Systemically administered zoledronic acid activates locally implanted synthetic hydroxyapatite particles enhancing peri-implant bone formation: A regenerative medicine approach to improve fracture fixation.

Fracture fixation in an ageing population is challenging and fixation failure increases mortality and societal costs. We report a novel fracture fixation treatment by applying a hydroxyapatite (HA) based biomaterial at the bone-implant interface and biologically activating the biomaterial by systemic administration of a bisphosphonate (zoledronic acid, ZA). We first used an animal model of implant integration and applied a calcium sulphate (CaS)/HA biomaterial around a metallic screw in the tibia of osteoporotic rats. Using systemic ZA administration at 2-weeks post-surgery, we demonstrated that the implant surrounded by HA particles showed significantly higher peri­implant bone formation compared to the unaugmented implants at 6-weeks. We then evaluated the optimal timing (day 1, 3, 7 and 14) of ZA administration to achieve a robust effect on peri­implant bone formation. Using fluorescent ZA, we demonstrated that the uptake of ZA in the CaS/HA material was the highest at 3- and 7-days post-implantation and the uptake kinetics had a profound effect on the eventual peri­implant bone formation. We furthered our concept in a feasibility study on trochanteric fracture patients randomized to either CaS/HA augmentation or no augmentation followed by systemic ZA treatment. Radiographically, the CaS/HA group showed signs of increased peri­implant bone formation compared with the controls. Finally, apart from HA, we demonstrated that the concept of biologically activating a ceramic material by ZA could also be applied to ß-tricalcium phosphate. This novel approach for fracture treatment that enhances immediate and long-term fracture fixation in osteoporotic bone could potentially reduce reoperations, morbidity and mortality. STATEMENT OF SIGNIFICANCE: • Fracture fixation in an ageing population is challenging. Biomaterial-based augmentation of fracture fixation devices has been attempted but lack of satisfactory biological response limits their widespread use. • We report the biological activation of locally implanted microparticulate hydroxyapatite (HA) particles placed around an implant by systemic administration of the bisphosphonate zoledronic acid (ZA). The biological activation of HA by ZA enhances peri­implant bone formation. •Timing of ZA administration after HA implantation is critical for optimal ZA uptake and consequently determines the extent of peri­implant bone formation. • We translate the developed concept from small animal models of implant integration to a proof-of-concept clinical study on osteoporotic trochanteric fracture patients. • ZA based biological activation can also be applied to other calcium phosphate biomaterials.

Comparative effectiveness research on proximal femoral nail versus dynamic hip screw in patients with trochanteric fractures: a systematic review and meta-analysis of randomized trials.

BACKGROUND: The treatments for trochanteric fractures try to regain early mobility and limit morbidity and risk of reoperations. The most currently used dynamic hip screw (DHS) and the proximal femoral nail (PFN) are both with pros and cons. We aimed to assess the comparative effectiveness of these interventions for trochanteric fractures by evaluating the surgical performance and postoperative outcomes. METHODS: PubMed, Web of Science and Cochrane Central Register were searched for RCTs comparing DHS and PFN for trochanteric fractures. All selected studies and the risk of bias were assessed. Clinical data including operative time, intraoperative blood loss, intraoperative fluoroscopy time, successful closed reduction and complications like nonunion, implant failure and reoperation were recorded. Random-effects models were used in Review Manager software, and GRADE was applied for the interpretation of the evidence. RESULTS: From 286 identified trials, twelve RCTs including 1889 patients were eligible for inclusion; six RCTs directly comparing DHS with PFN, while other six compared DHS with proximal femoral nail antirotation (PFNA). Compared to DHS, PFN had shorter operative time and led to less intraoperative blood loss. However, DHS need less intraoperative fluoroscopy time than PFN. No difference was seen for the achievement of closed reduction. For risk of postoperative complications, no difference was seen between PFN and DHS for non-union, risk of implant failure and revision surgery. CONCLUSIONS: PFN(A) resulted in a shorter operative time and less intraoperative blood loss compared to DHS. However, no difference was seen for postoperative complications. Trial registration PROSPERO: CRD42021239974.

A New Augmentation Method for Improved Screw Fixation in Fragile Bone.

Pertrochanteric fractures (TF) due to osteoporosis constitute nearly half of all proximal femur fractures. TFs are treated with a surgical approach and fracture fixation is achieved using metallic fixation devices. Poor quality cancellous bone in osteoporotic patients makes anchorage of a fixation device challenging, which can lead to failure of the fracture fixation. Methods to reinforce the bone-implant interface using bone cement (PMMA) and other calcium phosphate cements in TFs have been described earlier but a clear evidence on the advantage of using such biomaterials for augmentation is weak. Furthermore, there is no standardized technique for delivering these biomaterials at the bone-implant interface. In this study, we firstly describe a method to deliver a calcium sulphate/hydroxyapatite (CaS/HA) based biomaterial for the augmentation of a lag-screw commonly used for TF fixation. We then used an osteoporotic Sawbones model to study the consequence of CaS/HA augmentation on the immediate mechanical anchorage of the lag-screw to osteoporotic bone. Finally, as a proof-of-concept, the method of delivering the CaS/HA biomaterial at the bone-implant interface as well as spreading of the CaS/HA material at this interface was tested in patients undergoing treatment for TF as well as in donated femoral heads. The mechanical testing results indicated that the CaS/HA based biomaterial increased the peak extraction force of the lag-screw by 4 times compared with un-augmented lag-screws and the results were at par with PMMA. The X-ray images from the patient series showed that it was possible to inject the CaS/HA material at the bone-implant interface without applying additional pressure and the CaS/HA material spreading was observed at the interface of the lag-screw threads and the bone. Finally, the spreading of the CaS/HA material was also verified on donated femoral heads and micro-CT imaging indicated that the entire length of the lag-screw threads was covered with the CaS/HA biomaterial. In conclusion, we present a novel method for augmenting a lag-screw in TFs, which could potentially reduce the risk of fracture fixation failure and reoperation in fragile osteoporotic patients.

A combined fracture and mortality risk index useful for treatment stratification in hip fragility fractures.

OBJECTIVES: In this study, we aimed to assess the stratification ability of the Fracture and Mortality Risk Evaluation (FAME) index for reoperation, new fragility fracture, and mortality during one-year follow-up. PATIENTS AND METHODS: Between November 2018 and July 2019, a total of 94 consecutive hip fragility fracture patients from two centers (20 males, 74 females; mean age: 79.3±8.9 years; range, 57 to 100 years) were retrospectively analyzed. The patients were classified into high, intermediate, and low fracture and mortality risk groups according to the Fracture Risk Assessment Tool (FRAX) score and Sernbo score, respectively, as well as nine combined categories according to the FAME index. Hospital records were reviewed to identify re-fractures (reoperations, implant failure, new fragility fractures on any site) and mortality at one year following the FAME index classification. RESULTS: Overall re-fracture and mortality rates were 20.2% and 33%, respectively. High fracture risk category (FRAX-H) was significantly associated with higher re-fracture (odds ratio [OR]: 2.9, 95% confidence interval [CI]: 1-8.2, p=0.037) and mortality rates compared to others (OR: 3.7, 95% CI: 1.5-9.3, p=0.003). The patients classified within the FRAX-H category (n=35) had different mortality rates according to their Sernbo classification; i.e., patients classified as low mortality risk (Sernbo-L) (n=17) had lower mortality rates compared to others in this group (n=18) (35.3% and 66.7%, respectively), indicating a low statistical significance (OR: 0.3, 95% CI: 0.1-1.1, p=0.063). Similarly, within patients classified in Sernbo-L category (n=64), those classified as high fracture risk (FRAX-H) (n=17) had significantly higher re-fracture rates compared to others in this group (n=47) (35.3% and 8.5%, respectively), (OR: 5.9; 95% CI: 1.4-24.5), (p=0.017). Multivariate logistic regression analyses adjusting for covariates (age, sex, length of hospital stay and BMI) yielded similar results. CONCLUSION: The FAME index appears to be a useful stratification tool for allocating patients in a randomized-controlled trial for augmentation of hip fragility fractures.

Comparison of 2 Peripheral Nerve Blocks Techniques for Functional Recovery and Postoperative Pain Management After Total Knee Arthroplasty: A Prospective, Double-Blinded, Randomized Trial.

BACKGROUND Methods of pain management that have less effect on motor function after total knee arthroplasty (TKA) are needed to ensure early mobilization. We investigated whether the distal femoral triangle and distal adductor canal blocks are superior to the femoral nerve block regarding motor blockade at early postoperative hours. MATERIAL AND METHODS Patients scheduled for TKA under spinal anesthesia were blindly assigned into 2 groups. One group received the distal femoral triangle and distal adductor canal blocks and the other group received the femoral nerve block. In both groups, at 3, 6, 24, and 48 h after surgery motor blockade was evaluated with the Bromage scale. Secondary outcomes such as pain control efficacy and patient satisfaction were evaluated at 6, 24, and 48 h postoperatively using either the VAS scale or a 10-point scale. RESULTS We analyzed the outcomes of 77 patients. Better motor function at 3 and 6 h after TKA was observed in the distal femoral triangle and the distal adductor canal blocks group (37.7% vs 23.4%, p=0.032 and 49.4% vs 32.5%, p=0.002, respectively). At 24 h after the surgery, patients from the femoral nerve block group consumed significantly more rescue opioid analgesics (p=0.016). We found no significant differences in pain intensity and patient satisfaction at any timepoints after the surgery. CONCLUSIONS The distal femoral triangle and distal adductor canal blocks resulted in significantly better motor function at the first 3 and 6 h after total knee arthroplasty. At 24 h after surgery, rescue opioid doses in the femoral nerve block group were significantly higher.

Different microbial and resistance patterns in primary total knee arthroplasty infections - a report on 283 patients from Lithuania and Sweden.

BACKGROUND: The microbiology and the susceptibility patterns of infected total knee arthroplasties (TKAs) vary depending on demographic, local antimicrobial stewardship, and surgical factors. We wanted to compare the recent microbial profile and antimicrobial resistance pattern in revisions due to infections after primary TKAs in Sweden and Lithuania. Our hypothesis was that there is a difference in bacteriology and resistance pattern based on patient related, societal and local hospital factors as almost similar praxis have been applied for TKA surgery, short term systemic prophylaxis and routine use of local gentamicin containing bone cement. METHODS: Primary TKAs revised for the first time due to verified or suspected infection were collected nationwide in Sweden during 2018, and in Lithuania between 2011 and 2020 from a single major TKA revision centre in Kaunas. We identified 202 TKAs in Sweden from the Swedish Knee Arthroplasty Register and 84 from Kaunas revised due to infection. We collected available culture reports and evaluated the type of microorganisms with antimicrobial resistance pattern at revision. RESULTS: The majority of the infected cases in Sweden were early-type prosthetic joint infection (PJI) (44%), whereas late-type PJI (52%) were more common in the Kaunas cases. Gram-positive bacteria prevailed in both Sweden (55%) and Lithuania (80%). Staphylococcus aureus was the most frequent organism identified in both countries (33% in Sweden and 34% in Lithuania). More polymicrobial infections were observed in Sweden than in Lithuania (16 and 6% respectively). Methicillin resistance in Staphylococcus aureus and coagulase-negative staphylococci were higher in Lithuania (4/28 and 19/29) than in Sweden (1/42 and 9/41). CONCLUSIONS: The type of infections, microbial profile, and drug resistance pattern differed between Sweden and Lithuania. Societal and local hospitals factors with emerging resistance in Lithuania are the most plausible explanation for the difference. Lack of complete data on a national level in Lithuania underlines the importance of adding microbiology of PJIs in implant registers for national aggregation and allow cross country comparisons.

Augmenting a dynamic hip screw with a calcium sulfate/hydroxyapatite biomaterial.

Internal fixation failure in hip fractures can lead to reoperation. Calcium sulfate/hydroxyapatite (CaS/HA) is a biomaterial that can be used for augmenting fracture fixation. We aimed to determine whether an injection of 2 ml CaS/HA increases the fixation of a dynamic hip screw inserted in synthetic and human trabecular bone. The study consists of two parts: 1) synthetic bone blocks (n = 74), with three subgroups: empty (cannulated screw, no injection), cannulated, and fenestrated; and 2) osteoporotic human femoral heads (n = 29), with the same subgroups. The heads were imaged using µCT. Bone volume fraction, insertion angle, and head diameter were measured. Pullout tests were performed and peak force, stiffness, and work were measured. The fenestrated group showed increases in pullout strength compared to no injection in the synthetic blocks. The cannulated group showed a higher pullout strength in low-density blocks. In the femoral heads, the variation was larger and there were no significant differences between groups. The bone volume fraction correlated with the peak force and work, and the insertion angle correlated with the stiffness. CaS/HA can improve the fixation of a dynamic hip screw. For clinical use, spreading of the material around the threads of the screw must be ensured.

Bipolar hemiarthroplasty versus total hip arthroplasty in femoral neck fracture patients: results from Lithuanian Arthroplasty Register.

INTRODUCTION: Elderly patients with displaced femoral neck fractures (FNF) are usually operated with arthroplasty but with various combinations of implants and approaches. Thus, the optimal treatment is still controversial. We aimed to compare the results between the cemented bipolar hemiarthroplasty (HA) and total hip arthroplasty (THA) patients operated for FNF regarding revision rate at 1 year postoperatively. METHODS: The data were derived from the Lithuanian Arthroplasty Register. We included patients operated with cemented bipolar HA and compared them to the most frequently used cemented THA with 28-mm head during 2011-2016. For survival analysis, we used both revision for all reasons and for dislocations as an endpoint. Cox proportional hazards models were used to analyse the influence of covariates (age groups, gender, surgical approaches and arthroplasty groups). RESULTS: There were 1177 bipolar HA and 514 THA included in our study. 26 (2.2%) revisions had occurred among the bipolar HAs as compared to 25 (4.9%) among the THAs 1 year after surgery. The main reason for revision was dislocation. The unadjusted cumulative revision rate for any reason at 1 year after surgery was 2.4% for the bipolar HA group and 5.1% for the THA group (p = 0.0054). Cox regression analysis showed that the use of bipolar HA, anterolateral approach and younger age groups had lower risk of revision for all reasons. CONCLUSION: Bipolar HA and anterolateral approach had a significantly lower overall 1-year risk of revision in femoral neck fracture patients as compared to THA with 28-mm femoral heads.

Combined fracture and mortality risk evaluation for stratifying treatment in hip fracture patients: A feasibility study.

OBJECTIVES: This study aims to test the feasibility of the Fracture and Mortality Risk Evaluation (FAME) Index. PATIENTS AND METHODS: Two academic centers in Lithuania and Turkey participated in this retrospective study conducted between November 2018 and July 2019. A total of 100 consecutive patients (22 males, 78 females; mean age 78.9 years; range, 45 to 100 years) with low energy proximal femur fractures admitted for surgery were included in the study. Fracture Risk Assessment tool (FRAX) and the Sernbo scores were calculated and patients were classified into one of the nine subcategories of the FAME Index. RESULTS: Demographics and FAME Index classifications were similar between centers. Patients with high risk of fracture and low risk of mortality accounted for 18% of all patients, which is the FAME Index subcategory to theoretically benefit from cancellous bone augmentation during internal fixation of a fragility hip fracture the most. CONCLUSION: The FAME Index was successfully applied in clinical emergency setting utilizing a simple form, and demonstrated promising potential in stratification of hip fractures most suitable for screw and device augmentation. Larger studies with at least one-year of follow-up are warranted to verify the validity of FAME Index.

Long-Term Response to a Bioactive Biphasic Biomaterial in the Femoral Neck of Osteoporotic Rats.

Osteoporosis often leads to fragility fractures of the hip, resulting in impaired quality of life and increased mortality. Augmenting the proximal femur could be an attractive option for prevention of fracture or fixation device failure. We describe a tissue engineering based strategy to enhance long-term bone formation in the femoral neck of osteoporotic rats by locally delivering bioactive molecules; recombinant human bone morphogenic protein-2 (rhBMP-2), and zoledronic acid (ZA) by using a calcium sulfate/hydroxyapatite (CaS/HA) biomaterial. A defect was created by reaming the femoral neck canal of osteoporotic (OVX) rats and they were treated as follows: G1. Empty, G2. CaS/HA, G3. CaS/HA+Systemic ZA, G4. CaS/HA+Local ZA, and G5. CaS/HA+Local ZA+rhBMP-2. Bone formation was evaluated 6 months after treatment. Further, radioactively labeled 14C-ZA was used to study the bioavailability of ZA at the defect location, which was determined by using scintillation counting. Micro-CT indicated significantly higher bone volume in groups G4 and G5 compared with the other treatment groups. This was confirmed qualitatively by histological assessment. Addition of rhBMP-2 gave no additional benefit in this model. Local delivery of ZA performed better than systemic administration of ZA. Mechanical testing showed no differences between the groups, likely reflecting that the addition of bioactive molecules had limited effect on cortical bone or the choice of mechanical testing setup was not optimal. Scintillation counting revealed higher amounts of 14C-ZA present in the treated leg of G4 compared with its contralateral control and compared with G3, indicating that local ZA delivery can be used to achieve high local concentrations without causing a systemic effect. This long-term study shows that local delivery of ZA using a CaS/HA carrier can regenerate cancellous bone in the femoral neck canal and has clear implications for enhancing implant integration and fixation in fragile bone.

Inadequate evaluation and management of suspected -infections after TKA surgery in Lithuania: a retrospective study of 2,769 patients with 2-year follow-up.

Background and purpose - The evidence-based algorithms for treatment of periprosthetic joint infection (PJI) recommend surgical intervention in combination with the use of systemic antibiotics. However, still it is not unusual to treat total knee arthroplasty (TKA) patients with suspected infection using only antibiotics. We investigated treatment pathways for TKA patients with suspected infection in Lithuania. Patients and methods - Of the 4,069 TKA patients (4,269 knees) registered in the Lithuanian Arthroplasty Register (2013-2015) 2,769 patients (2,825 knees) were interviewed 2 years after the surgery. The patients were asked if they had been subject to antibiotic treatment after the TKA surgery and/or if any additional surgical interventions on the operated knee had been performed. The number of patients treated with antibiotics due to problems in the operated knee was identified and cumulative revision rates (CRR) were calculated. Results - 180 (7%) patients of the total 2,769 reported that they had been prescribed antibiotics after the primary TKA; 132 of these patients (70%) said they had received antibiotics due to problems with the operated knee. The 2-year CRR after TKA in patients not treated with antibiotics was 0.7% (95% CI 0.4-1), as compared with 24% (95% CI 17-32) in those who had used antibiotics due to the problems in the operated knee for more than 1 week. Interpretation - In Lithuania there seems to be a lack of adherence to evidence-based treatment guidelines when infection is suspected after primary TKA.

Fracture strength of the proximal femur injected with a calcium sulfate/hydroxyapatite bone substitute.

BACKGROUND: Available interventions for preventing fragility hip fractures show limited efficacy. Injection of a biomaterial as bone substitute could increase the fracture strength of the hip. This study aimed to show the feasibility of injecting a calcium sulfate/hydroxyapatite based biomaterial in the femoral neck and to calculate the consequent change in strength using the finite element method. METHODS: Five patients were injected with 10 ml calcium sulfate/hydroxyapatite in their femoral neck. Quantitative CT scans were taken before and after injection. Five additional patients with fragility hip fractures were also scanned and the images from the non-fractured contralateral sides were used. Finite element models were created for all proximal femora with and without injection and the models were tested under stance and sideways fall loading until fracture. The change in fracture strength caused by the injection was calculated. Additionally, perturbations in volume, location, and stiffness of the injected material were created to investigate their contribution to the fracture strength increase. FINDINGS: The 10 ml injection succeeded in all patients. Baseline simulations showed theoretical fracture strength increases of 0-9%. Volume increase, change in location and increase in stiffness of the material led to increases in fracture strength of 1-27%, -8-26% and 0-17%, respectively. Altering the location of the injection to a more lateral position and increasing the stiffness of the material led to increases in fracture strength of up to 42%. INTERPRETATION: This study shows that an injection of calcium sulfate/hydroxyapatite is feasible and can theoretically increase the hip's fracture strength.

A ceramic bone substitute containing gentamicin gives good outcome in trochanteric hip fractures treated with dynamic hip screw and in revision of total hip arthroplasty: a case series.

BACKGROUND: The primary objective was to investigate the clinical and radiological outcome in patients undergoing major hip surgery using a novel antibiotic containing bone substitute for local augmentation in trochanteric fracture fixation or revision of total hip arthroplasty (THA). METHODS: We implanted a novel biphasic bone substitute CERAMENT™|G consisting of hydroxyapatite, calcium sulphate and gentamicin for bone regeneration and local antibiotic delivery in 20 patients treated surgically for trochanteric femoral fracture or uncemented hip revision. Preoperative, postoperative, 3 months and 1 year clinical and radiological assessment were performed including registration of any complications. In one trochanteric fracture patient, histological analyses were performed of bone biopsies taken at removal of hardware. RESULTS: None of the trochanteric fractures or revision of THA showed any large migration. No local wound disturbances were seen and no infection was observed at one year follow-up. All trochanteric fractures healed at 3 months with a minimal sliding screw displacement on average 3 mm. Radiological analysis showed signs of bone remodeling and new bone formation in the substitute, illustrated also by histology in the biopsies taken from one trochanteric fracture at one year post-op. CONCLUSIONS: Local CERAMENT™|G was shown to be safe in a limited prospective major hip surgery study. Remodeling of the bone graft substitute was observed in all patients. TRIAL REGISTRATION: EU-CTR2018-004414-18 Retrospectively registered on November 20, 2018.

Outcomes and mortality after hip fractures treated in Kazakhstan.

INTRODUCTION: Patients with hip fractures are usually treated operatively in Western Europe. However, in Mid-Asia different indications are used to decide whether this patient is suitable for operative treatment and those are related to specific traditions and rules in hospital. Thus, traditions and surgeon/patient fears seem to affect treatment choices in hip fractures and subsequent outcomes. The aim of our study was to investigate patients with hip fractures and compare outcome at 1-year follow-up in the operated and nonoperated patient groups. METHODS: All patients over 50 years old who sustained a hip fracture, between January 2014 and December 2014, were included. Patients were assessed preoperatively and at 1-year follow-up, using questionnaires from National Swedish Hip Fracture Register and quality of life (Euroqol EQ-5D). RESULTS: Out of 398 included patients, 299 were operated on and 99 were not. 344 patients remained for our analysis before the end of 1-year follow-up. 51 patients (65%) deceased in the nonoperated group as compared to 55 (21%) in the operated group, p<0.001. Out of 27 patients in the nonoperated group hip function was evaluated at 1-year follow-up, 11 (41%) were walking independently or using 1 stick, as compared to 192 (91%) in the operated group. CONCLUSIONS: We conclude that nonoperative treatment of hip fracture patients is associated with higher mortality and worse functional outcome as compared to those who were treated operatively. We therefore advocate operative treatment of the hip fracture in the vast majority of cases.

Calcium Sulphate/Hydroxyapatite Carrier for Bone Formation in the Femoral Neck of Osteoporotic Rats.

This study investigated bone regeneration in the femoral neck canal of osteoporotic rats using a novel animal model. A calcium sulphate (CS)/hydroxyapatite (HA) carrier was used to deliver a bisphosphonate, zoledronic acid (ZA), locally, with or without added recombinant human bone morphogenic protein-2 (rhBMP-2). Twenty-eight-week-old ovariectomized Sprague-Dawley rats were used. A 1 mm diameter and 8 mm long defect was created in the femoral neck by drilling from the lateral cortex in the axis of the femoral neck, leaving the surrounding cortex intact. Three treatment groups and one control group were used: (1) CS/HA alone, (2) CS/HA + ZA (10 µg) (3) CS/HA + ZA (10 µg) + rhBMP-2 (4 µg), and (4) empty defect (control). The bone formation was assessed at 4 weeks post surgery using in vivo micro computed tomography (micro-CT). At 8 weeks post surgery, the animals were sacrificed, and both defect and contralateral femurs were subjected to micro-CT, mechanical testing, and histology. Micro-CT results showed that the combination of CS/HA with ZA or ZA + rhBMP-2 increased the bone formation in the defect when compared to the other groups and to the contralateral hips. Evidence of new dense bone formation in CS/HA + ZA and CS/HA + ZA + rhBMP-2 groups was seen histologically. Mechanical testing results showed no differences in the load to fracture between the treatments in either of the treated or contralateral legs. The CS/HA biomaterial can be used as a carrier for ZA and rhBMP-2 to regenerate bone in the femoral neck canal of osteoporotic rats.

Antibiotic Containing Bone Substitute in Major Hip Surgery: A Long Term Gentamicin Elution Study.

Objectives: The objective is to present the antibiotic elution from a locally implanted gentamicin containing hydroxyapatite and calcium sulphate bone substitute with an extended follow up of 30 days. We also compare the pharmacokinetics of the ceramic bone substitute with a published study on gentamicin containing poly (methyl methacrylate) (PMMA) bone cement used in primary total hip arthroplasty. Methods: Gentamicin release was measured in the urine for a month and the serum for 4 days in 10 patients operated for trochanteric hip fractures and 10 patients in uncemented hip revisions. 17 patients were followed up at one year and 3 patients at 6 months. Results and Discussion: The gentamicin concentrations measured in serum were low and approximately 100 times less than in urine during the first days, indicating high local concentrations at the implant site. The elution from the biphasic bone substitute showed a stronger burst and higher gentamicin concentrations for the first week compared to that reported for PMMA used in hip arthroplasty. Also, for the bone substitute a complete gentamicin elution was obtained after 30 days, while for the PMMA cement sub-inhibitory MIC levels of gentamicin were still present in urine 60 days past surgery. No infections were detected. Conclusions: A new biphasic bone substitute containing antibiotics could potentially be used to prevent infection in patients treated for trochanteric hip fractures or uncemented hip revisions. The gentamicin elution from the bone substitute is efficient with high initial local gentamicin concentrations and complete release at 30 days.

Comparison of dual mobility cup and other surgical construts used for three hundred and sixty two first time hip revisions due to recurrent dislocations: five year results from Lithuanian arthroplasty register.

PURPOSE: Recently, there has been increasing interest in the use of dual mobility systems in the treatment of hip instability. The aim of this study was to investigate the re-revision rate of dual mobility cup compared to different surgical concepts when used for first-time hip revisions due to recurrent dislocations. METHODS: The data were derived from the Lithuanian Arthroplasty Register. For survival analysis, we used both re-revision for all reasons and for dislocations as an end-point. Cox proportional hazards models were used to analyze the influence of various covariates (age, gender, and implant concept). RESULTS: A total of 1388 revisions were recorded from 2011 to 2015, of which 362 were performed due to recurrent dislocation. Of the revisions, 247 were performed using dual mobility cups, while 115 were performed using a variety of other surgical constructs including constrained acetabular cups, conventional cups, femoral head exchanges, stem exchanges or anti-luxation rings. There were 27 re-revisions of which 15 were for additional dislocations. There were only 2% re-revisions due to dislocation with dual mobility vs 9% when using other surgical constructs. Cox regression adjusting for age and gender showed that in the short-term, dual mobility cup had a lower risk of revision due to dislocation as well as for all reasons compared to the other surgical constructs. CONCLUSION: In revision of total hip arthroplasties for dislocation, significantly lower short-term re-revision rate was observed for patients revised with dual mobility cup.

Outcomes and mortality after hip fractures treated in Kazakhstan.

INTRODUCTION: Patients with hip fractures are usually treated operatively in Western Europe. However, in Mid-Asia different indications are used to decide whether this patient is suitable for operative treatment and those are related to specific traditions and rules in hospital. Thus, traditions and surgeon/patient fears seem to affect treatment choices in hip fractures and subsequent outcomes. The aim of our study was to investigate patients with hip fractures and compare outcome at 1-year follow-up in the operated and nonoperated patient groups. METHODS: All patients over 50 years old who sustained a hip fracture, between January 2014 and December 2014, were included. Patients were assessed preoperatively and at 1-year follow-up, using questionnaires from National Swedish Hip Fracture Register and quality of life (Euroqol EQ-5D). RESULTS: Out of 398 included patients, 299 were operated on and 99 were not. 344 patients remained for our analysis before the end of 1-year follow-up. 51 patients (65%) deceased in the nonoperated group as compared to 55 (21%) in the operated group, p<0.001. Out of 27 patients in the nonoperated group hip function was evaluated at 1-year follow-up, 11 (41%) were walking independently or using 1 stick, as compared to 192 (91%) in the operated group. CONCLUSIONS: We conclude that nonoperative treatment of hip fracture patients is associated with higher mortality and worse functional outcome as compared to those who were treated operatively. We therefore advocate operative treatment of the hip fracture in the vast majority of cases.

Short-term outcome after total hip arthroplasty using dual-mobility cup: report from Lithuanian Arthroplasty Register.

PURPOSE: The purpose of the study was to investigate how the use of dual-mobility cups (DMCs) affected the risk of revision due to dislocation as well as overall risk of revision compared with a conventional total hip arthroplasty (THA) system in the short term. METHODS: A total of 12,657 primary THAs were registered from the start of 2011 to the end of 2014. 620 THAs were with DMCs. For comparison, we included all registered THAs with Exeter cup and a cemented Exeter stem combined with 28-mm femoral head. Patients were followed up with respect to revision and/or death until 1 January 2016. For survival analysis, we used revision as an endpoint. Cox proportional hazards models were used to analyse the influence of various covariates (age, gender, surgical approach, THA model and pre-operative diagnosis). RESULTS: Of the 620 dual-mobility THAs and 2170 Exeter THAs, 100 had been revised. The overall unadjusted cumulative revision rate (CRR) for any reason of revision at five years after surgery was 3.9% in the dual-mobility group and 5.2% in the Exeter group. Cox regression analysis, adjusting for age, gender, THA type, surgical approach and pre-operative diagnosis, showed that the risk of revision was less in patients operated with DMCs and in patients having their operation for osteoarthritis. CONCLUSION: The DM implant had a lower short-term complication rate than a conventional well defined THA. Low dislocation rate suggests that it is a good choice for high risk patients.

Measuring long radiographs affects the positioning of femoral components in total knee arthroplasty: a randomized controlled trial.

INTRODUCTION: The aim of this study was to investigate if preoperative measurements of the femoral valgus angle (FVA) affected the mechanical alignment, individual component positions and clinical outcome in total knee arthroplasty (TKA). METHODS: 120 patients were randomized into two groups. In one group (control), a fixed FVA for the intramedullary femoral guide was set at 7°, whereas in the other group (measured) FVA was measured preoperatively on long hip-knee-ankle radiographs, and the angle for the distal femoral cut was set accordingly. Preoperatively and 1 year after TKA, range of motion (ROM) and Knee Society Score (KSS) were assessed. Postoperatively, the coronal alignments of the components and the mechanical alignment were measured comparing the rate of outliers which deviated more than 3° from the neutral mechanical axis. RESULTS: 104 patients remained for the radiological analysis (52 in each group). There were no significant differences either in the mean preoperative or postoperative mechanical alignment, or femoral or tibial component alignment; also, there were no differences in the number of postoperative mechanical axis or tibial component alignment outliers. However, the number of femoral component alignment outliers was significantly higher in the control group. 97 patients were available for clinical outcome analysis. Preoperatively, the groups did not differ significantly with respect to KSS or ROM. The postoperative ROM and KSS functional subscale scores were similar between the groups. However, there was slightly but significantly better postoperative KSS objective subscale score in the measured group. CONCLUSIONS: Preoperative FVA measurement and following femoral distal cut adjustments did not affect overall leg alignment postoperatively, while positioning of femoral component was improved together with minor improvements in objective KSS subscale scores.