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Oussedik S.,Sydney Orthopaedic Research Institute | Scholes C.,Sydney Orthopaedic Research Institute | Ferguson D.,Auckland City Hospital | Roe J.,Sports Medicine Center | Parker D.,Sydney Orthopaedic Research Institute
Clinical Orthopaedics and Related Research | Year: 2012

Background The position of the femoral component in a TKA in the axial plane influences patellar tracking and flexion gap symmetry. Errors in femoral component rotation have been implicated in the need for early revision surgery. Methods of guiding femoral component rotation at the time of implantation typically are derived from the mean position of the flexion-extension axis across experimental subjects. The functional flexion axis (FFA) of the knee is kinematically derived and therefore a patient-specific reference axis that can be determined intraoperatively by a computer navigation system as an alternative method of guiding femoral component rotation. However, it is unclear whether the FFA is reliable and how it compares with traditional methods. Question/purposes We asked if the FFA could be measured reproducibly at different stages of the operative procedure; (2) where it lies in relation to a CT-derived gold standard; and (3) how it compares with more traditional methods of judging femoral component rotation. Methods Thirty-seven patients undergoing elective TKAs were recruited to the study. Preoperative CT scans were obtained and the transepicondylar axis (TEA) was identified. The TKA then was performed using computer navigation. The FFA was derived before incision and again after the surgical approach and osseous registration. The navigation system was used to register the surgical TEA. The FFA and surgicalTEA then were comparedwith the CT-derived TEA. Results The mean preincision FFA was similar to the intraoperative FFA and therefore deemed reproducible. We observed no differences in variability between surgical TEA and preincision FFA. The FFA was different from the CTTEA and judged similar in accuracy to the surgical TEA. Conclusion The reliability and accuracy of the FFA were similar to those of other intraoperative methods. Further evaluation is required to ascertain whether the FFA improves on currently available methods for determining the ideal rotation of the femoral component during TKA. © The Association of Bone and Joint Surgeons® 2012.


Scholes C.J.,Sydney Orthopaedic Research Institute | Scholes C.J.,Queensland University of Technology | McDonald M.D.,Queensland University of Technology | Parker A.W.,Queensland University of Technology
Journal of Biomechanics | Year: 2012

Purpose: Evidence concerning the alteration of knee function during landing suffers from a lack of consensus. This uncertainty can be attributed to methodological flaws, particularly in relation to the statistical analysis of variable human movement data. The aim of this study was to compare single-subject and group analyses in detecting changes in knee stiffness and coordination during step landing that occur independent of an experimental intervention. Methods: A group of healthy men (N=12) stepped-down from a knee-high platform for 60 consecutive trials, each trial separated by a 1-minute rest. The magnitude and within-participant variability of sagittal stiffness and coordination of the landing knee were evaluated with both group and single-subject analyses. Results: The group analysis detected significant changes in knee coordination. However, the single-subject analyses detected changes in all dependent variables, which included increases in variability with task repetition. Between-individual variation was also present in the timing, size and direction of alterations. Conclusion: The results have important implications for the interpretation of existing information regarding the adaptation of knee mechanics to interventions such as fatigue, footwear or landing height. It is proposed that a participant's natural variation in knee mechanics should be analysed prior to an intervention in future experiments. © 2012 Elsevier Ltd.


Panteli M.,University of Leeds | Papakostidis C.,G Hatzikostas General Hospital | Dahabreh Z.,Sydney Orthopaedic Research Institute | Giannoudis P.V.,University of Leeds
Knee | Year: 2013

Background: To examine the safety and efficacy of topical use of tranexamic acid (TA) in total knee arthroplasty (TKA). Methods: An electronic literature search of PubMed Medline; Ovid Medline; Embase; and the Cochrane Library was performed, identifying studies published in any language from 1966 to February 2013. The studies enrolled adults undergoing a primary TKA, where topical TA was used. Inverse variance statistical method and either a fixed or random effect model, depending on the absence or presence of statistical heterogeneity were used; subgroup analysis was performed when possible. Results: We identified a total of seven eligible reports for analysis. Our meta-analysis indicated that when compared with the control group, topical application of TA limited significantly postoperative drain output (mean difference: -. 268.36. ml), total blood loss (mean difference. = -. 220.08. ml), Hb drop (mean difference. = -. 0.94. g/dL) and lowered the risk of transfusion requirements (risk ratio. = 0.47, 95CI. = 0.26-0.84), without increased risk of thromboembolic events. Sub-group analysis indicated that a higher dose of topical TA (>. 2. g) significantly reduced transfusion requirements. Conclusions: Although the present meta-analysis proved a statistically significant reduction of postoperative blood loss and transfusion requirements with topical use of TA in TKA, the clinical importance of the respective estimates of effect size should be interpreted with caution. Level of evidence: I, II. © 2013 Elsevier B.V.


Lustig S.,Sydney Orthopaedic Research Institute | Scholes C.J.,Sydney Orthopaedic Research Institute | Leo S.P.M.,Sydney Orthopaedic Research Institute | Coolican M.,Sydney Orthopaedic Research Institute | Parker D.A.,Sydney Orthopaedic Research Institute
Knee Surgery, Sports Traumatology, Arthroscopy | Year: 2013

Purpose: Despite increasing interest in the functional anatomy of the menisci, little information is available regarding the relationship between the tibial slope and the menisci. It was hypothesized that the meniscus would reduce the differences in slope between the medial and lateral compartments and would mitigate the effects of age and gender on the tibial slope. Methods: MRI sagittal images from 101 patients were used in this study. The angle between a line tangent to the medial and lateral tibial bony slope and the proximal tibial anatomical axis was measured on sagittal MRI images (bony slope). The angle between the tangent line to the highest point of the anterior and posterior horn of the meniscus and the proximal tibial anatomical axis was also determined (soft tissue slope). The measurements were carried out twice by two observers. The influence of gender and age on these parameters was analysed. Results: Repeated measures analysis of variance showed good inter- and intra-observer reliability for both bony and soft tissue slope (ICC (0. 87-0. 93) and (0. 91-0. 97) for inter- and intra-observer reliability, respectively). In both compartments, the soft tissue significantly reduced the tibial slope towards the horizontal plane. In addition, the soft tissue slope was significantly more horizontal in the lateral compartment compared to the medial compartment (p < 0. 01). These differences were not influenced by age or gender. Conclusion: The menisci of the knee generate a more horizontal tibial slope when measured on MRI. The soft tissue slope is more horizontal in the lateral compartment of the knee compared to the medial compartment. Level of evidence: Diagnostic, Level III. © 2012 Springer-Verlag.


Lustig S.,Sydney Orthopaedic Research Institute | Lustig S.,University of Lyon | Scholes C.J.,Sydney Orthopaedic Research Institute | Costa A.J.,Sydney Orthopaedic Research Institute | And 2 more authors.
Knee Surgery, Sports Traumatology, Arthroscopy | Year: 2013

Purpose: In contrast to radiographic measurements, MRI provides multiple slices of the knee joint in the sagittal plane, making it possible to assess the medial and lateral tibial slope separately. The purpose of this study is to investigate the effect of medial open-wedge high tibial osteotomy (MOWHTO) on bony and meniscal slope in the medial and lateral tibiofemoral compartments. It was hypothesised that greater changes on the medial tibial plateau would be observed compared with the lateral one. Methods: A retrospective analysis of prospectively collected data was performed on pre- and post-operative MRIs from 21 patients (17 men and 4 women; age 52 ± 9 years). Inclusion criteria were varus alignment, medial compartment osteoarthritis and election for a primary MOWHTO. Each patient had a preoperative and a post-operative high-resolution MRI (3Tesla, Magnetom Trio, Siemens AG) at an average follow-up of 2. 1 years. A previously published method was used to measure bony and meniscal slope for each compartment. The difference between pre- and post-operative tibial slope for both compartments was calculated and associated with the amount of frontal correction. Results: There was a significant increase in bony tibial slope in both compartments following MOWHTO. When a change in bony tibial slope was detected in an individual patient, the change was larger in the medial compartment, with the average change also significantly greater (p < 0. 01) in the medial compartment (2. 4° ± 1. 3°) compared with the lateral compartment (0. 9° ± 1. 1°). There was also a significant increase (p < 0. 01) in the lateral tibial meniscal slope of 0. 9° ± 1. 4°, which was equivalent to the change in the bony lateral slope. The amount of frontal correction was not significantly associated with the amount of change in slope. Conclusions: The results suggest that the modification of the bony slope is larger in the medial compartment after MOWHTO, which is likely related to the location of the hinge on the lateral tibial cortex. These findings suggest that consideration of the medial and lateral tibial slope intra-operatively could be important to identify the optimal location of the hinge. However, further studies are required before recommending any modification to the surgical technique, as the potential clinical consequences of tibial slope alterations remain unknown. Level of evidence: IV. © 2012 Springer-Verlag Berlin Heidelberg.


Oussedik S.,University College London | Tsitskaris K.,University College London | Parker D.,Sydney Orthopaedic Research Institute
Arthroscopy - Journal of Arthroscopic and Related Surgery | Year: 2015

Purpose We performed a systematic review of the treatment of articular cartilage lesions of the knee by microfracture or autologous chondrocyte implantation to determine the differences in patient outcomes after these procedures. Methods We searched PubMed/Medline, Embase, and The Cochrane Library databases in the period from January 10 through January 20, 2013, and included 34 articles in our qualitative analysis. Results All studies showed improvement in outcome scores in comparison with baseline values, regardless of the treatment modality. The heterogeneity of the results presented in the studies precluded a meta-analysis. Conclusions Microfracture appears to be effective in smaller lesions and is usually associated with a greater proportion of fibrocartilage production, which may have an effect on durability and eventual failure. Autologous chondrocyte implantation is an effective treatment that may result in a greater proportion of hyaline-like tissue at the repair site, which may in turn have a beneficial effect on durability and failure; it appears to be effective in larger lesions. Autologous chondrocyte implantation with periosteum has been shown to be associated with symptomatic cartilage hypertrophy more frequently than autologous chondrocyte implantation with collagen membrane. Matrix-associated autologous chondrocyte implantation is technically less challenging than the other techniques available, and in lesions greater than 4 cm2, it has been shown to be more effective than microfracture. Level of Evidence Level IV, systematic review of Level I-IV studies. © 2015 Arthroscopy Association of North America.


Scholes C.,Sydney Orthopaedic Research Institute | Sahni V.,Sydney Orthopaedic Research Institute | Lustig S.,Sydney Orthopaedic Research Institute | Lustig S.,University of Lyon | And 2 more authors.
Knee Surgery, Sports Traumatology, Arthroscopy | Year: 2014

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. © 2013 Springer-Verlag Berlin Heidelberg.


Parker D.A.,Sydney Orthopaedic Research Institute | Beatty K.T.,Sydney Orthopaedic Research Institute | Giuffre B.,Royal North Shore Hospital | Scholes C.J.,Sydney Orthopaedic Research Institute | Coolican M.R.J.,Sydney Orthopaedic Research Institute
American Journal of Sports Medicine | Year: 2011

Background: High tibial osteotomy (HTO) is a method used to treat medial compartmental osteoarthritis in the knee. The realignment of the knee changes the loading patterns within the joint and may allow for regeneration of articular cartilage. Magnetic resonance imaging methods can be used to assess the quality of the regenerated cartilage. Hypothesis: Altering mechanical alignment through HTO will have predictable effects on articular cartilage, allowing cartilage preservation and possible regeneration. Quality of regenerated cartilage will be inferior to normal articular cartilage. Study Design: Case series; Level of evidence, 4. Methods: Ten patients undergoing medial opening wedge HTO were evaluated using dGEMRIC methods (ie, delayed gadolinium-enhanced magnetic resonance imaging of cartilage) preoperatively and at 6 months, 1 year, and 2 years after HTO. Magnetic resonance images were evaluated by hand segmentation, and T1Gd relaxation times reflective of glycosaminoglycan content were determined for these regions of interest using magnetic resonance imaging analysis software. Results: The lateral compartment displayed higher T1Gd values than the medial compartment at baseline. Initially, a decrease in T1Gd values on the medial side were observed for all patients at 6 months and remained reduced for all but 2 participants at 1 year and 2 years after HTO. However, on the medial side after 6 months, the rate of change for T1Gd values shifted from being negative (-9.6 milliseconds per month) to being positive (1.7 milliseconds per month). A positive change in the T1Gd of the medial tibial plateau was responsible for the positive overall change in the medial compartment. There was no significant difference in the rate of change on the lateral side (P =.141), with the average over the 2-year period being a decrease of 2.28 milliseconds per month. Conclusion: Medial opening wedge HTO provides subjective improvements in pain and quality of life, but the potential benefit of allowing articular cartilage preservation and possible regeneration is not well established. Results showed that after a nonweightbearing period, the rate of change in the medial compartment changes from negative to positive, indicating the potential for articular cartilage recovery secondary to an improved mechanical environment. © 2011 The Author(s).


Lustig S.,Sydney Orthopaedic Research Institute | Lustig S.,University of Lyon | Scholes C.J.,Sydney Orthopaedic Research Institute | Scholes C.J.,Level Inc | And 4 more authors.
Journal of Arthroplasty | Year: 2013

This investigation evaluated the Smith and Nephew VISIONAIRE patient-specific cutting block (PSCB) system for total knee arthroplasty. A consecutive series of 60 patients was recruited. Intraoperative computer navigation was used to evaluate the accuracy of the cutting blocks in the coronal and sagittal planes for the tibia, as well as rotational plane for the femur. The PSCB would have placed 79.3% of the sample within ±3° of the preoperative plan in the coronal plane, while the rotational and sagittal alignment results within ±3° were 77.2% and 54.5% respectively. The VISIONAIRE PSCB system achieved unacceptable accuracy when assessed by computer navigation. There might be many sources of error, but caution is recommended before using this system routinely without objective verification of alignment. © 2013 Elsevier Inc.


Lustig S.,Sydney Orthopaedic Research Institute | Magnussen R.A.,Ohio State University | Dahm D.L.,Mayo Medical School | Parker D.,Sydney Orthopaedic Research Institute
Knee Surgery, Sports Traumatology, Arthroscopy | Year: 2012

Purpose: Patellofemoral arthroplasty remains controversial, primarily due to the high failure rates reported with early implants. Numerous case series have been published over the years detailing results of various first- and second-generation implants. The purpose of this work is to summarize results published to date and identify common themes regarding implants, surgical techniques, and indications in order to maximize results of future procedures. Methods: A comprehensive review of the MEDLINE database was carried out to identify all clinical studies related to patellofemoral arthroplasty. Results: First-generation resurfacing implants were associated with relatively high failure rates in the medium term. Second-generation implants, with femoral cuts based on TKA designs have yielded more promising medium-term results. Surgical indications are specific and must be carefully followed to minimize poor results. Short-term complications are generally related to patellar maltracking, while long-term complications are generally related to progression of osteoarthritis in the tibiofemoral joint. Implant loosening and polyethylene wear are rarely reported. Short-term results are favourable for new technology including custom implants and computer navigated surgery. Conclusions: Overall, recent improvements in implant design and surgical techniques have resulted in improvements in short- and medium-term results. More work is required to assess the long-term outcomes of modern implant designs. Level of evidence: IV. © 2012 Springer-Verlag.

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