How useful are indirect radiographic measurements of hip instability in borderline hip dysplasia? An MRI-based comparison to a healthy cohort.

PURPOSE: Symptomatic hips with borderline hip dysplasia (BHD) morphology pose a challenge in differentiating stable from unstable hips. The current study aims to compare indirect radiographic signs of instability in a symptomatic BHD population to those in a healthy cohort. METHODS: The study group consisted of patients with a lateral centre-edge angle (LCEA) with values 18° ≤ LCEA < 25° who underwent corrective periacetabular osteotomy (PAO) and reported an improvement in patient-reported outcome measures (PROMs). The comparison group consisted of a healthy cohort of athletes who did not complain of any hip-related symptoms and who had normal values of their hip morphological parameters (LCEA, acetabular index (AI°), alpha angle (α°), femoral version, acetabular version). Indirect signs of instability consisting of the femoro-epiphyseal acetabular roof index (FEAR), iliocapsularis-to-rectus-femoris (IC/RF) ratio and labral dimensions (height-to-length ratio) were assessed in both groups. Partial Pearson correlation, logistic multiple regression analysis and Receiver-Operating Characteristic (ROC) curve analysis were performed to determine correlations, as well as the sensitivity and specificity of these signs to differentiate between healthy hips and BHD. RESULTS: On binary logistic multiple regression analysis, the FEAR Index was the only independent predictor to differentiate between BHD and healthy hips (p < 0.001). The IC/RF ratio did not achieve significance. The calculated area under the curve (AUC) was 0.93 (0.87 - 0.99, CI 95%, p < 0.001) for the FEAR Index and 0.81 (0.70 - 0.92, CI 95%, p < 0.001) for the height-length ratio. Using the predefined cut-off values (dysplastic-FEAR Index ≥ 5° or labral height-to-length ratio ≤ 0.5), 27% sensitivity/100% specificity and 20% sensitivity/ 100% specificity, were achieved. ROC analysis provided the following new thresholds: FEAR Index ≥ -5° (73% sensitivity/97% specificity); labral height-to-length ratio ≤ 0.8 (70% sensitivity, 79% specificity). CONCLUSION: In our cohort, the FEAR index was an independent parameter that could differentiate between borderline dysplastic and asymptomatic hips. The previously published values for both the FEAR index and labral hypertrophy ratio had a poor sensitivity in differentiating symptomatic unstable BHD from healthy hips. The cut-off values of ≥ -5° (FEAR index) and ≤ 0.8 (labral height-to-length ratio) provided acceptable sensitivity and specificity when comparing to morphological healthy hips.

Perioperative Intravenous Dexamethasone Significantly Reduces Postoperative Opioid Requirement and Nausea After Unilateral Elective Hip Arthroscopy: A Randomized Double-blinded Placebo-controlled Trial.

BACKGROUND: Previous studies have shown that dexamethasone has a positive effect on postoperative pain control, opioid consumption, nausea, and vomiting and length of hospital stay after arthroplasty surgery. PURPOSE/HYPOTHESIS: The purpose of this study was to assess whether adding perioperative dexamethasone to our current pain regimen after hip arthroscopy is more effective than a placebo. It was hypothesized that dexamethasone would reduce postoperative pain, reduce opioid consumption, improve subjective pain and nausea scores, and reduce the number of vomiting events. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A total of 50 patients requiring unilateral elective hip arthroscopy were randomized to receive intravenous dexamethasone immediately before induction of anesthesia and at 8 am on the first postoperative day (2 ×12 mg) or a placebo (sodium chloride 0.9%). The patient, the surgeons, the treating anesthesiologist, and the involved nursing and physical therapy personnel were blinded to group assignment. The primary outcome was postoperative pain, and secondary outcomes were opioid consumption and nausea scores-assessed using a translated revised version of the American Pain Society Patient Outcome Questionnaire 6 hours postoperatively and on days 1 and 2-and vomiting events. A clinical follow-up was performed 12 weeks postoperatively to assess adverse events. RESULTS: The mean age at inclusion was 29 years in both groups. Postoperative pain levels did not differ significantly in most instances. Opioid requirements during the hospitalization in the dexamethasone group were significantly lower than those in the placebo group (31.96 ± 20.56 mg vs 51.43 ± 38 mg; P = .014). Significantly fewer vomiting events were noted in the dexamethasone group (0.15 ± 0.59 vs 0.65 ± 0.91; P = .034). Descriptive data and surgical parameters did not differ significantly. CONCLUSION: Perioperative intravenous dexamethasone significantly reduced postoperative opioid consumption by 40% without compromising pain level and safety, as no corticosteroid-related side effects were observed. Dexamethasone may be a valuable adjuvant to a multimodal systemic pain regimen after hip arthroscopy. REGISTRATION: NCT04610398 (ClinicalTrials.gov identifier).

High femoral offset as a risk factor for aseptic femoral component loosening in cementless primary total hip arthroplasty.

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.

Influence of offset on osseointegration in cementless total hip arthroplasty: A finite element study.

Early aseptic loosening is caused by deficient osteointegration of the femoral stem due to increased micromotions and represents a common mode of failure in uncemented total hip arthroplasty (THA). This study hypothesized that a higher femoral offset, a smaller stem size and obesity increase femoral micromotion, potentially resulting in early aseptic loosening. A finite element analysis was conducted based on computed tomography segmented model of four patients who received a THA with a triple-tapered straight stem (Size 1, 3, 6). The influence of femoral stem offset (short neck, standard, lateral), head length (S to XXL), femoral anteversion and obesity during daily activities of fast walking and stair climbing was analyzed. The micromotions for the femoral stem zones were compared to a threshold representing a value above which only partial osseointegration is expected. The minimum femoral offset configuration compared to the maximum offset configuration (short neck stem, S head vs. lateral stem, XXL head) leads to a relative mean micromotion increase of 24% for the upper stem zone. Increasing the body weight (body mass index 30-35 kg/m2) increases the micromotion by 20% for all stem zones. The obese population recorded threshold-exceeding micromotions for stem sizes 1 and 3 for all offset configurations during stair climbing. Higher femoral offset, a smaller stem size, and higher loading due to obesity lead to an increase in micromotion between the prosthesis and proximal femur and represent a risk configuration for impaired osseointegration of a triple-tapered straight stem, especially when these three factors are present simultaneously.

Gluteus maximus tendon transfer as a salvage option for painful chronic hip abductor insufficiency: clinical and MRI results with a minimum follow-up of 24 months.

INTRODUCTION: Chronic hip abductor insufficiency is a rare debilitating condition. In cases refractory to conservative treatment and not amenable to direct repair an augmentation becomes necessary. The preferred salvage method at our institution is augmentation with the anterior third of the gluteus maximus tendon. The aim of this study is to describe the results of 8 patients, treated for painful chronic hip abductor insufficiency with gluteus maximus muscle transfer, after a minimal follow-up of 24 months including a full clinical and MRI evaluation of the hip abductors pre- and postoperatively. METHODS: We retrospectively reviewed a consecutive series of 8 patients who were surgically managed for painful chronic hip abductor insufficiency. All patients had a Trendelenburg sign, impaired muscle strength (M ⩽ 3) as well as a complete avulsion of the hip abductors with marked fatty degeneration (⩾3). Pain levels, muscle strength, functional scores as well as a postoperative MRI was obtained after a minimal follow-up of 24 months. RESULTS: The mean age of the patients was 69 years, mean follow-up was 35 (26-54) months. Pain was significantly reduced postoperatively to VAS 2.5 from VAS 5 (p = 0.046). Trendelenburg sign remained positive in all patients and hip abductor strength did not improve significantly from 2.4 to 3.1 (p = 0.19). Complete healing of the transferred tendon was confirmed by MRI in all patients at last follow-up. CONCLUSIONS: In the setting of painful chronic hip abductor insufficiency refractory to conservative treatment with advanced muscle degeneration without the possibility of a direct reconstruction the gluteus maximus tendon transfer significantly decreased pain. The effect on hip abductor strength and patient-reported functional outcome scores is limited. Despite the modest results it remains our preferred salvage treatment option for lack of better alternatives. Larger studies are necessary to confirm these findings.

No Difference in Patient-Reported Outcomes for Periacetabular Osteotomy and Hip Arthroscopy With Capsular Plication in the Setting of Borderline Hip Dysplasia: A Propensity-Matched Multicenter Study With Minimum 5-Year Follow-Up.

PURPOSE: To compare minimum 5-year patient-reported outcome measures after hip arthroscopy (HA) and periacetabular osteotomy (PAO) for borderline hip dysplasia. METHODS: Hips with a lateral center-edge angle (LCEA) between 18° and less than 25° that underwent either PAO or HA were selected from 2 institutions. The exclusion criteria were as follows: LCEA less than 18°, Tönnis osteoarthritis grade greater than 1, prior hip surgical procedures, active inflammatory disease, Workers' Compensation, and concomitant surgery. Patients underwent propensity matching based on age, sex, body mass index, and Tönnis osteoarthritis grade. Patient-reported outcome measures included the modified Harris Hip Score, as well as calculation of the minimal clinically important difference, patient acceptable symptom state, and maximum outcome improvement satisfaction threshold. Preoperative radiographic predictors included comparison of the Femoro-epiphyseal Acetabular Roof index and ligamentum teres lesions. RESULTS: A total of 28 PAO patients underwent propensity matching to 49 HA patients. The 2 groups were similar in terms of mean age, sex, preoperative body mass index, and LCEA. The PAO group had a longer mean follow-up period (95.8 months vs 81.3 months, P = .001). The mean Femoro-epiphyseal Acetabular Roof index was significantly lower preoperatively in the HA group (P < .001). The 2 groups showed similar and significant improvements in the mean modified Harris Hip Score from preoperatively to latest follow-up (P < .001). The relative risk of subsequent surgery in the PAO group was 3.49 (P = .024), mostly attributed to hardware removal (25%). The revision rate was 3.6% in the PAO group and 8.2% in the HA group (P = .65). One patient in the PAO group required revision HA for intra-articular adhesions. Three of the patients requiring revision in the HA group underwent PAO because of persistent pain, and one underwent revision HA alone. Conversion to total hip arthroplasty was required in 1 patient in the HA group and no patients in the PAO group. CONCLUSIONS: Both PAO and HA with capsular plication provide borderline hip dysplasia patients with clinically significant improvements and low revision rates at a minimum of 5 years postoperatively. LEVEL OF EVIDENCE: Level III, retrospective, comparative therapeutic trial.

The effect of experimentally induced gluteal muscle weakness on joint kinematics, reaction forces, and dynamic balance performance during deep bilateral squats.

Squatting is a common daily activity and fundamental exercise in resistance training and closed kinetic chain programs. The aim of this study was to investigate the effects of an experimentally induced weakness of the gluteal muscles on joint kinematics, reactions forces (JRFs), and dynamic balance performance during deep bilateral squats in healthy young adults. Ten healthy adults received sequential blocks of (1) branch of the superior gluteal nerve to the tensor fasciae latae (SGNtfl) muscle, (2) superior gluteal nerve (SGN), and (3) inferior gluteal nerve (IGN) on the dominant right leg. At the control condition and following each block, the participants were instructed to perform deep bilateral squats standing on two force plates. Hip, knee, ankle, and pelvis kinematics did not differ significantly following iatrogenic weakness of gluteal muscles. The most important finding was the significant differences in JRFs following SGN and IGN block, with the affected hip, patellofemoral, and ankle joint demonstrating lower JRFs, whereas the contralateral joints demonstrated significantly higher JRFs, especially the patellofemoral joint which demonstrated an average maximum difference of 1.43 x body weight compared with the control condition. When performing a deep bilateral leg squat under SGN and IGN block, the subjects demonstrated an increased center of pressure (CoP) range and standard deviation (SD) in mediolateral compared with the control condition. These results imply that squat performance changes significantly following weakness of gluteal muscles and should be considered when assessing and training athletes or patients with these injuries.

Augmented reality-guided pelvic osteotomy of Ganz: feasibility in cadavers.

INTRODUCTION: The periacetabular osteotomy is a technically demanding procedure with the goal to improve the osseous containment of the femoral head. The options for controlled execution of the osteotomies and verification of the acetabular reorientation are limited. With the assistance of augmented reality, new possibilities are emerging to guide this intervention. However, the scientific knowledge regarding AR navigation for PAO is sparse. METHODS: In this cadaveric study, we wanted to find out, if the execution of this complex procedure is feasible with AR guidance, quantify the accuracy of the execution of the three-dimensional plan, and find out what has to be done to proceed to real surgery. Therefore, an AR guidance for the PAO was developed and applied on 14 human hip cadavers. The guidance included performance of the four osteotomies and reorientation of the acetabular fragment. The osteotomy starting points, the orientation of the osteotomy planes, as well as the reorientation of the acetabular fragment were compared to the 3D planning. RESULTS: The mean 3D distance between planned and performed starting points was between 9 and 17 mm. The mean angle between planned and performed osteotomies was between 6° and 7°. The mean reorientation error between the planned and performed rotation of the acetabular fragment was between 2° and 11°. CONCLUSION: The planned correction can be achieved with promising accuracy and without serious errors. Further steps for a translation from the cadaver to the patient have been identified and must be addressed in future work.

Quantifying cup overhang after total hip arthroplasty: standardized measurement using reformatted computed tomography and association of overhang distance with iliopsoas impingement.

OBJECTIVES: Currently, there is no standardized measurement method for evaluating cup overhang (CO) in patients undergoing total hip arthroplasty (THA). We propose a novel, standardized method of measuring overhang distance in patients following primary total hip arthroplasty (THA) on computed tomography (CT) images after multiplanar reformation and compare it to a previously proposed measurement method on sagittal CT images. MATERIALS AND METHODS: This retrospective study included patients who underwent primary THA with an anterior approach. Patients with cup overhang (CO) and iliopsoas impingement (IPI) were identified by clinical and imaging data. Uncorrected overhang distance (ODu) was evaluated on orthogonal sagittal CT images while corrected overhang distance (ODc) was evaluated on reformatted sagittal CT images corrected for pelvic rotation and aligned with the plane of the cup face. RESULTS: Out of 220 patients with THA, 23 patients (10.4%) with CO and 16 patients (7.3%) with IPI were identified. CO was significantly associated to IPI (p < 0.001). The inter- and intrareader agreement was almost perfect for ODc (κ = 0.822, κ = 0.850), whereas it was fair and moderate for ODu (κ = 0.391, κ = 0.455), respectively. The discriminative ability of ODc was excellent (area under the curve (AUC) = 0.909 (95% confidence interval (CI) 0.784-1.000)) in the receiver operating characteristic analysis. Conversely, AUC for ODu was poor, measuring 0.677 (95% CI 0.433-0.921). CONCLUSION: We implemented a novel measurement method for CT images reformatted at the plane of the cup face to assess overhang distance in patients with CO following THA. CLINICAL RELEVANCE STATEMENT: While further validation is necessary, the proposed method is characterized by its high reproducibility and might be used to predict the occurrence of iliopsoas impingement in patients with cup overhang following total hip arthroplasty. KEY POINTS: • A novel, standardized method of measuring cup overhang distance in patients following primary total hip arthroplasty on CT images is proposed. • Cup overhang was associated to iliopsoas impingement. The proposed method was reproducible and showed excellent prediction of iliopsoas impingement in patients with cup overhang. • This method can be implemented in clinical practice when assessing CT images of patients with cup overhang for iliopsoas impingement.

Combined Anteversion Threshold to Avoid Anterior Dislocation in Primary Total Hip Arthroplasty Performed Through the Direct Anterior Approach.

BACKGROUND: Component malposition in total hip arthroplasty (THA) can lead to dislocation, early implant failure, and revision surgery. As the surgical approach might affect the targeted combined anteversion (CA) of THA components, the present study aimed to evaluate the optimal CA threshold to avoid anterior dislocation in primary THA performed through a direct anterior approach (DAA). METHODS: A total of 1,176 THAs in 1,147 consecutive patients (men: 593, women: 554) who had an average age of 63 years (range, 24 to 91) and a mean body mass index of 29 (range, 15 to 48) were identified. Medical records were reviewed for dislocation, whereas postoperative radiographs were assessed to measure the acetabular inclination and CA using a previously validated radiographic method. RESULTS: An anterior dislocation occurred in 19 patients at an average of 40 days postoperatively. The average CA in patients who did and did not have a dislocation was 66 ± 8° and 45 ± 11°, respectively (P < .001). In 5 of 19 of the patients, a THA was performed for secondary osteoarthritis and 17 of 19 had a 28-mm femoral head. A CA ≥ 60° yielded a sensitivity of 93% and specificity of 90% for predicting an anterior dislocation in the present cohort. A CA ≥ 60° was associated with a significantly higher risk of anterior dislocation (odds ratio = 75.6; P < .001) compared to patients who had a CA<60 points. CONCLUSION: The optimal CA to avoid anterior dislocations in THA performed through the DAA should be less than 60°. LEVEL OF EVIDENCE: Cross-sectional study, Level III.

Femoro-Epiphyseal Acetabular Roof (FEAR) Index Values on Anteroposterior Pelvic Radiographs Significantly Increase With Hip Adduction and Decrease With Abduction.

PURPOSE: To investigate the impact of hip adduction and abduction on the femoro-epiphyseal acetabular roof (FEAR) index using conventional anteroposterior pelvic radiographs of patients with borderline hip dysplasia (BHD). METHODS: Patients with BHD (lateral center edge angle [LCEA] with values of 18° ≤ LCEA <25°) and who were subject to periacetabular osteotoym were selected from a consecutive retrospective cohort from January 2009 to January 2016. The hip ad-/abduction (adduction handled as negative values) and the FEAR index (lateral opening angles handled as positive values) were measured in the initially standardized acquired pelvic radiographs. Thereafter, using surgical planning software, different degrees of hip adduction and abduction were simulated from 20° of adduction to 30° of abduction, and the FEAR index was measured at each position. Pearson correlation was used to identify a potential correlation between the hip ad-/abduction and the FEAR index. RESULTS: Eighty-nine hips were included. Initial radiographs showed unintentional mean ad-/abduction of -5.3° ± 3.1° (range, -14° to 2°). The mean FEAR index at the initial ad-/abduction angle was -3.6° ± 7.2° (range, -18.0° to 16.0°) and was significantly different from neutral position (0° of ad-/abduction) -9.2° ± 7.0° (range, -27.0° to 10.0°) (P < .001). The FEAR index was negatively correlated to the hip ad-/abduction angle (r = 1, P < .001), with lower values for the FEAR index with the hip in abduction. CONCLUSIONS: Significant differences in FEAR index measurements were observed depending on hip ad-/abduction on pelvic radiographs. A linear change of the FEAR index of 5° per 5° of hip adduction or abduction could be demonstrated, with adduction resulting in increasing and abduction in decreasing values for the FEAR index. LEVEL OF EVIDENCE: Level III, diagnostic study.

Automatic 3D Postoperative Evaluation of Complex Orthopaedic Interventions.

In clinical practice, image-based postoperative evaluation is still performed without state-of-the-art computer methods, as these are not sufficiently automated. In this study we propose a fully automatic 3D postoperative outcome quantification method for the relevant steps of orthopaedic interventions on the example of Periacetabular Osteotomy of Ganz (PAO). A typical orthopaedic intervention involves cutting bone, anatomy manipulation and repositioning as well as implant placement. Our method includes a segmentation based deep learning approach for detection and quantification of the cuts. Furthermore, anatomy repositioning was quantified through a multi-step registration method, which entailed a coarse alignment of the pre- and postoperative CT images followed by a fine fragment alignment of the repositioned anatomy. Implant (i.e., screw) position was identified by 3D Hough transform for line detection combined with fast voxel traversal based on ray tracing. The feasibility of our approach was investigated on 27 interventions and compared against manually performed 3D outcome evaluations. The results show that our method can accurately assess the quality and accuracy of the surgery. Our evaluation of the fragment repositioning showed a cumulative error for the coarse and fine alignment of 2.1 mm. Our evaluation of screw placement accuracy resulted in a distance error of 1.32 mm for screw head location and an angular deviation of 1.1° for screw axis. As a next step we will explore generalisation capabilities by applying the method to different interventions.

Factors influencing patient-reported outcomes following periacetabular osteotomy and open osteochondroplasty in the setting of borderline hip dysplasia.

Aims: This study reports mid-term outcomes after periacetabular osteotomy (PAO) exclusively in a borderline hip dysplasia (BHD) population to provide a contrast to published outcomes for arthroscopic surgery of the hip in BHD. Methods: We identified 42 hips in 40 patients treated between January 2009 and January 2016 with BHD defined as a lateral centre-edge angle (LCEA) of ≥ 18° but < 25°. A minimum five-year follow-up was available. Patient-reported outcomes (PROMs) including Tegner score, subjective hip value (SHV), modified Harris Hip Score (mHHS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were assessed. The following morphological parameters were evaluated: LCEA, acetabular index (AI), α angle, Tönnis staging, acetabular retroversion, femoral version, femoroepiphyseal acetabular roof index (FEAR), iliocapsularis to rectus femoris ratio (IC/RF), and labral and ligamentum teres (LT) pathology. Results: The mean follow-up was 96 months (67 to 139). The SHV, mHHS, WOMAC, and Tegner scores significantly improved (p < 0.001) at last follow-up. According to SHV and mHHS, there were three hips (7%) with poor results (SHV < 70), three (7%) with a fair score (70 to 79), eight (19%) with good results (80 to 89), and 28 (67%) who scored excellent (> 90) at the last follow-up. There were 11 subsequent operations: nine implant removals due to local irritation, one resection of postoperative heterotopic ossification, and one hip arthroscopy for intra-articular adhesions. No hips were converted to total hip arthroplasty at last follow-up. The presence of preoperative labral lesions or LT lesions did not influence any PROMs at last follow-up. From the three hips that had poor PROMs, two have developed severe osteoarthritis (> Tönnis II), presumably due to surgical overcorrection (postoperative AI < -10°). Conclusion: PAO is reliable in treating BHD with favourable mid-term outcomes. Concomitant LT and labral lesions did not negatively influence outcomes in our cohort. Technical accuracy with avoidance of overcorrection is essential in achieving successful outcomes.

A novel method for evaluating combined component anteversion in total hip arthroplasty on cross-table lateral hip radiographs.

INTRODUCTION: Accurate measurement of combined component anteversion (CA) is important in evaluating the radiographic outcomes following total hip arthroplasty (THA). The aim of the present study was to evaluate the accuracy and reliability of a novel radiographic method in estimating CA in THA. MATERIALS AND METHODS: The radiographs and computer tomography of patients who underwent a primary THA were retrospectively reviewed, to measure the radiographic CA (CAr), defined as the angle between a line connecting the center of the femoral head to the most anterior rim of the acetabular cup and a line connecting the center of the femoral head to the base of the femoral head to allow a comparison with the CA measured on the CT (CACT). Subsequently, a computational simulation was performed to evaluate the effect of cup anteversion, inclination, stem anteversion, and leg rotation on the CAr and develop a formula that would correct the CAr according to the acetabular cup inclination based on the best-fit equation. RESULTS: In the retrospective analysis of 154 THA, the average CAr_cor, and CACT were 53 ± 11° and 54 ± 11° (p > 0.05), respectively. A strong correlation was found between CAr and CACT (r = 0.96, p < 0.001), with an average bias of - 0.5° between CAr_cor and CACT. In the computational simulation, the CAr was strongly affected by the cup anteversion, inclination, stem anteversion, and leg rotation. The formula to convert the CAr to CA_cor was: CA-cor = 1.3*Car - (17* In (Cup Inclination) - 31. CONCLUSION: The combined anteversion measurement of THA components on the lateral hip radiograph is accurate and reliable, implying that it could be routinely used postoperatively but also in patients with persistent complaints following a THA. LEVEL OF EVIDENCE: Cross-sectional study, Level III.

Hip arthroscopy versus total hip arthroplasty-A study on patients with obesity above 40 years of age.

Patients older than 40 years with a body-mass-index (BMI) >30 kg/m2 , a femoroacetabular-impingement (FAI) and little cartilage damage are a challenge for hip surgeons. Hip-arthroscopy (HAS) or conservative therapy until a total hip arthroplasty (THA) is needed are possible treatments. Our research purpose was to compare the clinical results and complication/reoperation rate after HAS and THA in patients with obesity over 40 years. This retrospective study includes a consecutive series of patients with obesity (BMI >30 kg/m2 ) who underwent HAS (19 hips) and THA (37 hips) over 40 years of age between 2007 and 2013 at our institution with a minimum of 12-months follow-up. Outcome measures were WOMAC (Western Ontario und McMaster Universities Arthritis Index), subjective-hip-value (SHV), residual complaints and the reoperation rate. Patient data and scores were collected pre-operative, 12 months post-operatively and at the last follow-up. Both groups showed a comparable age (mean 48 years). Regarding SHV-Scores the THA-group shows continuous significant improvements. Reaching 87% (range 50%-100%), the HAS-group showed in case of the SHV no significant change after 1 year and an improvement from preoperative to the last follow-up reaching 72% (range 30%-100%) at the last follow-up. Residual groin pain was significant higher in the HAS-group. Two deep infections (5.4%) requiring reoperations were reported in the THA-group. The conversion rate to THA after a mean time of 60 months was 26% (5 of 19). Patients with obesity over 40 years demonstrated inferior SHV, more often residual pain and revision surgery after HAS, when compared to THA at short-term, with conversions rate of one fourth. However, THA in this patient group showed high infection rate of 5%. This information is relevant for counselling above-mentioned patients.

Three-dimensional analysis of functional femoral antetorsion and the position of the greater trochanter in high-grade patellofemoral dysplastic knees.

BACKGROUND: The relationship between functional femoral antetorsion, the greater trochanter (GT) position and anatomical antetorsion has been demonstrated in patients with a primary hip pathology. However, the functional antetorsion and GT position have not been analyzed in patellofemoral dysplastic knees. The aim of this study was to develop a three-dimensional (3D) measurement to quantify the functional femoral antetorsion and position of the GT and to analyze these measurements in a cohort of high-grade patellofemoral dysplastic knees. METHOD: A 3D measurement was developed to analyze functional antetorsion and the axial position of the GT and assessed in 100 cadaveric femora. For validity and repeatability testing, inter- and intra-observer reliability were determined using intraclass correlation coefficients (ICCs). These measurements were then evaluated in a cohort of 19 high-grade patellofemoral dysplastic knees (Dejour type C, D). The relationship between anatomical antetorsion, functional antetorsion and GT position were reported. RESULTS: Inter- and intra-reader reliability for 3D functional antetorsion and axial position of the GT demonstrated a minimum ICC of 0.96 (P < 0.001). Anatomical and functional antetorsion demonstrated a highly linear relationship (R2 = 0.878; P < 0.001) in high-grade patellofemoral dysplastic knees. The mean difference between anatomical and functional antetorsion decreased with increasing anatomical antetorsion (R2 = 0.25; P = 0.031, indicating a more anterior position of the GT relative to the femoral neck axis. CONCLUSION: In high-grade patellofemoral dysplastic knees, the GT is located more anteriorly, relative to the femoral neck axis, with increasing anatomical antetorsion and correction osteotomy may result in an excessively anterior position of the GT.

Total hip arthroplasty through the direct anterior approach for sequelae of Legg-Calvé-Perthes disease.

INTRODUCTION: Due to multiplanar deformities of the hip, total hip arthroplasty (THA) for sequelae of Legg-Calvé-Perthes disease (LCPD) is often technically demanding. This study aimed to compare the clinical and radiographic outcomes of patients with sequelae of LCPD undergoing THA through the direct anterior approach (DAA) and non-anterior approaches to the hip. METHODS: All patients with sequelae of LCPD who underwent primary THA between 2004 and 2018 (minimum follow-up: 2 years) were evaluated and separated into two groups: THA through the DAA (Group AA), or THA through non-anterior approaches to the hip (Group non-AA). Furthermore, a consecutive control group of patients undergoing unilateral THA through the DAA for primary hip osteoarthritis (Group CC) was retrospectively reviewed for comparison. RESULTS: Group AA comprises 14 hips, group non-AA 17 hips and group CC 30 hips. Mean follow-up was 8.6 (± 5.2; 2-15), 9.0 (± 4.6; 3-17) and 8.1 (± 2.2; 5-12) years, respectively. At latest follow-up, Harris Hip Score was 90 (± 20; 26-100), 84 (± 15; 57-100), and 95 (± 9; 63-100) points, respectively. Overall, 6 patients treated for LCPD (each 3 patient in the AA and non-AA group) developed postoperative sciatic nerve palsy, of which only one was permanent. Complication-related revision rate at the latest follow-up was 15% in the AA-group and 25% in the non-AA group, respectively. CONCLUSION: THA through the DAA might be a credible option for the treatment of sequelae of LCPD with comparable complication rates and functional outcomes to non-anterior approaches.

Study protocol: short against long antibiotic therapy for infected orthopedic sites - the randomized-controlled SALATIO trials.

BACKGROUND: Few studies address the appropriate duration of post-surgical antibiotic therapy for orthopedic infections; with or without infected residual implants. We perform two similar randomized-clinical trials (RCT) to reduce the antibiotic use and associated adverse events. METHODS: Two unblinded RCTs in adult patients (non-inferiority with a margin of 10%, a power of 80%) with the primary outcomes "remission" and "microbiologically-identical recurrences" after a combined surgical and antibiotic therapy. The main secondary outcome is antibiotic-related adverse events. The RCTs allocate the participants between 3 vs. 6 weeks of post-surgical systemic antibiotic therapy for implant-free infections and between 6 vs. 12 weeks for residual implant-related infections. We need a total of 280 episodes (randomization schemes 1:1) with a minimal follow-up of 12 months. We perform two interim analyses starting approximately after 1 and 2 years. The study approximatively lasts 3 years. DISCUSSION: Both parallel RCTs will enable to prescribe less antibiotics for future orthopedic infections in adult patients. TRIAL REGISTRATION: ClinicalTrial.gov NCT05499481. Registered on 12 August 2022. PROTOCOL VERSION: 2 (19 May 2022).

Can pre-operative intraarticular injection predict pain relief after total hip arthroplasty?

BACKGROUND: To study if pain relief after injection and arthroplasty correlate. METHODS: A retrospective cohort study included consecutive patients (n = 88; median age 64 (interquartile range (IQR) 22) years, 49 (56%) females) that received fluoroscopic-guided intra-articular hip injection with contrast agent, anaesthetic (diagnostic), and corticosteroid (therapeutic) before implantation of primary total hip arthroplasty. Pain scores were assessed pre-injection, post-injection after 15 min (diagnostic phase) at first clinical follow up (therapeutic phase; median 2 (IQR 2) months), and postoperatively (last follow up (median 15 (IQR 5) months)). Responders had reduction in pain score ≥ 20 (numeric rating scale 0-100) points. The primary outcome was the same (or inverse) response to injection and arthroplasty. RESULTS: The median pain scores were higher pre-injection (68 (IQR 30) points) compared to the diagnostic phase (18 (IQR 40) points; p < 0.001), therapeutic phase (50 (IQR 40) points; p < 0.001), and post-operatively (2 (IQR 15) points; p < 0.001). On the one hand, 69 (78%) cases had the same response in the diagnostic phase and post-operatively (rho = 0.58; p < 0.001; sensitivity 83%); on the other hand 32 (36%) cases had the same response in the therapeutic phase and post-operatively (rho = 0.25; p < 0.001; sensitivity 33%). Furthermore, 57% and 91% of patients had an even better response post-operatively than in the diagnostic and therapeutic phases. CONCLUSIONS: Pre-operative intraarticular injection can predict pain relief after primary total hip arthroplasty. A positive response to hip arthroplasty may be better predicted by the response to local anaesthetic (diagnostic phase) than corticosteroids. Most patients (91%) with osteoarthritis may expect better pain relief after arthroplasty compared to the therapeutic phase after injection.

No relevant mechanical leg axis deviation in the frontal and sagittal planes is to be expected after subtrochanteric or supracondylar femoral rotational or derotational osteotomy.

PURPOSE: The purpose of this study was to investigate if one level of corrective femoral osteotomy (subtrochanteric or supracondylar) bears an increased risk of unintentional implications on frontal and sagittal plane alignment in a simulated clinical setting. METHODS: Out of 100 cadaveric femora, 23 three-dimensional (3-D) surface models with femoral antetorsion (femAT) deformities (> 22° or < 2°) were investigated, and femAT normalized to 12° with single plane rotational osteotomies, perpendicular to the mechanical axis of the femur. Change of the frontal and sagittal plane alignment was expressed by the mechanical lateral distal femoral angle (mLDFA) and the posterior distal femoral angle (PDFA), respectively. The influence of morphologic factors of the femur [centrum-collum-diaphyseal (CCD) angle and antecurvatum radius (ACR)] were assessed. Furthermore, position changes of the lesser (LT) and greater trochanters (GT) in the frontal and sagittal plane compared to the hip centre were investigated. RESULTS: Mean femoral derotation of the high-antetorsion group (n = 6) was 12.3° (range 10-17°). In the frontal plane, mLDFA changed a mean of 0.1° (- 0.06 to 0.3°) (n.s.) and - 0.3° (- 0.5 to - 0.1) (p = 0.03) after subtrochanteric and supracondylar osteotomy, respectively. In the sagittal plane, PDFA changed a mean of 1° (0.7 to 1.1) (p = 0.03) and 0.3° (0.1 to 0.7) (p = 0.03), respectively. The low-antetorsion group (n = 17) was rotated by a mean of 13.8° (10°-23°). mLDFA changed a mean of - 0.2° (- 0.5° to 0.2°) (p < 0.006) and 0.2° (0-0.5°) (p < 0.001) after subtrochanteric and supracondylar osteotomy, respectively. PDFA changed a mean of 1° (- 2.3 to 1.3) (p < 0.01) and 0.5° (- 1.9 to 0.3) (p < 0.01), respectively. The amount of femAT correction was associated with increased postoperative deviation of the mechanical leg axis (p < 0.01). Using multiple regression analysis, no other morphological factors were found to influence mLDFA or PDFA. Internal rotational osteotomies decreased the ischial-lesser trochanteric space by < 5 mm in both the frontal and sagittal plane (p < 0.001). CONCLUSIONS: In case of femAT correction of ≤ 20°, neither subtrochanteric nor supracondylar femoral derotational or rotational osteotomies have a clinically relevant impact on frontal or sagittal leg alignment. A relevant deviation in the sagittal (but not frontal plane) might occur in case of a > 25° subtrochanteric femAT correction. LEVEL OF EVIDENCE: IV.