Aims. A borderline dysplastic hip can behave as either stable or unstable and this makes surgical decision making challenging. While an unstable hip may be best treated by acetabular reorientation, stable hips can be treated arthroscopically. Several imaging parameters can help to identify the appropriate treatment, including the Femoro-Epiphyseal Acetabular Roof (FEAR) index, measured on plain radiographs. The aim of this study was to assess the reliability and the sensitivity of FEAR index on MRI compared with its radiological measurement. Patients and Methods. The technique of measuring the FEAR index on MRI was defined and its reliability validated. A retrospective study assessed three groups of 20 patients: an unstable group of ‘borderline dysplastic hips’ with lateral centre edge angle (LCEA) less than 25° treated successfully by periacetabular osteotomy; a stable group of ‘borderline dysplastic hips’ with LCEA less than 25° treated successfully by impingement surgery; and an asymptomatic control group with LCEA between 25° and 35°. The following measurements were performed on both standardized radiographs and on MRI: LCEA, acetabular index, femoral anteversion, and FEAR index. Results. The FEAR index showed excellent intraobserver and interobserver reliability on both MRI and radiographs. The FEAR index was more reliable on radiographs than on MRI. The FEAR index on MRI was lower in the stable borderline group (mean -4.2° (. sd. 9.1°)) compared with the unstable borderline group (mean 7.9° (. sd. 6.8°)). With a FEAR index cut-off value of 2°, 90% of patients were correctly identified as stable or unstable using the radiological FEAR index, compared with 82.5% using the FEAR index on MRI. The FEAR index was a better predictor of instability on plain radiographs than on MRI. Conclusion. The FEAR index measured on MRI is less reliable and less sensitive than the FEAR index measured on radiographs. The cut-off value of 2° for radiological FEAR index predicted hip stability with 90% probability. Cite this article: Bone Joint J 2019;101-B:1578–1584

We present a new CT-based method which measures cover of the femoral head in both normal and dysplastic hips and allows assessment of acetabular inclination and anteversion. A clear topographical image of the head with its covered area is generated. We studied 36 normal and 39 dysplastic hips. In the normal hips the mean cover was 73% (66% to 81%), whereas in the dysplastic group it was 51% (38% to 64%). The significant advantage of this technique is that it allows the measurements to be standardised with reference to a specific anatomical plane. When this is applied to assessing cover in surgery for dysplasia of the hip it gives a clearer understanding of where the corrected hip stands in relation to normal and allows accurate assessment of inclination and anteversion

We investigated differences in the location and mode of labral tears between dysplastic hips and hips with femoroacetabular impingement (FAI). We also investigated the relationship between labral tear and adjacent cartilage damage. We retrospectively studied 72 symptomatic hips (in 68 patients: 19 men and 49 women) with radiological evidence of dysplasia or FAI on high-resolution CT arthrography. The incidence and location of labral tears and modes of tear associated with the base of the labrum (Mode 1) or body of the labrum (Mode 2) were compared among FAI, mildly dysplastic and severely dysplastic hips. The locations predominantly involved with labral tears were different in FAI and mild dysplastic hips (anterior and anterosuperior zones) and in severely dysplastic hips (anterosuperior and superior zones) around the acetabulum. Significant differences were observed in the prevalence of Mode 1 versus Mode 2 tears in FAI hips (72% (n = 13) vs 28% (n = 5)) and severe dysplastic hips (25% (n = 2) vs 75% (n = 6)). The frequency of cartilage damage adjacent to Mode 1 tears was significantly higher (42% (n = 14)) than that adjacent to Mode 2 tears (14% (n = 3)). Hip pathology is significantly related to the locations and modes of labral tears. Mode 1 tears may be a risk factor for the development of adjacent acetabular cartilage damage. Cite this article: Bone Joint J 2013;95-B:1320–5

Developmental dysplasia of the hip (DDH) represents a heterogeneous group of deformities that are commonly associated with secondary osteoarthritis. Affected hips may require total hip arthroplasty (THA) for endstage disease and these cases can present unique challenges for the reconstructive surgeon. While the severity of deformity varies greatly, optimizing THA can be challenging even in the “mildly” dysplastic hip. These disorders are commonly characterised by acetabular deficiency with inadequate coverage of the anterolateral femoral head and proximal femoral abnormalities including excessive femoral antetorsion, coxa valga and femoral stenosis. In more severe cases, major femoral head subluxation or dislocation can add additional complexity to the procedure. In addition to the primary deformities of DDH, secondary deformities from previous acetabular or proximal femoral osteotomies may also impact the primary THA. Primary THA in the DDH hip can be optimised by detailed understanding of the bony anatomy, careful pre-operative planning, and an appropriate spectrum of techniques and implants for the given case. This presentation will review the abnormal hip morphologies encountered in the dysplastic hip and will focus on the more challenging aspects of THA. These include acetabular reconstruction of the severely deficient socket and in the setting of total dislocation, femoral implant procedures combined with corrective osteotomy or shortening, and issues related to arthroplasty in the setting of previous pelvic osteotomy. Despite the complexity of reconstruction for various dysplastic variants the clinical outcomes and survivorship of these procedures are good to excellent for most patients. Nevertheless, more complex procedures are associated with an increased complication rate and this should be considered in the surgical decision-making process

We compared the dynamic instability of 25 dysplastic hips in 25 patients using triaxial accelerometry before and one year after periacetabular osteotomy. We also evaluated the hips clinically using the Harris hip score and assessed acetabular orientation by radiography before surgery and after one year. The mean overall magnitude of acceleration was significantly reduced from 2.30 m/s. 2. (. sd. 0.57) before operation to 1.55 m/s. 2. (. sd. 0.31) afterwards. The mean Harris hip score improved from 78.08 (47 to 96) to 95.36 points (88 to 100). The radiographic parameters all showed significant improvements. This study suggests that periacetabular osteotomy provides pain relief, improves acetabular cover and reduces the dynamic instability in patients with dysplastic hips

In this retrospective study we evaluated the proficiency of shelf autograft in the restoration of bone stock as part of primary total hip replacement (THR) for hip dysplasia, and in the results of revision arthroplasty after failure of the primary arthroplasty. Of 146 dysplastic hips treated by THR and a shelf graft, 43 were revised at an average of 156 months, 34 of which were suitable for this study (seven hips were excluded because of insufficient bone-stock data and two hips were excluded because allograft was used in the primary THR). The acetabular bone stock of the hips was assessed during revision surgery. The mean implant–bone contact was 58% (50% to 70%) at primary THR and 78% (40% to 100%) at the time of the revision, which was a significant improvement (p < 0.001). At primary THR all hips had had a segmental acetabular defect > 30%, whereas only five (15%) had significant segmental bone defects requiring structural support at the time of revision. In 15 hips (44%) no bone graft or metal augments were used during revision. . A total of 30 hips were eligible for the survival study. At a mean follow-up of 103 months (27 to 228), two aseptic and two septic failures had occurred. Kaplan-Meier survival analysis of the revision procedures demonstrated a ten-year survival rate of 93.3% (95% confidence interval (CI) 78 to 107) with clinical or radiological failure as the endpoint. The mean Oxford hip score was 38.7 (26 to 46) for non-revised cases at final follow-up. Our results indicate that the use of shelf autografts during THR for dysplastic hips restores bone stock, contributing to the favourable survival of the revision arthroplasty should the primary procedure fail. Cite this article: Bone Joint J 2013;95-B:777–81

There have been several studies examining the association between the morphological characteristics seen in acetabular dysplasia and the incidence of the osteoarthritis (OA). However, most studies focus mainly on acetabular morphological analysis, and few studies have scrutinised the effect of femoral morphology. In this study we enrolled 36 patients with bilateral acetabular dysplasia and early or mid-stage OA in one hip and no OA in the contralateral hip. CT scans were performed from the iliac crest to 2 cm inferior to the tibial tuberosity, and the morphological characteristics of both acetabulum and femur were studied. . In addition, 200 hips in 100 healthy volunteer Chinese adults formed a control group. The results showed that the dysplastic group with OA had a significantly larger femoral neck anteversion and a significantly shorter abductor lever arm than both the dysplastic group without OA and the controls. Femoral neck anteversion had a significant negative correlation with the length of the abductor lever arm and we conclude that it may contribute to the development of OA in dysplastic hips. Cite this article: Bone Joint J 2014; 96-B:1586–93

Introduction: Hip arthroplasty for dysplasia of the hip provides a challenge to all hip surgeons. The choice of prosthesis used depends on the severity of the deformity, and the challenge of acetabular reconstruction. We report a review of 105 of our cases operated since 1992 with a minimum two-year follow-up. Methods: The data in this study has been collected and entered prospectively since 1992 on an arthroplasty database. A total of 105 cases were identified and reviewed. The indication for surgery was painful hip osteoarthritis secondary to dysplasia. All patients were reconstructed with some attempt at restoration of the hip centre, and without femoral osteotomy. Results: There were 96 patients (10 bilateral), 66 females and 29 males whose mean age at surgery was 53 years (23 to 97 years). The mean follow-up period was 59 months (27 to 107 months). The hip was exposed via a posterior approach in 98% of cases. The majority (94%) of cases had no previous surgery. Depending on the degree of dysplasia either an ABG or S-ROM prosthesis was used. There were 78 Crowe I & II, and 18 Crowe III & IV hips. The more dysplastic hips required the versatility of the SROM stems to avoid excessive lengthening or femoral osteotomy. These cases also had significantly more inferior reconstruction of the hip centre, and medialisation of the hip centre. Complications occurred in 8/106 (8%) of cases, the mean time to occurrence being 25 months. The majority were dislocations 7 (7%). There were no sciatic nerve palsies. Revision was required for 5 cups and 1 stem. Clinical evaluation showed all patients were living at home and 85% had no activity restrictions. Mean Harris Hip Score was 92/100. None or mild thigh pain only was reported in 90% of cases. In 98% of cases patients were satisfied with their outcome. Radiographic evaluation showed stem ingrowth occurred in all cases. Minor osteolysis was apparent in 6% of cases. Spot welds were identified in 76% of cases. One case demonstrated pedestal formation. Conclusion: Reconstructing hip joint mechanics is a challenge in the dysplastic hip. The use of different prostheses for the varying severity in dysplasia has been an effective approach to optimise hip mechanics. Our results using this approach with cementless implants has given excellent short term clinical and radiographic results

Aims. Although periacetabular osteotomies are widely used for the treatment of symptomatic dysplastic hips, long-term surgical outcomes and patient-reported outcome measures (PROMs) are still unclear. Accordingly, we assessed hip survival and PROMs at 20 years after transpositional osteotomy of the acetabulum (TOA). Methods. A total of 172 hips in 159 patients who underwent TOA were followed up at a mean of 21.02 years (16.6 to 24.6) postoperatively. Kaplan-Meier analysis was used to assess survivorship with an endpoint of total hip arthroplasty (THA). PROMs included the visual analogue scale (VAS) Satisfaction, VAS Pain, Oxford Hip Score (OHS), and Forgotten Joint Score-12 (FJS-12). Thresholds for favourable outcomes for OHS (≥ 42) and FJS-12 (≥ 51) were obtained using the receiver operating characteristic curve with VAS Satisfaction ≥ 50 and VAS Pain < 20 as anchors. Results. THA was performed on 37 hips (21.5%) by the latest follow-up. Kaplan-Meier analysis indicated that the hip survival rate at 20 years was 79.7% (95% confidence interval (CI) 73.7 to 86.3). Multivariate analysis showed that preoperative Tönnis grade significantly influenced hip survival. Tönnis grades 0, 1, and 2 were associated with 20-year survival rates of 93.3% (95% CI 84.8 to 100), 86.7% (95% CI 79.8 to 94.3), and 54.8% (95% CI 41.5 to 72.3), respectively. More than 60% of the patients exhibited favourable PROMs. An advanced Tönnis grade at the latest follow-up and a higher BMI were both significantly associated with unfavourable OHS, but not with other PROMs. Conclusion. This study demonstrated the durability of TOA for hips with Tönnis grades 0 to 1 at 20 years. While the presence of advanced osteoarthritis and higher BMI was associated with lower hip functions (OHS), it was not necessarily associated with worse patient satisfaction and joint awareness. Cite this article: Bone Joint J 2022;104-B(7):767–774

We report the mid- to long-term (mean 20.3 years, 10 to 32.5) results of the Chiari pelvic osteotomy in patients with pre- to advanced stage osteoarthritis in dysplastic hips. We followed 163 Japanese patients (173 hips) with a mean age at surgery of 20 years (9 to 54). Overall, 124 hips (72%) had satisfactory results, with Harris hip scores ≥ 80. Satisfactory results were seen in 105 of 134 hips with pre- or early osteoarthritis (78%) and 19 of 39 hips with advanced osteoarthritis (49%). A total of 15 hips (9%) underwent a total hip replacement (THR) with a mean interval between osteotomy and THR of 16.4 years. With conversion to THR as the endpoint, the 30-year survival rate was 85.9% (95% confidence interval 82.3 to 89.5). It was 91.8% for patients with pre- or early osteoarthritis and 43.6% for those with advanced osteoarthritis (p < 0.001). We now perform the Chiari osteotomy for patients with dysplastic hips showing poor joint congruency and who prefer a joint-conserving procedure to THR

Direct anterior approach (DAA) is one of the best way to the hip joint for prevention of post-operative dislocation. We have applied this method as minimum invasive surgery (MIS) to more than two hundred developmental dysplastic hip of Japanese patients in total hip arthroplasty (THA) and there is no post-operative dislocation within three years of last observation carried forward (LOCF). The reason of this benefit is derived from the accuracy of cup positioning and keeping good muscle balance. But the learning curve is very important and some technical pitfalls are there in this approach. We have chosen thirty four patients that the duration of operating time more than one and half hours and loss of blood more than five hundred gram in hour series. The most important factors of the difficulties are the combinations of shortening of femoral neck, especially Perthes like deformity of developmental deformities of the hip joint (DDH) and widening of pelvic bone for the reason of insufficiency working spaces and the difficulties of broaching insertion (8/34). The second factor is the contracture of hip and knee joints combinations for the difficulties of lift up the proximal femur as broaching stem (3/34). The obesity, Body Mass Index (BMI) above thirty is not the reason of difficulties of women in our series. DAA can be extended to Smith-Petersen approach and very useful technique for primary THA in Japanese dysplastic hip patients

Aims

Although there are various pelvic osteotomies for acetabular dysplasia of the hip, shelf operations offer effective and minimally invasive osteotomy. Our study aimed to assess outcomes following modified Spitzy shelf acetabuloplasty.

In order to evaluate the relationship between acetabular and proximal femoral alignment in the initiation and evolution of osteoarthritis of the dysplastic hip, the acetabular and femoral angles were calculated geometrically from radiographs of 62 patients with pre-arthrosis and early osteoarthritis. The sum of the lateral opening angle of the acetabulum and the neck-shaft angle was defined as the lateral instability index (LII), and the sum of the anterior opening angle of the acetabulum and the anteversion angle of the femoral neck as the anterior instability index (AII). These two indices were compared in dysplastic and unaffected hips. A total of 22 unilateral hips with pre-arthrosis were followed for at least 15 years to determine whether the two indices were associated with the progression of osteoarthritis. The LII of the affected hips (197.4 (. sd. 6.0)) was significantly greater than that of the unaffected hips (1830 (. sd. 6.9)). A follow-up study of 22 hips with pre-arthrosis showed that only the LII was associated with progression of the disease, and an LII of 196 was the threshold value for this progression

Aims. The aim of this study was to compare patient-reported outcome measures (PROMs), radiological measurements, and total hip arthroplasty (THA)-free survival in patients who underwent periacetabular osteotomy (PAO) for mild, moderate, or severe developmental dysplasia of the hip. Patients and Methods. We performed a retrospective study involving 336 patients (420 hips) who underwent PAO by a single surgeon at an academic centre. After exclusions, 124 patients (149 hips) were included. The preoperative lateral centre-edge angle (LCEA) was used to classify the severity of dysplasia: 18° to 25° was considered mild (n = 20), 10° to 17° moderate (n = 66), and < 10° severe (n = 63). There was no difference in patient characteristics between the groups (all, p > 0.05). Pre- and postoperative radiological measurements were made. The National Institute of Health’s Patient Reported Outcomes Measurement Information System (PROMIS) outcome measures (physical function computerized adaptive test (PF CAT), Global Physical and Mental Health Scores) were collected. Failure was defined as conversion to THA or PF CAT scores < 40, and was assessed with Kaplan–Meier analysis. The mean follow-up was five years (2 to 10) ending in either failure or the latest contact with the patient. Results. There was no significant difference in PROMs for moderate (p = 0.167) or severe (p = 0.708) groups compared with the mild dysplasia group. The numerical pain scores were between 2 and 3 units in all groups at the final follow-up (all, p > 0.05). There was no significant difference (all, p > 0.05) in the proportion of patients achieving target correction for the LCEA between groups. The mean correction was 12° in the mild, 15° in the moderate (p = 0.135), and 23° in the severe group (p < 0.001). Failure-free survival at five years was 100% for mild, 79% for moderate, and 92% for severely dysplastic hips (p = 0.225). Conclusion. Although requiring less correction than hips with moderate or severe dysplasia, we found PAO for mild dysplasia to be associated with promising PROMs, consistent with that of the general United States population, and excellent survivorship at five years. Future studies should compare these results with the outcome after arthroscopy of the hip in patients with mild dysplasia. Cite this article: Bone Joint J 2019;101-B(6 Supple B):16–22

An eight-year-old girl who suffered a traumatic dislocation of a congenitally dysplastic hip is described. No other such case is recorded in the literature

BACKGROUND. There is no report of additional type of bulk bone grafting (Ad-BG) method with impaction morselized bone graft for reconstruction of shallow dysplastic hip in total hip arthroplasty. The purpose of this study was to define the shallow acetabulum and to evaluate the clinical and radiographic results of primary total hip arthroplasty (THA) with Ad-BG method. MATERIALS and METHODS. With modification of Crowe's classification, shallow dysplasia was defined and classified (Fig. 1). Between October 1999 and August 2008, 120 hips of 302 THAs for dysplastic hip were defined as shallow and Ad-BG was done in 96 hips (80% of shallow hips). For 24 hips with shallow dysplasia, THA were performed by using conventional type of interpositional bulk bone graft (Ip-BG) (8 hips) or without bone graft by using rigid lateral osteophyte. All patients were followed clinically using the Japanese Orthopaedic Association (JOA) score and also Merle d'Aubigne and Postel (M&P) scores in a prospective fashion, and radiographs were analyzed retrospectively. The criteria used for determining loosening were migration or total radiolucent zone between the prosthesis (or bone cement) and host bone. The mean follow-up periods were 8.0 ± 2.3 (5.0–13.5) years. Operative technique. Resected femoral head was sliced with thickness of 1–2 cm, and then a suitable size of the bulk bone block was placed on the lateral cortex of the ilium and fixed by polylactate absorbable screws. Autogenous impaction morselized bone grafting with or without hydroxyapatite granules was performed in conjunction with a cemented socket (Fig. 2). The same surgeon assisted by his colleagues operated all of the cases. RESULTS. No acetabular components were revised except for a case with shallow and Crowe type IV acetabulum. The mean JOA and M&P score for the hips improved from preoperative 39 and 6 points to postoperative 93 and 17 points respectively. Radiographically, the Ad-BGs in most of the cases were remodeled and recognized reorientation within 2 years postoperatively. CONCLUSIONS. The authors report good results of acetabular reconstruction with the use of Ad-BG technique in conjunction with impaction morselized bone graft for shallow dysplastic hip in primary THA. Osteointegration and good clinical outcome were achieved in most of cases. However longer term outcome should be the subject of further investigation

Background. BHA is popular surgery for femoral neck fractures expecially elderly patients. However, clinical results are variable that factors affecting results are questionable. Therefore we investigated radiologic fators, dysplastic hip whether influences results of BHA. Methods. Between 2004 and 2009, 200 patients undergoing bipolar hemiarthroplasty for femoral neck fracture were divided two groups; a lateral center edge (LCE) angle of < 16 degree or > 16 degree on anteroposterior radiographs. All surgical procedures were performed by a single surgeon. Dermogrpahic data, the harris hip score, WOMAC index, Koval activity level, and complication were recorded. The minimum follow up interval was 4 years (mean, 7.8 years). Result. Late postoperative complications such as periprosthetic joint infection, acetabular erosion, and subluxation of bioplar head were commonly observed in a group <16 degree of center edge angle. Clinical score was significantly lower in dysplastic group. Revision rate was higher in dysplastic group compared with group LCE angle of above the 16 degree. Conclusion. These results suggest that the dysplastic nature might be affected result of bipolar hemiarthroplasty in femroal neck fracture especially elderly patients

Aims

The aims of this study were to compare clinically relevant measurements of hip dysplasia on radiographs taken in the supine and standing position, and to compare Hip2Norm software and Picture Archiving and Communication System (PACS)-derived digital radiological measurements.

Introduction. Acetabular bone deficiency, especially proximal and lateral deficiency, is a difficult technical problem during primary total hip arthroplasty (THA) in developmental hip dysplasia (DDH). We report a configuration-based acetabular classification, a modification of the Crowe's classification, of DDH, including a definition of shallow acetabuli. We also report a new reconstruction method using a medial reduced cemented socket andadditional bulk bone in conjunction with impaction morselized bone grafting (Ad-BBG method). We aimed to evaluate usefulness of the classification and the method's clinical/radiographic outcomes. Methods. One hundred thirty one hips of 330 THAs for DDH (40%) were defined shallow. The Ad-BBG methodwas performed on 102 hips (78% shallow hips). For the 24 remaining hips, THA was performed using the conventional interposition bulk bone grafting (Ip-BBG) (8 hips)or without bone grafting by using rigid lateral osteophyte (16 hips). Japanese Orthopaedic Association (JOA) scores and the Merle d'Aubigne and Postel (M&P) scores were used in follow-up; radiographs were analyzed retrospectively. The criteria used for determining loosening were migration or a total radiolucent zone between the prosthesis/bone cement and host bone. The follow-up period was 9.2 ± 2.6 (range, 5.0–14.0) years. Operative Technique. Theresected femoral head was sectioned at 1–2-cm thickness, and a suitable size of the bulk bone graft was placed on the lateral iliac cortex and fixed by polylactate absorbable screws. Autogenous impaction morselized bone grafting, with or without hydroxyapatite granules, was performed along with the implantation of medial reduced cemented prosthetic hip socket. The same surgical team performed all surgical procedures. Results. Acetabular component was revised in only one case with a shallow and Crowe Type IV acetabulum. The mean JOA and M&P scores improved from preoperative 39.3 and 6.8 points to postoperative 93.9 and 17.2 points, respectively. Within 2 years postoperatively, most Ad-BBGs cases showed successful bone remodeling and bone graft reorientation on radiographs. Conclusions. We had good results of acetabular reconstruction in primary THA using the medial reduced cemented socket and bone grafting methods including the Ad-BBG technique in conjunction with impaction morselized bone grafting for shallow dysplastic hip. Osteointegration and good clinical outcomes were achieved in most cases. However, long-term outcomes should be subject of further investigation. Summary. Reconstruction methods for shallow dysplastic hip using medial reduced cemented socket and additional bulk bone grafting in conjunction with impaction morselized bone grafting are presented

Background and Aims: Concentric pressure of the femoral head on acetabulum is the necessary prerequisite for normal hip development. In the case of diminished hip joint area an elevation of hip joint pressure ensues. If this pressure elevation lasts for a long period of time early degenerative changes are proposed to occur. The aim of our study is to substantiate the connection between hip joint pressure and occurrence of hip osteoarthritis in dysplastic hips. Methods: From 1955 to 1965 112 patients were treated non-operatively for hip dysplasia in developmental dysplasia of the hip in Dept. of Orthopaedic Surgery, Ljubljana. Using mathematical model of the hip, peak joint stress was measured in 27 patients, which met the enrolment criteria consisting of: a.) initial rentgenograph taken at least 20 years ago, b.) closed triradiate cartilage and no rentgenographic signs of osteoarthritis at the time of initial radiograph, c.) no neurological deþcit of lower limbs and no operative procedure during follow up period. All hips were re-examined clinically in year 2000. Results: Mean age at the latest follow up was 47 years (35 years to 61 years). Mean time interval between the rentgenograph from which the hip joint stress was measured and clinical examination was 27 years (20 years to 33 years). Signiþcant correlation was found between peak hip joint stress and Harris hip score (p 0.0013). Discussion and conclusions: Our results indicate that occurrence osteoarthritis of the hip could be related to the degree of hip dysplasia at the end of skeletal growth. The correlation between peak hip joint stress and Harris hip score was one order of magnitude larger than the corresponding correlation between CE angle and Harris hip score, which indicates that hip joint stress represents a valuable parameter describing the status of the hip joint