A computed tomography based study on rotational alignment accuracy of the femoral component in total knee arthroplasty using computer-assisted orthopaedic surgery

Rotation of the femoral component in total knee arthroplasty (TKA) is of high importance in respect of the balancing of the knee and the patellofemoral joint. Though it is shown that computer assisted surgery (CAOS) improves the anteroposterior (AP) alignment in TKA, it is still unknown whether navigation helps in finding the accurate rotation or even improving rotation. Therefore the aim of our study was to evaluate the postoperative femoral component rotation on computed tomography (CT) with the intraoperative data of the navigation system. In 20 navigated TKAs the difference between the intraoperative stored rotation data of the femoral component and the postoperative rotation on CT was measured using the condylar twist angle (CTA). This is the angle between the epicondylar axis and the posterior condylar axis. Statistical analysis consisted of the intraclass correlation coefficient (ICC) and Bland-Altman plot. The mean intraoperative rotation CTA based on CAOS was 3.5° (range 2.4–8.6°). The postoperative CT scan showed a mean CTA of 4.0° (1.7–7.2). The ICC between the two observers was 0.81, and within observers this was 0.84 and 0.82, respectively. However, the ICC of the CAOS CTA versus the postoperative CT CTA was only 0.38. Though CAOS is being used for optimising the position of a TKA, this study shows that the (virtual) individual rotational position of the femoral component using a CAOS system is significantly different from the position on a postoperative CT scan

Three-Dimensional Printed Models in Pre-Operative Planning of Complex Primary and Revision Total Knee Arthroplasty

Three-dimensional (3D) printing was introduced firstly for industrial use, but it gained popularity in different medical fields, including orthopedic surgeries. Particularly, 3D-printed models have been used in the pre-operative planning for spine surgery, oncology, acetabular fracture treatment and complex primary total hip arthroplasty (THA) or revision THA. In knee surgery, some authors described good accuracy with 3D-printed wedge for Opening Wedge High Tibial Osteotomy (OWHTO), but there are no studies describing its application in Total Knee Arthroplasty (TKA). In both primary and revision TKA, a 3D-printed model may be useful to better evaluate knee morphology and deformity, implants, bone losses and the compatibility between different components used. Furthermore, some companies provide a bone thickness evaluation, which may be useful to identify zones at risk of intra-operative fracture, especially in those cases in which a cone or sleeve must be used. The first aim of this manuscript was to evaluate possible application of 3D-printed model in pre-operative planning of both complex primary and revision TKA, compared to standard planning. Two clinical cases will also be described to show how these models can be used for planning purposes

Computer-Assisted Surgery Enables Beginner Surgeons, Under Expert Guidance, to Achieve Long-Term Clinical Results not Inferior to Those of a Skilled Surgeon in Knee Arthroplasty

Purpose: The purpose of this study is to determine whether the use of a surgical navigation system in total knee replacement (TKR) enables beginner and intermediate surgeons to achieve clinical PROM outcomes as good as those conducted by expert surgeons in the long term. Methods: We enrolled 100 consecutive patients whose total navigated knee arthroplasty (TKA) was performed in our institution from 2008 to 2010. According to the principal surgeon's surgical experience, the patients were divided into three groups: (1) beginner surgeons, with no more than 30 previous knee replacement performances, (2) intermediate surgeons, with more than 30 but not more than 300, and (3) expert surgeons, with more than 300 knee replacements. Demographic data collected on the cohort included gender, laterality, age, and body mass index (BMI). The outcome measures assessed were Forgotten Joint Score (FJS), implant positioning, limb alignment, and prosthesis survival rate. A margin of equivalence of±18.5 points in the FJS scale was prespecifed in terms of the minimal clinically important diference (MCID) to compare the FJS results obtained in the long period between the groups of interest. Results: The mean follow-up was 11.10±0.78, 10.86±0.66, and 11.30±0.74 years, respectively, for each of the groups. The long-term FJS mean score was 80.86±21.88, 81.36±23.87, and 90.48±14.65 for each group. The statistical analysis proved noninferiority and equivalence in terms of the FJS results reported in the long term by patients in Groups 1 or 2 compared to those in Group 3. More specifcally, it has been proved that the mean diference between groups is within the interval of equivalence defned in terms of the MCID. The overall prostheses survival rate was 93.7%. Conclusion: Navigated assisted TKA, under expert guidance, can be as efective when performed by beginner or intermediate surgeons as performed by senior surgeons regarding the accuracy of implant positioning, limb alignment, and long-term clinical outcome

Personalized Hip and Knee Joint Replacement

This open access book describes and illustrates the surgical techniques, implants, and technologies used for the purpose of personalized implantation of hip and knee components. This new and flourishing treatment philosophy offers important benefits over conventional systematic techniques, including component positioning appropriate to individual anatomy, improved surgical reproducibility and prosthetic performance, and a reduction in complications. The techniques described in the book aim to reproduce patients’ native anatomy and physiological joint laxity, thereby improving the prosthetic hip/knee kinematics and functional outcomes in the quest of the forgotten joint. They include kinematically aligned total knee/total hip arthroplasty, partial knee replacement, and hip resurfacing. The relevance of available and emerging technological tools for these personalized approaches is also explained, with coverage of, for example, robotics, computer-assisted surgery, and augmented reality. Contributions from surgeons who are considered world leaders in diverse fields of this novel surgical philosophy make this open access book will invaluable to a wide readership, from trainees at all levels to consultants practicing lower limb surger

Implant alignment following total knee arthroplasty : a quality indicator for the intra-operative performance of the operating team

Evidence of inadvertent patient harm due to healthcare staff errors - both within the NHS and in other healthcare providers worldwide - prompted regulator-led changes to eliminate such distressing incidents to patients and medical staff alike. Surgical disciplines, including orthopaedic surgery, became a focus of attention given the scale of the problem within operating theatres. Orthopaedic theatres are an example of a complex working environment that has been likened to an airplane cockpit whereby the delivery of unsafe and low quality service can lead to highly significant consequences. Around 32.6% of all surgical patient safety incidents reported by the NPSA are related to orthopaedics. Evidence suggests that harm incidents are influenced by the surgical team’s non-­‐technical skills, and can occur through an unpredicted combination of small, seemingly innocuous everyday events. It is also suggested that non-technical factors including the non-technical skills of the operating team can influence the technical tasks during surgery. In elective orthopaedic surgery, one important technical task during TKA surgery is achieving a neutral limb alignment making it a suitable surrogate for technical success and quality indicator for intra-operative performance. The impact of malalignment on patient outcomes is not fully understood. A systematic review of the literature demonstrated that although malalignment appears to associate with poor procedure outcomes however, the evidence in the literature to support this conclusion is subject to several limitations. There is also variability in the assessment methods qualities and a checklist to assess the radiological assessment methods is presented. Malalignment on the coronal plane is regarded as the most significant in determining long term implant survival. A novel X-­‐ray method using custom made jig and trigonometry principles designed during this thesis has demonstrated higher agreement with CT scan than the commonly used conventional short leg X-­‐rays in assessing coronal malalignment; (95% Limits of agreement = -­‐3.616867 to 3.616867 for novel technique versus -­‐6.333201 to 5.754254 for conventional short leg X-­‐rays). In order to explore the relationship between non-­‐technical factors and technical success, successive TKAs were observed to collect data on surgical team’s non-­‐ technical performance and the number of unwanted events. 3D malalignment was assessed using a low dose CT. Parson’s correlation and regression analysis showed that better overall limb alignment following TKA correlates significantly with better intra-­‐operative non-­‐technical skills measured using the Oxford NOTECHS II score (r=-­‐ 0.407, p=0.01), and not with eventless procedures (measured by the glitch count). The surgical teams’ non-­‐technical skills play a significant role in the team’s ability to carry out technical tasks. If we are to provide optimal patient care we need to invest in improving non-­‐technical skills in the theatre

CAOS & TKA. A critical appraisal on computer navigation in total knee arthroplasty

In mijn proefschrift heb ik onderzocht wat de invloed is van het gebruik van navigatie bij het plaatsen van een knieprothese. Hiervoor zijn drie onderzoeksvragen opgesteld en beantwoord. Allereerst: leidt CAOS tot het nauwkeuriger plaatsen van een TKP? Op basis van de door mij gedane studies en analyse van de huidige literatuur concludeer ik dat juiste registratie tijdens CAOS essentieel is voor het bereiken van een goede stand van de TKP. Zolang hier nog onnauwkeurigheden in zitten leidt CAOS (nog) niet tot het nauwkeuriger plaatsen van de TKP, met name wat betreft de rotatie van de femurcomponent. Daarnaast heb ik onderzocht of CAOS leidt tot een juiste maatvoering van de TKP en patella tracking. Ik kom tot de conclusie dat men uit moet kijken voor het plaatsen van met name een te grote femurcomponent. De data die verkregen zijn middels het gebruik van de patella tracking module worden significant be_nvloed door de snelheid van bewegen van de knie en de zichtbaarheid van een markertree. Tot slot is bekeken wat de klinische en radiologische uitkomst is van een TKP geplaatst met CAOS. Hoewel er aanwijzingen zijn dat het aantal outliers wat betreft het alignment van de TKP met CAOS afneemt, kan er geen relatie aangetoond worden met de klinische uitkomst van de prothese. Momenteel is CAOS een bruikbare techniek voor onderzoeksdoeleinden, zoals de chirurgische techniek en kinematische analyse, en als onderwijsinstrument. Verder onderzoek is nodig om de exacte plaats van CAOS bij het plaatsen van TKP te bepalen. Tot die tijd moet men kritisch blijven wat betreft de toepassing van nieuwe technieken in de Orthopaedische Chirurgie, deze gefaseerd invoeren en de vraag stellen of iets een __tool__ of een __toy__ is.UBL - phd migration 201

Study of Coronal Alignment of Knee after Total Knee Replacement

INTRODUCTION: The surgeon performing a total knee arthroplasty is not only concerned with the early pain relief to the arthritic patient but should also provide the patient with stable functional knee with the maximum implant survival. Survivorship for cemented total knee arthroplasty ranges between 91% and 99% at ten years and between 91% and 96% at 15 years. Several studies have concluded that durability of the total knee replacement is dependent on the postoperative axial alignment of the lower extremity. If replacement of the knee leaves the extremity in varus or valgus mal-alignment, loosening and instability occurs at a greater rate than if the limb is well aligned by arthroplasty. Mal-alignment leads to overload of the bone and ligaments, leading to asymmetric bone loss, prosthetic wear and fracture and ligamentous instability. Preoperative axial alignment of the lower extremity is essential to assess the bony cuts to be taken during surgery as well as the ligamentous balancing to be performed intra operatively. Hence assessment of axial alignment before and after surgery is imperative in any patient undergoing a knee replacement surgery. AIM: The aim of the study is to compare the axial alignment of the lower extremity before and after surgery in patients undergoing total knee replacement by assessing the mechanical axis in the full length weight bearing radiograph taken preoperatively and post operatively. MATERIALS AND METHODS: In our hospital total knee arthroplasty is being done for various indications. This includes varus as well as valgus knees. The period of study is from June 2004 and August 2006. During the study period 18 knees were replaced in12 patients. Of them two patients with three knees lost follow-up. All patients who underwent total knee arthroplasty in our hospital during the period of June 2004 to August 2006 with regular follow-up are included in this study. This includes 10 patients with 15 knees. The patients who did not turn for follow-up were excluded from the study. This included two patients with three knees. RESULTS: The age of the patients who underwent total knee replacement in our series ranged from 42 to 76 years; average was 58.53 years. The standard deviation was 9.7823 and 53% of our patient belonged to the sixth decade. The range in our series was from 150cms to 165cms. The mean was 155.86cms and the SD was 4.9503. The range was from 48kgs to 80kgs. The average weight was 58.73kgs and the SD was 8.2415. CONCLUSION: The level of awareness among the public about the disease process, its natural course and the available treatment modalities including replacement surgery should be brought up. Valgus angle must be assessed in individual patients by taking full length radiographs pre-operatively to get axial alignment corrected. Post-operative study of mechanical axis in full length weight bearing x-ray is a must to assess the restoration of mechanical axis back to normal. Knee scores and functional scores have improved significantly in those groups of patients where there was restoration of mechanical axis. In the rest where the mechanical axis had not been restored the scores have not improved significantly

Life with arthroplasty:The <i>k</i>need for an integrative approach

This thesis focuses on knee arthroplasty surgery. After the introduction, the chapters 2-4 focus on (improving) the technical aspects of knee arthroplasty, while the subsequent chapters 5-9 focus on the results of these procedures for patients and society. The thesis then ends with chapter 10, the general discussion. Chapter 1 provides the General Introduction. Chapter 2 describes the development of a 3D CT based imaging technique to measure the transfer accuracy of a virtually planned osteotomy. In Chapter 3 predicted osteotomy planes are evaluated on accuracy when using patientspecific instrumentation (PSI) for total knee arthroplasty. In Chapter 4 we describe a new and now patented method for diagnosing loosening, a complication of Total Knee Arthroplasty (TKP), using CT and inducible displacement. In Chapter 5 our predominant patient group and location is described. It reports on the results of the hospitals in which our studies are performed as well as the survival for the used TKP is given and risk factors for revision. In Chapter 6 a new questionnaire is developed, the Work, Osteoarthritis and jointReplacement Questionnaire (WORQ). The reliability, validity and responsiveness are tested and reported. Chapter 7 reports on the results of a cross-sectional multicentre survey on return to work following TKP. Chapter 8 looks into differences in return to work between TKP and the less invasive Unicompartmental Knee Arthroplasty (UKP). In Chapter 9 it is assessed which patients do not return to work after TKP. Chapter 10 provides the General discussion