Diagnosing periprosthetic hip joint infection with new-generation 0.55T MRI.

PURPOSE: To assess the accuracy of 0.55 T MRI in diagnosing periprosthetic joint infection (PJI) in patients with symptomatic total hip arthroplasty (THA). MATERIAL AND METHODS: 0.55 T MRI of patients with THA PJI (Group A) and noninfected THA (Group B), including aseptic loosening (Group C, subgroup of B) performed between May 2021 and July 2023 were analysed retrospectively. Two musculoskeletal fellowship-trained radiologists independently identified MRI bone and soft tissue changes including: marrow oedema, periosteal reaction, osteolysis, joint effusion, capsule oedema and thickening, fluid collections, muscle oedema, bursitis, inguinal adenopathy, and muscle tears. The diagnostic performance of MRI discriminators of PJI was evaluated using Fisher's exact test (p < 0.05) and interrater reliability was determined. 61 MRI scans from 60 THA patients (34 female, median age 68, range 41-93 years) in Group A (n = 9; female 4; median age 69, range 56-82 years), B (n = 51; 30; 67.5, 41-93 years), and C (10; 6; 67; 41-82 years) were included. RESULTS: Capsule oedema (sensitivity 89 %, specificity 92 %,), intramuscular oedema (89 %, 82 %) and joint effusion (89 %, 73 %) were the best performing discriminators for PJI diagnosis (p ≤ 0.001), when viewed individually and had combined 70 % sensitivity and 100 % specificity for PJI diagnosis in parallel testing. For the differentiation between PJI and aseptic loosening, intramuscular oedema (89 %, 80 %) and capsule oedema (89 %, 80 %) were significant discriminators (p ≤ 0.001) with combined 64 % sensitivity and 96 % specificity for PJI. CONCLUSIONS: New generation 0.55 T MRI may aid in the detection of PJI in symptomatic patients. Oedema of the joint capsule, adjacent muscles as well as joint effusion were indicative of the presence of PJI.

Association of preoperative beta-blocker use and cardiac complications after major noncardiac surgery: a prospective cohort study.

INTRODUCTION: Cardiac complications after major noncardiac surgery are common and associated with high morbidity and mortality. How preoperative use of beta-blockers may impact perioperative cardiac complications remains unclear. METHODS: In a multicentre prospective cohort study, preoperative beta-blocker use was ascertained in consecutive patients at elevated cardiovascular risk undergoing major noncardiac surgery. Cardiac complications were prospectively monitored and centrally adjudicated by two independent experts. The primary endpoint was perioperative myocardial infarction or injury attributable to a cardiac cause (cardiac PMI) within the first three postoperative days. The secondary endpoints were major adverse cardiac events (MACE), defined as a composite of myocardial infarction, acute heart failure, life-threatening arrhythmia, and cardiovascular death and all-cause death after 365 days. We used inverse probability of treatment weighting to account for differences between patients receiving beta-blockers and those who did not. RESULTS: A total of 3839/10 272 (37.4%) patients (mean age 74 yr; 44.8% female) received beta-blockers before surgery. Patients on beta-blockers were older, and more likely to be male with established cardiorespiratory and chronic kidney disease. Cardiac PMI occurred in 1077 patients, with a weighted odds ratio of 1.03 (95% confidence interval [CI] 0.94-1.12, P=0.55) for patients on beta-blockers. Within 365 days of surgery, 971/10 272 (9.5%) MACE had occurred, with a weighted hazard ratio of 0.99 (95% CI 0.83-1.18, P=0.90) for patients on beta-blockers. CONCLUSION: Preoperative use of beta-blockers was not associated with decreased cardiac complications including cardiac perioperative myocardial infarction or injury and major adverse cardiac event. Additionally, preoperative use of beta-blockers was not associated with increased all-cause death within 30 and 365 days. CLINICAL TRIAL REGISTRATION: NCT02573532.

Role of the Gastrocnemius Musculocutaneous with a Propeller Style Skin Flap in Knee Region Reconstruction: Indications and Pitfalls.

Background Soft tissue reconstruction around the knee area is still an open question, particularly in persistent infections and multiple reoperations scenario. Flap coverage should guarantee joint mobility and protection, even when foreign materials are implanted. The chimeric harvesting of the musculocutaneous gastrocnemius flap, based on the sural artery perforators, can extend its applicability in soft tissue reconstruction of the upper leg, overcoming the drawbacks of the alternative pedicled flaps. Methods A multicenter retrospective study was conducted enrolling patients who underwent to a pedicled, chimeric gastrocnemius musculocutaneous-medial sural artery perforator (GM-MSAP) or lateral sural artery perforator (GM-LSAP) flap for knee coverage in total knee arthroplasty (TKA) recurrent infections and oncological or traumatic defects of the upper leg from 2018 to 2021. Outcomes evaluated were the successful soft tissue reconstruction and flap complications. Surgical timing, reconstruction planning, technique, and rehabilitation protocols were discussed. Results Twenty-one patients were included in the study. Nineteen GM-MSAPs and 2 GM-LSAPs were performed (soft tissue reconstruction in infected TKA [12], in infected hardware [4], and in oncological patients [5]). Donor site was closed primarily in 9 cases, whereas a skin graft was required in 12. Flap wound dehiscence (1), distal flap necrosis (1), distal necrosis of the skin paddle (1), and donor site infection (1) were the encountered complications. Flap reraise associated to implant exchange or extensive debridement was successful without requiring any further flap surgery. Conclusion The propeller-perforator GM-MSAP offers qualitative defect coverage and easiness of multiple flap reraise due to skin availability and its laxity.

Use of Short Stems in Revision Total Hip Arthroplasty: A Retrospective Observational Study of 31 Patients.

Background and Objectives: Implantation of a short femoral stem in revision total hip arthroplasty (rTHA) could reduce the perioperative time, soft tissue damage, and preserve the bone stock of the proximal femur. The objective of this study was to describe the clinical and radiographic outcomes after the use of short stems in rTHA with a follow-up of 1 to 5 years. Materials and Methods: This retrospective, single center, and observational study analyzed the data of 31 patients (12 female, 19 male) with a median (interquartile range) age of 68.2 years (61.2-78.4) and BMI of 26.7 kg/m2 (24.6-29.4) who received an uncemented short femoral stem in rTHA between 2015 and 2020. Clinical outcomes were extracted from medical reports and assessed using the modified Harris Hip Score (mHHS), the numerical rating scale (NRS) for pain and satisfaction, and the UCLA Physical Activity Score. Radiographs were analyzed for stem subsidence, fixation, and bone parameters. The Wilcoxon test was used for pre-post rTHA differences (p < 0.05); clinical relevance was interpreted based on effect sizes according to Cohen's d. Results: All the clinical outcome measures improved significantly (p ≤ 0.001) at follow-up compared to preoperative status, with large effect sizes (Cohen's d) ranging from 2.8 to 1.7. At the last follow-up, the median (interquartile) mHHS was 80.9 (58.6-93.5). Stem fixation was stable in all cases. Complications included stem subsidence of 3 mm (n = 1) and 10 mm (n = 1), heterotopic ossification Brooker stage III (n = 2), intraoperative femur perforation (n = 1), periprosthetic fracture Vancouver type A (n = 1), and dislocation (n = 2). Conclusions: The good clinical results in our selective study population of patients with mild to moderate bone deficiency, supported by large effect sizes, together with a complication rate within the normal range, support the consideration of short stems as a surgical option after a thorough preoperative analysis.

Guideline adherence to statin therapy and association with short-term and long-term cardiac complications following noncardiac surgery: A cohort study.

BACKGROUND: Peri-operative complications are common and associated with high morbidity and mortality. Optimising the use of statins might be of important benefit in peri-operative care and reduce morbidity and mortality. OBJECTIVE: To evaluate adherence to current guideline recommendations regarding statin therapy and its association with peri-operative and long-term cardiac complications. DESIGN: Prospective cohort study. SETTING: Multicentre study with enrolment from October 2014 to February 2018. PATIENTS: Eight thousand one hundred and sixteen high-risk inpatients undergoing major noncardiac surgery who were eligible for the institutional peri-operative myocardial injury/infarction (PMI) active surveillance and response program. MAIN OUTCOME MEASURES: Class I indications for statin therapy were derived from the current ESC Clinical Practice Guidelines during the time of enrolment. PMI was prospectively defined as an absolute increase in cTn concentration of the 99th percentile in healthy individuals above the preoperative concentration within the first three postoperative days. Long-term cardiac complications included cardiovascular death and spontaneous myocardial infarction (MI) within 120 days. RESULTS: The mean age was 73.7 years; 45.2% were women. Four thousand two hundred and twenty-seven of 8116 patients (52.1%) had a class I indication for statin therapy. Of these, 2440 of 4227 patients (57.7%) were on statins preoperatively. Adherence to statins was lower in women than in men (46.9 versus 63.9%, P  < 0.001). PMI due to type 1 myocardial infarction/injury (T1MI; n  = 42), or likely type 2 MI (lT2MI; n  = 466) occurred in 508 of 4170 (12.2%) patients. The weighted odds ratio in patients on statin therapy was 1.15 [95% confidence interval (CI) 1.01 to 1.31, P  = 0.036]. During the 120-day follow-up, 192 patients (4.6%) suffered cardiovascular death and spontaneous MI. After multivariable adjustment, preoperative use of statins was associated with reduced risk; weighted hazard ratio 0.59 (95% CI 0.41 to 0.86, P  = 0.006). CONCLUSION: Adherence to guideline-recommended statin therapy was suboptimal, particularly in women. Statin use was associated with an increased risk of PMI due to T1MI and lT2MI but reduced risk of cardiovascular death and spontaneous MI within 120 days. TRIAL REGISTRATION: Clinicaltrials.gov identifier NCT02573532.

Prediction of perioperative myocardial infarction/injury in high-risk patients after noncardiac surgery.

AIMS: Perioperative myocardial infarction/injury (PMI) is a surprisingly common yet difficult-to-predict cardiac complication in patients undergoing noncardiac surgery. We aimed to assess the incremental value of preoperative cardiac troponin (cTn) concentration in the prediction of PMI. METHODS AND RESULTS: Among prospectively recruited patients at high cardiovascular risk (age ≥65 years or ≥45 years with preexisting cardiovascular disease), PMI was defined as an absolute increase in high-sensitivity cTnT (hs-cTnT) concentration of ≥14 ng/L (the 99th percentile) above the preoperative concentration. Perioperative myocardial infarction/injury was centrally adjudicated by two independent cardiologists using serial measurements of hs-cTnT. Using logistic regression, three models were derived: Model 1 including patient- and procedure-related information, Model 2 adding routinely available laboratory values, and Model 3 further adding preoperative hs-cTnT concentration. Models were also compared vs. preoperative hs-cTnT alone. The findings were validated in two independent cohorts. Among 6944 patients, PMI occurred in 1058 patients (15.2%). The predictive accuracy as quantified by the area under the receiver operating characteristic curve was 0.73 [95% confidence interval (CI) 0.71-0.74] for Model 1, 0.75 (95% CI 0.74-0.77) for Model 2, 0.79 (95% CI 0.77-0.80) for Model 3, and 0.74 for hs-cTnT alone. Model 3 included 10 preoperative variables: age, body mass index, known coronary artery disease, metabolic equivalent >4, risk of surgery, emergency surgery, planned duration of surgery, haemoglobin, platelet count, and hs-cTnT. These findings were confirmed in both independent validation cohorts (n = 722 and n = 966). CONCLUSION: Preoperative cTn adds incremental value above patient- and procedure-related variables as well as routine laboratory variables in the prediction of PMI.

[Plastic-surgical reconstruction of the lower extremity in senior patients]. / Plastisch-chirurgische Rekonstruktion der unteren Extremität bei alten Patienten.

The proportion of patients in the population beyond the 7th decade of life is increasing worldwide, especially in highly developed countries. Consequently, there is also an increasing need for complex lower extremity reconstructions after trauma, tumors, or infections in this age group. The reconstruction of soft tissue defects of the lower extremity should be performed according to the principle of the plastic-reconstructive ladder or elevator. The goal of reconstruction is to restore anatomy and function of the lower extremity to enable pain-free and stable standing and walking; however, for older patients in particular, a careful preoperative multidisciplinary planning, detailed preoperative assessment and optimization of comorbidities, such as diabetes, malnutrition or pathological vascular alterations, as well an age-adapted perioperative management are necessary. By implementing these principles, older and very old patients can maintain their mobility and autonomy, which are crucial for a high quality of life.

Long-term outcomes of perioperative myocardial infarction/injury after non-cardiac surgery.

AIMS: Perioperative myocardial infarction/injury (PMI) following non-cardiac surgery is a frequent cardiac complication. Better understanding of the underlying aetiologies and outcomes is urgently needed. METHODS AND RESULTS: Aetiologies of PMIs detected within an active surveillance and response programme were centrally adjudicated by two independent physicians based on all information obtained during clinically indicated PMI work-up including cardiac imaging among consecutive high-risk patients undergoing major non-cardiac surgery in a prospective multicentre study. PMI aetiologies were hierarchically classified into 'extra-cardiac' if caused by a primarily extra-cardiac disease such as severe sepsis or pulmonary embolism; and 'cardiac', further subtyped into type 1 myocardial infarction (T1MI), tachyarrhythmia, acute heart failure (AHF), or likely type 2 myocardial infarction (lT2MI). Major adverse cardiac events (MACEs) including acute myocardial infarction, AHF (both only from day 3 to avoid inclusion bias), life-threatening arrhythmia, and cardiovascular death as well as all-cause death were assessed during 1-year follow-up. Among 7754 patients (age 45-98 years, 45% women), PMI occurred in 1016 (13.1%). At least one MACE occurred in 684/7754 patients (8.8%) and 818/7754 patients died (10.5%) within 1 year. Outcomes differed starkly according to aetiology: in patients with extra-cardiac PMI, T1MI, tachyarrhythmia, AHF, and lT2MI 51%, 41%, 57%, 64%, and 25% had MACE, and 38%, 27%, 40%, 49%, and 17% patients died within 1 year, respectively, compared to 7% and 9% in patients without PMI. These associations persisted in multivariable analysis. CONCLUSION: At 1 year, most PMI aetiologies have unacceptably high rates of MACE and all-cause death, highlighting the urgent need for more intensive treatments. STUDY REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT02573532.

The European Bone and Joint Infection Society definition of periprosthetic joint infection is meaningful in clinical practice: a multicentric validation study with comparison with previous definitions.

BACKGROUND AND PURPOSE: A new periprosthetic joint infection (PJI) definition has recently been proposed by the European Bone and Joint Infection Society (EBJIS). The goals of this paper are to evaluate its diagnostic accuracy and compare it with previous definitions and to assess its accuracy in preoperative diagnosis. PATIENTS AND METHODS: We retrospectively evaluated a multicenter cohort of consecutive revision total hip and knee arthroplasties. Cases with minimum required diagnostic workup were classified according to EBJIS, 2018 International Consensus Meeting (ICM 2018), Infectious Diseases Society of America (IDSA), and modified 2013 Musculoskeletal Infection Society (MSIS) definitions. 2 years' minimum follow-up was required to assess clinical outcome. RESULTS: Of the 472 cases included, PJI was diagnosed in 195 (41%) cases using EBJIS; 188 (40%) cases using IDSA; 172 (36%) using ICM 2018; and 145 (31%) cases using MSIS. EBJIS defined fewer cases as intermediate (5% vs. 9%; p = 0.01) compared with ICM 2018. Specificity was determined by comparing risk of subsequent PJI after revision surgery. Infected cases were associated with higher risk of subsequent PJI in every definition. Cases classified as likely/confirmed infections using EBJIS among those classified as not infected in other definitions showed a significantly higher risk of subsequent PJI compared with concordant non-infected cases using MSIS (RR = 3, 95% CI 1-6), but not using ICM 2018 (RR = 2, CI 1-6) or IDSA (RR = 2, CI 1-5). EBJIS showed the highest agreement between pre-operative and definitive classification (k = 0.9, CI 0.8-0.9) and was better at ruling out PJI with an infection unlikely result (sensitivity 89% [84-93], negative predictive value 90% [85-93]). CONCLUSION: The newly proposed EBJIS definition emerged as the most sensitive of all major definitions. Cases classified as PJI according to the EBJIS criteria and not by other definitions seem to have increased risk of subsequent PJI compared with concordant non-infected cases. EBJIS classification is accurate in ruling out infection preoperatively.

Perioperative myocardial injury and mortality after revision surgery for orthopaedic device-related infection.

AIMS: Periprosthetic joint infections (PJIs) and fracture-related infections (FRIs) are associated with a significant risk of adverse events. However, there is a paucity of data on cardiac complications following revision surgery for PJI and FRI and how they impact overall mortality. Therefore, this study aimed to investigate the risk of perioperative myocardial injury (PMI) and mortality in this patient cohort. METHODS: We prospectively included consecutive patients at high cardiovascular risk (defined as age ≥ 45 years with pre-existing coronary, peripheral, or cerebrovascular artery disease, or any patient aged ≥ 65 years, plus a postoperative hospital stay of > 24 hours) undergoing septic or aseptic major orthopaedic surgery between July 2014 and October 2016. All patients received a systematic screening to reliably detect PMI, using serial measurements of high-sensitivity cardiac troponin T. All-cause mortality was assessed at one year. Multivariable logistic regression models were applied to compare incidence of PMI and mortality between patients undergoing septic revision surgery for PJI or FRI, and patients receiving aseptic major bone and joint surgery. RESULTS: In total, 911 consecutive patients were included. The overall perioperative myocardial injury (PMI) rate was 15.4% (n = 140). Septic revision surgery for PJI was associated with a significantly higher PMI rate (43.8% (14/32) vs 14.5% (57/393); p = 0.001) and one-year mortality rate (18.6% (6/32) vs 7.4% (29/393); p = 0.038) compared to aseptic revision or primary arthroplasty. The association with PMI persisted in multivariable analysis with an adjusted odds ratio (aOR) of 4.7 (95% confidence interval (CI) 2.1 to 10.7; p < 0.001), but was not statistically significant for one-year mortality (aOR 1.9 (95% CI 0.7 to 5.4; p = 0.240). PMI rate (15.2% (5/33) vs 14.1% (64/453)) and one-year mortality (15.2% (5/33) vs 9.1% (41/453)) after FRI revision surgery were comparable to aseptic long-bone fracture surgery. CONCLUSION: Patients undergoing revision surgery for PJI were at a risk of PMI and death compared to those undergoing aseptic arthroplasty surgery. Screening for PMI and treatment in specialized multidisciplinary units should be considered in major bone and joint infections. Cite this article: Bone Joint J 2022;104-B(6):696-702.

Patient- and procedure-related factors in the pathophysiology of perioperative myocardial infarction/injury.

BACKGROUND: Perioperative myocardial infarction/injury (PMI) is a frequent, often missed and incompletely understood complication of noncardiac surgery. The aim of this study was to evaluate whether patient- or procedure-related factors are more strongly associated to the development of PMI in patients undergoing repeated noncardiac surgery. METHODS: In this prospective observational study, patient- and procedure-related factors were evaluated for contribution to PMI using: 1) logistic regression modelling with PMI as primary endpoint, 2) evaluation of concordance of PMI occurrence in the first and the second noncardiac surgery (surgery 1 and 2). and 3) the correlation of the extent of cardiomyocyte injury quantified by high-sensitivity cardiac troponin T between surgery 1 and 2. The secondary endpoint was all-cause mortality associated with PMI reoccurrence in surgery 2. RESULTS: Among 784 patients undergoing repeated noncardiac surgery (in total 1'923 surgical procedures), 116 patients (14.8%) experienced PMI during surgery 1. Among these, PMI occurred again in surgery 2 in 35/116 (30.2%) patients. However, the vast majority of patients developing PMI during surgery 2 (96/131, 73.3%) had not developed PMI during surgery 1 (phi-coefficient 0.150, p < 0.001). The correlation between the extent of cardiomyocyte injury occurring during surgery 1 and 2 was 0.153. All-cause mortality following a second PMI in surgery 2 was dependent on time since surgery (adjusted hazard ratio 5.6 within 30 days and 2.4 within 360 days). CONCLUSIONS: In high-risk patients, procedural factors are more strongly associated with occurrence of PMI than patient factors, but patient factors are also contributors to the occurrence of PMI.

Soft-tissue reconstruction in lower-leg fracture-related infections: An orthoplastic outcome and risk factor analysis.

Introduction Fracture-related infection (FRI) is a severe post-traumatic complication which is occasionally accompanied by a deficient or even avital soft-tissue envelope. In these cases, a thoroughly planned orthoplastic approach is imperative as a vital and intact soft-tissue envelope is mandatory to achieve fracture union and infection eradication. The aim of this study was, to analyse if soft-tissue reconstruction (STR) without complications is associated with a better long-term outcome compared to FRI patients with STR complications. In particular, it was investigated if primary flap failure represented a risk factor for compromised fracture union and recurrence of infection. Patients and Methods Patients with a lower leg FRI requiring STR (local, pedicled and free flaps) who were treated from 2010-18 at the University Hospital Basel were included in this retrospective analysis. The main outcome measure was the success rate of STR, further outcome measures were fracture nonunion and recurrence of infection. Results Overall, 145 patients with lower leg FRI were identified, of whom 58 (40%) received STR (muscle flaps: n = 38, fascio-cutaneous flaps: n=19; composite osteo-cutaneous flap: n = 1). In total seven patients required secondary STR due to primary flap failure. All failures and flap-related complications occurred within the first three weeks after surgery. Secondary STR was successful in all cases. A high Charlson Comorbidity Index Score was a significant risk factor for flap failure (p = 0.011). Out of the 43 patients who completed the 9-month follow-up, 11 patients presented with fracture nonunion and 12 patients with a recurrent infection. Polymicrobial infection was a significant risk factor for fracture nonunion (p = 0.002). Primary flap failure was neither a risk factor for compromised fracture consolidation (p = 0.590) nor for recurrence of infection (p = 0.508). Conclusion: A considerable number of patients with lower-leg FRI required STR. This patient subgroup is complex and rich in complications and the long-term composite outcome demonstrated a high rate of compromised fracture consolidation and recurrent infections. It appears that secondary STR should be performed, as primary flap failure was neither a risk factor for compromised fracture consolidation nor for recurrence of infection. We propose to monitor these patients closely for three weeks after STR.

Scope and Limits of Teriparatide Use in Delayed and Nonunions: A Case Series.

Nonunion is known to occur in up to 10% of all bone fractures. Until recently, the treatment options considered in cases of delayed union and nonunion focused on revision surgery and improvement of local healing. Lately, teriparatide has been introduced as an osteoanabolic factor that induces fracture healing in cases with delayed or nonunions. We report on a series of five cases of delayed and nonunions treated with teriparatide: delayed unions of an atypical femoral fracture, of a multifragmentary clavicle fracture, and of a periprosthetic humeral fracture; nonunion of a tibial and fibular fracture; and infected nonunion of a tibial and fibular fracture. Based on this series, the indications and limits of application of teriparatide in cases of impaired fracture healing are discussed. Due to the "off-label" character of this application, informed consent, and cost coverage from the healthcare insurance must be obtained prior to treatment. In our experience and according to the limited existing literature, teriparatide is a safe feasible treatment in cases of delayed and nonunions with a reasonable need of resources. While adequate biomechanical stability remains the cornerstone of fracture healing, as well as healing of nonunions, teriparatide could help avoid repetitive surgeries, especially in atrophic delayed and nonunions, as well as in patients with impaired fracture healing undergoing bisphosphonate therapy. There is an urgent need for widely accepted definitions, standardized protocols, as well as further clinical trials in the field of impaired fracture healing.

[Periprosthetic Joint Infections - An Overview]. / Infekte in der Gelenkendoprothetik.

Periprosthetic Joint Infections - An Overview Abstract. Diagnostics and treatment of periprosthetic joint infections (PJI) is an interdisciplinary challenge. The key for success in the treatment of PJI is a rapid and adequate diagnostic and treatment in close cooperation between the general practitioner (GP), a specialised orthopaedic surgeon and an infectious disease specialist (ID). Acute PJI mostly occur peri- and early postoperative but can occur also lifelong due to haematogenous / lymphogenic seeding of the germs on the prosthesis. Both situations must be considered as an emergency scenario and patients should be transferred to the operating surgeon or even in a specialised centre for further diagnostics and treatment immediately. An acute infection (either < 4 weeks after implantation or < 3 weeks after the onset of symptoms with haematogenous / lymphogenic seeding) can frequently be cured by debridement, antibiotics and implant retention (DAIR) and should be the favoured approach in this scenario. In chronic PJI an interdisciplinary approach with complete exchange of the implant combined with an elaborated antibiotic therapy is always needed. Optimised and targeted diagnostic as well as an interdisciplinary planning of the treatment are mandatory for curing the infection, therefore patients with chronic PJI should be referred to a specialised centre. Surgery alone without adequate antibiotic therapy will mostly result in failure to cure PJI, same is true for exclusive antibiotic therapy without an adequate surgical procedure.

Orthoplastics in Periprosthetic Joint Infection of the Knee: Treatment Concept for Composite Soft-tissue Defect with Extensor Apparatus Deficiency.

Introduction: Reconstruction of composite soft-tissue defects with extensor apparatus deficiency in patients with periprosthetic joint infection (PJI) of the knee is challenging. We present a single-centre multidisciplinary orthoplastic treatment concept based on a retrospective outcome analysis over 20 years. Methods and Results: One-hundred sixty patients had PJI after total knee arthroplasty. Plastic surgical reconstruction of a concomitant perigenicular soft-tissue defect was indicated in 47 patients. Of these, six presented with extensor apparatus deficiency. One patient underwent primary arthrodesis and five patients underwent reconstruction of the extensor apparatus. The principle to reconstruct missing tissue 'like with like' was thereby favoured: Two patients with a wide soft-tissue defect received a free anterolateral thigh flap with fascia lata; one patient with a smaller soft-tissue defect received a free sensate, extended lateral arm flap with triceps tendon; and two patients who did not qualify for free flap surgery received a pedicled medial sural artery perforator gastrocnemius flap. Despite good functional results 1 year later, long-term follow-up revealed that two patients had to undergo arthrodesis because of recurrent infection and one patient was lost to follow-up. Conclusion: These results show that PJI of the knee and extensor apparatus deficiency is a dreaded combination with a poor long-term outcome. Standardization of surgical techniques for a defined PJI problem and consensus on study variables may facilitate interinstitutional comparisons of outcome data, and hence, improvement of treatment concepts.

Is cemented revision total hip arthroplasty a reasonable treatment option in an elderly population?

Revision THA is increasingly performed especially in the elderly population. The surgeon's challenge is to provide a solution that supports immediate full weight-bearing, despite poor bone quality. Shape-closed revision stems facilitate that by combining cement fixation with additional press-fit anchoring. The design tolerates varying cement mantle thickness and inconsistent cancellous bone lining of the femoral canal. Following that philosophy, we present our mid-term results using a long version of a cemented Charnley- Kerboull type stem. From 2010 to 2017, 38 long Charnley-Kerboull revision stems (Centris®, Mathys European Orthopaedics, Bettlach, Switzerland) were implanted and followed prospectively. Surgery was performed via a Hardinge approach in supine position with a third generation cementing technique. Patients were mobilized using full-weight bearing as early as possible. Survival was determined for stem revision for aseptic loosening and stem and/or cup revision for any reason. 20 stems had a minimum follow-up (f/u) of 2 years and were included for further radiological analysis. Detailed subsidence analysis as an early predictor for later aseptic loosening was performed using EBRA-FCA software. Further, the presence of osteolysis and cement debonding was evaluated. Mean follow- up was 4 years. No patient was lost to f/u.18 died of causes unrelated to THA. Stem survival was 100%. Survival for any re-operation was 82.2% (two early infections, one soft-tissue debridement, one cup exchange for recurrent dislocations). None of the cases revised for septic loosening showed signs of persistent infection at final f/u. EBRA-FCA revealed two oligosymptomatic cases of subsidence of 5mm and 6mm over a course of 2 and 12 months, respectively, with stable implants thereafter. Neither required revision. There was no development of osteolysis or debonding. The stem provides a reliable early fullweight bearing solution for revision THA with excellent mid-term survival in an elderly population. Even in two cases where subsidence was present, mobility was not impaired and re-revision could be avoided.

Five-year prospective subsidence analysis of 100 cemented polished straight stems: A concise clinical and radiological follow-up observation.

Early subsidence (>1.5mm) has been shown to be an indicator for later aseptic loosening of cemented hip stems. For the cemented twinSys® stem we published excellent short-term results at 2 years. Midterm data for this stem are available from national registers (NZL, NL), however in all of these sources, clinical and radiological results are missing. Aim of our study was to analyse mid-term survival and radiological changes around the cemented twinSys® stem with special emphasis on subsidence using EBRA-FCA. We conducted a prospective clinical and radiological 5- year follow-up study of 100 consecutive hybrid total hip arthroplasties (THA) using a polished, cemented collarless straight stem (twinSys®, Mathys AG® Bettlach, Switzerland) with a cementless monobloc pressfit cup (RM pressfit®, Mathys AG® Bettlach, Switzerland). Median age at surgery was 79 (69 to 93) years. No patient was lost to follow-up. Survival rates were calculated using the Kaplan-Meier method. Clinical (Harris Hip Score [HHS]) and radiological (cementing quality, alignment, osteolysis, debonding and cortical atrophy) outcomes and an in-depth subsidence analysis using EBRA-FCA were performed. 22 patients died in the course of follow-up unrelated to surgery, 21 stems had an incomplete radiological follow-up. 2 stems were revised, both due to an infection. The survival rate for the stem at 5 years was 98.0% (95% CI 95.3-100%). The survival rate of the stem for revision due to aseptic loosening at 5 years was 100%. The HHS improved from 53 (14-86) points preoperatively to 90 (49-100) points 5 years after surgery. Osteolysis was found in 2 stems without clinical symptoms. In 49 out of 55 patients with a complete radiological follow- up, the EBRA-FCA analysis was possible and showed an average subsidence of 0.66 (95% CI 0.46 to 0.86) mm 5 years after surgery. 10 patients showed a subsidence >1 mm, 5 of which bigger than 1.5 mm. Subsidence was independent from radiological changes and cementing quality. The cemented twinSys® stem showed excellent clinical and radiological mid-term results at five years' follow-up and seems to be a reliable implant.

Long-term results of revision total hip arthroplasty with a cemented femoral component.

INTRODUCTION: In revision total hip arthroplasty (THA), the cancellous bone is normally completely removed out of the femoral canal during stem extraction. This situation is comparable to primary THA following the shape-closed concept, with some authors advocating to remove the metaphyseal cancellous bone to enhance press-fit stability ("French paradox"). The aim of this study was to investigate the long-term outcome, regarding survival and radiological results, of a cemented straight stem when used for revision THA and to compare these results to the results of the same stem in primary THA. MATERIALS AND METHODS: 178 stem revisions performed between 01/1994 and 08/2008 using the Virtec straight stem were included. The cumulative incidence for re-revision was calculated using a competing risk model. Risk factors for re-revision of the stem were analyzed using an absolute risk regression model. Radiographs analyzed for osteolysis, debonding and subsidence had a minimum follow-up of 10 years. RESULTS: The cumulative incidence for re-revision due to aseptic loosening of the stem was 5.5% (95% CI, 2.9-10.2%) at 10 years. Aseptic loosening was associated with younger age, larger defect size and larger stem size. After a minimum 10-year follow-up, osteolysis was seen in 39 of 80 revision THA. Compared to the results in primary THA, the survival in revision THA with the same implant was inferior. CONCLUSIONS: Cemented straight stems used for revision THA showed excellent long-term results regarding survivorship and radiological outcome. This stem therefore offers a valuable and cost-effective option in revision THA.

Long-term survival of the cemented Müller CDH stem: a minimum follow-up of 10 years.

INTRODUCTION: Total hip arthroplasty in patients with altered anatomy of the hip and femur, such as in congenital dysplasia of the hip, is challenging and often requires specially designed stems. Müller straight stems have shown excellent long-term results; however, long-term data on the analogous cemented Müller CDH stem are still missing. The aim of this study was to analyze long-term survival, identify potential risk factors for aseptic loosening, and analyze radiological outcome of the cemented Müller CDH stems. MATERIALS AND METHODS: Between 01/1985 and 06/2005, 95 Müller CDH stems (Zimmer, Winterthur, Switzerland) made up of 3 different materials were cemented using 2 different bone cements: 38 of stainless steel/high-viscosity cement, 31 of a cobalt-chrome-based alloy (CoCr)/low-viscosity cement, and 26 of a titanium-based alloy (Ti)/low-viscosity cement. All patients had a prospective clinical and radiological follow-up according to the standards of our institution. The cumulative incidence for revision of the stem was calculated using a competing risk model. To identify demographic and implant-related risk factors for aseptic loosening of the stem, a multivariate regression model for competing risks was performed. RESULTS: The cumulative risk of revision at 15 years was 12.5% (95% CI 6.6-20.5%) for aseptic loosening of the stem as endpoint, with marked differences for the various stem materials used: stainless steel 2.7% (0.2-12.3%), CoCr 12.9% (4.0-27.3%), and Ti 24.5% (9.6-43.1%). Regression modeling revealed that Ti stems in combination with low-viscosity cement (HR 10.2) and implantation with an axis deviation greater than 3° (HR 3.8) are risk factors for aseptic loosening. CONCLUSIONS: Long-term survival of the cemented Müller CDH stem is comparable to other Müller-type straight stems and uncemented implants. Similar to the original Ti Müller straight stem, the Ti Müller CDH stem also showed an increased risk for aseptic loosening and should, therefore, no longer be used.

Mid-term results of revision total hip arthroplasty with an uncemented modular femoral component.

INTRODUCTION: During revision total hip arthroplasty (THA), the surgeon commonly faces deficient proximal femoral bone. In this situation, distal fixation of the prosthesis is required. The aim of the current retrospective study is to assess the clinical and radiographic mid-term outcome of revision total hip arthroplasty using a modular uncemented, tapered, grit-blasted, distal straight stem system. METHODS: This retrospective study included 70 femoral revisions that were performed in 67 patients using the device of interest. All patients were operated on via an extended trochanteric osteotomy. 60 revisions were performed as 1-stage (12 infected) and 10 as 2-stage (all infected) revisions. At 3 months postoperatively and at final follow-up, patients were assessed radiographically for the presence of osteolysis and for distal integration. RESULTS: The mean follow-up time was 4.3 (2.0-7.6) years. 4 patients had a removal of at least 1 prosthetic component. Stem survival for any reason was 92% after 5 years (95% confidence interval [CI], 83%-100%). With aseptic loosening of the stem as the endpoint of interest, survival after 5 years was 96% (95% CI, 88%-100%). A postoperative subsidence rate of 14.7% was found. No perioperative femoral fractures were found in the current patient series. CONCLUSIONS: This study showed excellent mid-term survival and good clinical and radiographic outcomes in patients who had undergone revision THA with a modular uncemented, tapered, straight design.