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.

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.

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.

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.

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.

Excellent long-term results of the Müller acetabular reinforcement ring in primary total hip arthroplasty: A prospective study on radiology and survival of 321 hips with a mean follow-up of 11 years.

BACKGROUND AND PURPOSE: The original Müller acetabular reinforcement ring (ARR) shows favorable medium-term results for acetabular reconstruction in total hip arthroplasty, where it is used when the acetabular bone stock is deficient. However, there are no data regarding long-term survival of the device. We therefore investigated long-term survival and analyzed radiological modes of failure. PATIENTS AND METHODS: Between 1984 and 2002, 321 consecutive primary arthroplasties using an ARR were performed in 291 patients. The mean follow-up time was 11 (0-25) years, and 24 hips were lost to follow-up. For survival analysis, we investigated 321 hips and the end of the follow-up was the date of revision, date of death, or the last patient contact date with implant still in situ. Radiological assessment was performed for 160 hips with a minimum of 10 years of follow-up and with radiographs of sufficient quality. It included evaluation of osteolysis, migration, and loosening. RESULTS: 12 ARR THAs were revised: 1 isolated ARR revision for aseptic loosening, 4 revisions of the ARR and the stem for aseptic loosening, 6 for infection, and 1 for recurrent dislocation. The cumulative revision rate for all components, for any reason, at 20 years was 15% (95% CI: 10-22), while for the ARR only it was 7% (95% CI: 4-12) for any reason and 3.4% (95% CI: 1-9) for aseptic loosening. 21 (13%) of 160 ARR THAs examined had radiological changes: 7 had osteolysis but were not loose, and 14 were radiologically loose but were not painful and not revised. INTERPRETATION: Our data suggest that the long-term survival of the ARR is excellent.

Choice of approach, but not femoral head size, affects revision rate due to dislocations in THA after femoral neck fracture: results from the Lithuanian Arthroplasty Register.

PURPOSE: Hip dislocation after arthroplasty for femoral neck fractures (FNF) remains a serious complication. The aim of our study was to investigate FNF patients treated with THA, with a special focus of comparing the effect of surgical approach and femoral head size on the risk of revision for dislocation. METHODS: Data were derived from the Lithuanian Arthroplasty Register, and we calculated the cumulative revision rates after surgery. For survival analysis, we used revision due to dislocation as an end-point. Cox proportional hazards models were used to analyse the influence of various covariates (age, gender, femoral head size, surgical approach). RESULTS: A total of 8,813 primary THAs were registered from 1 January 2011 to 31 December 2013, of which 1,412 were due to FNF: 899 involved 28-mm femoral heads and the remaining 513 received 32-mm heads. The posterior approach was used in 1,156 cases and the anterolateral approach in 256.. At the end of the follow-up period, 74 hips had been revised for recurrent dislocation. Cox regression adjusting for age, gender and head size showed that the posterior approach had 2.3-times [95% confidence interval (CI): 1.0-5.0, p = 0.04] greater risk of revision for dislocation CONCLUSIONS: We conclude that in order to reduce the early dislocation rate in FNF patients treated with THA, it is more effective to use the anterolateral approach than it is to select a femoral head size of 32 mm instead of 28 mm.

Moderate varus/valgus malalignment after total knee arthroplasty has little effect on knee function or muscle strength.

BACKGROUND AND PURPOSE: Postoperative muscle strength and component alignment are important factors affecting functional results after total knee arthroplasty (TKA). We are not aware of any studies that have investigated the relationship between them. We therefore investigated whether coronal malalignment of the mechanical axis and/or of individual implant components would affect knee muscle strength and function 1 year after TKA surgery. PATIENTS AND METHODS: We included 120 consecutive osteoarthritis (OA) patients admitted for TKA. Preoperative active range of motion (ROM) of the knee, patient age, sex, and BMI were recorded and the Knee Society score (KSS) and knee joint extensor/flexor muscle strength were assessed. At 1-year follow-up, the mechanical and coronal component alignment was measured from a postoperative long standing radiograph, and ROM, KSS, and muscle strength measurements were taken in 91 patients. Functional outcome and muscle strength measurements were compared between normally aligned and malaligned TKA groups. RESULTS: 29 of 91 TKAs were malaligned, i.e. they deviated more than 3° from the neutral mechanical axis. 18 femoral components and 15 tibial components were malaligned. Before surgery, the malaligned and normally aligned groups were similar regarding sex distribution, BMI, ROM, KSS, and muscle strength. At the 1-year follow-up, the differences between the groups regarding knee joint function and muscle strength were small, not statistically significant, and barely clinically relevant. INTERPRETATION: Moderate varus/valgus malalignment of the mechanical axis or of individual components has no relevant clinical effect on function or muscle strength 1 year after TKA surgery.

Size of cup affects the anterior capsular distance in total hip arthroplasty, as measured with ultrasound.

BACKGROUND: Previously was found that sonography is a reliable method to measure a capsular distance in total hip arthroplasty hips. The aim of our current study was to investigate the relation between the implanted size of the cup and the anterior capsular distance, as measured with ultrasound one year after THA. METHODS: 50 osteoarthritis (OA) patients operated on with total hip arthroplasty one year before were included in the study and the anterior capsular distance was measured sonographically. Patients were grouped with respect to cup size. The correlation between the implanted cup size and capsular distance was determined. RESULTS: The mean capsular distance in the whole group was 1.37 (SD 0.19) cm. The mean capsular distance in the group with small cups was 1.27 (SD 0.13) cm, in large cups it was 1.45 (SD 0.20) cm, p = 0.02. Spearman correlation analysis showed a statistically significant correlation between a greater capsular distance and the larger size of the cup (r = 0.5, p < 0.0001). CONCLUSION: The greater capsular distance in successful THA hips is affected by cup size. We propose that this should be considered when evaluating sonography of the anterior capsular distance after THA.

First outcome results after total knee and hip replacement from the Lithuanian arthroplasty register.

BACKGROUND AND OBJECTIVE: In 2010, the Lithuanian Association of Arhtroplasty was established and on January 1, 2011, initiated a national study of all reoperations after total knee (TKR) and total hip replacement (THR) in Lithuania. The aim of the study was to investigate the revision rates after TKR and THR at two years follow-up. MATERIALS AND METHODS: Lithuanian patients undergoing primary TKR and THR from January 1, 2011, to December 31, 2012, were included in the study. The patient, surgery and prosthetic implantation data were collected via internet database. For reoperations we recorded the reason and type of revision, primary implantation date. We analyzed implant survival rates using any revision as an endpoint on included primary procedures, performed until September 1, 2013. RESULTS: The completeness of the register verified with state patients fund data reached 85% of all replacements. Out of 3823 primary TKR during the study period 25 revisions were performed with overall implant survival rate 99%. The main reason for knee revision was infections. During the inclusion period we registered 6072 primary THR and 149 revisions with overall implant survival rate 97%. Recurrent dislocation of prosthetic component was the main reason for hip revision. Significantly inferior survival results for femoral neck fracture patients were observed as compared with patients operated for osteoarthritis. Posterior approach as compared to others significantly affected inferior implant survival rates for femoral neck fracture patients. CONCLUSIONS: The overall survival after total knee and hip replacements revealed a high treatment quality of this surgery in Lithuania.

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.

Associations between the fracture type and functional outcomes after distal radial fractures treated with a volar locking plate.

OBJECTIVE. The aim of this study to investigate the associations of fracture type, age, and gender with hand function after distal radius fractures treated with a volar locking plate at a 6-month follow-up. MATERIAL AND METHODS. A total of 120 patients with displaced distal radius fractures were included into the study. They were operated on using a volar locking plate system. All the fractures were classified according to the AO classification, and the patients were divided into 3 groups by the fracture type. The range of motion and grip strength were evaluated at the 6-month follow-up. Multivariate linear regression analysis was used to evaluate the associations of age, gender, and fracture type with the score of the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire. The DASH questionnaire was completed as an outcome measure. RESULTS. A total of 28 patients experienced type A fractures; 70 patients, type B fractures; and 22 patients, type C fractures. No statistically significant difference regarding age and sex among the groups was observed. At 6 months after the surgery, the mean DASH score for type A, B, and C fractures was 16, 13, and 32, respectively (P=0.01). After the surgery, the radiographic parameters such as the volar tilt and the ulnar variance were significantly worse in the patients with type C fractures. Grip strength and the range of motion of the contralateral healthy hand at the 6-month follow-up were significantly better than those of the operated hand. The linear regression analysis showed that the type C fracture was the only factor significantly associated with lower DASH score. CONCLUSIONS. The patients with type C fractures treated with a volar locking plate had a worse wrist function as compared with the patients type A and B fractures at the 6-month follow-up. The postoperative hand function was significantly associated only with the type C fracture, while age and gender had no significant impact.

Long-term femoral bone remodeling after cemented hip arthroplasty with the Müller straight stem in the operated and nonoperated femora.

We investigated the cortical bone changes in 35 patients with total hip arthroplasty operated on only for osteoarthritis with more than 10 years of follow-up and with nonrevised femoral components and without radiologic signs of loosening. The mean follow-up was 16 ± 5 years. The thicknesses of femoral cortices were measured medially and laterally at 6 levels from the first postoperative and the last follow-up x-rays. A comparison with 10 patients who had a nonoperated contralateral hip was performed. We found a significant decrease in cortical thicknesses in total hip arthroplasty. The cortical thinning was significant at all periprosthetic levels but less expressed distally. Prosthetic femora were associated with greater cortical thinning as compared with the contralateral nonoperated femora, exceeding that caused by natural aging.

Femoral neck fractures in Lithuania and Sweden. The differences in care and outcome.

PURPOSE: Hip fractures constitute a serious and common health problem from both individual and public health perspectives. Unified data collection and comparison between countries is recognised as an effective tool for care improvements. However, the variation in patients' demography, treatment methods and other local cultural aspects in different countries should be considered. The aim of our study was to compare femoral neck fracture patients treated in Kaunas and Lund, concerning functional outcome and quality of life. METHODS: We investigated 99 patients treated by arthroplasty in Kaunas Clinics and 117 patients in Lund University Hospital. Patients were investigated according to the National Swedish Hip Fracture Register model and were followed up for a period of four months after the injury. The patient's place of residence, mobility, complaints of pain and additional hospital stay were recorded. The EQ-5D questionnaire was used to evaluate quality of life. RESULTS: Patients in Kaunas were significantly younger, had lower ASA grade and were more mobile before trauma and at four moths follow-up. However, when comparing quality of life at four months follow-up between the institutions, Lund patients reported significantly better self care, felt less pain and discomfort, and had less symptoms of anxiety and depression. CONCLUSIONS: The difference observed in quality of life rating between institutions might be related to local cultures of the countries and should be considered when comparing the data.

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.

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.

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.