316L stainless steel. The models created were then measured using vernier calipers to confirm the accuracy of the final guides. Results. The MRI data showed point 1 (AP), point 2 (distal-ACL), point 3 (Ant-ACL) and point 4 (Post-ACL) at a distance of 59.83, 15, 45.8 and 13.9 respectively. For the 3D CAD model, points 1, 2, 3 and 4 were at a distance of 59.83, 15, 45.8 and 13.9 respectively. For the PA220 plastic model, points 1, 2, 3 and 4 were at a distance of 59.86, 14.48, 45.85 and 13.79 respectively. For the 316L stainless steel model, points 1, 2, 3 and 4 were at a distance of 59.79, 14.67, 45.64 and 13.48 respectively. Lastly, for the photopolymer model, points 1, 2, 3 and 4 were at a distance of 59.86, 14.2, 45.4 and 13.69 respectively. The p-value comparing MRI/CAD vs. PA220 was p=0.3753; for the comparison between MRI/CAD vs. 316L, p=0.0683; lastly for the comparison between MRI/CAD Vs. Photopolymer, p=0.3450. The models produced were accurate with no statistical difference in size and positioning of the center of the ACL footprint from the original computer model and to the position of the ACL from the MRI scans. The costs for the models 3D printed were £3.50 for the PA220 plastic, £15 for the transparent photopolymer and £25 for the 316L stainless steel. The time taken from MRI to delivery for the physical models was 7 days. Discussion. Articles regarding the creation of 3D printed custom ACL guides from the patients contralateral knee do not feature in current literature. There has been much research on custom guides for other orthopaedic procedures such as in total knee arthroplasty for the accurate placement of implants. There has also been research published on the creation of custom cutting jigs from CT for complex corrective osteotomy surgery. This study serves as the first step and a proof of concept for the accurate creation of patient specific 3D printed guides for the anatomical placement of the femoral tunnel for ACL reconstruction. The guides were easy to create and produce taking only a week and with a cost of between £3.50 and £25. The design of the guides was to allow the tip of a standard Chondro Pick (Arthrex inc., Naples, Florida.) (3mm) used to mark the starting point of the femoral tunnel to enter through the guide. The next step for this research is to create guides from cadaveric matched knees and utilise the guides to carry out the creation of the femoral tunnels and to analyse of the placement of the tunnel in relation to the contralateral knee

Introduction. Osteoarthritis (OA) is a slow progressive disease and a huge economic burden. A new target for therapy could be a growth factor treatment to prevent the loss of cartilage following injuries to the joint. BMP-7 is a promising candidate for such a novel therapy based on growth factors. In this study we combined the chondroprotective effects of BMP-7 with a novel thermosensitive hydrogel to prevent cartilage degeneration in a murine OA model. M&M. A BDI based thermosensitive hydrogel (Pluronic 123 with Butandiisyocyanate (BDI); LivImplant GmbH, Germany) was augmented with BMP-7 (rh-BMP-7, Olympus Biotech, France; 0.2 µg BMP-7/10µg Hydroge). To investigate the effects on OA progression we used the murine DMM (Destabilization of the medial meniscus) model for OA induction. Animal testing was approved by the Government Commitee of Upper Bavaria (file reference: 55.2-1-54-2532-150-13). A total of 38 C57BL/6 mice were included in this study. Immediately after the DMM surgery and wound closure BMP-7 mixed with BDI Hydrogel or only the BDI Hydrogel was administered via intraarticular injection. The following groups were examined: A) BMP-7 augmented BDI hydrogel B) only BDI hydrogel C) no injection following surgery D) control, healthy contralateral knee joint. After 4 (n=4 per group) and 8 (n=8) weeks mice were euthanized and knees were compared histologically. Results/Discussion. After 4 weeks the BMP-7 treated group showed a significant lower cartilage erosion compared to the group which only received DMM surgery. In the BMP-7 treated knee, osteoarthritis progression was also milder after 8 weeks than in knees of the DMM group. In all knees, except the control group, cartilage degeneration further progressed throughout the observation period. The contralateral joints showed no severe OA. We did not observe any inflammation or systemic reaction to the hydrogel. Taken together, we can conclude that BMP-7 showed a positive effect on the cartilage structure. Yet, the effect of a single administration is not strong enough to see a significant effect after 8 weeks. Furthermore, we can conclude, that the intraarticular administration of a thermosensitive hydrogel is an easy and feasible way to administer active agents precise to the joint

People with severe degenerative conditions, such as osteoarthritis (OA), have been shown to have altered movement patterns during sit-to-stand. However it remains unclear whether such alterations exist in people with early OA, in the absence of pain. This study aimed to determine if a novel seat could be used to discriminate people with early OA compared with controls. The sit-to-stand task was performed by 20 people with early medial knee OA and 20 age and gender-matched control subjects, using an instrumented seat. OA subjects showed altered weight distribution in the transition phase from sit to stand, in that they placed more load through their unaffected side. Task duration was also significantly longer for OA subjects. This study has demonstrated that a novel instrumented seat can be used to discriminate people with early medial knee OA during the sit-to-stand activity. These results may be relevant for early interventions to delay or prevent changes in muscle function of the affected limb as well as contralateral knee or hip osteoarthritis in these patients

Summary Statement. Objectifying postoperative recovery of patients with comminuted tibial plateau fractures treated with a unilateral plate trough the use of a gait analysis system. Introduction. Gait analysis has been a proved method for assessing postoperative results in patients with different orthopedic afflictions of the lower limb such as hallux valgus, ankle instabilities, knee osteoarthritis and arthroplasties but it has rarely been used for postoperative assessment of proximal tibial fractures. The more traditional means of quantifying postoperative articular step-off and limb axis deviations such as conventional X Rays and CT scanning and the clinician and patient completed scores that subjectively assess the outcome are complemented by the analysis of gait patterns set to objectify the most important patient related factor - the gait. As controversy exists in literature regarding the optimal treatment for severe tibial plateau fractures we proposed a gait study to evaluate locked angle unilateral plate osteosynthesis. Patient & Method: A computerised motion analysis system and a sensor platform were used to gather gait data from 15 patients with unilateral tibial plateau fractures graded Shatzker V and VI treated with a angular stable locked lateral plate osteosynthesis. Gait analysis was performed postoperatively based on patient availability and as soon as ambulation was possible and permitted without auxiliary support (crutches) at 4 (mean of 4,6), 6 (mean of 6,2) and 12 (mean of 11,7) months respectively, at a naturally comfortable walking. All patients were evaluated using classic anteroposterior and lateral knee radiography and were asked to fill the KOOS score questionnaire at the time of the gait analysis session. Results. The spatial-temporal and angular parameters revealed the expected postoperative decrease in ROM in both flexion and extension of the knee. Step and stance time objectively decreased between measuring session with an increase in single support of 3,7% mean value. A constant increase in walking speed was noted from a mean of 42 cm/sec (cadence of 31 st/min) at 4 months to a speed of 90 cm/sec (mean of 49 st/min cadence). We also determined a asymmetrical and wider walking base, increased area of support during single leg standing, decreased stance and increased swing phases for the injured knee compared to contralateral. Discussion. All patients in the study were subjectively satisfied with the results of the treatment, however we were able to detect quantifiable differences of gait parameters such between the injured and the contralateral knee such as step, stance and swing time and in knee flexion and adduction, combined with a modified, wider walking base. Ground reaction forces were strongly related to score improvement and thus directly reflected the healing at the fracture site

The discrepancy between successful experimental studies of cartilage repair and the clinical results is unexplained. We have evaluated the effect of metabolic alterations in joint homeostasis owing to an articular defect on the outcome of cartilage repair using tissue engineering methods. We used 21 adolescent Dutch goats divided into three groups. The control knees were left untreated while the contralateral knee was randomised to receive either no treatment (N), early treatment (E) or late treatment (L). The metabolism of proteoglycans in the surrounding joint surface was determined and correlated with the O’Driscoll score used to quantify the histological aspect of the repair of the defect. Synthesis of proteoglycan (PG) was increased in all groups. The release of glucosaminoglycan (GAG) was significantly higher in the untreated but not after early transplantation (1.3 v 1.8 NS). The cartilage repair scores in the early treatment group were not as good as those of the normal control group, but were significantly better when compared with both the untreated defects and the late treated defects. Defects which had been treated late showed a significantly decreased score when compared with those which had had early treatment or the normal control group and did not differ (p = 0.12) from those with no treatment. The histological and biochemical scores closely resembled the macroscopic and functional parameters which showed a significant deterioration for the late treated group and those without treatment compared with animals treated early. Thus, tissue-engineered cartilage repair is negatively influenced by altered matrix metabolism. Early treatment showed significantly better results for repair of cartilage than late or no treatment, with a concurrent decrease in the detrimental disturbance of cartilage metabolism which constituted a protective effect on the articulation

Background. Following an anterior cruciate ligament (ACL) injury, the affected knee is known to experience bone loss and is at significant risk of becoming osteoporotic. Surgical reconstruction is performed to attempt to restore the function of the knee and theoretically restore this bone density loss. Cross-sectional analysis of the proximal tibia using peripheral quantitative computed tomography (pQCT) enables localised analysis of bone mineral density (BMD) changes. The aim of this study was to establish the pattern of bone density changes in the tibia pre- and post- ACL reconstruction using pQCT image analysis. Methods. Eight patients who underwent ACL reconstruction were included. A cross sectional analysis of the proximal tibia was performed using a pQCT scanner pre-operatively and one to two years post-operatively on both the injured and contralateral (control) knee. The proximal two and three percent slices [S2 and S3] along the tibia were acquired. These were exported to Matlab(tm) and automated segmentation was performed to remove the tibia from its surrounding structures. Cross correlation was applied to co-register pairs of images and patterns of change in BMD were mapped using a t-test (p<0.05). Connected components of pixels with significant change in BMD were created and used to assess the impact of ACL injury & reconstruction on the proximal tibial BMD. Results. Prior to surgical ACL reconstruction, the BMD in the injured leg was significantly reduced relative to the control leg [S2: p=0.002, S3: p=0.002]. Post surgery, the proximal tibial BMD did not change in either leg [Control S2: p=0.102, S3: p=0.181; Injured S2: p=0.093, S3: p=0.439]. The post surgical images demonstrated patterns of increasing BMD surrounding the tunnel in the form of compact bone. Discussion. A significant reduction in proximal tibial BMD was observed in the ACL injured legs relative to control legs. The pattern of pre-operative bone loss was generally observed to be global across the entire slice. No change in BMD was observed following ACL reconstruction, in either injured or control leg. These results indicate that proximal tibial BMD is reduced and does not change after ACL reconstruction

Objectives

This study reports on a secondary exploratory analysis of the early clinical outcomes of a randomised clinical trial comparing robotic arm-assisted unicompartmental knee arthroplasty (UKA) for medial compartment osteoarthritis of the knee with manual UKA performed using traditional surgical jigs. This follows reporting of the primary outcomes of implant accuracy and gait analysis that showed significant advantages in the robotic arm-assisted group.

Objectives

In this study, we compared the pain behaviour and osteoarthritis (OA) progression between anterior cruciate ligament transection (ACLT) and osteochondral injury in surgically-induced OA rat models.

We attempted to repair full-thickness defects in the articular cartilage of the trochlear groove of the femur in 30 rabbit knee joints using allogenic cultured chondrocytes embedded in a collagen gel. The repaired tissues were examined at 2, 4, 8, 12 and 24 weeks after operation using histological and histochemical methods. The articular defect filling index measurement was derived from safranin-O stained sections. Apoptotic cellular fractions were derived from analysis of apoptosis in situ using TUNEL staining, and was confirmed using caspase-3 staining along with quantification of the total cellularity. The mean articular defect filling index decreased with time. After 24 weeks it was 0.7 (sd 0.10), which was significantly lower than the measurements obtained earlier (p < 0.01). The highest mean percentage of apoptotic cells were observed at 12 weeks, although the total cellularity decreased with time. Because apoptotic cell death may play a role in delamination after chondrocyte transplantation, anti-apoptotic gene therapy may protect transplanted chondrocytes from apoptosis.