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Objective: Closed reduction and dynamic hip screw (DHS) osteosynthesis are preferred as joint‐preserving therapy in case of medial femoral neck fractures (MFNFs). A change in the femoral offset (CFO) can cause gait abnormality, impingement, or greater trochanteric pain syndrome. It is unknown whether the femoral offset (FO) can be postoperatively fully restored. The aim of the study was to investigate the extent of a possible CFO in hip joints after DHS osteosynthesis in the case of an MFNF. Methods: In this retrospective study, 104 patients (mean age: 71.02 years, men: n = 50, women: n = 54) with MFNF who underwent closed reduction and DHS osteosynthesis were analyzed by postoperative x‐rays to assess CFO between the operated (OS) and nonoperated joint side (NOS). The studies covered the time period 2010–2020. A statistical comparison was performed between the mean values of FO between OS and NOS, taking into account patient age, gender, and fracture severity. Results: All operated hip joints showed a CFO. In 76.0% (79 of 104), the FO decreased (FOD), and in 24.0% (25 of 104), the FO increased (FOI). A critical CFO (>15% CFO) was detected in 52.9% (55 of 104). In hip joints with postoperative FOD, the mean FO between NOS (49.15 mm [±6.56]) and OS (39.32 mm [±7.87]) and in hip joints with postoperative FOI the mean FO between NOS (41.59 [±8.21]) and OS (47.27 [±6.68]) differed significantly (p < 0.001). Preoperative FO (rS: −0.41; p > 0.001) and caput–collum–diaphyseal angle (CCD; rS: 0.34; p > 0.001) correlated with postoperative CFO. FOD was found in hip joints with a preoperative FO >44 mm and CCD <134° vice versa FOI in hip joints with a preoperative FO <44 mm and CCD >134°. Conclusion: Closed reduction and DHS osteosynthesis in patients with MFNF result in a clustered significant CFO. The individual FO should be taken into account pre‐ and intraoperatively to avoid a postoperative extensive CFO. [ABSTRACT FROM AUTHOR]

Trochanteric bursitis (TB) is a prevalent complication following total hip arthroplasty (THA), with increased offset hypothesized as a potential risk factor. This study investigated potential TB predictors in THA patients, including radiographic measurements of offset and leg length, comorbidities, and patient characteristics. In this retrospective cohort study, all THA patients from a single academic tertiary care center between 2005 and 2021 were reviewed. Exclusion criteria included less than one-year follow-up, osteonecrosis, or fracture. Manual radiographic measurements of offset (acetabular, femoral, and total) and leg length from preoperative and postoperative antero-posterior pelvis X-rays were taken, with scaling using femoral cortical diameter. Univariable and multivariable Cox proportional hazard models were employed to estimate TB risk. Of 1,094 patients, 103 (9.4%) developed TB, with a median (Q1, Q3) time to presentation of 41.8 weeks (25.5, 66.9). In univariable models, only sex was associated with increased TB risk, with women exhibiting a 1.79 times increased risk (hazard ratio: 1.79 (1.16, 2.76), P =.009). Changes in acetabular offset, femoral offset, total offset, and leg length between preoperative and postoperative radiographs were not associated with an increased risk of developing TB in the univariate or multivariate models. Furthermore, various offset thresholds were evaluated, with no amount of increased offset showing increased TB risk. This study found no relationship between femoral, acetabular, or total offset and TB following THA. These findings suggest that surgeons may consider adding offset for increased prosthetic stability in high-risk cases. However, given that this is a retrospective study, the authors are not advocating for the routine use of increased offset. The study identified women as a risk factor with a 1.79 times higher TB risk, highlighting the importance of counseling women patients on this heightened risk. [ABSTRACT FROM AUTHOR]

Objective Closed reduction and dynamic hip screw (DHS) osteosynthesis are preferred as joint‐preserving therapy in case of medial femoral neck fractures (MFNFs). A change in the femoral offset (CFO) can cause gait abnormality, impingement, or greater trochanteric pain syndrome. It is unknown whether the femoral offset (FO) can be postoperatively fully restored. The aim of the study was to investigate the extent of a possible CFO in hip joints after DHS osteosynthesis in the case of an MFNF. Methods In this retrospective study, 104 patients (mean age: 71.02 years, men: n = 50, women: n = 54) with MFNF who underwent closed reduction and DHS osteosynthesis were analyzed by postoperative x‐rays to assess CFO between the operated (OS) and nonoperated joint side (NOS). The studies covered the time period 2010–2020. A statistical comparison was performed between the mean values of FO between OS and NOS, taking into account patient age, gender, and fracture severity. Results All operated hip joints showed a CFO. In 76.0% (79 of 104), the FO decreased (FOD), and in 24.0% (25 of 104), the FO increased (FOI). A critical CFO (>15% CFO) was detected in 52.9% (55 of 104). In hip joints with postoperative FOD, the mean FO between NOS (49.15 mm [±6.56]) and OS (39.32 mm [±7.87]) and in hip joints with postoperative FOI the mean FO between NOS (41.59 [±8.21]) and OS (47.27 [±6.68]) differed significantly (p 0.001) and caput–collum–diaphyseal angle (CCD; r S: 0.34; p > 0.001) correlated with postoperative CFO. FOD was found in hip joints with a preoperative FO >44 mm and CCD 134°. Conclusion Closed reduction and DHS osteosynthesis in patients with MFNF result in a clustered significant CFO. The individual FO should be taken into account pre‐ and intraoperatively to avoid a postoperative extensive CFO.

Background/Objectives: Various parameters, like femoral offset and leg length, are associated with good patient outcomes after total hip arthroplasty. In this prospective study, the effects of stem design, its placement in the proximal femur and the resulting femoral offset on the total leg axis were investigated. Methods: The 27 patients included in this study received biplanar radiography (EOS®, EOS Imaging) with 3D reconstruction using sterEOS® both preoperatively and postoperatively. For all leg alignment parameters obtained from the 3D reconstruction and from measurements using mediCAD, the deltas between the postoperative and preoperative values were determined. Patients were divided into those who received a short-stem prosthesis and those who received a straight-stem prosthesis. Results: The change in femoral offset with the implantation of a short-stem prosthesis was significantly greater than that with the implantation of a straight-stem prosthesis (11.4 ± 5.9 vs. 4.6 ± 7.4 mm, p = 0.014). Compared with the straight-stem implantation, short-stem implantation caused a significantly greater increase in the varus orientation of the leg (−1.4 ± 0.9 vs. −0.4 ± 1.4°, p = 0.048). There was no significant difference in the positioning of the short-stem prosthesis compared to the straight-stem prosthesis in the proximal femur (3.6 ± 3.1 vs. 2.6 ± 1.9°, p = 0.317). Conclusions: These findings substantiate the impact of prosthesis design on offset and leg alignment. The implantation of short-stems is more variable and requires precise planning. Intraoperative non-physiological offset changes and varus deviation of the leg axis should be avoided. Trial registration: This study was retrospectively registered with the German Clinical Trials Register (DRKS) under the number DRKS00015053 on the 1 August 2018. [ABSTRACT FROM AUTHOR]

Background: Biomechanical reconstruction of the hip significantly impacts the clinical outcome and implant survival. Our knowledge is limited of the ability of neck-stabilised prostheses to restore hip biomechanics. We hypothesised that hip biomechanics, specifically leg length and global offset (GO), may be restored to an acceptable range using the Primoris™ stem. Methods and material: In this retrospective study, we analysed 152 patients who underwent total hip replacement (THA) using the short collum-fixated stem Primoris™. The primary outcomes were hip parameters measured by x-ray following THA using the Primoris™ stem. After surgery, the biomechanical parameters used were measured at the arthroplasty and the native contralateral side of the same x-ray. The X-rays were taken one year after the patient's surgery. 1. GO. 2. Leg length discrepancy (LLD). 3. Neck shaft angle (NSA). Results: We recorded an average GO of -3.4 mm (standard deviation (SD) 7.2) and an average LLD of +3.8 mm (SD 6.4). Furthermore, we registered an average 14-degree NSA increase (SD 7.4). Conclusion: The Primoris™ neck-stabilised stem enabled hip anatomy restoration to a favourable range with respect to GO and LLD as the average difference fell within ±5 mm. However, the stem tended to be implanted in valgus. [ABSTRACT FROM AUTHOR]

Purpose: Lateralized stems in primary cementless total hip arthroplasty (THA) showed to be associated with aseptic femoral loosening. However, femoral head length also affects femoral offset but was not considered so far. This study analyzed the impact of high femoral offset (hFO) combinations, formed by lateralized stems or large femoral head lengths, on aseptic femoral component loosening. Methods: Retrospective cohort study was performed including all patients that underwent primary cementless THA at our institution between July 2004 and December 2016. Patients were screened for aseptic femoral component loosening and grouped in aseptic loosening (AL) and non-aseptic loosening (nAL) group. Medical records were screened; implant details were noted and classified in hFO and standard femoral offset (sFO) combinations. Supposed risk factors for aseptic loosening were analyzed. Results: Two thousand four hundred fifty-nine THA could be included, containing 14 THA (0.6%) with aseptic femoral component loosening. The AL group contained 11 hFO combinations (78.6%), whereas in the nAL group, 1315 hFO combinations (53.8%) were used. Subgroup analysis showed significant difference between two groups for hFO combinations (p = 0.014), age (p = 0.002), NSAR (p = 0.001), and bilateral THA on same day (p = 0.001). The multiple logistic regression analysis showed that hFO combination was the only variable for increased probability of aseptic loosening (OR, 3.7; p = 0.04). Conclusion: High femoral offset combinations, formed by lateralized stems or large femoral head lengths in our collective of standard straight stems implanted by an anterior approach, show a 3.7-fold increased probability for aseptic femoral component loosening. Adjustment of the postoperative protocol may be considered in these cases to ensure proper stem ingrowth. [ABSTRACT FROM AUTHOR]

Background: Positioning implant components and restoring patient anatomy during total hip arthroplasty (THA) are essential for joint stability, polyethylene liner wear, and range of motion. Previous studies comparing intraoperative fluoroscopy with no fluoroscopy during the posterior or posterolateral approach have reported conflicting results. This meta-analysis evaluated if intraoperative fluoroscopy improves component positioning and femoral component position compared to no fluoroscopy during posterior or posterolateral approach total hip arthroplasty. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards were followed when conducting the systematic review. We searched Web of Science, Embase, PubMed, Cochrane Controlled Trials Register, Cochrane Library, Highwire, CBM, CNKI, VIP, and Wanfang database in May 2023 to identify studies involving Intraoperative fluoroscopy versus no fluoroscopy during posterior or posterolateral approach total hip arthroplasty. Finally, we identified 1133 patients (1145 hips) assessed in seven studies. Results: There were no significant differences in terms of acetabular cup inclination angle (ACIA, P = 0.43), ACIA within safe zone rate (P = 0.58), acetabular cup anteversion angle (ACAA, P = 0.46); ACAA within safe zone rate (P = 0.72), Combined safe zone rate (P = 0.28), dislocation rate (P = 0.64) and infection rate (P = 0.94) between two groups. Compared with the no fluoroscopy group, the intraoperative fluoroscopy group had more operation time (P < 0.00001), less femoral component offset difference (FCOD, P = 0.03), and less LLD (P < 0.00001). Conclusion: Even though intraoperative fluoroscopy was not related to an improvement in cup location or dislocation incidence. Our findings demonstrate that the restoration of leg lengths and femoral offset can be significantly improved by using intraoperative fluoroscopy to supplement good surgical skills in THA. The advantages of intraoperative fluoroscopy might become more apparent for surgeons with less experience. To ascertain whether intraoperative fluoroscopy for posterior or posterolateral approach total hip arthroplasty will have clinical benefits and improve the survival of prostheses, more well-powered and well-designed long-term follow-up studies were necessary. [ABSTRACT FROM AUTHOR]

The dislocation rate after total hip arthroplasty for osteonecrosis of the femoral head is higher than that after total hip arthroplasty for osteoarthritis. However, few reports have investigated the factors contributing to dislocation after total hip arthroplasty for osteonecrosis of the femoral head. The aim of this study was to assess radiological factors associated with posterior dislocation after total hip arthroplasty for osteonecrosis of the femoral head. We retrospectively reviewed 179 cementless total hip arthroplasties for osteonecrosis of the femoral head using a posterolateral approach between 2002 and 2020 with a minimum follow-up period of 24 months. The following radiological factors were examined for a possible association with posterior dislocation after total hip arthroplasty: cup anteversion angle, cup inclination angle, femoral offset, and stem anteversion angle. Posterior dislocation occurred in seven hips (3.9 %). Compared to hips without posterior dislocation, those with posterior dislocation exhibited a significantly smaller cup anteversion angle (p = 0.045) and a nonsignificantly greater decrease in femoral offset (p = 0.089). Based on receiver operating characteristic curve analyses, the cutoff values for predicting posterior dislocation were 9.9° for the cup anteversion angle and 8.1 mm for the decrease in femoral offset. Logistic regression analysis showed a significantly higher risk of posterior dislocation among hips with a cup anteversion angle less than 9.9° (odds ratio = 7.1, p = 0.022) or with a decrease in femoral offset over 8.1 mm (odds ratio = 5.0, p = 0.040). A small cup anteversion angle and a decreased femoral offset are suggested to be associated with posterior dislocation after total hip arthroplasty in patients with osteonecrosis of the femoral head. [ABSTRACT FROM AUTHOR]

Objective: Direct anterior approach total hip replacement (DAA-THR) is gaining increased interest due to its tissue-sparing nature and rapid recovery. Obesity has been shown to be a significant parameter influencing cup positioning in DAA-THR. It was the intention of this retrospective study to examine how obesity would influence the restoration of native hip biomechanical parameters during DAA-THR. Materials and Methods: A total of 74 patients from a high-volume university orthopedic center after unilateral DAA-THA were included. Patients were retrospectively allocated to a study group (BMI > 30 kg/m2) and a control group (BMI < 30 kg/m2). Furthermore, propensity-score matching for baseline parameters was performed, leaving 30 patients in each group. Biomechanical parameters of the hip (i.e., femoral offset (FO), abductor lever arm (ABL), acetabular offset (AO), center of rotation (COR), stem alignment (SA), body weight lever arm (BWL), cup inclination (CI), and leg length discrepancy (LLD) were evaluated on standardized plain radiographs, and parameters were compared to the native contralateral hip. Results: Mean BMI in the study group was 35.07 ± 5.13 kg/m2 and 25.43 ± 2.64 kg/m2 in the control group. There was a significant decrease of the ABL only in the study cohort (p = 0.01). CI and SA did not differ between both cohorts. FO was slightly increased compared to the native hip in both groups. There was a marginally higher but non-significant proportion of improper FO restoration in the study group (19 vs. 16 patients, p = 0.60). Conclusions: Obesity, as quantified by BMI, only has a limited impact on the adequate reconstruction of native biomechanical parameters of the hip during DAA-THR. ABL was the only parameter to be significantly decreased in the overweight patients after DAA-THR. Therefore, special care should be taken on proper acetabular reaming and consequent seating of the cup in the obese patient to avoid excessive lateral positioning. [ABSTRACT FROM AUTHOR]

Abstract Background Femoral offset (FO) restoration plays an important role in improving the prognosis and quality of life of patients undergoing hip replacement. However, it is not given enough attention in revisions among patients with periprosthetic femoral fractures (PPFFs); instead, more attention is given to reduction, fixation of fractures and stabilizing prostheses. The primary objective of this study was to evaluate the effect of FO restoration on the function of the hip joint in revisions of patients with PPFF of Vancouver B2. Moreover, we studied whether there is a difference in FO restoration between modular and nonmodular stems. Methods A retrospective review of 20 patients with PPFF of Vancouver B2 revised with a tapered fluted modular titanium stem and 22 patients with PPFF of Vancouver B2 revised with a tapered fluted nonmodular titanium stem from 2016 to 2021 was conducted. Based on the difference between the FO of the affected side and that of the healthy side, 26 patients were allocated into Group A (difference ≤ 4 mm), and 16 patients were allocated into Group B (difference > 4 mm). The postoperative Harris Hip Score (HHS), range of motion of the hip joint, length of both lower limbs and dislocation were compared between Group A and Group B. The proportions of patients with FO restoration (difference ≤ 4 mm) and stem subsidence were compared between the modular and nonmodular groups. Results The mean follow-up time was 34.3 ± 17.3 months, and all cases achieved fracture healing at the last visit. Patients in Group A had a higher HHS, larger range of abduction, fewer dislocations and less limb length discrepancy (LLD). Patients in the modular group had a higher proportion of FO restoration and less subsidence. Conclusion FO restoration improves postoperative hip joint function and reduces dislocation and LLD in revisions of patients with PPFF of Vancouver B2. Compared with nonmodular prostheses, modular prostheses tend to be easier for FO restoration under complex circumstances.

Purpose: Failure to restore the femoral offset of the native hip is a potential cause of dysfunctional hip arthroplasty. The aim of this study was to report our experience of using a modular head–neck adapter in revision THA, specifically analyzing its usefulness as a tool to correct a slightly diminished femoral offset. Materials and methods: This was a retrospective single-center study including all hip revisions performed at our institution from January 2017 to March 2022 where the BioBallTM head–neck metal adapter was used. The preoperative and one year follow-up modified Merle d'Aubigné hip score was used to evaluate functional outcomes. Results: Of a total of 34 cases included for revision, the head–neck adapter system was used specifically in six patients (17.6%) to increase femoral offset, retaining both the acetabular and femoral components. In this subgroup of patients, mean offset decrease after primary THA was 6.6 mm (4.0–9.1), equivalent to a mean 16.3% femoral offset reduction. The median modified Merle d'Aubigné score went from 13.3 preoperatively to 16.2 at one year follow-up. Conclusion: The use of a head–neck adapter is a safe and reliable procedure that may allow the surgeon to easily correct a slightly diminished femoral offset in a dysfunctional THA without the need to revise well-fixed prosthetic components. [ABSTRACT FROM AUTHOR]

Background: Femoral offset (FO) restoration plays an important role in improving the prognosis and quality of life of patients undergoing hip replacement. However, it is not given enough attention in revisions among patients with periprosthetic femoral fractures (PPFFs); instead, more attention is given to reduction, fixation of fractures and stabilizing prostheses. The primary objective of this study was to evaluate the effect of FO restoration on the function of the hip joint in revisions of patients with PPFF of Vancouver B2. Moreover, we studied whether there is a difference in FO restoration between modular and nonmodular stems. Methods: A retrospective review of 20 patients with PPFF of Vancouver B2 revised with a tapered fluted modular titanium stem and 22 patients with PPFF of Vancouver B2 revised with a tapered fluted nonmodular titanium stem from 2016 to 2021 was conducted. Based on the difference between the FO of the affected side and that of the healthy side, 26 patients were allocated into Group A (difference ≤ 4 mm), and 16 patients were allocated into Group B (difference > 4 mm). The postoperative Harris Hip Score (HHS), range of motion of the hip joint, length of both lower limbs and dislocation were compared between Group A and Group B. The proportions of patients with FO restoration (difference ≤ 4 mm) and stem subsidence were compared between the modular and nonmodular groups. Results: The mean follow-up time was 34.3 ± 17.3 months, and all cases achieved fracture healing at the last visit. Patients in Group A had a higher HHS, larger range of abduction, fewer dislocations and less limb length discrepancy (LLD). Patients in the modular group had a higher proportion of FO restoration and less subsidence. Conclusion: FO restoration improves postoperative hip joint function and reduces dislocation and LLD in revisions of patients with PPFF of Vancouver B2. Compared with nonmodular prostheses, modular prostheses tend to be easier for FO restoration under complex circumstances. [ABSTRACT FROM AUTHOR]

Introduction Femoral neck fracture is one of the most common orthopaedic traumas affecting the elderly population. The standard treatment method is hip hemiarthroplasty and total hip arthroplasty. In hip hemiprostheses surgeons mainly have to reconstruct the femoral offset and limbs’ length to obtain the correct gait biomechanics and a satisfactory surgical outcome. The aim of this study is to examine the radiological results of patients after hip hemiarthroplasty for femoral neck fracture and to evaluate the reconstruction of the femoral offset using standard neck angle stems. Material and methods A consecutive series of 97 patients diagnosed with femoral neck fracture treated with a hip hemiprosthesis between 2017 and 2021 was identified and met the inclusion criteria. On preoperative images, the neck-shaft angle and the femoral offset on the healthy limb were measured. The femoral offset of the operated limb was measured on the postoperative X-rays. Results There was a significant positive moderate correlation between neck-shaft angle and femoral offset change (r = 0.568, p < 0.0001). There was a statistically significant difference between femoral offset change and neck-shaft angle (24:52 vs. 14:7, p = 0.005). This means that in patients with coxa vara the change in femoral offset was more often < –5 mm. Less than half of operated patients had the femoral offset restored within a safe range (between –5 and 5 mm). Conclusions Our study proved that it is sometimes hard to achieve femoral offset within a safe range while performing hip hemiarthroplasty in patients with coxa vara. The topic of using high offset stems in partial hip arthroplasty has not been thoroughly researched worldwide. However, taking into account the results of our study, during a hip hemiarthroplasty the usage of high offset stems for varus hips should be considered in order to improve the clinical outcome and improve patients’ quality of life and functioning.

Introduction: Differences in leg and hip morphology exist between sexes and developmental hip dysplasia is known to alter proximal femoral morphology. The purpose of this study was to determine whether existing differences in leg alignment due to sex or developmental hip dysplasia have an effect on changes in leg alignment after total hip arthroplasty. Materials and methods: 30 hip osteoarthritis patients underwent biplanar full-length radiography in the standing position preoperatively and 3 months after total hip arthroplasty. Differences in leg alignment between men and women and between patients with primary hip osteoarthritis and patients with developmental dysplasia before and after surgery were tested using a general linear model for repeated measures. Results: Implantation of a hip prosthesis had no differential effect on ipsilateral leg alignment in patients with hip osteoarthritis due to dysplasia and in patients with primary hip osteoarthritis. However, patients with hip osteoarthritis due to dysplasia had a 2.1° higher valgus both before and after surgery. After total hip arthroplasty, women had a significantly greater increase in varus angle (1.6° vs. 0°) and femoral offset (10.5 vs. 4.6 mm) compared with men. Because the change in acetabular offset was smaller (2.2 vs. 6.2 mm), the global femoral offset was only increased in women. Femoral torsion was constant for men (15.0° and 16.5°), whereas femoral torsion was significantly reduced in women (19.9° and 13.2°). Conclusions: Hip arthroplasty has a greater effect on leg axis in women than in men. The axial leg alignment of women could change from a natural valgus to a varus alignment. Therefore, surgeons should consider the effects of total hip arthroplasty on leg alignment in patients with hip osteoarthritis. Whether these changes in leg alignment are also clinically relevant and lead to premature medial or lateral knee osteoarthritis should be investigated in future work. Trial registration: This study was registered with DRKS (German Clinical Trials Register) under the number DRKS00015053. Registered 1st of August 2018. [ABSTRACT FROM AUTHOR]

Although the hip joint morphology varies by race, few studies have investigated the associations between two-dimensional (2D) and three-dimensional (3D) morphologies. This study aimed to use computed tomography simulation data and radiographic (2D) data to clarify the 3D length of offset, 3D changes in the hip center of rotation, and femoral offset as well as investigate the anatomical parameters associated with the 3D length and changes. Sixty-six Japanese patients with a normal femoral head shape on the contralateral side were selected. In addition to radiographic femoral, acetabular, and global offsets, 3D femoral and cup offsets were investigated using commercial software. Our findings revealed that the mean 3D femoral and cup offsets were 40.0 mm and 45.5 mm, respectively; both were distributed around the mean values. The difference between the 3D femoral and cup offsets (i.e., 5 mm) was associated with the 2D acetabular offset. The 3D femoral offset was associated with the body length. In conclusion, these findings can be applied to the design of better ethnic-specific stem designs and can help physicians achieve more accurate preoperative diagnoses. [ABSTRACT FROM AUTHOR]

Background: Leg length and hip offset are important principles in total hip arthroplasty (THA). Patients may endorse leg length differences (LLD) postoperatively that may be anatomical or functional. The objective of this study was to determine the normal radiographic variation in leg length and hip offset in a preosteoarthritic population without a THA. Methods: A retrospective study was completed using data from the Osteoarthritis Initiative, a prospective longitudinal study. Patients at risk of developing or with early osteoarthritis without inflammatory arthritis or prior THA were included. Measurements were made from full limb length anterior-posterior (AP) radiographs. Multiple linear regression models were employed to predict side-to-side differences in LLD, Δ femoral offset (FO), Δ abductor muscle length (AML), Δ abductor lever arm, and Δ AP pelvic offset. Results: The mean radiographic LLD was 4.6 mm, with 12 mm within 1 standard deviation. No significant differences were detected between LLD and sex, age, body mass index, or height. The median radiographic differences in FO, AML, abductor lever arm, and AP pelvic offset were 3.2 mm, 4.8 mm, 3.6 mm, and 3.3 mm, respectively. Height was predictive of Δ FO, while both height and age were predictive of Δ AML. Conclusions: Radiographic leg length variations in a population without symptomatic or radiographic osteoarthritis exist. FO and AML are dependent on patient characteristics. Preoperative radiographic LLD is not predicted by age, gender, body mass index, or height. It should be stressed that anatomic reconstruction is one of the many goals of arthroplasty and can stand in conflict with the priority and primary goals of stability and fixation, which should be prioritized.

Purpose: Short stems are increasingly used in total hip arthroplasty (THA) because of advantages in bone and soft tissue preservation and reconstruction of hip geometry. Digital templating is essential in determining the correct offset option and stem size in THA. However, the preoperative template sizes might be intraoperatively overruled. Patients and methods: We evaluated the effect of intraoperative overruling of the preoperatively templated offset option of a short curved stem on hip offset, leg length, implant positioning, and femoral canal fill index. The overruling was performed in case of intraoperative instability, telescoping, or both. A series of 1052 consecutive THAs with a cementless short curved stem and press-fit cup was retrospectively screened. One hundred patients with unilateral THA and a contralateral native and morphologically healthy hip as a reference met the inclusion criteria. Measurements were carried out on preoperative and 3 months anterior–posterior postoperative radiographs. Patients were divided according to the overruling by offset option or stem size. Results: Hip offset was increased in all groups, but only with significant increase if an offset option + 1 was used intraoperatively (p = 0.025). LLD was restored without significance in all groups (p = 0.323; p = 0.157). Conclusion: Intraoperative overruling of the preoperative digital template in cementless short stem total hip arthroplasty results in an increase of hip offset compared to a contralateral healthy hip. However, the increase is marginal and clearly under 5 mm compared to the contralateral healthy hip. [ABSTRACT FROM AUTHOR]

Abstract Objectives To establish and validate a novel method for aligning femoral rotation to accurately measure femoral offset for preoperative templating and component sizing, and to identify the physical location of two radiographic lines utilized in the described method. Materials and methods Cadaveric proximal femurs were skeletonized and mounted to a biaxial load frame. Two radiographic lines along the greater trochanter were identified fluoroscopically. The femurs were rotated, and images were taken when the lines appeared superimposed, then in 2-degree increments to 10° of internal and external rotation, and at 30°. Radiographic femoral offset was calculated at each angle, and the maximum and aligned offsets were compared. Bone was removed until the radiographic lines disappeared, then a metal wire was inserted in place of the bone to confirm that the lines reappeared. Results The physical locations of the radiographic landmarks were on the anterior and posterior aspects of the greater trochanter. The mean true femoral offset was 38.2 mm (range, 30.5–46.3 mm). The mean aligned femoral offset was 37.3 mm (range, 29.3–46.3 mm), a 2.4% underestimation. The mean angle between aligned and true offset was 3.6° of external rotation (range, 10°ER-8°IR). Intra-rater intraclass correlation coefficient was 0.991. Conclusion Alignment of the radiographic lines created by the anterior and posterior aspects of the greater trochanter is a reliable and accurate rotational positioning method for measuring true femoral offset when using plain films or fluoroscopy, which can aid surgeons with preoperative templating and intraoperative component placement for total hip arthroplasty.

Resumen: Introducción y objetivos: Los vástagos con doble modularidad fueron introducidos con la ventaja teórica de restaurar de forma más precisa la anatomía de la cadera a través del ajuste del offset femoral y la longitud de miembros. Los cuellos intercambiables permiten cambios intraoperatorios de angulación, anteversión y longitud. Nuestro objetivo es estudiar si se consigue una mejor corrección del offset femoral con la prótesis H MAX-M® (Limacorporate, San Daniele, Italia) frente a su homólogo monobloque. Material y métodos: Se realizó un estudio de cohortes prospectivo mediante muestreo consecutivo sobre pacientes intervenidos de artroplastia total de cadera con el diagnóstico de coxartrosis desde enero de 2011 hasta diciembre 2015. Esta cohorte posee 2 brazos, un brazo incluyó a los pacientes intervenidos mediante vástago con cuello modular y el otro a los pacientes intervenidos mediante vástago monobloque. Se realizó la medición radiográfica del offset de la cadera intervenida, la cadera contralateral y se calculó la diferencia entre ambos valores. Las medias de las mediciones obtenidas para cada brazo de la cohorte se compararon entre sí. Resultados: No se han observado diferencias estadísticamente significativas en la corrección del offset femoral entre el grupo modular y monobloque, determinado como la diferencia de offset entre la cadera operada y la cadera contralateral (p = 0,323). Tampoco se observaron diferencias en los valores de offset postoperatorio (p = 0,097). Cabe decir que tanto para la prótesis modular como para la prótesis monobloque el grupo mayoritario es aquel con offset restaurado (p = 0,001). Abstract: Introduction and objective: Dual modularity stems were introduced with the theoretical advantage of restoring hip anatomy more precisely through femoral offset and limb length adjustment. Interchangeable necks allow for intraoperative angulation, anteversion and length changes. Our objective is to study whether a better femoral offset correction is achieved with the H MAX-M® prosthesis (Limacorporate, San Daniele, Italy) compared to its monoblock counterpart. Material and methods: A prospective cohort study was conducted by means of consecutive sampling on adult patients undergoing total hip arthroplasty with the diagnosis of coxarthrosis between January 2011 and December 2015. This cohort has two arms, one arm included patients who underwent modular neck arthroplasty and the other included patients who underwent monoblock total hip arthroplasty. Radiographic offset measurement of the operated hip and the contralateral hip was performed, and the difference between both values was calculated. The mean of the measurements obtained for each arm of the cohort were compared with each other. Results: No statistically significant differences were observed in the difference in offset between the operated hip and the contralateral hip (P = .323). No statistically significant differences were observed in the correction of the femoral offset, determined as the difference between the operated hip and the contralateral hip (P = .323). Nor were differences observed in the postoperative offset values (P = .097). It should be noted that for both designs, the majority group is the one with restored offset (P = .001).

PurposeThis study aimed to introduce and investigate the safety and efficiency of the intraoperative central measurement method of the femoral head (IM-CMFH) to prevent leg length discrepancies (LLD) after hemiarthroplasty.MethodsOverall, 79 patients aged 75 to 85 years with femoral neck fractures who underwent hemiarthroplasty were divided into two groups: the Control group (n = 46) and the IM-CMFH group (n = 33). The two groups were compared for postoperative LLD and the proportions of patients with greater than 10 mm, 6–10 mm, and within 5 mm, postoperative femoral offset (FO) difference and the proportions of patients within 5 mm, incremental greater than 5 mm and reduction greater than 5 mm. Next, the vertical distance from the center of the femoral head to the tip of the greater trochanter on the anatomical axis of the femur (VD-CFH-TGTAAF), leg length, and FO on the operative and non-operative sides within the IM-CMFH group. Finally, operative time, hemoglobin loss, Harris scores 3 months after surgery, and postoperative complications were analyzed.ResultsCompared with the control group, the postoperative LLD and FO differences were significantly lower in the IM-CMFH group (P = 0.031; P = 0.012), and the proportion of patients with postoperative LLD greater than 10 mm decreased significantly (P = 0.041), while the proportion of patients with FO difference of within 5 mm increased (P = 0.009). In addition, there was no significant difference in the operative time, hemoglobin loss, and Harris score at 3 months postoperatively and postoperative complications between the two groups (P > 0.05). There was no significant difference in FO, leg-length, and VD-CFH-TGTAAF between the operative and non-operative sides within the IM-CMFH group (P > 0.05).ConclusionSatisfactory results can be achieved by using the IM-CMFH to prevent LLD following hemiarthroplasty, and there is no increase in operative time, hemoglobin loss, or postoperative complications. This technique is efficient for hemiarthroplasties and is both simple and convenient.

Purpose: Short stems are increasingly used in in total hip arthroplasty (THA) because of advantages in bone and soft tissue preservation and reconstruction of hip geometry. Short stems can be inserted in a more varus position compared to conventional straight stems. This poses the risk of final varus misplacement of the femoral component, which is not intended in all femoral short stems. Methods: We wanted to evaluate the effect of a high varus stem positioning in MIS THA on hip offset, leg length and femoral canal fill index. A series of 1052 consecutive THAs with a singular cementless femoral short stem and press-fit cup was retrospectively screened for inclusion. One hundred six patients with unilateral THA and a contralateral healthy hip met the inclusion criteria. Measurements were carried out on preoperative and 3 months anterior–posterior postoperative radiographs. Patients were divided into Group A (varus stem alignment ≤ 3°) and Group B (varus stem alignment > 3°). Results: Hip offset (HO) increased significantly in Group B by 4 mm (p = 0.013). No influence on leg length difference was detected in both groups. Preoperative CCD angle was significantly lower in Group B (p < 0.001). Canal Fill Indices (CFI) were significantly lower in Group B (CFI I: p < 0.001; CFI II p = 0.003; CF III p = 0.002). Conclusion: High varus stem alignment > 3° leads to a statistically significant but minor increase in HO and poses the risk of stem undersizing. A preoperatively low genuine CCD angle pose a risk for varus stem positioning. [ABSTRACT FROM AUTHOR]

Background: The concept of restoring the femoral offset is well established during hip replacement surgery, but is less well known when treating Garden I or II femoral neck fractures by internal fixation. And yet, the therapeutic aim for these fractures is to restore this native parameter as best possible. The aim of this study was to identify the risk factors for reduction of femoral offset after union of a Garden I or II femoral neck fracture treated by internal fixation., Hypothesis: After internal fixation of a femoral neck fracture, certain factors may contribute to reducing the femoral offset, which itself has been identified as being responsible for altering the patients' quality of life and functional outcomes., Materials and Methods: This multicenter study included 193 patients who had a Garden I or II femoral neck fracture treated by cannulated screws or a sliding compression screw-plate. The difference between the femoral offset in the operated hip and that of the contralateral hip was measured in weightbearing patients after the fracture had healed. This difference was the primary outcome measure. Univariate and multivariate analyses were done to look for risk factors contributing to femoral neck shortening., Results: Based on the univariate analysis, being more than 85 years of age, having a Garden I fracture, and cannulated screw fixation were associated with a significantly greater reduction in the femoral offset. In the multivariate analysis, only Garden I fractures were associated with a greater reduction in femoral offset., Discussion: Garden I fractures were associated with a greater reduction in the offset, although there was no evidence that this change was related to early weightbearing. By identifying this risk factor, surgeons can optimize the indications given that the treatment of these fractures is still widely debated and there is still no consensus as to the best method., Level of Evidence: IV., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Introduction: Femoral neck fracture is one of the most common orthopaedic traumas affecting the elderly population. The standard treatment method is hip hemiarthroplasty and total hip arthroplasty. In hip hemiprostheses surgeons mainly have to reconstruct the femoral offset and limbs' length to obtain the correct gait biomechanics and a satisfactory surgical outcome. The aim of this study is to examine the radiological results of patients after hip hemiarthroplasty for femoral neck fracture and to evaluate the reconstruction of the femoral offset using standard neck angle stems. Material and methods: A consecutive series of 97 patients diagnosed with femoral neck fracture treated with a hip hemiprosthesis between 2017 and 2021 was identified and met the inclusion criteria. On preoperative images, the neck-shaft angle and the femoral offset on the healthy limb were measured. The femoral offset of the operated limb was measured on the postoperative X-rays. Results: There was a significant positive moderate correlation between neck-shaft angle and femoral offset change (r = 0.568, p < 0.0001). There was a statistically significant difference between femoral offset change and neck-shaft angle (24:52 vs. 14:7, p = 0.005). This means that in patients with coxa vara the change in femoral offset was more often < -5 mm. Less than half of operated patients had the femoral offset restored within a safe range (between -5 and 5 mm). Conclusions: Our study proved that it is sometimes hard to achieve femoral offset within a safe range while performing hip hemiarthroplasty in patients with coxa vara. The topic of using high offset stems in partial hip arthroplasty has not been thoroughly researched worldwide. However, taking into account the results of our study, during a hip hemiarthroplasty the usage of high offset stems for varus hips should be considered in order to improve the clinical outcome and improve patients' quality of life and functioning. [ABSTRACT FROM AUTHOR]

The impact of femoral anteversion changes on femoral rotation and anterior offset following total hip arthroplasty (THA) has not been well studied. This study therefore investigated the relationship among femoral anteversion, anterior offset, and femoral rotation before and after THA. There were 995 patients who had staged primary bilateral THAs who received a preoperative supine computerized axial tomography (CT) scan, following a standardized protocol, for surgical planning prior to each THA. The following measurements were performed for the first operative hip preoperatively and postoperatively on the first and second CT scans, respectively: femoral anatomic anteversion, defined as the angle between the native femoral neck or stem neck axis and the posterior condylar axis; femoral rotation, defined as the angle of the posterior condylar axis relative to the coronal plane of the CT; and femoral anterior offset, defined as the shortest distance between the femoral head center and a femoral plane containing the epicondyles and the piriformis fossa. The mean time between imagings was 11 months (range, 2 to 44). Associations are described using linear regression (β = slope) and Pearson correlation (r) coefficients. A t distribution was used for testing correlation. Femoral anteversion correlated with femoral anterior offset preoperatively (β = 0.565, r = 0.914, P < 0.001) and postoperatively (β = 0.671, r = 0.958, P < 0.001), and with femoral rotation preoperatively (β = 0.623, r = 0.575, P < 0.001) and postoperatively (β = 0.459, r = 0.517, P < 0.001). Increasing anteversion from preoperatively to postoperatively increased anterior offset (β = 0.621, r = 0.908, P < 0.001) and femoral internal rotation (IR) (β = 0.241, r = 0.273, P < 0.001). Patients who had >20° increase in anteversion (mean increase 26°, range 20 to 40.5°, n = 71) had a mean increase in femoral IR of 9.6 ± 9.8°. Increasing femoral anteversion increases anterior offset and IR of the femur, with approximately a 1° increase in IR for every 4° increase in anteversion on average. Surgeons should appreciate the implications of changing anteversion during THA planning. [ABSTRACT FROM AUTHOR]

Abstract Background The effect of change in hip anatomy on change in gait pattern is not well described in current literature. Therefore, our primary aim was to describe and quantify changes in hip geometry and gait pattern 1 year after total hip arthroplasty (THA) in individuals with hip osteoarthritis. Our secondary aim was to explore the effect of postoperative change in femoral neck anteversion (FNA) and femoral offset and acetabular offset (FO/AO) quota on postoperative change in hip rotation and hip adduction moment during gait, respectively, 1 year after THA”. Methods Sixty-five individuals with primary hip osteoarthritis, scheduled for THA, were analyzed in this prospective intervention study. Participants were evaluated pre- and 1 year postoperatively with computed tomography-scans, three-dimensional gait analysis, and patient-reported outcome measures. Multiple linear regressions were performed to evaluate the association between change in joint anatomy and change in gait pattern after THA. Results One year postoperatively, global offset was symmetrical between sides as a result of decreased acetabular offset and increased femoral offset on the operated side. Quality of overall gait pattern improved, and participants walked faster and with less trunk lean over the affected side. FNA and hip rotations during walking changed equally in external and internal directions after THA and change in hip rotation during walking was associated with change in FNA in the same direction. An increase in external hip adduction moments was, on the other hand, not associated with change in FO/AO quota but with a more upright walking position and increased walking speed. Conclusions The findings of this study suggest that geometrical restoration during THA impacts postoperative gait pattern and, in addition to known factors such as FO, height of hip rotation center, and leg length discrepancy, the FNA must also be taken into consideration. Trial registration Trial registration: Clinicaltrial.gov , NCT01512550 , Registered 19 January 2012 - Retrospectively registered.

Accurate hip reconstruction is associated with improved biomechanical behavior following total hip arthroplasty (THA). However, whether this is associated with improved patient-reported outcomes (PROs) is unknown. This study aimed to: 1) describe the ability to reconstruct coronal geometry during THA without advanced technology; 2) assess whether restoration of global offset (GO) and leg length (LL) is associated with improved PROs; and 3) investigate whether increased femoral offset (FO) to compensate for reduced acetabular offset (AO) influences PROs. This was a prospective, multicenter, consecutive cohort study of 500 patients treated with primary THA without robotics or navigation. The Oxford Hip score (OHS) was obtained preoperatively and at 1-year follow-up. Supine anteroposterior pelvic radiographs were analyzed to determine AO, FO, GO, and LL relative to the native contralateral side. Contour plots for ΔOHS based on ΔLL and ΔGO were created, and ΔOHS was calculated within and outside various ranges (±2.5, ±5, or ±10 mm). In the operated hip, mean FO increased by 3 ± 6 mm (range, −16 to 27), while AO decreased by 2 ± 4 mm (range, −17 to 10). The contour graph for ±2.5 mm zones showed the best outcomes (ΔOHS >25) with GO and LL centered on 0 ± 2.5 mm (P <.01). However, only 10% achieved such reconstruction. When GO and LL differences were within ±10 mm, ΔOHS was superior when both AO and FO were within ±5 mm (mean: 24 ± 10; range, −5 to 40) compared with when FO was above 5 mm to compensate for a reduction in AO (mean: 22 ± 11; range, −10 to 46; P =.040). The PROs were associated with biomechanical reconstruction, and the best clinical improvement can be expected when GO and LL differences are both within 2.5 mm. Maintenance of AO is important, as compensation by increasing FO is associated with inferior OHS. [ABSTRACT FROM AUTHOR]

Although the hip joint morphology varies by race, few studies have investigated the associations between two-dimensional (2D) and three-dimensional (3D) morphologies. This study aimed to use computed tomography simulation data and radiographic (2D) data to clarify the 3D length of offset, 3D changes in the hip center of rotation, and femoral offset as well as investigate the anatomical parameters associated with the 3D length and changes. Sixty-six Japanese patients with a normal femoral head shape on the contralateral side were selected. In addition to radiographic femoral, acetabular, and global offsets, 3D femoral and cup offsets were investigated using commercial software. Our findings revealed that the mean 3D femoral and cup offsets were 40.0 mm and 45.5 mm, respectively; both were distributed around the mean values. The difference between the 3D femoral and cup offsets (i.e., 5 mm) was associated with the 2D acetabular offset. The 3D femoral offset was associated with the body length. In conclusion, these findings can be applied to the design of better ethnic-specific stem designs and can help physicians achieve more accurate preoperative diagnoses.

Objectives: To establish and validate a novel method for aligning femoral rotation to accurately measure femoral offset for preoperative templating and component sizing, and to identify the physical location of two radiographic lines utilized in the described method. Materials and methods: Cadaveric proximal femurs were skeletonized and mounted to a biaxial load frame. Two radiographic lines along the greater trochanter were identified fluoroscopically. The femurs were rotated, and images were taken when the lines appeared superimposed, then in 2-degree increments to 10° of internal and external rotation, and at 30°. Radiographic femoral offset was calculated at each angle, and the maximum and aligned offsets were compared. Bone was removed until the radiographic lines disappeared, then a metal wire was inserted in place of the bone to confirm that the lines reappeared. Results: The physical locations of the radiographic landmarks were on the anterior and posterior aspects of the greater trochanter. The mean true femoral offset was 38.2 mm (range, 30.5–46.3 mm). The mean aligned femoral offset was 37.3 mm (range, 29.3–46.3 mm), a 2.4% underestimation. The mean angle between aligned and true offset was 3.6° of external rotation (range, 10°ER-8°IR). Intra-rater intraclass correlation coefficient was 0.991. Conclusion: Alignment of the radiographic lines created by the anterior and posterior aspects of the greater trochanter is a reliable and accurate rotational positioning method for measuring true femoral offset when using plain films or fluoroscopy, which can aid surgeons with preoperative templating and intraoperative component placement for total hip arthroplasty. [ABSTRACT FROM AUTHOR]

Abstract Background Inaccurate projection on standard pelvic radiographs leads to the underestimation of femoral offset—a critical determinant of postoperative hip function—during total hip arthroplasty (THA) templating. We noted that the posteromedial facet of the greater trochanter and piriformis fossa form a double contour on radiographs, which may be valuable in determining the risk of underestimating femoral offset. We evaluate whether projection errors can be predicted based on the double contour width. Methods Plain anteroposterior (AP) pelvic radiographs and magnetic resonance images (MRIs) of 64 adult hips were evaluated retrospectively. Apparent femoral offset, apparent femoral head diameter and double contour widths were evaluated from the radiographs. X-ray projection errors were estimated by comparison to the true neck length measured on MRIs after calibration to the femoral heads. Multivariate analysis with backward elimination was used to detect associations between the double contour width and radiographic projection errors. Femoral offset underestimation below 10% was considered acceptable for templating. Results The narrowest width of the double line between the femoral neck and piriformis fossa is significantly associated with projection error. When double line widths exceed 5 mm, the risk of projection error greater than 10% is significantly increased compared to narrower double lines, and the acceptability rate for templating drops below 80% (p = 0.02). Conclusion The double contour width is a potential landmark for excluding pelvic AP radiographs unsuitable for THA templating due to inaccurate femoral rotation.

Background: Cup medialisation down to the true acetabular floor in total hip arthroplasty with a compensatory femoral offset increase seems to be mechanically advantageous for the abductor muscles due to the relocation of the lever arms (body weight lever arm decreased, abductor lever arm increased). However, limited information is currently available about the effects of this reconstruction type at the head cup interface, compared to an anatomical reconstruction that maintains the natural lever arms. Through a whole-body simulation analysis, we compared medialised versus anatomical reconstruction in THA to analyse the effects on: (1) contact force magnitude at the head cup interface; (2) contact force path in the cup; and (3) abductor activity. Methods: Musculoskeletal simulations were performed to calculate the above-mentioned parameters using inverse dynamics analysis. The differences between the virtually implanted THAs were calculated to compare the medialised versus anatomical reconstruction. Results: Cup medialisation with compensatory femoral offset increase led to: (1) a reduction in contact force magnitude at the head cup interface up to 6.6%; (2) a similar contact force path in the cup in terms of sliding distance and aspect ratio; and (3) a reduction in abductor activity up to 17.2% (gluteus medius). Conclusions: In our opinion, these potential biomechanical gains do not generally justify a fully medialised reconstruction, especially in younger patients that are more likely to undergo revision surgery in their lifetime. Cup medialisation should be performed until sufficient press fit and bony coverage of a properly sized and oriented cup can be achieved. [ABSTRACT FROM AUTHOR]

Abstract Background In obese patients, total hip arthroplasty (THA) can be technically demanding with increased perioperative risks. The aim of this prospective cohort study is to evaluate the effect of body mass index (BMI) on radiological restoration of femoral offset (FO) and leg length as well as acetabular cup positioning. Methods In this prospective study, patients with unilateral primary osteoarthritis (OA) treated with THA between September 2010 and December 2013 were considered for inclusion. The perioperative plain radiographs were standardised and used to measure the preoperative degree of hip osteoarthritis, postoperative FO, leg length discrepancy (LLD), acetabular component inclination and anteversion. Results We included 213 patients (74.5% of those considered for inclusion) with a mean BMI of 27.7 (SD 4.5) in the final analysis. The postoperative FO was improper in 55% and the LLD in 15%, while the cup inclination and anteversion were improper in 13 and 23% of patients respectively. A multivariable logistic regression model identified BMI as the only factor that affected LLD. Increased BMI increased the risk of LLD (OR 1.14, 95% CI 1.04 to 1.25). No other factors included in the model affected any of the primary or secondary outcomes. Conclusion Increased BMI showed a negative effect on restoration of post-THA leg length but not on restoration of FO or positioning of the acetabular cup. Age, gender, OA duration or radiological severity and surgeon’s experience showed no relation to post-THA restoration of FO, leg length or cup positioning.

Introduction: Inaccurate stem implantation can cause unsatisfactory offset reconstruction and may result in insufficient gluteal muscle function or aseptic loosening. In this study, stem alignment of a collarless straight tapered HA-coated stem was retrospectively analyzed during the learning phase of the direct anterior approach (DAA) for primary total hip arthroplasty (THA).Material and Methods: From Jan 2013 to Jun 2015, a total of 93 cementless THA were implanted in patients with unilateral coxarthrosis via the DAA in a two surgeon setting using the Corail® or Trendhip® stem (DePuy Synthes or Aesculap). Varus(+)/Valgus(-) stem alignment was analyzed in postoperative anteroposterior pelvic radiographs. Effects on femoral offset reconstruction and correlation to patient's individual clinical and radiological parameters were evaluated.Results: 55 stems were implanted in varus (59%), 32 in neutral (34%) and 6 in valgus alignment (7%). Mean stem alignment in varus position was + 2.2° (SD ± 1.4°). Varus alignment was associated with male gender and preoperative coxa vara deformity: low CCD, high femoral offset and long thigh neck (p ≤ 0.001). Alignment was not correlated to femoral offset restoration, BMI or leg length difference. Mean cup inclination was 44° (SD ± 4.7°) and 90% matched the coronal Lewinnek safe zone.Conclusion: In the learning curve, the DAA can be associated with a high incidence of varus stem alignment when using a straight tapered stem, especially in men with coxa vara deformity: low CCD, high femoral offset and long thigh neck. An insufficient capsule release makes femur exposure more difficult and might be an additional factor for this finding. We recommend intraoperative X-ray in the learning phase of the DAA to verify correct implant positioning and to adjust offset options. [ABSTRACT FROM AUTHOR]

Increased femoral offset following total hip arthroplasty allows for greater stability of the hip joint. However, the increase in femoral offset can cause an impingement of local structures resulting in persistent lateral hip pain. There is conflicting evidence whether changes in femoral offset increases the rates of lateral hip pain following total hip arthroplasty. This was a retrospective case control study that grouped patients based on the presence of persistent lateral hip pain following total hip arthroplasty. Patients were then stratified according to their change in femoral offset (<-5 mm, -5 mm < x < 5 mm, and 5 mm<). A chi squared analysis was then performed to see if there was a statistical difference in the rates of lateral hip pain amongst these groups. A change in femoral offset of the implanted hip relative to the native hip was not associated with increased rates of lateral hip pain following total hip arthroplasty (p = 0.35). A change in femoral offset of the implanted hip relative to the contralateral hip was not associated with increased rates of lateral hip pain following total hip arthroplasty (p = 0.40). This study found that there was no association between increased femoral offset and rates of postoperative lateral hip pain following total hip arthroplasty. Future investigations should look at a larger sample size with multiple institutions to further assess the impact on femoral offset changes on rates of persistent lateral hip pain. [ABSTRACT FROM AUTHOR]

Background: The effect of change in hip anatomy on change in gait pattern is not well described in current literature. Therefore, our primary aim was to describe and quantify changes in hip geometry and gait pattern 1 year after total hip arthroplasty (THA) in individuals with hip osteoarthritis. Our secondary aim was to explore the effect of postoperative change in femoral neck anteversion (FNA) and femoral offset and acetabular offset (FO/AO) quota on postoperative change in hip rotation and hip adduction moment during gait, respectively, 1 year after THA".Methods: Sixty-five individuals with primary hip osteoarthritis, scheduled for THA, were analyzed in this prospective intervention study. Participants were evaluated pre- and 1 year postoperatively with computed tomography-scans, three-dimensional gait analysis, and patient-reported outcome measures. Multiple linear regressions were performed to evaluate the association between change in joint anatomy and change in gait pattern after THA.Results: One year postoperatively, global offset was symmetrical between sides as a result of decreased acetabular offset and increased femoral offset on the operated side. Quality of overall gait pattern improved, and participants walked faster and with less trunk lean over the affected side. FNA and hip rotations during walking changed equally in external and internal directions after THA and change in hip rotation during walking was associated with change in FNA in the same direction. An increase in external hip adduction moments was, on the other hand, not associated with change in FO/AO quota but with a more upright walking position and increased walking speed.Conclusions: The findings of this study suggest that geometrical restoration during THA impacts postoperative gait pattern and, in addition to known factors such as FO, height of hip rotation center, and leg length discrepancy, the FNA must also be taken into consideration.Trial Registration: Trial registration: Clinicaltrial.gov , NCT01512550 , Registered 19 January 2012 - Retrospectively registered. [ABSTRACT FROM AUTHOR]

Purpose: The goal of total hip endoprosthesis is to achieve painless and functional hip for long term. Accurate reconstruction of hip anatomy largely depends on the implant design. In order to select an implant in correspondence with the native hip, the proximal femoral morphology has been in focus of many studies in the past years. The purpose of this study is to analyze proximal femoral geometry in the Croatian population by radiographic evaluation. Methods: We conducted a retrospective study analyzing conventional radiographies of the hip, obtained within the last four years from the database of Clinic for Orthopaedic Surgery Lovran. The number of studied patients was 300,168 women and 132 men. The proximal femoral geometric parameters assessed were as follows: femoral head diameter, femoral neck length, neck-shaft angle, angle of femoral neck anteversion, and lateral femoral offset. The results obtained were compared between genders and with results of other studies. Results: Proximal femoral anatomy differed in femoral head diameter and lateral femoral offset between males and females in our group of patients, while femoral neck length, femoral neck shaft angle, and femoral neck anteversion have shown similar values in both genders. Our study also showed specificity of the Croatian population in almost all parameters of proximal femoral anatomy, in comparison with other ethnic groups. Conclusion: Our results support the observation on high diversity in the morphology of the proximal femur and the specificity of the proximal femoral anatomy of the Croatian population. [ABSTRACT FROM AUTHOR]

ObjectiveFemoral offset (FO) restoration is significantly correlated with functional recovery following total hip arthroplasty (THA). Accurately assessing the effects of FO changes on hip muscles following THA would help improve function and optimize functional outcomes. The present study aimed to (1) identify the impact of FO side difference on the hip muscle moment arms following unilateral THA during gait and (2) propose the optimal FO for a physiological hip muscle function.MethodsIn vivo hip kinematics from eighteen unilateral THA patients during gait were measured with a dual-fluoroscopic imaging system. The moment arms of thirteen hip muscles were calculated using CT-based 3D musculoskeletal models with the hip muscles’ lines of actions. The correlation coefficient (R) between FO and hip muscle moment arm changes compared with the non-implanted hip was calculated. We considered that the FO reconstruction was satisfactory when the abductor moment arms increased, while the extensor, adductor, and flexor moment arms decreased less than 5%.ResultsA decreased FO following THA was significantly correlated with a decrease of the abductor and external rotator moment arms during the whole gait (R > 0.5) and a decrease of extensor moment arms during the stance phase (R > 0.4). An increased FO following THA was significantly associated with shorter flexor moment arms throughout the gait (R < −0.5) and shorter adductor moment arms in the stance phase (R < −0.4). An increase in FO of 2.3–2.9 mm resulted in increased abductor moment arms while maintaining the maximum decrease of the hip muscles at less than 5.0%.ConclusionAn increase of 2–3 mm in FO could improve the abductor and external rotator function following a THA. Accurate surgical planning with optimal FO reconstruction is essential to restoring normal hip muscle function in THA patients.

Background: Inaccurate projection on standard pelvic radiographs leads to the underestimation of femoral offset-a critical determinant of postoperative hip function-during total hip arthroplasty (THA) templating. We noted that the posteromedial facet of the greater trochanter and piriformis fossa form a double contour on radiographs, which may be valuable in determining the risk of underestimating femoral offset. We evaluate whether projection errors can be predicted based on the double contour width.Methods: Plain anteroposterior (AP) pelvic radiographs and magnetic resonance images (MRIs) of 64 adult hips were evaluated retrospectively. Apparent femoral offset, apparent femoral head diameter and double contour widths were evaluated from the radiographs. X-ray projection errors were estimated by comparison to the true neck length measured on MRIs after calibration to the femoral heads. Multivariate analysis with backward elimination was used to detect associations between the double contour width and radiographic projection errors. Femoral offset underestimation below 10% was considered acceptable for templating.Results: The narrowest width of the double line between the femoral neck and piriformis fossa is significantly associated with projection error. When double line widths exceed 5 mm, the risk of projection error greater than 10% is significantly increased compared to narrower double lines, and the acceptability rate for templating drops below 80% (p = 0.02).Conclusion: The double contour width is a potential landmark for excluding pelvic AP radiographs unsuitable for THA templating due to inaccurate femoral rotation. [ABSTRACT FROM AUTHOR]

Objective: CT scans combined with Mimics software were used to measure femoral offset (FO), rotation center height (RCH) and lower leg length discrepancy (LLD) following total hip arthroplasty (THA), and the relationship between FO, RCH and LLD after THA is discussed., Methods: Retrospective analysis was performed on 40 patients with unilateral THA who met standard cases from October 2020 to June 2022. There were 21 males and 19 females, 18 patients on the left side and 22 patients on the right side, aged range from 30 to 81 years old, with an average age of (58.90 ±14.13) years old, BMI ranged from 17.3 to 31.5 kg·m -2 with an average of (25.3±3.4) kg·m -2 . There were 30 cases of femoral head necrosis (Ficat type Ⅳ), 2 cases of hip osteoarthritis (Tönnis type Ⅲ), 2 cases of developmental hip dislocation combined with end-stage osteoarthritis (Crowe type Ⅲ), and 6 cases of femoral neck fracture (Garden type Ⅳ). Three-dimensional CT reconstruction of pelvis was taken preoperative and postoperative, and three-dimensional reconstruction model was established after processing by Mimics software. FO, RCH and LLD were measured on the model. The criteria for FO reconstruction were as follows:postoperative bilateral FO difference less than 5 mm;the standard for equal length of both lower limbs was as follows:postoperative LLD difference less than 5 mm., Results: Bilateral FO difference was positively correlated with LLD ( r =0.744, P <0.001). Chi-square test was performed between the FO reconstructed group and the non-reconstructed eccentricity group:The results showed that the isometric ratio of lower limbs in the FO reconstructed group was significantly higher than that in the FO reconstructed group ( χ 2 =6.320, P =0.012). The bilateral RCH difference was significantly negatively correlated with LLD( r =-0.877, P <0.001). There is a linear relationship between bilateral FO difference and bilateral RCH difference and postoperative LLD, and the linear regression equation is satisfied:postoperative LLD=0.038x-0.099y+0.257(x:postoperative bilateral FO difference, y:postoperative bilateral RCH difference; Unit:cm), F =77.993, R 2 =0.808, P =0.009., Conclusion: After THA, LLD increased with the increase of FO and decreased with the increase of RCH. The effect of lower limb isometric length can be obtained more easily by reconstruction of FO. There is a linear relationship between the bilateral FO difference and the bilateral RCH difference after THA and LLD, and the regression equation can provide a theoretical reference for judging LLD.

Background: Serum Cobalt (Co) and Chromium (Cr) forms part of the diagnostic process for metallosis following Total Hip Arthroplasty (THA). While knowledge exists on longer term metal ion levels, expected early post-operative rises in serum Co and Cr in Metal-on-Polyethylene (MoP) THAs are currently unknown. This study aims to describe early rises in serum Co and Cr at 6 months post-operatively. Methods: A prospective cohort study of 100 consecutive patients with an uncemented titanium stem from a single THA manufacturer was performed. Patients had either a metal (n=50) or ceramic (n=50) head articulating with a highly cross-linked polyethylene. Serum Co and Cr levels were measured 6 months post-operatively. Analysis compared mean values between groups and to determined baseline levels. Subgroup analysis investigated the effect of femoral head size and offset on metal ion levels. Results: A mean difference of 2.259 nmol/L (95% CI 0.449-4.069; p=0.015) was found when comparing 6-month serum Co in the metal head group compared to baseline. No significant differences were found in serum Cr (p=0.943). Mean serum Co levels were higher in the MoP group compared to the CoP (Ceramic-on-Polyethylene) comparator group (p=0.012). There were no differences in serum Cr (p=0.976). Variations in femoral head size and offset did not impact metal ion levels. Conclusion: At six months, a higher magnitude of serum Co exists in metal heads when compared to baseline (p=0.015) and to ceramic heads (p=0.012). Further study is required to determine whether serum concentrations of metal ions will continue to increase over time.

Introduction: Accurate reconstruction of biomechanical parameters following total hip arthroplasty (THA) is crucial for good joint function. We investigated how reconstruction parameters achieved by minimally invasive anterior (MIS) THA may influence function and patient-related outcomes. Methods: A consecutive series of 95 patients treated by MIS THA for primary osteoarthritis were retrospectively reviewed. Primary outcome measures were Harris Hip Score (HHS), hip disability and osteoarthritis outcome score (HOOS) and EQ-5D. Femoral offset (FO), abductor lever arm (ALA), centre of rotation (CoR), leg length discrepancy (LLD), cup version and stem alignment were measured pre- and post-operatively. Obtained reconstruction parameters compared to the contralateral hip were used as independent variables in a multivariate regression with each primary outcome measure as dependent variable. Results: Mean age at surgery was 69 years. HHS rated 94.7% of patients as good/excellent and mean EQ-5D was 0.82. Post-operative HOOS subscales showed no statistical difference compared to the Italian benchmark population. Stem alignment averaged 0.2° valgus, mean cup inclination was 37.8° and mean anteversion was 12.8°. When compared to the contralateral side, CoR was post-operatively elevated by 2.6 mm and medialized by 2.4 mm averagely. An average FO reduction of −0.5 mm was observed while FO ratio increased by 1.9% averagely. ALA decreased by −3.3 mm while LLD was 2.3 mm averagely. Multivariate regression analysis revealed a significant contribution of ALA to HHS only. Conclusions: Biomechanical parameters achieved by MIS THA are satisfactory with negligible impact on functional results and no impact on patient-related outcomes certifying the high quality achieved in THA. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the relationship between radiographic measurements of the hip and sonographic evidence of gluteal tendinopathy and bursitis in patients with lateral hip pain. Methods and materials: Patients with lateral hip pain referred for ultrasound of the hip in our institution over a 5-year period were identified. Findings of gluteal tendinopathy and subgluteal or trochanteric bursitis on ultrasound were recorded. Radiographs of the hip were also evaluated and femoral offset (FO), global offset (GO), abductor lever arm (ALA) and trochanteric impingement distance (TID) were recorded. The mean of each measurement was compared between patients with gluteal tendinopathy and subgluteal or trochanteric bursitis. Results: 273 patients were included in the study. 107 patients (39.2%) had a THA. In the asymptomatic hip, a range of normal measurements were obtained: FO 22.4–76.5 mm, GO 40.1–116.1 mm, ALA 45.0–98.4 mm and TID 13.8–63.1 mm. In the native hip and post THA, there was no statistically significant relationship between FO, GO, ALA and TID in patients with gluteal tendinopathy or trochanteric or subgluteal bursitis. Conclusions: Lateral hip pain is a common presenting complaint in patients with hip pain and is reported in a small proportion of patients post THA. No statistically significant relationship was found between radiographic measurements and ultrasound findings in our patient cohort. However, we describe the range of measurements obtained from the normal asymptomatic hip in this large cohort of patients, which may aid in the evaluation and management of patients with lateral hip pain. [ABSTRACT FROM AUTHOR]

The purpose of this systematic review was to analyze the effect of decreased, restored, or increased femoral offset on patient reported outcomes (PROs) following hip arthroplasty. Databases were searched according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. With regard to Harris Hip Score, two studies reported superior outcomes for the increased femoral offset group, one study reported superior outcomes for a restored offset group, and the final study reported favorable outcomes for the decreased offset group. Patients with restored offset following arthroplasty may demonstrate superior PROs. [ABSTRACT FROM AUTHOR]

Background: Restoration of a correct biomechanical situation after total hip arthroplasty is important. Purpose: To evaluate proximal femoral symmetry of acetabular and femoral offset and femoral neck anteversion pre- and postoperatively in hip arthroplasty by semi-automated 3D-CT and to validate the software measurements by inter- and intraobserver agreement calculations. Material and Methods: In low-dose CT on 71 patients before and after unilateral total hip arthroplasty, two observers used a digital 3D templating software to measure acetabular offset, true and functional femoral offset, and femoral neck anteversion. Observer agreements were calculated using intraclass correlation. Hip measurements were compared in each patient and between pre- and postoperative measurements. Results: Preoperatively, acetabular offset (2.4 mm), true (2.2 mm), and functional global offset (2.7 mm) were significantly larger on the osteoarthritic side without side-to-side differences for true and functional femoral offset or femoral neck anteversion. Postoperatively, acetabular offset was significantly smaller on the operated side (2.1 mm) with a concomitantly increased true (2.5 mm) and functional femoral offset (1.5 mm), resulting in symmetric true and functional global offsets. There were no differences in postoperative femoral neck anteversion. Inter- and intraobserver agreements were near-perfect, ranging between 0.92 and 0.98 with narrow confidence intervals (0.77–0.98 to 0.94–0.99). Conclusion: Acetabular and concomitantly global offset are generally increased in hip osteoarthritis. Postoperative acetabular offset was reduced, and femoral offset increased to maintain global offset. 3D measurements were reproducible with near-perfect observer agreements. 3D data sets should be used for pre- and postoperative measurements in hip arthroplasty. [ABSTRACT FROM AUTHOR]

Purpose: Approximately 10% of all patients that require a total knee arthroplasty present with valgus osteoarthritis (OA) of the knee. Valgus OA goes along with posterolateral bone loss and lateral soft tissue tightness. The role of malalignment on the development of OA is not fully understood. The current study investigates whether the femoral offset (FO), femoral mechanical-anatomical (FMA) angle, anatomical lateral distal femur angle (aLDFA), mechanical lateral distal femur angle (mLDFA), medial proximal femur angle (MPFA), medial proximal tibia angle (MPTA) or lateral distal tibia angle (LDTA) differ in patients with valgus OA of the knee.Methods: FO, FMA angle, aLDFA, mLDFA, MPFA, MPTA and LDTA were assessed and compared between 100 consecutive knees with minimal valgus OA (50 male, 50 female) and 100 consecutive knees with minimal varus OA (50 male, 50 female).Results: FO was significantly higher in males with valgus OA (p = 0.002) and females with varus OA (p = 0.01). The observed values for the FMA angle were significantly higher in males with valgus OA (p = 0.002) and females with varus OA (p = 0.041). The aLDFA and mLDFA were significantly smaller in all patients with valgus OA (p < 0.001). No differences between the varus and valgus groups were detected regarding MPFA (males: p = 0.052; females: p = 0.719). Tibial measurements showed significantly higher values for the MPTA (p < 0.001) in both valgus groups and no difference for LDTA (men: p = 0.139; women: p = 0.196).Conclusion: Bony alterations in the femoral anatomy seem to be more important than in the tibial anatomy. While in male patients with valgus OA, the main anatomic variation is the hypoplasia of the lateral femoral condyle, in females both decreased femoral offset of the hip as well as hypoplasia of the lateral condyle are present.Level Of Evidence: III. [ABSTRACT FROM AUTHOR]

Purpose: Biomechanical studies suggest that PF tracking is not reliably restored to physiological values in TKA despite surgical technique optimization. A clinical observation is that current TKA designs may not replicate anterior femoral offset. The aim was to examine the intraoperative resection thicknesses of the anterior femoral condyles during TKA and correlate these findings relative to modern prostheses.Methods: This was a retrospective analysis of 199 patients who underwent 233 TKAs using a single implant design with measured anterior femoral condylar resection thicknesses. The aim was to restore posterior condylar offset whilst minimizing overstuffing of the anterior compartment of the knee by choosing the smallest prosthesis to allow for the maximal anterior resection as close to the cortex without inducing notching. Prosthetic measurements from 7 commonly used TKAs were collected by analysis of 3D models of median sized explants.Results: An average of 7.9 mm (SD 2.5 mm, range 2-16.5 mm) and 11.5 mm (SD 2.5 mm, range 2-21 mm) was resected from the medial and lateral aspects of the anterior femur, respectively. The average anterior flange thickness for the prosthesis data set was 6.6 mm (SD 0.6 mm, range 6.1-7.9 mm) medially and 7.6 mm (SD 0.7 mm, range 6.8-9.0 mm) laterally. Comparison across patients who received the median prosthesis size of 5 (SD 1.3, range 2-8) was inadequately restored by 1.4 mm (p < 0.00001) medially and 3.4 mm (p < 0.00001) laterally.Conclusion: Host anatomy is not routinely restored during TKA. The surgical teaching to aim for an anterior femoral osteotomy close to the anterior cortex will result in understuffing of the PFJ and based on current prosthesis designs, the risk of overstuffing is not as significant as once believed. Future prostheses and surgical techniques should aim to restore not only posterior femoral but also anterior femoral offset.Level Of Evidence: IV, Case series. [ABSTRACT FROM AUTHOR]

Since less invasive approaches for total hip arthroplasty (THA) are promoted, our aim was to compare direct lateral (DLA) and anterolateral approach (ALA) under otherwise identical conditions. Pre - and postoperative x-rays from 200 propensity matched patients (DLA vs. ALA) were evaluated for anatomical reconstruction. Overall, the cup position was within the safe zone in both group while the mean center of rotation (COR) was placed more medial and cranial in both groups compared to preoperative anatomy (p > 0.05). The mean leg elongation was comparable between both approaches (p > 0.05). Postoperatively the WOMAC improved about 90%. This study confirmed that the ALA can be safely used for THA in minimal invasive setting. [ABSTRACT FROM AUTHOR]

Introduction: In total hip arthroplasty (THA), altering the original offset can lead to poor outcome or even complications or revision when the changes are too great. The aim of the present study was to compare femoral offset between short and standard stems. The hypothesis was that the short stems studied provide better control of post-operative femoral offset.Patients and Methods: We retrospectively reviewed 100 consecutive THAs using uncemented optimys™ short stems (Mathys, Bettlach, Switzerland), matched to 100 standard stem THAs performed during the same period. The primary endpoint was femoral offset; secondary endpoints were the limb length and cervico-diaphyseal angle.Results: The mean femoral offset increased by 6.0 ± 7.2 mm overall (p < 0.0001), 4.7 ± 6.7 mm in the short-stem group (p < 0.0001), and 7.2 ± 7.5 mm in the standard stem group (p < 0.0001), with a significant inter-group difference (p = 0.0152). Limb length showed no significant inter-group difference (p = 0.8425). Cervico-diaphyseal angle was increased by surgery overall, and more by standard than by short stems (p < 0.05).Conclusion: Measurement of femoral offset revealed significant lateralization. It is critical that offset should be maintained in THA. The technique we use increases femoral offset, but the present study showed less increase using short than standard stems. These findings must be borne in mind to achieve good clinical outcome. [ABSTRACT FROM AUTHOR]