Comparing the lower limb joint biomechanics of the Power Knee, C-Leg and Rheo Knee during ramp and stair ambulation.

One of the most significant developments in prosthetic knee technology has been the introduction of the Microprocessor-Controlled Prosthetic Knee (MPK). However, there is a lack of consensus over how different types of MPKs affect performance in different ambulation modes. In this study, we investigated the biomechanical differences in ramp and stair maneuvers when an individual with transfemoral amputation wears three commercial MPKs: the Össur Power Knee, the Össur Rheo Knee and the Ottobock C-Leg 4. The primary outcome variable for this study was the lower limb biological joint work, inclusive of the intact leg and prosthetic side hip. We hypothesized that (1) the Power Knee would result in lower biological work during ascent activities than the C-Leg and Rheo, both passive MPKs, and (2) the C-Leg and Rheo would result in lower biological work during descent activities than the Power Knee. During ramp ascent, the C-Leg was associated with lower biological joint work (p < 0.05) than the Power Knee. However, this relationship did not hold during stair ascent, where the Power Knee showed advantages for stair ascent with net reductions in biological joint work of 14.1% and 23.3% compared to the Rheo and C-leg, respectively. There were no significant differences in biological joint work between the knees during ramp and stair descent, indicating that choice of MPK may not be as important for descent activities. Our results demonstrate that differences are present between different types of MPKs during ascent activities which could prove useful in the prescription of these devices.

Is there sufficient evidence to support the use of antibiotic holiday just before the second stage of an infected total hip or knee arthroplasty revision surgery?

The practice of implementing an antibiotic holiday before the second stage of hip or knee arthroplasty is currently controversial due to limited evidence for this approach, as per the International Consensus Meeting 2018 on Musculoskeletal Infection. A greater understanding of this issue could augment the quality of Alrayes and Sukeik's mini-review (2023) on diagnosing, managing, and treating periprosthetic knee infections. However, a significant lack of literature exists concerning the optimal duration for the antibiotic holiday, calling for more research before establishing any clinical guidelines.

Assessing the influence of gastrocnemius reconstruction on stress distribution of femoral tumor rotating hinge knee prosthesis via finite element analysis.

Background: After femoral oncological knee arthroplasty, some patients suffer from rotating axis fracture, which significantly impacts the life span of the rotating hinge knee (RHK) prosthesis. This research aimed to analyze the biomechanical response of anatomical gastrocnemius reconstruction and assess whether it could reduce the risk of rotating axis breakage by finite element (FE) analysis. Methods: A femur-prosthesis-tibia FE model was established using the data from CT scans. The mechanical properties of the RHK implant were quantitatively compared before and after gastrocnemius reconstruction at 6 angles: 10°, 20°, 30°, 40°, 50°, and 60°. Results: Our results showed that gastrocnemius reconstruction effectively altered the stress distribution around the rotating axis, considerably relieving the stress in the fracture-prone region. In addition, the peak stress in the rotating axis, bending axis, prosthesis stem, and femoral condyles decreased variably. Conclusion: In distal femoral resection knee arthroplasty, the rebuilding of gastrocnemius substantially improved the stress distribution within the prosthesis, thereby having the potential to reduce the risk of prosthetic fracture and prolong the overall durability of the prosthesis.

Does backward gait require more proprioception and balance in older adults after total knee arthroplasty?

Objectives: Some basic and instrumental daily living activities include backward gait. There is a need to clarify which parameters should be focused more on to improve backward gait in older individuals. This research investigated the proprioception, and balance in forward-backward gait of older individuals with total knee arthroplasty (TKA). Methods: A prospective cross-sectional research was conducted with 105 older adults with TKA. Individuals' forward and backward gait performance was assessed with the Timed Up & Go Test (TUG) and 3 Meter Walk Back Test (3MBWT), respectively. Proprioception was measured with a mobile application-based inclinometer. Berg Balance Scale (BBS) and Activity Specific Balance Confidence Scale (ABC) were used to assess balance and balance confidence levels, respectively. A single clinician evaluated the individuals. Results: TUG was weakly and positively correlated with the Right and Left Leg Proprioception Test (RLPT and LLPT) (r1 = 0.386, r2 = 0.391, p < 0.01). Also, the 3MBWT was weakly and positively correlated with RLPT and LLPT, respectively (r1 = 0.293, r2 = 0.251, p < 0.01). In addition, TUG was strongly and negatively correlated with BBS and ABC, respectively (r1 = -0,693, r2 = -0.722, p < 0.01). Besides, 3MBWT was strongly and negatively correlated with BBS and ABC (r1 = -0.642, r2 = -0.645, p < 0.01). Conclusion: The study revealed that forward and backward walking were similarly associated with balance and proprioception in older adults with TKA. Clinicians should focus more on balance ability than proprioception to improve backward walking performance in older individuals with THA.

Anatomical Safety Area for Periarticular Analgesic Infiltration through the Posterior Capsule in Total Knee Arthroplasty: Radiological Study in Magnetic Resonance.

Background: One of the main challenges of orthopedic surgery is adequate pain management after total knee arthroplasty. This work aimed to determine the anatomical safety area for infiltration through the posterior capsule of the knee in prosthetic surgery using Magnetic Resonance Imaging (MRI). Methods: A descriptive, observational, cross-sectional study was performed on 126 knee MRIs. The variables studied were age, sex, and distance between different neurovascular structures of the popliteal fossa (tibial nerve, common peroneal nerve, and vascular bundle). Data were analyzed for normality (Kolmogorov-Smirnov) and variance homogeneity (Levène). A value of p < 0.05 and a confidence interval of 9% were considered statistically significant for all comparisons. Student's t-test was used to compare the means between independent samples. Results: We observed statistically significant differences between the sexes regarding EP-EPS (external plateau-external popliteal sciatic nerve (common peroneal)), EP-IPS (external plateau-internal popliteal sciatic nerve (tibial)), and IP-PA (internal plateau-popliteal artery) measurements. The average distance between both nerves, EPS-IPS (external popliteal sciatic nerve and internal popliteal sciatic nerve), was 25.96 mm in females, while the value obtained in males was 29.93 mm, but this difference was not statistically significant. Conclusions: The average distance from the posterior capsule to the EPS and IPS nerves is greater in males than in females, despite no statistical differences. The presence of a lateralized arteriovenous bundle reduces the infiltration area of the external compartment. Regarding the safety area, infiltration of the internal compartment is safe since the volume diffuses into the muscle mass of the internal gastrocnemius upon injection. To infiltrate the external compartment, the needle must move at least 2 cm from the midline toward the external side (to exceed the maximum displacement of the neurovascular bundle established at 1.82 cm), and not advance beyond 0.76 cm (minimum distance at which we located the common peroneal nerve in the external compartment).

Outcomes of rotating versus pure hinge knee arthroplasty in the setting of one-stage exchange for periprosthetic joint infection.

PURPOSE: Rotating or pure hinge knee prostheses are often used in case of periprosthetic joint infection (PJI). Five-year survival data of rotating hinge implants ranging from 52 to 90%, whereas pure hinge data are sparse. This study describes the results of both hinge knee prostheses after one-stage septic exchange. METHODS: One hundred sixty-seven one-stage septic exchanges of a primary unconstrained total knee arthroplasty (TKA) to a cemented hinge prosthesis (117 rotating and 50 pure hinge TKAs) performed between 2008 and 2017 were retrospectively reviewed. Exclusion criteria were stem extensions or augments used in primary TKA, history of extensor mechanism reconstruction, and a follow-up less than two years after surgery. Rates of reinfection, mechanical failures, and all-cause revision-free survival data were documented. RESULTS: At five years, the all-cause revision-free survival was 77% (95% CI 69 to 82). Thirty-one patients (19%) had further revision for aseptic reasons. In the rotating hinge group, the mechanical failure rate was more than twice as high as in the pure hinge group (13% vs 6%), significantly influenced by higher body weight. At a mean follow-up of 6.7 years, 21 (13%) patients had a reinfection and underwent a further surgery. Reinfection rates did not differ between the two groups. CONCLUSION: The use of hinge TKA in the revision of PJI shows favourable five year infection-free and all-cause revision-free survival rates of 91% and 77%, respectively. Our study showed poorer results of the rotating hinge design. These results may help surgeons to choose proper implants in case of septic knee revision.

Use of semi-constrained total knee arthroplasty in gonarthrosis with collateral ligament insufficiency: Clinical and functional outcomes.

INTRODUCTION: Achieving stability in total knee arthroplasty (TKA) is crucial for long-term implant survival. In cases of severe deformity or ligament laxity, constrained implants may be required. Traditionally, increasing constraint involved intramedullary stems. However, there are intermediary alternatives, including employing a constrained polyethylene insert without stems, thereby avoiding complications related to them. The study aims to evaluate our experience with a non-modular constrained (NMC) implant in primary TKA. MATERIAL AND METHODS: We conducted a retrospective review of the clinical and radiographic outcomes of 108 non-stemmed primary TKAs performed at our institution between 2013 and 2021 in patients with at least 10° deformity or 10mm ligament laxity. Data included demographics, preoperative and postoperative deformities, clinical outcomes and revision rates. RESULTS: A total of 103 patients (108 knees) with a mean age of 74 were followed up for a minimum of 2 years. The mean postoperative range of motion was 105°/0°. The median Oxford Knee Score, Knee Society Score and Knee Society Function Score were 43.5, 92 and 90, respectively. 17 knees had varus deformity (mean tibiofemoral angle of 2.7°), and 87 knees had excessive valgus deformity (mean tibiofemoral angle of 15.1°). The remaining 4 knees had a neutral alignment. The mean postoperative tibiofemoral angle was 6.8°. The overall revision rate was 6.5% (7 patients): 3 deep periprosthetic infections, 2 patellar dislocations, 1 stiffness and 1 aseptic loosening. CONCLUSION: Our experience demonstrates favorable mid-term outcomes with the NMC implant, providing a safe alternative to stemmed implants in primary TKA, particularly in cases of severe deformity or ligament laxity.

Influence of patients' preoperative expectations on postoperative outcomes after total knee or hip arthroplasty: a systematic review.

Purpose: The association between preoperative expectations and treatment outcomes in total hip arthroplasty (THA) or total knee arthroplasty (TKA) is still unclear. Therefore the aim is to examine the association between preoperative outcome expectations, process expectations, and self-efficacy, and the postoperative outcomes overall outcome, pain, function, stiffness, satisfaction, and quality of life following THA/TKA. Methods: A systematic review with narrative synthesis was conducted. PubMed, EMBASE, PsycINFO, CINAHL and Cochrane Library were searched from inception to October 17, 2022. Included were prospective longitudinal cohort studies published in English, German, or Dutch, with an adult population undergoing THA/TKA, and including at least one measure of preoperative expectations and the postoperative outcomes mentioned earlier. Two independent reviewers screened the retrieved articles for eligibility, a third solved disagreements. Risk of bias (RoB) was assessed using the QUIPS tool. Results: Of the 50 included studies, 38 had high RoB and 12 moderate RoB. Unadjusted results suggest a positive association between preoperative outcome expectations and overall outcome in the medium and long term, and between self-efficacy and change in 'overall outcome' in the long term. Adjusted results suggest positive associations between outcome expectations and function and between self-efficacy and overall outcome in the medium term, and for outcome expectations with pain and change in pain, respectively, and self-efficacy and stiffness in the long term. Conclusions: Preoperative expectations show a possible positive association with specific outcome measures, such as pain or function. For future research, it is advised to link matching specific expectations with specific outcomes.

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.

Management of periprosthetic femoral fractures following total knee arthroplasties using locking plates or intramedullary nailing. Comparative study of 567 cases.

INTRODUCTION: Proximal femur fractures in elderly patients pose a common problem that requires surgical management. The main objective of this study was to compare the results of treatment by locked plate (LP) and by anterograde (AIN) or retrograde (RIN) intramedullary nailing. The secondary objective was to analyze the complications related to each group. The hypothesis of this study was that the radiological and clinical results of each group were comparable. MATERIALS AND METHODS: The data of 438 patients from 8 centers were studied retrospectively with 365 LP and 69 cases of intramedullary nailing (49 AIN and 20 RIN). The groups were comparable in terms of mean age (75±2years), mean preoperative Parker score (5.3±0.5) and mean KOOS score (74±2). Most patients lived at home before their fracture [n=375 (86%)]. At follow-up, the joint range of motion, the KOOS and Parker scores, living premises, the time required to regain full weight-bearing, the time required for consolidation as well as the reduction alignment: frontal, sagittal, horizontal. RESULTS: The average follow-up was: 79±2weeks (65 to 82). The functional and radiological results were comparable, although nailing allowed a faster return to weight-bearing (1±2weeks for nailing versus 7±2weeks for LP, p=0.048) and a better postoperative Parker score (5.5±0.5 for nailing versus 4.7±0.2 for LP, p=0.045). Rotational malalignment in femoral nailing was often in the direction of internal rotation, compared to the LP (p=0.045). Complications were comparable with the exception of mortality, which was more frequent for LP [22.5% in the LP group versus 13% in the nailing group (p=0.045)]. Complications were categorized as: mechanical complications 6.8% of LP, 5.7% of nailing (p>0.05), infections [11% of LP, 5.8% of nailing (p>0.05)], surgical revisions [2% of LP, 10% of nailing (p>0.05)]. DISCUSSION AND CONCLUSION: The hypothesis was refuted. These results show that nailing conferred a faster recovery of weight-bearing, a better Parker score, and is associated with a lower mortality rate. The morbidity rate is comparable between the two techniques. Indeed, when the indication for osteosynthesis by LP or by nailing is made, and both choices are technically justifiable, it would be prudent to favor the technique, which carries the least risk, which in this case is nailing. This conclusion must, however, be taken in to consideration with regard to the reduced number of nailing. A larger series of nailing, particularly retrograde, would be necessary to be able to confirm this last difference between the 2 groups. LEVEL OF EVIDENCE: IV; comparative retrospective study.

Investigation of Reaction Time, Proprioception, and Shaped Pathway Walking Performance in Older Patients with Total Knee Arthroplasty.

OBJECTIVES: The existing literature on total knee arthroplasty (TKA) does not provide clear data on step reaction time and proprioception and gait in shaped pathways. This study investigated the relationship between proprioception and reaction time with walking performance in shaped pathways in older patients undergoing TKA. DESIGN: A cross-sectional observational study. SETTING AND PARTICIPANTS: An orthopedic outpatient clinic with 103 older patients with TKA after a minimum of 6 months after surgery. METHODS: Participants were evaluated with Figure-of-8 Walk Test (F8WT), L Test, Tinnetti Gait Test (TGT), proprioception measurement with an app-based inclinometer, and step reaction time (SRT) test. The same assessor carried out all evaluations. RESULTS: F8WT showed a strong correlation with SRT-right, SRT-left, and Tinetti Gait Test (TGT), respectively (r1 = 0.628, r2 = 0.619, r3 = -0.615, P < .01). In addition, F8WT was moderately correlated with Right Leg Proprioception Test (RLPT) and Left Leg Proprioception Test (LLPT), respectively (r1 = 0.487, r2 = 0.439, P < .01). There was a moderate correlation between L Test with RLRT, LLRT, and TGT, respectively (r1 = 0.597, r2 = 0.584, r3 = -0.542, P < .01). Besides, there was a weak positive correlation between L Test with RLPT and LLPT, respectively (r1 = 0.394, r2 = 0.335, P < .01). A regression model showed that the L test was related to RLRT, LLRT, and TGT (R2 = 0.432, P < .001). The higher ability of the L test was weakly associated with higher levels of TGT (standardized ß = -0.28, P = .0012). Besides, regression analysis also proved that F8WT was related to RLRT, LLRT, and TGT (R2 = 0.522, P < .001). The most highly associated parameter was LLRT (standardized ß = 0.958, P = .003). CONCLUSIONS AND IMPLICATIONS: Gait in shaped pathways is associated with proprioception, reaction time, and balance ability in older patients with TKA. Therefore, proprioception, reaction time, and balance should be considered to improve the shaped pathway walking performance of patients after bilateral, right, or left TKA surgery.

[Unicompartmental knee prosthesis]. / Prótesis unicompartimental de rodilla.

In a patient with severe unicompartmental knee osteoarthritis where conservative treatments have been exhausted, with painful symptoms located on the affected side and with a reducible axis, the unicompartmental knee prosthesis (UKP) is the first option for our work group. Within the study to confirm the diagnosis and plan the surgery, weight-bearing knee x-rays, Rosenberg x-rays, and teleradiographs of the lower extremities stand out. The objective of surgery is to replace the affected area, restoring the anatomy with an adequate balance of soft tissues. Regarding alignment, the challenge is not to overload the opposite side or that of the prosthesis. There are mobile and fixed plates and although the clinical and survival results are similar, in recent years with the incorporation of robotic surgery, the balance has tipped towards the use of fixed plates. The clinical and functional results are better and there are fewer complications than when total knee prostheses (TKP) are used in the same type of patients. The survival studied in registries is lower than for TKP, but when used in high-flow centers where the percentage of UKP is close to a third of the total with strict patient selection, the duration is as good as in PTR.

En un paciente con artrosis unicompartimental de rodilla grave, donde se agotaron los tratamientos conservadores que tiene clínica dolorosa localizada en el lado afectado y con alteración del eje reductible, la prótesis unicompartimenal de rodilla (PUR) es la primera opción para nuestro grupo de trabajo. Dentro del estudio para confirmar el diagnóstico y planificar la cirugía destacan las radiografías de rodillas con carga, radiografía de Rosenberg y telerradiografías de extremidades inferiores. El objetivo de la cirugía es reemplazar la zona afectada, restituyendo la anatomía con un adecuado balance de partes blandas. Respecto al alineamiento el desafío es no sobrecargar el lado contrario ni tampoco el de la prótesis. Existen de platillo móvil y fijo y aunque los resultados clínicos y de supervivencia son semejantes, en los últimos años con la incorporación de la cirugía robótica, la balanza se ha inclinado para el uso de los platillos fijos. En pacientes con artrosis unicompartimental los resultados clínicos y funcionales son mejores con PUR y tiene menos complicaciones que cuando se usan prótesis totales (PTR). La supervivencia estudiada en registros es menor que para PTR, pero cuando se usa en centros de alto flujo en que el porcentaje de PUR es cercano a un tercio del total con una estricta selección de pacientes, la duración es tan buena como en la PTR.

Are ChatGPT's Free-Text Responses on Periprosthetic Joint Infections of the Hip and Knee Reliable and Useful?

BACKGROUND: This study aimed to evaluate ChatGPT's performance on questions about periprosthetic joint infections (PJI) of the hip and knee. METHODS: Twenty-seven questions from the 2018 International Consensus Meeting on Musculoskeletal Infection were selected for response generation. The free-text responses were evaluated by three orthopedic surgeons using a five-point Likert scale. Inter-rater reliability (IRR) was assessed via Fleiss' kappa (FK). RESULTS: Overall, near-perfect IRR was found for disagreement on the presence of factual errors (FK: 0.880, 95% CI [0.724, 1.035], p < 0.001) and agreement on information completeness (FK: 0.848, 95% CI [0.699, 0.996], p < 0.001). Substantial IRR was observed for disagreement on misleading information (FK: 0.743, 95% CI [0.601, 0.886], p < 0.001) and agreement on suitability for patients (FK: 0.627, 95% CI [0.478, 0.776], p < 0.001). Moderate IRR was observed for agreement on "up-to-dateness" (FK: 0.584, 95% CI [0.434, 0.734], p < 0.001) and suitability for orthopedic surgeons (FK: 0.505, 95% CI [0.383, 0.628], p < 0.001). Question- and subtopic-specific analysis revealed diverse IRR levels ranging from near-perfect to poor. CONCLUSIONS: ChatGPT's free-text responses to complex orthopedic questions were predominantly reliable and useful for orthopedic surgeons and patients. Given variations in performance by question and subtopic, consulting additional sources and exercising careful interpretation should be emphasized for reliable medical decision-making.

Cruciate-substituting and posterior-stabilised total knee arthroplasties had similar gait patterns in the short term.

PURPOSE: Surgeons want to achieve native kinematics in primary total knee arthroplasty (TKA). Cruciate-substituting (CS) implants could restore the knee kinematics more efficiently than posterior-stabilised (PS) TKA. This study aimed to compare gait patterns in patients with CS or PS TKA at 6 months. The hypothesis was that CS implants would demonstrate comparable gait parameters to PS implants at 6 months. METHODS: In this prospective case-control study, 38 primary TKA without coronal laxity were divided into 2 groups: 19 cruciate-substituting (CS) and 19 posterior-stabilised (PS) implants. The type of prosthesis was determined according to the surgical period. Exclusion criteria were TKA revision, associated procedures and inability to walk on a treadmill. Gait analysis was conducted on a treadmill 6 months postoperatively for each patient with a knee assessment device (KneeKG®). Gait characteristics included analysis in three spatial dimensions (flexion-extension, abduction-adduction, internal-external rotation, anterior-posterior translation). Clinical outcomes (Knee Society Score and Forgotten Joint Score) were compared between both groups at 6 months postoperatively. RESULTS: At 6 months, the gait analysis did not demonstrate any significant difference between CS and PS implants. The range and the maximum anteroposterior translation were similar in both groups (9.2 ± 6.5 mm in CS group vs. 8.1 ± 3 mm in PS group (n.s.); and - 5.2 ± 5 mm in CS group vs. - 6.3 ± 5.9 mm in PS group (n.s.), respectively). The internal/external rotation, the flexion, and the varus angle were similar between CS and PS implants. The KSS Knee score was higher at 6 months in the CS group than in the PS group (92.1 ± 5.6 vs. 84.8 ± 8.9 (p < 0.01)). CONCLUSION: Cruciate-substituting and posterior-stabilised TKA had similar gait patterns at 6 months postoperatively, despite a non-equivalent posterior stabilisation system. CS prostheses were an interesting option for primary TKA for knee kinematics restoration without requiring a femoral box. LEVEL OF EVIDENCE: Prospective, case-control study; Level II.

What to improve: Results of fixed-hinge knee endoprosthesis reconstructions over 40 years in a single tumor center.

INTRODUCTION: Over the past decades, numerous structural changes in implants, medical treatments, and surgical techniques have been made for Malignant Bone Tumors (MBT) around the knee. However, the overall care improvement is still unclear. The method is crucial when analyzing outcomes in surveys involving tumors, and a thorough assessment of the mortality is mandatory because death acts as competing event. The aims of this study were: 1) a comprehensive and longitudinal assessment of the revisions with an extensive follow-up and adequate methods; 2) a complete mortality review to consider competing risks. HYPOTHESIS: The hypothesis was that some prosthesis's structural improvements were made while the surgical toll increased as well as an improvement of mortality was also expected. MATERIAL AND METHODS: Analyses were performed on 248 patients with MBT (mean follow-up was 8.7 years, surgeries between 1972 and 2017). Three prosthesis models were successively used over time: 120 Guepar (older model), 42 Tornier, and 86 Stanmore (more recent model). The primary outcome was the assessment of revisions sorted out according to Henderson: type-1 soft-tissue failures or instability, type-2 aseptic loosening, type-3 structural failures, type-4 periprosthetic infections, type-5 tumoral progression. Death and amputations were considered as competing events. An extensive assessment of mortality was performed by merging the dataset with the French register of Deaths (INSEE). Cumulative probabilities were computed at 2, 5, 10, and 15 years and compared with Gray's tests. RESULTS: The overall 5-year survival was, 80% (95% CI: 73-87) for Guepar, 69% (95% CI: 56-84) for Tornier, and 71% (95% CI: 62-82) for Stanmore (p=0.4). The 5-year cumulative risks for type-1 were 5% (95% CI: 1-9), 9% (95% CI: 0-18), and 17% (95% CI: 9-25) for Guepar, Tornier, and Stanmore, respectively (p=0.01). The 15-year cumulative risks for type-2 were 22% (95% CI: 15-39), 8% (95% CI: 0-17) and 8% (95% CI: 2-14) for Guepar, Tornier, and Stanmore, respectively (p=0.10). Ten patients had an implant failure, nine Guepar, and one Tornier. The 5-year cumulative risks for type-4 were 7% (95% CI: 2-12), 19% (95% CI: 7-31), and 12% (95% CI: 5-18) for Guepar, Tornier, and Stanmore, respectively (p=0.08). There were 29 tumoral progressions; the 15-year risks were 16% (95% CI: 2-22), 2% (95% CI: 0-7%), and 12% (95% CI: 4-19%) for Guepar, Tornier, and Stanmore, respectively (p=0.08). No difference whatsoever was found between the proximal tibial and distal femur. CONCLUSION: There were some improvements in prosthesis design (forged steel instead of cast steel) and probably also in cemented stem fixation, but not in prosthetic joint infection and local recurrence over forty years. The overall mortality did not change significantly over the last 40 years amongst this specific cohort of patients who benefited from a hinge reconstruction prosthesis. LEVEL OF EVIDENCE: III; comparative case series with sensibility analysis.

The Length of Incision in Unicondylar Knee Arthroplasty Is More Affected by the Patient's Height Than Their Weight.

Objective Obesity leads to osteoarthritis due to increased loading forces on joint cartilage and inflammatory agents released from adipose tissue. In patients with a high body mass index (BMI), during hip and total knee arthroplasty, surgical technical challenges such as longer incisions and wider exposure are encountered, resulting in increased postoperative complications (wound healing problems and infection, venous thromboembolism (VTE)- pulmonary embolism (PE), dislocation, early implant failure) and ultimately decreased patient satisfaction and implant survival. This study investigates whether BMI, height, weight, and patient age are associated with longer incisions in patients undergoing unicondylar knee prosthesis (UKP) placement. Method Between January 2017 and December 2018, 30 patients (29 females and 1 male) who underwent UKP surgery due to medial gonarthrosis were included in the study. The UKP used in the procedures was the Oxford Knee Phase III by Biomet Ltd., UK. The study comprised 43 knees, 13 being bilateral cases, 8 on the right, and 9 on the left. Data regarding the patient's height, weight, BMI, age, and the operated side were collected and compiled. The relationships between these variables and the surgical incision length were statistically analyzed. Results The average age of the patients was 66.3 years, with an average weight and height of 77.6 kg (ranging from 62 to 98 kg) and 167 cm (ranging from 150 to 184 cm), respectively. The lengths of the surgical incisions ranged from 70 mm to 160 mm, with an average length of 124.5 mm. When comparing the incision lengths between the right and left sides, it was observed that the incisions on the left side were longer. The average incision length on the right side was 122.09 mm, while on the left, it was 126.86 mm. Moreover, in the 13 patients who underwent bilateral surgery, this difference in incision length was even more pronounced. The average incision length on the right side was 117.15 mm, whereas on the left, it was 124.23 mm. Bivariate correlation analyses were performed to examine the relationship between the length of the incision and BMI and age. However, no significant relationship was found between the incision length and BMI or age. On the other hand, there was a correlation between the patient's weight values and the incision length (p < 0.05, correlation 0.335). Furthermore, a higher correlation was observed between the patient's height and the incision length (p < 0.01, correlation 0.595). Conclusion The latest advances in surgical techniques and instrumentation have enabled surgeons to perform the procedure using a reliable mini-incision approach. Mid-term evaluation of UKP with mini-incision shows faster recovery and lower morbidity. The findings show that in UKP, the length of the surgical incision is more strongly related to the patient's height than their weight.

Medial tibial bone resorption following total knee arthroplasty comparing a traditional with a kinematic design.

BACKGROUND: New total knee prostheses are being designed to improve clinical outcome, survivorship and patient satisfaction following total knee arthroplasty (TKA). A new knee system was developed with improvements in patellofemoral joint, trochlear geometry, polyethylene formulation and tibial baseplate. Aim of this study was to compare the newer kinematic knee system with its existing predecessor knee system in terms of clinical outcome, revision rates, radiographic outcomes specifically medial tibial bone resorption. METHODS: The prospective matched-pair study included 88 TKA surgeries using newer kinematic design knee prostheses, performed between January 2015 and December 2016, out of which 82 patients were available for final follow-up. The control cohort of 82 traditional TKA prosthesis was matched in terms of age, gender and body mass index. All surgeries were performed by the single surgeon using medial parapatellar arthrotomy and posterior stabilized implants were used. Clinical outcomes were assessed using knee society score, range of motion (ROM), anterior knee pain and crepitation. Radiological examinations included recording of radiolucent lines and medial tibial bone resorption. RESULTS: At the 5-year follow-up, no significant differences were noted in terms of mean knee society score (93.3 ± 6.6 vs 94.2 ± 8.1), knee function score (88.5 ± 10.5 vs 89.1 ± 11.2) and ROM. The incidences of anterior knee pain and crepitation were lower in the newer group (8.5% vs 21.9% and 14.6% vs 32.9%, respectively) compared to the traditional prosthesis group. No cases of aseptic loosening were observed in either cohort. No significant difference was seen in terms of radiolucent lines (29.3% vs 26.8%) and medial tibial resorption (2.43% in each group) incidences. CONCLUSIONS: At the 5 years follow-up no significant differences were noted between the two groups in terms of clinical and radiological outcomes, except the former proved to be better for anterior knee pain and crepitation. LEVEL OF EVIDENCE: II.

Septic Metallosis after Unicompartmental Knee Replacement: A Case Report and Literature Review.

Introduction: Metallosis following prosthetic hip and knee replacement is a well-known complication. However, unicompartmental knee arthroplasty (UKA) metallosis is rare. In this paper, we report a case of septic metallosis after unicompartmental knee replacement and we review the literature for the available treatment options. Case Report: A 83-year-old female patient presented with left periprosthetic knee infection on the top of unicompartmental knee prosthesis three months after septic endocarditis that was treated with anti-biotherapy. Surgical exploration showed severe infected metallosis due to chronic polyethylene wear reaction; hence, management consisted of total synovectomy and debridement of all metallic debris and two stage revision. Conclusion: Metallosis is a well-known complication after prosthetic hip and knee replacements. However, in UKA, it remains a rare complication where only few cases were reported in the literature.

Design, Kinematics and Gait Analysis, of Prosthetic Knee Joints: A Systematic Review.

The aim of this review article is to appraise the design and functionality of above-knee prosthetic legs. So far, various transfemoral prosthetic legs are found to offer a stable gait to amputees but are limited to laboratories. The commercially available prosthetic legs are not reliable and comfortable enough to satisfy amputees. There is a dire need for creating a powered prosthetic knee joint that could address amputees' requirements. To pinpoint the gap in transfemoral prosthetic legs, prosthetic knee unit model designs, control frameworks, kinematics, and gait evaluations are concentrated. Ambulation exercises, ground-level walking, running, and slope walking are considered to help identify research gaps and areas where existing prostheses can be ameliorated. The results show that above-knee amputees can more effectively manage their issues with the aid of an active prosthesis, capable of reliable gait. To accomplish the necessary control, closed loop controllers and volitional control are integral parts. Future studies should consider designing a transfemoral electromechanical prosthesis based on electromyographic (EMG) signals to better predict the amputee's intent and control in accordance with that intent.

Diagnosis and management of METS-Stanmore Morse taper failure.

We describe clinical semiology in 6 cases of METS-Stanmore distal femoral Morse taper impaction failure: from obvious forms with intraprosthetic dislocation to chronic forms with less obvious symptoms: instability, piston sensation, rotational disorder in gait. The diagnostic procedure in chronic forms is described, notably with dynamic examination under fluoroscopy. Reduction and re-impaction by external maneuver can be attempted; in case of failure or of any suspicion of taper disassembly, the 2 modular implant components have to be replaced. Finally, we provide a review of the literature on this rare but serious complication. LEVEL OF EVIDENCE: IV.