Medial-Pivot Design Improved Knee Symptoms From Anteroposterior Instability in Early-Range Flexion and Resolved Anterior Knee Pain in Revision Total Knee Arthroplasty.

BACKGROUND: Instability can lead to poor functional results after tricompartmental total knee arthroplasty (TKA). We identified a group of patients who appeared to have anteroposterior (AP) instability in early-range flexion (ie, 20 to 30° range) associated with anterior knee pain and feelings of instability. The purpose of this study was to assess the clinical results in terms of stability and anterior knee pain after revision TKA with a medial-pivot implant and to assess the effect of the implant positioning used in the revision technique. METHODS: There were 45 patients (45 knees) evaluated retrospectively to assess standing lower extremity alignment and functional results by generating a knee stability score after revision TKA with medial pivot implant design. RESULTS: Revision TKA using the medial-pivot TKA lowered the joint line by 3.6 millimeters (mm) (P < .001) and positioned the tibia anteriorly by 3.5 mm (P < .001) on radiographic measurements as compared with results after primary TKA. Moreover, medial pivot revision TKA improved AP stability by a 56-point change in score (P < .001). CONCLUSION: Revision TKA using a medial pivot design improved AP stability and anterior knee pain after failed primary procedures.

The impact of obesity on the outcome of severe SARS-CoV-2 ARDS in a high volume ECMO centre: ECMO and corticosteroids support the obesity paradox.

PURPOSE: The aim was to verify the impact of obesity on the long-term outcome of patients with severe SARS-CoV-2 ARDS. MATERIALS AND METHODS: The retrospective study included patients admitted to the high-volume ECMO centre between March 2020 and March 2022. The impact of body mass index (BMI), co-morbidities and therapeutic measures on the short and 90-day outcomes was analysed. RESULTS: 292 patients were included, of whom 119(40.8%) were treated with veno-venous ECMO cannulated mostly (73%) in a local hospital. 58.5% were obese (64.7% on ECMO), the ECMO was most frequent in BMI > 40(49%). The ICU mortality (36.8% for obese vs 33.9% for the non-obese, p = 0.58) was related to ECMO only for the non-obese (p = 0.04). The 90-day mortalities (48.5% obese vs 45.5% non-obese, p = 0.603) of the ECMO and non-ECMO patients were not significantly influenced by BMI (p = 0.47, p = 0.771, respectively). The obesity associated risk factors for adverse outcome were age <50 (RR 2.14) and history of chronic immunosuppressive therapy (RR 2.11, p = 0.009). The higher dosage of steroids (RR 0.57, p = 0.05) associated with a better outcome. CONCLUSIONS: The high incidence of obesity was not associated with worse short and long-term outcomes. ECMO in obese patients together with the use of steroids in the later stage of ARDS may improve survival.

Surgical conditions with rocuronium versus suxamethonium in cesarean section: a randomized trial.

BACKGROUND: Onset times and conditions for intubation after rocuronium versus suxamethonium at cesarean section have been evaluated, but no study thus far has examined the influence of these neuromuscular blocking drugs on the surgical conditions or their effect on the duration of surgery and the ease of fetal delivery. We aimed to compare the surgical conditions for delivery in parturients who received deep neuromuscular block with rocuronium with those who had induction with suxamethonium. METHODS: Ninety patients undergoing cesarean section under general anesthesia were randomized to receive either rocuronium 0.6 mg/kg or suxamethonium 1 mg/kg for tracheal intubation and delivery. Times to delivery and the quality of surgical conditions, using a five-point Surgical Rating Scale for Delivery (SRSD) ranging from 1 (poor) to 5 (excellent), were evaluated. RESULTS: The median SRSD (range) was found to be significantly better in the rocuronium group [4 (3-5) points vs 3 (2-4) points with suxamethonium (P <0.001)]. Whereas the mean (SD) induction-to-intubation interval was longer with rocuronium [106 (34) s vs 68 (32) s with suxamethonium (95% CI of the difference 24 to 52 s, P <0.001)], the incision-to-delivery interval was shorter in the rocuronium group [147 (68) s vs 196 (51) s with suxamethonium (95% CI of the difference -75 to -24 s, P <0.001)]. The mean induction-to-delivery intervals were similar [268 (73) s vs 276 (63) s, respectively]. CONCLUSIONS: Whereas the induction-to-delivery intervals were comparable, we found rocuronium superior to suxamethonium in allowing better surgical conditions for fetal delivery, which enabled an easier delivery and a shorter incision-to-delivery interval.

Labor analgesia in Czech Republic and Slovakia: a 2015 national survey.

BACKGROUND: The purpose of this international survey was to describe the current practices and techniques of labor analgesia in the Czech Republic (CZE) and Slovakia (SVK). METHODS: All Czech and Slovak departments that provide obstetric anesthesia were invited to participate in a one-month (November 2015) prospective study that monitored in detail all peripartum anesthetic procedures delivered by anesthesiologists. Participating centers recorded all data on-line in the CLADE-IS database (Masaryk University, CZE). RESULTS: The response rate was 71% (70 of 95 departments in CZE, 35 of 54 centers in SVK). Participating centers represented 87.7% of all births in CZE and 66.4% of all births in SVK during the study period. Analgesia for labor, administered by anesthesiologists, was recorded in 12.5% of deliveries (CZE 12.1%, SVK 13.4%). Epidural analgesia was used in most of the cases (CZE 97.2%, SVK 99.1%) whereas spinal (CZE 1.4%, SVK 0.9%) or combined spinal-epidural (CZE 0.5%, SVK 0.0%) and intravenous remifentanil analgesia (CZE 2.4%, SVK 0.0%) were used infrequently. One fifth of the labors with analgesia administered by anesthesiologists (CZE 20.2%, SVK 20.5%) terminated in cesarean section. CONCLUSIONS: Although labor analgesia was available in all Czech and Slovak obstetric centers, only a small proportion of parturients received an effective method of labor pain relief (regional or intravenous analgesia).

The Quadriceps Vector is Most Parallel to the Spherical Axis With Minimal Difference for Gender or Ethnicity.

BACKGROUND: The extensor mechanism may be the key to kinematic alignment of total knee arthroplasty. The purpose of this study was to determine any differences in the direction of the quadriceps vector based on gender or ethnicity and to determine which anatomically derived alignment axis is closest to the quadriceps vector. METHODS: Computed tomography scans and patient records for 14 Caucasians (9 men and 5 women) and 40 Japanese (19 men and 21 women) were evaluated. Three axes of alignment-anatomic, mechanical, and spherical-were identified, measured, and compared to the quadriceps vector in each case. Principal component analysis was used to determine the quadriceps vector by using 3-dimensional models of muscles on computed tomography scans. RESULTS: No statistically significant differences in the orientation of the quadriceps vector were found based on gender or ethnicity, and the quadriceps vector was most closely aligned with the spherical axis. CONCLUSION: Because the quadriceps is the primary knee extensor, the spherical axis therefore may be a ubiquitous guide to alignment of the arthroplasty knee based on motion.

High Risk of Failure With Bimodular Femoral Components in THA.

BACKGROUND: The bimodular femoral neck implant (modularity in the neck section and prosthetic head) offers several implant advantages to the surgeon performing THAs, however, there have been reports of failure of bimodular femoral implants involving neck fractures or adverse tissue reaction to metal debris. We aimed to assess the results of the bimodular implants used in the THAs we performed. QUESTIONS/PURPOSES: We asked: (1) What is the survivorship of the PROFEMUR(®) bimodular femoral neck stems? (2) What are the modes of failure of this bimodular femoral neck implant? (3) What are the major risk factors for the major modes of failure of this device? METHODS: Between 2003 and 2009, we used one family of bimodular femoral neck stems for all primary THAs (PROFEMUR(®) Z and PROFEMUR(®) E). During this period, 277 THAs (in 242 patients) were performed with these implants. One hundred seventy were done with the bimodular PROFEMUR(®) E (all are accounted for here), and when that implant was suspected of having a high risk of failure, the bimodular PROFEMUR(®) Z was used instead. One hundred seven THAs were performed using this implant (all are accounted for in this study). All bearing combinations, including metal-on-metal, metal-on-polyethylene, and ceramic-on-ceramic, are included here. Data for the cohort included patient demographics, BMI, implant dimensions, type of articular surface, length of followup, and C-reactive protein serum level. We assessed survivorship of the two stems using Kaplan-Meier curves and determined the frequency of the different modes of stem failure. For each of the major modes of failure, we performed binary logistic regression to identify associated risk factors. RESULTS: Survivorship of the stems, using aseptic revision as the endpoint, was 85% for the patients with the PROFEMUR(®) E stems with a mean followup of 50 months (range, 1-125 months) and 85% for the PROFEMUR(®) Z with a mean followup of 50 months (range, 1-125 months)(95% CI, 74-87 months). The most common modes of failure were loosening (9% for the PROFEMUR(®) E), neck fracture (6% for the PROFEMUR(®) Z and 0.6% for the PROFEMUR(®) E), metallosis (1%), and periprosthetic fracture (1%). Only the bimodular PROFEMUR(®) E was associated with femoral stem loosening (odds ratio [OR] =1.1; 95% CI, 1.04-1.140; p = 0.032). Larger head (OR = 3.2; 95% CI, 0.7-14; p = 0.096), BMI (OR = 1.19; 95% CI, 1-1.4; p = 0.038) and total offset (OR = 1.83; 95% CI, 1.13-2.9; p = 0.039) were associated with neck fracture. CONCLUSION: Bimodular neck junctions may be potentiated by long neck lengths, greater offset, and larger head diameters. These factors may contribute to bimodular neck failure by creating a larger moment about the neck's insertion in the stem. The PROFEMUR(®) E implant is associated with high periprosthetic loosening. Based on our experience we cannot recommend the use of bimodular femoral neck implants. LEVEL OF EVIDENCE: Level III, therapeutic study.

Maternal and neonatal effects of remifentanil in women undergoing cesarean section in relation to ABCB1 and OPRM1 polymorphisms.

The aim of our study was to evaluate possible effect of ABCB1, and OPRM1 polymorphisms on the efficacy and safety of remifentanil in women undergoing elective cesarean section under general anesthesia. Women received remifentanil (1 microg/kg i.v.) 30 s prior to the induction to standardized general anesthesia. The ABCB1 (rs2032582, rs1045642) and OPRM1 (rs1799971) polymorphisms were analyzed from maternal peripheral blood. The basal hemodynamic and demographic parameters in the study population (n=54) were similar in all the subgroups. The median +/- SD increase of systolic blood pressure at 5 min from the baseline was practically completely abolished in homozygous carriers of ABCB1 variants in comparison with wild-type subjects -2.67+/-25.0 vs. 16.57+/-15.7 mm Hg, p<0.05 for rs2032582, and 2.00+/-23.9 vs. 22.13+/-16.8 mm Hg, p<0.05, for rs1045642, respectively. While no neonate belonging to ABCB1 wild-type homozygous or OPRM1 variant carrying mothers needed any resuscitative measure, 10.5 % of the neonates belonging to OPRM1 wild-type homozygous mothers received resuscitative support similarly as 11.1 %, and 12.5 % of neonates of mothers carrying variants of rs2032582, and rs1045642, respectively. Decreased stabilizing effects of remifentanil on maternal hemodynamics has been observed in ABCB1 wild type mothers, while the adaptation of the neonates was clinically worse in OPRM1 wild type, and ABCB1 variant allele carriers.

[Analgesia for labour in the Czech Republic in the year 2011 from the perspective of OBAAMA-CZ study - prospective national survey]. / Analgezie u porodu v Ceské republice v roce 2011 z pohledu studie OBAAMA-CZ- prospektivní observacní studie.

GOAL OF THE STUDY: The aim of national survey was to describe current practice for analgesia during labour provided by anaesthesiologists in the Czech Republic (CZE). TYPE OF THE STUDY: National prospective observational. SETTING: 49 obstetric departments in CZE. METHODS: We aimed to enrol all 97 obstetric departments in CZE and to monitor every case of anaesthetic care in peripartum period during November 2011. Data were recorded to Case Report Form with two parts (Demography 2010 and Case Report) into TrialDB database (Yale University, USA; adapted IBA, MU, CZE). Demographic data for CZE were obtained on request by ÚZIS. The data were analysed using SPSS 22. RESULTS: We enrolled 1943 cases of anaesthesiological care and 579 (29.8%) of them was to relief labour pain. Population and center weighted estimate of incidence of epidural labour analgesia was 12.5% (95% CI: 10.6% - 14.4%). Epidural analgesia was the most frequently applied via Tuohy needle G18 (97.8%), with administration of an epidural catheter G20 (95.7%), via medial approach (98.8%), in lateral position (76.7%) by the loss of resistance method (94.3%). All administrations of epidural analgesia were started by initial bolus, only in 28.2% of cases were followed continously. Always has been applied mixture of local anaesthetic with sufentanil at a dose of 3-10 mcg. Bupivacaine was most frequently used local anaesthetic (80.7%), followed by levobupivacaine (12.6%). Median concentrations both bupivacaine and levobupivacaine were 0.125% (min. 0.1%, max. 0.3%).The most common complication of epidural analgesia was repeated puncture (21.2%), blood in the catheter (1.4%), blood in the needle (1.2%), unintended puncture of the dura mater (0.7%) and transient paresthesias (0.5%). CONCLUSION: In comparison to previously published data there was trend for lower incidence of epidural analgesia for labour in the CZE.

Midterm clinical and radiographic results of the medial pivot total knee system.

PURPOSE: The ADVANCE® Medial Pivot Knee System was designed with a highly congruent medial compartment and a less conforming lateral compartment to more closely mimic the kinematics of the normal knee. The purpose of this study was to evaluate the midterm clinical and radiographic outcomes of this total knee arthroplasty (TKA) system. METHODS: Between January 1998 and December 2006, 421 primary TKAs were performed in 373 subjects using this system and a surgical technique that resects the posterior cruciate ligament. Of these, 365 TKAs in 320 subjects were available for a follow-up visit occurring at a mean of 5.3 years. Subjects were evaluated using Knee Society Scores, range of motion, and radiographic review. RESULTS: The average Knee Society clinical score was 95.5 at final follow-up, with 358 (98%) TKAs having excellent or good results. Range of motion increased from a preoperative mean of 115 to 119° at final follow-up. Component survivorship, excluding revisions for infection or trauma, was 96.6% at five years. CONCLUSIONS: This study demonstrates subjects implanted with the ADVANCE® Medial Pivot Knee System achieved satisfactory clinical and radiographic midterm outcomes.

Analysis of a retrospective double-centre data-collection for the treatment of burns using biological cover Xe-derma®.

Xe-Derma(®) is a new biological acellular temporary wound cover derived from pig dermis in the form of a mesh of collagen and elastic fibers. It is recommended for use in similar indications as classical pig xenografts. A data collection of 2 burns centres in the treatment of burns with Xe-Derma(®) was obtained from the medical records of 101 patients admitted from January 1, 2010 to December 31, 2011. The primary objectives of the study were to assess efficacy and safety when using Xe-Derma(®) in burn treatment, and to analyse the course of healing. The secondary objectives were to define the suitable spectrum of indications of Xe-Derma(®) in terms of burn depth, and to evaluate subsequent scarring using the Vancouver Scar Scale. No undesirable systemic effects or adverse device events were observed. The use of Xe-Derma(®) was not associated with a higher risk of burn wound infection. On the other hand, the infection was the most common cause of Xe-Derma(®) dissolution. The majority of patients (81.4%) had no signs of Xe-Derma(®) dissolution. The mean healing time in the group of patiens under review was close to 12 days and mean hospitalization time was almost 14 days. Using Xe-Derma(®) proved to be effective as a temporary covering for partial-thickness burns with the capacity of spontaneous healing. It proved to be a well-tolerated wound coverage with minimal complications and low level of pain during dressing changes. Xe-Derma(®) firmly adhered to the wound bed. There was a lower frequency of wound dressing changes and only a minimal rate of wound infection.

Le Xe-Derma® est un nouveau pansement acellulaire biologique provisoire à base de derme porcin, se présentant sous la forme d'un filet de fibres de collagène et d'élastine. Son utilisation est recommandée dans les indications similaires aux xenogreffes porcines classiques. Nous avons recueilli et analysé les données de 101 patients, dont les brûlures ont été traitées par Xe- Derma® dans 2 centres de grands brûlés entre le 1er janvier 2010 et le 31 décembre 2011. L'objectif principal de cette étude consistait à évaluer l'efficacité et la sécurité de l'utilisation du Xe-Derma® pour le traitement des brûlures et d'analyser le processus de guérison. Les objectifs secondaires étaient de déterminer un spectre d'indications pour l'utilisation du Xe-Derma® selon la gravité de la brûlure et d'évaluer le processus de cicatrisation consécutif à l'aide de la VSS (Vancouver Scar Scale, échelle cicatricielle de Vancouver). Aucun effet systémique défavorable ou effet local indésirable n'a été observé. L'utilisation du Xe-Derma® n'a pas été associée à un risque plus élevé d'apparition d'infections de la plaie. En revanche, les infections ont représenté la cause la plus fréquente de dissolution du Xe-Derma®. La majorité des patients (81,4%) n'ont toutefois manifesté aucun signe de dissolution du Xe-Derma®. Quelle que soit la gravité de la brûlure, le durée moyenne de guérison était proche de 12 jours et la durée moyenne d'hospitalisation était de presque 14 jours. L'utilisation du Xe-Derma® s'est avérée efficace en tant que pansement provisoire sur les brûlures de second degré, présentant un potentiel de guérison spontanée. Le Xe-Derma® est un pansement bien toléré, causant peu de complications et réduisant la douleur lors des changements de pansement. Il adhère très bien au fond de la plaie. La faible fréquence de changement de pansement a permis de limiter les infections des brûlures.

Cardiac surgery increases serum concentrations of adipocyte fatty acid-binding protein and its mRNA expression in circulating monocytes but not in adipose tissue.

Adipocyte fatty acid binding protein (A-FABP) is a novel adipokine involved in the regulation of lipid and glucose metabolism and inflammation. To evaluate its potential role in the development of postoperative hyperglycemia and insulin resistance we assessed A-FABP serum concentrations and mRNA expression in skeletal and myocardial muscle, subcutaneous and epicardial adipose tissue and peripheral monocytes in 11 diabetic and 20 age- and sex-matched non-diabetic patients undergoing elective cardiac surgery. Baseline serum A-FABP did not differ between the groups (31.1+/-5.1 vs. 25.9+/-4.6 ng/ml, p=0.175). Cardiac surgery markedly increased serum A-FABP in both groups with a rapid peak at the end of surgery followed by a gradual decrease to baseline values during the next 48 h with no significant difference between the groups at any timepoint. These trends were analogous to postoperative excursions of plasma glucose, insulin and selected proinflammatory markers. Cardiac surgery increased A-FABP mRNA expression in peripheral monocytes, while no effect was observed in adipose tissue or muscle. Our data suggest that circulating A-FABP might be involved in the development of acute perioperative stress response, insulin resistance and hyperglycemia of critically ill irrespectively of the presence of diabetes mellitus.

Bone creep and short and long term subsidence after cemented stem total hip arthroplasty (THA).

Stem-cement and cement-bone interfacial failures as well as cement fractures have been noted in cemented total hip arthroplasty (THA) as the cause of aseptic loosening. Attempts to reduce the risk of femoral component loosening include improving the stem-cement interface by various coatings, using a textured or porous coated stem surfaces or by using a tapered stem having a highly-polished surface. The latter approach, often referred to as "force-closed" femoral stem design, would theoretically result in stem stabilization subsequent to debonding and 'taper-lock'. Previous work using three-dimensional finite element analysis has shown a state of stress at the stem-cement interface indicative of 'taper-lock' for the debonded stem and indicated that stem-cement interface friction and bone cement creep played a significant role in the magnitudes of stresses and subsidence of the stem. However, the previous analysis did not include the viscoelastic properties of bone, which has been hypothesized to permit additional expansion of the bone canal and allow additional stem subsidence (Lu and McKellop, 1997). The goal of this study was to investigate the effect of bone viscoelastic behavior on stem subsidence using a 3D finite element analysis. It was hypothesized that the viscoelastic behavior of bone in the hoop direction would allow expansion of the bone reducing the constraint on bone over time and permit additional stem subsidence, which may account for the discrepancies between predicted and clinical subsidence measurements. Analyses were conducted using physiological loads, 'average peak loads' and 'high peak loads' for 'normal patient' and 'active patient' (Bergmann et al., 2010) from which short and long term subsidence was predicted. Results indicated that bone creep does contribute to higher stem subsidence initially and after 10 years of simulated loading. However, it was concluded that the "constraint" upon the cement mantle is not mitigated enough to result in stem subsidence equivalent to that observed clinically.

[Childbirth analgesia and anesthesia in the Czech Republic in 2012. The 20th anniversary of post-graduate education]. / Porodnická analgezie a anestezie v Ceské republice v roce 2012 20. výrocí programu postgraduálního vzdelávání

The aim of this study was to ascertain the current status of analgesia and anesthesia used during childbirth in the Czech Republic. Using data from questionnaires, an overview of individual labor-related anesthetic procedures and methods and frequency of their use was obtained. A positive trend in the increase of neuroaxial methods used in maternity wards over the last twenty years has been the result of a systematic program of interdisciplinary post-gradual education for doctors and birth attendants in the Czech Republic.

[Peripartal life-threatening hemorrhage - interdisciplinary consensus opinion]. / Peripartální zivot ohrozující krvácení - mezioborové konsenzuální stanovisko.

22 experts from the fields of gynecology and obstetrics, anesthesiology and resuscitation, intensive care, hematology and transfusion medicine has developed recommendations for diagnosis and procedure for life-threatening peripartum haemorrhage, which is still one of the most common causes of maternal mortality in childbirth. This guidelines, which is valid for the Czech Republic, supported by a total of 10 professional medical societies. There are based on new knowledge applicable at this time and is focused mainly on eliminating the most common causes of bleeding during delivery and prevention of haemorrhagic shock.

Assessment of a medial pivot total knee arthroplasty design in a cadaveric knee extension test model.

A total knee has been designed to mimic less-compliant medial and more-compliant lateral behavior. In vivo testing compared open-kinematic chain behaviors of cadaver knees in their normal state and after implantation of the knee prosthesis. Specimen's limbs were computed tomography scanned, and infrared arrays on tibia and femur were registered to bone markers. Motion of the joint and quadriceps force were reported from 90° flexion to full extension. Less medial and more lateral anterior-posterior motion was seen in both the intact and the implanted knees. Tibiofemoral rotation and translation were similar in direction but were reduced in magnitude for the prosthetic knees. Quadriceps force, defined as that applied force required to extend the knee, required after implantation was variable between specimens but not statistically different from the intact condition. The prosthesis tested exhibits kinematic behavior similar to that in their normal state, with no difference in quadriceps force required for extension.

Increased circulating and epicardial adipose tissue mRNA expression of fibroblast growth factor-21 after cardiac surgery: possible role in postoperative inflammatory response and insulin resistance.

We studied the changes in serum fibroblast growth factor-21 (FGF-21) concentrations, its mRNA, and protein expression in skeletal muscle and adipose tissue of 15 patients undergoing cardiac surgery. Blood samples were obtained: prior to initiation of anesthesia, prior to the start of extracorporeal circulation, upon completion of the surgery, and 6, 24, 48, and 96 hours after the end of the surgery. Tissue sampling was performed at the start and end of surgery. The mean baseline serum FGF-21 concentration was 63.1 (43.03-113.95) pg/ml and it increased during surgery with peak 6 hours after its end [385.5 (274.55-761.65) pg/ml, p < 0.001], and returned to baseline value [41.4 (29.15-142.83) pg/ml] 96 hours after the end of the surgery. Serum glucose, insulin, CRP, IL-6, IL-8, MCP-1, and TNF-alpha concentrations significantly increased during the surgery. Baseline FGF-21 mRNA expression in skeletal muscle was higher than in both adipose tissue depots and it was not affected by the surgery. Epicardial fat FGF-21 mRNA increased after surgery. Muscle FGF-21 mRNA positively correlated with blood glucose levels at the end of the surgery. Our data suggest a possible role of FGF-21 in the regulation of glucose metabolism and insulin sensitivity in surgery-related stress.

Kneeling is safe for patients implanted with medial-pivot total knee arthroplasty designs.

Nine ADVANCE (Wright Medical Technology, Arlington, TN)) Medial-Pivot (MP) and 9 ADVANCE Double-High total knee arthroplasties were analyzed under radiographic surveillance at standing, mid kneeling, and full kneeling. In vivo tibiofemoral contact positions were obtained using the 3- to 2-dimensional image registration technique. The contact in Double-High knee was always more posterior than that in the MP knee presumably because of the presence of the posterior cruciate ligament. The contact positions in both the designs moved anterior from standing to mid kneeling, moved posterior from mid kneeling to full kneeling, and remained within the intended articulation range of the implants. This study indicates that kneeling is safe in MP total knee arthroplasty even in the absence of a cam-post or posterior cruciate ligament.

Total hip arthroplasty modular neck failure.

The use of modular components in total hip arthroplasty has increased in popularity. The advantages of modularity in hip arthroplasty include improved visualization during acetabular revision and restoration of proper hip biomechanics. Disadvantages include disassociation of components, failure at modular junctions, corrosion, and the generation of metal ions and debris. We present 2 cases that demonstrate the potential for modular neck fracture, requiring subsequent revision of well-fixed components.