Teardrop Figure Research Articles

Smith c/b ratio and teardrop figure measurements; Can it be used in the follow-up of patients who underwent salter innominate osteotomy?

This study aimed to investigate the effectiveness of radiological parameters used in the follow-up of patients who underwent salter innominate osteotomy (SIO) for the treatment of developmental dysplasia of the hip. Acetabular index, c/b ratio, teardrop width, femoral head teardrop distance (TDD), and acetabular teardrop angle were measured on anteroposterior pelvic radiographs of patients who underwent SIO between 2017 and 2020. The patients were divided into 2 groups according to their preoperative Tönnis stage. Twenty-five (51%) hips of 23 patients with Tönnis stage 2 were classified into group 1, and 24 (49%) of 17 patients with Tönnis stages 3 and 4 were classified into group 2. Changes in radiologic parameters over time and between the groups were statistically evaluated. The study included 49 hips of 40 patients (37 female and 3 male). The age at surgery was 26.53 (18-53) months. After a mean follow-up period of 33.7 ± 12.8 months, there was no statistically significant difference between Groups 1 and 2 in terms of clinical, radiological and femoral head avascular necrosis results (P = .591, P = 956, P = .492). The changes in radiological parameters over time and between groups were statistically significant. (P < .001). Only the TDD and c/b ratio were significantly different between groups 1 and 2 (P = .002 and P < .001, respectively). In our study, along with acetabular index, the c/b ratio, teardrop width, TDD, and acetabular teardrop angle significantly changed after SIO and could be used as a guide for patient follow-up.

“Koehlers teardrop is not a reliable landmark for assessing the centre of rotation after Total hip arthroplasty” – a retrospective radiological study

PurposeVarious anatomical landmarks have become established in radiography for the assessment of cup positioning after total hip arthroplasty (THA). The most important one is Koehler's teardrop figure (KTF). However, there is a lack of data on the validity of this landmark, which is widely used clinically for assessing the centre of rotation of the hip.MethodA retrospective measurement of the lateral and cranial distance of the KTF to the centre of hip rotation was performed on the basis of 250 X-ray images of patients who had undergone THA. In addition, the dependence of these distances on pelvic tilt was determined in 16 patients by means of virtual X-ray projections based on pelvic CTs.ResultsIt was shown that the distance of the KTF from the centre of hip rotation in the horizontal plane is gender-dependent (men: 42.8 ± 6.0 mm vs. women: 37.4 ± 4.7 mm; p < 0.001) and age-dependent (Pearson correlation – 0.114; p < 0.05). Furthermore, the vertical and horizontal distances are subject to variation depending on height (Pearson correlation 0.14; p < 0.05 and 0.40; p < 0.001, respectively) and weight (Pearson correlation 0.158; p < 0.05). The distance between the KTF and the centre of hip rotation varies slightly depending on pelvic tilt.ConclusionThe KTF is not a sufficiently valid landmark for assessing the centre of rotation after THA. It is influenced by many different disturbance variables. However, it is largely robust against changes in pelvic tilt, so that it can be used as a reference point when comparing different intraindividual radiographs to assess the change in the centre of rotation due to implantation or to detect cup migration.

Leg length measures appear inaccurate in the early phase following total hip arthroplasty

The aims of this study were to (1) assess reliability of leg length discrepancy (LLD) measurements at different anatomical landmarks, (2) longitudinally investigate LLD in patients within the first year following total hip arthroplasty (THA) and to (3) correlate changes in LLD with functional outcome. Ninety-nine patients with short stem THA (53.3% males, mean age: 61.0 ± 8.1 years) were prospectively included. Upright pelvic anteroposterior (a.p.) radiographs taken at 6 timepoints (preoperatively, discharge, 6, 12, 24, 52 weeks postoperatively) were used to assess LLD at 5 anatomical landmarks (iliac crest, upper sacroiliac joint, lower sacroiliac joint, tear drop figure, greater trochanter). WOMAC and Harris Hip Score (HHS) were obtained preoperatively and at 6 and 52 weeks. LLD measures significantly increased in the initial phase following THA, from discharge to 6 weeks postoperatively and remained constant thereafter. Documentation of LLDs is dependent on measurement site: LLDs varied significantly between trochanter and iliac crest to tear drop figure (p < 0.001). Functional assessments did not correlate with the occurrence of LLDs [WOMAC (p = 0.252); HHS (p = 0.798)]. Radiographic assessment of LLD following THA may not be performed early postoperatively, as measurements appear to inaccurately reflect actual LLDs at this time, potentially due incomplete leg extension and/or inhibited weight-bearing.

Une inégalité de longueur symptomatique après une arthroplastie totale de la hanche est-elle associée à l’apparition de douleurs lombaires ?

BackgroundLeg length discrepancy (LLD) is common after total hip arthroplasty (THA) with a plethora of clinical consequences. The associations between symptomatic (sLLD; disturbing perception of anatomical leg length discrepancy), anatomical (aLLD; side difference in leg length between the center of rotation of the hip and the center of the ankle joint) and intraarticular (iLLD; side difference between the tear drop figure and the most prominent point of the trochanter minor) LLD and lower back have not yet been reported in the literature. We performed a retrospective study to answer if postoperative (1) symptomatic LLD, (2) anatomic LLD, and (3) a change in intraarticular leg length are associated with lower back pain in patients undergoing THA. Further, we aimed to answer (4) whether symptomatic LLD is associated with the magnitude of anatomical LLD and the change in intraarticular leg length. HypothesisLLD after THA is associated with lower back pain. Materials and methodsSeventy-nine consecutive patients were retrospectively analyzed for the presence of aLLD and iLLD using EOS™ and X-rays, and were interviewed for the presence of sLLD and lower back pain using a questionnaire 5 years after primary THA. ResultsPostoperative new onset of lower back pain was reported by 9 (11%) patients. Twenty (25%) patients reported sLLD. Anatomical LLD>5mm was present in 44 (56%) (median 8.0 (IQR -3.0 to 12.0; range -22 to 22) mm) and>10mm in 17 (22%) (median 12.0 (IQR 11.0 to 16.5; range -22 to 22) mm) patients. iLLD changed>5mm in 44 (56%) (median 8.5 (IQR 7.0 to 10.0; range -8 to 18) mm) and>10mm in 10 (13%) (median 14.0 (IQR 12.5 to 14.5; range 11 to 18) mm). New onset lower back pain was associated with sLLD (p=0.002) but not with aLLD or iLLD. Patients without preoperative lower back pain had a statistically significant association between presence of sLLD and an aLLD of>10mm (p=0.01). ConclusionsSymptomatic LLD after primary THA is associated with postoperative new onset of lower back pain irrespective of the magnitude of LLD. In patients without lower back pain prior to THA, symptomatic LLD is associated with anatomical LLD of more than 10mm. Level of evidenceIV.

Symptomatic leg length discrepancy after total hip arthroplasty is associated with new onset of lower back pain

BackgroundLeg length discrepancy (LLD) is common after total hip arthroplasty (THA) with a plethora of clinical consequences. The associations between symptomatic (sLLD; disturbing perception of anatomical leg length discrepancy), anatomical (aLLD; side difference in leg length between the center of rotation of the hip and the center of the ankle joint) and intraarticular (iLLD; side difference between the tear drop figure and the most prominent point of the trochanter minor) LLD and lower back have not yet been reported in the literature. We performed a retrospective study to answer if postoperative (1) symptomatic LLD, (2) anatomic LLD, and (3) a change in intraarticular leg length are associated with lower back pain in patients undergoing THA. Further, we aimed to answer (4) whether symptomatic LLD is associated with the magnitude of anatomical LLD and the change in intraarticular leg length. HypothesisLLD after THA is associated with lower back pain. Materials and methodsSeventy-nine consecutive patients were retrospectively analyzed for the presence of aLLD and iLLD using EOS™ and X-rays, and were interviewed for the presence of sLLD and lower back pain using a questionnaire 5 years after primary THA. ResultsPostoperative new onset of lower back pain was reported by 9 (11%) patients. Twenty (25%) patients reported sLLD. Anatomical LLD>5mm was present in 44 (56%) (median 8.0 (IQR −3.0 to 12.0; range −22 to 22) mm) and>10mm in 17 (22%) (median 12.0 (IQR 11.0 to 16.5; range −22 to 22) mm) patients. iLLD changed>5mm in 44 (56%) (median 8.5 (IQR 7.0 to 10.0; range −8 to 18) mm) and>10mm in 10 (13%) (median 14.0 (IQR 12.5 to 14.5; range 11 to 18) mm). New onset lower back pain was associated with sLLD (p=0.002) but not with aLLD or iLLD. Patients without preoperative lower back pain had a statistically significant association between presence of sLLD and an aLLD of >10mm (p=0.01). ConclusionsSymptomatic LLD after primary THA is associated with postoperative new onset of lower back pain irrespective of the magnitude of LLD. In patients without lower back pain prior to THA, symptomatic LLD is associated with anatomical LLD of more than 10mm. Level of evidenceIV.

Acetabular Protrusio in Patients With Osteogenesis Imperfecta: Risk Factors and Progression.

Osteogenesis imperfecta (OI) is a genetic disorder commonly associated with osteopenia, osteoporosis, bone fractures, bone deformities, and other clinical features. A frequent radiologic finding with OI is acetabular protrusio (AP). We hypothesized that AP develops in patients with OI over time. In addition, we hypothesized that AP also develops in patients with OI without radiographic evidence of AP on initial examination. Medical records and radiographs of 55 patients (109 hips) diagnosed with OI evaluated at our institution were retrospectively reviewed. Previously established radiographic criteria using the center-edge (CE) angle of Wiberg, position of the acetabulum relative to the iliopectineal line, crossing of the acetabulum across the ilioischial (Kohler) line, and position of the teardrop figure relative to the ilioischial (Kohler) line were utilized to assess AP severity. In addition, pharmacological treatments and patient factors including body mass index (BMI) were recorded. Radiographs of patients with OI that were taken ≥2 years apart were analyzed utilizing AP radiographic criteria to assess for changes. The changes in AP-related measurements were standardized by distance or degree per year. In addition, patient factors were evaluated for associations with AP development. In this series of 109 hips (55 patients), incidence of AP in earliest radiographs was 45% (49/109). Patients with OI type I and III demonstrated the highest incidence of AP (65%). Among the hips that did not meet the criteria for AP in their early radiographs, 24 (40%) were positive for AP by their latest radiograph. In the hips that initially presented with AP, 42% showed increased CE angles on later radiographs. Twenty-six hips (24%) showed either no observable changes or reduced CE angles. Risk factors that were significantly associated with greater odds of developing AP included (1) an age under 12; (2) a BMI>25; (3) presence of AP of the contralateral hip; and (4) female sex. Bisphosphonates, vitamin D, physical therapy, and other drugs related to treatment of OI reduced the risk of developing AP but did not achieve statistical significance. AP is a common finding in OI patients (54%). Among hips of OI patients that met criteria for AP in early radiographs, 42% (20/48) demonstrated greater CE angles in their latest radiographs. Similar changes were observed in OI patients who did not initially meet criteria for diagnosis for AP. However, CE angle measurements between the 2 groups did not significantly differ (P=0.71). In terms of Kohler line crossing, patients that met criteria for AP in early radiographs had significantly greater change per year than those that did not have AP criteria (P<0.05). The findings suggest AP may develop over time in patients with OI and may be influenced by patient factors such as age, sex, and BMI. In addition, unilateral AP may have a significant impact on the development of AP of the contralateral hip. Level IV-retrospective case series.

Successful Pavlik Harness Treatment for Developmental Dysplasia of the Hip and Normal X-Ray at the Age of 2 Years: Is a Longer Follow-up Necessary?

Management of developmental dysplasia of the hip (DDH) with a Pavlik harness is a well-known treatment.Follow-up until skeletal maturity is recommended as long-term studies mention late sequelae.The purpose of this study was to determine whether such a follow-up is necessary in patients treated successfully under a strict protocol. A retrospective review of a consecutive series of normal infants treated for DDH between January 1995 and July 2004 was undertaken.Only normal infants with frankly pathologic hips treated successfully with a Pavlik harness were included, and with a normal anteroposterior (AP) pelvis x-ray at the age of 2 years.All infants with any type of neurological disease, syndrome, other form of treatment for DDH, and failure of the Pavlik harness were excluded.At the last follow-up, a clinical examination and a standing AP pelvis x-ray were performed. A total of 109 hips in 83 children were available for review. The mean follow-up was of 10 years and 2 months. All 109 hips had a normal clinical examination and a normal AP pelvis x-ray: a mean center-edge angle (CEA) of 29.5 degrees, SD±4.1 degrees, a mean acetabular index (AI) of 1457±3.74 degrees, a mean Sharp's angle of 41.92±3.42 degrees, a Seringe-Severin score of IA, a normal teardrop figure, no signs of avascular necrosis, and Moses circles <2. This study strongly suggests that in a selected group of patients treated for DDH with a Pavlik harness, under a strict protocol, and a normal x-ray at 2 years of age, a long-term follow-up is not necessary. Level III-therapeutic.

Acetabular Protrusio and Proximal Femur Fractures in Patients With Osteogenesis Imperfecta.

Osteogenesis imperfect (OI) is a genetic disorder characterized by increased bone fragility, frequent fractures, and extremity deformities among other clinical findings. A frequent radiographic finding in OI patients is acetabular protrusio (AP). We hypothesized that AP incidence would be significant in OI patients and highest among type III OI patients, who have a more severe disease phenotype. In addition, we hypothesized that there would be a correlation between AP and proximal femur fracture incidence. We retrospectively reviewed radiographs and medical records of 49 patients with OI evaluated at our institution. Demographic information and modified Sillence classification were recorded. AP was diagnosed using previously published radiographic criteria using the center-edge angle of Wiberg, acetabulum relative to the iliopectineal line, teardrop figure relative to the ilioischial (Kohler) line, and acetabulum relative to the ilioischial (Kohler) line. Medical record and radiographs were reviewed for evidence of proximal femur or acetabulum fracture. Associations between OI type, AP, and fracture incidence were examined with χ or Fisher exact tests. In this series of 49 OI patients, the overall incidence of AP was 55.1% (27/49) with the highest incidence among patients with type III OI (70.6%). There was an increased incidence of proximal femur, and particularly femoral neck, fractures among patients with AP compared with patients with normal hip anatomy. Overall, patients with AP had a 30% increased risk for proximal femur and acetabulum fractures (P=0.03). AP is a common deformity in OI patients (55.1%) and particularly type III OI (70.6%). Patients with AP have an increased risk for proximal femur fractures and particularly femoral neck fractures. This novel finding adds to the growing body of literature on clinical implications of AP in OI patients. Level IV-Retrospective case series.

Validation of a standardized mapping system of the hip joint for radial MRA sequencing.

Intraarticular gadolinium-enhanced magnetic resonance arthrography (MRA) is commonly applied to characterize morphological disorders of the hip. However, the reproducibility of retrieving anatomic landmarks on MRA scans and their correlation with intraarticular pathologies is unknown. A precise mapping system for the exact localization of hip pathomorphologies with radial MRA sequences is lacking. Therefore, the purpose of the study was the establishment and validation of a reproducible mapping system for radial sequences of hip MRA. Sixty-nine consecutive intraarticular gadolinium-enhanced hip MRAs were evaluated. Radial sequencing consisted of 14 cuts orientated along the axis of the femoral neck. Three orthopedic surgeons read the radial sequences independently. Each MRI was read twice with a minimum interval of 7 days from the first reading. The intra- and inter-observer reliability of the mapping procedure was determined. A clockwise system for hip MRA was established. The teardrop figure served to determine the 6 o'clock position of the acetabulum; the center of the greater trochanter served to determine the 12 o'clock position of the femoral head-neck junction. The intra- and inter-observer ICCs to retrieve the correct 6/12 o'clock positions were 0.906-0.996 and 0.978-0.988, respectively. The established mapping system for radial sequences of hip joint MRA is reproducible and easy to perform.

Results of the cementless Plasmacup in revision total hip arthroplasty: a retrospective study of 72 cases with an average follow-up of eight years

BackgroundThere are multiple revision implant systems currently available for socket revision in revision total hip arthroplasty. Up until now, not all of these systems have been followed up with regards to their long-term use as a revision implantation.For the first time, this study presents the hemispherical porous-coated socket Plasmacup SC, produced by Aesculap, Tuttlingen, Germany, and the clinical and radiological mid-term results of this revision cup implant.MethodsOver a period of ten years the Plasmacup SC press-fit-cup was used as a revision implant in 72 consecutive aseptic cases which were included in this retrospective study. The mean follow-up period was 8 years. Bone graft transplantation was performed in 32% of all cases. In 90%, the cup was fixed with additional screws. The follow-up radiographs were analysed with regards to cup migration, osteointegration and osteolysis in the DeLee zones using a computer aided program taking the teardrop figure as a main point of reference. For clinical evaluation the Harris-Hip-Score and the WOMAC-Score were utilized.ResultsAt the follow up examination, the mean Harris-Hip-Score was 83.5 points and the mean WOMAC-Score 34.7 points. 93% of all patients were satisfied with the result of the operation. No aseptic cup loosening could be observed and only one cup had to be removed due to infection. No significant longitudinal or transversal cup migration could be observed.ConclusionAesculap's Plasmacup SC is suitable as a cementless cup revision implant. There is stable cup osteointegration, post press-fit implantation, even in the case of major acetabular bone defects.

Diagnose und Therapie der Hüftdysplasie des älteren Kindes

Diagnosis of congenital hip dysplasia is based on normal values of the acetabulum, but also criteria such as deficiency of the acetabular rim and an increased distance from the tear drop figure. Instability of the hip joint is seen in arthography. Acetabuloplasty is the way to treat it. Unstable joints will deteriorate, stable ones are frequently improving spontaneously. The technique of open reduction from an inguinal approach medial of the psoas muscle is described. There are many advantages. Simultaneous shortening osteotomy and acetabuloplasty to permit immediate movements out of the hip spica are recommended to avoid stiffening and contractures. Hip dysplasia is corrected by a lateral acetabuloplasty that levers down the acetabular roof in the triradiate cartilage. After consolidation of the cartilage triple pelvic osteotomy for acetabular rotation is the method to correct dysplasia in adolescents and adults. The closer the osteotomies are performed to the hip joint, the better rotation is possible. Our technique has proved successful now in 12 years.

Structural femoral head allografts in revision surgery of loosened acetabular cups

Treatment of acetabular bone defects presents a great challenge in revision total hip arthroplasty (THA). Many methods of acetabular reconstruction have been described. The purpose of this study was to evaluate the midterm results of structural femoral head allografts for acetabular reconstruction. Thirty-six patients (33 females and 3 males) with acetabular defects ranging from type 2C to type 3B according to Paprosky's classification were included in the study. In all cases acetabular defects were closed using allografts from femoral heads. In 13 cases an uncemented press-fit cup, in 17 cases a cemented polyethylene socket, and in 6 cases a Burch-Schneider antiprotrusion cage was implanted. The mean follow-up period was 84.2 months (range: 5-147). Four acetabular components failed. All 36 grafts were osseointegrated radiographically and formed a mechanically stable construction. The mean Harris Hip Score at the most recent follow-up was 79.8 points. The distance from the obturator line to the prosthesis head center was 3.73 cm (1.17-5.80 cm) preoperatively and 2.79 cm (0.85-4.8 cm) postoperatively (p<0.05). The distance from the teardrop figure to the prosthesis head center was 3.02 cm (1.0-5.8 cm) preoperatively and 3.25 cm (1.6-4.8 cm) postoperatively (p<0.001). Closure of acetabular defects of types 2C to 3B according to Paprosky's classification can be satisfactorily accomplished using femoral head allografts. These allografts may facilitate future revision surgery. Femoral heads are readily available due to widespread primary total hip replacement surgery. However, the use of structural femoral head allografts for acetabular reconstruction is cost intensive. Individual patient-related aspects, such as the function of revision arthroplasty, have to be considered when planning revision arthroplasty using femoral head allografts.

Anatomic and Radiographic Considerations for Placement of Transiliac Screws in Lumbopelvic Fixations

Lumbopelvic fixation in spinal and pelvic surgery relies on rods or screws as an iliac anchor. Secure placement of screws with maximum diameter and length for the greatest pullout strength requires knowledge of the iliac structure and of intraoperative fluoroscopic landmarks for secure placement. Therefore, the authors evaluated the intrailiac length, inner width, and cortical thickness of three different transiliac screw anchor paths aimed toward the anterior inferior iliac spine and initiated at the iliac tubercle, posterior superior iliac spine, or posterior inferior iliac spine. Measurements were made using two- and three-dimensional computed tomographic reformations in 40 consecutive trauma patients (27 measurements in 21 males, 16 to 75 years old; 28 measurements in 19 females, 16 to 78 years old). In addition, fresh and dry human cadaveric specimens were marked with metal wires at the previously determined optimal screw path to determine fluoroscopic landmarks for easiest and best controlled transiliac screw placement. The posterior superior iliac spine-anterior inferior iliac spine path had the largest bony canal lengths, with 141 mm in male and 129 mm in female patients. Two stereotypic iliac constrictions allowed placement of 8-mm implants in male and 6- to 7-mm implants in female patients. Cortical thickness at that optimal extraarticular path was 5.2 mm in the male and 4.7 mm in the female patients. Transiliac screws can be placed during operation under fluoroscopic control using standard lateral and obturator oblique-outlet views, the latter presenting a stereotypical teardrop figure above the acetabulum.

The Predictive Value of the Development of the Acetabular Teardrop Figure in Developmental Dysplasia of the Hip

Summary: We reviewed the radiographs of 72 hips, 47 with developmental dysplasia of the hip (DDH), and 25 normal hips, to determine the timing of the normal appearance of the acetabular teardrop figure and the value of teardrop development after reduction of the hip in predicting outcome. In normal hips, all children had a teardrop figure by age 18 months. In the 47 hips with DDH, no teardrop figure appeared until the hip was reduced. The DDH hips were divided into two groups based on the success of the initial reduction. By using statistical analysis, we found that the appearance of the acetabular teardrop within 6 months after reduction of the hip is strongly associated with a favorable long-term outcome. We believe that the appearance of the teardrop is the earliest radiographic sign that a stable, concentric reduction of the hip has been achieved

The predictive value of the development of the acetabular teardrop figure in developmental dysplasia of the hip.

We reviewed the radiographs of 72 hips, 47 with developmental dysplasia of the hip (DDH), and 25 normal hips, to determine the timing of the normal appearance of the acetabular teardrop figure and the value of teardrop development after reduction of the hip in predicting outcome. In normal hips, all children had a teardrop figure by age 18 months. In the 47 hips with DDH, no teardrop figure appeared until the hip was reduced. The DDH hips were divided into two groups based on the success of the initial reduction. By using statistical analysis, we found that the appearance of the acetabular teardrop within 6 months after reduction of the hip is strongly associated with a favorable long-term outcome. We believe that the appearance of the teardrop is the earliest radiographic sign that a stable, concentric reduction of the hip has been achieved.

The Value of the Acetabular Teardrop Figure in Assessing Pediatric Hip Disorders

We have observed that the acetabular teardrop figure provides extremely useful information about the development of the hip in young children. Normal development of the acetabulum is associated with progressive narrowing of the teardrop figure and development of a concave shape to its acetabular line. Anatomic and functional abnormalities of the hip can cause abnormalities of the teardrop figure, including absence of the acetabular line, persistent widening, and a V-shaped teardrop figure. In young children, these abnormalities can be reversed to some degree by stabilizing operations, but it is unusual to observe substantial change in appearance of the teardrop figure after a child is aged 8 years.

The Value of the Acetabular Teardrop Figure in Assessing Pediatric Hip Disorders

The Value of the Acetabular Teardrop Figure in Assessing Pediatric Hip Disorders

The Acetabular Teardrop and Its Relevance to Acetabular Migration

Five pelvises were photographed, roentgenographed, and sequentially sectioned or reamed to determine the location and appearance of the acetabular teardrop figure. The teardrop is located inferomedially in the acetabulum, just superior to the obturator foramen. The lateral lip is the exterior, and the medial lip is the interior of the acetabular wall. The ilioischial line projects over the medial acetabulum only fortuitously on the straight anteroposterior (AP) roentgenogram. Because of parallax, the relationship between the ilioischial line and the teardrop changes for views varying as little as 10 degrees in horizontal obliquity from the true AP roentgenogram. Because the teardrop comprises a well-defined, constant portion of the medial acetabular wall whereas the ilioischial line does not, the authors recommend using the acetabular teardrop rather than the ilioischial line for the detection and measurement of medial and superior acetabular migration.