Cement Mantle Quality and Stem Alignment in Cemented Collarless Polished Tapered Stems Implanted via the Direct Anterior and Direct Lateral Approaches: A Single Institution Experience.

BACKGROUND: The aim of this study was to compare the stem alignment and the quality of cement mantle of collarless polished tapered cemented stems inserted through the direct anterior approach (DAA) and the direct lateral approach (DLA). METHODS: A comparative retrospective study of 232 hybrid total hip arthroplasties using a cemented collarless polished tapered stem through either the DAA (n = 147) or DLA (n = 85) was performed. Radiographic evaluation included stem alignment, cement mantle quality, and cement mantle thickness. RESULTS: On anteroposterior radiographs, stems implanted through the DLA were more likely to be in neutral alignment, than those implanted through the DAA (83.5%[n = 71] versus 71.4% [n = 105]; P = <.001). No difference between approaches was noted for stem alignment on lateral radiographs or cement mantle quality. Multivariate analysis revealed factors associated with suboptimal cement mantle and included Dorr type B or C femur as well as male gender. A mean cement mantle thickness ≥2mm was achieved in all Gruen zones for both approaches. CONCLUSION: In our series, the DAA was associated with a higher incidence of coronal plane stem malalignment compared to the DLA when using cemented tapered polished femoral components for total hip arthroplasty. No difference in lateral stem alignment or cement mantle quality was found.

Can We Predict Fracture When Using a Short Cementless Femoral Stem in the Anterior Approach?

BACKGROUND: Short cementless femoral stems may allow for easier insertion with less dissection. The use of short stems with the anterior approach (AA) may be associated with a considerable perioperative fracture risk. Our aim was to evaluate whether patient-specific femoral and pelvic morphology and surgical technique, influence the perioperative fracture risk. Furthermore, we sought to describe important anatomical thresholds alerting surgeons. METHODS: A single-center, multi-surgeon retrospective, case-control matched study was performed. Thirty nine periprosthetic fractures (3.4%) in 1,145 primary AA THAs using short cementless stems were identified. These were matched with 78 THA nonfracture controls for factors known to increase the fracture risk. A radiographic analysis using validated software measured femoral (canal flare index [CFI], morphological cortical index [MCI], and calcar-calcar ratio [CCR]) and pelvic (Ilium-ischial ratio [IIR], ilium overhang, and anterior superior iliac spine [ASIS] to greater trochanter distance) morphologies and surgical techniques (% canal fill). A multivariate and Receiver-Operator Curve (ROC) analysis was used to identify fracture predictors. RESULTS: CFI (3.7 ± 0.6 vs 2.9 ± 0.4, P < .001) and CCR (0.5 ± 0.1 vs 0.4 ± 0.1, P = .006) differed. The mean IIR was higher in fracture cases (3.3 ± 0.6 vs 3.0 ± 0.5, P < .001). Percent canal fill was reduced in fracture cases (82.8 ± 7.6 vs 86.7 ± 6.8, P = .007). Multivariate and ROC analyses revealed a threshold CFI of 3.17 which was predictive of fracture (sensitivity: 84.6%/specificity: 75.6%). The fracture risk was 29 times higher when patients had CFI >3.17 and II ratio >3 (OR: 29.2 95% CI: 9.5-89.9, P < .001). CONCLUSION: Patient-specific anatomical parameters are important predictors of a fracture-risk. A careful radiographic analysis would help identify those at a risk of early fracture using short stems, and alternative stem options should be considered.

Supine versus lateral position for total hip replacement: accuracy of biomechanical reconstruction.

BACKGROUND: Restoration of normal hip anatomy and biomechanics is a key surgical goal for success in total hip arthroplasty. The aim of this study was to evaluate the influence, if any, that patient positioning in the supine and lateral decubitus positions has in achieving this goal. MATERIALS AND METHODS: A single center multi-surgeon case-matched series from a tertiary level referral center of patients undergoing primary unilateral THA for osteoarthritis between April 2018 and December 2019 was retrospectively analyzed. Patients (n = 200) were divided into two matched groups: supine (anterior approach, n = 100) and lateral decubitus (direct lateral or posterior/SuperPATH™ approaches, n = 100). Post-operative anteroposterior pelvic radiographs were analyzed using a previously validated software (SurgiMap, Nemaris Inc., USA) for parameters of reconstruction of the hip in the coronal plane; leg length discrepancy, vertical and horizontal displacement of the center of rotation, femoral offset, and total offset. RESULTS: Mean absolute leg length discrepancy in the supine group was 0.6 ± 3.3 mm (95% [CI] - 0.1 to 1.2 mm) versus 2.4 ± 3.8 mm (95% [CI] 1.6 to 3.1) in the lateral decubitus position (p < 0.001). The center of rotation was displaced medially by a mean of 3.2 ± 2.7 mm in the supine group versus 1.3 ± 4.0 mm in the lateral decubitus group (p < 0.001). For a surgical target of reconstructing both leg length and total offset within 5 mm of native anatomy, the supine group was more than twice as likely to achieve these goals with fewer outliers (OR 2.631, 95% [CI] 1.901-3.643) (76% v 30%, p < 0.001). CONCLUSION: Total hip arthroplasty through the anterior approach in the supine position is more consistent and accurate for the restoration of leg length and total offset. Further study is required to assess how this translates with outcome. LEVEL OF EVIDENCE: III-retrospective cohort study.

High reported rate of return to play following bone marrow stimulation for osteochondral lesions of the talus.

PURPOSE: The purpose of this study is to systematically review the literature and to evaluate the reported rehabilitation protocols, return to play guidelines and subsequent rates and timing of return to play following bone marrow stimulation (BMS) for osteochondral lesions of the talus (OLT). METHODS: MEDLINE, EMBASE and the Cochrane Library were searched according to the PRISMA guidelines in September 2017. The rate and timing of return to play was assessed. The rehabilitation protocols were recorded, including time to start range of motion, partial weight-bearing and complete weight-bearing. RESULTS: Fifty-seven studies with 3072 ankles were included, with a mean age of 36.9 years (range 23-56.8 years), and a mean follow-up of 46.0 months (range 1.5-141 months). The mean rate of return to play was 86.8% (range 60-100%), and the mean time to return to play was 4.5 months (range 3.5-5.9 months). There was large variability in the reported rehabilitation protocols. Range of motion exercises were most often allowed to begin in the first week (46.2%), and second week postoperatively (23.1%). The most commonly reported time to start partial weight-bearing was the first week (38.8%), and the most frequently reported time of commencing full weight-bearing was 6 weeks (28.8%). Surgeons most often allowed return to play at 4 months (37.5%). CONCLUSIONS: There is a high rate of return following BMS for OLT with 86.8% and the mean time to return to play was 4.5 months. There is also a significant deficiency in reported rehabilitation protocols, and poor quality reporting in return to play criteria. Early weightbearing and early postoperative range of motion exercises appear to be advantageous in accelerated return to sports. LEVEL OF EVIDENCE: Level IV.

Primary appendicular soft-tissue sarcoma resection: What tumour parameters affect wound closure planning?

Wound closure after wide, local excision of an appendicular soft-tissue sarcoma (STS) can be challenging. This study evaluates the value of magnetic resonance imaging (MRI)-based tumour parameters in planning wound closure. A total of 71 patients with a primary limb-based STS, excluding vascular or osseous involvement, excluding the shoulder or hand and hip or foot were included. Axial MRI images were used to measure the circumferences and cross-sectional areas of the limb, bone, and tumour. The tumour diameter, length, and depth at the level of maximal tumour dimension were measured to identify the tumour's relative contribution to the planning of optimal wound closure management through primary closure (PC) or reconstructive surgery (RS). Eighteen patients required planned wound RS. Wound complications occurred in 14% overall. Tumours, which were closed by PC, were of significantly greater depth, shorter radial diameter, and shorter tumour circumference relative to those closed by RS. On multivariate analysis, tumour depth was the greatest contributory factor in predicting type of wound closure. A quantitative analysis of MRI-based tumour parameters demonstrates tumour depth as the most predictive factor in planning for the type of wound closure and may prove beneficial in providing greater insight into planned wound management of sarcoma resection.

A prospective evaluation of bone marrow aspirate concentrate and microfracture in the treatment of osteochondral lesions of the talus.

BACKGROUND: The term osteochondral lesion (OCL) refers to a defect involving the chondral surface and or subchondral bone. These lesions are associated with ankle injuries with bony and soft tissue and cause pain, decreased range of motion, swelling and impact adversely on quality of life. To date the standard treatment has been isolated microfracture (BMS). The aim of this study was to compare the outcomes of BMS alone to BMS augmented with bone marrow aspirate concentrate (BMAC) in the treatment of ankle OCLs. METHODS: This study was a prospective cohort study carried out from 2010-2015 in a single surgeon's practice. Patients from 2010-2012 were treated with microfracture alone while patients from 2013-2015 were treated with micro fracture augmented with bone marrow aspirate concentrate and fibrin glue. Self-reported patient outcome measures were measured. Complications, revision rates, and visual analogue pain scores were compared. RESULTS: 101 patients were included in the study. 52 patients were in the microfracture group while 49 patients were in the microfracture/BMAC group. The minimum follow-up for both groups was 36 months. Both groups had a statistically significant improvement in pain scores, quality of life scores, participation in sport and activities of daily living. The revision rate was 28.8% in the microfracture group versus 12.2% in the microfracture/BMAC group, which was statistically significant, p=0.0145. The majority of the lesions were less than 1.5cm2 in diameter in both cohorts. CONCLUSIONS: Microfracture and bone marrow aspirate concentrate appears to be a safe and effective treatment option for osteochondral lesions of the talus. The addition of bone marrow aspirate concentrate does not result in any increase in ankle or donor site morbidity. It is a well-tolerated therapy which decreases revision rates for treatment of the osteochondral lesions when compared to microfracture alone. LEVEL OF EVIDENCE: Level III.

Peroneus Tertius Tendon Tear Causing Lateral Ankle Pain in a Child.

The peroneus tertius muscle arises in the anterior compartment of the leg and demonstrates significant morphologic variation. Its function is not yet clearly delineated. We present the case of a 12-year-old patient with an isolated tear of the peroneus tertius tendon that resulted in lateral based ankle pain. After surgical reconstruction, the patient's pain resolved, and he was able to return to his normal activities.

Prospective Evaluation of Intra-Articular Sodium Hyaluronate Injection in the Ankle.

Viscosupplementation by injection of hyaluronic acid into the ankle can be used to provide pain relief and to delay the need for surgery in patients with osteoarthritis of the ankle. In the present investigation, we prospectively evaluated 50 consecutive patients (25 males and 25 females) undergoing a 3-injection protocol of sodium hyaluronate viscosupplementation in the ankle from January 2014 to January 2015. The Foot and Ankle Outcomes Score was used to compare the patients' pre- and post-treatment opinions about their ankle problems. The mean pretreatment Foot and Ankle Outcomes Score was 48 ± 6.3 (range 25 to 84) and the 6-month post-treatment score was 78 ± 5.8 (range 48 to 100). This difference was statistically significant (p = .003). From our findings in the present prospective cohort study, we have concluded that intra-articular injection of sodium hyaluronate viscosupplementation is a useful conservative therapy for osteoarthritis of the ankle.

Single Oblique Incision for Simultaneous Open Reduction and Internal Fixation of the Posterior Malleolus and Anterior Syndesmosis.

Several surgical approaches to the posterior malleolus have been described. However, these approaches may make it difficult for fixation of associated lateral malleolar and anterior syndesmotic fractures. A single incision approach is described that allows safe access to the posterior malleolus while also facilitating access to the lateral malleolus and anterior syndesmosis.

A prospective review of Cauda Equina Syndrome referrals received by an on-call orthopaedic department at a major trauma unit.

INTRODUCTION: Cauda Equina Syndrome (CES) is one of the genuine orthopaedic emergencies. Diagnosis of acute CES is challenging and may be missed, resulting in considerable medicolegal claims. In Ireland, nearly €21 million in compensation has been paid out over a 10-year period due to the diagnosis being missed. As a result, defensive practices have resulted in an increased number of referrals for CES to the on-call orthopaedic service in a major trauma unit. METHODS: A prospective data-capturing exercise was carried out of all referrals for acute CES to the orthopaedic on-call department in a tertiary-level university-affiliated teaching hospital between August and November 2023. Qualitative data was captured including referral source, referring clinician grade, in-hours or out-of-hours referral, MRI on referral, red flags as identified by the referring team, red flags as identified by the orthopaedic team, and outcome. RESULTS: Forty referrals for CES were made over the duration of this audit. Seventeen (42.5%) referrals were made in-hours, and 23 (57.5%) were referred out-of-hours. Only five (12.5%) of these referrals had an MRI done at the time of the referral. No patients were transferred for an out-of-hours MRI to another hospital. Only five (12.5%) patients required surgical decompression-none of these patients required an out-of-hours emergent decompression. CONCLUSION: There is a lack of understanding as to what exactly is being referred-resulting in a referral volume which is over ten times the expected number of CES cases being made to our unit. The lack of out-of-hours MRI access poses a significant concern for patient outcomes.

Contemporary, non-navigation, cup orientation techniques improve accuracy and eliminate differences seen between the anterior and posterior approach in THA.

BACKGROUND: This study aimed to: (1) Determine the ability to achieve the surgeons' desired cup orientation, without navigation, using contemporary measures with the anterior- (AA) and posterior- approaches (PA); and (2) assess whether surgical approach is associated with cup orientation accuracy, as previously reported, when contemporary measures are used. METHODS: A prospective, 2-centre, multi-surgeon study of 400 THAs (200 AA; 200 PA) was performed. Intraoperative radiographs were obtained with the AA. A digital inclinometer and 3-point pelvic support were used with the PA. With the PA, intraoperative cup inclination at impaction was recorded. Radiographic inclination/anteversion (RI/RA) was measured from intraoperative radiographs (AA-only) and from postoperative radiographs for all cases. Optimum inclination/anteversion was defined as 40°/20° (±10°). The difference between intra- and postoperative orientations allowed for determination of the difference in pelvic position at impaction. RESULTS: Optimum RI and RA were achieved in 91.3% (n = 365) and 92% (n = 368) of cases respectively. Optimum cup orientation was detected in 84% of cases (n = 336). There was equivalent ability to achieve cup orientation between approaches (AA: 82.5% vs. PA: 85.5%; p = 0.41). The use of an inclinometer in the PA was associated with a smaller variability of inclination at implantation (10° vs. 14°) and counteracted the greater difference in pelvic position (4.4° vs. 2.1°) seen with the PA. CONCLUSIONS: Over 80% of cases can have optimum orientation without navigation, using simple, cheap contemporary measures. Such measures eliminate differences between approaches, related to patient position. Narrower implantation angles will further reduce variability in cup orientation achieved.

Gluteal compartment syndrome following bone marrow biopsy: a case report.

Compartment syndrome is a well described limb-threatening and potentially life-threatening condition. Compartment syndromes of the upper and lower limbs are well documented in the literature. The gluteal region, however, is often not considered as a compartment despite having three osseofascial boundaries. We report a case of gluteal compartment syndrome which resulted from a bone marrow biopsy. The patient was anticoagulated at the time. The outcome was residual right sided foot drop due to sciatic nerve palsy. This case describes an unusual presentation of a rare condition. Gluteal compartment syndrome is a potential complication of bone marrow biopsy.

Acute traumatic spinal injury following bicycle accidents: a report of three cases.

Although the vast majority of injuries suffered while cycling are minor, acute spinal injuries have been reported. We describe three cases of acute spinal injury occurring while cycling. All three patients reported being thrown over the handlebars, while travelling downhill at speed. Two of the cases resulted in profound neurological deficit. These cases show that there is a spectrum of spinal injury due to bicycle accidents, ranging from no neurological deficit to profound insult, and from high cervical injury to mid-thoracic spinal injury. In cases of bicycle accidents, increased awareness of the possibility of such spinal injury is advisable.

The accuracy in determining pelvic tilt from anteroposterior pelvic radiographs in patients awaiting hip arthroplasty.

Spinopelvic mobility affects outcome after THA. Whether the sacro-femoral-pubic (SFP) angle, measured on AP radiographs, can be reliably used to estimate pelvic tilt (PT) in hip osteoarthritis patients is unknown. This study aimed to (1) validate the use of the SFP angle in the calculation of PT from AP radiographs, and (2) identify individual patient factors affecting the estimation of PT. A cohort of 100 patients awaiting THA for end-stage hip osteoarthritis was prospectively studied. AP and lateral radiographs, taken in the standing and relaxed-seated positions were evaluated for spinopelvic measurements (SFP, PT, and pelvic incidence [PI]). To validate the SFP angle, estimated PT values using the formula [PT = 75°-SFP] were compared to the true, measured values from the lateral radiographs. Despite good agreement for the estimated and true PT (16.2 ± 5.9° vs. 15.5 ± 8.6°; p = .315), a significantly poorer agreement could be found between the two methods at high or low values of PT. Patient-specific PI correlated with the difference between the two measurement methods (Pearson's r = -0.644; p < .001). However, the change in SFP angle equaled approximately the change in pelvic tilt (∆PT = 2°-∆SFP; Pearson's r = -0.934; p < .001). Absolute values for the sagittal PT should not be estimated from AP pelvic radiographs in patients awaiting total hip arthroplasty. However, the relative change in PT between different positions equals approximately the change in SFP angle. This may allow functional cup orientation after THA to be determined between different postures from an AP radiograph of the pelvis. The SFP angle has moderate accuracy in determining a patient's pelvic tilt; however, it can accurately determine a patient's change in pelvic tilt in different positions.

Mode I and II Wear in Ceramic on Ceramic Total Hip Arthroplasty: A Case Report.

INTRODUCTION: Elective total hip arthroplasty (THA) is a common procedure and has been associated with favorable outcomes in both elderly and younger patients. A variety of implant and articular components exist so to allow surgeons to make a patient-specific choice with the intent of maximizing both patient outcomes and implant survival.The utilization of ceramic bearing surfaces during THA has become increasingly prevalent, with their tribological profile conveying favorable wear and osteolysis-resistant properties. Typically, ceramic articulating components are most susceptible to failure through brittle fracture or complications such as squeaking. CASE REPORT: This case describes a 68-year-old Caucasian male who underwent revision of ceramic on ceramic THA due to pain, with intraoperative analysis revealing evidence of gross Mode I acetabular ceramic component wear with a resultant Mode II wear articulation between the ceramic femoral head and acetabular liner. CONCLUSION: Wear between ceramic implants in THA is infrequently reported, and as such awareness of this uncommon phenomena as well as its potential causative factors is important when considering either primary or revision THA involving ceramic bearing components.

Cementing a collarless polished tapered femoral stem through the anterior approach : evaluation of cement mantle quality and component alignment.

AIMS: The aim of this study was to radiologically evaluate the quality of cement mantle and alignment achieved with a polished tapered cemented femoral stem inserted through the anterior approach and compared with the posterior approach. METHODS: A comparative retrospective study of 115 consecutive hybrid total hip arthroplasties or cemented hemiarthroplasties in 110 patients, performed through anterior (n = 58) or posterior approach (n = 57) using a collarless polished taper-slip femoral stem, was conducted. Cement mantle quality and thickness were assessed in both planes. Radiological outcomes were compared between groups. RESULTS: No significant differences were identified between groups in Barrack grade on the anteroposterior (AP) (p = 0.640) or lateral views (p = 0.306), or for alignment on the AP (p = 0.603) or lateral views (p = 0.254). An adequate cement mantle (Barrack A or B) was achieved in 77.6% (anterior group, n = 45) and in 86% (posterior group, n = 49), respectively. Multivariate analysis revealed factors associated with unsatisfactory cement mantle (Barrack C or D) included higher BMI, left side, and Dorr Type C morphology. A mean cement mantle thickness of ≥ 2 mm was achieved in all Gruen zones for both approaches. The mean cement mantle was thicker in zone 7 (p < 0.001) and thinner in zone 9 for the anterior approach (p = 0.032). Incidence of cement mantle defects between groups was similar (6.9% (n = 4) vs 8.8% (n = 5), respectively; p = 0.489). CONCLUSION: An adequate cement mantle and good alignment can be achieved using a collarless polished tapered femoral component inserted through the anterior approach. Cite this article: Bone Joint J 2021;103-B(7 Supple B):46-52.

Bone Marrow Aspirate Concentrate and Microfracture Technique for Talar Osteochondral Lesions of the Ankle.

Osteochondral lesions of the talus refer to a chondral or subchondral defect of the articular cartilage and potentially the underlying bone. Ankle sprains are an extremely common injury; approximately 27,000 ankle sprains occur per day in America. Fifty percent of these can lead to a cartilage injury to the ankle. There has been a high quoted rate of failure with conservative measures of up to 45% in some series. Surgical options are largely broken down into 2 groups, namely, reparative or regenerative treatments. The reparative techniques include debridement and bone marrow stimulation techniques such as microdrilling and microfracture. Regenerative techniques include autologous osteochondral transplants. However, there are disadvantages in terms of donor site morbidity and the development of subchondral bone cysts over time. The aim of this video is to demonstrate a technique for microfracture and augmentation with bone marrow aspirate concentration and Tisseel fibrin glue. This video details the indications for performing microfracture, the indications for using bone marrow stimulation techniques, and the contraindications. Patient positioning, setup, preparation of the lesion, harvesting of the bone marrow aspirate concentrate, and application of the bone marrow aspirate are detailed.

Resection and reconstruction of pelvic and extremity soft tissue sarcomas with major vascular involvement: Current concepts.

Soft tissue sarcoma accounts for approximately 1% of all cancers diagnosed annually in the United States. When these rare malignant mesodermal tumours arise in the pelvis and extremities, they may potentially encase or invade large calibre vascular structures. This presents a major challenge in terms of safe excision while also leaving acceptable surgical margins. In recent times, the trend has been towards limb salvage with vascular reconstruction in preference to amputation. Newer orthopaedic and vascular reconstructive techniques including both synthetic and autogenous graft reconstruction have made complex limb-salvage surgery feasible. Despite this, limb-salvage surgery with concomitant vascular reconstruction remains associated with higher rates of post-operative complications including infection and amputation. In this review we describe the initial presentation and investigation of patients presenting with soft tissue sarcomas in the pelvis and extremities, which involve vascular structures. We further discuss the key surgical reconstructive principles and techniques available for the management of these complex tumours, drawn from our institution's experience as a national tertiary referral sarcoma service.

Avascular necrosis of the metacarpal head: a case of Dietrich's disease and review of the literature.

BACKGROUND: Isolated avascular necrosis of the metacarpal head, also known as Dietrich's disease, is a rare entity with few cases reported previously in the literature. It has been associated with steroid use, lupus, and trauma. We describe the clinical presentation, pathogenesis, and treatment options associated with this uncommon condition. CASE REPORT: A 36-year-old man presented with a 1-year history of a painful right middle finger metacarpophalangeal joint (MCPJ). There was no preceding history of trauma. Routine blood investigations and plain-film imaging were unremarkable. Magnetic resonance imaging (MRI) revealed a focus of osteonecrosis in the middle finger MCPJ consistent with Dietrich's disease. Given the patient's excellent functional status, conservative therapy was been successfully undertaken. CONCLUSIONS: Dietrich's disease, although a rare entity, must be considered in the differential diagnosis of painful MCPJ, where routine blood investigations and plain-film imaging studies are unremarkable.

Cost benefit analysis of the use of tranexamic acid in primary lower limb arthroplasty: A retrospective cohort study.

AIM: To examine the cost benefit conferred by the perioperative administration of intravenous tranexamic acid (TXA) in lower limb arthroplasty. METHODS: This study evaluates the use of TXA in 200 consecutive lower limb arthroplasties performed in a single surgeon series. The initial 100 patients (control group) underwent surgery without perioperative administration of TXA while the subsequent 100 patients (TXA group) all received 1 g TXA at the time of induction of anaesthesia. Pre- and post-operative haemoglobin, platelet count, haematocrit, the use of blood product post-operatively, length of stay were examined. A financial analysis of both groups was then undertaken. RESULTS: The mean age of patients in both groups was 63 ± 13 years. There were no significant differences between groups in terms of gender (P = 0.47), proportion of total hip replacement to total knee replacement (P = 0.25) or pre-operative haemoglobin (P = 0.43). In the control group, the transfusion rate was 22%. In the TXA group, the transfusion rate dropped to 2% (P < 0.001). The mean post-operative haemoglobin was 10.82 ± 1.55 g/dL in the control group vs 11.33 ± 1.27 g/dL in the TXA group (P = 0.01). The total cost of transfused blood products was €11055 and €603 respectively. The mean length of stay in the control group was 6.53 ± 5.93 d vs 5.47 ± 4.26 d in the TXA group (P = 0.15) leading to an estimated financial saving of €114586. There was one pulmonary embolus in the control group and one deep venous thrombosis in the TXA group. CONCLUSION: Intravenous TXA reduces blood loss in lower limb arthroplasty. This leads to lower transfusion rates, shorter length of stay in hospital and significant financial savings.