Aims. Leg length discrepancy (LLD) is a common pre- and postoperative issue in total hip arthroplasty (THA) patients. The conventional technique for measuring LLD has historically been on a non-weightbearing anteroposterior pelvic radiograph; however, this does not capture many potential sources of LLD. The aim of this study was to determine if long-limb EOS radiology can provide a more reproducible and holistic measurement of LLD. Methods. In all, 93 patients who underwent a THA received a standardized preoperative EOS scan, anteroposterior (AP) radiograph, and clinical LLD assessment. Overall, 13 measurements were taken along both anatomical and functional axes and measured twice by an orthopaedic fellow and surgical planning engineer to calculate intraoperator reproducibility and correlations between measurements. Results. Strong correlations were observed for all EOS measurements (r. s. > 0.9). The strongest correlation with AP radiograph (inter-teardrop line) was observed for functional-ASIS-to-floor (functional) (r. s. = 0.57), much weaker than the correlations between EOS measurements. ASIS-to-ankle measurements exhibited a high correlation to other linear measurements and the highest ICC (r. s. = 0.97). Using anterior superior iliac spine (ASIS)-to-ankle, 33% of patients had an absolute LLD of greater than 10 mm, which was statistically different from the inter-teardrop LLD measurement (p < 0.005). Discussion. We found that the conventional measurement of LLD on AP pelvic radiograph does not correlate well with long leg measurements and may not provide a true appreciation of LLD. ASIS-to-ankle demonstrated improved detection of potential LLD than other EOS and radiograph measurements. Full length, functional imaging methods may become the new gold standard to measure LLD. Cite this article: Bone Jt Open 2022;3(12):960–968

Aims. To evaluate mid-to long-term patient-reported outcome measures (PROMs) of endoprosthetic reconstruction after resection of malignant tumours arising around the knee, and to investigate the risk factors for unfavourable PROMs. Methods. The medical records of 75 patients who underwent surgery between 2000 and 2020 were retrospectively reviewed, and 44 patients who were alive and available for follow-up (at a mean of 9.7 years postoperatively) were included in the study. Leg length discrepancy was measured on whole-leg radiographs, and functional assessment was performed with PROMs (Toronto Extremity Salvage Score (TESS) and Comprehensive Outcome Measure for Musculoskeletal Oncology Lower Extremity (COMMON-LE)) with two different aspects. The thresholds for unfavourable PROMs were determined using anchor questions regarding satisfaction, and the risk factors for unfavourable PROMs were investigated. Results. The thresholds for favourable TESS and COMMON were 64.8 and 70.4 points, respectively. Multivariate analysis showed that age at surgery (p = 0.004) and postoperative leg length discrepancy (p = 0.043) were significant risk factors for unfavourable TESS results, while age at surgery (p < 0.001) was a significant risk factor for unfavourable COMMON-LE results. Following receiver operating characteristic analysis, the threshold for both TESS and COMMON-LE was 29 years of age at surgery. Additionally, a leg length discrepancy of 8.2 mm was the threshold for unfavourable TESS. Conclusion. Patients aged > 29 years at the time of surgery require appropriate preoperative counselling and adequate postoperative physical and socioemotional support. Reconstruction equivalent to the length of the resected bone can reduce the risk of functional disabilities in daily living. Cite this article: Bone Jt Open 2023;4(12):906–913

Originally used for correction of angular malalignment, 2 hole plate epiphyseodesis has recently gained popularity in paediatric orthopaedic practice for the correction of leg length discrepancy. In this study we aim to assess the efficiency of guided growth plates in correcting leg length discrepancy. Thirty-three children treated for leg length discrepancy with guided growth plates (“8-Plate”, Orthofix, Inc and “I-Plate”, Orthopediatrics) in a tertiary referral centre were retrospectively analysed. Medial and Lateral plates were inserted for symmetrical growth reduction and patients were followed up with clinical and radiological assessment. Thirty patients had distal femoral epiphyseodesis and three had proximal tibial epiphyseodesis. Leg lengths and individual bone lengths were measured from pre and post – operative radiographs. The angle between the screws was measured from radiographs taken intra operatively and at the time of final follow up to assess screw divergence with growth. Efficiency was calculated as the ratio of growth inhibition achieved to the projected discrepancy at maturity if left untreated. At a mean follow up of 17 months (4–30 m) leg length discrepancy improved from a mean of 30 mm (50–15mm) to 13 mm (2.5–39mm) (p < 0.01). The angle between screws increased from 6 degrees to 26 degrees over the follow up period. Efficiency was found to be 66%. There were 5 patients with angular deformity who needed plate removal and 2 patients developed superficial infection that responded to oral antibiotics. Epiphyseodesis using guided growth plates is an effective way to correct leg length discrepancy as it is a reversible procedure. Patients undergoing this treatment should be kept under close follow up to prevent development of angular malalignment. Inserting the screws in a divergent fashion at the outset may increase the effectiveness of this procedure

It has been well documented that leg length discrepancy can be associated with back, knee and hip problems. Less is known about the effect on the foot. The effect of a simulated leg length discrepancy on foot loading patterns and gait cycle times in normal individuals was investigated. Thirty feet of normal volunteers were evaluated using a ‘Musgrave Footprint Computerised Pedobarograph System’. Leg length discrepancy was simulated using flexible polyurethane soles of 1 to 5cm thickness, secured to the sole of a sandal worn on the opposite foot. Recordings of foot pressures and load were made barefoot (control) and then recordings were taken with simulated leg length discrepancies of 1 to 5cm. As leg length discrepancy increased, the total loading on the foot increased from 35. 31 to 37. 99 kg/cm²/sec, the forefoot loading increased from 15. 58 to 19 kg/cm²/sec, whereas hindfoot loading remained the same. Further analysis of forefoot loading revealed that all subjects except for female middle loaders demonstrated increased hallux loading as the leg length discrepancy increased (p< 0. 0001). Analysis of gait cycle time with increasing leg length discrepancy showed that the contact phase of gait decreased from a mean of 22% to 13% (p< 0. 0001), the midstance phase remained the same, whereas the propulsion phase increased from 44% to 50% (p< 0. 003). This study demonstrates for the first time that leg length discrepancy has manifest changes in the foot. When prescribing orthotics to address leg length discrepancy, orthopaedic surgeons should consider attempts to relieve the increased pressure on the 2nd and 3d metatarsal heads, or incorporate a metatarsal bar to decrease the time of metatarsal loading

Digital templating was used in 50 patients who underwent THA using Merge Ortho software, Cedara. Clinical examination was performed first, to measure leg lengths and account for pelvic obliquity and flexion deformity. Good quality digital radiographs were obtained with anteroposterior and lateral views extending beyond the tip of the femoral component and the cement restrictor. A coin was placed on the ASIS to help in determining radiological magnification. Digital radiographs were saved in DICOM format and imported to EndoMap software system. A 6-step technique was used for templating as follows:. Radiographic assessment; looking at the quality of bone, amount of bone stock, dysplasia, osteophytes, and other abnormalities. Correction of magnification; following the specific instructions of the software, by measuring the diameter of the coin on the digital radiograph. 3. Measuring leg length discrepancy; the software system automatically calculated the leg length discrepancy, even in the presence of pelvic obliquity (Figure1). 4. Templating acetabular component; the desired cup was selected from the implant library after identifying important landmarks. The size and position was modified to fit the acetabulum and to restore the center of rotation of the hip, considering minimal bone removal and sufficient bone coverage laterally. Templating femoral component; the size and position of the desired stem was adjusted to fit the femoral canal, different offsets were compared to find the best match for the patient's original offset. Correction of leg length discrepancy and measuring length of neck resection; the height of the femoral stem was adjusted to correct any leg length discrepancy by placing the center of the head above the center of the cup by the same length of discrepancy. Then the level of the neck resection was marked at the level of the stem collar and the femoral neck cut was measured by a digital ruler from the tip of the lesser trochanter to the mark of neck resection. In case of leg length discrepancy, the height of the femoral neck cut was adjusted accordingly to compensate for the leg length discrepancy. For example, if the affected leg is 20 mm short, place the centre of the head 20 mm above the centre of the cup. Intraoperatively, the surgeon performed the femoral neck osteotomy at the level determined by preoperative templating. Postoperatively, the leg length was measured and compared to the preoperative leg length. Preoperatively, the leg length discrepancy ranged from 5 to 30 mm. In all cases, the leg was short on the side of THR (ipsilateral). Leg length discrepancy was adjusted in all THR cases. Postoperatively, the accuracy of the correction was found to be within 5 millimeters i.e. less than 5mm of shortening or lengthening). Intraoperatively, the level of femoral neck cut ranged from 1 to 44 mm. Digital templating is useful in adjusting leg length discrepancy. In addition, there were other benefits such as predication of femoral and acetabular implant sizes, restoration of normal hip centre, and optimization of femoral offset

Purpose of the study: Perception of leg length discrepancy after total hip arthroplasty (THA) is a source of patient dissatisfaction. We followed 100 patients with firstintention THA to determine the clinical significance of radiological leg length discrepancy of less than 15 mm. Materials and Methods: An investigator blinded to the clinical context measured radiological leg length discrepancy in 100 patients after THA. Another investigator evaluated the clinical perception of leg length discrepancy in the same patients 15 days, one month, three months and one year after implantation of their THA. Results: At 15 days, 73 patients had a clinical perception of leg length discrepancy; 48 at one month; 24 at three months; and 15 at one year. Although the 15 patients (15%) presented leg length discrepancy greater than 10 mm (but less than 15 mm), only four still perceived this difference at one year. At one year, there was no correlation between the length of the discrepancy and clinical perception by the patient. When patients had a length discrepancy greater than 10 mm (but less than 15 mm), the probability of perceiving the difference clinically was not greater (p> 0.05) than for patients whose leg length discrepancy was less than 10 mm. Conversely, patients who perceived a leg length discrepancy at one year had significantly more pronounced (p=0.02) spinal disorders and more permanent hip flexion. Discussion: Perception of leg length discrepancy is a frequent complaint postoperatively, but rare at one year, even when the radiological difference reaches 15 mm. At one year, the perception of leg length discrepancy is not correlated with the radiological difference but rather with the degree of spinal disorder or permanent hip flexion. Conclusion: Navigation would have a modest effect on this problem which is probably related in part to spinal rehabilitation

The Dall approach is a modified anterolateral approach with osteotomy of the anterior part of the greater trochanter. This approach relatively preserves the soft tissue tension during total hip arthroplasty (THA). We insert the stem and select a ball neck size so as to have a stable hip which will not dislocate easily during the trial reduction. The aim of this study is to evaluate the adequacy of this method, to measure leg length discrepancy and offset discrepancy at postoperative radiographs. We selected patients for inclusion in this study from those who have more than a 120 degree of affected hip flection angle, the opposite hip is almost normal with a low leg length discrepancy (primary OA, osteonecrosis, Crowe 1 secondary OA, femoral neck fracture). All THA were performed with cement fixation using an alignment guide to ensure accurate acetabular positioning. The ball head's diameter used were all 26mm. From September 2011 to October 2013, 22 patients met inclusion criteria among 103 THA. The mean age for 22 subjects was 66.6±12 years. The mean flexion angle of preoperative hip joints was 127.2±6.1 degrees. The cup inclination was 43.8° ± 3.5°. Anteversion was 11.8°±6°. The mean preoperative leg length discrepancy was 5.8mm±6.3mm. The mean postoperative leg length discrepancy was 0.7±3.5mm. The mean postoperative offset discrepancy was 0.7±6.6mm. There were no dislocations in this series of 103 cases. Discussion. Dislocation and leg length discrepancies are major complications following a total hip arthroplasty. A good range of motion of the preoperative hip joint is considered a high risk dislocation factor. The Dall approach with minimal release of soft tissue related to a tension of hip joint offers maximal stability and the ability to accurately restore leg length

The results of total hip arthroplasty (THA) revisions to correct leg length discrepancy (LLD) are not clear, with only two former limited series (< 25 patients). Therefore, we conducted a retrospective study of THA revisions for LLD to determine: 1) the change in LLD, 2) the function outcomes and whether obtaining equal leg lengths influenced function, 3) the complication and survival rates. This multicenter study included 57 patients: 42 THA revisions for limb shortening and 15 revisions for limb lengthening. LLD was measured on conventional radiographs and EOS. The Oxford-12 and FJS outcome scores were collected and the number of patients achieving the Oxford-12 MCID. The revisions were carried out a mean of 2.8 years after the index THA. The median LLD decreased from 7.5 mm (IQR: [5;12]) to 1 mm (IQR: [0.5;2.5]) at follow-up (p=0.0002). Overall, 55 of 57 patients (96%) had < 5 mm LLD at follow-up and 12 patients (21%) had equal leg lengths. The complication rate was 25%: 12 mechanical complications (8 periprosthetic femoral fractures, 2 stem loosening and 1 cup loosening, 1 dislocation) and 1 periprosthetic infection. The patient satisfaction was high with a median FJS of 79.2/100 and 77% of patients reached the Oxford-12 MCID. Lengthening procedures had significantly worst function than shortening (38% vs 91% of patients achieving the Oxford-12 MCID (p=0.0004)). Survivorship was 85% (95% CI: 77.9 – 92.5) at 2 years and 77% (95% CI: 66.3 – 87.1) at 4.6 years when using re-revision for any reason as the endpoint. When LLD after THA does not respond to conservative management, revision THA should be considered. Although revision THA for LLD improved medium-term functional outcomes with a high patient satisfaction rate, especially for shortening procedures, the complication rate was high, particularly related to periprosthetic femoral fracture

Aims: Leg length discrepancy is a well-recognised complication after total hip arthroplasty. However, the effect of using a cemented or uncemented femoral component on leg length has not been previously investigated. The aim of our study was to assess leg length discrepancy following total hip arthroplasty using a cemented femoral component and to compare this with an uncemented femoral component. Patients and method: We included 140 patients who had undergone a primary total hip arthroplasty in our study. All patients received an uncemented Duraloc acetabular cup (Depuy, Leeds, UK). Our uncemented group consisted of 70 consecutive patients who had received an uncemented Accolade femoral prosthesis (Depuy, Leeds, UK). Our cemented group included 70 patients who had received a cemented Ultima femoral prosthesis (Depuy, Leeds, UK). Leg lengths were measured from radiographs by two independent observers using a validated assessment method, pre-operatively and at six months post-operatively. Clinical outcome was assessed using Harris hip scores. Results: The mean age of the patients was 68 years for the uncemented group and 56 years for the cemented group. The overall leg length discrepancy was mean 5.7mm (range 0 to 26mm). The uncemented group had an increase in leg length discrepancy post-operatively compared to the cemented group (6.4mm vs 4.2mm), p< 0.05. There was no significant difference in Harris hip scores between the uncemented and cemented groups either pre-operatively (37.4 vs 38.7) or at 6 months postoperatively (77.9 vs 78.7 respectively). Conclusion: We found a significant increase in leg length discrepancy after total hip arthroplasty using an uncemented femoral prosthesis compared with a cemented femoral prosthesis. This was detectable radiologically but did not affect clinical outcome. Patients should be informed about the risk of leg length discrepancy before total hip arthroplasty particularly if an uncemented femoral prosthesis is used

Our aim was to use CT Scanogram to evaluate fibular growth, and thus calculate normal growth velocity, which may aid in determining the timing of epiphysiodesis. Current understanding of normal lower limb growth and growth prediction originates in the work of Anderson et al published in the 1960s. There now exist several clinical and mathematical methods to aid in the treatment of leg length discrepancy, including the timing of epiphysiodesis. Early research in this area provided limited information on the growth of the fibula. It is now well recognized that abnormal growth of paired long bones may evolve into deformity of clinical significance. Existing work examining fibular growth used plain film radiography only. Computed Tomography (CT) scanogram is now the preferred method for evaluating leg length discrepancy in the paediatric population. We calculated fibular growth for 28 children (n = 28, 16 girls and 12 boys) presenting with leg length discrepancy to our unit. Mean age at presentation was 111.1 months (range 33 – 155 months). For inclusion, each child had to have at least five CT scanograms performed, at six monthly intervals. Fibular length was calculated digitally as the distance from the proximal edge of the proximal epiphysis to the most distal edge of the distal epiphysis. For calculation purposes, mean fibular length was determined from two measurements taken of the fibula. A graph for annual fibular growth was plotted and fibular growth velocity calculated. CT Scanogram may be used to calculate normal fibular growth in children presenting with leg length discrepancy

Leg length discrepancy (LLD) is a recognised complication of total hip arthroplasty. LLDs can cause abnormal weight bearing, leading to increased wear, aseptic loosening of replacement hips and pain. To compensate for LLDs the patient can either flex the knee of the long leg or tilt their pelvis. The aim of this project was to investigate how stance affects static limb loading of patients with leg length discrepancy. A pedobarograph was used to measure the limb loading of 20 normal volunteers aged 19 to 60. A 2 second recording with both feet on was taken to establish their body weight. Readings were taken of the left foot with the right level, 3.5cm lower (simulating a long left leg) and 3.5cm higher. In each case three readings were taken with the knee flexed and three readings with the knee extended. When both feet were at the same level, the left limb took 54% of the load. When the right foot was lower and the left knee flexed, the left leg took 39 % of the load (P < 0.001) (paired t-test). When the left knee was extended the left leg took 49 % of the load (P = 0.074). With the right foot higher and right knee flexed, the left leg took 65 % of the load (P < 0.001). When the right knee was extended the left leg took 58 % of the load (P = 0.069). These results show that weight distribution is increased in the simulated shorter limb. Loading is greater when the longer limb is flexed. Tilting the pelvis reduced the load. However this may cause pelvic and spinal problems. Uneven load distribution is likely to lead to early fatigue when standing and may explain why some post arthroplasty patients with limb length discrepancy have poor outcomes

Background. Leg length discrepancy (LLD) after intramedullary nailing of femoral shaft fractures is a common problem reported in up to 43% of cases. Comminuted fractures with radiographic loss of bony landmarks have an increased possibility of being fixed with unequal leg lengths. Aims. The purpose of this report is to evaluate the efficacy of routinely obtaining a CT scanogram post-operatively on patients of comminuted femoral shaft fractures treated with intramedullary nailing and immediate correction of limb length inequality if indicated. Results. Twenty one patients with comminuted femoral shaft fractures that were treated with intramedullary nailing and underwent a CT scannogram for evaluation of LLD were included in the study. There were 12 patients with Winquist III and 9 with a Winquist IV fracture pattern. Following surgery leg lengths were measured from the CT scanograms using a computerised measuring ruler. The largest leg length discrepancy noted on scannogram was 4 cm. The average limb length discrepancy was 0.67 cm. Eight patients had a discrepancy of 1cm or greater. We also measured the tibial length in all patients and found only 3 patients with exactly equal tibial lengths. A tibial length discrepancy less than 5mm was observed in 11 patients. In 7 patients it was between 5-9mm and in 3 patients it was 10mm or greater. Four patients underwent leg length correction during the same admission. Conclusion. The decision to undertake correction of the LLD is primarily dependant on the degree of discrepancy. The degree of LLD that requires correction remains undefined. In this study LLD of greater than 15mm was considered for equalisation. Immediate equalisation saves cost, morbidity, delayed sequelae and litigation. Tibial length discrepancy may contribute to the total leg length discrepancy and requires consideration. We recommend a post-operative scanogram costing $380 in patients of comminuted femoral shaft fractures treated with intramedullary nailing

Aims. Temporary epiphysiodesis (ED) is commonly applied in children and adolescents to treat leg length discrepancies (LLDs) and tall stature. Traditional Blount staples or modern two-hole plates are used in clinical practice. However, they require accurate planning, precise surgical techniques, and attentive follow-up to achieve the desired outcome without complications. This study reports the results of ED using a novel rigid staple (RigidTack) incorporating safety, as well as technical and procedural success according to the idea, development, evaluation, assessment, long-term (IDEAL) study framework. Methods. A cohort of 56 patients, including 45 unilateral EDs for LLD and 11 bilateral EDs for tall stature, were prospectively analyzed. ED was performed with 222 rigid staples with a mean follow-up of 24.4 months (8 to 49). Patients with a predicted LLD of ≥ 2 cm at skeletal maturity were included. Mean age at surgery was 12.1 years (8 to 14). Correction and complication rates including implant-associated problems, and secondary deformities as well as perioperative parameters, were recorded (IDEAL stage 2a). These results were compared to historical cohorts treated for correction of LLD with two-hole plates or Blount staples. Results. The mean LLD was reduced from 25.2 mm (15 to 45) before surgery to 9.3 mm (6 to 25) at skeletal maturity. Implant-associated complications occurred in 4/56 treatments (7%), and secondary frontal plane deformities were detected in 5/45 legs (11%) of the LLD cohort. Including tall stature patients, the rate increased to 12/67 legs (18%). Sagittal plane deformities were observed during 1/45 LLD treatments (2%). Compared to two-hole plates and Blount staples, similar correction rates were observed in all devices. Lower rates of frontal and sagittal plane deformities were observed using rigid staples. Conclusion. Treatment of LLD using novel rigid staples appears a feasible and promising strategy. Secondary frontal and sagittal plane deformities remain a potential complication, although the rate seems to be lower in patients treated with rigid staples. Further comparative studies are needed to investigate this issue. Cite this article: Bone Joint J 2021;103-B(8):1428–1437

Aims

This study aimed to investigate the incidence of ≥ 5 mm asymmetry in lower and whole leg lengths (LLs) in patients with unilateral osteoarthritis (OA) secondary to developmental dysplasia of the hip (DDH-OA) and primary hip osteoarthritis (PHOA), and the relationship between lower and whole LL asymmetries and femoral length asymmetry.

In 90 patients undergoing primary THA, leg length discrepancy (LLD) and hip function were assessed pre-operatively and 3 and 12 months postoperatively. Hip function was measured by the Oxford hip score (OHS). Postoperatively the mean OHS improved by 26 points out of a possible 48 at 3 months and by 30 points at 12 months. Postoperatively 62% of patients’ limbs were lengthened by a mean of 9 mm. The LLD was perceived by 43% of the affected patients at 3 months and by 33% at 12 months. The OHS in patients who perceived true lengthening was 27% worse than in the other patients at 3 months and 18% worse at 12 months. In 98%, lengthening occurred in the femoral component. The problem of LLD after THA is lengthening. Appropriate placement of the femoral component could reduce patients’ perception of this

Introduction and aims: Leg length discrepancy (LLD) after total hip arthroplasty (THA) has been associated with a number of complications. The aim of this study was to assess the influence of LLD on the outcome of THA by comparing patients’ perception and their Oxford Hip Score with their anatomical leg length. A secondary aim was to identify the site at which LLD was created intraoperatively. Methods: LLD and hip function were assessed in 90 patients undergoing primary total hip arthroplasty before and 3 months after surgery. Hip function was measured by the Oxford Hip Score (OHS). We measured leg length on pre- and postoperative radiographs and the position of the centre of rotation and the stem length on the postoperative radiographs. Results: Post operatively 62% of patients’ limbs were lengthened by a mean of 9 mm. This was perceived by 43% of the lengthened patients. The OHS in patients who perceived true lengthening was 27% worse than the rest of the population. In 98%, lengthening occurred in the femoral component. 20% perceived true shortening and their OHS was not affected. Conclusion: The problem of LLD after THA is lengthening. Accurate placement of the femoral component and especially avoiding overlengthening could significantly reduce patients’ perception of this

Objectives: We aimed to assess the incidence of requirement for shoe raises for a leg length discrepancy (LLD) after total hip replacement (THR). We also assessed the patient satisfaction with, and continued use of shoe raises for symptomatic LLD after THR. Methods: We searched the orthotics records at our institution to identify all patients who had required a shoe raise for symptomatic LLD after primary unilateral total hip replacement between January 2003 and October 2008. 75 patients were identified. 72 were still alive. In the same period 4270 primary hip replacements were carried out at the institution. A questionnaire was sent out to all living patients. Patient details (including satisfaction) and operative details were recorded. Pre-operative and post-operative radiological measurements of leg length discrepancy (LLD) were performed. Results: The incidence of requirement of a shoe raise for LLD after THR at our institution was 1.8%. 68% were women. 84% of questionnaires were returned. 31% had stopped using their shoe raise completely. Two-thirds of patients found the raise improved their symptoms of a LLD. Symptoms causing dissatisfaction with the shoe raise included new or worsening back pain, limp, uneven walking, self awareness, need to adjust trouser length, pain in other hip, discomfort while walking, and difficulty buying shoes. Patient overall satisfaction with their THR was poor in the patients who were dissatisfied with the shoe raise, but was good in those who found the raise useful. Conclusion: About 2% of patients may require a shoe raise for symptomatic LLD after THR. Of these 65% will find the shoe raise helpful. Patient with a LLD after a THR that is not helped by a shoe raise are very dissatisfied. It is important that surgeons should take great care to avoid causing a LLD after THR as it can be a cause of very low patient satisfaction

Introduction. Many authors have described component position and leg length discrepancy (LLD) after total hip arthroplasty (THA) as the most important factors for good postoperative outcomes. However, regarding the relationships between component position and different approaches for THA, the optimal approach for component position and LLD remains unknown. The aims of this study were to compare these factors among the direct anterior, posterolateral, and direct lateral approaches on postoperative radiographs retrospectively, and determine which approach leads to good orientation in THA. Methods. We retrospectively evaluated 150 patients who underwent unilateral primary THA in our department between January 2009 and December 2014, with the direct anterior, posterolateral, or direct lateral approach used in 50 patients each. Patients with significant hip dysplasia (Crowe 3 or 4), advanced erosive arthritis, prevented osteotomy of the contralateral hip, and body mass index (BMI) of more than 30 were excluded. The mean age, sex, and preoperative diagnosis of the affected hip were equally distributed in patients who underwent THA with the different approaches. The mean BMI did not differ significantly among the groups. The radiographic measurements included cup inclination angle, dispersion of cup inclination from 40°, and LLD on an anteroposterior pelvic radiograph, and cup anteversion angle and dispersion of cup anteversion from 20° on a cross-table lateral radiograph postoperatively. We also measured the ratios of patients with both cup inclination of 30–50° and cup anteversion of 10–30° (target zone in our department), femoral stem varus/valgus, and LLD of 10 mm or less. Statistical analyses used an unpaired t-test and Fisher's exact test, with significance set at p<0.05. Results. The mean cup inclination was 36.9±5.1° for direct anterior approach, 40.8±7.5° for posterolateral approach, and 38.5±7.5° for direct lateral approach. Dispersion of cup inclination from 40° was almost identical in the three groups, with no significant differences. The mean cup anteversion was 23.4±5.5° for direct anterior approach, 25.9±9.2° for posterolateral approach, and 24.3±8.6° for direct lateral approach. Dispersion of cup anteversion from 20° differed between direct anterior approach and posterolateral or direct lateral approach (P<0.05 for each). The mean LLD was 1.3±6.6mm for direct anterior approach, 3.0±8.6mm for posterolateral approach, and 2.6±7.4mm for direct lateral approach. The mean LLD did not differ significantly among the three groups. The ratio of patients with both cup inclination of 30–50° and cup anteversion of 10–30° was significantly better for direct anterior approach than for posterolateral or direct lateral approach (78% vs. 52% and 52%, respectively; p<0.05). The ratios of femoral stem varus/valgus and LLD of 10 mm or less did not differ among the groups. Conclusions. The direct anterior approach in THA appeared to have small dispersion of cup anteversion angle and high ratio of cup component position in our target zone compared with the posterolateral and direct lateral approaches. However, the LLD and femoral stem varus/valgus after THA did not differ significantly among the three approaches postoperatively

Introduction: Leg length discrepancy (LLD) following total hip arthroplasty (THA) can lead to disappointed patients, increased dislocation, increased wear and suboptimal function. It is one of the commonest reasons for litigation following THA in the United States. The purpose of this study was to radiologically and functionally assess the efficacy of a simple technique for intra-operative leg length assessment during THA via a posterior approach. Materials & Methods: This technique was undertaken in 50 consecutive THAs. The pre-and 3 month postoperative LLD was measured on standing AP pelvis radiographs. The results were compared with 50 THAs performed by the same surgeons without using the technique. Pre-and post-operative OHS and UCLA scores were recorded in both groups. Results: In the control group the mean pre- and postoperative LLD was 9.38 mm and 7.75mm respectively. In the new technique group the mean pre-operative LLD was 11.37 and the post-operative LLD was 1.70mm. The final LLD was significantly less in the new technique group (p< 0.001). Fifteen patients in the control group and three patients in the new technique group had post–operative lengthening. Oxford Hip and UCLA score improvement in new technique group was greater than in the control group (p< 0.05). Discussion: The technique we introduced to assess leg length intra-operatively has shown to be safe, reliable and accurate. We have nonetheless demonstrated much greater accuracy at providing equal leg lengths and improved functional outcome using this new technique

Objective. In total hip arthroplasty (THA), the femoral component influences leg length inequality and gait, and is associated with poor muscle strength and other unsatisfactory long-term results. We have therefore used intraoperative radiographs to acquire accurate measurements of femoral component size and position. At the last meeting of this society, we reported that accurate positioning was successfully achieved in 68 cases (87.2%) as a consequence of taking intraoperative radiographs. However, we have little understanding as regards to the accuracy of X-ray measurements. We accordingly undertook an examination of the accuracy of such measurements. The purpose of this study was to evaluate the difference between leg length discrepancy (LLD) measured using X-ray and computed tomography (CT). Materials and Methods. The study group comprised 48 primary THAs performed between October 2010 and April 2012. Using 2D template software (JMM Corporation), we measured LLD using pre-operative anteroposterior (AP) radiographs of the pelvis. On the basis of both teardrop lines, we measured LLD of the lesser trochanter top (Fig. 1), lesser trochanter direct top (Fig. 2), and trochanteric top (Fig. 3). Furthermore, using Aquarius NET software, we measured LLD using AP and lateral scout views of the pelvis and bilateral femurs. This data was defined as the true LLD. The difference between the X-ray data (lesser trochanter top, lesser trochanter direct top, and trochanteric top) and the CT data was defined as accuracy. Additionally, we measured the size of the lesser trochanter and examined the association. Results. The mean LLD was 11.4, 12.1, and 9.6 mm on the lesser trochanter top, the lesser trochanter direct top, and the trochanteric top of radiographs, respectively, and 11.6 mm on CT scans. Precision was within 5 mm of the true LLD in 42 cases (87.5%) for the lesser trochanter top, 36 cases (75.0 %) for the lesser trochanter direct top, and 27 cases (63.0%) for the trochanteric top. We observed no association between the size of the lesser trochanter and the measurement accuracy. Conclusions. When using X-ray measurements, the lesser trochanter top is the most useful site for LLD measurement