Total knee arthroplasty in France: Male-driven rise in procedures in 2009-2019 and projections for 2050

The impact of implant design consistency in staged bilateral total knee arthroplasty on gait patterns and functional outcomes: A comparative analysis

BACKGROUND

The aim of this study was to assess whether there are any differences in plantar pressure distribution and gait cycle between patients with the same implant design and patients with different designs in staged bilateral TKA and to examine the impact of these differences on clinical and functional outcomes.

METHODS

A retrospective review was conducted of all patients who underwent staged bilateral TKA. The patients were divided into two groups based on the prosthesis design used in both knees. A comparison was made between the two groups regarding various factors, including demographic data, radiological measurements, functional scores, gait analysis, and plantar pressure mapping.

RESULTS

Patients with the same implant design were found to have statistically significantly higher functional scores (p = 0.001). Furthermore, the difference in pre-swing phase plantar distribution for both extremities in patients with different implant designs was found to be greater than in those with the same implant design (p = 0.031). Similarly, the difference in initial contact phase load distribution between the different implant design groups was found to be significantly higher than that observed in the same implant design group (p = 0.014).

CONCLUSION

In conclusion, individuals with two different implant designs in staged bilateral TKA showed a substantial imbalance in gait cycle and plantar pressure distribution. This may result in various consequences, including impairment in movement, patient dissatisfaction, and even early implant failure. Therefore, the same implant design should be used as much as possible to achieve balanced knee kinematics and favorable outcomes.

Cost of Carbon in the Total Cost of a Healthcare Procedure: Example of Micro-Costing Study in a French Setting

BACKGROUND

Economic evaluation aims to compare the costs and results of health strategies to inform public decision making. Although sometimes suggested, until now no national evaluation agency has recommended formally incorporating the cost of greenhouse gas (GHG) emissions generated by health interventions into the estimation of healthcare costs.

OBJECTIVE

The objective of this study was to test and discuss the feasibility of estimating and including the contribution of GHG emissions cost to the total cost of a surgical intervention, with the example of robot-assisted total knee arthroplasty (RTA), using a micro-costing approach.

METHODS

The study was conducted in June 2022 at the William Morey Hospital (France). Data regarding all of the resources (labor, medical equipment, consumables), as well as energy consumption, staff commuting and waste treatment were collected and valued from the hospital point of view. Greenhouse gas emissions were valued using a cost-effectiveness approach. Several sensitivity analyses were performed.

RESULTS

The mean cost per patient of an RTA was estimated to be €4755.65, of which €152.64 (3.21 %) would be attributable to GHG emissions. The contribution of GHG emissions in the overall cost of a health intervention was highly dependent on the convention used for the price of carbon.

CONCLUSION

Despite persistent theoretical and practical challenges, adding the estimation of GHG emission costs in the economic evaluation of health interventions may provide institutional decision makers with information that allows them to allocate the public healthcare resources more efficiently.

Risk prediction of kalaemia disturbance and acute kidney injury after total knee arthroplasty: use of a machine learning algorithm

INTRODUCTION

Total knee arthroplasty (TKA) is a procedure associated with risks of electrolyte and kidney function disorders, which are rare but can lead to serious complications if not correctly identified. A routine check-up is very often carried out to assess the seric ionogram and kidney function after TKA, that rarely requires clinical intervention in the event of a disturbance. The aim of this study was to identify perioperative variables that would lead to the creation of a machine learning model predicting the risk of kalaemia disorders and/or acute kidney injury after total knee arthroplasty.

HYPOTHESIS

A predictive model could be constructed to estimate the risk of kalaemia disorders and/or acute kidney injury after total knee arthroplasty.

MATERIAL AND METHODS

This single-centre retrospective study included 774 total knee arthroplasties (TKA) operated on between January 2020 and March 2023. Twenty-five preoperative variables were incorporated into the machine learning model and filtered by a first algorithm. The most predictive variables selected were used to construct a second algorithm to define the overall risk model for postoperative kalaemia and/or acute kidney injury (K+ A). Two groups were formed of K+ A and non-K+ A patients after TKA. A univariate analysis was performed and the performance of the machine learning model was assessed by the area under the curve representing the sensitivity of the model as a function of 1 - specificity.

RESULTS

Of the 774 patients included who had undergone TKA surgery, 46 patients (5.9%) had a postoperative kalaemia disorder requiring correction and 13 patients (1.7%) had acute kidney injury, of whom 5 patients (0.6%) received vascular filling. Eight variables were included in the machine learning predictive model, including body mass index, age, presence of diabetes, operative time, lowest mean arterial pressure, Charlson score, smoking and preoperative glomerular filtration rate. Overall performance was good with an area under the curve of 0.979 [CI95% 0.938-1.02], sensitivity was 90.3% [CI95% 86.2-94.4] and specificity 89.7% [CI95% 85.5-93.8]. The tool developed to assess the risk of impaired kalaemia and/or acute kidney injury after TKA is available on https://arthrorisk.com.

CONCLUSION

The risk of kalaemia disturbance and postoperative acute kidney injury after total knee arthroplasty could be predicted by a model that identifies low-risk and high-risk patients based on eight pre- and intraoperative variables. This machine learning tool is available on a web platform accessible for everyone, easy to use and has a high predictive performance. The aim of the model was to better identify and anticipate the complications of dyskalaemia and postoperative acute kidney injury in high-risk patients. Further prospective multicentre series are needed to assess the value of a systematic postoperative biochemical work-up in the absence of risk predicted by the model.

LEVEL OF EVIDENCE

IV; retrospective study of case series.

Change in lower limb length following total knee arthroplasty

BACKGROUND

Length variations of the lower limbs after total knee arthroplasty (TKA) constitute a poorly evaluated parameter and can be associated with worse functional outcomes. The objectives of this study were to: (1) describe the variations in the lower limb length after TKA according to the digital accuracy of the computerized navigation system used for prosthesis implantation, (2) describe patient sensation of limb length modification at 3 months postoperatively and to identify its risk factors, (3) identify factors affecting lower limb length modification and to analyze the predictive value causing in the patient the sensation of lower limb discrepancy.

HYPOTHESIS

We hypothesize that there may be a lower limb length discrepancy after TKA, which may cause some distress to the patient.

PATIENTS AND METHODS

This prospective study included 100 TKAs implanted with navigation gap-balanced adjusted mechanical alignment. Were compared the length of the lower limb before and after implantation and the patient's changes in leg length perception at 3 months postoperatively. A subgroup analysis was performed according to preoperative knee deformities: varus knee was an HKA < 177 °, normal knee was an HKA between 117° and 183 ° and valgus was an HKA >183 °.

RESULTS

Ninety-seven out of 100 patients experienced lengthening compared to the preoperative ipsilateral length, and twenty-three experienced lengthening greater than 10 mm. The mean lengthening was 7.3 mm (maximum 24.8 mm). Lengthening was significantly greater in valgus knees 9.9 mm [range, 2.0-24.8] than in varus 7.2 mm [range, 1.46-19.4] and normal knees 4.11 mm [range, 0.4-11.4] (p < 0.05). The correction of frontal and sagittal deformation were risk factors for limb length modification (OR = 0.595; 95% CI [0.544-0.816] [p = 0.001], OR = 0.396; 95% CI [0.351-0.653] [p = 0.001]). Twenty-two patients reported a sensation of limb length change: 11 (50%) reported equalization, whereas the remainder reported lengthening with a leg length difference. The preoperative sensation of lower limb length inequality was the unique factor affecting the patient's perception post-surgery (OR = 37.50; 95% CI [9.730-144.526] [p = 0.0001]). A threshold value of 6.6 mm was identified for the sensation of limb length modification.

CONCLUSION

Navigation is a tool for describing ipsilateral leg length variations after TKA. These variations are significant and perhaps explain some patient dissatisfaction. A partial correction of the frontal deformity according to the knee phenotype could limit the risk of modification of the native length.

LEVEL OF EVIDENCE

IV; Descriptive therapeutic prospective study.

Does the use of topical vancomycin during primary hip or knee arthroplasty protect from infections?

BACKGROUND

Infection is one of the main complications of hip and knee arthroplasties. Topical application vancomycin to prevent postoperative infections is efficient in spine surgery, and is spreading in prosthetic surgery. However, its clinical relevance and safety are still under debate. Thus, we conducted the present study to (1) assess whether topical vancomycin reduces peri-prosthetic infection rate, and (2) investigate its influence on surgical wound complications.

HYPOTHESIS

Our hypothesis was that topical administration of diluted vancomycin during arthroplasty would reduce infection rate within the first postoperative year.

MATERIAL AND METHODS

In total, 1900 hip and knee arthroplasties were performed between 2014 and 2021 in a single hospital. From July 2018 and December 2021, 910 prostheses were implanted with intra-articular instillation of vancomycin and tranexamic acid. From November 2014 to June 2018, 990 prostheses were set up without vancomycin. During a follow-up of minimum 12 months, we reported periprosthetic infections occurring during the first postoperative year, as well as vancomycin-induced general or cutaneous complications.

RESULTS

We observed periprosthetic infections in 9/990 cases (0.91%) of the control group and 10/910 cases (1.1%) of the vancomycin group (p = 0.82). In parallel, we observed wound complications (erythema, seroma, hematoma, dehiscence and delay in wound healing) in 19/990 (1.9%) and 10/910 cases (1.1%) of the control and vancomycin group, respectively (p = 0.19). There were no general complications resulting from the application of vancomycin.

DISCUSSION

Topical diluted vancomycin does not reduce periprosthetic infection risk, and has no effect on the occurrence of surgery wound complications. Considering the present findings, the use of vancomycin cannot be recommended in current practice to prevent infections following hip and knee arthroplasties. Finally, its use does not induce any specific complications, whether local (cicatrisation) or general (related to ototoxicity or nephrotoxicity).

LEVEL OF EVIDENCE

III; case control study.

Prediction of transfusion risk after total knee arthroplasty: use of a machine learning algorithm

INTRODUCTION

Total knee arthroplasty (TKA) carries a significant hemorrhagic risk, with a non-negligible rate of postoperative transfusions. The blood-sparing strategy has evolved to reduce blood loss after TKA by identifying the patient's risk factors preoperatively. In practice, a blood count is often performed postoperatively but rarely altering the patient's subsequent management. This study aimed to identify the preoperative variables associated with hemorrhagic risk, enabling the creation of a machine-learning model predictive of transfusion risk after total knee arthroplasty and the need for a complete blood count.

HYPOTHESIS

Based on preoperative data, a powerful machine learning predictive model can be constructed to estimate the risk of transfusion after total knee arthroplasty.

MATERIAL AND METHODS

This retrospective single-centre study included 774 total knee arthroplasties (TKA) operated between January 2020 and March 2023. Twenty-five preoperative variables were integrated into the machine learning model and filtered by a recursive feature elimination algorithm. The most predictive variables were selected and used to construct a gradient-boosting machine algorithm to define the overall postoperative transfusion risk model. Two groups were formed of patients transfused and not transfused after TKA. Odds ratios were determined, and the area under the curve evaluated the model's performance.

RESULTS

Of the 774 TKA surgery patients, 100 were transfused postoperatively (12.9%). The machine learning predictive model included five variables: age, body mass index, tranexamic acid administration, preoperative hemoglobin level, and platelet count. The overall performance was good with an area under the curve of 0.97 [95% CI 0.921-1], sensitivity of 94.4% [95% CI 91.2-97.6], and specificity of 85.4% [95% CI 80.6-90.2]. The tool developed to assess the risk of blood transfusion after TKA is available at https://arthrorisk.com.

CONCLUSION

The risk of postoperative transfusion after total knee arthroplasty can be predicted by a model that identifies patients at low, moderate, or high risk based on five preoperative variables. This machine learning tool is available on a web platform that is accessible to all, easy to use, and has a high prediction performance. The model aims to limit the need for routine check-ups, depending on the risk presented by the patient.

LEVEL OF EVIDENCE

II; diagnostic study.

Return to work after primary total knee replacement in patients under 55 years of age: a retrospective study of 129 cases

INTRODUCTION

Primary total knee arthroplasty (TKA) has shown excellent results in the treatment of osteoarthritis, and its indications have now been extended to younger patients of working age. Few articles in the literature have studied the return to work of young subjects, and no specific studies have been conducted in France. Therefore, we carried out a retrospective study to 1) investigate the rate and delay of return to work after primary TKA in a population under 55 years of age and 2) identify factors influencing early return to work before 3 months, the period usually used as the duration of initial work stoppage (TS).

HYPOTHESIS

The hypothesis of this study was that the rate and time to return to work were similar to those of other Western studies.

MATERIALS AND METHODS

This was a single-center retrospective study including all patients under 55 years of age who underwent primary TKA between 2010 and 2019, regardless of their professional status. A questionnaire collected all socioeconomic and medical information, time to return to work, and factors influencing it. Our population consisted of 223 TKAs (201 patients), with a participation rate of 64%. Among 129 patients, with a mean age of 50.3 ± 4.6 years [29-55], 109 were working (84%).

RESULTS

Ninety-four of 109 patients (86.2%) returned to work after surgery at a mean time of 17.3 ± 10.6 weeks [12-24]. Previous hip or knee prosthetic surgery had a significant negative influence on the rate of return to work (OR 0.08; 95% CI [0.008; 0.7] [p = 0.027]). Manual workers returned to work significantly earlier (OR 8.2; 95% CI [1.6; 51.4] [p = 0.017]). A total of 56 patients (43.4%) were off work preoperatively, for a mean time of 16.7 ± 17.8 weeks [4,13-24], and 49 of these patients returned to work (87.5%) at a mean time of 18.7 ± 11 weeks [12-24] compared with patients who did not receive a preoperative work stoppage (WK) (p = 0.7).

CONCLUSION

The hypothesis was only partially confirmed. Compared with patients in other Western countries, French patients under 55 years of age who underwent primary TKA surgery appeared to return to work at the same rate but with a longer delay. Patients on WT prior to surgery were more likely to return to work after the operation, although this difference did not reach the significance threshold.

LEVEL OF EVIDENCE IV

Retrospective observational study.

Unicompartmental knee arthroplasty implant survival in patients with borderline indications

INTRODUCTION

In the literature, 80%-92% of patients are satisfied with their medial femorotibial unicompartmental knee arthroplasties (UKAs). These results are associated with a 10-year implant survival rates ranging from 94% to 98% in various studies. Such outcomes are generally reported after excluding patients with obesity, chronic anterior instability, frontal deformities, or preoperative knee flexion deformities exceeding 10 °. These contraindications remain controversial in the literature. The primary objective of this study was to compare the survival rates of implants used for medial femorotibial UKA performed under borderline indications with those of procedures performed under conventional indications and to identify the prognostic factors for revision surgery.

HYPOTHESIS

We hypothesized that the survival of medial femorotibial UKAs is not impacted by these contraindications.

MATERIALS AND METHODS

This was a retrospective, single-center, observational, epidemiological study. All consenting patients who underwent medial femorotibial UKA between 2009 and 2015 were included. Patients who underwent other types of arthroplasties concurrently were excluded. The primary evaluation criterion was implant survival, which was characterized by no need for revision surgery. The borderline indications were defined as follows: obesity (Body Mass index BMI > 30), anterior cruciate ligament (ACL) deficiency, preoperative lower limb frontal deviation ≥10 °, or preoperative flexion deformity ≥10 °.

RESULTS

A total of 468 patients were included, and the average follow-up duration was 8.5 years [7.1; 10.3]. Among them, 270 (57.7%) underwent UKA under at least one borderline indication, whereas 198 (42.3%) underwent UKA under conventional indications. Forty revision surgeries were recorded, and the average time to revision surgery was 26 months. No statistically significant difference in survival was observed between patients with borderline indications and those with conventional indications. Multivariate analysis revealed that obesity (HR = 3.0 [1.5-5.7]) and ACL deficiency (HR = 3.5 [1.4-8.8]) significantly increased the risk of revision surgery.

DISCUSSION

This study revealed no significant difference in survival between UKAs performed under borderline versus conventional indications. Larger studies are needed to confirm these findings.

LEVEL OF EVIDENCE

IV; retrospective observational study. Mots clés: genou, arthroplastie, obésité, ostéoarthrite, survie.

Effectiveness of adductor canal block combined with posterior capsular infiltration on pain and return to walking after total knee arthroplasty: comparative analysis with femoral and popliteal sciatic nerves blocks

INTRODUCTION

Perioperative analgesia after total knee arthroplasty (TKA) reduces morphine consumption and speeds up rehabilitation. The primary objective of this study was to compare the pain experienced by patients with an adductor canal and posterior capsule block with those with a continuous femoral nerve block combined with a popliteal sciatic nerve block. The secondary objectives were to analyze the time to recovery from early walking, length of hospital stay, and block-related complications between the two groups.

HYPOTHESIS

Patients with an adductor canal block and posterior capsular infiltration had less pain 24 h after TKA.

MATERIAL AND METHODS

This single-center retrospective study included 774 TKA between January 2020 and March 2023. Two types of locoregional blocks were evaluated: patients who had a continuous femoral nerve block with a single-shot popliteal sciatic nerve block (FN-PSN group) operated on before March 2022 and those who had a single-shot adductor canal block combined with posterior capsular infiltration (ACB-PI group) operated on after March 2022. One patient in the ACB-PI group was matched to two patients in the NF-BS group according to sex, age, and BMI. A total of 725 TKA were included: 500 in the FN-PSN group and 225 in the ACB-PI group. The primary endpoint was pain assessed using the numerical pain rating scale (NPRS) and opioid consumption at 24 h after TKA. Resumption of walking, defined as getting up for the first time and walking ten steps until discharge from the hospital, and complications between the two groups were also assessed. The study population consisted of 471 women (64.9%) with a mean age of 72.2 ± 8.2 years and a mean BMI of 28.2 ± 4.6.

RESULTS

Patients in the FN-PSN group had less pain at NPRS (1.3 versus 1.9; p < 0.001), and fewer patients required morphine titration (13.8% versus 6.8%, p = 0.02) within the first 8 h of surgery with no difference at 24 h, 48 h and 72 h. The mean doses of morphine administered were similar between the groups. Resumption of walking was significantly longer in the FN-PSN group (1.5 versus 2.0 days, p = 0.003), and hospitalization times and complications were similar between the groups.

CONCLUSION

Adductor canal block combined with posterior capsular infiltration did not reduce postoperative pain compared with femoral and popliteal sciatic block at 24 h after TKA. Opioid consumption and pain were similar between the groups, with more patients requiring morphine in the first eight hours in the ACB-PI group but with a faster return to walking.

LEVEL OF EVIDENCE

III; comparative study.

Comparative performance analysis of Synovasure™ and Leukocyte Esterase assays for the diagnosis of periprosthetic infections in complex microbiological situations

INTRODUCTION

Osteoarticular infections (OAI) after prosthetic surgery have serious functional and economic consequences. Rapid tests for alpha-defensin (TAD) and leukocyte esterase (TLE) are two intra-articular markers involved in the diagnosis of OAIs. TLE cannot be applied in the presence of blood unless centrifugation is used, but the rate of "non-application" of the test for this reason is unknown in complex microbiological situations (discordant or negative puncture, ongoing antibiotic treatment). We therefore conducted a prospective study to determine: 1) the performance of the TAD and TLE rapid tests in diagnosing complex OAI, 2) the rate of non-application of the TLE due to hemarthrosis, and 3) the concordance between the two tests.

ASSUMPTION

These two diagnostic tests had a negative predictive value (NPV) ≥ 90% for the diagnosis of complex OAI.

MATERIALS AND METHODS

A total of 79 suspected OAI patients with complex microbiological diagnoses were included between 2018 and 2023. They were 52 men (66%) for 27 women (34%), with a mean age of 66 ± 13.5 years. The hip (n = 41, 52%) and knee (n = 36, 46%) were the most represented, followed by the elbow (n = 1, 1%) and shoulder (n = 1, 1%). These patients were suspected of having an OAI that required joint puncture, but with a complex microbiological diagnosis due to discordant punctures (n = 21, 27%) or sterile punctures despite strong suspicion of infection (n = 50, 63%), or in case of ongoing antibiotic treatment (n = 8, 10%). All patients underwent joint fluid puncture followed by TAD (Synovasure™, Zimmer, Warsaw, IN, USA) and, when the macroscopic appearance of the sample allowed (clear fluid group), TLE (Multistix 8SG, Siemens Healthcare GmbH, Erlangen, Germany). The results of both tests were compared with Musculoskeletal Infection Society (MSIS) criteria.

RESULTS

Of the 79 patients included, 27 (34%) were considered infected according to the MSIS. In 30% of cases (n = 24), TLE was not feasible due to the presence of blood in the joint fluid. In the "clear fluid" group, the NPV was equal to 90% for both TAD (sensitivity 87%, specificity 88%) and TLE (sensitivity 87%, specificity 81%). The two parameters showed almost perfect agreement (κ = 0.927).

CONCLUSION

TAD and TLE are two rapid, reliable tests with near-perfect concordance and high NPV, even in situations of complex microbiological diagnosis. They are particularly useful for deciding on a therapeutic strategy for patients with complex OAI. The TLE cannot be used in 30% of cases due to hemarthrosis, but centrifugation can correct this defect.

LEVEL OF EVIDENCE

III; Prospective comparative diagnostic accuracy study.

Effectiveness of Telerehabilitation Programs in Elderly with Hip or Knee Arthroplasty: A Systematic Review

Background: Lower limb osteoarthritis (OA) often generates musculoskeletal pain causing functional impairment and decreasing mobility, autonomy, and quality of life. Patients with OA are commonly prescribed specific care for total hip arthroplasty or total knee arthroplasty (THA or TKA), when patients present symptoms that are refractory to nondrug treatments. Currently, when patients are discharged from orthopedic surgery, they are either referred to a rehabilitation department, or sent directly home with assistance such as remote monitoring by teleconsultation or a mobile application. In recent years, there has been an evolution in digital health and in particular telerehabilitation. To determine utility and effectiveness, the aim of this systematic review was to highlight and evaluate different telerehabilitation programs using new information and communication technologies. Methods: Five databases, ScienceDirect, PubMed, Web of Sciences, Scopus, and Google scholar, were searched until 30 June 30, 2023. All studies written in English and meeting our inclusion criteria were included. Databases were screened for "Total Hip Arthroplasty," "Total Knee Arthroplasty," "Total Hip Replacement," "Total Knee Replacement," "Rehabilitation," "Physical Activity," "Physiotherapy," "Telerehabilitation," "Telecommunication*," "Senior*," and "Elderly" in accordance with PRISMA-ScR guideline. Results: Fourteen articles were selected according to inclusion criteria. Telerehabilitation was offered in seven different ways (video call, applications smartphones, website, etc.). Assessments included were mainly quality of life questionnaires, perceived effort after exercises, field surveys on the tool experience, and physical tests to assess motor functions. Conclusion: This review highlights the importance and relevance of evaluating the contributions and limits of new health technologies to improve patient monitoring and thus enable better remote clinical care.

Long-term results (after a mean 11.3years, and up to 22years, of follow-up) of the Legacy Constrained Condylar Knee (LCCK™) in primary total knee arthroplasty

INTRODUCTION

The use of a sliding prosthesis in total knee arthroplasty (TKA) with increased stress is an intermediate solution in primary surgery, between posteriorly stabilized prostheses and hinged prostheses, in cases of ligamentous laxity and/or loss of bone substance. Favorable results have been reported in the medium term but to our knowledge, this type of prosthesis has not been evaluated in Europe beyond 10 years of follow-up. We therefore conducted a retrospective study in order to carry out: 1) the study of the survival of the Legacy Constrained Condylar Knee (LCCK™) prosthesis in primary surgery, 2) the analysis of complications, functional scores and radiographic data, 3) the analysis of the link between the diaphyseal filling rate and prosthetic loosening.

HYPOTHESIS

The LCCK™ sliding prosthesis with increased constraint has equivalent long-term survival and clinical results to standard posteriorly stabilized TKA and superior to hinged TKA.

MATERIAL AND METHOD

A retrospective series of 141 LCCK™ implanted in 134 patients between 1997 and 2010 was analyzed. Survival was assessed with censoring through an evaluation of partial or total revision of the implants. The functional results were evaluated using the IKS and Oxford 12 scores. Data regarding the Canal Fill Ratio (CFR) and the presence of pathological periprosthetic lines were also collected.

RESULTS

The average follow-up was 11.3±5.3years with a maximum follow-up of 22.7years. Survival at 20years was 90.8% [95% CI: 83.7-95.7]. The rate of early complications was 13.5% (19/141), predominantly comprised of venous thrombosis (6/141), hematomas (3/141 including two requiring surgical drainage), stiffness (3/141) and early infections (3/141). The rate of late complications was 17% (24/141), led by stiffness (4.4%; 6/141), infections (2.9%; 4/141) and hardware failure (2. 2%; 3/141). Ten of the 141 patients (7.1%) had LCCK failure, including 3 (2.1%) for stiffness, 3 (2.1%) for hardware failure, 2 (1.4%) for infection, 1 (0.7%) for laxity and 1 (0.7%) for a periprosthetic fracture. No aseptic loosening was found. The total IKS score went from 65 [0-116] to 143 [79-200] at follow-up, the IKS knee score went from 30 [0-66] to 85 [44-100], and the IKS function score went from 35 [0-70] to 57 [0-100]. The Oxford score went from 14 [2-25] to 34 [15-48] at follow-up. Only two patients (1.4%) presented with a partial periprosthetic line. The tibial CFR was 0.81 and the femoral CFR was 0.76. The influence of the CFR could not be analyzed due to the absence of loosening.

DISCUSSION

The LCCK™ prosthesis in primary surgery has good medium-term survival, a significant improvement in functional scores and a complication rate comparable to posteriorly stabilized prostheses. The complication rate is lower than that of hinged prostheses.

LEVEL OF EVIDENCE

IV; single-center retrospective study.

Effects of amino acid supplementation on muscle mass, muscle performance and functional capacity in subjects undergoing total knee arthroplasty: a systematic review of randomized clinical trials

The aim of the present study was to summarize the effectiveness of amino acid supplementation on muscle strength, muscle volume, and functional capacity in patients undergoing total knee arthroplasty. For this, in November 2022, a search was carried out in the PubMed, Cochrane Library, and EMBASE databases, identifying a total of 2182 documents, of which only 4 were included in the present review. The included studies had 148 participants (47 men and 101 women), with a minimum age of 53 and a maximum of 92 years, and supplementation times of 13 to 30 days (1 to 3 times a day). For the results, in relation to muscle performance, when comparing the control and experimental groups, greater muscle atrophy was observed in the pre- and post-moments of the control group, in relation to the experimental group. In addition, studies suggest a good tendency for muscle mass gain, and improvement in the functional capacities of patients who used supplementation. Therefore, the use of amino acids after TKA surgery reduces muscle atrophy, which preserves muscle mass and leads to better performance in tests of strength and functional capacity, when compared to the use of a placebo.

Long-term results of a rotationally unconstrained fixed-bearing total knee prosthesis

PURPOSE

Introduced in the market in 1990 by Ceraver (France), the posterior-stabilised (PS) Hermes prosthesis has limited literature regarding long-term survivability. The purpose of the study is to evaluate the survival and functional outcomes of the prosthesis.

METHODS

A retrospective case series was performed including 164 patients (176 knees) having undergone total knee arthroplasty with the Hermes prosthesis between 1997 and 2000 with a follow-up period of 18 years.

RESULTS

Kaplan-Meier analysis showed a survival rate of 99.4% (95% CI. 96.0-100.0%) at 18.4 years with one revision. At final follow-up, the International Knee Society (IKS) functional score was 93.2 ± 15.6 and IKS knee score was 99.1 ± 2.5.

CONCLUSION

The Hermes PS model is a low conformity prosthesis that offers reliable durability that is comparable to other popular designs while minimizing rotational constraints and having an approachable learning curve for new users.

Which method for femoral component sizing when performing kinematic alignment TKA? An in silico study

INTRODUCTION

The kinematically alignment (KA) technique for TKA aims to reproduce the pre-arthritic knee anatomy, including both the femoro-tibial and femoro-patellar joints. An in silico study was conducted to compare 3 different femoral component sizing techniques to identify the anatomical landmark which allows closest restoration of the native trochlear anatomy. Our study's question was: what was the best method for sizing the femoral component when performing KA-TKA? It was hypothesized that sizing the femoral component by aiming to restore the groove height would be the best method to restore the native trochlear anatomy.

METHODS

GMK sphere® (Medacta) femoral component 3D models were virtually kinematically aligned on 30 tri-dimensional (3D) bony osteoarthritis knee models. The femoral component was mediolaterally positioned to match distal native and prosthetic grooves. Three methods were used to size the femoral component: a conventional method with the anterior femoral cut flush to the femoral cortex (C-KATKA) and two alternative personalized methods aiming to recreate either the medial facet's height (ATM-KATKA) or the groove's height (ATG-KATKA). In-house analysis software was used to compare native and prosthetic trochlear articular surfaces and mediolateral implant overhangs.

RESULTS

Compared with the C-KATKA, ATG-KATKA and ATM-KATKA techniques increased the component size by a mean of 0.90 (SD 0.31, min 0.5 to max 1.5) (p<0.001) and 1.02 (SD 0.31, min 0.5 to max 1.5) (p<0.001), respectively. C-KATKA technique substantially proximally understuffed the trochleae with maximum values of 7.11mm (SD 1.39, min 3.93mm to max 10.57mm) in the medial facet, 4.72mm (SD 1.27, min 1.46mm to max 6.86mm) in the lateral facet and 4.51mm (SD 1.40, min 1.92mm to max 7.30mm) in the groove, respectively. Alternative techniques understuffed medial facet with maximum values of 5.07mm (SD 1.29, min 2.83mm to max 8.34mm) and 4.70mm (SD 1.52, min 0.83mm to max 8.04mm) for ATG-KATKA and ATM-KATKA techniques, respectively. There was no significant understuffing of the groove or lateral facet for alternative techniques (ATM and ATG). The ATM-KATKA and ATG-KATKA techniques generated mediolateral implant overhang, mainly postero-lateral, with a rate of 90.0% and 86.7%, respectively. In this study, no mediolateral implant overhang was found for C-KATKA.

DISCUSSION/CONCLUSION

The C-KATKA technique substantially understuffs the native trochlear articular surfaces in medial, lateral and groove parts. Alternative techniques (ATM-KATKA and ATG-KATKA) for sizing the femoral component better restore the native trochlear anatomy but also generate a high rate of postero-lateral implant overhangs. Would this postero-lateral implant overhang be clinically deleterious remains unknown? The aspect ratio of contemporary femoral TKA implants can probably be optimized to allow a better anatomical restoration of the anterior femoral compartment.

LEVEL OF EVIDENCE

II, in silico study.

Design, Simulations and Tests of a Novel Force and Moments Sensor for Instrumented Knee Implants

OBJECTIVES

Early identification of mechanical complications of total knee arthroplasties is of great importance to minimize the complexity and iatrogenicity of revision surgeries. There is therefore a critical need to use smart knee implants during intra or postoperative phases. Nevertheless, these devices are absent from commercialized orthopaedic implants, mainly due to their manufacturing complexity. We report the design, simulations and tests of a force and moments sensor integrated inside the tibial tray of a knee implant.

METHODS

By means of a "tray-pillar-membrane" arrangement, strain gauges and metal additive technology, our device facilitates the manufacturing and assembly steps of the complete system. We used finite element simulations to optimize the sensor and we compared the simulation results to mechanical measurements performed on a real instrumented tibial tray.

RESULTS

With a low power acquisition electronics, the measurements corroborate with simulations for low vertical input forces. Additionally, we performed ISO fatigue testings and high force measurements, with a good agreement compared to simulations but high non-linearities for positions far from the tray centre. In order to estimate the center of pressure coordinates and the normal force applied on the tray, we also implemented a small-size artificial neural network.

CONCLUSION

This work shows that relevant mechanical components acting on a tibial tray of a knee implant can be measured in an easy to assemble, leak-proof and mechanically robust design while offering relevant data usable by clinicians during the surgical or rehabilitation procedures.

SIGNIFICANCE

This work contributes to increase the technological readiness of smart orthopaedic implants.

Predicting whether patients will achieve minimal clinically important differences following hip or knee arthroplasty

Aims

A substantial fraction of patients undergoing knee arthroplasty (KA) or hip arthroplasty (HA) do not achieve an improvement as high as the minimal clinically important difference (MCID), i.e. do not achieve a meaningful improvement. Using three patient-reported outcome measures (PROMs), our aim was: 1) to assess machine learning (ML), the simple pre-surgery PROM score, and logistic-regression (LR)-derived performance in their prediction of whether patients undergoing HA or KA achieve an improvement as high or higher than a calculated MCID; and 2) to test whether ML is able to outperform LR or pre-surgery PROM scores in predictive performance.

Methods

MCIDs were derived using the change difference method in a sample of 1,843 HA and 1,546 KA patients. An artificial neural network, a gradient boosting machine, least absolute shrinkage and selection operator (LASSO) regression, ridge regression, elastic net, random forest, LR, and pre-surgery PROM scores were applied to predict MCID for the following PROMs: EuroQol five-dimension, five-level questionnaire (EQ-5D-5L), EQ visual analogue scale (EQ-VAS), Hip disability and Osteoarthritis Outcome Score-Physical Function Short-form (HOOS-PS), and Knee injury and Osteoarthritis Outcome Score-Physical Function Short-form (KOOS-PS).

Results

Predictive performance of the best models per outcome ranged from 0.71 for HOOS-PS to 0.84 for EQ-VAS (HA sample). ML statistically significantly outperformed LR and pre-surgery PROM scores in two out of six cases.

Conclusion

MCIDs can be predicted with reasonable performance. ML was able to outperform traditional methods, although only in a minority of cases.

Unicompartmental knee arthroplasty: A French multicenteric retrospective descriptive study from 2009 to 2019 with projections to 2050

INTRODUCTION

Unicompartmental knee arthroplasty (UKA) is a reliable and reproducible procedure. While some surgeons have incorporated it into their therapeutic armamentarium, others do not use it routinely, leading to a large disparity in practice. The objective of this study was to investigate in France the epidemiology of UKA from 2009 to 2019 to identify: (1) the evolution of growth trends by sex and age, (2) the evolution of the state of comorbidity of patients during the operation, (3) the evolution of trends according to the regions, (4) the projection best suited to the observations at 2050.

HYPOTHESIS

Our hypothesis was that in France, an increase would be observed over the period studied, differing according to the characteristics of the population.

MATERIALS AND METHOD

The study was conducted in France over the 2009-2019 period for each gender and age group. The data was taken from the NHDS (National Health Data System) database, which includes all the procedures carried out in France. Based on the collection of procedures performed, the incidence rates (per 100,000 inhabitants) and their evolution were deduced, as well as the indirect assessment of the patient's comorbidity status. Using linear, Poisson, and logistic projection models, incidence rates were projected to the years 2030, 2040, and 2050.

RESULTS

Between 2009 and 2019, the incidence rate of UKA increased sharply (from 12.76 to 19.57; +53%), the growth was different in men (from 10.78 to 20.34; +89%) and women (from 14.61 to 18.85; +29%). The male/female sex ratio increased from 0.69 in 2009 to 1.0 in 2019. The increase was greatest among men under 65 (from 4.9 to 9.9; +100%) and lowest among women over 75 (from 41.2 to 40.5; -2%). Over the period studied, the proportion of patients with mild comorbidities (HPG1) increased (from 71.7% to 81.1%) at the expense of the other classes with more severe comorbidities. This dynamic was observed for all age groups: 0-64 years (from 83.3% to 90%), 65-74 years (from 81.4% to 88.4%), 75 years and over (38 .2% to 52.6%) regardless of sex. There was a strong disparity between the regions with a change in the incidence rate ranging from -22% (from 29.8 to 23.1) for Corsica to +251% (from 13.9 to 48.7) for Brittany. The proposed projection models suggested an increase in the incidence rate of +18% in logistic regression, +103% in linear regression by 2050.

DISCUSSION

Our study showed strong growth in the number of UKAs in France over the period studied, being highest in young men. The proportion of patients with fewer comorbidities increased for all age groups. A disparity in inter-regional practice was identified, with indications that remain ambiguous and differ according to the practitioner. We can expect continued growth in the years to come, adding to the care burden.

LEVEL OF EVIDENCE

IV; Descriptive epidemiological study.