We have investigated the effect of using tranexamic acid (TXA) during peri-acetabular osteotomy (PAO) on peri-operative blood loss and blood transfusion requirements. In addition we analysed whether the use of TXA was associated with an increased risk of venous thromboembolism (VTE) following this procedure. A consecutive series of 96 PAOs, performed by a single surgeon, were reviewed. A total of 48 patients received TXA and 48 did not. The TXA group received a continuous infusion of TXA at a rate of 10 mg/kg/h. The primary outcome measure was the requirement for blood transfusion. Secondary outcomes included total blood loss, the decrease in the level of haemoglobin in the blood, the length of hospital stay, and the complications of this treatment. The mean rate of transfusion was significantly lower in the TXA group (62.5% vs 12.5%, p < 0.001). The mean blood loss was also significantly reduced in the TXA group (1.9 L (standard deviation (. sd. ) 0.9) vs 1.5 L (. sd. 0.7), p < 0.01). No post-operative episodes of VTE were identified in either group. . The use of TXA reduced the blood loss and the rate of transfusion after PAO significantly, without adverse effects such as an increased rate of VTE. Cite this article: Bone Joint J 2015;97-B:1604–7

Peri-acetabular osteotomy is an established surgical treatment for symptomatic acetabular dysplasia in young adults. An anteroposterior radiograph of the pelvis is commonly used to assess the extent of dysplasia as well as to assess post-operative correction. Radiological prognostic factors include the lateral centre-edge angle, acetabular index, extrusion index and the acetabular version. Standing causes a change in the pelvis tilt which can alter certain radiological measurements relative to the supine position. This article discusses the radiological indices used to assess dysplasia and reviews the effects of patient positioning on these indices with a focus on assessment for a peri-acetabular osteotomy. Intra-operatively, fluoroscopy is commonly used and the implications of using fluoroscopy as a modality to assess the various radiological indices along with the effects of using an anteroposterior or posteroanterior fluoroscopic view are examined. Each of these techniques gives rise to a slightly different image of the pelvis as the final image is sensitive to the position of the pelvis and the projection of the x-ray beam. Cite this article: Bone Joint J 2014;96-B:1155–60

Pelvic and acetabular surgery may be associated with significant blood loss because of the vascularity and anatomy of the pelvis. Concerns continue in relation to blood transfusion because of the potential for disease transmission and because of the increasing cost of providing safe blood products. The purpose of this study was to examine in a retrospective fashion the blood transfusion requirements in a consecutive series of patients undergoing peri-acetabular osteotomy for hip dysplasia. Surgery was performed under general anaesthesia with an epidural in place in the majority of cases. A cell saver was not used and no pre operative autologous blood donation was performed. In seven cases one unit of blood was drawn off immediately prior to the operation in the anaesthetic room and re-infused towards the end of the operation. This practice was discontinued when one of these units clotted and could not be re-infused. A post-operative transfusion policy was adopted where an haemoglobin (Hb) concentration of < 7.5 g/dl was an indication for transfusion. There were 19 females and 2 males. The average age was 26.6 (range 14 – 40). The average duration of surgery was 233mins (range 180 – 285min). Pre-operatively the average Hb concentration was 13.68 g/dl (range 12.3 – 16.2 g/dl). Overall 16 patients did not require any cross-matched transfusion. Two patients received one unit of blood and three received two units. If the transfusion policy had been correctly followed, 4 of these patients would not have received cross-matched blood. The average post-op Hb in those not receiving transfusion was 8.6 g/dl (range 7.3 – 9.9 g/dl). This study shows that it is possible to safely perform peri-acetabular osteotomies in most cases without blood transfusion which is important in this group of patients who are generally young and female

Ganz peri-acetabular osteotomy is commonly used to treat symptomatic hip dysplasia. It aims to increase the load bearing contact area of the hip to reduce the risk of subsequent osteoarthritis. In this study we assess the radiographic and clinical results of the procedure since its introduction to our unit. All patients undergoing Ganz osteotomies at our unit were followed up prospectively. Data collected included patient demographics and pre- and post-operative functional scores (Harris and Non-arthritic hip scores). In addition, acetabular correction was evaluated on pre-and post-operative radiographs (using Centre-Edge angle and Tonnis angle). Complications were also noted. Overall 50 procedures were performed between 2007 and 2013 with median follow-up of 3 years (1 – 7 years). The majority of patients (90%) were female. Average age at time of surgery was 29 years (16–49). There were significant improvements in pre- and post-operative median functional scores (Modified Harris Hip Score = 49 versus 64, p=0.001), Non-arthritic Hip Score = 42 versus 56, p=0.007). Median Centre Edge Angle improved from 16 degrees pre-operatively (range = 7–31 degrees) to 30 degrees post-operatively (18–33) degrees), p<0.0001. Similarly, pre-operative Tonnis angle improved from 18 degrees (9–38) to 7 degrees (2–14), p<0.0001. Five patients developed post-operative complications: 2 superficial wound infection, 1deep infection requiring hip washout and antibiotic treatment and 2 patients subsequently requiring total hip replacements. We have shown that the Ganz peri-acetabular osteotomy can be effective for the treatment of painful hip dysplasia improving both functional and radiographic outcomes. However, patient selection is a key factor

Ganz peri-acetabular osteotomy is commonly used to treat symptomatic hip dysplasia. It aims to increase the load bearing contact area of the hip to reduce the risk of subsequent osteoarthritis. In this study we assess the radiographic and clinical results of the procedure since its introduction to our unit. All patients undergoing Ganz osteotomies at our unit were followed up prospectively. Data collected included patient demographics and pre- and post-operative functional scores (Harris and Non-arthritic hip scores). In addition, acetabular correction was evaluated on pre-and post-operative radiographs (using Centre-Edge angle and Tonnis angle). Complications were also noted. Overall 50 procedures were performed between 2007 and 2013 with median follow-up of 3 years (1–7 years). The majority of patients (90%) were female. Average age at time of surgery was 32 years (17–39). There were significant improvements in pre- and post-operative median functional scores (Modified Harris Hip Score = 52 versus 63, p=0.001), Non-arthritic Hip Score = 49 versus 60, p=0.01). Median Centre Edge Angle improved from 15 degrees pre-operatively (range = 8–19 degrees) to 29 degrees post-operatively (22–36 degrees), p=0.02. Similarly, pre-operative Tonnis angle improved from 19 degrees (16–38) to 7 degrees (2–14), p=0.01. Four patients developed post-operative complications: 1 superficial wound infection, 1deep infection requiring hip washout and antibiotic treatment and 2 patients subsequently requiring total hip replacements. We have shown that the Ganz peri-acetabular osteotomy can be effective for the treatment of painful hip dysplasia improving both functional and radiographic outcomes. However, patient selection is a key factor

Aims. To determine whether there is any benefit using a minimally invasive trans-sartorial approach as described by Professor Søballe compared to the ilio-femoral for peri-acetabular osteotomy. Methods. 30 consecutive patients were operated on by a single surgeon. The first 15 underwent an ilio-femoral (I-F) approach whilst the following 15 had a trans-sartorial (T-S) approach. Fixation was achieved with 3 or 4 screws. All other aspects of surgery and rehabilitation were the same. Data was collected prospectively and included operation time, intra-operative blood loss and length of stay. Acetabular correction was measured using the sourcil and centre edge angle (CEA) on pre and post-operative radiographs. Results. Both groups had acceptable radiographic corrections with CEA improving from mean 14.5 to 38.7 degrees (T-S) and 14 to 39 degrees (I-F). The sourcil angle improved from mean 17.8 to 2 degrees (T-S) and 19.5 to −1.5 (I-F). Minimally invasive surgery reduced anaesthetic time by 62 minutes. Haemoglobin loss was reduced by 1 gram/L and there was no requirement for transfusion. Hospital stay reduced by 0.8 days. There were no major adverse complications although two partial femoral neurapraxias were noted early in the series. These fully resolved. Conclusion. We have found significant benefit from changing to minimally invasive PAO. Our patients have smaller wounds, a shorter operative time, reduced bleeding and a shorter length of stay. We found no adverse effects. The time savings have also corresponded to a cost saving for our institution. We recommend this technique although recognise that it has a learning curve and should be initiated by surgeons with previous PAO experience

Reconstructive acetabular osteotomy is a well established and effective procedure in the treatment of acetabular dysplasia. However, the dysplasia is frequently accompanied by intra-articular pathology such as labral tears. We intended to determine whether a concomitant hip arthroscopy with peri-acetabular rotational osteotomy could identify and treat intra-articular pathology associated with dysplasia and thereby produce a favourable outcome. We prospectively evaluated 43 consecutive hips treated by combined arthroscopy and acetabular osteotomy. Intra-operative arthroscopic examination revealed labral lesions in 38 hips. At a mean follow-up of 74 months (60 to 97) the mean Harris hip score improved from 72.4 to 94.0 (p < 0.001), as did all the radiological parameters (p < 0.001). Complications included penetration of the joint by the osteotome in one patient, a fracture of the posterior column in another and deep-vein thrombosis in one further patient. This combined surgical treatment gave good results in the medium term. We suggest that arthroscopy of the hip can be performed in conjunction with peri-acetabular osteotomy to provide good results in patients with symptomatic dysplasia of the hip, and the arthroscopic treatment of intra-articular pathology may alter the progression of osteoarthritis

Introduction

The periacetabular osteotomy (PAO) improves hip joint mechanics in patients with symptomatic dysplasia. As a consequence of the multi-planar acetabular re-orientation, the course of the iliopsoas tendon over the hip may be affected, potentially resulting in iliopsoas tendon-related pain. At present, little information regarding the incidence of iliopsoas-related pathology following PAO exists.

We aimed to identify the incidence of iliopsoas-related pain following PAO. Secondarily, we aimed to identify any risk factors associated with this pathology.

Objective: Severe acetabular dysplasia with established dislocation of the hip represents a common problem in cerebral palsy. Once significant dysplasia is present little remodeling of the acetabulum occurs with femoral osteotomies alone. Pelvic osteotomies should address the problem of acetabular deficiency in order to restore optimal coverage of the femoral head. Standard innominate osteotomies are not recommended for neuromus-cular hip dysplasia. To address the lack of postero-lateral coverage in this population, a modified periacetabular osteotomy was performed.

Methods: Between 1991 and 2000 a total of 44 patients (52 hips) with total body involvement CP underwent this procedure at a mean age of 9,4 yrs. The modification includes only one bicortical cut at the posterior corner at the sciatic notch. The cut extends down to the trira-diate cartilage, if present, and through the former site of the triradiate cartilage after closure of the acetabu-lar growth plate in adolescence. Additional procedures included: open reduction, femoral varus osteotomy, and soft tissue releases. Follow-up included a subjective and clinical evaluation. Radiographic assessment included measurements of the migration percentage and acetab-ular index, evidence of AVN, and premature closure of the triradiate cartilage.

Results: The mean follow-up period for these patients was 3.5 years (1.0 to 8,1 yrs) after surgery, and 70% of the patients had reached skeletal maturity at that time. The median acetabular index improved from 30% pre-operatively to 18% at follow-up. The median migration percentage was 71% preoperatively, and 0 at follow-up. A re-dislocation occurred in 1 hip, and a re-subluxation in another. All other hips were stable and well contained at follow-up. There were 3 hips showing signs of postoperative femoral head defects . Premature closure of the triradiate cartilage was not noted. The caregivers had the impression that the surgery had improved personal care, positioning/transferring, and comfort.

Conclusions: This osteotomy reduces the volume of the elongated acetabulum and provides coverage by articular cartilage. It provides coverage particularly at the posterior part of the acetabulum. Compared to other techniques this modified periacetabular osteotomy has only one posterior cortical cut which extends down to the sciatic notch. Since this cut is cortical, the fragment can be mobilized extensively and it allows placement of a graft and a better posterior coverage.

Obesity is a risk factor for complications following many orthopaedic procedures. The purpose of this study was to investigate whether obesity was an independent risk factor increasing the rate of complications following periacetabular osteotomy (PAO) and to determine whether radiographic correction after PAO was affected by obesity.

We retrospectively collected demographic, clinical and radiographic data on 280 patients (231 women; 82.5% and 49 men; 17.5%) who were followed for a mean of 48 months (12 to 60) after PAO. A total of 65 patients (23.2%) were obese (body mass index (BMI) > 30 kg/m²). Univariate and multivariate analysis demonstrated that BMI was an independent risk factor associated with the severity of the complications. The average probability of a patient developing a major complication was 22% (95% confidence interval (CI) 11.78 to 38.21) for an obese patient compared with 3% (95% CI 1.39 to 6.58) for a non-obese patient The odds of a patient developing a major complication were 11 times higher (95% CI 4.71 to 17.60, p <  0.0001) for an obese compared with a non-obese patient.

Following PAO surgery, there was no difference in radiographic correction between obese and non-obese patients. PAO procedures in obese patients correct the deformity effectively but are associated with an increased rate of complications.

Cite this article: Bone Joint J 2015;97-B:29–34.

Introduction: Peri-acetabular rotational osteotomy is recognized as the non-arthroplastic treatment for Developmental Dysplasia of the Hip (DDH). This procedure has increased in popularity during the last decade. It aims to restore the acetabular cover over the femoral head and thus delay secondary osteoarthritic changes in the hip. Materials and methods: We reviewed 16 patients who underwent peri-acetabular rotational surgery at our hospital. The indication for surgery was DDH in all cases. Reinert’s approach was used for surgical exposure. Two patients underwent a valgus femoral osteotomy at the same time. Mean age was 40 years (range 15–49). The mean follow-up was 46.5 months (range 4–108). The results of the surgery were assessed with radiological indices and a patient satisfaction survey. The radiological indices recorded were Wiberg’s angle, acetabular inclination angle, femoral head extrusion index and Tonnis osteoarthritis grading. Results: The intervention failed to benefit two patients who subsequently required a total hip arthroplasty. Both patients had Tonnis grade 3 osteoarthritis. One patient developed a necrotic skin flap requiring skin grafting. The mean pre-operative Wiberg’s angle was 11 degrees (range −7 to 25) which was corrected to 35 degrees (range 17 to 58). Mean pre-operative acetabular index was 25 degrees (range 14 to 40) which was corrected to 11 degrees (range of 2 to 21). Mean pre-operative femoral head extrusion index was 37 degrees (range 18–50) which was reduced to 14 degrees (range 0–32). In all but the two patients in whom the surgery had failed, patients reported reduction in hip pain. Conclusions: Peri-acetabular rotational osteotomy is a challenging but worthwhile procedure for young patients with DDH. The early results from the procedure are encouraging providing patient selection is appropriate. We would like to initiate a debate to identify the ideal patient for this procedure

Aims

The lateral centre-edge angle (LCEA) is a plain radiological measure of superolateral cover of the femoral head. This study aims to establish the correlation between 2D radiological and 3D CT measurements of acetabular morphology, and to describe the relationship between LCEA and femoral head cover (FHC).

The April 2015 Hip & Pelvis Roundup. 360 . looks at: Goal-directed fluid therapy in hip fracture; Liberal blood transfusion no benefit in the longer term; Repeated measures: increased accuracy or compounded errors?; Peri-acetabular osteotomy safer than perhaps thought?; Obesity and peri-acetabular osteotomy: poor bedfellows; Stress fracture in peri-acetabular osteotomy; Infection and tantalum implants; Highly crosslinked polyethylene really does work

Mixed Reality has the potential to improve accuracy and reduce required dissection for the performance of peri-acetabular osteotomy. The current work assesses initial proof of concept of MR guidance for PAO. A PAO planning module, based on preoperative computed tomography (CT) imaging, allows for the planning of PAO cut planes and repositioning of the acetabular fragment. 3D files (holograms) of the cut planes and native and planned acetabulum positions are exported with the associated spatial information. The files are then displayed on mixed reality head mounted device (HoloLens2, Microsoft) following intraoperative registration using an FDA-cleared mixed reality application designed primary for hip arthroplasty (HipInsight). PAO was performed on both sides of a bone model (Pacific Research). The osteotomies and acetabular reposition were performed in accordance with the displayed holograms. Post-op CT imaging was performed for analysis. Cutting plane-accuracy was evaluated using a best-fit plane and 2D angles (°) between the planned and achieved supra (SA)- and retroacetabular (RA) osteotomy and retroacetabular and ischial osteotomies (IO) were measured. To evaluate the accuracy of acetabular reorientation, we digitized the acetabular rim and calculated the acetabular opening plane. Absolute errors of planned and achieved operative inclination and anteversion (°) of the acetabular fragment, as well as 3D lateral-center-edge (LCE) angles were calculated. The mean absolute difference between the planned and performed osteotomy angles was 3 ± 3°. The mean absolute error between planned and achieved operative anteversion and inclination was 1 ± 0° and 0 ± 0° respectively. Mean absolute error between planned and achieved 3D LCE angle was 0.5 ± 0.7°. Mixed-reality guidance for the performance of pelvic osteotomies and acetabular fragment reorientation was feasible and highly accurate. This solution may improve the current standard of care by enabling reliable and precise reproduction of the desired acetabular realignment

The gold standard treatment of hip dysplasia is a peri-acetabular osteotomy (PAO). Labral tears are seen in the majority of patients presenting with hip dysplasia and diagnosed using Magnetic Resonance Imaging (MRI). The goal was to (1) evaluate utility/value of MRI in patients undergoing hip arthroscopy at time of PAO, and (2) determine whether MRI findings of labral pathology can predict outcome. A prospective randomized controlled trial was conducted at tertiary institutions, comparing patients with hip dysplasia treated with isolated PAO versus PAO with adjunct hip arthroscopy. This study was a subgroup analysis on 74 patients allocated to PAO and adjunct hip arthroscopy (age 26±8 years; 89.2% females). All patients underwent radiographic and MRI assessment using a 1.5-Tesla with or 3-Tesla MRI without arthrography to detect labral or cartilage pathology. Clinical outcome was assessed using international Hip Outcome Tool-33 (iHOT). 74% of patients (55/74) were pre-operatively diagnosed with a labral tear on MRI. Among these, 41 underwent labral treatment (74%); whilst among those without a labral tear on MRI, 42% underwent labral treatment (8/19). MRI had a high sensitivity (84%), but a low specificity (56%) for labral pathology (p=0.053). There was no difference in pre-operative (31.3±16.0 vs. 37.3±14.9; p=0.123) and post-operative iHOT (77.7±22.2 vs. 75.2±23.5; p=0.676) between patients with and without labral pathology on MRI. Value of MRI in the diagnostic work-up of a patient with hip dysplasia is limited. MRI had a high sensitivity (84%), but low specificity (44%) to identify labral pathology in patients with hip dysplasia. Consequently, standard clinical MRI had little value as a predictor of outcome with no differences in PROM scores between patients with and without a labral tear on MRI. Treatment of labral pathology in patients with hip dysplasia remains controversial. The results of this subgroup analysis of a prospective, multi-centre RCT do not show improved outcome among patients with dysplasia treated with labral repair

Our understanding of pre-arthritic hip disease has evolved tremendously but challenges remain in categorizing diagnosis, which ultimately impacts choice of treatments and clinical outcomes. This study aims to report patient reported outcome measures (PROMs) comparing four different condition groups within hip preservation surgery by a group of fellowship-trained surgeons. From 2018 to 2021, 380 patients underwent hip preservation surgery at our center and were classified into five condition groups: dysplasia: 82 (21.6%), femoro-acetabular impingement (FAI): 173 (45.4%), isolated labral tear: 103 (27.1%), failed hip preservation: 20 (5.3%) and history of childhood disease/other: 2 (0.5%). International hip outcomes Tool 12 (IHOT-12), numeric pain score and patient-reported outcomes measurement information system (PROMIS) were collected pre-operatively and at 3 months and 1 year post-operatively, with 94% and 82% follow-up rate respectively. Arthroscopy (75.5%) was the most common procedure followed by peri-acetabular osteotomy (PAO) (22.4%) and surgical dislocation (2.1%). Re-operation rate were respectively 18.3% (15), 5.8% (10), 4.9% (5), 30% (6) and 0%. There were 36 re-operations in the cohort, 14 (39%) for unintended consequences of initial surgery, 10 (28%) for mal-correction leading to a repeat operation, 8 (22%) progression of arthritis, and 4 (11%) for incorrect initial diagnosis/intervention. Most common re-operations were hardware removal 31% (7 PAO, 3 surgical hip dislocation and 1 femoral de-rotational osteotomy), arthroscopy 31% (11) and arthroplasty 28% (10). All groups had significant improvements in their IHOT-12 as well as PROMIS physical and numerical pain scales, except those with failed hip preservation. Dysplasia group showed a slower recovery. Overall, this study demonstrated a clear relation between the condition groups, their respective intervention and the significant improvements in PROMs with isolated labral pathology being a valid diagnosis. Establishing tertiary referral centers for hip preservation and longer follow-up is needed to monitor the overall survivorship of these various procedures

Traditional radiographic criteria might underestimate or fail to detect subtle types of acetabular dysplasia. Acetabular sector angles (ASA) can measure the degree of anterior and posterior coverage of the femoral head on computed tomography (CT). This study aims to determine ASA values at different axial levels in a cohort of (1) asymptomatic, high-functioning hips without underlying hip pathology (controls); and (2) symptomatic, dysplastic hips that underwent periacetabular osteotomy (PAO). Thereby, we aimed to define CT-based thresholds for hip dysplasia and its subtypes. This is an IRB approved cross-sectional study of 51 high functioning, asymptomatic patients (102 hips) (Oxford Hip Score >43), without signs of osteoarthritis (Tönnis grade≤1), who underwent a CT scan of the pelvis (mean age: 52.1±5.5 years; 52.9% females); and 66 patients (72 hips) with symptomatic hip dysplasia treated with peri-acetabular osteotomy (PAO) (mean age: 29.3±7.3 years; 85.9% females). Anterior and posterior acetabular sector angles (AASA & PASA) were measured by two observers at three CT axial levels to determine equatorial, intermediate, and proximal ASA. Inter- and intra-observer reliability coefficient was high (between 0.882–0.992). Cut-off values for acetabular deficiency were determined based on Receiver Operating Characteristic (ROC) curve analysis, area under the curve (AUC) was calculated. The dysplastic group had significantly smaller ASAs compared to the Control Group, AUC was the highest at the proximal and intermediate PASA. Controls had a mean proximal PASA of 162°±17°, with a cut-off value for dysplasia of 137° (AUC: 0.908). At the intermediate level, the mean PASA of controls was 117°±11°, with a cut-off value of 107° (AUC 0.904). Cut-off for anterior dysplasia was 133° for proximal AASA (AUC 0.859) and 57° for equatorial AASA (AUC 0.868). Cut-off for posterior dysplasia was 102° for intermediate PASA (AUC 0.933). Measurement of ASA on CT is a reliable tool to identify dysplastic hips with high diagnostic accuracy. Posterior ASA less than 137° at the proximal level, and 107° at the intermediate level should alert clinicians of the presence of dysplasia

The February 2013 Children’s orthopaedics Roundup. 360 . looks at: ABC treated with suction and curettage; peri-acetabular osteotomy; cast index; Perthes’ disease associated with accidental injury; brachial plexus birth palsy; MRI assessment of DDH; total meniscectomy; and paediatric septic arthritis

Introduction. Acetabular dysplasia is associated with an increased risk of hip pain and early development of osteoarthritis (OA). The Bernese peri-acetabular osteotomy (PAO) is the most well-established technique in the Western world for the treatment of symptomatic acetabular dysplasia. This case-control study aims to assess whether the severity of acetabular dysplasia has an effect on outcome following Peri-Acetabular Osteotomy (PAO) and/or the ability to achieve desired acetabular correction. Patients/Materials & Methods. A prospective, multicentre, longitudinal cohort of consecutive PAOs was reviewed. Of the available 381 cases, 61 hips had pre-PAO radiographic features of lesser-dysplasia [Acetabular-Index (AI)<15° and Lateral-Centre-Edge-Angle (LCEA)>15°) and comprised the ‘study-group’. ‘Study-Group’ was matched for all factors known to influence outcome post-PAO [age, gender, BMI, Tönnis-grade and joint congruency (p=0.6–0.9)] with a ‘Comparison-Group’ of pronounced dysplasia (n=183). Clinical outcomes, complications and the ability to achieve optimum correction (LCEA: 25°–40°/AI: 0°–+10°) were compared. Results. At a mean follow-up of 4(±1.5) years, 3 hips had a THA and 13 underwent further procedures; 21 major complications occurred. The mean improvement in HOOS was 28(±23). No differences in complication- or re-operation- rates were detected between study- and comparison groups (p=0.29). Lesser-dysplastic hips had inferior HOOS compared to pronounced dysplastic hips, both pre- (52Vs.59) and post-operatively (73Vs.78); however, similar improvements were seen. Amongst the lesser dysplastic hips, those that required a femoral osteochondroplasty at PAO had significantly inferior pre-operative HOOS (48±18), compared to those that didn't require an osteochondroplasty (60±17) (p=0.04). Increased ability to achieve optimum acetabular correct was seen (80Vs59%, p=0.4) in the lesser dysplastic hip. Discussion. A PAO is safe and efficacious in the treatment of lesser dysplasia. The mildly dysplastic hips with cam deformity that required concurrent FOCP and PAO, were the most symptomatic. Future studies should aim to optimize diagnosis and management in this challenging, combined deformity cohort

Peripheral nerve injury is an uncommon but serious complication of hip surgery that can adversely affect the outcome. Several studies have described the use of electromyography and intra-operative sensory evoked potentials for early warning of nerve injury. We assessed the results of multimodal intra-operative monitoring during complex hip surgery. We retrospectively analysed data collected between 2001 and 2010 from 69 patients who underwent complex hip surgery by a single surgeon using multimodal intra-operative monitoring from a total pool of 7894 patients who underwent hip surgery during this period. In 24 (35%) procedures the surgeon was alerted to a possible lesion to the sciatic and/or femoral nerve. Alerts were observed most frequently during peri-acetabular osteotomy. The surgeon adapted his approach based on interpretation of the neurophysiological changes. From 69 monitored surgical procedures, there was only one true positive case of post-operative nerve injury. There were no false positives or false negatives, and the remaining 68 cases were all true negative. The sensitivity for predicting post-operative nerve injury was 100% and the specificity 100%. We conclude that it is possible and appropriate to use this method during complex hip surgery and it is effective for alerting the surgeon to the possibility of nerve injury