There is a paucity of data available for the use of Total Femoral Arthroplasty (TFA) for joint reconstruction in the non-oncological setting. The aim of this study was to evaluate TFA outcomes with minimum 5-year follow-up.

This was a retrospective database study of TFAs performed at a UK tertiary referral revision arthroplasty unit. Inclusion criteria were patients undergoing TFA for non-oncological indications. We report demographics, indications for TFA, implant survivorship, clinical outcomes, and indications for re-operation.

A total of 39 TFAs were performed in 38 patients between 2015–2018 (median age 68 years, IQR 17, range 46–86), with 5.3 years’ (IQR 1.2, 4.1–18.8) follow-up; 3 patients had died. The most common indication (30/39, 77%) for TFA was periprosthetic joint infection (PJI) or fracture-related infection (FRI); and 23/39 (59%) had a prior periprosthetic fracture (PPF). TFA was performed with dual-mobility or constrained cups in 31/39 (79%) patients. Within the cohort, 12 TFAs (31%) required subsequent revision surgery: infection (7 TFAs, 18%) and instability (5 TFAs, 13%) were the most common indications. 90% of patients were ambulatory post-TFA; 2 patients required disarticulation due to recurrent PJI. While 31/39 (79%) were infection free at last follow-up, the remainder required long-term suppressive antibiotics.

This is the largest series of TFA for non-oncological indications. Though TFA has inherent risks of instability and infection, most patients are ambulant after surgery. Patients should be counselled on the risk of life-long antibiotics, or disarticulation when TFA fails.

The management of proximal femoral bone loss is a significant challenge in revision hip arthroplasty. A possible solution is the use of a modular proximal femur endoprosthesis (EPR). Although the survivorship and functional outcome of megaprostheses used in tumour surgery has been well described, outcome of EPRs used in revision hip surgery has received less attention. The aim of this study was to determine the 5-year outcome following proximal femur EPR and determine factors that influence it.

This was a retrospective consecutive case series of all EPRs (n=80) performed for non-neoplastic indications, by 6 surgeons, in our tertiary referral centre, between 2005–2014. Patient demographics and relevant clinical details were determined from notes. The most common indications for the use of EPRs included infection (n=40), peri-prosthetic fracture (n=12) and failed osteosynthesis of proximal femoral fractures/complex trauma (n=11). Outcome measures included complication and re-operation rates, implant survival and assessment of functional outcome using the Oxford-Hip-Score (OHS).

The mean age at surgery was 69 years and mean follow-up was 4 (0 – 11) years. The mean number of previous hip operations was 2.4 (range: 0 – 17). Twenty-five patients sustained a complication (31%), the most common being infection (n=9) and dislocation (n=4). By follow-up, further surgery was required in 18 (22%) hips, 9 of which were EPR revisions. 5-yr implant survivorship was 87% (95%CI: 76 – 98%). Mean OHS was 28 (range: 4 – 48). Inferior survival and outcome were seen in EPRs performed for the treatment of infection. Infection eradication was achieved in 34/41 with the index EPR procedure and in 40/41 hips by follow-up.

Limb salvage was achieved in all cases and acceptable complication- and re-operation rates were seen. EPRs for periprosthetic fractures and failed osteosynthesis had best outcome. We recommend the continued use of proximal femur EPR in complex revision surgery.

Hip arthroscopy is particularly attractive in children as it confers advantages over arthrotomy or open surgery, such as shorter recovery time and earlier return to activity. Developments in surgical technique and arthroscopic instrumentation have enabled extension of arthroscopy of the hip to this age group. Potential challenges in paediatric and adolescent hip arthroscopy include variability in size, normal developmental change from childhood to adolescence, and conditions specific to children and adolescents and their various consequences. Treatable disorders include the sequelae of traumatic and sports-related hip joint injuries, Legg–Calve–Perthes’ disease and slipped capital femoral epiphysis, and the arthritic and septic hip. Intra-articular abnormalities are rarely isolated and are often associated with underlying morphological changes.

This review presents the current concepts of hip arthroscopy in the paediatric and adolescent patient, covering clinical assessment and investigation, indications and results of the experience to date, as well as technical challenges and future directions.

Objective

Hip arthroscopy in the setting of hip dysplasia is controversial in the orthopaedic community, as the outcome literature has been variable and inconclusive. We hypothesise that outcomes of hip arthroscopy may be diminished in the setting of hip dysplasia, but outcomes may be acceptable in milder or borderline cases of hip dysplasia.

The management of femoral bone loss is challenging during revision hip arthroplasty. In patients with Paprosky grade IIIB and IV defects, obtaining fixation and rotational stability using traditional surgical constructs is difficult. The use of a custom-made internal proximal femoral replacement prostheses has been proposed as a solution in patients, with severe femoral bone stock loss. However, there is a paucity in the literature on their use and long-term outcomes. We report on the clinical and radiological results of our cohort. We retrospectively reviewed all patients who underwent internal proximal femoral replacement for revision hip arthroplasty between April 1996 and April 2019. All patients had at least 2 years of follow-up time. 160 patients underwent limb salvage at our institution using internal proximal femoral replacement. The mean follow-up was 79.7 months (S.D 41.3). Indications for revision included periprosthetic fractures, aseptic loosening, and deep infection. The mean Oxford hip score increased from 13.8 (0–22) to 31.5 (18–43) (paired t-test, p < 0.001). Kaplan-Meier prosthesis survival analysis with revision as the endpoint was 87% at 5 years. None required revision of the femoral stem. There were four dislocations (5%) and there was failure to eradicate the deep infection in four. This technique allows instant distal fixation, allowing for early mobilisation. Long-term clinical and radiological outcomes are encouraging and the complication rates are acceptable for this patient group

The Canadian Cardiovascular Society (CCS) recommends performing daily troponin testing on postoperative days 0 through 3 for noncardiac surgical patients to decrease the mortality rate due to myocardial injury. Indications for testing include:. ->65 yo. -45-64 yo with significant cardiovascular disease. -a Revised Cardiac Risk Index score (RCRI) > 1. Troponin elevation > 30 ng/L is termed “myocardial injury after noncardiac surgery” (MINS). The study objective was to determine the prognostic relevance of applying CCS recommendations. 669 patients undergoing THA were included in the study. Based on the CCS recommendation there were 4 patient Groups depending on whether or not they met the MINS screening protocol criteria and whether or not it was applied:. -A - met & applied (n=181). -B - met & not applied (n=248). -C – not met & applied (n=10). -D – not met & not applied (n=230). 307 (45.8%) males and 363 (54.2%) females with an average age of 67.8 years were included. Group A- 24% incidence (43 patients) of troponin rise & 5% incidence (9 patients) of cardiac complications. Group B- 0.4% incidence (1 patient) of cardiac complications. Groups A + B – representing all patients who should have had the MINS screening protocol applied according to the CCS recommendations − 10 (2.3%) patients developed cardiac complication and one (0.2%) patient death. MINS screening protocol group (A & C) LOS was 4.0 days compared to 1.4 days for those not screened (p-value: <0.001). Applying the CCS MINS screening protocol to elective THA patients added no benefit in predicting/preventing postoperative cardiac events but was associated with a significant increase in LOS. Following current CCS recommendations without more specifications and clinical evidence is unwarranted

The benefit of dual mobility cup (DMC) for primary total hip arthroplasties (THA) is still controversial. This study aimed to compare 1) the complications rate, 2) the revisions rate, 3) the survival rate after monobloc DMC compared to large femoral heads (LFH) in primary THA. Between 2010 and 2019, 2,075 primary THA using cementless DMC or LFH were included. Indications for DMC were patients older than 70 years old or with high risk of dislocation. Every other patient received a LFH. Exclusion criteria were cemented implants, femoral neck fracture, a follow-up of less than one year. 1,940 THA were analyzed: 1,149 DMC (59.2%), 791 LFH (40.8%). The mean age was 73 ±9.2 years old in DMC group and 57 ±12 in LFH group. The complications and the revisions have been assessed retrospectively. The mean follow-up was 41.9 months ±14 [12–134]. There were significantly fewer dislocations in DMC group (n=2; 0.17%) compared to LFH group (n=8; 1%) (p=0.019). The femoral head size had no impact on the dislocations rate in LFH group (p=0.70). The overall complication rate in DMC (n=59; 5.1%) and LFH (n=53; 6.7%) were not statistically different (p=0.21). No specific complication was attributed to the DMC. In DMC group, 18 THA (1.6%) were revised versus 15 THA in LFH group (1.9%) (p= 0.71). There was no statistical difference for any cause of revisions in both groups. The cup aseptic revision-free survival rates at 5 years were 98% in DMC group and 97.3% in LFH group (p=0.78). Monobloc DMC had a lower risk of dislocation in a high-risk population than LFH in a low-risk population at the mid-term follow-up. There was no significant risk of specific complications or revisions for DMC in a large cohort. Monobloc DMC can be safely used in a selected high-risk population

The purpose of this study was to determine long-term survival free from all-cause revision and stem-related failure, as well as radiographic and functional outcomes of the ZMR stem in revision THA. We retrospectively identified all patients in our institutional database who underwent revision THA using the ZMR Revision Hip system from the year 2000 to 2007 (minimum two-year follow-up). Of the 112 ZMR hips (110 patients) identified, a total of 106 hips (104 patients) met inclusion criteria. The mean study follow-up 13.9 years (range 2–22). Indications for index ZMR revision included aseptic loosening (72.1%), periprosthetic joint infection (17.3%), periprosthetic fracture (9.6%), and stem fracture (1.0%). Kaplan-Meier analysis was used to determine the all-cause and stem-related failure revision-free survival. Validated patient reported outcomes were collected and available radiographs were reviewed to determine implant stability. A total of 17 hips (16.0%) underwent a re-revision of any component. The indications for re-revision were stem failure (35.3%), infection (29.4%), instability (29.4%), and aseptic loosening of the acetabular component (5.9%). The five- and 15-year all-cause survivorship was 89.5% (95% CI 86.5–92.5) and 83.0% (95% CI 79.2–86.8), respectively. There were six re-revisions for stem failure (5.7%); five for stem fracture and one for aseptic loosening. The average time to stem failure was 4.6 years (range 1.3–8.2). The five- and 15-year survivorship free from stem-related failure was 97.2% (95% CI 95.6–98.8) and 93.9% (95% CI 91.5–96.3), respectively. At final follow-up the mean Oxford hip score was 36.9 and all surviving ZMR stems were well fixed on radiographs. Femoral revision with the ZMR stem offers satisfactory long-term survivorship and promising clinical outcomes. Although uncommon, stem fracture was the most common reason for stem-related failure

This large UK multicentre study evaluates clinical outcomes and identifies factors associated with local complication following PFR for non-oncological conditions. 132 patients across four UK centres underwent PFR from 01/08/2004-28/03/2023 with median follow-up of 1.9 (Q10.5-Q34.2) years. 75 (56.8%) patients were female and the mean age was 74.0 (SD 11.7) years. 103 (78%) patients had Charleston Comorbidity Index ≥3. ASA class was III or IV in 66.6%. Indications were infected revision (39, 29.5%), periprosthetic fracture (36, 27.3%), acute trauma (30, 22.7%), aseptic revision (17, 12.9%), failed trauma (nine, 6.8%) and complex primary arthroplasty (one, 0.8%). The primary outcome was the local complication rate. Secondary outcomes were systemic complications, reoperation and mortality rates. Comparisons were made with t-tests and Chi2 tests to investigate patient and surgical factors associated with local complication. Statistical significance was p<0.05. There were 37(28.0%) local complications. These were 18 (13.6%) dislocations, eight (6.1%) prosthetic joint infections, four (3.0%) haematomas, three (2.3%) superficial infections, one (0.8%) wound dehiscence, one (0.8%) sciatic nerve palsy and one (0.8%) femoral perforation. Dislocation mostly occurred in conventional articulations (12, 9.1%) followed by dual-mobility cups (three, 2.3%), constrained cups (two, 1.5%) and hemiarthroplasty (one, 0.8%). Median time to local complication was 30 (Q14-Q3 133) days. Seven (5.3%) patients developed a systemic complication. Thirty-three (25.0%) patients underwent reoperation. Thirty-day and one-year mortality rates were 3.8% and 12.1%, respectively. Longer surgical waiting times (7.9 \[SD 16.9) versus 2.6 \[SD 4.4\] days, p<0.001) and longer operating times (212.5 \[SD 71.8\] versus 189.4 \[SD 59.3\] mins, p=0.0450) were associated with local complication. Due to its high complication rate, PFR should be a salvage option when performed for non-oncological indications. Conventional articulations should be avoided. PFR should be delivered in a timely manner and ideally as dual-consultant cases to reduce operating time

Constrained acetabular inserts provide a solution for both complex primary and revision hip arthroplasty, but there have been ongoing concerns for high risk of failure and their longevity. The Stryker® Trident acetabular insert is pre-assembled with its constrained ring. We believe this to be the largest series of constrained acetabular inserts with a minimum of 5 year follow-up. We retrospectively reviewed all Stryker® Trident ‘All-Poly’ constrained acetabular inserts cemented into bone in our unit between 2008 and 2016. We collated demographic details and reviewed all patients’ radiographs and clinical notes. Indications for surgery, latest Oxford Hip Scores (OHS) and clinical and radiographic complications were identified. 117 consecutive Stryker® Trident ‘All-Poly’ constrained inserts were cemented into bone in 115 patients during the study period with a mean age of 80 (47–97). Most common indications for surgery were recurrent dislocation (47), complex primary arthroplasty (23), revision arthroplasty (19) and failed hemiarthroplasty (12). 41 patients required revision of the acetabular component only. Follow-up was a minimum of 5 years (mean 8.6, range 5–13). There were three 30-day mortalities and six 1-year mortalities. The mean latest OHS was 37 (24–45). Four cups failed in three patients, one at the cement-bone interface, two at the cement-prosthesis interface and one at the bipolar interface. These were treated conservatively in three patient and with excision arthroplasty in one patient. There were four peri-prosthetic fractures, one Vancouver C distal femur fracture treated conservatively and three Vancouver B1 fractures, two treated conservatively and one treated with open reduction internal fixation. There was breakage of one constrained ring with no adverse effects and one superficial wound infection requiring oral antibiotics only. This series demonstrated that despite the elderly and complex nature of these patients’ clinical situations, constrained acetabular inserts offer a useful and pragmatic solution, with relatively low complications, including in our series a cup failure rate of 3% and peri-prosthetic fracture rate of 3%

Background. Ultraporous metals have now been used in acetabular reconstruction for two decades with excellent survival. The purpose of this study is to evaluate a newer porous metal made from Ti6Al4V titanium alloy in complex primary and revision hip arthroplasty. Methods. A retrospective review as performed on all total hip arthroplasty (THA) procedures in which a G7 Osseo-Ti (Zimmer Biomet, Warsaw, IN) acetabular component was used between 2015 and 2017. Patients with 2-year minimum follow-up or failure were included, yielding a cohort of 123 patients (126 hips). There were 50 male patients (41%; 51 hips) and 73 females (59%; 75 hips). Mean age was 65 years (range, 43–88) and mean BMI was 30.7 kg/m. 2. (range, 18–56). Indications for ultraporous metal components were in hips with compromised bone stock or severe acetabular deformity. Procedures were 35 complex primary THA and 91 revision THA that included 12 conversions and 24 reimplantations as part of 2-staged exchange for treatment of infection. Results. With an average 3.3-year follow-up (range, 2–5 years), 1 hip in the primary series (2.9%) and 4 hips in the revision series (4.4%) were revised for aseptic loosening of the acetabular component. Three of these re-revisions required custom triflange devices. Five patients (4%) failed for periprosthetic infection, which included 1 primary THA done for rheumatoid arthritis and post-radiation necrosis, and 4 second-stage reimplantation revision THAs for prior infection. Two revision patients, one done for active instability and one multiply revised, subsequently dislocated and required liner revision to constrained constructs. Kaplan-Meier analysis to endpoint of acetabular revision for aseptic loosening was 96.6% (±3.4%) in the primary series and 95.3% (±2.3%) in the revision series. Conclusion. This three-dimensionally printed ultraporous titanium acetabular component demonstrated promising early results in complex primary and revision total hip arthroplasty

Aims. Modular dual-mobility constructs reduce the risk of dislocation after revision total hip arthroplasty (THA). However, questions about metal ions from the cobalt-chromium (CoCr) liner persist, and are particularly germane to patients being revised for adverse local tissue reactions (ALTR) to metal. We determined the early- to mid-term serum Co and Cr levels after modular dual-mobility components were used in revision and complex primary THAs, and specifically included patients revised for ALTR. Patients and Methods. Serum Co and Cr levels were measured prospectively in 24 patients with a modular dual-mobility construct and a ceramic femoral head. Patients with CoCr heads or contralateral THAs with CoCr heads were excluded. The mean age was 63 years (35 to 83), with 13 patients (54%) being female. The mean follow-up was four years (2 to 7). Indications for modular dual-mobility were prosthetic joint infection treated with two-stage exchange and subsequent reimplantation (n = 8), ALTR revision (n = 7), complex primary THA (n = 7), recurrent instability (n = 1), and periprosthetic femoral fracture (n = 1). The mean preoperative Co and Cr in patients revised for an ALTR were 29.7 μg/l (2 to 146) and 21.5 μg/l (1 to 113), respectively. Results. Mean Co and Cr levels were 0.30 μg/l and 0.76 μg/l, respectively, at the most recent follow-up. No patient had a Co level ≥ 1 μg/l. Only one patient had a Cr level ≥ 1 μg/l. That patient’s Cr level was 12 μg/l at 57 months after revision THA for ALTR (and decreased ten-fold from a preoperative Cr of 113 μg/l). Conclusion. At a mean of four years, no patient with a modular dual-mobility construct and ceramic femoral head had elevated Co levels, including seven patients revised specifically for ALTR. While further studies are required, we support the selective use of a modular dual-mobility construct in revision and complex primary THAs for patients at high risk for instability. Cite this article: Bone Joint J 2019;101-B(6 Supple B):57–61

Background. Hip resurfacing arthoplasty (HRA) showed promising early and mid-terms results at the beginning of the new millennium. Adverse local tissue reactions associated with metal debris considerably slowed down the implantation of HRA which use is now limited to a few specialized centers. The long term success of this procedure, however, is still largely unknown. This study aimed to provide the clinical results of a series of 400 consecutive HRA with a minimum follow-up of 20 years. Methods. All patients treated with Conserve. ®. Plus HRA between November 1996 and November 2000 were retrospectively selected and 355 patients (400 hips) were included. The clinical results of this series was previously reported in 2004 at a follow up of 2 to 6 years[1]. There were 96 women (27%) and 259 men (73%). Mean age at surgery was 48.2 ± 10.9 years. Long-term survivorship was assessed with Kaplan-Meier survival estimates. UCLA hip scores and SF-12 quality of life scores were collected at follow-up visits. Radiographic positioning of the acetabular component was assessed with the computation of the contact patch to rim (CPR) distance. Radiolucencies about the metaphyseal stem and around the acetabular component were recorded to assess the quality of the component fixation. Results. The mean time of follow up was 16.3 ± 5.5 years including 183 hips beyond 20 yrs. Nine hips were lost to follow up (2.2%) Thirty-three patients (35 hips,8.8%) died of causes unrelated to the surgery at a mean 11.9 ± 5.3 years after surgery The mean UCLA hip scores at last follow-up were 9.3 ± 1.0, 9.1 ± 1.4, 9.0 ± 1.8, and 6.9 ± 1.7 for pain, walking, function, and activity, respectively. Post-operative SF-12 scores were 48.4 ± 10.3 for the physical component and 48.5 ± 15.5 for the mental component and did not differ from those of the general US population. Fifty-five patients (60 hips) underwent revision surgery at a mean time of 9.3 ± 5.8 years. Indications for revision surgery included acetabular component loosening (12 hips), femoral component loosening (31 hips), femoral neck fracture (6 hips), wear (6 hips), sepsis (2 hips), recurrent dislocations (1 hip), acetabular component protrusion after over-reaming (1 hip) and unknown (1 hip which was revised in another center). Using any revision as an endpoint, the Kaplan-Meier survivorship was 95.2% at 5 years, 91.2% at 10 years, 87.3% at 15 years, and 83.2% at 20 years. A multivariate model for risk factor analysis showed a diagnosis of developmental dysplasia (p=0.020) and a low body mass index (typically associated with higher levels of activity) (p=0.032), to be significantly related to revision for any reason. Female sex was not a risk factor after adjustment for hip dysplasia and component size was made (Table 1). There was only 1 femoral failure (a late neck fracture 19 years after surgery) among the hips reconstructed with a cemented metaphyseal stem (n=59). Five of the 6 hips (1.5%) with wear-related failures all had mal-positioned sockets (CPR distance <10mm) and were therefore preventable. There were no cases with a high score of aseptic lymphocytic vasculitis-associated lesions (ALVAL)[2], suggesting metal sensitivity. X-ray analysis showed excellent persisting fixation in all but one hip. Conclusions. In this group of patients operated over 20 years ago, HRA keeps providing excellent pain relief and quality of life to the patients. Subsequent progress in the preparation of the femoral head has considerably reduced the failure rate on the femoral side which was the main mode of failure in this initial series[3, 4]. The 83.1% 20 year survivorship of this initial series surpasses that of total hip arthroplasties in use 20 years ago in this young patient population[5]. Life-long durability of the device is anticipated for most of the remaining patients. The established benefits of this procedure, such as a low dislocation rate, an anatomic reconstruction with physiologic loading of the proximal femur, the absence of taper corrosion, and an easy conversion if ever necessary, make HRA a preferable alternative to THA in young and active patients. For any figures, tables, or references, please contact the authors directly

Aims

The aim of this study was to compare open reduction and internal fixation (ORIF) with revision surgery for the surgical management of Unified Classification System (UCS) type B periprosthetic femoral fractures around cemented polished taper-slip femoral components following primary total hip arthroplasty (THA).

Aims

The aim of this study is to report the long-term outcomes of instrumented femoral revisions with impaction allograft bone grafting (IBG) using the X-change femoral revision system at 30 years after introduction of the technique.

Background. Antibiotic loaded bone cement (ALBC) is commonly used in cemented total hip arthroplasty (THA) in an attempt to reduce the risk of prosthetic joint infection (PJI). However, its role versus plain cement remains controversial due to the potential risk of developing resistant organisms and potential excess costs incurred from its usage. We investigated the relationship of ALBC and plain cement in affecting outcome of revision surgery after primary THA. Methodology. We conducted a retrospective study of data collected from National Joint Registry for England and Wales, Northern Ireland and the Isle of Man between 1. st. September 2005 until 31. st. August 2017. A logistic regression analysis model was used to investigate the association between ALBC versus plain cement and the odds ratio (OR) for revision, adjusting for age, ASA grade, bearing surfaces, head size and cup and stem fixation. Indications for revision recorded in NJR were considered in separate models. Results. We identified 418,925 THAs where bone cements were used (22,037 plain cement; 396,888 ALBC). After adjusting for confounding factors, the risk of revision for infection was lower with ALBC (OR 0.77, 95% CI 0.62–0.95). There was also lower risk of revision for aseptic loosening of stem (OR 0.53, 95% CI 0.39–0.72), aseptic loosening of socket (OR 0.46, 95% CI 0.37– 0.58). When breaking down hips into fully cemented or hybrid fixation, the protective effect of ALBC against infection was only apparent in fully cemented (OR 0.65, 95% CI 0.48–0.87) when compared against hybrid fixation (OR 0.90, 95% CI 0.66–1.23). Discussion. Within the limits of registry analysis, this study has demonstrated an association between the use of ALBC and lower rates of revision for infection and aseptic loosening. Conclusion. This finding supports the current use of ABLC in cemented THAs

Aims

Dislocation remains a leading cause of failure following revision total hip arthroplasty (THA). While dual-mobility (DM) bearings have been shown to mitigate this risk, options are limited when retaining or implanting an uncemented shell without modular DM options. In these circumstances, a monoblock DM cup, designed for cementing, can be cemented into an uncemented acetabular shell. The goal of this study was to describe the implant survival, complications, and radiological outcomes of this construct.

Aims

This study compares the re-revision rate and mortality following septic and aseptic revision hip arthroplasty (rTHA) in registry data, and compares the outcomes to previously reported data.

Aims

Contemporary outcomes of primary total hip arthroplasties (THAs) with highly cross-linked polyethylene (HXLPE) liners in patients with inflammatory arthritis have not been well studied. This study examined the implant survivorship, complications, radiological results, and clinical outcomes of THA in patients with inflammatory arthritis.

Aims

The aim of this study was to examine the implant accuracy of custom-made partial pelvis replacements (PPRs) in revision total hip arthroplasty (rTHA). Custom-made implants offer an option to achieve a reconstruction in cases with severe acetabular bone loss. By analyzing implant deviation in CT and radiograph imaging and correlating early clinical complications, we aimed to optimize the usage of custom-made implants.