Acetabular Fossa Research Articles

Hip preservation surgery and the acetabular fossa.

As our understanding of hip function and disease improves, it is evident that the acetabular fossa has received little attention, despite it comprising over half of the acetabulum’s surface area and showing the first signs of degeneration. The fossa’s function is expected to be more than augmenting static stability with the ligamentum teres and being a templating landmark in arthroplasty. Indeed, the fossa, which is almost mature at 16 weeks of intrauterine development, plays a key role in hip development, enabling its nutrition through vascularization and synovial fluid, as well as the influx of chondrogenic stem/progenitor cells that build articular cartilage. The pulvinar, a fibrofatty tissue in the fossa, has the same developmental origin as the synovium and articular cartilage and is a biologically active area. Its unique anatomy allows for homogeneous distribution of the axial loads into the joint. It is composed of intra-articular adipose tissue (IAAT), which has adipocytes, fibroblasts, leucocytes, and abundant mast cells, which participate in the inflammatory cascade after an insult to the joint. Hence, the fossa and pulvinar should be considered in decision-making and surgical outcomes in hip preservation surgery, not only for their size, shape, and extent, but also for their biological capacity as a source of cytokines, immune cells, and chondrogenic stem cells.Cite this article: Bone Joint Res 2020;9(12):857–869.

Podocytic infolding in Schimke immuno-osseous dysplasia with novel SMARCAL1 mutations: a case report

BackgroundSchimke immuno-osseous dysplasia (SIOD) is a rare autosomal recessive disorder characterized by spondyloepiphyseal dysplasia, progressive renal insufficiency and defective cellular immunity. Podocytic infolding glomerulopathy (PIG) is a newly proposed disease entity characterized by microspheres or microtubular structures associated with podocytes infolding into the glomerular basement membrane (GBM) on electron microscopy (EM).Case presentationA 4-year-old boy was admitted to our ward due to proteinuria and edema lasting 1 month. He had a short trunk and demonstrated subtle dysmorphology, with a triangular shape, a broad nasal bridge and a bulbous nasal tip. The laboratory findings were as follows: lymphocytes, 0.5 × 109/L; urine protein, 3.67 g/d; albumin, 9.8 g/L; and cholesterol, 11.72 mmol/L. Skeletal X rays showed small iliac wings, small ossification centers of the capital femoral epiphyses, shallow dysplastic acetabular fossae and mildly flattened vertebrae. The specimen for light microscopy (LM) suggested focal segmental glomerulosclerosis (FSGS). EM revealed a focal thickness of the GBM with some cytoplasmic processes of podocyte infolding into the GBM. Gene sequencing showed novel compound heterozygous mutations in the SMARCAL1 gene (c.2141 + 5G > A; c.2528 + 1G > A) that were inherited from his parents. Finally, we established the diagnosis of SIOD and treated him with diuretics and angiotensin-converting enzyme inhibitors (ACEIs).ConclusionThe pathogenic mechanism of PIG has not been clarified. Further studies are required to understand whether gene mutations, especially those related to podocytes, contribute to the pathogenesis of podocytic infolding.

Comparing the Accuracy of Morphometric and Morphological Criteria of Hip Bone in Gender Determination

Background: A primary aim of forensic medicine is gender determination. Although hip is the optimal bone for this purpose, different determining criteria of this bone do not have the same accuracy. This is important in conditions that only parts of hip remain to determine gender. This study aimed to evaluate the accuracy of different hip criteria in gender determination. Methods: This cross-sectional study evaluated a total of 160 paired hips (80 males and 80 females) removed from the bodies for bone transplantation. Morphometric criteria were vertical and horizontal acetabular diameters and superior and inferior pubic ramus widths. Morphological criteria were a greater sciatic notch, obturator foramen, pubic body, preauricular sulcus, acetabular fossa position, and ischial tuberosity. The obtained data were analyzed using Cross Tab, t-test, and logistic regression analysis by SPSS. The significance level was set at P 0.05). In gender determination, acetabular diameter and greater sciatic notch had the highest accuracy (85%), and obturator foramen (67.5%) and superior and inferior pubic ramus widths (65%) had the lowest accuracy. Conclusion: Hip bone is not always completely available and preserved to determine gender. Moreover, sometimes not all anthropometric criteria of the bone are in favor of one gender. Therefore, investigating the accuracy of different criteria can be very important in interpreting the results. Thus, it has always been emphasized on the use of all available information in gender determination.

Application of soft tissue loosening and acetabular reconstruction in hip replacement for patients with severe femoral head necrosis

To explore the effect of application of soft tissue loosening and acetabular reconstruction in hip replacement for patients with severe femoral head necrosis on joint function. Methods: From June 2012 to August 2016, 68 patients with severe femoral head necrosis (Ficat III, IV) underwent total hip replacement with soft tissue release and acetabular reconstruction at the Second Xiangya Hospital of Central South University. Total hip replacement is performed by the posterolateral approach. The acetabulum was rebuilt and the length of the affected limb was prolonged after clearing the scar tissue, proliferating the epiphysis, releasing the abductor muscle group and the adductor muscle group, dissecting the soft tissue around the acetabulum. One year after surgery, Harris score, X-ray positive lateral radiograph for the affected side and full-length X-ray examination for both lower extremities were performed to evaluate the curative effect. Results: The postoperative follow-up time ranged from 1.0 to 5.5 years. All patients' femoral heads returned to normal anatomical position and the affected limb length was restored to 1.5-3.5 cm; all patients did not damage the sciatic nerve. The Harris scores for 68 patients increased from 38.6±7.5 to 78.2±5.7 (P=0.029) in the first year after surgery. Conclusion: During hip replacement surgery for severe femoral head necrosis, soft tissue dissection and acetabular reconstruction can be used to ensure anatomical reconstruction for the acetabular fossa and to improve abductor function.

Modified lateralized head sign: An accurate marker in diagnosing adult hip dysplasia

BackgroundAlthough lateralized head sign (LHS) is considered indicative of structural instability, it lacks reproducibility, and its usefulness in diagnosing adult hip dysplasia is unknown. In this study, we proposed a modified LHS and aimed to determine its reliability and accuracy in diagnosing adult hip dysplasia. MethodsWe reviewed anteroposterior pelvic radiographs of 94 patients (134 hips) with hip dysplasia. As controls, 133 normal hips were evaluated. We defined the modified lateralization distance (LD) as the horizontal distance between the medial aspect of the femoral head to the acetabular fossa. The sensitivity, specificity, and cutoff value of modified LD in diagnosing hip dysplasia were calculated using receiver operating characteristic curve analysis. ResultsThe sensitivity and specificity of the modified LD (79% and 87%, respectively) were higher than those of the conventional LD (63% and 80%, respectively). Diagnostic accuracy was further improved when patients were divided on the basis of sex. The sensitivity and specificity of the modified LD in men were 89% and 97%, respectively, with a cutoff value of 12 mm, while in women, they were 80% and 96%, respectively, with a cutoff value of 9.7 mm. Therefore, we defined the modified LHS as presentation with a modified LD ≥ 12 mm in men and ≥10 mm in women. Between three observers, the kappa value for intraobserver reliability was ≥0.9, while that for interobserver reliability was >0.8. The mean sensitivity and specificity of the modified LHS in diagnosing hip dysplasia were 85% and 99%, respectively. ConclusionsModified LHS—a horizontal distance between the medial aspect of the femoral head and the acetabular fossa ≥12 mm in men and ≥10 mm in women—is a clinically useful marker in detecting lateral femoral head subluxation indicative of hip dysplasia or structural hip instability.

Application of the recent SanMillán-Rissech acetabular adult aging method in a North American sample.

Recently, a renewed acetabular aging methodology was published by San-Millán et al. (Int J Leg Medicine, 47, 131: 501-525), refining the variables associated with acetabular fossa aging in different populations. Due to its novelty, this method has not yet been examined in any other population, other than it was developed and originally tested on. Therefore, the main goals of this study are two-fold: (1) to evaluate the accuracy of SanMillán-Rissech's method in a North American sample made up of 826 white (456 males and 370 females) individuals from the Bass Collection and (2) to determine whether the revised methodology shows higher rates of accuracy than the original methodology (J Forensic Sci, 31, 51(2): 213-229). Scores obtained by both methodologies were analyzed via a Bayesian statistical program (IDADE2) that estimates a relative likelihood distribution for the target individuals, produces age-at-death estimates, and provides 95% confidence intervals. Even though the revised method was developed using a Western European collection, the results demonstrate that it is also applicable to North American samples with reasonable accuracy results, i.e., an average absolute error of 7.19years in males and 9.65years in females. However, accuracy in females is significantly lower than in males, likely due to their higher morphological variability associated with different factors other than age. The significantly better performance of the revised methodology compared with the original is also been confirmed by the current findings from this North American sample, supporting the renewed system as a better aging methodology. Although work on further populations is needed, previously and current results should encourage professionals to include the acetabular method in forensic and archaeological laboratories routines.

Clinical and radiological findings in Brazilian patients with mucolipidosis types II/III.

The present study aims to provide orientation for clinicians and radiologists to recognize the most prevalent findings leading to diagnosis in mucolipidosis from a description of the natural history of five Brazilian cases. We conducted an observational and retrospective study of five patients with clinical and radiological diagnosis of mucolipidosis. Clinical evaluation consisted of information obtained from records and including physical, neurologic, and dysmorphic evaluations. Radiologic studies consisted of complete skeletal radiographs of all patients. Enzyme assessment was performed for confirmation of the diagnosis. The five patients were referred for genetic evaluation due to disproportionate short stature with short trunk accompanied by waddling gait. Age at referral varied from 11months to 28years. The most prevalent findings were joint restriction (4/5 patients), neuropsychomotor developmental delay (3/5), coarse facies (2/5), hypertrophic cardiomyopathy (2/5), and mental retardation (1/4 patients). The most common radiological findings were anterior beaking of the vertebral bodies (5/5), shallow acetabular fossae (5/5), epiphyseal dysplasia (5/5), platyspondyly (4/5), pelvic dysplasia (4/5), decreased bone mineralization (4/5), scoliosis (3/5), wide and oar-shaped ribs (3/5), generalized epiphyseal ossification delay (3/5), and hypoplasia of basilar portions of ilea (3/5). Enzyme assessment showed α-iduronidase, α-mannosidase, β-glucuronidase, hexosaminidase A, and total hexosaminidase increased in plasma and normal glycosaminoglycans concentration. One patient was clinically classified as ML II and four patients as ML III. The follow-up of five patients showed the typical clinical and radiological findings allowing the diagnosis, thus improving clinical management and providing adequate genetic counseling. Clinicians and radiologists can take advantage of the information from this work, enhancing their differential diagnosis ability.

The association between skeletal lesions and tuberculosis diagnosis using a probabilistic approach

Sensitivity and specificity estimates for 18 skeletal lesions were generated from modern skeletons for future paleoepidemiological analyses of tuberculosis prevalence in archaeological samples. A case-control study was conducted using 480 skeletons from 20th century American skeletal collections. One-half of the skeletons were documented tuberculosis cases (Terry Collection). The remaining age and sex-matched skeletons were controls (Bass Collection). The association between 18 candidate skeletal lesions and tuberculosis was established by comparing lesion distributions in case and control groups. Lesion indicators at six locations – visceral surface of ribs, ventral vertebral bodies, lateral part of ilium, acetabular fossa, iliac auricular surface, and ulna olecranon process - occurred significantly more often among cases than in controls, and were associated with one another. The most useful indicator proved to be a bony reaction on ventral thoracic and lumbar vertebral bodies. Its presence means a 53.3% probability of a true tuberculosis diagnosis. Because of the nature of the reference sample – 20th century American cases – sensitivity and specificity estimates will better estimate disease prevalence in archaeological samples from cultural settings where pulmonary tuberculosis predominated. The general approach of this proof-of-concept study is applicable to other diseases that occur commonly and affect bone.

Posterior Bony Impingement—Potential Mechanism of Ligamentum Teres Tears

To describe a potential causal mechanism of ligamentum teres (LT) tears, a specific treatment for posterior impingement of the LT, and to report the minimum 2-year outcome of this treatment. We retrospectively reviewed data collected from 1,251 hip arthroscopies performed by the senior surgeon over a 26-month period. During this time, 424 LT tears were identified including 9 patients with isolated partial LT tears caused by impingement of the LT against a prominent acetabular fossa posterior wall and no other intra-articular pathology. All 9 patients were treated with LT tear debridement and excision of the impinging bony prominence using an arthroscopic burr. Patients were followed with a modified Harris hip score and nonarthritic hip score for a minimum of 24months (mean, 29months; range, 24-38months). After surgery, all patients returned to their preinjury level of activity. The modified Harris hip score increased from a mean of 58.9 preoperatively (range, 41.8-84.7) to 89.2 (range, 70.3.5-96.7) (P= .02) at a minimum of 2-year follow-up. Similarly, the nonarthritic hip score increased from a mean of 56.2 (range, 35-90) to 91.9 (range, 81.5-98.5) (P= .01) at a minimum of 2years after surgery. There were no complications associated with the procedure and no revision surgeries performed over the 2-year follow-up. LT tears may, very uncommonly, be caused by impingement of the mid-part of the ligament against a prominent posterior acetabular fossa edge. In this group of 9 cases, debridement of the torn ligament segment, in combination with resection of the impinging bone, was associated with marked symptomatic improvement and full return to activities for a minimum of 2years. Level IV, therapeutic case series.

The Acetabular Fossa May Not Be Located at the True Center of the Acetabulum: A Detailed Analysis Using Preoperative CT Images.

The acetabular fossa is thought to be located in the center of the acetabulum, and acetabular reaming in total hip arthroplasty is conventionally performed in the center of the fossa. However, the actual location of the fossa and the influence that hypoplasia or deformity may have on the position of the fossa are unknown. We hypothesized that the fossa is located in the center of the acetabulum, regardless of hypoplasia or deformity. Fifty patients with normal hips (normal hip group), 50 patients with dysplasia who underwent rotational acetabular osteotomy (dysplastic hip group), and 46 patients with osteoarthritis who underwent total hip arthroplasty (osteoarthritic hip group) were evaluated by computed tomography (CT) imaging. On the horizontal plane that passes through the center of the femoral head, the center line of the acetabulum was defined as the perpendicular bisector of the anterior and posterior rims of the acetabulum. The angle and distance of the center of the acetabular fossa in relation to the center line of the acetabulum were evaluated; furthermore, the center position of the fossa from the anterior margin of the acetabulum was calculated as a ratio relative to acetabular size. A 1-way analysis of variance was performed to compare measurements among the 3 groups. The center of the acetabular fossa was positioned anteriorly to the center line of the acetabulum in all 3 groups. The mean center angle of the acetabular fossa was 14.0° ± 3.8°, 15.2° ± 5.6°, and 14.9° ± 5.5° in the normal, dysplastic, and osteoarthritic hip groups, respectively (p = 0.33). The mean center distance of the acetabular fossa was 5.6 ± 1.8, 5.8 ± 2.3, and 6.1 ± 2.2 mm, respectively (p = 0.55). The mean center position of the acetabular fossa was 38.8% ± 3.3%, 38.5% ± 4.2%, and 38.3% ± 3.9%, respectively (p = 0.71). The center of the acetabular fossa is positioned anteriorly to the center of the acetabulum, and the positioning is affected by neither dysplasia nor osteoarthritis. The preconception that the center of the acetabulum corresponds to the center of the acetabular fossa may risk eccentric reaming, possibly damaging the anterior wall. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Does Capsular Laxity Lead to Microinstability of the Native Hip?

Background: Hip “microinstability” is commonly cited as the cause of symptoms that occur in the presence of translation of the femoral head away from conformity with the acetabular fossa. However, there is still no consistent objective criteria defining its presence and biomechanical basis. One hypothesis is that abnormal motion of the articular surfaces occurs because of capsular laxity, ultimately leading to clinical symptoms. Purpose: To determine the relationship between capsular laxity and abnormal rotation and translation of the hip. Study Design: Controlled laboratory study. Methods: Eight cadaveric hips were dissected down to the capsule and mounted in a customized multiaxial hip activity simulator. Each specimen was loaded with 5 N·m of internal and external rotational torque in full extension and 0°, 30°, 60°, and 90° of flexion. During testing, the relative position and rotation of the femur and the pelvis were monitored in real time with a 6-camera motion analysis system. The testing was repeated after capsular laxity was generated by placing a regular array of incisions (“pie crusting”) in the iliofemoral, pubofemoral, and ischiofemoral ligaments. Joint rotation and femoral head translation were calculated with specimen-specific models. A hip microinstability index was defined as the ratio between the length of the locus of the femoral head center and the radius of the femoral head during rotation from extension to 90° of flexion. Results: In intact hips, the components of femoral head translation were within 0.5 mm in positions close to neutral (<30° of flexion). Capsular modification led to significant increases in internal and external rotation (P < .01) and in the translation of the femoral head center at different positions (P < .05). Compared with intact hips, the femoral head was inferiorly displaced during external rotation and anteroinferiorly during internal rotation. The length of the locus of the femoral head center increased from 3.61 ± 1.30 mm to 5.35 ± 1.83 mm for external rotation (P < .05) and from 6.24 ± 1.48 mm to 8.21 ± 1.42 mm for internal rotation (P < .01). The correlations between rotational laxity and the total translation of the femoral head were not significant, with coefficients of 0.093 and 0.006 in external and internal rotation, respectively. In addition, the hip microinstability index increased from 0.40 ± 0.08 for intact hips to 0.55 ± 0.09 for modified hips (P < .01). Conclusion: The native hip approximates a concentric ball-and-socket joint within 30° of flexion; however, beyond 30° of flexion, the femoral head translation reached as high as 4 mm. Capsular laxity leads to microinstability of the hip, as indicated by significantly increased joint rotations and femoral head translations and an abnormal movement path of the femoral head center. However, there was no correlation between rotational laxity and the increase in femoral head translation. Clinical Relevance: Capsular laxity alters normal kinematics (joint rotation and femoral head translation) of the hip, potentially leading to abnormal femoral-acetabular contact and joint degeneration.

A new species of Anteophthalmosuchus (Crocodylomorpha, Goniopholididae) from the Lower Cretaceous of the Isle of Wight, United Kingdom, and a review of the genus

A new species of goniopholidid crocodyliform, Anteophthalmosuchus epikrator sp. nov., is herein described based on two specimens from the Wessex Formation of the Isle of Wight, UK. These specimens were previously referred to the type species Anteophthalmosuchus hooleyi. In addition, we provide a comprehensive redescription of the A. hooleyi holotype. The new species has several skull table and iliac morphological characteristics that distinguish it from A. hooleyi, such as: sub-square supratemporal fossae; thicker iliac crest that is not positioned low at the anterior iliac margin; absence of a bulge formed by the anterior convergence of the iliac and supraacetabular crests; a ‘wasp-waisted’ postacetabular process; and, a comparatively deeper acetabular fossa. The evolutionary relationships of A. epikrator were assessed in phylogenetic analyses that affirmed its status as a distinct species that is closely related to A. hooleyi. An additional Anteophthalmosuchus specimen from Belgium, the so called ‘Dollo's goniopholidid’, recently assigned to A. hooleyi is here referred to A. epikrator, based on the shared autapomorphies, and moreover, the results from the phylogenetic analyses which confirm the ‘Dollo's goniopholidid’ close affinity with the new species. Intriguingly, two of our cladistic analyses yielded a paraphyletic Anteophthalmosuchus in regards to the Spanish Anteophthalmosuchus species, A. escuchae, which was recovered forming a trichotomy with Hulkeopholis spp. The exclusion of A. escuchae from the cladistic analysis not only restored the monophyletic status of Anteophthalmosuchus, but also resolved previously found unsettled relationships within Goniopholididae. The most likely reason for this puzzling phylogenetic outcome is the relatively fragmentary nature of the Spanish Anteophthalmosuchus specimens, therefore, necessitating further study of new material in order to help elucidate its taxonomic relationships.

Arthroscopic Reconstruction of the Ligamentum Teres: A Guide to Safe Tunnel Placement

To provide a quantitative guide to tunnel placement concurrently through the femur and acetabulum during a ligamentum teres reconstruction, minimizing the risk of injury to the obturator neurovascular bundle. Nine human cadaveric pelvises, complete with femurs (mean age, 59.6years; age range, 47-65years), were studied. Before dissection, a 3-dimensional coordinate-measuring device was used to record the neutral orientation of the femur in the acetabulum. The specimens were then dissected free of all extra-articular soft tissue, except for the ligamentum teres and the obturator neurovascular bundle, and digitized. An anatomic femoral reconstruction tunnel through the femoral neck was simulated and extended along its axis into the acetabulum. The femur was digitally rotated internally from 0° to 30° and externally from 0° to 40°, as well as abducted from 0° to 30° and adducted from 0° to 20°, in increments of 1°. At each position, the location of the simulated acetabular reconstruction tunnel was measured with respect to the obturator bundle and the edge of the acetabular fossa. The anatomic reconstruction tunnel entered the lateral side of the femur at a mean distance of 7.0mm distal and 5.8mm anterior to the center of the vastus ridge. By angling the femur at 15° of internal rotation and 15° of abduction, the obturator neurovascular bundle was avoided in 100% of specimens. The most important finding of this study was that a ligamentum teres reconstruction tunnel could be reamed through the femoral neck and safely positioned in the acetabulum by angling the femur at 15° of internal rotation and 15° of abduction. These quantitative descriptions of the ligamentum teres reconstruction tunnels can be used to guide arthroscopic surgical interventions designed to address ligamentum teres pathology.

Minimally invasive technique for coxofemoral luxation stabilisation using transarticular toggle system: a cadaveric study.

To present a novel, semi-closed, surgical technique for coxofemoral luxation stabilisation using a transarticular toggle rod. Cadaveric study. Craniodorsal luxation was generated by transecting the ligamentum teres in 12 coxofemoral joints and was then reduced using a closed technique. Anteversion and inclination angles were measured using fluoroscopic projections. An arthroscope was inserted through a bone tunnel drilled from the third trochanter through the femoral neck. Following retraction of the arthroscope, a hole was drilled through the acetabular fossa via the femoral bone tunnel. A standard Arthrex® TightRope toggle button was pushed through the femoral bone tunnel into the acetabular fossa hole and tied over the oval metallic button above the third trochanter site. The exit point of the drill hole over the femoral head and that in the acetabular fossa were evaluated by surgical exposure of the coxofemoral articular surfaces. The TightRope entrance point into the acetabular fossa was accurate in all joints, with a mean distance from the acetabular fossa centre of 0·06 ±0·1 mm. The measured distance of the TightRope exit point from the femoral head to the fovea capitis was 2·04 ±1·7 mm. Femoral head cartilage damage was detected in nine of 12 joints. Closed reduction and stabilisation of coxofemoral luxations can be achieved using this minimally invasive technique. Refinements to the technique may be needed for its application in clinical cases due to relative high incidence of femoral head cartilage damage.

Observations of the Acetabulum and Proximal Femur of the Dire Wolf (Canis dirus, Leidy 1854)

individuals, including 23 ace- tabula and 23 proximal femora. The specimens are curated at the Page Museum, Rancho La Brea, CA USA. We selected specimens for the appearance of subtle pathology because our observation plan was lim- ited to establishing whether features of coxofemoral degenerative joint disease (DJD) would be observed on the acetabular fossa, medial articular margin, articular bone surface, lateral articular margin, and peri-articular structure. Similarly, evaluation of femora included articular surface and margin, peri-articular structure, and joint capsule attachment.

Shape variability of the adult human acetabulum and acetabular fossa related to sex and age by geometric morphometrics. Implications for adult age estimation

This study aims to explore shape variability of the acetabulum during the human adult life span, in relation to sex and age. The human acetabular shape was analysed in 682 os coxae from three different documented skeletal collections from the Iberian Peninsula. Two landmarks and thirty-two sliding semi-landmarks were used for the geometric morphometric procedures and a clock-wise standard was used for orientation. The 180° meridian (6:00) line was positioned over the midpoint of the acetabular notch and 36 reference points in 10° increments along the rim were marked. Data showed that size, sex and age significantly influence acetabular shape variation. Sex differences were significant in individuals younger than 65 years old and were characterised by males exhibiting relatively extended acetabular rim profiles from 10:00 to 1:00, narrower acetabular notches, and reduced acetabular fossae. In addition, three main age-related changes occurred to the acetabular shape in both sexes: outer acetabular profile modification, with extension from 10:00 to 1:00 and reduction from 7:00 to 9:00, acetabular notch narrowing, and acetabular fossa reduction. The age-related changes that were observed are shared by both sexes and seem to be related to bone production associated with age. Specifically, age appears to affect the entire border of the lunate surface: the acetabular rim, both acetabular horns, and the outer edge of the acetabular fossa. Furthermore, shape data confirmed the clover-leaf shape of the acetabular fossa in both males and females. These results improve our understanding of acetabular shape, and assist in refining age-estimation methods and enhancing hip surgery and rehabilitation.

Is Increased Acetabular Cartilage or Fossa Size Associated With Pincer Femoroacetabular Impingement?

Surgical treatment for pincer femoroacetabular impingement (FAI) of the hip remains controversial, between trimming the prominent acetabular rim and reverse periacetabular osteotomy (PAO) that reorients the acetabulum. However, rim trimming may decrease articular surface size to a critical threshold where increased joint contact forces lead to joint degeneration. Therefore, knowledge of how much acetabular articular cartilage is available for resection is important when evaluating between the two surgical options. In addition, it remains unclear whether the acetabulum rim in pincer FAI is a prominent rim because of increased cartilage size or increased fossa size. We used reformatted MR and CT data to establish linear length dimensions of the lunate cartilage and cotyloid fossa in normal, dysplastic, and deep acetabula. We reviewed the last 200 hips undergoing PAO, reverse PAO, and surgical dislocation for acetabular rim trimming at one institution. We compared MR images of symptomatic hips with acetabular dysplasia (20 hips), pincer FAI (29 hips), and CT scans of asymptomatic hips from patients who underwent CT scans for reasons other than hip pain (20 hips). These hips were chosen sequentially from the underlying pool of 200 potential subjects to identify the first 10 male and the first 10 female hips in each group that met inclusion criteria. As a result of low numbers, we included all hips that had undergone reverse PAO and met inclusion criteria. Cartilage width was measured medially from the cotyloid fossa to the lateral labrochondral junction. Cotyloid fossa linear height was measured from superior to inferior and cotyloid fossa width was measured from anterior to posterior. Superior lunate cartilage width (SLCW) and cotyloid fossa height (CFH) were measured on MR and CT oblique coronal reformats; anterior lunate cartilage width (ALCW), posterior lunate cartilage width (PLCW), and cotyloid fossa width (CFW) were measured on MR and CT oblique axial reformats. Cohorts were compared using multivariate analysis of variance with Bonferroni's adjustment for multiple comparisons. Compared with control acetabula, dysplastic acetabula had smaller SLCW (2.08 ± 0.29 mm versus 2.63 ± 0.42 mm, mean difference = -0.55 mm; 95% confidence interval [CI] = -0.83 to -0.27; p < 0.01), ALCW (1.20 ± 0.34 mm versus 1.64 ± 0.21 mm, mean difference = -0.44 mm; 95% CI = -0.70 to -0.18; p = 0.00), CFH (2.84 ± 0.37 mm versus 3.42 ± 0.57 mm, mean difference = -0.59 mm; 95% CI = -0.96 to -0.21; p < 0.01), and CFW (1.98 ± 0.50 mm versus 2.77 ± 0.33 mm, mean difference = -0.80 mm; 95% CI = -1.16 to -0.42; p < 0.0001). Based on the results, we identified two subtypes of deep acetabula. Compared with controls, deep subtype 1 had normal CFH and CFW but increased ALCW (2.09 ± 0.42 mm versus 1.64 ± 0.21 mm; p < 0.001) and PLCW (2.32 ± 0.36 mm versus 2.00 ± 0.32 mm; p = 0.04). Compared with controls, deep subtype 2 had increased CFH (4.37 ± 0.51 mm versus 3.42 ± 0.57 mm; p < 0.01) and CFW (2.76 ± 0.54 mm versus 2.77 ± 0.33 mm; p = 1.0) but smaller SCLW (2.12 ± 0.40 mm versus 2.63 ± 0.42 mm; p < 0.01). Deep acetabula have two distinct morphologies: subtype 1 with increased anterior and posterior cartilage lengths and subtype 2 with a larger fossa in height and width and smaller superior cartilage length. In patients with deep subtype 1 hips that have increased anterior and posterior cartilage widths, rim trimming to create an articular surface of normal size may be reasonable. However, for patients with deep subtype 2 hips that have large fossas but do not have increased cartilage widths, we propose that a reverse PAO that reorients yet preserves the size of the articular surface may be more promising. However, these theories will need to be validated in well-controlled clinical studies.

Surgical Dislocation of the Hip in the Treatment of Complex Osteochondral Injury to the Femoral Head.

The optimal treatment for osteochondral fracture of the femoral head associated with posterior dislocation remains unclear. A case can be made to treat small fragments and those that concentrically reduce nonoperatively. On the other end of the spectrum are those where significant size and residual displacement warrant consideration of operative fixation. This video demonstrates the treatment of a large complex multifragmentary osteochondral femoral head fracture with surgical dislocation. With the patient in lateral decubitus position, the trochanter is approached through lateral incision. The trochanter is cut and capsulotomy performed taking care to preserve the critical medial femoral circumflex artery. Fixation with headless screws is performed from the small comminuted fragments into the dominant section of intact femoral head. Experience suggests that anatomic fixation through surgical dislocation can be carried out with low incidence of subsequent avascular necrosis and degenerative articular change. Given the degree of local osseous and muscular trauma, consideration should be given to prophylaxis of heterotopic bone. Although small osteochondral fragments restricted to the acetabular fossa can be treated nonoperatively, the size and displacement of the presented fragment mandated operative reduction. Given the predicted complexity of repair, the surgical dislocation approach was chosen to provide maximum exposure optimizing the chances for successful fixation.

New approach to age estimation of male and female adult skeletons based on the morphological characteristics of the acetabulum.

Age estimation is essential to the human identification process, both in forensic and archeological contexts. Based on the previous male-specific method of Rissech et al. (J Forensic Sci, 2006, 51:213-229), a new approach to age estimation based on the acetabulum has been described and evaluated in 611 individuals from the Lisbon Collection (Lisbon, Portugal). This paper has two main goals: (1) to revise and better define the variables of Rissech's method related to the acetabular fossa, namely, variables 5, 6, and 7, and (2) to extend the applicability of this new approach to both sexes while analyzing age-related sex differences in the acetabular aging process. The results demonstrate the suitability of combining acetabulum traits and a Bayesian approach to estimating age in adults of both sexes. This study has confirmed the usefulness of the redefined variables of the acetabular fossa when age-related changes are considered. Furthermore, the newly defined variables have good to excellent values of repeatability. The study has also extended the method's applicability to females. The revised method has absolute error averages of 7.28years for males and 7.09years for females, based on a sex-specific reference sample. In addition, approximately 74% of the individuals estimated had an absolute error less than 10years. Interestingly, the acetabular aging process follows similar trends in both sexes, but the aging rate seems to be different between males and females, especially in middle-aged individuals. Despite the fact that the age estimates, on average, did not improve significantly with the use of a sex-specific reference sample, it is recommended that the sexes be analyzed separately due to the differences in aging rates and inaccuracy values.

Hip Arthroscopy: Where We Are, and Where We Are Going.

Hip Arthroscopy: Where We Are, and Where We Are Going.