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BACKGROUND: Studies have suggested that automated synovial cell counting may overestimate the white blood cell (WBC) count, resulting in false positive tests when evaluating patients for the possibility of periprosthetic joint infection (PJI) after THA. However, associations between WBC counts high enough to mimic PJI in patients whose arthroplasties are not infected but rather are experiencing a variety of aseptic problems—including but not limited to metallosis, polyethylene wear, and recurrent dislocation—have not, to our knowledge, been adequately addressed. In addition, there is a lack of analyses about the polymorphonuclear percentage (PMN%) when assessed by automated analyzers in this context. QUESTIONS/PURPOSES: In the context of different indications for aseptic revision and different periprosthetic hip pathologic findings, we asked: (1) What were the synovial WBC count levels, and what proportion of values were above the 2018 International Consensus Meeting (ICM) cutoff (3000 cells/μL)? (2) What were the synovial PMN% levels, and what proportion of values were above the 2018 ICM (70%)? METHODS: We retrospectively studied the preoperative cell count analyses of synovial fluid in patients who underwent revision THA for aseptic reasons at our tertiary referral arthroplasty center between January 2015 and December 2017. We considered all revisions performed on patients during that time potentially eligible, and after prespecified exclusions were applied (exclusions mainly included 15% [197 of 1306] sporadic missing data and 12% [155 of 1306] insufficient synovial fluid obtained in the aspirate), a total of 702 patients undergoing revision THA for aseptic reasons remained for the final analysis. As far as we know, no patients underwent re-revision for PJI at a mean follow-up of 46 ± 11 months, which tends to confirm our impression that indeed these hips did not have PJI. Cell count analyses were conducted using an automated analyzer. Clinical findings, preoperative radiographs, and surgical reports––confirmed by available histologic results––were used to establish diagnoses. We evaluated these hips considering the recommendations of the 2018 ICM (WBC count of 3000 cells/μL and PMN% of 70%) to see what proportion of them would have been characterized as likely having PJI on basis of those cutoff values. The mean WBC count for the entire cohort was 2120 ± 2395 cells/μL. The mean PMN% for the entire cohort was 36% ± 22%. RESULTS: Compared with aseptic loosening and recurrent dislocation, polyethylene wear had the highest mean WBC count (3817 ± 3711 cells/μL; p < 0.001). Of the investigated periprosthetic conditions, wear-induced synovitis had the highest value (4464 ± 3620 cells/μL; p < 0.001). Considering the ICM threshold, polyethylene wear showed the highest proportion of WBC counts above 3000 cells/μL among the indications for aseptic revision (60% [25 of 42]; p < 0.001). Of the periprosthetic conditions, wear-induced synovitis showed the highest proportion beyond the ICM cutoff (60% [50 of 83]; p < 0.001). The mean PMN% for aseptic causes ranged between 28% and 44% without differences among them (p = 0.12). Patients with metallosis had the highest mean PMN% of the periprosthetic conditions investigated (45% ± 25%; p = 0.007). Regarding the ICM threshold, metallosis resulted in the largest proportion of patients with a PMN% above 70% (21% [10 of 47]; p = 0.003), and that for wear-induced synovitis was 6% (5 of 83; p = 0.42) and for osteolysis was 3% (1 of 33; p = 0.51). There were no differences among aseptic loosening, recurrent dislocation, and polyethylene wear in terms of the proportion above 70% among the aseptic revision causes. CONCLUSION: Using automated cell counting, we found that WBC counts differ widely across indications for aseptic revision THA, and a high proportion of patients who underwent revision THA for aseptic reasons had WBC counts above the commonly used threshold of 3000 cells/μL. However, the PMN% was much less affected in several common indications for aseptic revision THA, making this measure more reliable for interpreting aspiration results using an automated analyzer. Based on the data distributions we observed, manual counting techniques might be considered in particular among patients with polyethylene wear, metal-on-metal bearing surfaces, or suspected metallosis. However, an elevated WBC count alone, observed using an automated analyzer in the context of polyethylene wear, should not be considered to be strongly suggestive of PJI, since that finding occurred so commonly among patients without infection. LEVEL OF EVIDENCE: Level III, diagnostic study.

Background Despite the growing number of studies reporting on periprosthetic joint infection (PJI), there is little information on one-stage exchange arthroplasty for the revision of infected rotating-hinge prostheses, which can be among the most difficult PJI presentations to treat. Questions/purposes After one-stage direct exchange revision for an infected rotating-hinge TKA prosthesis, and using a multimodal approach for infection control, we asked: (1) What is the survivorship free from repeat revision for infection and survivorship free from reoperation for any cause? (2) What is the clinical outcome, based on the Oxford Knee Score, of these patients at the latest follow-up? Methods Between January 2011 and December 2017, we treated 101 patients with infected rotating-hinge knee prostheses at our hospital. All patients who underwent a one-stage exchange using another rotating-hinge implant were potentially eligible for this retrospective study. During that period, we generally used a one-stage approach when treating PJIs. Eighty-three percent (84 of 101) of patients were treated with one-stage exchange, and the remainder were treated with two-stage exchange. Of the 84 treated with one-stage exchange, eight patients died of unrelated causes and were therefore excluded, one patient declined to participate in the study, and another eight patients were lost before the minimum study follow-up of 2 years or had incomplete datasets, leaving 80% (67 of 84) for analysis in this study. The included study population consisted of 60% males (40 of 67) with a mean age of 64 ± 8 years and a mean (range) BMI of 30 ± 6 kg/m2 (21 to 40). The mean number of prior surgeries was 4 ± 2 (1 to 9) on the affected knee. Fifteen percent (10 of 67) of knees had a preoperative joint communicating sinus tract, and 66% (44 of 67) had experienced a prior PJI on the affected knee. The antimicrobial regimen was chosen based on the advice of our infectious disease consultant and individually adapted for the organism cultured. The mean follow-up duration was 6 ± 2 years. Kaplan-Meier survivorship analysis was performed using the endpoints of survivorship free from repeat revision for infection and survivorship free from all-cause revision. The functional outcome was assessed using the Oxford Knee Score (on a 12- to 60-point scale, with lower scores representing less pain and greater function), obtained by interviewing patients for this study at their most recent follow-up visit. Preoperative scores were not obtained. Results The Kaplan-Meier analysis demonstrated an overall survivorship free from reoperation for any cause of 75% (95% CI 64% to 87%) at the mean follow-up of 6 years postoperatively. Survivorship free from any repeat operative procedure for infection was 90% (95% CI 83% to 97%) at 6 years. The mean postoperative Oxford Knee Score was 37 ± 11 points. Conclusion With an overall revision rate of about 25% at 6 years and the limited functional results based on the poor Oxford Knee Scores, patients should be counseled to have modest expectations concerning postoperative pain and function level after one-stage exchange of an infected rotating-hinge arthroplasty. Nevertheless, patients may be informed about a reasonable chance of PJI eradication and might opt for this approach as a means to try to avoid high transfemoral amputation or joint arthrodesis, which in this population often is associated with the inability to ambulate at all. Regarding the relatively high number of patients with aseptic loosening, future studies might focus on implant design of revision knee systems as well. A longer course of oral antibiotics after such procedures may also be warranted to limit the chance of reinfection but requires further study. Level of evidence Level IV, therapeutic study.

OBJECTIVES: This study aims to investigate the effectiveness of a screening questionnaire to identify high-risk patients for novel coronavirus-2019 (COVID-19) among those undergoing elective orthopedic surgery. PATIENTS AND METHODS: Between May 4th, 2020 and June 11th, 2020, a total of 1,021 consecutive patients (492 males, 529 females; mean age: 62.3±15.1 years; range, 13 to 91 years) who were scheduled for elective orthopedic surgery were included. A screening questionnaire was applied to all patients. The patients admitted to hospital were also tested for COVID-19 infection through reverse transcription-polymerase chain reaction of the nasopharyngeal swab. RESULTS: Of the patients, 1,003 (98.2%) underwent elective surgery as planned. The screening questionnaire classified 30 patients as high-risk for COVID-19. A total of 18 procedures (n=18, 1.8%) were postponed due to the high risk of possible transmission of COVID-19. None of 991 low-risk patients were tested positive for COVID-19. CONCLUSION: The use of guiding principles for resuming elective orthopedic surgery is safe without a higher risk for complications in selected cases.

Objectives This study aims to investigate if the use of intravenous (IV) tranexamic acid (TXA) during one-stage exchange for periprosthetic joint infection (PJI) of the hip that necessitates an extensive debridement is associated with decreased blood loss, if the rate of blood transfusion that may lead to side effects can be lowered with IV TXA, and if there is any difference regarding the occurrence of postoperative venous thromboembolism (VTE). Patients and methods We retrospectively reviewed patients who underwent one-stage exchange for PJI of the hip with perioperative IV administration of TXA (n=163; 90 males, 73 females; mean age 68±10.3; range, 25 to 90 years) between January 2015 and December 2016 and compared them to another group (n=190; 106 males, 84 females; mean age 71±10.1; range, 39 to 92 years) who underwent one-stage exchange for PJI of the hip without perioperative IV administration of TXA between January 2006 and December 2012. Blood loss, transfusion rates, amount of transfused blood, and occurrence of VTE complications were observed. Results Mean blood loss of the TXA group was significantly lower than that of the non-TXA group (2.4 L and 4.5 L, respectively; p

Background Dual-mobility cups have been shown to reduce the dislocation risk after THA. Although dual-mobility cups can be a useful strategy to mitigate against recurrent dislocation after revision surgery, few clinical studies have focused on the results of complex revision THAs with extensive bone and soft-tissue loss or in patients who have undergone more than one previous surgical procedure. Questions/purposes (1) What is the survival free from revision for dislocation of dual-mobility cups used in complex revision THAs? (2) What is the survival free from any dislocation? Methods Between January 1, 2009 and December 31, 2013, 327 patients underwent a complex revision THA that included an acetabular revision, defined as preexisting massive bone loss in the acetabulum (at least Paprosky Type 2B) and/or proximal femur (at least Paprosky Type 3), substantial gluteal soft-tissue involvement, at least two previous surgical procedures or a one-stage septic revision, or history of dislocation. All 327 complex revision patients received a dual-mobility cup. Of those, 34% (111) were lost to follow-up before 5 years and were not known to have reached a study endpoint (revision for dislocation, and any dislocation) before then, leaving 216 patients for analysis. For patients with bilateral hip surgeries only the first operated hip was included for analysis. The median (range) follow-up duration was 69 months (60 to 110). The primary endpoint was dislocation or re-revision for dislocation. Fifty-six percent (120 of 216) of the patients were women and 44% (96 of 216) were men. The mean age of the patients was 69 ± 9 years. The patients underwent a median of four surgical procedures (1 to 4) before the index procedure (the revision evaluated in this study). A survival analysis was performed using the Kaplan-Meier method; any dislocation or revision for dislocation was determined as the endpoint. Results The dislocation-free survival rates were 96% (95% confidence interval 92 to 98) at 5 years and 82% (95% CI 72 to 89) at 9 years. The overall dislocation rate was 11% (24 of 216 patients) at the final follow-up interval. Survival free of revision for dislocation was 99% (95% CI 96 to 100) at 5 years and 85% (95% CI 75 to 92) at 9 years. Conclusions Dual-mobility cups used in complex revision THA in this series had a higher rate of dislocation and revision than expected, based on earlier studies of dislocations of these components. Although we believe dual-mobility cups are still the first choice of implant if the patient has instability, these cups should be used cautiously if severe bone loss or soft-tissue involvement is present. Level of evidence Level III, therapeutic study.

Introduction. Periprosthetic joint infections caused by methicillin-resistant Staphylococcus aureus (MRSA-PJIs) are rare, with only a few studies reporting the treatment outcomes and even fewer reporting outcomes with one-stage exchange. Aim. This study aims to analyse the outcomes of one-stage exchange in the management of MRSA-PJIs. Methodology. Patients with MRSA-PJI of the hip and knee, who were treated with a one-stage exchange between 2001 and 2018 were enrolled in this study. The final cohort comprised of 29 patients, which included 23 hips and six knees. The mean follow-up was 5.3 years (1–9 years). Reinfection and complications rates after the one-stage exchange were analysed. Results. Overall infection control could be achieved in 93.1 % (27 out of 29 patients). The overall revision rate was 31.0% (9 patients), with three patients requiring an in-hospital revision (10.3 %). Six patients had to be revised after hospital discharge (20.7 %). Of the two reinfections, one had a growth of MRSA while the other was of methicillin-sensitive Staphyloccocus epidermidis. Conclusion. One-stage exchange surgery using current techniques could improve surgical outcomes with excellent results in the management of MRSA-PJIs.

Introduction The inner diaphyseal diameter of the distal femur, at 20 cm from the lateral joint line, is the strongest risk factor for predicting aseptic loosening in total knee arthroplasty using rotating hinge prosthesis. In this context, the Citak classification has been introduced presenting three different types of the distal femur anatomy. The aim of the study is to develop a novel classification system for the proximal tibia. Materials and Methods Two-hundred patients with standard knee antero-posterior radiographs were included in this study. We measured the inner diameter of the tibia 16 cm distally from the tibial plateau and 3 cm distally from the tibial spine. The ratio between these two measurements was applied as the novel index ratio. Results According to the 25th and 75th percentiles, three groups can be clustered for each gender. A higher distribution of the type B pattern was found in female and male patients. However, type A with a narrow inner diaphyseal diameter was less common in female patients The median intra-observer reliability for rater 1 was 0.997. The inter-observer reliability was high (ICC 0.998). There was a moderate correlation between the AP diameter and height (r = 0,568); a low correlation between the AP diameter and weight (r = 0.376). The novel index shows no significant correlation between the index ratio and height (r = 0.082), weight (r = 0.014) or BMI (r= - 0.038). The novel index shows no statistically significant correlation between the index ratio and height (r = 0.082) or weight (r = 0.014) or BMI (r= - 0.038). Conclusion The novel classification presents three different types of tibia for each gender: type C has a wider inner diaphyseal diameter compared to type A with a narrow inner diaphyseal diameter. Type B has the widest distribution among the subjects.

This study aims to analyze the in-hospital complication rates in patients with human immunodeficiency virus (HIV) following primary total knee (TKA) and total hip arthroplasty (THA).This retrospective study included a total of 37 patients including 11 patients undergoing TKA (11 males; mean age: 60.8±16.0 years; range, 48 to 80 years) and 26 patients undergoing THA (23 males, 3 females; mean age: 49.9±11.5 years; range, 35 to 70 years) between January 2010 and December 2019. The patients were evaluated in terms of body mass index (BMI), American Society of Anesthesiology (ASA) scores, pre and postoperative blood tests, indications for surgery, operative time, length of hospital stay, and in-hospital complications.The overall in-hospital complication rate following primary TKA (n=2, 18.2%) and THA (n=2, 7.7%) was 10.8%. Following TKA, one patient had deep vein thrombosis and one patient developed acute renal failure. In the THA group, postoperative delirium and trochanteric fracture were noted.The in-hospital complication rates increased in HIV-positive patients following TKA and THA. The risk of complications can be mitigated with the aid of a better interdisciplinary cooperation and thorough surgical planning.

Osteoarthritis of the hip joint (coxarthrosis) is the most common hip disease in adults. Since the 1960s, total hip arthroplasty (THA) has made great progress and is nowadays one of the most frequently used procedures in orthopedic surgery. Different bearing concepts exist in various implant designs. A metal-on-metal bearing can create metal debris and lead to metallosis. We present a unique case of a 78-year old woman, who received hip resurfacing with a McMinn-like prosthesis 15 years ago. Over the cause of time, metallosis developed and created a bone cyst in the Os ilium, and osteolysis led to a dislocation of the femoral implant. A minor stumble fall led to a fracture of the Os ilium. We present our treatment method with implantation of a cemented THA and refill of the bone cyst with bone from allogene femoral heads. The surgery led to a reconstruction of the physiological center of rotation in the hip. Consequently, to the inpatient stay, the patient took part in a follow-up treatment with intensive physiotherapy. Taken together, the results after total hip arthroplasty are more superior to other hip surface replacements in terms of longevity and patient satisfaction. Especially, metal-on-metal bearing couples carry a great risk of metallosis, which goes a long with pseudotumors, osteolysis, and the elevated metal ions in the blood. Since this case is unique in the literature, no guidelines are noted for surgical treatment. In our opinion, a periprosthetic fracture of this type should be performed in a hospital using extensive endoprosthetic expertise.

Heterotopic Ossification (HO) is a potential long-term complication in orthopaedic surgery. It is commonly classified according to the Brooker classification, which is based on radiological findings. To our knowledge the correlation of histological features to the Brooker grade is unknown as is the association between HO and the indication for revision. The aim of this paper is to analyze the ossification grade of HO tissue in patients undergoing revision hip and knee arthroplasty and to propose a histologically based classification system for HO. We also assess the relationship between the grade of HO and the indication for revision (septic and aseptic revision). From January to May 2019 we collected 50 human HO samples from hip and knee revision arthroplasty cases. These tissue samples were double-blinded and sent for histopathological diagnostic. Based on these results, we developed a classification system for the progression of HO. The grade of ossification was based on three characteristics: Grade of heterotopic ossification (Grade 1–3), presence of necrosis (N0 or N1) and the presence of osteomyelitis (HOES-Score Type 1 to 5). Demographic data as well as surgical details and indication for surgery was prospectively collected from clinical records. Fifty tissue samples were harvested from 44 hips and 6 knee joints. Of these 33 exhibited Grade I ossifications (66%), followed by 11 Grade II (22%) and one Grade III (2%). Necrosis was noted in two tissue samples (4%) and 2 more had osteomyelitis findings according to HOES-Score. Six samples (12%) with radiologically suggestive of HO turned out to be wear-induced synovitis, SLIM Type 1. Of these cases 16 were septic (32%) and 34 aseptic (68%) revisions. Most of the HO tissue samples were classified as a low-grade. High-grade ossification-Score is rare. Higher grades of ossification seem to be associated with septic revision cases. Wear-induced synovitis potentially influences HO development. A histological scoring system for ossification grading can be derived from the data presented in this study.

Little is known about the relationship between the virulence of pathogens in periprosthetic joint infection (PJI) and C-reactive protein (CRP) levels. In this context, we assessed the performance of CRP for PJI. We collected the following data from 987 cases of total joint revision due to PJI and 386 cases of aseptic revision: age, gender, comorbidities, values for serum CRP, leukocytes, microbiology for preoperatively taken aspirations and at least 2 intraoperative biopsies, and presence or absence of a draining sinus. The mean CRP value in the PJI group was 50.2 mg l−1 (sd=62.2), while a lower CRP value of 11.6 mg l−1 (sd=25.3) was found in the control group. There were no significant differences for the CRP values between patients with and without draining sinus (P=0.4423). The difference in CRP between high-virulence and low-virulence micro-organisms was significant for both the hip and the knee (P

Despite increased interest in one-stage revision arthroplasty for periprosthetic joint infection (PJI) of the hip, the reported infection-free proportions after the one-stage approach are still comparable to that of two-stage revision. However, we still lack studies that analyze factors associated with any re-revision after one-stage revision arthroplasty for PJI.After one-stage revision arthroplasty for PJI of the hip, what factors were associated with an increased risk of re-revision, and what factors were associated with an increased risk of reinfection?We performed a single-center retrospective case-control analysis. Patients who underwent one-stage revision arthroplasty for PJI of the hip in our hospital between 2009 and 2017, and who were subsequently re-revised due to any reason, including reinfection, were identified from our electronic medical records. A total of 121 patients who underwent repeat revision for any reason after one-stage exchange for PJI of the hip were identified. The re-revision procedures were performed after a mean of 407 days. The primary reasons for re-revision were repeated hip dislocation in 53 of 121 patients (44%), reinfection including both new and persistent infections in 40 of 121 patients (33%), and aseptic loosening in 16 patients (13%). Forty-three patients underwent another revision procedure after the re-revision procedure (43 of 121; 36%). More than 40 potential patient-, joint- and surgery-related risk factors were investigated and compared with a 1:1 matched control participants by age, sex and year of the one-stage revision. Similar to the re-revision patients, controls were treated for PJI with one-stage revision arthroplasty; however, they did not undergo subsequent revision for any reason by the latest followup examination. The mean followup of the control group was 66 months (range, 17-119 months). The mean length of hospital stay was 26 days in the re-revised group (SD, 11.6 days) compared with 22 days for the controls (SD, 6.6 days). All analyses were performed to identify factors associated with general re-revision and reinfection.The independent factors associated with repeat revision for any reason were persistent wound drainage for at least 1 week (odds ratio [OR], 7.4; 95% CI, 2.6-20.6; p0.001), isolation of enterococci (OR, 4.8; 95% CI, 1.4-15.7; p = 0.010), and prior surgery due to infection before the one-stage hip revision (OR, 3.6; 95% CI, 2.0-6.4; p0.001). The factors associated with reinfection including both new and persistent infections were prolonged wound drainage (OR, 6.9; 95% CI, 2.2-21.5; p = 0.001) and prior surgery due to infection (OR, 4.3; 95% CI, 1.9-9.5; p0.001).Prolonged wound drainage after the one-stage revision arthroplasty for PJI of the hip must be treated rigorously. Patients with a history of a prior surgical procedure due to hip infection should be informed about the risk of further re-revision when deciding for the one-stage exchange. In case of enterococcal isolation, surgeons may consider another treatment approach rather than the one-stage exchange. Furthermore, we recommend the use of dual mobility cups when performing the one-stage revision hip arthroplasty to reduce the risk of dislocation.Level of Evidence Level III, therapeutic study.

BACKGROUND The diagnosis of periprosthetic joint infection (PJI) after total shoulder arthroplasty (TSA) is challenging, especially in patients with Cutibacterium (formerly Propionibacterium) acnes infection. Despite the increasing number of patients with PJI of the shoulder, there are still no robust data regarding diagnostic tests in detecting shoulder PJI. QUESTIONS/PURPOSES (1) What are the sensitivity, specificity, and negative- and positive-predictive values for the alpha-defensin enzyme-linked immunosorbent assay test in detecting PJI after TSA? (2) What are the diagnostic accuracies in detecting shoulder PJI for synovial alpha-defensin, leukocyte esterase Test, and serum C-reactive protein (CRP)? METHODS All patients with painful TSA, who underwent joint aspiration to validate or exclude a PJI, between July 2015 and February 2018 were enrolled in this single-center study. Further indications for aspiration were as follows: planned revision arthroplasty, early loosening and clinical signs of infections, especially serum CRP elevation. A total of 121 patients were aspirated to exclude or verify a PJI, and 16 patients were excluded. In all, 105 patients with a mean age of 68 years (± 12 years) were included for analysis. Patients who underwent TSA were considered aseptic or septic according to the Musculoskeletal Infection Society criteria. Twenty-four patients had a PJI, and the remaining 81 patients were in the aseptic group. The microbiologic evaluation including polymicrobial infection showed C. (formerly P.) acnes in 15 patients (63%). Synovial fluid was then analyzed using microbiology cultures, alpha-defensin immunoassay, and leukocyte esterase. The specificity, sensitivity, and positive-predictive and negative-predictive values were calculated for each test. RESULTS The overall accuracy for alpha-defensin was 91% (95% confidence interval [CI], 84.4-96); sensitivity was 75% (95% CI, 53-90), specificity was 96% (95% CI, 90-99), negative predictive value was 93% (95% CI, 85-97), and positive predictive value was 86% (95% CI, 64-97). In contrast, the overall accuracy for leukocyte esterase was 76% (95% CI, 61-88), sensitivity was 50% (95% CI, 21-79), specificity was 87% (95% CI, 69-96), positive predictive value 60% (95% CI, 26-88) and negative predictive value was 81% (95% CI, 64-93). CONCLUSIONS Summarizing the study results, the alpha-defensin ELISA and leukocyte esterase tests had less sensitivity in detecting shoulder PJI than previously reported TKA or THA results. The quality and low amount of joint fluid is the difficult part of the diagnostic. C. (formerly P.) acnes was the most common cause of PJI. Focusing on low-grade infections, alpha-defensin has shown its advantages in diagnosing PJI regardless pathogen virulence. Since the diagnostic of a PJI is always a synopsis of findings, the alpha-defensin and leukocyte esterase test can be used as adjunct diagnostic tool in patients with painful TSA. We propose further prospective studies to improve the diagnostic and confirm the results. LEVEL OF EVIDENCE Level III, diagnostic study.

Purpose Bone loss is a challenging problem during revision total knee arthroplasty (TKA). Several studies have been published on the use of metaphyseal sleeves during revision TKA. Therefore, the aim of this systematic review was to summarize the clinical and radiographic outcomes of the use of metaphyseal sleeves in the setting of revision TKA. Methods A comprehensive search of PubMed, MEDLINE, CINAHL, Cochrane, EMBASE, and Google Scholar was performed, covering the period between January 1, 2000, and August 12, 2017. Various combinations of the following key words were used: “metaphyseal,” “sleeves,” “knee,” and “revision.” A total of 10 studies were included in the present systematic review. Results A total of 904 patients with 928 implants were recorded with a mean age of 69 years. They were evaluated at a mean follow-up of 45 months. Overall 1,413 sleeves, 888 in the tibia and 525 in the femur, were implanted. There were 36 septic re-revisions of the prosthetic components (4%). Five sleeves were found loose during septic re-revision; therefore, the rate of septic loosening of the sleeves was 0.35%. An aseptic re-revision of the prosthetic components was performed 27 times (3%). Ten sleeves were found loose during aseptic re-revision; therefore, the rate of aseptic loosening of the sleeves was 0.7%. Intraoperative fractures occurred 44 times (3.1%). Finally, clinical outcome was improved at final follow-up. Conclusion Metaphyseal sleeves demonstrate high radiographic signs of osteointegration, low septic loosening rate, low intraoperative fractures rate, and a good-to-excellent clinical outcome. Hence, they are a valid option to treat large metaphyseal bone defect during revision TKA. Level of Evidence This is a systematic review of level IV studies.

Introduction. Morquio syndrome or mucopolysaccharidosis (MPS) type IV is a rare autosomal recessive lysosomal storage disease, characterized by abnormal metabolism of glycosaminoglycans associated with specific skeletal deformities, also known as dysostosis multiplex. Case Presentation. We present the case of a 23-year-old patient with advanced osteonecrosis of the femoral head (ONFH) on both sides due to Morquio syndrome. A diagnosis of mucopolysaccharidosis type IVB was made after extensive genetic profiling. The patient had the condition for a long time. At 7 years old, the patient was treated with bilateral pelvic Salter’s osteotomy. Afterward, the patient was able to walk freely but could never take part in sports. At 22 years old, pain in the hip increased, and magnetic resonance imaging showed a bilateral femur head necrosis. Hence, the patient underwent cementless total hip arthroplasty (THA). Intraoperatively, a periprosthetic fracture occurred. Therefore, revision surgery with internal fixation was performed on the next day. Postoperatively, a weight-bearing restriction of 20 kg on the left leg was imposed for 6 weeks. The patient made a full recovery and was able to move without residual complaints. Annual orthopedic evaluation in patients treated with surgical intervention is recommended. Discussion. Orthopedic challenges for mucopolysaccharidoses and corresponding bone alterations, known as dysostosis multiplex, involving trunk and limbs with typical radiological findings have been well described. The hip is invariably involved, with dysplasia affecting the femoral neck (coxa valga), femoral epiphysis (loss of sphericity, osteonecrosis), and a flared hypoplastic iliac wing. Symptomatic therapy consists, on the one hand, of a surgical procedure and, on the other hand, a variety of supportive measures. However, the management of joint replacement in lysosomal storage diseases has not been well reported. All patients with MPS should be considered at high risk for surgical intervention requiring anesthesia because of airway and cardiac disease manifestations. In the case of a need for THA, we recommend cemented stem fixation because of the overall poor bone quality in patients with Morquio syndrome.

Despite growing evidence supporting the evaluation, classification, and treatment of acetabular bone loss in revision hip replacement, advancements have not been systematically incorporated into a single document, and therefore, a comprehensive review of the treatment of severe acetabular bone loss is needed. The Stavros Niarchos Foundation Complex Joint Reconstruction Center at Hospital for Special Surgery held an Acetabular Bone Loss Symposium on June 21, 2019, to answer the following questions: What are the trends, emerging technologies, and areas of future research related to the evaluation and management of acetabular bone loss in revision hip replacement? What constitutes the optimal workup and management strategies for acetabular bone loss? The 36 international experts convened were divided into groups, each assigned to discuss 1 of 4 topics: (1) preoperative planning and postoperative assessment; (2) implant selection, management of osteolysis, and management of massive bone loss; (3) the treatment challenges of pelvic discontinuity, periprosthetic joint infection, instability, and poor bone biology; and (4) the principles of reconstruction and classification of acetabular bone loss. Each group came to consensus, when possible, based on an extensive literature review. This document provides an overview of these 4 areas, the consensus each group arrived at, and directions for future research.

S. epidermidis is a substantial component of the human skin microbiota, but also one of the major causes of nosocomial infection in the context of implanted medical devices. We here aimed to advance the understanding of S. epidermidis genotypes and phenotypes conducive to infection establishment. Furthermore, we investigate the adaptation of individual clonal lines to the infection lifestyle based on the detailed analysis of individual S. epidermidis populations of 23 patients suffering from prosthetic joint infection. Analysis of invasive and colonizing S. epidermidis provided evidence that invasive S. epidermidis are characterized by infection-supporting phenotypes (e.g. increased biofilm formation, growth in nutrient poor media and antibiotic resistance), as well as specific genetic traits. The discriminating gene loci were almost exclusively assigned to the mobilome. Here, in addition to IS256 and SCCmec, chromosomally integrated phages was identified for the first time. These phenotypic and genotypic features were more likely present in isolates belonging to sequence type (ST) 2. By comparing seven patient-matched nasal and invasive S. epidermidis isolates belonging to identical genetic lineages, infection-associated phenotypic and genotypic changes were documented. Besides increased biofilm production, the invasive isolates were characterized by better growth in nutrient-poor media and reduced hemolysis. By examining several colonies grown in parallel from each infection, evidence for genetic within-host population heterogeneity was obtained. Importantly, subpopulations carrying IS insertions in agrC, mutations in the acetate kinase (AckA) and deletions in the SCCmec element emerged in several infections. In summary, these results shed light on the multifactorial processes of infection adaptation and demonstrate how S. epidermidis is able to flexibly repurpose and edit factors important for colonization to facilitate survival in hostile infection environments., Author summary S. epidermidis is a substantial component of the human skin microbiota, but also a major cause of nosocomial infections related to implanted medical devices. While phenotypic and genotypic determinants supporting invasion were identified, none appears to be necessary. By analysis of S. epidermidis from prosthetic joint infections, we here show that adaptive events are of importance during the transition from commensalism to infection. Adaptation to the infectious lifestyle is characterised by the development of intra-clonal heterogeneity, increased biofilm formation and enhanced growth in iron-free and nutrient-poor media, as well as reduced production of hemolysins. Importantly, during infection subpopulations emerge that carry mutations in a number of genes, most importantly the acetate kinase (ackA) and the β-subunit of the RNA polymerase (rpoB), have deleted larger chromosomal fragments (e.g. within the SCCmec element) or IS insertions in AgrC, a component of the master quorum sensing system in S. epidermidis. These results shed light on the multifactorial processes of infection adaptation and demonstrate how S. epidermidis is able to flexibly repurpose and edit factors important for colonization to facilitate survival under hostile infection conditions. While mobilome associated factors are important for S. epidermidis invasive potential, the species possesses a multi-layered and complex ability for adaptation to hostile environments, supporting the progression to chronic implant-associated infections.

Objectives This study aims to investigate the use of multiple blood management strategies and the effect of tourniquet on the estimated blood loss (EBL) in Jehovah's Witness (JW) patients who underwent primary total knee arthroplasty (TKA). Patients and methods Twenty-two self-reported JW patients (9 males, 13 females; mean age 66.8±8.6 years; range, 51 to 83 years) who underwent primary TKA between January 2014 and January 2020 in our institution were retrospectively reviewed. A standard blood management protocol that consisted of hypotensive anesthesia, local and systemic administration of tranexamic acid (TXA) and intraoperative cell salvage was applied to all patients. Patients were divided into two groups: with (n=11) and without (n=11) tourniquet use. The EBL was calculated according to Meunier's formula. Hemoglobin (Hgb), hematocrit (Hct), and EBL on the first and third postoperative days were compared statistically. Results There was no significant difference between groups regarding postoperative Hgb (p=0.801 and p=0.767), Hct (p=0.617 and p=0.895), Hgb decline (p=0.311 and p=0.822), and EBL (p=0.067 and p=0.284) at first and third postoperative days. None of the patients required blood transfusion. No wound complication or symptomatic deep vein thrombosis was seen during the hospital stay. Conclusion Combined use of hypotensive anesthesia, intravenous administration of TXA, intraoperative periarticular injection, and cell salvage seem to be sufficient in controlling the blood loss in JW patients during TKA. Additional tourniquet use may not further decrease the EBL.

Background: Controversies exist regarding the association of elevated serum glycated haemoglobin (HbA1c) levels and postoperative surgical site infection (SSI) or prosthetic joint infection (PJI) in the setting of total hip and knee arthroplasty (THA and TKA). The purpose of the current study was to determine the prevalence of unknown and uncontrolled diabetes mellitus (DM) in a consecutive series and to investigate the association between postoperative wound complications or SSI/PJI and elevated HbA1c in patients undergoing TJA. Methods: In this prospective single-centre study, HbA1c was determined for patients undergoing elective primary, aseptic or septic revision THA and TKA, between September 2017 and March 2018. Prevalence of DM, unknown and uncontrolled diabetes were reported. Occurrence of 90-day wound healing disorders (WHD) as well as SSI or PJI were observed. Considering the HbA1c threshold ⩾6.5%, a comparative analysis between patients with and without WHD and SSI or PJI for the whole study cohort, as well as for each arthroplasty group, was performed. Receiver operating characteristic (ROC) curves were developed to quantify the predictive power of HbA1c with regard to WHD and infection complications. A total of 1488 patients were included for final analysis. There were 1127 primary THA and TKA (75.7%), 272 aseptic revisions (18.3%) and 89 septic revisions (6.0%). The known diabetic patients constituted 9.9% of the whole study cohort. Results: The majority had uncontrolled DM (67%). Prevalence of unknown DM was 11.1%. The results reveal the prevalence for the German population and might be different in other regions. A total of 57 patients (3.7%) experienced postoperative wound or infectious complications. PJI occurred in only 5 patients (0.03%). There was no significant difference between patients with HbA1c Conclusions: We demonstrated that prevalence of unknown and uncontrolled DM in patients undergoing TJA is increasing, however; routine preoperative determination of the HbA1c value to prevent possible postoperative wound or infectious complications remains debatable. Larger studies investigating the optimal HbA1c level, as well as other predictors are required.

Introduction: Identification of the pathogen in case of a periprosthetic joint infection (PJI) remains 1 of the greatest challenges in septic surgery. Rapid germ identification enables timely, specific, antimicrobial therapy. The first multiplex PCR (polymerase chain reaction) generation (Unyvero-i60) enables germ detection within 5 hours with a sensitivity of 78.8% and a specificity of 100%. The aim of this study is to investigate the performance of the new generation of cartridges (Unyvero-ITI) of multiplex PCR in the case of a PJI. Methods: In a prospective study, intraoperatively aspirated synovial fluid from 97 patients with aseptic or septic hip or knee revision surgery (49 aseptic, 48 septic) was examined with the multiplex PCR system (Unyvero-ITI) and the results were compared with the MSIS criteria. In addition, the time until the microbiological result was obtained in the event of a germ detection was documented. Results: The multiplex PCR showed a germ detection with a sensitivity of 85.1% and a specificity of 98.0%. In 7 cases a false negative result was found and in one patient a false positive result was found. The general accuracy of this test procedure was 91.8%. The detection of germs was carried out within 5 hours with the multiplex PCR compared to 4.9 days in conventional microbiological diagnostics. Conclusions: The new generation of multiplex-PCR was able to improve germ detection. The possibility of prompt detection of germs offers the option of faster, targeted antimicrobial therapy. This diagnostic tool offers significant advantages, particularly in the context of an acute periprosthetic infection.

The successful use of allografts in reconstructive orthopedic surgery, including revision total hip arthroplasty (THA), has been outlined repeatedly. Nonetheless, as previous studies were primarily based on clinical follow-ups, we aimed to create an algorithm that accurately determines the extent of allograft incorporation in the acetabulum and femur using a suite of high-resolution imaging techniques. This study is based on a large patient database including > 4,500 patient data with previous revision THA and simultaneous use of allografts. While the database was continuously matched with the deceased individuals at the local forensic medicine department, complete hips were retrieved in case of a positive match. A positive match was achieved for n = 46 hips at a mean follow-up of 11.8 ± 5.1 years. Comprehensive imaging included contact radiography, high-resolution computed tomography (HR-pQCT), undecalcified histology of ground sections and quantitative backscattered electron imaging (qBEI). We here define a histomorphometric toolkit of parameters to precisely characterize the incorporation of structural (bulk) and morselized (chip) allografts in the acetabulum (n = 38) and femur (n = 8), including the defect area and interface length, microstructural and cellular bone turnover parameters as well as overlap and fibrosis thickness. This collection of samples, through its unique study design and precise definition of incorporation parameters, will provide the scientific community with a valuable source for further in-depth investigation of allograft incorporation and, beyond that, the regenerative potential of this osteoconductive scaffold.

Background Over the last years, new transfusion guidelines and pharmaceuticals have been introduced in primary and revision total hip and knee arthroplasty (P-THA, P-TKA, R-THA, R-TKA). In the US, a substantial decrease in transfusions has been observed in recent years. Little data exists on the subject in Europe. In this context we aimed to analyze: (1) Is there also a significant decrease in blood transfusion for these procedures in Germany? (2) Which patient and hospital related factors are associated with the risk of blood transfusion? (3) Is there a trend in complications, especially venous thromboembolism and stroke events that can be linked to tranexamic acid use? Hypothesis There is a significant trend in decreasing blood transfusions in hip and knee arthroplasty. Methods Using nationwide healthcare insurance data for inpatient hospital treatment, 736,061 cases treated between January 2011 and December 2017 were included (318,997 P-THAs, 43,780 R-THAs, 338,641 P-TKAs, 34,643 R-TKAs). Multivariable logistic regression was used to model the odds of transfusion as a function of the year of surgery. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated. Results In each cohort the odds of transfusion decreased over time (2017 vs. 2011 (reference): P-THA: OR 0.42 (95%CI: 0.39–0.45), P-TKA: OR 0.41 (95%CI: 0.37–0.46), R-THA: OR 0.52 (95%CI: 0.47–0.58), R-TKA: OR 0.53 (95%CI: 0.46–0.61). Patient-related risk factors for blood transfusion included older age, female gender, lower Body Mass Index, comorbidities such as renal failure, cardiac arrhythmia, congestive heart failure, valvular disease, coagulopathy, depression, and antithrombotic medication prior to surgery. Venous thromboembolism or stroke events did not increase over the study period. Discussion The incidence of blood transfusions in primary and revision TKA and THA decreased over the study period. This may be due to new transfusion guidelines and the introduction of novel pharmaceuticals such as tranexamic acid. A further improved patient blood management and a focus on vulnerable patient groups might lead to a further future reduction of transfusions, especially in R-THA. Level of Evidence III; comparative observational study.

Background Total hip arthroplasty (THA) is frequently accompanied by acetabular bone loss, which constitutes a major challenge in revision procedures. Structural allografts can be implanted to restore a stable osseous foundation for the acetabular prosthesis. As previous studies were limited to clinical data or included very few cases, the extent to which the graft bone is incorporated over time has remained unclear. Methods Thirteen acetabula were retrieved post mortem, and the incorporation properties of the bone allografts were analyzed using a hierarchical approach of imaging techniques including contact radiography, high-resolution peripheral quantitative computed tomography (HR-pQCT), histological analysis of undecalcified specimens, and quantitative backscattered electron imaging (qBEI). The distance between the current allograft bone and host bone borders (i.e., current overlap) as well as the distance between the original allograft bone and host bone borders (i.e., total ingrowth) were assessed. Results In 10 of 13 cases, the complete interface (100%) was characterized by direct contact and additional overlap of the allograft bone and host bone, while the remaining 3 cases demonstrated direct contact along 25% to 80% of the interface. The allograft bone showed an intact trabecular structure and significantly higher mineralization compared with the host bone. The mean current overlap (and standard deviation) was 2.3 ± 1.0 mm, with a maximum of 5.3 ± 2.4 mm. Importantly, the total ingrowth reached much further, to a mean of 7.2 ± 2.3 mm (maximum, 10.5 ± 4.0 mm). Neither the time that the allograft was in situ nor the degree of contact between the host and allograft bone correlated with the current overlap and the time in situ did not correlate with total ingrowth. Conclusions This study showed bone remodeling with subsequent interconnection of the host and allograft bone along the majority of the interface, leading to adequate incorporation of the allograft. The lack of complete incorporation of the graft did not lead to graft collapse up to 22 years after revision surgery. Clinical relevance Our study provides the first systematic multiscale evaluation of successfully implanted structural allografts and forms the scientific basis for their clinical use in revision THA.

High-volume hospitals have achieved better outcomes for THAs and unicompartmental knee arthroplasties (UKAs). However, few studies have analyzed implant survival after primary TKA in high-volume centers. Is the risk of revision surgery higher when receiving a TKA in a low-volume hospital than in a high-volume hospital? Using nationwide billing data of the largest German healthcare insurer for inpatient hospital treatment, we identified 45,165 TKAs in 44,465 patients insured by Allgemeine Ortskrankenkasse who had undergone knee replacement surgery between January 2012 and December 2012. Revision rates were calculated at 1 and 2 years in all knees. The hospital volume was calculated using volume quintiles of the number of all knee arthroplasties performed in each center. We used multiple logistic regression to model the odds of revision surgery as a function of hospital volume. Age, sex, 31 comorbidities, and variables for socioeconomic status were included as independent variables in the model. After controlling for socioeconomic factors, patient age, sex, and comorbidities, we found that having surgery in a high-volume hospital was associated with a decreased risk of having revision TKA within 2 years of the index procedure. The odds ratio for the 2-year revision was 1.6 (95% CI, 1.4–2.0; p < 0.001) for an annual hospital volume of 56 or fewer cases, 1.5 (95% CI, 1.3–1.7; p < 0.001) for 57 to 93 cases, 1.2 (95% CI, 1.0–1.3; p = 0.039) for 94 to 144 cases, and 1.1 (95% CI, 0.9–1.2; p = 0.319) for 145 to 251 cases compared with a hospital volume of 252 or more cases. We found a clear association of higher risk for revision surgery when undergoing a TKA in a hospital where less than 145 arthroplasties per year were performed. The study results could help practitioners to guide potential patients in hospitals that perform more TKAs to reduce the overall revision and complication rates. Furthermore, this study underscores the importance of a minimum hospital threshold of arthroplasty cases per year to get permission to perform an arthroplasty. Level III, therapeutic study.

Purpose Identification of bacteria and susceptibility are fundamental in periprosthetic joint infection (PJI). Especially in the case of systemic inflammatory response syndrome (SIRS) rapid detection of pathogens is essential for proper therapy. Bacterial cultures are time consuming. The polymerase chain reaction (PCR) is a non-culture molecular method and is able to rapidly identify pathogens and their resistance genes. Multiplex PCR (mPCR) can amplify several different DNA sequences simultaneously. The aim of this study was to show the value of mPCR for early diagnosis of PJI.Methods 60 patients undergoing total hip or knee revisions were recruited in this prospective single-centre-study. Three groups were created: 26 patients with aseptic loosening (negative control), 26 patients with chronic PJI, and 8 patients with acute PJI/SIRS. We compared the results of joint aspirates obtained intraoperatively investigated by mPCR with the microbiology results of tissue specimens.Results The overall sensitivity of mPCR was 78.8% (95% CI, 61.1 - 91.0%), the specificity was 100% (95% CI, 87.2 - 100%), the negative predictive value was 79.4% (95% CI, 62.1 - 91.3%), the positive predictive value was 100% (95% CI, 86.8 - 100%), and the overall accuracy was 88.3% (95% CI, 77.4 - 95.2%). The overall accuracy in acute infections/SIRS (87.5%) was greater than in late chronic PJI (76.9%). In PJI the mPCR was able to provide the results within 5 hours whereas the mean time for cultures was 6.4 days.Conclusions Multiplex PCR is a reliable diagnostic tool in PJI management, especially in acute cases complicated with SIRS. Early diagnosis within several hours is possible, targeted antibiotic treatment can be started promptly.

The World Health Organization (WHO) and the Centre for Disease Control and Prevention (CDC) recently published guidelines for the prevention of surgical site infection. The WHO guidelines, if implemented worldwide, could have an immense impact on our practices and those of the CDC have implications for healthcare policy in the United States. Our aim was to review the strategies for prevention of periprosthetic joint infection in light of these and other recent guidelines. Cite this article: Bone Joint J 2017;99-B(4 Supple B):3–10.

A key issue in the treatment of periprosthetic joint infection (PJI) is the correct diagnosis. The main problem is lack of diagnostic tools able to diagnose a PJI with high accuracy. Alpha-defensin has been proposed as a possible solution, but in the current literature, there is a lack of independent validation.We performed a prospective study to determine (1) what is the sensitivity, specificity, and positive and the negative predictive values of the alpha-defensin immunoassay test in diagnosing PJI; and (2) which clinical features may be responsible for false-positive and false-negative results?Preoperative aspiration was performed in all patients presenting with a painful hip/knee arthroplasty, including both primary and revision implants. Metallosis, other inflammatory comorbidities, and previous/concomitant antibiotic therapy were not considered as exclusion criteria. An inadequate amount of synovial fluid for culture was an exclusion criterion. A total of 156 patients (65 knees, 91 hips) were included in this prospective study. At the time of revision, synovial fluid samples were taken to perform the alpha-defensin assay. During surgical débridement of tissue, samples for cultures and histologic evaluation were taken, and samples were cultured until positive or until negative at 14 days. A diagnosis of PJI was confirmed in 29 patients according to the International Consensus Group on PJI.The sensitivity of the alpha-defensin immunoassay was 97% (95% confidence interval [CI], 92%-99%), the specificity was 97% (95% CI, 92%-99%), the positive predictive value was 88% (95% CI, 81%-92%), and the negative predictive value was 99% (95% CI, 96%-99%). Among four false-positive patients, two had metallosis and one had polyethylene wear. The false-negative case presented with a draining sinus, and intraoperative cultures were also negative.Alpha-defensin assay appears to be a reliable test, but followup evaluation is needed to estimate longer term performance of the test. The authors believe that alpha-defensin has demonstrated itself to be sufficiently robust that PJI diagnostic criteria now should include this test. Future studies are needed to compare the differences among the diagnostic capability of the available tests, in particular when metallosis is present, because metallosis may predispose the test to a false-positive result.Level I, diagnostic study.

Periprosthetic joint infection is a serious disease with severe consequences for the patient's life. It is not known whether one-stage or two-stage replacement arthroplasty is superior. So far, there have been no studies on short-term complications between both surgical procedures. Therefore, we performed a retrospective study aiming to determine: 1) Does two-stage septic exchange arthroplasty have a higher short-term complication rate than one-stage? 2) Is there a difference in length of hospital stay and the in-hospital mortality rate between two- and one-stage septic exchange arthroplasty?Two-stage septic exchange arthroplasty has a higher short-term complication rate than one-stage.Retrospectively 429 patients who underwent a one- or two stage revision arthroplasty (288 hips and 141 knees) due to chronic PJI between January 2015 and December 2016 were recruited (one-stage: n=385, two-stage: n=44). Differences in postoperative complications, surgical therapy, ASA, Charlson Comorbidity Index (CCI), length of hospital, need for plastic surgery, pathogen, in-hospital morbidity and in-hospital mortality were compared using multiple logistic and Poisson regression. Regarding comorbidities, age, gender and BMI the groups were comparable.It was 3.5 times more likely to suffer from a medical complication if a two stage septic exchange was performed (OR 3.465, (95% CI: 2.573-4.358) [p0.01]). In medical complications the two-stage group showed significantly more events (two-stage: 9 of 44=20.5%; one-stage: 30 of 385=7.8% [p=0.013]). The one-stage group showed more (not significant) nerve palsies after hip septic exchange. There was no difference in mortality between the groups (two-stage: 1/44=2.3%; one-stage: 3/385=0.8% [p=0.882]), the overall mortality was 0.93%. The duration of hospital stay was 23.9±19 days for the one-stage and 42.2±17.7 days for the two-stage group (p0.001).We found that it is more likely to develop a medical complication after two-stage septic revision arthroplasty. There was no difference in overall surgical complications between the two surgical approaches. We did not find a significant difference in short term mortality between the two techniques, although the mortality rate was slightly higher in the two-stage group.III, retrospective case control study.

Background The use of hinged designs is usually reserved for severe deformities or instability in contemporary total knee arthroplasty (TKA). Results have been mixed with some authors reporting relatively high incidences of complications. The aim of this study is to present the results of primary TKA performed with a hinged prosthesis with a minimum 10-year follow-up. We also examined the factors that influence survivorship of this prosthesis. Methods A total of 238 primary TKA procedures were performed using hinged prostheses. Indications included osteoarthritis, rheumatoid arthritis, posttraumatic deformity, and arthritis. Clinical outcomes were assessed using the Hospital for Special Surgery score. Radiologic assessment was performed at each follow-up. Survivorship was calculated based on the Kaplan-Meier method. All complications were documented. Results Mean follow-up was 13.5 years (standard deviation [SD], 3.4). Mean flexion at final review was 118° (SD, 20°). Fifty-four percent and 20% reported excellent and good functional scores, respectively. Survivorship was 94% at 13.5 years in patients over 60 years of age and 77% in patients less than 60 years of age. Survivorship in patients with preoperative varus deformity was 96% and that in valgus knees was 79%. Conclusions The results of this study suggest that when rotating hinges are used for primary TKA, the best results are achieved in patients over 60 years old. The indications for this design in the setting of primary TKA include significant deformities, severe bone loss, and ligamentous laxity.

Modular hip stems offer many advantages in revision arthroplasty. However, the region of modularity is prone to failure. Fracture of the non-cemented fluted tapered titanium Modular Prosthesis (MP) stem is relatively rare. We present here a case of a distal non-traumatic fracture of the MP stem and review the previously reported cases. A 53-years old, relatively active, male patient with a body mass index (BMI) of 37 kg/m2 had a fracture of the non-cemented MP stem on the left side after five years without complaints. The BMI was 45 at the time of implantation of the MP stem. His weight was significantly reduced, but the stem failed and fractured at an atypical site, quite distal to the modular junction. The broken stem with a relatively small diameter had been exchanged to a larger one. Fracture of the non-cemented fluted proximally-modular distally-tapered titanium MP stem might occur after years. Even in cases of good bone quality of the proximal femur, patient BMI and activity level should be considered when selecting the stem diameter. Furthermore, proximal bone loss of the femur should be considered as a potential cause of failure.