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Osteopetrosis is a rare metabolic bone disease, characterized by dysfunction of osteoclasts, resulting in increased bone density and brittleness leading to pathological fractures and bone deformities. Hip and knee osteoarthritis (OA) are common long-term complications in patients with osteopetrosis. Joint arthroplasty surgery remains an effective and recommended treatment for these patients with an end-stage OA because it provides favorable outcomes. However, in osteopetrosis, joint arthroplasty surgery carries an increased risk of complications, and specific preoperative and perioperative considerations are required to deal with the technical challenges related to the disease. The aim of this article was to review some of the key aspects of osteopetrosis, provide technical recommendations, and answer clinically relevant questions related to hip and knee arthroplasty surgery., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Orthopaedic Surgeons.)

Purpose: While restricted kinematic alignment (rKA) total knee arthroplasty (TKA) with cemented implants has been shown to provide a similar survivorship rate to mechanical alignment (MA) in the short term, no studies have reported on the long-term survivorship and function., Methods: One hundred four consecutive cemented cruciate retaining TKAs implanted using computer navigation and following the rKA principles proposed by Vendittoli were reviewed at a minimum of 10 years after surgery. Implant revisions, reoperations and clinical outcomes were assessed using knee injury and osteoarthritis outcome score (KOOS), forgotten joint score (FJS), patients' satisfaction and joint perception questionnaires. Radiographs were analyzed to identify signs of osteolysis and implant loosening., Results: Implant survivorship was 99.0% at a mean follow-up of 11.3 years (range: 10.3-12.9) with one early revision for instability. Patients perceived their TKA as natural or artificial without limitation in 50.0% of cases, and 95.3% were satisfied or very satisfied with their TKA. The mean FJS was 67.6 (range: 0-100). The mean KOOS were as follows: pain 84.7 (range: 38-100), symptoms 85.5 (range: 46-100), function in daily activities 82.6 (range: 40-100), function in sport and recreation 35.2 (range: 0-100) and quality of life 79.1 (range: 0-100). No radiological evidence of implant aseptic loosening or osteolysis was identified., Conclusion: Cemented TKA implanted with the rKA alignment protocol demonstrated excellent long-term implant survivorship and is a safe alternative to MA to improve patient function and satisfaction., Level of Evidence: IV, continuous case series with no comparison group., (© 2024 The Author(s). Knee Surgery, Sports Traumatology, Arthroscopy published by John Wiley & Sons Ltd on behalf of European Society of Sports Traumatology, Knee Surgery and Arthroscopy.)

Background: Total knee arthroplasty (TKA) is considered the gold standard treatment for patients who have advanced hemophilic knee arthropathy. However, special considerations are required for these patients. This prospective study reports on the need for soft-tissue procedures, implant types, complication rates, mean 53.3 months implant survivorship, and patient-reported outcome measures of TKA in hemophilic patients., Methods: There were twenty primary TKAs that were performed on 15 hemophilic patients from 2012 to 2023. The mean follow-up was 53.3 months (range, 6 to 128). The necessity for additional soft tissue procedures, implant type, complications, and revision rates were recorded. Knee Injury and Osteoarthritis Outcome Score, Knee Society Score, Hemophilia-specific Quality of Life Questionnaire for Adults, Hemophilia Activities List, and range of motion, were compared preoperatively and at the last follow-up., Results: At the last follow-up, implant survivorship was 90%. There were 2 revisions: one for aseptic loosening and one for periprosthetic joint infection. Additional soft tissue procedures included 2 quadriceps snips (10%). Tibial augments, tibial stubby stems, and both tibial and femoral traditional stems were used in one (5%), 4 (20%), and one (5%) TKAs, respectively. A constrained posterior-stabilized bearing was necessary in one case. Clinically and statistically significant improvements were found between the preoperative and final follow-up values of all patient-reported outcome measures, knee flexion (73 versus 108 °, P < 0.001), and flexion contracture (11 versus 4 °, P = 0.002)., Conclusions: This study showed that TKA, in patients who have hemophilic knee arthropathy, is a reliable treatment option that improves knee function and patients' quality of life with acceptable implant survival rates at midterm follow-up (mean 53.3 months). Standard implants and approaches can be used in most cases. Despite good outcomes, hemophilic patients carry additional risks for complications that require specific considerations. It is paramount for these patients to be treated in specialized centers by experienced surgeons to achieve good results., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Over the years, with a better understanding of knee anatomy and biomechanics, superior implant designs, advanced surgical techniques, and the availability of precision tools such as robotics and navigation, a more personalized approach to total knee arthroplasty (TKA) has emerged. In the presence of extra-articular deformities, performing personalized TKA can be more challenging and specific considerations are required, since one has to deal with an acquired pathological anatomy. Performing personalized TKA surgery in patients with extra-articular deformities, the surgeon can: (1) resurface the joint, omitting the extra-articular deformity; (2) partially compensate the extra-articular deformity with intra-articular correction (hybrid technique), or (3) correct the extra-articular deformity combined with a joint resurfacing TKA (single stage or two-stage procedure). Omitting the acquired lower limb malalignment by resurfacing the knee has the advantages of respecting the joint surface anatomy and preserving soft tissue laxities. On the other hand, it maintains pathological joint load and lower limb kinematics with potentially detrimental outcomes. The hybrid technique can be performed in most cases. It circumvents complications associated with osteotomies and brings lower limb axes closer to native alignment. On the other hand, it creates some intra-articular imbalances, which may require soft tissue releases and/or constrained implants. Correcting the extra-articular deformity (through an osteotomy) in conjunction with joint resurfacing TKA represents the only true kinematic alignment technique, as it aims to reproduce native knee laxity and overall lower limb axis.

Background: This study reports the minimum 10 years results of total hip arthroplasty (THA) performed using a monoblock acetabular component with a large-diameter head ceramic-on-ceramic bearing., Methods: Of the 276 THAs included in this study, there were eleven deaths and 27 patients lost to follow up (11%) during the follow-up, leaving 237 (85%) hips available for review at a mean of 10.5 years (range, 10 to 12) postoperatively. Reoperations, implant revisions, adverse events, clinical outcomes, radiographic evaluation, and whole blood metal ion levels were assessed at the last follow-up., Results: After a minimum of 10 years, implant survivorship was 98.7%. There were 3 revisions (1.3%): one for insufficient acetabular cup primary fixation, one traumatic periprosthetic acetabular fracture, and one probable deep chronic infection. No dislocation or ceramic implant fracture was observed. The mean University of California at Los Angeles activity score, Western Ontario and McMaster Universities Osteoarthritis Index score, and Forgotten Joint Score were 5.6 (2 to 10), 90.1 (9 to 100), and 79.2 (4 to 100), respectively. All patients (100%) were satisfied or very satisfied. Since implantation, 43% of patients reported hearing a squeaking noise from the prosthesis. But all patients who reported squeaking were satisfied with the surgery. The mean titanium level was 2.2 μg/L (1.1 to 5.6). No progressive radiolucent lines, osteolysis, or implant loosening signs were observed at the last radiographic evaluation., Conclusions: A large-diameter head ceramic-on-ceramic THA provides outstanding long-term (minimum 10 years) implant survivorship with unrestricted activity while avoiding implant impingement, liner fracture, and hip instability. Functional outcomes, satisfaction, and joint perception were excellent. Although the incidence of squeaking was high, it did not affect patient satisfaction or function. The systemic titanium levels were low, related to unavoidable passive corrosion of implant surfaces, and did not reveal any indirect signs of trunnionosis., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Advanced hemophilic knee arthropathy is a frequent and devastating manifestation of severe hemophilia with significant implications for activities of daily living. Hemophilic arthropathy is caused by repeated bleeding, resulting in joint degeneration, pain, deformity and disability. In patients with hemophilia and advanced disease, total knee arthroplasty (TKA) has proven to be the most successful intervention, improves physical function and reduces knee pain. Hemophilic patients carry additional risks for complications and required specific pre/postoperative considerations. Expert treatment center should be used to improve patient outcome. Hemophilic patients present significant surgical challenges such as joint destruction, bone loss, severe ankylosis and oligoarticular involvement. The surgeon performing the arthroplasty must be experienced to manage such problems.

Background: Complex anatomy of the proximal femur makes total hip arthroplasty (THA) more challenging. Short, straight, fluted and conical titanium stem like the Wagner Cone can be helpful to address small femoral canal, increased femoral neck version, important leg length discrepancy or proximal femoral deformity. The outcome in these patients is less assured and associated with high rate of complications. Therefore, we did a retrospective study aiming to answer: 1) can the Wagner Cone stem provide acceptable mid- to long-term implant survivorship; 2) help minimizing perioperative adverse events; 3) produce favorable clinical outcome measured by WOMAC score; and 4) be associated with a favorable radiographic femoral bone remodeling at the last follow-up?, Hypothesis: Wagner Cone stem is an advantageous solution for the distorted proximal femur in complex THA., Patients and Method: Our cohort was derived from the patient registries where medical records of 88 patients (103 hips) who underwent primary THA using the Wagner prosthesis were retrospectively reviewed. Then, data was analyzed for patients' demographics and surgical data, and comparing preoperative, immediate postoperative and last follow-up data. Eleven patients (12 hips) were excluded (7 hips followed up less than 2 years or lost to follow-up, 3 hips that had the Wagner stem for revision and 2 Wagner stems inserted for periprosthetic fracture). This left 77 patients (91 hips) with Wagner cone stems implanted for more than 2 years between March 2003 and February 2017 by 7 surgeons in 3 academic hospitals. Implant revision, reoperations, WOMAC score and radiographic analyses were recorded at last follow-up., Results: After a mean follow-up of 7.8 (range, 2.0-16.2) years, Wagner stem survivorship was 98.9% (95% CI: 94 to 100%) with one (1.1%) stem revision for failure of osteointegration. Five (5.5%) acetabular revisions, one for aseptic loosening, 2 for adverse reaction to metal debris and 2 for infection. One (1.1%) sciatic neuropathy and 4 (4.4%) intraoperative fractures were encountered. The mean WOMAC score was 90.5±11.4 (59-100). Radiographic analysis showed clear signs of stem osseointegration and hypertrophic bone remodeling in 82 cases (92.1%)., Conclusions: Used in complex cases with proximal distorted femurs, the Wagner Cone stem demonstrated a low complication rate, a high-rate consistent adaptive bone remodeling, excellent clinical results, and midterm survival. It is a safe, reliable and advantageous option in complex primary THA. However, the contribution of the underlying cause of the secondary osteoarthritis on the long-term survival of the stem remains to be demonstrated., Level of Evidence: IV; retrospective study., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

Total knee arthroplasty (TKA) procedures are expected to increase up to 565% in the United States over the next 3 decades. TKAs were traditionally performed with neutral mechanical alignments that provided equal medial and lateral gaps in extension and flexion to reduce implant wear but were less successful at restoring native knee function and associated with high patient dissatisfaction. Kinematic alignment (KA) restores native anatomy and minimizes soft tissue release; however, KAs that recreate severe deformities and/or biomechanically inferior alignments result in significant increases in implant stress and risk of aseptic loosening. Restricted kinematic alignment (rKA) recreates pre-arthritic anatomy within a range of acceptable alignment boundaries, and improved patient clinical scores and faster recoveries have been reported with rKA techniques. Personalized Alignment™ is an evolution of rKA that relies heavily upon robotic assistance to reliably recreate patient anatomy, native soft tissue laxity, and accurate component placement to improve patients' clinical outcomes. The purpose of this surgical technique report is to describe the Personalized Alignment TKA method using the ROSA ® Knee System and Persona ® The Personalized Knee ® implants. Herein we provide specific procedures for pre-operative planning, anatomical landmarking and evaluation, intra-operative planning and adjustment of resections and cuts, cut validation and soft tissue evaluation with robotic-assisted personalized TKA., Competing Interests: VM is a paid consultant for ZB. VM receive Royalties for ROSA knee product., (© 2023 Massé, Cholewa and Shahin.)

Case: We present a severe hemophilia A patient with high titers of inhibitors presenting stage IV knee arthropathy with functional bilateral arthrodesis. On presentation, his mode of ambulation was to project himself forward without the benefit of any significant ankle motion. Total knee arthroplasty was performed on both knees and allowed significant improvement in the range of motion of both knees from 5° to 100°., Conclusion: Although hemophilic patients with inhibitors can represent complex cases, successful outcomes can be achieved in a multidisciplinary team setting. However, we would recommend performing this type of surgery at an earlier stage when less extensive muscle and tendon release is required., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSCC/B803)., (Copyright © 2022 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Ceramic-on-ceramic (CoC) bearings for total hip arthroplasty (THA) have been offering very favorable results and survivorship since their introduction. In order to increase range of movement (ROM) and decrease dislocation rates, some manufacturers have introduced larger diameter head (LDH) CoC bearings. This has been achieved with the use of preassembled cup designs, in which the ceramic liner is already fitted into the metal backing and implanted as a monoblock component by the surgeon. In this report we present data from a series of 5 patients with ceramic liner dissociation from a monoblock cup., Case Presentation: All cases were overweight men with acetabular components of 56 or 58 mm. After a mean of 5.5 (range, 3.5-6.7) years, all patients reported sudden pain and audible noise when performing activities of daily living. Liner displacement was suspected on plain radiographs and confirmed by Ct-scan. Pneumarthrosis was present in all cases. Taper modular junction wear and corrosion signs were observed in the four revised patients., Conclusion: Although one of our case is still treated conservatively, implant revision is probably inevitable. Further LDH CoC implant design should take in consideration this potential complication by avoiding bearing diameters over 40mm and/or improving locking mechanism or by providing a real monoblock acetabular implant., (© 2022. The Author(s).)

X-Atlas™ is a new imaging technology intended to advance the state of the art in patient-specific instrumentation. It uses standard AP and lateral radiographs instead of CT or MRI scans to create 3D bone models, which can be used to perform pre-operative surgical planning and fabricate TKA personalized guides. The aim of this study was to validate X-Atlas™ and evaluate the accuracy of personalized guides created with this imaging technology. Its ability to predict implant size was also determined. The accuracy of the X-Atlas™ imaging technology was evaluated by comparing the landmarks of X-Atlas™ 3D Bone models to MRI-reconstructed bone models. The accuracy of PSI guides created with X-Atlas™ (X-PSI™ guides) was evaluated during a validation study (16 specimen knees) and a clinical study (50 patients; Health Canada #CSU2015-12K). Optical navigation was used to measure positioning accuracy. In addition, the ability of X-Atlas™ to predict implant size was assessed. The accuracy of the X-Atlas™ imaging technology was below 0.87 and 1.28 mm for the femoral and tibial landmarks, respectively. The accuracy of X-PSI™ guides to reproduce the pre-operative planned HKA was within ± 3° in 100% and 86.1% of cases, for the laboratory and clinical study respectively, which was significantly better than historical data for conventional instrumentation. X-Atlas™ was able to predict implant size to ± 1 size in 95.6% and 100%, for the femur and tibia component respectively. The X-Atlas™ imaging technology demonstrated excellent accuracy for reconstructing a 3D bone model. The results show that PSI guides created with X-Atlas™ (X-PSI™ guides) provide greater implant positioning accuracy than conventional instrumentation, without the requirement of advanced imaging. Furthermore, the X-Atlas™ imaging technology could effectively predict implant sizing, potentially reducing the number of instrument trays and improving surgical efficiency.

Background: Trunnionosis of large diameter (LDH) metal-on-metal total hip arthroplasty (THA) was linked to high systemic chromium (Cr) and cobalt (Co) ion levels and local adverse reactions to metal debris (ARMD). The safety of CoC LDH THA is not yet available at mid-term. Measuring whole blood Ti level of ceramic on ceramic (CoC) LDH THA with a titanium (Ti) stem is an indirect way to assess the performance of its head-neck taper modular junction. Therefore, we wanted to determine: (1) if the whole blood Ti ion levels in patients with LDH CoC THA after a minimum of 5 years of implantation is within the expected values for similar well performing Ti THA, (2) if Ti level scientifically increases over time, which would suggest the presence of a progressive modular head/neck junction wear process, (3) if clinical or radiographical manifestations of implant dysfunction are present?, Hypothesis: Ti blood levels of LDH CoC THA will indirectly reflect the expected levels due to passive corrosion of the implants and will be stable over time., Patients and Methods: We report the whole blood Ti, Cr, and Co levels at 5years minimum for 57 patients with unilateral primary LDH CoC THA with head sizes ranging from 36 to 48mm using Ti stem and acetabular component. To compare Ti ion levels modification over time, in 25 patients were a previous measurement (1-3years) was available, we compared it to their last follow-up results (>5 years). Mean Ti level in well performing Ti THAs is recognized to be around 2.0 ug/L. Although, there are no universally accepted Ti levels associated with problematic implant, we used safety threshold of 10 ug/L. Clinical and radiological outcomes were recorded at last follow-up., Results: At 79 months mean follow-up, all mean Ti levels were 1.9μg/L (min 1.2, max 4.4) and all subject had values below the safety threshold of 10ug/L. In the subgroup of 25 cases with a previous measurement, there was a decrease in mean Ti levels between 20 months and 78 months follow-up (2.2μg/L (1.6-3.9) versus 2.0μg/L (1.4-2.8), p=0.007). No statistically significant relation was observed between Ti level at last FU and bearing diameter (rho=0.046, p=0.0734) or the presence or absence of a Ti adaptor sleeve (p=0.454): 1.94ug/L (min 1.20, max 2.80) versus 1.90ug/L (min 1.20, max 4.40). At last follow up, no patients presented osteolysis signs on radiographs, clinical signs of ARMD or were reoperated. Most patients had excellent clinical with 98% of them reporting minor (29%) or no functional limitation (69%) and 44% perceive their THA as a natural hip joint. However, 3/57patients (5%) temporarily experienced hip squeaking and 18/57 (31%) reported clicking sound., Conclusion: With the tested LDH CoC THA, Ti levels were low and related the uneventful and unavoidable passive corrosion of implant surfaces. Mid-term measurement of Ti in subjects with LDH CoC did not reveal any indirect signs of trunnionosis, which should already be observable by this time., Level of Evidence: IV, retrospective study., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Background: Assessing patients' functional outcomes following total knee arthroplasty (TKA) with traditional scoring systems is limited by their ceiling effects. Patient's Joint Perception (PJP) question of the reconstructed joint is also of significant interest. Forgotten Joint Score (FJS) was created as a more discriminating option. The actual score constituting a "forgotten joint" has not yet been defined. The primary objective of this study is to compare the PJP and the FJS in TKA patients to determine the FJS score that corresponds to the patient's perception of a natural joint., Methods: One hundred TKAs were assessed at a mean of 40.6 months of follow-up using the PJP question, FJS, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Correlation between the 3 scores and their ceiling effects were analyzed., Results: With PJP question, 39% of the patients perceived a natural joint (FJS: 92.9; 95% confidence interval [CI], 89.4-96.4), 12% an artificial joint with no restriction (FJS: 79.5; 95% CI, 65.7-93.3), 36% an artificial joint with minor restrictions (FJS: 70.0; 95% CI, 63.2-76.9), and 13% had major restrictions (FJS: 47.3; 95% CI. 32.8-61.7). PJP has a high correlation with FJS and WOMAC (Spearman's rho, -0.705 and -0.680, respectively). FJS and WOMAC had a significant ceiling effect with both reaching the best possible score in >15%., Conclusion: Patients perceiving their TKA as a natural knee based on PJP have a FJS ≥89. PJP has a good correlation with FJS and may be a shorter, simple, and acceptable alternative., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Introduction: An attractive option to reduce hospital length of stay (LOS) after hip or knee joint replacement (THA, TKA) is to follow the Enhanced Recovery After Surgery principles (ERAS) to improve patient experience to a level where they will feel confident to leave for home earlier. The objective of this study was to evaluate the implementation of short-stay protocol following the ERAS principles., Hypothesis: We hypothesized that our ERAS THA and TKA short-stay protocol would result in a lower complication rate, shorter hospital LOS and reduced direct health care costs compared to our standard procedure., Material and Methods: We compared the complications rated according to Clavien-Dindo scale, hospital LOS and costs of the episode of care between a prospective cohort of 120 ERAS short-stay THA or TKA and a matched historical control group of 150 THA or TKA., Results: Significantly lower rate of Grade 1 and 2 complications in the ERAS short-stay group compared with the standard group (mean 0.8 vs 3.0, p<0.001). No difference was found between the 2 groups for Grade 3, 4, or 5 complications. The mean hospital LOS for the ERAS short-stay group decreased by 2.8 days for the THAs (0.1 vs 2.9 days, p<0.001) and 3.9 days for the TKAs (1.0 vs 4.9 days, p<0.001). The mean estimated direct health care costs reduction with the ERAS short-stay protocol was 1489 CAD per THA and 4158 CAD per TKA., Discussion: In many short-stay protocols, focus has shifted from ERAS goals of a reduction in complications and improved recuperation to use length of stay as the main factor of success. Implementation of an ERAS short-stay protocol for patients undergoing THA or TKA at our institution resulted not only in reduced hospital LOS, but also in improved patient care and reduced direct health care costs., Level of Evidence: Level II., (Copyright © 2019 The Author(s). Published by Elsevier Masson SAS.. All rights reserved.)

Introduction: In total hip arthroplasty (THA), local adverse reaction to metal debris (ARMD) may be caused by abnormal metal ion release from a metal-on-metal (MoM) bearing, or by wear and corrosion of the implant's modular junction. The aim of this study was to compare ion levels and rate of ARMD between patients sharing the same MoM bearing but 1 group having monoblock stems versus another having modular stems., Materials and Methods: Whole blood cobalt (Co) and chromium (Cr) ion concentrations, ARMD rate, revision rate, and function measured by UCLA and WOMAC scores were compared between groups., Results: ARMD rate was significantly higher in the modular group (46%) compared with the monoblock group (16%, p = 0.031). Revision for ARMD was performed at 52.8 ± 8.1 months in the modular group versus 98.2 ± 15.5 months after primary THA in the monoblock group. ARMD originated from wear and corrosion of the junction between stem and femoral head adapter sleeve in all monoblock cases, and the junction between stem and modular neck in all the modular ones. Cr and Co ions levels were significantly higher in the modular stem group ( p < 0.001 for both)., Conclusions: Although both groups had MoM bearings, corrosion at stem/neck or neck/head junctions combining dissimilar metal (Ti and Cr-Co) was seen as the source of excess metal ions release leading to ARMD. Poor performance of the modular junction may be more deleterious than wear of the bearing. To avoid such complications, THA femoral stem modular junctions should be eliminated (return to a full monoblock implant) or have improved junction design.

Introduction: Metal ion release from wear and corrosion at the femoral head-stem taper junction can evoke local adverse reactions to metal debris (ARMD). In a specific large-diameter head (LDH) total hip arthroplasty (THA) system, ceramic femoral heads of 44 to 48 mm are available with a titanium (Ti) adaptor sleeve, while heads of 36- to 40-mm come without sleeves. The hypothesis of this study is that the Ti adaptor sleeve with LDH ceramic-on-ceramic (CoC) bearings will not cause wear or corrosion at the taper junction and, thus, will not generate high whole blood Ti ion levels., Methods: We compared whole blood Ti levels at minimum 1-year follow-up in 27 patients with unilateral primary LDH CoC THA with head sizes ranging from 36 to 48 mm using a Ti stem and acetabular component., Results: Although Ti ion levels in patients with 36- to 40-mm head diameters without Ti sleeve were found to be statistically significantly higher (2.3 μg/l: 1.6-3.1, SD 0.44) compared to those with a Ti sleeve (1.9 μg/l: 1.6-2.2, SD 0.19) (p = 0.020), the found difference has no clinical importance. No patients presented clinical signs of ARMD, and the clinical results in both groups were similar., Conclusions: LDH CoC THA Ti levels were low and probably related to unavoidable passive corrosion of implant surfaces. Measurement of Ti in subjects with ceramic LDH, with or without Ti adaptor sleeve, did not disclose undirected signs of trunnionosis.

Background: In recent decades, the popularity of modular necks in total hip arthroplasty (THA) has increased since modular necks offer the potential to restore the patient's native anatomy, and thus improve stability. Unfortunately, modular necks are associated with higher complication rates, including implant fracture and modular junction corrosion with adverse local tissue reaction to metal debris., Objective: The objective of this study was to determine the impact of modular neck material on titanium (Ti), chrome (Cr), and cobalt (Co) metal ion levels in patients who underwent a THA with Ti femoral stem, Ti or CrCo modular neck, and ceramic-on-ceramic (CoC) bearing., Methods: Whole blood Ti, Cr, and Co levels were compared at a minimum 1-year follow-up in 36 patients who underwent unilateral, primary CoC large-diameter head THA with Profemur ® Preserve modular femoral stems (MicroPort, Arlington, TX, USA)., Results: Higher Co concentrations were observed in the CrCo modular neck group (0.46 versus 0.26 µg/l in the Ti neck group, P=0.004) and higher Ti concentrations were observed in the Ti modular neck group (1.98 vs 1.59 µg/l in the CrCo neck group, P=0.007). However, these differences were not clinically meaningful since the absolute values remained within what is considered the safe range of Ti, Cr, and Co ions in whole blood. No patients were re-operated or revised., Conclusion: Modular neck materials had an impact on whole blood metal ion levels but the concentrations measured remained within the safe range at 1-year follow-up. There were no indirect signs of modular junction corrosion with either CrCo or Ti femoral necks.

Purpose: Kinematic total knee arthroplasty (TKA) is an emerging technique, but concerns remain around the effect of implanting the prosthesis in more anatomic orientations. Native knees show variation in joint line orientation relative to the tibial mechanical axis but the joint line remains parallel to the floor when standing. This study was undertaken to evaluate joint line obliquity relative to the floor when weight-bearing after kinematic TKA to see if a similar effect occurs., Methods: Preoperative and postoperative measurements were taken for 55 consecutive kinematically aligned TKAs, including the joint line orientation angle (JLOA), formed between the joint line and a line parallel to the floor., Results: The mean medial proximal tibial angle (MPTA) was 3.4° varus pre-operatively (1.7° valgus to 7.9° varus, SD 2.0), and 3.0° varus postoperatively (5.5° valgus to 6.5° varus, SD 2.1). The mean postoperative JLOA was 1.0° varus with a smaller range than the MPTA (2.6° valgus to 6° varus, SD 1.9). The difference between these two measurements was significant (mean 2°, SD 2.5, p < 0.001)., Conclusions: Relative to the mechanical axis, 33 tibial components would be considered at risk outliers, being orientated at more than 3° in varus or valgus. However, only six components were outside this range relative to the vertical, all in varus (mean 4.2°). This latter measurement may better represent how the prosthesis is functionally loaded and is similar to mechanically aligned TKAs with good survivorship. This may help explain why kinematic alignment does not lead to higher earlier failure rates that may result if similar orientations were seen with mechanically aligned TKA.

Osteoarthritis of the knee is associated with deformities of the lower limb. Tibia valga is a contributing factor to lower limb alignment in valgus knees. We evaluated 97 valgus knees and 100 varus knees. Long-leg films were taken in weight bearing with both knees in full extension. For valgus knees, 52 knees (53%) had a tibia valga deformity. Average tibia valgus deformation was 5.0°. For varus knees, there was only 1 case of tibia valga (1%), with a deformation of 2.5°. The aim of this study was to assess the prevalence of primary tibia valga in valgus and varus knees and understand how it affects our approach to total knee arthroplasty (TKA). We recommend having full-leg length films when planning for TKA in valgus knees., (Copyright © 2014 Elsevier Inc. All rights reserved.)

The pivot shift test is the only clinical test which correlates with knee function following rupture of the ACL. A grade is given to the pivot shift in a subjective manner, leading to efforts to quantify the bone movements and correlate them to the grade. However, the dynamic and unconstrained nature of the manoeuvre introduces important kinematic variability. Our main objective was to develop a method to lessen the variability attributable to clinician technique, therefore increasing inter-grade differences. Three different orthopaedic surgeons each performed the pivot shift test on 12 subjects. Knee joint kinematics were recorded using electromagnetic motion capture devices. Inter-clinician variability was quantified and a method was developed to diminish it, using the angular velocity of flexion. This method was then applied to a larger population composed of 127 knees with various degrees of instability, evaluated by one of eight different orthopaedic surgeons. The clinical grades given by the clinicians were in almost perfect agreement (kappa=0.83). Normalization of kinematic parameters using the angular velocity of knee joint flexion produced by the clinicians reduced the intra-clinician variability by 20%, resulting in an intra-class correlation coefficient (ICC) of 0.52, up from 0.41 before normalization. This allowed for more significant differences between the grades of pivot shift. Simple normalisation of pivot shift kinematics using the angular velocity of flexion reduces clinician-related variability and allows for significant differences between the different grades. These results are an important step towards developing an objective measurement tool for the pivot shift phenomenon., (Copyright © 2010 Elsevier B.V. All rights reserved.)