Explore the vast range of titles available.

Background Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) allows an objective, noninvasive, and longitudinal quantification of biochemical cartilage properties. Although dGEMRIC has been used to monitor the course of cartilage degeneration after periacetabular osteotomy (PAO) for correction of hip dysplasia, such longitudinal data are currently lacking for femoroacetabular impingement (FAI). Questions/purposes (1) How does the mean acetabular and femoral dGEMRIC index change after surgery for FAI at 1-year followup compared with a similar group of patients with FAI treated without surgery? (2) Does the regional distribution of the acetabular and femoral dGEMRIC index change for the two groups over time? (3) Is there a correlation between the baseline dGEMRIC index and the change of patient-reported outcome measures (PROMs) at 1-year followup? (4) Among those treated surgically, can dGEMRIC indices distinguish between intact and degenerated cartilage? Methods We performed a prospective, comparative, nonrandomized, longitudinal study. At the time of enrollment, the patients’ decision whether to undergo surgery or choose nonoperative treatment was not made yet. Thirty-nine patients (40 hips) who underwent either joint-preserving surgery for FAI (20 hips) or nonoperative treatment (20 hips) were included. The two groups did not differ regarding Tönnis osteoarthritis score, preoperative PROMs, or baseline dGEMRIC indices. There were more women (60% versus 30%, p = 0.003) in the nonoperative group and patients were older (36 ± 8 years versus 30 ± 8 years, p = 0.026) and had lower alpha angles (65° ± 10° versus 73° ± 12°, p = 0.022) compared with the operative group. We used a 3.0-T scanner and a three-dimensional dual flip-angle gradient-echo technique for the dGEMRIC technique for the baseline and the 1-year followup measurements. dGEMRIC indices of femoral and acetabular cartilage were measured separately on the initial and followup radial dGEMRIC reformats in direct comparison with morphologic radial images. Regions of interest were placed manually peripherally and centrally within the cartilage based on anatomic landmarks at the clockface positions. The WOMAC, the Hip disability and Osteoarthritis Outcome Score, and the modified Harris hip score were used as PROMs. Among those treated surgically, the intraoperative damage according to the Beck grading was recorded and compared with the baseline dGEMRIC indices. Results Although both the operative and the nonoperative groups experienced decreased dGEMRIC indices, the declines were more pronounced in the operative group (−96 ± 112 ms versus −16 ± 101 ms on the acetabular side and −96 ± 123 ms versus −21 ± 83 ms on the femoral side in the operative and nonoperative groups, respectively; p < 0.001 for both). Patients undergoing hip arthroscopy and surgical hip dislocation experienced decreased dGEMRIC indices; the decline in femoral dGEMRIC indices was more pronounced in hips after surgical hip dislocation (−120 ± 137 ms versus −61 ± 89 ms, p = 0.002). In the operative group a decline in dGEMRIC indices was observed in 43 of 44 regions over time. In the nonoperative group a decline in dGEMRIC indices was observed in four of 44 regions over time. The strongest correlation among patients treated surgically was found between the change in WOMAC and baseline dGEMRIC indices for the entire joint (R = 0.788, p < 0.001). Among those treated nonoperatively, no correlation between baseline dGEMRIC indices and change in PROMs was found. In the posterosuperior quadrant, the dGEMRIC index was higher for patients with intact cartilage compared with hips with chondral lesions (592 ± 203 ms versus 444 ± 205 ms, p < 0.001). Conclusions We found a decline in acetabular, femoral, and regional dGEMRIC indices for the surgically treated group at 1-year followup despite an improvement in all PROMs. We observed a similar but less pronounced decrease in the dGEMRIC index in symptomatic patients without surgical treatment indicating continuous cartilage degeneration. Although treatment of FAI is intended to alter the forces acting across the hip by eliminating impingement, its effects on cartilage biology are not clear. dGEMRIC provides a noninvasive method of assessing these effects. Longer term studies will be needed to determine whether the matrix changes of the bradytrophic cartilage seen here are permanent or clinically important. Level of Evidence Level II, therapeutic study.

Background Computer-assisted surgery (CAS) for cup placement has been developed to improve the functional results and to reduce the dislocation rate and wear after total hip arthroplasty (THA). Previously published studies demonstrated radiographic benefits of CAS in terms of implant position, but whether these improvements result in clinically important differences that patients might perceive remains largely unknown. Questions/purposes We hypothesized that THA performed with CAS would improve 10-year patient-reported outcomes measured by validated scoring tools, reduce acetabular polyethylene wear as measured using a validated radiological method, and increase survivorship. Methods Sixty patients operated on for a THA between April 2004 and April 2005 were randomized into two groups using either the CAS technique or a conventional technique for cup placement. All patient candidates for a THA with the diagnosis of primary arthritis or avascular necrosis were eligible for the CAS procedure and randomly assigned to the CAS group by the Hospital Informatics Department with use of a systematic sampling method. The patients assigned to the freehand cup placement group were matched for sex, age within 5 years, pathological condition, operatively treated side, and body mass index within 3 points. All patients were operated on through an anterolateral approach (patient in the supine position) using cementless implants. In the CAS group, a specific surgical procedure using an imageless cup positioning computer-based navigation system was performed. There were 16 men and 14 women in each group; mean age was 62 years (range, 24–80 years), and mean body mass index was 25 ± 3 kg/m 2 . No patient was lost to followup at 10 years, but five patients have died (two in the CAS group and three in the control group). At the 10-year followup, an independent observer blinded to the type of technique performed patients’ evaluation. Cup positioning was evaluated postoperatively using a CT scan in the two groups with results previously published. At 10 years, we assessed subjective functional outcome and quality of life using validated questionnaires (SF-12, Harris hip score [HHS], Hip injury and Osteoarthritis Outcome Score). Wear rate was then evaluated on standardized radiographs using a previously validated semiautomated computer analogic measurement method (dual circle method). Complications and survivorship were compared between groups. With our available sample size, this study had 80% power to detect a difference of 4 points out of 100 on the HHS at the p < 0.05 level. Results With the numbers available, we found we found no differences between groups regarding HSS at last followup 95.3 ± 5.9 points (CAS group) versus 96.2 ± 4.5 points, a mean difference of 0.9 points (95% confidence interval [CI], −4.3 to 4.6; p = 0.6). There was no difference between the groups in terms of the mean (± SD) acetabular linear wear at 10 years. The mean wear was 0.71 ± 0.6 mm in the CAS group versus 0.77 ± 0.52 mm in the control group, a mean difference of 0.06 mm (95% CI, −0.1 to 0.2; p = 0.54). With the numbers available, there was no difference between the CAS group and the conventional THA groups in terms of survivorship free from aseptic loosening (100%; 95% CI, 100%–95%, versus 100%; 95% CI, 100%–94%; p = 0.3). Conclusions Our observations suggest that CAS used for cup placement does not confer any substantial advantage in function, wear rate, or survivorship at 10 years after THA. Because CAS is associated with added costs and surgical time, future studies need to identify what clinically relevant advantages it offers, if any, to justify its continued use in THA. Level of Evidence Level II, therapeutic study.

Background. The aim of this study is to retrospectively evaluate the efficacy of 3D navigational template for Salter osteotomy of DDH in children. Methods. Thirty-two consecutive patients with DDH who underwent Salter osteotomy were evaluated between July 2014 and August 2017, and they were divided into the conventional group (n=16) and navigation template group (n=16) according to different surgical methods. The corrective acetabular degrees, radiation exposure, and operation time were compared between the two groups. Results. No nerve palsy or redislocation was reported in the navigation template group. Compared with the conventional group, the navigation template group had the advantages of more accurate acetabular degrees, less radiation exposure, and shorter operation time (P<0.05). Meanwhile, the navigation template group achieved a better surgical outcome than the conventional group (McKay, P=0.0293; Severin, P=0.0949). Conclusions. The 3D navigational template for Salter osteotomy of DDH is simple and effective, which could be an alternative approach to improve the Salter osteotomy accuracy and optimize the efficacy.

Background The Movethehip trial investigates the effectiveness of an exercise and patient education intervention for adults with acetabular dysplasia. The intervention involves eight tailored one-to-one sessions with trained providers who employ supportive feedback tools. The present protocol reports a planned process evaluation, which aims to determine how the intervention functions by examining the implementation of the intervention (process, dose and reach), its acceptability, mechanisms of change and the influence of contextual factors. Methods Two hundred trial participants aged 18–50 years will be recruited from a University Hospital in Denmark and randomised to the intervention or control group. Approximately ten providers will deliver the intervention. The process evaluation adopts a concurrent mixed-methods design. The implementation will be assessed using self-report questionnaires (at baseline and 6-month follow-up), training records and semi-structured focus group interviews with intervention providers ( n  = 10) and healthcare managers ( n  = 4–6). The mechanisms of change will be explored through semi-structured one-to-one interviews (at baseline and 6-month follow-up) with 15–20 purposefully sampled participants and by measuring changes in health outcomes (self-reported pain, physical functioning and quality of life completed at baseline and at 3- and 6-month follow-up). Additionally, change will be measured through an explorative examination of associations between dose and change in health outcomes, applying simple linear regression models. The acceptability of the intervention and the influence of contextual factors will be explored through one-to-one participant interviews and focus group interviews with 4–6 healthcare managers. The interviews will focus on expectations, experiences, events, personal understandings and interaction with interpersonal and organisational aspects. Interview data will be analysed using theoretical thematic analyses, and findings will be merged with quantitative data and reported jointly on a theme-by-theme basis. Discussion The process evaluation conducted as part of the MovetheHip trial will illuminate how the intervention functions, and if the intervention is proven effective, the findings of the evaluation will contribute to pinpoint how the intervention may be optimised to facilitate future up-scaling and implementation. Trial registration The MovetheHip protocol was approved by the Committee on Health Research Ethics in the Central Denmark Region. ClinicalTrials, NCT04795843. Registered on 20 March 2021.

Background Although the success of the Bernese periacetabular osteotomy (PAO) has been reported for primary dysplasia, there is no study analyzing the radiographic, functional, and gait results of the PAO to correct residual hip dysplasia after previous pelvic surgery. Questions/purposes We assessed (1) radiographic and (2) functional and gait outcomes of patients treated with a PAO after previous pelvic surgery (PPSx) and compared their results with results of patients with no previous surgery (NPSx) to determine whether the PAO was equally effective in patients with revision pelvic surgery. Methods Twenty-nine dysplastic hips in 26 patients (average age, 16.3 years) were included: 13 in the PPSx group and 13 in the NPSx group. Radiographic parameters included the lateral center-edge angle, acetabular index, and femoral head extrusion index measured preoperatively and at 6 months and 1 year. We assessed preoperative and postoperative function using the Harris hip score (HHS). Preoperative and postoperative gait analysis included the hip abductor impulse. Results Improvements in groups were seen from preoperatively to 1 year postoperatively for the lateral center-edge angle, acetabular index, and femoral head extrusion index without differences between groups. The modified HHSs improved at 6 months and were maintained at 1 year for patients in both groups without differences between groups. The hip abductor impulse returned to preoperative values at 6 months in the NPSx group but not until 1 year in the PPSx group. Conclusions The Bernese PAO is effective in providing similar final radiographic and functional results, however, a trend toward decreased hip flexion and abduction power at 1 year was seen with previous pelvic surgery. Level of Evidence Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Background Numerous factors influence total hip arthroplasty (THA) stability including surgical approach and soft tissue tension, patient compliance, and component position. One long-held tenet regarding component position is that cup inclination and anteversion of 40° ± 10° and 15° ± 10°, respectively, represent a “safe zone” as defined by Lewinnek that minimizes dislocation after primary THA; however, it is clear that components positioned in this zone can and do dislocate. Questions/purposes We sought to determine if these classic radiographic targets for cup inclination and anteversion accurately predicted a safe zone limiting dislocation in a contemporary THA practice. Methods From a cohort of 9784 primary THAs performed between 2003 and 2012 at one institution, we retrospectively identified 206 THAs (2%) that subsequently dislocated. Radiographic parameters including inclination, anteversion, center of rotation, and limb length discrepancy were analyzed. Mean followup was 27 months (range, 0–133 months). Results The majority (58% [120 of 206]) of dislocated THAs had a socket within the Lewinnek safe zone. Mean cup inclination was 44° ± 8° with 84% within the safe zone for inclination. Mean anteversion was 15° ± 9° with 69% within the safe zone for anteversion. Sixty-five percent of dislocated THAs that were performed through a posterior approach had an acetabular component within the combined acetabular safe zones, whereas this was true for only 33% performed through an anterolateral approach. An acetabular component performed through a posterior approach was three times as likely to be within the combined acetabular safe zones (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.1–1.6) than after an anterolateral approach (OR, 0.4; 95% CI, 0.2–0.7; p < 0.0001). In contrast, acetabular components performed through a posterior approach (OR, 1.6; 95% CI, 1.2–1.9) had an increased risk of dislocation compared with those performed through an anterolateral approach (OR, 0.8; 95% CI, 0.7–0.9; p < 0.0001). Conclusions The historical target values for cup inclination and anteversion may be useful but should not be considered a safe zone given that the majority of these contemporary THAs that dislocated were within those target values. Stability is likely multifactorial; the ideal cup position for some patients may lie outside the Lewinnek safe zone and more advanced analysis is required to identify the right target in that subgroup. Level of Evidence Level III, therapeutic study.

Background Since its first description in 1984, periacetabular osteotomy (PAO) has become an accepted treatment for hip dysplasia. The 30-year survivorship with this procedure has not been reported. Because these patients are often very young at the time of surgery, long-term followup and identification of factors associated with poor outcome could help to improve patient selection. Questions/purposes Looking at the initial group of patients with hip dysplasia undergoing PAO at the originator’s institution, we asked: (1) What is the cumulative 30-year survival rate free from conversion to THA, radiographic progression of osteoarthritis, and/or a Merle d’Aubigné-Postel score < 15? (2) Did hip function improve and pain decrease? (3) Did radiographic osteoarthritis progress? (4) What are the factors associated with one or more of the three endpoints: THA, radiographic progression of osteoarthritis, and/or Merle d’Aubigné-Postel score < 15? Methods We retrospectively evaluated the first 63 patients (75 hips) who underwent PAO for hip dysplasia between 1984 and 1987. At that time, hip dysplasia was the only indication for PAO and no patients with acetabular retroversion, the second indication for a PAO performed today, were included. During that period, no other surgical treatment for hip dysplasia in patients with closed triradiate cartilage was performed. Advanced osteoarthritis (≥ Grade 2 according to Tönnis) was present preoperatively in 18 hips (24%) and 22 patients (23 hips [31%]) had previous femoral and/or acetabular surgery. Thirty-nine patients (42 hips [56%]) were converted to a THA and one patient (one hip [1%]) had hip fusion at latest followup. Two patients (three hips [4%]) died from a cause unrelated to surgery 6 and 16 years after surgery with an uneventful followup. From the remaining 21 patients (29 hips), the mean followup was 29 years (range, 27–32 years). Of those, five patients (six hips [8%]) did not return for the most recent followup and only a questionnaire was available. The cumulative survivorship of the hip according to Kaplan-Meier was calculated if any of the three endpoints, including conversion to THA, progression of osteoarthritis by at least one grade according to Tönnis, and/or a Merle d’Aubigné-Postel score < 15, occurred. Hip pain and function were assessed with Merle d’Aubigné-Postel score, Harris hip score, limp, and anterior and posterior impingement tests. Progression of radiographic osteoarthritis was assessed with Tönnis grades. A Cox regression model was used to calculate factors associated with the previously defined endpoints. Results The cumulative survivorship free from conversion to THA, radiographic progression of osteoarthritis, and/or Merle d’Aubigné-Postel score < 15 was 29% (95% confidence interval, 17%-42%) at 30 years. No improvement was found for either the Merle d’Aubigné-Postel (15 ± 2 versus 16 ± 2, p = 0.144) or Harris hip score (83 ± 11 versus 85 ± 17, p = 0.602). The percentage of a positive anterior impingement test (39% versus 14%, p = 0.005) decreased at 30-year followup, whereas the percentage of a positive posterior impingement test (14% versus 3%, p = 0.592) did not decrease. The percentage of positive limp decreased from preoperatively 66% to 18% at 30-year followup (p < 0.001). Mean osteoarthritis grade (Tönnis) increased from preoperatively 0.8 ± 1 (0–3) to 2.1 ± 1 (0–3) at 30-year followup (p < 0.001). Ten factors associated with poor outcome defined as THA, radiographic progression of osteoarthritis, and/or Merle d’Aubigné-Postel score < 15 were found: preoperative age > 40 years (hazard ratio [HR] 4.3 [3.7–4.9]), a preoperative Merle d’Aubigné-Postel score < 15 (HR 4.1 [3.5–4.6]), a preoperative Harris hip score < 70 (HR 5.8 [5.2–6.4]), preoperative limp (HR 1.7 [1.4–1.9]), presence of a preoperative positive anterior impingement test (HR 3.6 [3.1–4.2]), presence of a preoperative positive posterior impingement test (HR 2.5 [1.7–3.2]), a preoperative internal rotation of < 20° (HR 4.3 [3.7–4.9]), a preoperative Tönnis Grade > 1 (HR 5.7 [5.0–6.4]), a postoperative anterior coverage > 27% (HR 3.2 [2.5–3.9]), and a postoperative acetabular retroversion (HR 4.8 [3.4–6.3]). Conclusions Thirty years postoperatively, 29% of hips undergoing PAO for hip dysplasia can be preserved, but more than 70% will develop progressive osteoarthritis, pain, and/or undergo THA. Periacetabular osteotomy is an effective technique to treat symptomatic hip dysplasia in selected and young patients with closed triradiate cartilage. Hips with advanced joint degeneration (osteoarthritis Tönnis Grade ≥ 2) should not be treated with PAO. Postoperative anterior acetabular overcoverage or postoperative acetabular retroversion were associated with decreased joint survival. Level of Evidence Level III, therapeutic study.

Background Sitting pelvic tilt dictates the proximity of the rim of the acetabulum to the proximal femur and, therefore, the risk of impingement in patients undergoing total hip arthroplasty (THA). Sitting position is achieved through a combination of lumbar spine segmental motions and/or femoroacetabular articular motion in the lumbar-pelvic-femoral complex. Multilevel degenerative disc disease (DDD) may limit spine flexion and therefore increase femoroacetabular flexion in patients having THAs, but this has not been well characterized. Therefore, we measured standing and sitting lumbar-pelvic-femoral alignment in patients with radiographic signs of DDD and in patients with no radiographic signs of spine arthrosis. Questions/purposes We asked: (1) Is there a difference in standing and sitting lumbar-pelvic-femoral alignment before surgery among patients undergoing THA who have no radiographic signs of spine arthrosis compared with those with preexisting lumbar DDD? (2) Do patients with lumbar DDD experience less spine flexion moving from a standing to a sitting position and therefore compensate with more femoroacetabular flexion compared with patients who have no radiographic signs of arthrosis? Methods Three hundred twenty-five patients undergoing primary THA had preoperative low-dose EOS spine-to-ankle lateral radiographs in standing and sitting positions. Eighty-three patients were excluded from this study for scoliosis (39 patients), spondylolysis (15 patients), not having five lumbar vertebrae (7 patients), surgical or disease fusion (11 patients), or poor image quality attributable to high BMI (11 patients). In the remaining 242 of 325 patients (75%), two observers categorized the lumbar spine as either without radiographic arthrosis or having DDD based on defined radiographic criteria. Sacral slope, lumbar lordosis, and proximal femur angles were measured, and these angles were used to calculate lumbar spine flexion and femoroacetabular flexion in standing and sitting positions. Patients were aligned in a standardized sitting position so that their femurs were parallel to the floor to achieve approximately 90° of apparent hip flexion. Results After controlling for age, sex, and BMI, we found patients with DDD spines had a mean of 5° more posterior pelvic tilt (95% CI, −2° to −8° lower sacral slope angles; p < 0.01) and 7° less lumbar lordosis (95% CI, −10° to −3°; p < 0.01) in the standing position compared with patients without radiographic arthrosis. However, in the sitting position, patients with DDD spines had 4° less posterior pelvic tilt (95% CI, 1°–7° higher sacral slope angles; p = 0.02). From standing to sitting position, patients with DDD spines experienced 10° less spine flexion (95% CI, −14° to −7°; p < 0.01) and 10° more femoroacetabular flexion (95% CI, 6° to 14°; p < 0.01). Conclusions Most patients undergoing THA sit in a similar range of pelvic tilt, with a small mean difference in pelvic tilt between patients with DDD spines and those without radiographic arthrosis. However, in general, the mechanism by which patients with DDD of the lumbar spine achieve sitting differs from those without spine arthrosis with less spine flexion and more femoroacetabular flexion. Clinical Relevance When planning THA, it may be important to consider which patients sit with less posterior pelvic tilt and those who rotate their pelvises forward to achieve a sitting position, as both mechanisms will limit or reduce the functional anteversion of the acetabular component in a patient with a THA. Our study provides some additional perspective on normal relationships between pelvic tilt and femoroacetabular flexion, but further research might better characterize this relationship in outliers and the possible implications for posterior instability after THA.

The 2016 Warwick Agreement on femoroacetabular impingement (FAI) syndrome was convened to build an international, multidisciplinary consensus on the diagnosis and management of patients with FAI syndrome. 22 panel members and 1 patient from 9 countries and 5 different specialties participated in a 1-day consensus meeting on 29 June 2016. Prior to the meeting, 6 questions were agreed on, and recent relevant systematic reviews and seminal literature were circulated. Panel members gave presentations on the topics of the agreed questions at Sports Hip 2016, an open meeting held in the UK on 27–29 June. Presentations were followed by open discussion. At the 1-day consensus meeting, panel members developed statements in response to each question through open discussion; members then scored their level of agreement with each response on a scale of 0–10. Substantial agreement (range 9.5–10) was reached for each of the 6 consensus questions, and the associated terminology was agreed on. The term ‘femoroacetabular impingement syndrome’ was introduced to reflect the central role of patients' symptoms in the disorder. To reach a diagnosis, patients should have appropriate symptoms, positive clinical signs and imaging findings. Suitable treatments are conservative care, rehabilitation, and arthroscopic or open surgery. Current understanding of prognosis and topics for future research were discussed. The 2016 Warwick Agreement on FAI syndrome is an international multidisciplinary agreement on the diagnosis, treatment principles and key terminology relating to FAI syndrome.The Warwick Agreement on femoroacetabular impingement syndrome has been endorsed by the following 25 clinical societies: American Medical Society for Sports Medicine (AMSSM), Association of Chartered Physiotherapists in Sports and Exercise Medicine (ACPSEM), Australasian College of Sports and Exercise Physicians (ACSEP), Austian Sports Physiotherapists, British Association of Sports and Exercise Medicine (BASEM), British Association of Sport Rehabilitators and Trainers (BASRaT), Canadian Academy of Sport and Exercise Medicine (CASEM), Danish Society of Sports Physical Therapy (DSSF), European College of Sports and Exercise Physicians (ECOSEP), European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA), Finnish Sports Physiotherapist Association (SUFT), German-Austrian-Swiss Society for Orthopaedic Traumatologic Sports Medicine (GOTS), International Federation of Sports Physical Therapy (IFSPT), International Society for Hip Arthroscopy (ISHA), Groupo di Interesse Specialistico dell’A.I.F.I., Norwegian Association of Sports Medicine and Physical Activity (NIMF), Norwegian Sports Physiotherapy Association (FFI), Society of Sports Therapists (SST), South African Sports Medicine Association (SASMA), Sports Medicine Australia (SMA), Sports Doctors Australia (SDrA), Sports Physiotherapy New Zealand (SPNZ), Swedish Society of Exercise and Sports Medicine (SFAIM), Swiss Society of Sports Medicine (SGMS/SGSM), Swiss Sports Physiotherapy Association (SSPA).

Background Detailed recognition of the three-dimensional (3-D) deformity in acetabular dysplasia is important to help guide correction at the time of reorientation during periacetabular osteotomy (PAO). Common plain radiographic parameters of acetabular dysplasia are limited in their ability to characterize acetabular deficiency precisely. The 3-D characterization of such deficiencies with low-dose CT may allow for more precise characterization. Questions/purposes The purposes of this study were (1) to determine the variability in 3-D acetabular deficiency in acetabular dysplasia; (2) to define subtypes of acetabular dysplasia based on 3-D morphology; (3) to determine the correlation of plain radiographic parameters with 3-D morphology; and (4) to determine the association of acetabular dysplasia subtype with patient clinical characteristics including sex, range of motion, and femoral version. Methods Using our hip preservation database, we identified 153 hips (148 patients) that underwent PAO from October 2013 to July 2015. Among those, we noted 103 hips in 100 patients with acetabular dysplasia (lateral center-edge angle < 20°) and who had a Tönnis grade of 0 or 1. Eighty-six patients (86%) underwent preoperative low-dose pelvic CT scans at our institution as part of the preoperative planning for PAO. It is currently our standard to obtain preoperative low-dose pelvic CT scans (0.75–1.25 mSv, equivalent to three to five AP pelvis radiographs) on all patients before undergoing PAO unless a prior CT scan was performed at an outside institution. Hips with a history of a neuromuscular disorder, prior trauma, prior surgery, radiographic evidence of joint degeneration, ischemic necrosis, or Perthes-like deformities were excluded. Fifty hips in 50 patients met inclusion criteria and had CT scans available for review. These low-dose CT scans of 50 patients with symptomatic acetabular dysplasia undergoing evaluation for surgical planning of PAO were then retrospectively studied. CT scans were analyzed quantitatively for acetabular coverage, relative to established normative data for acetabular coverage, as well as measurement of femoral version. The cohort included 45 females and five males with a mean age of 26 years (range, 13–49 years). Results Lateral acetabular deficiency was present in all patients, whereas anterior deficiency and posterior deficiency were variable. Three patterns of acetabular deficiency were common: anterosuperior deficiency (15 of 50 [30%]), global deficiency (18 of 50 [36%]), and posterosuperior deficiency (17 of 50 [34%]). The presence of a crossover sign or posterior wall sign was poorly predictive of the dysplasia subtype. With the numbers available, males appeared more likely to have a posterosuperior deficiency pattern (four of five [80%]) compared with females (13 of 45 [29%], p = 0.040). Hip internal rotation in flexion was significantly greater in anterosuperior deficiency (23° versus 18°, p = 0.05), whereas external rotation in flexion was significantly greater in posterosuperior deficiency (43° versus 34°, p = 0.018). Acetabular deficiency pattern did not correlate with femoral version, which was variable across all subtypes. Conclusions Three patterns of acetabular deficiency commonly occur among young adult patients with mild, moderate, and severe acetabular dysplasia. These patterns include anterosuperior, global, and posterosuperior deficiency and are variably observed independent of femoral version. Recognition of these distinct morphologic subtypes is important for diagnostic and surgical treatment considerations in patients with acetabular dysplasia to optimize acetabular correction and avoid femoroacetabular impingement.