The effect of obesity on mechanical failure after total knee arthroplasty

'Increased aseptic tibial failures in patients with a BMI e35 and well-aligned total knee arthroplasties'published in The Journal of Arthroplasty on July 2, 2015 draws the conclusion that the risk of revision total kneearthroplasties (TKA) due to aseptic tibial component loosening is two times greater in patients with a BMIe35 kg/m2, independent of age or limb alignment. This result confirms that obese patients are at a higher risk ofmechanical complications after performing TKA, independently from the risk of infection. This study suggeststhat the management of obese patients for TKA must be meticulous, careful, and should inspire from great bonedeformations in valgus of varus when choosing implants

Similar survival rate but lower functional outcomes following TKA in the elderly people compared to younger patients: analysis of a posterior stabilised implant with minimum 5-year follow-up

BACKGROUND: Literature regarding outcomes in patients over 80years old after total knee arthroplasty (TKA) is inconsistent. We aimed to compare implant survivorship and functional outcomes between elderly patients (??80years) and younger patients (?0.05), nor regarding maximum flexion (121°?±?12 and 117°?±?13, p?=?0.08). The implant survivorship was 100.0% after a mean 64.4-month follow-up (range 60-78), without revision requiring removal of the implant in any group. The survival rate without any reoperation was 97.6% (95% CI 93.0-100.0) in the elderly group and 95.9% (95% CI 92.5-99.5) in the younger group (p?=?0.64).CONCLUSION: At a minimum of 5-year follow-up, there was no revision surgery and a very low rate of complications requiring reoperations both in the group over 80years of age and in the younger population, with the use of a PS prosthesis. The functional results were slightly lower for elderly patients and correlate with the lower functional demands of this population. The indication for TKA, especially with a PS implant, may be encouraged in appropriately selected elderly patients.LEVEL OF EVIDENCE: III (retrospective cohort study)

No clinical difference at mid-term follow-up between TiN-coated versus uncoated cemented mobile-bearing total knee arthroplasty: a matched cohort study

Introduction: Nitride-based ceramic coating was introduced into surgical implants to improve hardness, reduce abrasion, and decrease the risk of metal-induced adverse reactions, especially for patients with suspected or identified metal hypersensitivity. The study aimed to evaluate the effectiveness and safety of a titanium nitride (TiN) coated prosthesis with a mobile bearing design. Methods: This was a retrospective matched-cohort study from a single center, comparing clinical outcomes between patients receiving either a TiN-coated versus an uncoated cobalt-chromium-molybdenum (CoCrMo) prostheses for primary total knee replacement. Seventeen patients received the TiN prosthesis between 2015 and 2019. These were matched 1:2 with patients receiving uncoated mobile-bearing knee prostheses with the same design manufacturer. Results: Fourteen patients in the TiN group had complete 5-year follow-up data and were compared with 34 patients from the CoCrMo group. The Knee Society Score was 170.6 ± 28.0 (Function subscore 83.7 ± 17.5 and Knee subscore 86.9 ± 13.8) in the TiN group and 180.7 ± 49.4 (Function subscore 87.5 ± 14.3 and Knee subscore 93.2 ± 9.6) in CoCrMo group, with no statistically significant difference (p = 0.19). One patient underwent a revision for instability requiring the removal of the implant in the TiN group and none in the CoCrMo group. The survival rates were 92.9% (CI95% 77.3–100.0) and 100.0% in the TiN group and CoCrMo group respectively (p = 1.0). Discussion: TiN-coated TKA with mobile bearing resulted in satisfactory clinical outcomes, and a low revision rate, and there was no complication related to the coated implant. The use of TiN-coated prostheses in case of confirmed or suspected metal allergy provides satisfactory short-term clinic outcomes

Equivalent results of medial and lateral parapatellar approach for total knee arthroplasty in mild valgus deformities

PURPOSE: When performing total knee arthroplasty (TKA) in valgus knee deformities, a medial or lateral parapatellar approach can be performed, but the lateral approach is often considered technically more difficult. The purpose of this study was to compare intra-operative, early clinical and radiological outcomes of medial and lateral parapatellar approaches for TKA in the setting of moderate knee valgus

How long does image based robotic total knee arthroplasty take during the learning phase? Analysis of the key steps from the first fifty cases

INTRODUCTION: Robotically assisted total knee arthroplasty (RA-TKA) is an emerging surgical tool. The purpose of this study was to analyze the length of time taken to perform the key steps of a RA-TKA for a surgeon and centre new to the MAKO robotic system. METHOD: This was a prospective cohort study of the first 50 patients undergoing TKA using a robotic platform (Mako, Stryker, Kalamazoo, MI, USA) performed by a single surgeon. Each key surgical step was recorded. The first 50 patients were chronologically allocated into five groups of ten and compared.RESULTS: Mean operation length was 59.4?±?7.4min with significant improvement after 30 cases. A significant effect on certain steps of the surgery also occurred over 50 cases: after 30 cases for pre-operative planning (3.8min in group 1 versus 1.2min in group 4, p

Correction to: Kinematic alignment fails to achieve balancing in 50% of varus knees and resects more bone compared to functional alignment

Authors would like to correct the errors in Table2. The original article has been corrected

Kinematic alignment fails to achieve balancing in 50% of varus knees and resects more bone compared to functional alignment

PURPOSE: Evidence is emerging that tibio-femoral compartmental balancing is related to clinical outcomes after total knee arthroplasty (TKA). The purpose of this study was to assess if kinematic alignment (KA) delivered a balanced knee in flexion and extension after TKA on varus deformity, compared to functional alignment (FA). METHODS: This single-centre retrospective cohort study assessed 110 consecutive TKAs performed with an image-based robotic system for pre-operative varus deformity. The ligament balancing in the medial and lateral femorotibial compartments was assessed intra-operatively with a robotic system to evaluate if a KA plan would deliver a balanced knee. Balance was considered achieved if tibio-femoral compartments (medial/lateral) were equal to or less than 1.5mm, or if the estimated final gap position more than 2mm from the global implant thickness (17mm). Implant positioning was modified within limits previously defined for a FA philosophy to achieve balancing. Resection thickness and implant positioning were compared with the KA plan and after the FA adjustments; and also, between the patients with a final balanced knee in extension and at 90° of flexion.RESULTS: A total of 102 patients were eligible for final analysis. Mean age was 67.3?±?8.2years, average BMI was 29.1?±?5.2kg/m2, mean pre-operative coronal alignment was 174.0°?±?3.3° and sagittal alignment 3.4°?±?5.9°. Mean post-operative coronal alignment was 177.7°?±?1.0° and sagittal alignment 0.8°?±?1.9°. A KA plan delivered medial-lateral tibio-femoral compartment balancing in 67 cases (65.7%) for the extension gap and in 50 cases (49.1%) for the flexion gap. All measured bone resection depths were significantly less for FA compared to KA. To achieve balancing targets, final femoral component position was more externally rotated relative to the posterior condylar axis, (0.5° with KA compared to 1.7° with FA (p

Functional Alignment Philosophy in Total Knee Arthroplasty – Rationale and technique for the varus morphotype using a CT based robotic platform and individualized planning

Introduction: Alignment techniques in total knee arthroplasty (TKA) continue to evolve. Functional alignment (FA) is a novel technique that utilizes robotic tools to deliver TKA with the aim of respecting individual anatomical variations. The purpose of this paper is to describe the rationale and technique of FA in the varus morphotype with the use of a robotic platform. Rationale: FA reproduces constitutional knee anatomy within quantifiable target ranges. The principles are founded on a comprehensive assessment and understanding of individual anatomical variations with the aim of delivering personalized TKA. The principles are functional pre-operative planning, reconstitution of native coronal alignment, restoration of dynamic sagittal alignment within 5° of neutral, maintenance of joint-line-obliquity and height, implant sizing to match anatomy and a joint that is balanced in flexion and extension through manipulation of implant positioning rather than soft tissue releases. Technique: An individualized plan is created from pre-operative imaging. Next, a reproducible and quantifiable method of soft tissue laxity assessment is performed in extension and flexion that accounts for individual variation in soft tissue laxity. A dynamic virtual 3D model of the joint and implant position that can be manipulated in all three planes is modified to achieve target gap measurements while maintaining the joint line phenotype and a final limb position within a defined coronal and sagittal range. Conclusion: Functional alignment is a novel knee arthroplasty technique that aims to restore constitutional bony alignment and balance the laxity of the soft tissues by placing and sizing implants in a manner that it respects the variations in individual anatomy. This paper presents the approach for the varus morphotype

Does healing of both greater and lesser tuberosities improve functional outcome after reverse shoulder arthroplasty for fracture? A retrospective study of twenty-eight cases with a computed tomography scan at a minimum of one-year follow-up

PURPOSE: Reverse shoulder arthroplasty (RSA) is often indicated in elderly patients with displaced proximal humerus fractures (PHF). The rate of greater tuberosity (GT) healing varies from 37 to 90% in this population. The aim of this study was to assess greater and lesser tuberosity (LT) fixation and healing on CT scan after RSA for PHF. Our hypothesis was that both GT and LT healing leads to better functional results after RSA for fracture. METHODS: Our retrospective cohort consisted of 28 patients treated with an RSA for a four-part PHF during the inclusion period. The mean age at surgery was 77 years. Clinical examination and CT scan were performed at a minimum one year follow-up to assess tuberosity position and healing. RESULTS: The GT healed in 22 patients (78.5%), the LT in 24 patients (87.5%) and both tuberosities were healed in 20 patients (71.5%). Constant score was significantly improved with GT, LT and both tuberosity healing (p = 0.05, p = 0.04 and p = 0.02 respectively). Motion in anterior elevation was improved with GT and both tuberosity healing (p = 0.01 and p = 0.04 respectively). Motion in external rotation was improved with GT and both tuberosity healing (p = 0.01 and p = 0.02 respectively). CONCLUSION: GT and LT healing was associated with better functional results and active motion. Anatomical reduction and consolidation of both tuberosities is beneficial with a cumulative effect for functional recovery