Arthroscopic hip procedures have increased dramatically over the last decade as equipment and techniques have improved. Patients who require hip arthroscopy for femoroacetabular impingement on occasion require surgery on the contralateral hip. Previous studies have found that younger age of presentation and lower Charlson comorbidity index have higher risk for requiring surgery on the contralateral hip but have not found correlation to anatomic variables. The purpose of this study is to evaluate the factors that predispose a patient to requiring subsequent hip arthroscopy on the contralateral hip. This is an IRB-approved, single surgeon retrospective cohort study from an academic, tertiary referral centre. A chart review was conducted on 310 primary hip arthroscopy procedures from 2009-2020. We identified 62 cases that went on to have a hip arthroscopy on the contralateral side. The bilateral hip arthroscopy cohort was compared to unilateral cohort for sex, age, BMI, pre-op alpha angle and centre edge angle measured on AP pelvis XRay, femoral torsion, traction time, skin to skin time, Tonnis grade, intra-op labral or chondral defect. A p-value <0.05 was deemed significant. Of the 62 patients that required contralateral hip arthroscopy, the average age was 32.7 compared with 37.8 in the unilateral cohort (p = 0.01) and BMI was lower in the bilateral cohort (26.2) compared to the unilateral cohort (27.6) (p=0.04). The average alpha angle was 76.3. 0. in the bilateral compared to 66. 0. in the unilateral cohort (p = 0.01). Skin to skin time was longer in cases in which a contralateral surgery was performed (106.3 mins vs 86.4 mins) (p=0.01). Interestingly, 50 male patients required contralateral hip arthroscopy compared to 12 female patients (p=0.01). No other variables were statistically significant. In conclusion, this study does re-enforce existing literature by stating that younger patients are more likely to require contralateral hip arthroscopy. This may be due to the fact that these patients require increased range of motion from the hip joint to perform activities such as sports where as older patients may not need the same amount of range of motion to perform their activities. Significantly higher alpha angles were noted in patients requiring contralateral hip arthroscopy, which has not been shown in previous literature. This helps to explain that larger CAM deformities will likely require contralateral hip arthroscopy because these patients likely impinge more during simple activities of daily living. Contralateral hip arthroscopy is also more common in male patients who typically have a larger CAM deformity. In summary, this study will help to risk stratify patients who will likely require contralateral hip arthroscopy and should be a discussion point during pre-operative counseling. That offering early subsequent or simultaneous hip arthroscopy in young male patients with large CAMs should be offered when symptoms are mild

Developmental dysplasia of the hip can cause pain and premature osteoarthritis. However, the risk factors and timing for disease progression in young adults are not fully defined. This study identified the incidence and risk factors for contralateral hip pain and surgery after periacetabular osteotomy (PAO) on an index dysplastic hip. Patients followed for 2+ years after unilateral PAO were grouped by eventual contralateral pain or no-pain, based on modified Harris Hip Score, and surgery or no-surgery. Univariate analysis tested group differences in demographics, radiographic measures, and range-of-motion. Kaplan-Meier survival analysis assessed pain development and contralateral hip surgery over time. Multivariate regression identified pain and surgery risk factors. Pain and surgery predictors were further analyzed in Dysplastic, Borderline, and Non-dysplastic subcategories, and in five-degree increments of lateral center edge angle (LCEA) and acetabular inclination (AI). 184 patients were followed for 4.6±1.6 years, during which 51% (93/184) reported hip pain and 33% (60/184) underwent contralateral surgery. Kaplan-Meier analysis predicted 5-year survivorship of 49% for pain development and 66% for contralateral surgery. Painful hips exhibited more severe dysplasia than no-pain hips (LCEA 16.5º vs 20.3º, p<0.001; AI 13.2º vs 10.0º p<0.001). AI was the sole predictor of pain, with every 1° AI increase raising the risk by 11%. Surgical hips also had more severe dysplasia (LCEA 14.9º vs 20.0º, p<0.001; AI 14.7º vs 10.2º p<0.001) and were younger (21.6 vs 24.1 years, p=0.022). AI and a maximum alpha angle ≥55° predicted contralateral surgery. 5 years after index hip PAO, 51% of contralateral hips experience pain and 34% percent are expected to need surgery. More severe dysplasia, based on LCEA and AI, increases the risk of contralateral hip pain and surgery, with AI being a predictor of both outcomes. Knowing these risks can inform patient counseling and treatment planning

Laterality and bilaterality have been reported as prognostic variables in DDH outcomes. However, there is little clarity across the literature on the reporting of laterality in developmental dysplasia of the hip (DDH) due to the variability in severity of the condition. It is widely accepted that the left hip is most frequently affected; however, the true incidence of unilateral left, unilateral right and bilateral cases can be hard to quantify and compare across studies. The purpose of this study was to examine laterality accounting for graded severity in a multicentre, international prospective observational study of infants with hip dysplasia in order to demonstrate the complexity of this issue. A multicentre, prospective database of infants diagnosed with DDH between the ages of 0 and 18 months was analysed from 2010 to April 2015. Patients less than six months were enrolled in the study if at least one hip was frankly dislocated. Patients between 6 and 18 months were enrolled if they had any form of hip dysplasia. Each hip was classified as reduced, dysplastic, dislocatable/subluxable, dislocated reducible or dislocated irreducible. Baseline diagnosis was used to classify patients into a graded laterality category accounting for hip status within the DDH spectrum. A total of 496 patients were included in the analysis; 328 were <6 months old at diagnosis and 168 were between 6 and 18 months old. Of these patients, 421 had at least one frankly dislocated hip. Unilateral left hip dislocations were most common, with 223 patients, followed by unilateral right and bilateral dislocations with 106 and 92 respectively. Stratifying these patients based on status of the contralateral hip, 54 unilateral left and 31 unilateral right dislocated patients also had a dysplastic or unstable contralateral hip. There were significantly fewer bilateral patients in the 6–18 month group (p=0.0005). When classifying laterality by affected hip, bilaterality became the predominant finding, comprising 42% of all patients. The distribution of unilateral left, unilateral right and bilateral cases was greatly impacted by the method of classification. Distinct patterns were seen when considering dislocated hips only, or when considering both dislocated and dysplastic/unstable hips. Findings from this multicentre prospective study demonstrate the necessity to account for the graded severity in hip status when reporting DDH laterality. In order to accurately compare laterality across studies, a standardised, comprehensive classification should be established, as contralateral hip status may impact prognosis and treatment outcomes

The aim of this study was to investigate the incidence of dysplasia in the ‘normal’ contralateral hip in patients with unilateral developmental dislocation of the hip (DDH) and to evaluate the long-term prognosis of such hips. A total of 48 patients (40 girls and eight boys) were treated for late-detected unilateral DDH between 1958 and 1962. After preliminary skin traction, closed reduction was achieved at a mean age of 17.8 months (4 to 65) in all except one patient who needed open reduction. In 25 patients early derotation femoral osteotomy of the contralateral hip had been undertaken within three years of reduction, and later surgery in ten patients. Radiographs taken during childhood and adulthood were reviewed. The mean age of the patients was 50.9 years (43 to 55) at the time of the latest radiological review. In all, eight patients (17%) developed dysplasia of the contralateral hip, defined as a centre-edge (CE) angle < 20° during childhood or at skeletal maturity. Six of these patients underwent surgery to improve cover of the femoral head; the dysplasia improved in two after varus femoral osteotomy and in two after an acetabular shelf operation. During long-term follow-up the dysplasia deteriorated to subluxation in two patients (CE angles 4° and 5°, respectively) who both developed osteoarthritis (OA), and one of these underwent total hip replacement at the age of 49 years. In conclusion, the long-term prognosis for the contralateral hip was relatively good, as OA occurred in only two hips (4%) at a mean follow-up of 50 years. Regular review of the ‘normal’ side is indicated, and corrective surgery should be undertaken in those who develop subluxation. Cite this article: Bone Joint J 2014; 96-B:1161–6

Controversy remains as to whether the contralateral hip should be fixed in patients presenting with unilateral slipped capital femoral epiphysis (SCFE). This study compares the outcomes of those patients who had prophylactic fixation with those who did not. We identified 90 consecutive patients with a mean age of 12.3 years presenting to the study centre with SCFE from a prospective operative database. The patient's notes and radiographs were retrospectively analysed for post-operative complications, re-presentation with a contralateral slip, and the presence of a cam lesion. The mean length of follow-up was 8 years (range 3 to 13). Fifty patients (56%) underwent unilateral fixation and 40 patients underwent bilateral fixation, of which 4 (4%) patients had simultaneous bilateral SCFE and 36 (40%) had prophylactic fixation of the contralateral hip. Twenty-three patients (46%) that underwent unilateral fixation, went onto have contralateral fixation for a further SCFE. Two patients from this group had symptomatic femoracetabular impingement from cam lesions and one patient required a Southwick osteotomy for a severe slip. Five patients (10%) that had unilateral fixation only demonstrated cam lesions on radiographic analysis, being suggestive of an asymptomatic slip. No post-operative complications were observed for the contralateral hip in patients that had prophylactic screw fixation and no cam lesions were identified on radiographic assessment. This study suggests that the contralateral hip in patients presenting with unilateral SCFE should be routinely offered prophylactic fixation to avoid a further slip, which may be severe, and the morbidity associated with a secondary cam lesion

We reviewed, at an average age of 46 years, a series of 61 patients treated for unilateral slipped upper femoral epiphysis. At maturity there had been slipping of the contralateral hip in 11 patients (18%) and another 14 (23%) had originally had evidence of bilateral slipping when the primary radiographs were reviewed. In only two of these 25 patients (8%) was the slipping of the contralateral hip symptomatic. The incidence of early osteoarthritis of the contralateral hip was 7 of 36 with no slip, 5 of 16 with an untreated slip and 1 of 9 with a slip pinned in situ. If all 61 contralateral hips had been prophylactically pinned at the primary admission, 36 of the operations (59%) would have been unnecessary. We recommend that prophylactic pinning of the contralateral hip should not be standard, but that lateral radiography by the Billing technique be repeated every third to fourth month until closure of the growth plate begins. Hips in which a slip occurs should be pinned in situ

Slipped capital femoral epiphysis (SCFE) is the most common pediatric hip disorder. The most devastating complication is development of avascular necrosis of the femoral head. In order to reduce the potential for this complication occurring following delayed contralateral SCFE, there has been consideration in the literature of prophylactic pinning of the contralateral hip. The objective of this study was to determine the cost-effectiveness of this treatment strategy. The outcome probabilities and utilities utilised in a decision analysis of prophylactic pinning of the contralateral hip in SCFE, reported by Kocher et al, were used in this study. Costing data, reported in 2005 Canadian dollars, was obtained from our institution. Using this data, an economic evaluation was performed. The time horizon was four years, so as to follow the adolescents to skeletal maturity. Discounting was performed at 3% per year. Sensitivity analyses were conducted to determine the effect of variation of the outcome probabilities and utilities. In all analyses, prophylactic pinning resulted in cost savings but lower utility, compared to the currently accepted strategy of observation of the contralateral hip. The results were most sensitive to an increase in the probability of a delayed contralateral SCFE to 27%. Using the base case analysis, the incremental cost-effectiveness ratio was $7856.12 per utility gained. Using the most sensitive probability of a delayed contralateral SCFE of 27%, the incremental cost-effectiveness ratio was $27,252.92 per utility gained. The results of this study demonstrated overall cost savings with prophylactic treatment, however the utility was lower than the standard treatment of observation. For both the base case and sensitivity analysis, the incremental cost-effectiveness ratio was less than the accepted threshold of $50,000 per quality adjusted life year gained. It should be noted that the use of a four year time horizon excluded consideration of the costs related to total hip arthroplasty for the sequelae of AVN. A prospective, randomised controlled trial, with an accompanying economic evaluation, is required to definitively answer the question of the cost-effectiveness of this treatment. On the basis of this cost-effectiveness analysis, prophylactic pinning of the contralateral hip in SCFE cannot be recommended. A prospective, randomised controlled trial, with an accompanying economic evaluation, is required to definitively answer the question of the cost-effectiveness of this treatment

58 patients underwent treatment for Slipped Upper Femoral Epiphysis (SUFE) at our unit from 1984 to 2001. 4 (7%) patients had bilateral SUFE at the time of primary admission, 17 (29%) patients were diagnosed with a slip of the contralateral hip at review during adolescence. The remaining 37 patients whose contralateral hips were not operated upon at completion of growth were reviewed at an average follow-up of 8 years (range 2–17) after the primary admission. 13 patients were not available for review, so 24 patients were examined and their hips radiographed. Iowa hip score was used to assess the function of the hips, Antero-posterior and lateral radiographic views were taken to look for evidence of epiphyseal slip and degenerative joint disease. The Calcar Femorale was used as a radiographic landmark to check for a slip. Ahlback’s score was used to grade osteoarthritis. 4 out of 24 patients at the follow-up examination showed displacement of the contralateral femoral head that was greater than 3 standard deviation and was consistent with previously unrecognised physiolysis. 4 contralateral hips showed evidence of butteressing at the site of physeal reminence but the displacement was less than 3 standard deviations and so they were not considered to have slipped. 3 of these hips with buttressing had evidence of Grade I osteoarthritis. Overall incidence of bilateral SUFE in our study, excluding the 13 patients who were not available for follow-up was 25 out of 45 (55%). This real existence of unrecognised contralateral slip, the increased risk of OA in these hips and significant rate of bilaterality, stresses the need to readdress the current mode of management of the contralateral hips in patients treated for unilateral SUFE

Introduction. Although a previous hip fracture is one of the strongest predictors for the next one this risk might be modified by other factors. The goal of this analysis was to compute a simple algorithm to assess the individual risk for a contralateral hip fracture. Materials and methods. The analysis is based on a nationwide population-based Danish cohort study of 84,360 patients experiencing a hip fracture followed-up for 5 years. We a priori defined a set of 17 candidate parameters potentially associated with early contralateral hip fracture. We bootstrapped a stepwise augmentation procedure 10 times and selected five parameters that entered the model in all bootstrapping cycles and computed the individual risk for a contralateral fracture within two, three, and five years after the first incidence. Results. 12,349 patients (14.6%) experienced a contralateral hip fracture within five years. The strength of association were: female gender (Odds Ratio 1.58), alcohol abuse 1.57, living in a single household 1.10, no prescription of bisphosphonates 1.64, and comorbidity and Charlson Score values less than 2 2.20, between 3 and 4 1.76, 5 and more, 1.46 against no comorbidity. The probability of experiencing a second fracture ranged from 3.4% to 25.9%. Discussion. Once this instrument is validated in other cohorts it provides a rational basis for prophylactic augmentation or more aggressive pharmaceutical treatment

Introduction: In total hip arthroplasty, the angle of acetabular component is a critical factor for the postoperative dislocation and the longevity of prostheses. The angle is principally determined in relation to anterior pelvic plane. It is reported that the pelvis tends to tilt posteriorly along with aging. Furthermore, the pelvic tilt might change after THA. The changes might be infiuenced by the hip condition and lumbar lordosis. We measured the pelvic tilt and the lumbar lordosis, and evaluated the effects of contralateral hip and lumbar lordosis on pelvic tilt after THA. Materials and Methods: Fifty-one unilateral patients and 30 bilateral patients were enrolled in this study. The diagnosis was dysplastic osteoarthritis in all patients. In unilateral patients, the hip was affected in one side and the other hip was normal or acetabular dysplasia without symptoms. In bilateral patients, THAs in both hips were done within two months. Pelvic inclination angle (PIA) and lumbar lordotic angle (LLA) were measured on the standing lateral X-rays before operation and 1-month, 6-month and 1-year post-operation. The effects of patient age, BMI, ROM of the hip, preoperative PIA and LLA on the changes of PIA were statistically investigated using multiple linear regression analysis. We divided the patients into three groups with regard to pre-operative PIA (anterior group: PIA < 0, intermediate group: 0 < PIA < 10, posterior group: PIA > 10) and with regard to pre-operative LLA (insufficient group: LLA < 20, moderate group: 20 < LLA < 40, severe group: LLA > 40). Results: Overall, significant factor was only preoperative PIA. In bilateral cases, preoperative PIA and patient age affected the changes of PIA after THA. In patients with severe lordosis, preoperative PIA and LLA were significant factors. PIA increased in anterior tilt group and PIA did not change in intermediate group, while PIA gradually decreased in posterior group. In insufficient lordosis group, PIA remarkably increased after THA compared with that in severe group. Discussion: Pelvic tilt after THA has been reported without considering the conditions of contralateral hip and lumbar spine. By categorizing patients with regard to the conditions of hips and lumbar spine, we can prospect the tendency of the direction of PIA changes. These results indicated that pre-operative PIA was related the changes of PIA in bilateral group. PIA slightly increased in all bilateral patients, PIA tended to close each other in unilateral patients. Further investigation is necessary to prospect the estimated PIA value after THA

Prophylactic fixation of the contralateral hip in cases of unilateral slipped capital femoral epiphysis (SCFE) remains contentious. Our senior author reported a 10 year series in 2006 that identified a rate of subsequent contralateral slip of 25percnt; when prophylactic fixation was not performed. This led to a change in local practice and employment of prophylactic fixation as standard. We report the 10 year outcomes following this change in practice. A prospective study of all patients who presented with diagnosis of SCFE between 2004 and 2014 in our region. Intra-operative complication and post-operative complication were the primary outcomes. 31 patients presented during the study period: 16 male patients and 15 female patients. The mean age was 12.16 (8–16, SD 2.07). 25 patients had stable SCFE and 5 had unstable SCFE. Stability was uncertain in 1 patient. 25 patients had unilateral SCFE and 6 had bilateral SCFE. 24 patients who had unilateral SUFE had contralateral pinning performed. 1 unilateral SCFE did not have contralateral pinning performed as there was partial fusion of physis on contralateral side. In the hips fixed prophylactically there was 1 cases of transient intraoperative screw penetration into the joint and 1 case of minor wound dehiscence. There were no cases or chondrolysis or AVN. There were no further contralateral slips. This change in practice has been adopted with minimal complication. The fixation of the contralateral side is not without risk but by adopting this model the risk of subsequent slip has been reduced from 25percnt; to 0percnt;

In the majority of patients with slipped upper femoral epiphysis only one hip is involved at primary diagnosis. However, the contralateral hip often becomes involved over time. There are no reliable factors predicting a contralateral slip. Whether or not the contralateral hip should undergo prophylactic fixation is a matter of controversy. We present a number of essential points that have to be considered both when choosing to fix the contralateral hip prophylactically as well as when refraining from surgery and instead following the patients with repeat radiographs

Aims

The purpose of this study was to examine whether leg-length discrepancy (LLD) following unilateral total hip arthroplasty (THA) affects the incidence of contralateral head collapse and subsequent THA in patients with bilateral osteonecrosis, and to determine factors associated with subsequent collapse.

Methods

A retrospective review of 80 patients with unilateral slipped capital femoral epiphysis from 1998–2012 was undertaken to determine the outcome of the unaffected hip. All patients were treated with either prophylactic single Richards screw fixation or observation of the uninvolved hip and were followed up for at least 12 months. The unaffected hip of 44 patients (mean age 12.6 years, range 9–17) had simultaneous prophylactic fixation and 36 patients (mean age 13.4 years, range 9–17.4) were managed with observation.

Purpose: Insertion of the femoral stem during total hip arthroplasty provokes a bridge between the proximal femoral forces leading to well-documented bone resorption. A review of the literature concerning the behaviour of the contralateral femur and the spine reveals conflicting data. Some authors report variable bone mineral density of the lumbar spine while the contralateral neck, studied with non-cemented prostheseis in all cases, shows a significant fall in bone density. All patients in these studies needed an unloading period to achieve definitive fixation of the hip prosthesis. The purpose of this study was to assess bone behaviour in the contralateral femur and the lumbar spine after unilateral cemented total hip arthroplasty with immediate postoperative weight bearing.

Material and methods: The study series included 52 patients who underwent unilateral cemented total hip arthroplasty for degenerative hip disease. All were followed with standard x-rays and DPX of the contra-lateral hip and the lumbar spine. These examinations were performed one month before surgery then on D8, M3, M6, one year and two years. Bone mineral density (BMD) was measured in the femoral neck cortical and the L2–L4 trabecularlar bone. Patients were verticalised and encouraged to walk with full weight bearing on the average on day 3 to 4 after surgery.

Results: DPX did not demonstrate any significant decrease in BMD in any of the patients included in this study, neither in the lumbar spine nor in the contralat-eral femoral neck.

Discussion: Several studies in the literature point out the difficulty in recovering bone mass lost after a period of immobilisation or unloading. This bone loss could reach 10% of the bone mass even for short periods of unloading. Furthermore, minimal bone loss, to the order of 2.5% could accelerate the transformation of osteopenia into osteoporosis and increase the risk of fractures. The importance of minimising periods of unloading in older patients is thus evident.

Purpose of study: To test the hypothesis that previous hip involvement leads to earlier presentation and a better outcome for the contra-lateral hip in bilateral Legg-Calve-Perthes’ disease (LCPD).

Method: Case notes and radiographs of 250 patients with LCPD treated by a single surgeon between 1984 and 2003 were retrospectively reviewed. Thirty three patients (4 girls: 29 boys) with a minimum 1 year follow-up were identified with bilateral involvement from a prospectively collected database. Patients were grouped according to age at presentation (Group A-< 6 years; Group B- 6–8 years; Group C-> 8 years). All radiographs were reviewed and consensus was obtained on the presenting Waldenstrom stages. The severity of disease was rated by Catterall and lateral pillar classifications. The outcome was determined by the Stulberg classification. The right hip was the first affected in 25 of the 33 hips.

Results: These are summarized below.

Conclusions: The present report, with 33 patients, is the second largest series of patients with bilateral LCPD to our knowledge. The second hip involvement was milder than the first, but the improvement in outcome was statistically insignificant.

Aims. Hip arthroplasty aims to accurately recreate joint biomechanics. Considerable attention has been paid to vertical and horizontal offset, but femoral head centre in the anteroposterior (AP) plane has received little attention. This study investigates the accuracy of restoration of joint centre of rotation in the AP plane. Methods. Postoperative CT scans of 40 patients who underwent unilateral uncemented total hip arthroplasty were analyzed. Anteroposterior offset (APO) and femoral anteversion were measured on both the operated and non-operated sides. Sagittal tilt of the femoral stem was also measured. APO measured on axial slices was defined as the perpendicular distance between a line drawn from the anterior most point of the proximal femur (anterior reference line) to the centre of the femoral head. The anterior reference line was made parallel to the posterior condylar axis of the knee to correct for rotation. Results. Overall, 26/40 hips had a centre of rotation displaced posteriorly compared to the contralateral hip, increasing to 33/40 once corrected for sagittal tilt, with a mean posterior displacement of 7 mm. Linear regression analysis indicated that stem anteversion needed to be increased by 10.8° to recreate the head centre in the AP plane. Merely matching the native version would result in a 12 mm posterior displacement. Conclusion. This study demonstrates the significant incidence of posterior displacement of the head centre in uncemented hip arthroplasty. Effects of such displacement include a reduction in impingement free range of motion, potential alterations in muscle force vectors and lever arms, and impaired proprioception due to muscle fibre reorientation. Cite this article: Bone Joint Res 2022;11(3):180–188

Aims. This study aimed to compare mortality in trochanteric AO/OTA A1 and A2 fractures treated with an intramedullary nail (IMN) or sliding hip screw (SHS). The primary endpoint was 30-day mortality, with secondary endpoints at 0 to 1, 2 to 7, 8 to 30, 90, and 365 days. Methods. We analyzed data from 26,393 patients with trochanteric AO/OTA A1 and A2 fractures treated with IMNs (n = 9,095) or SHSs (n = 17,298) in the Norwegian Hip Fracture Register (January 2008 to December 2020). Exclusions were made for patients aged < 60 years, pathological fractures, pre-2008 operations, contralateral hip fractures, fractures other than trochanteric A1/A2, and treatments other than IMNs or SHSs. Kaplan-Meier and Cox regression analyses adjusted for type of fracture, age, sex, cognitive impairment, American Society of Anesthesiologists (ASA) grade, and time period were conducted, along with calculations for number needed to harm (NNH). Results. In unadjusted analyses, there was no significant difference between IMN and SHS patient survival at 30 days (91.8% vs 91.1%; p = 0.083) or 90 days (85.4% vs 84.5%; p = 0.065), but higher one-year survival for IMNs (74.5% vs 73.3%; p = 0.031) compared with SHSs. After adjustments, no significant difference in 30-day mortality was found (hazard rate ratio (HRR) 0.94 (95% confidence interval (CI) 0.86 to 1.02(; p = 0.146). IMNs exhibited higher mortality at 0 to 1 days (HRR 1.63 (95% CI 1.13 to 2.34); p = 0.009) compared with SHSs, with a NNH of 556, but lower mortality at 8 to 30 days (HRR 0.89 (95% CI 0.80 to 1.00); p = 0.043). No differences were observed in mortality at 2 to 7 days (HRR 0.94 (95% CI 0.79 to 1.11); p = 0.434), 90 days (HRR 0.95 (95% CI 0.89 to 1.02); p = 0.177), or 365 days (HRR 0.97 (95% CI 0.92 to 1.02); p = 0.192). Conclusion. This study found no difference in 30-day mortality between IMNs and SHSs. However, IMNs were associated with a higher mortality at 0 to 1 days and a marginally lower mortality at 8 to 30 days compared with SHSs. The observed differences in mortality were small and should probably not guide choice of treatment. Cite this article: Bone Joint J 2024;106-B(6):603–612

Aims. The aims of this study were to evaluate the abductor function in moderate and severe slipped capital femoral epiphysis (SCFE), comparing the results of a corrective osteotomy at the base of the femoral neck and osteoplasty with 1) in situ epiphysiodesis for mild SCFE, 2) contralateral unaffected hips, and 3) hips from healthy individuals. Patients and Methods. A total of 24 patients (mean age 14.9 years (. sd. 1.6); 17 male and seven female patients) with moderate or severe SCFE (28 hips) underwent base of neck osteotomy and osteoplasty between 2012 and 2015. In situ epiphysiodesis was performed in seven contralateral hips with mild slip. A control cohort was composed of 15 healthy individuals (mean age 16.5 years (. sd. 2.5); six male and nine female patients). The abductor function was assessed using isokinetic dynamometry and range of abduction, with a minimum one-year follow-up. Results. We found no differences in mean peak abductor torque between the hips that underwent osteotomy and those that received in situ epiphysiodesis (p = 0.63), but the torque was inferior in comparison with contralateral hips without a slip (p < 0.01) and hips from control individuals (p < 0.001). The abduction strength was positively correlated with the range of hip abduction (R = 0.36; p < 0.001). Conclusion. Although the abductor strength was not restored to normal levels, moderate and severe SCFE treated with osteotomy at the base of the femoral neck and osteoplasty showed abductor function similar to in situ epiphysiodesis in hips with less severe displacement. Cite this article: Bone Joint J 2018;100-B:1524–32

Aims. This study aimed to evaluate the accuracy of implant placement with robotic-arm assisted total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH). Methods. The study analyzed a consecutive series of 69 patients who underwent robotic-arm assisted THA between September 2018 and December 2019. Of these, 30 patients had DDH and were classified according to the Crowe type. Acetabular component alignment and 3D positions were measured using pre- and postoperative CT data. The absolute differences of cup alignment and 3D position were compared between DDH and non-DDH patients. Moreover, these differences were analyzed in relation to the severity of DDH. The discrepancy of leg length and combined offset compared with contralateral hip were measured. Results. The mean values of absolute differences (postoperative CT-preoperative plan) were 1.7° (standard deviation (SD) 2.0) (inclination) and 2.5° (SD 2.1°) (anteversion) in DDH patients, and no significant differences were found between non-DDH and DDH patients. The mean absolute differences for 3D cup position were 1.1 mm (SD 1.0) (coronal plane) and 1.2 mm (SD 2.1) (axial plane) in DDH patients, and no significant differences were found between two groups. No significant difference was found either in cup alignment between postoperative CT and navigation record after cup screws or in the severity of DDH. Excellent restoration of leg length and combined offset were achieved in both groups. Conclusion. We demonstrated that robotic-assisted THA may achieve precise cup positioning in DDH patients, and may be useful in those with severe DDH. Cite this article: Bone Joint Res 2021;10(10):629–638