Editorial Commentary: Borderline Hip Dysplasia Combined With Increased Anteversion and Ligamentum Teres Disruption Is a Recipe for Hip Microinstability.

The ligamentum teres (LT) is known to play a role as a secondary stabilizer of the hip joint. LT tears can be associated with hip instability. In patients with borderline developmental dysplasia of the hip (BDDH), the correlation between LT tears and microinstability is even more pronounced because of the increased mechanical stress placed on the ligament. This relationship may lead certain surgeons to consider new indications for LT reconstructions. However, caution is warranted regarding the potential role of LT reconstruction in these patients, particularly since the primary deficiency in BDDH is bony undercoverage. Addressing this bony undercoverage should be a primary consideration that may be supplemented with other procedures, which may include addressing soft-tissue injuries around the hip such as LT tears. This is especially the case in those patients with persistent symptoms after management of labral tears or LT disruption.

MRI Is Better Than CT Scan for Detection of Structural Pathologies After Traumatic Posterior Hip Dislocations in Children and Adolescents.

BACKGROUND: Traumatic posterior hip dislocations in children and adolescents requires emergent closed reduction. Postreduction imaging is necessary to assess the concentricity of reduction and structural injuries to the hip. There is no a consensus for which imaging is a modality of choice in such condition. The purposes of this study are to describe magnetic resonance imaging (MRI) findings of traumatic posterior hip dislocations and to compare the effectiveness of MRI with computerized tomography (CT) in detecting structural abnormalities of the hip that impact patient management. METHODS: This study is a retrospective review of imaging in traumatically dislocated hips in patients who were treated at our institution. All CT and MRI imaging were reviewed and specific osseous and soft tissue injuries documented by consensus among 2 musculoskeletal pediatric radiologists who interpreted the MRI and CT scans of each patient in a blinded manner. RESULTS: In total, 27 patients (23 males, 4 females) with mean age of 12.5 years (range, 2 to 19 y) with postreduction MRI were evaluated. MRI findings revealed femoral head injuries in 17 (62.9%), posterior labral entrapments in 6 (22.2%), posterior labral tears in 17 (62.9%), posterior wall fractures in 15 (55.5%), fracture of the posterior unossified part of acetabulum in 4 (14.8%), and ligamentum teres injuries in 8 (29.6%). Of 16 patients who had postreduction CT scans, 6 (37.5%) had femoral head fractures, 9 (56.3%) had posterior wall fractures, and 8 (50%) had intra-articular osseous entrapments. All bony fractures and intra-articular entrapment could be seen on MRI imaging. In 16 patients with both CT and MRI, posterior acetabular injury was detected in 10/16 (62.5%) on MRI and 9/16 (56.3%) on CT. Three patients with entrapment of labrums identified on MRI could not be seen on CT scan. One patient with persistently unstable hip after reduction had an entrapped unossified portion of acetabular fracture which was seen on MRI but not on CT. CONCLUSIONS: MRI is superior to CT scan for detection of structural injuries in children and adolescents with traumatic hip dislocation. The unique structural injuries included entrapment of posterior labrum and posterior unossified acetabular fractures could be seen only at MRI. These findings will impact surgical decision making of these injuries. LEVEL OF EVIDENCE: Level IV.

Bilateral Hip Arthroscopy: Can Results From Initial Arthroscopy for Femoroacetabular Impingement Predict Future Contralateral Results?

PURPOSE: To determine the degree of correlation of radiographic measurements, degree of correlation of intraoperative pathology, and difference in outcomes between sides of patients requiring staged bilateral hip arthroscopy. METHODS: Two high-volume hip preservation centers retrospectively reviewed hip preservation databases for staged bilateral hip arthroscopies conducted between 2008 and 2015. Patients were separated into those who presented with bilateral hip pain and those that presented with unilateral pain and developed contralateral pain >2 years later. Patients were analyzed for radiographic correlation (alpha angle, lateral center edge angle, anterior center edge angle, magnetic resonance imaging alpha angle, Tönnis grade) and correlation of intraoperative pathology (acetabular labrum articular disruption grade, Outerbridge grade/location, Villar class ligamentum teres tears, labral tear location, symmetry of Seldes tear types, and the differences between operative procedures). Patient-reported outcomes were analyzed (modified Harris Hip Score, Non-Arthritic Hip Score, International Hip Outcome Tool-12, hip outcome score-sport specific subscale, visual analog scale, patient satisfaction). Correlative tests included Pearson and Spearman; univariate and multivariate analysis for differences included χ-square test and Student t tests for ordinal and continuous variables respectively. RESULTS: A total of 133 of 2,705 patients (4.6%) underwent bilateral hip arthroscopy. Radiographic alpha angle, magnetic resonance imaging alpha angle, lateral center edge angle, and anterior center edge angle demonstrated strong correlation (Pearson's coefficients 0.651, 0.648, 0.644, 0.667, respectively, P < .0001). Tönnis grade was weakly correlated (Pearson's coefficient 0.286, P = .001). Intraoperative pathology was moderately correlated (Pearson's coefficients for acetabular Outerbridge location, 0.300, P = .0170; acetabular labrum articular disruption, 0.490, P < .0001; acetabular Outerbridge; 0.530; P < .0001; femoral head Outerbridge, 0.459, P < .0001; Villar class, 0.393, P < .0001; and labral tear location, 0.468, P < .0001). Labral tear Seldes type was compared with Bowker's symmetry test and there was no significant difference between sides. There were no significant differences in surgical interventions performed between sides. Patients with bilateral hip arthroscopies significantly improved in all measured patient-reported outcomes and had a high patient satisfaction after both procedures. Final patient-reported outcomes and change in patient-reported outcomes were not different between procedures; follow up ranged from 3 months to 8 years. CONCLUSIONS: This study demonstrated an incidence of 4.6% of patients who require bilateral hip arthroscopy. These patients can expect significant improvement after surgical intervention. Patients that had 1 side done gained similar improvement when the contralateral side was performed. Preoperative radiographic, intraoperative pathology, and procedures performed were similar between hips. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

The Effect of Complete Tearing of the Ligamentum Teres in Patients Undergoing Primary Hip Arthroscopy for Femoroacetabular Impingement and Labral Tears: A Match-Controlled Study.

PURPOSE: To compare the patient-reported outcomes scores (PROs) of patients with femoroacetabular impingement (FAI), labral tears, and complete ligamentum teres (LT) tears to a matched-pair control group with intact LTs, as well as to report the relative risk of total hip arthroplasty (THA) conversion. METHODS: Data between February 2008 and April 2015 were retrospectively reviewed. Patients undergoing hip arthroscopy included those who had complete LT tear, labral tears, FAI, and minimum 2-year follow-up with modified Harris Hip Score (mHHS), Non-arthritic Hip Score (NAHS), Hip Outcome Score-Sports Specific Subscale (HOS-SSS), International Hip Outcome Tool-12 (iHOT-12), and visual analog scale (VAS). Patients were excluded for Tönnis osteoarthritis grade >1, previous hip conditions or surgeries, and Worker's Compensation claims. Patients with full LT tears were matched in a 1:3 ratio with patients without LT tears based on age at surgery ± 5 years, sex, body mass index ± 5, capsular treatment, and acetabular Outerbridge grade. Revision surgeries and conversions to THA were documented. Relative risk for conversion to THA was determined (P = .05). RESULTS: Eighteen patients (18 hips) had minimum 2-year follow-up and were eligible for matching; as described, each study group patient was matched to 3 control patients, resulting in a size of 18 to 54 patients. PROs showed significant improvement in the complete LT tear group with the exception of the HOS-SSS measure. In the intact LT control group, all PROs significantly improved, with no exception. Based on relative risk, patients with complete LT tears were 3 times more likely to require THA than a matched control group. CONCLUSIONS: After hip arthroscopy, patients with FAI and complete LT tears reported significant improvement in PROs. Among hips that did not require THA, functional scores were comparable to a matched control group. However, patients with complete LT tears were 3 times more likely to require an eventual THA than the matched control group. We conclude that patients with complete LT tears should be considered an at-risk population, and that indications and treatment may be refined to incorporate the clinical significance of complete LT tears. LEVEL OF EVIDENCE: Level III, comparative trial, case-control.

Non-traumatic ligamentum teres tears: association with MRI morphometry of the hip.

BACKGROUND: The ligamentum teres has been recognized as an important stabilizer of the hip. PURPOSE: We aimed to examine the relationship between non-traumatic ligamentum teres (LT) tear and hip morphometry on magnetic resonance imaging (MRI). MATERIAL AND METHODS: Fifty patients who had undergone hip MRI were included (27 men, 23 women; average age = 54.0 years). The status of the LT and the morphometric hip parameters were assessed, including acetabular anteversion angle (AAA), acetabular depth (AD), acetabular index (AI), lateral center edge angle (LCEA), and extrusion index (EI). The morphometric hip parameters were compared between groups with one-way ANOVA, Student's t-test, and Mann-Whitney U test. RESULTS: A decreased acetabular coverage was noted in the severe tear group compared to the normal group, indicated by a significantly larger AD ( P = 0.001) and smaller LCEA ( P = 0.016). There was a statistically significant difference in the AAA, AD, and LCEA between the normal group and the complete tear group; the AAA was significantly larger ( P = 0.031), the AD was significantly larger ( P = 0.01), and the LCEA was significantly smaller ( P = 0.043) in the complete tear group compared to the normal group. CONCLUSION: There is an association between LT tears and acetabular bony morphology; an insufficient acetabular coverage is associated with complete tear of the LT. As the insufficient acetabular coverage may predispose to ligamentum teres tear, the ligamentum teres should be thoroughly evaluated in those with insufficient acetabular coverage, as a potential cause of hip pain.

Metástasis poco frecuente del carcinoma renal de células claras / Unusual metastasis of clear cell renal cell carcinoma

El ligamento falciforme es una reflexión peritoneal abdominal relacionada con la superficie anterior del hígado, que en su borde inferior libre contiene el ligamento redondo (LR); las lesiones únicas en este son infrecuentes. Presentamos un caso de metástasis única en el ligamento redondo en un paciente con antecedente de carcinoma renal de células claras. Realizamos una búsqueda bibliográfica para identificar casos similares. Nuestro paciente es un varón de 71 años con antecedente de carcinoma renal de células tratado con nefrectomía radical izquierda laparoscópica (estadio pT3a). En tomografía computarizada (TC) control a los 5 años se evidencia lesión focal en la periferia del segmento IVa, ante la sospecha de malignidad, se realiza laparotomía exploradora revisando toda la cavidad abdominal sin evidenciar otros implantes peritoneales. Se halla un nódulo de 1 cm en el ligamento redondo y se realiza su exéresis completa, con diagnóstico anatomopatológico de metástasis de células claras. El LR generalmente está afectado en casos de carcinomatosis peritoneal y solo existen dos casos publicados de metástasis únicas.

The falciform ligament is a peritoneal reflection that attaches the liver to the anterior abdominal wall; its lower edge contains the round ligament (RL). Single lesions in the RL are rare and usually correspond to perivascular epithelioid cell tumors. We present a case report of a single metastasis in the RL in a patient with clear cell renal cell carcinoma who underwent surgery five years ago. We conducted a literature review to identify similar cases and we found two case reports of single metastasis in the RL. Our patient was a 71-year-old man with a history of renal cell carcinoma who underwent left laparoscopic radical nephrectomy (stage pT3a), laparoscopic right adrenalectomy and total thyroidectomy due to multinodular goiter. The pathological examination revealed metastases of renal cell carcinoma. A computed tomography (CT) scan performed at 5-year follow-up showed a focal lesion in segment IVa with no FDG uptake in the PET scan, but as malignancy was suspected, the patient underwent exploratory laparatomy with no evidence of peritoneal implants. A 1-cm node was found in the round ligament that was completely resected. The pathological examination revealed metastatic clear cell renal cell carcinoma. The RL is involved in cases of peritoneal carcinomatosis and only two cases of single metastasis have been reported: in one patient with papillary renal cell carcinoma pT1aN0 and another one with left breast adenocarcinoma.

Posterior Bony Impingement-Potential Mechanism of Ligamentum Teres Tears.

PURPOSE: 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. METHODS: 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 24 months (mean, 29 months; range, 24-38 months). RESULTS: 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 2 years after surgery. There were no complications associated with the procedure and no revision surgeries performed over the 2-year follow-up. CONCLUSIONS: 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 2 years. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Contribution of the Ligamentum Teres to Hip Stability in the Presence of an Intact Capsule: A Cadaveric Study.

PURPOSE: To determine the contribution of the ligamentum teres (LT) to hip stability in the presence of an intact capsule with special attention to the change in range of motion and femoral head translation. METHODS: Seven fresh-frozen cadaveric pelvises were used. Following visual inspection of the LT at different hip positions, internal rotation angles were measured at 10° of extension and at 0° of flexion, while external rotation was measured at 60°, 90°, and 110° of flexion with different hip abduction angles using electromagnetic motion tracking sensor. Femoral head translations were measured simultaneously. The tests were repeated after resection of the LT. The capsule was left intact for all test conditions. The results were compared between intact and LT resected conditions when torque of 2 and 4 Nm was applied. RESULTS: Compared with the intact hip, the LT resected hip showed no significant difference when 2 Nm torque was applied in all scenarios. With 4 Nm torque application, significant increase in external rotation was found at 60° and at 90° of flexion (1.7° ± 0.8° and 2.1° ± 1.0°, respectively). Significant difference was also noted at 60°, 90°, and 110° of flexion when the hip was in the adducted position while at 90° in the abducted hip. However, LT resection did not show significant change in internal rotation. There was no significant difference in the translation distance of the femoral head in the intact hip compared with the LT resected hip (0.77-1.11 mm vs 0.79-1.29 mm). CONCLUSIONS: Our results indicate that within the physiologic range of motion, LT can minimally limit external rotation when the hip is in the flexed position but does not contribute to translation stability. CLINICAL RELEVANCE: In the hip with intact capsule, LT deficiency can result in a slight increase in range of motion, but its contribution to stability is questionable.

Central Acetabular Impingement Is Associated With Femoral Head and Ligamentum Teres Damage: A Cross-Sectional Matched-Pair Analysis of Patients Undergoing Hip Arthroscopy for Acetabular Labral Tears.

PURPOSE: The primary purpose of this study was to report the prevalence of femoral head articular damage in patients with a central acetabular osteophyte (CAO) that was identified during hip arthroscopy and compare it with that in a matched control group without a CAO. A secondary purpose was to identify rates of coexisting intra-articular pathology in both patient groups. METHODS: Intraoperative data were collected prospectively on all hip arthroscopy patients at our institution between 2008 and 2015. The inclusion criteria for this study were CAOs identified during hip arthroscopy for a labral tear and/or femoroacetabular impingement. The exclusion criteria were Tönnis grade greater than 0, previous hip conditions, and prior surgical interventions. The matched control group was selected based on sex, age ± 5 years, body mass index, and Workers' Compensation claim at a 3:1 ratio and comprised patients who underwent hip arthroscopy for a labral tear and/or femoroacetabular impingement without a CAO. The size and location of labral tears and chondral lesions were recorded in square millimeters with a 5-mm probe and by the clock-face method. RESULTS: The CAO group consisted of 126 patients, who were matched to 378 patients in the control group. Femoral and acetabular chondral damage grades were significantly different between the 2 groups (P < .001). Of patients with CAOs, 55% had femoral head chondral damage compared with 24% of the control patients. The mean size of femoral chondral damage was 3.2 cm2 in the CAO group and 1.7 cm2 in the control group. The mean size of acetabular chondral damage was 1.7 cm2 in the CAO group and 1.2 cm2 in the control group. Both femoral and acetabular chondral damage sizes were significantly larger in the CAO group (P ≤ .007). The prevalence of ligamentum teres tears was significantly different between the 2 groups (P < .001). There were no statistically significant differences in the types of labral tears between the 2 groups (P = .625). CONCLUSIONS: This study showed that patients with CAOs had a significantly higher prevalence of femoral chondral damage and ligamentum teres tears than matched controls. LEVEL OF EVIDENCE: Level III, comparative study.

Effect of ligamentum teres tear on the development of joint instability and articular cartilage damage: an in vivo rabbit study.

The contribution of the ligamentum teres to the stabilization of the hip joint and the clinical influence of a compromised ligamentum teres are not well known. This study aimed to investigate joint stability and cartilage damage in a rabbit model by surgically inducing a complete ligamentum teres tear. Twenty adult New Zealand rabbits were used in this study. Rabbits were divided into complete ligamentum teres tear with capsulotomy (n = 9, group I) and capsulotomy only (n = 10, group II) groups. Unilateral surgery was performed on the left hip. Joint instability was assessed by measuring the preoperative and postoperative acetabulofemoral (A-F) distances. Rabbits were euthanized to assess cartilage damage at 24 weeks postoperatively. The median postoperative A-F distance of the operated side in group I [0.68 cm (0.37-1.04 cm)] was larger than that in group II [0.50 cm (0.30-0.65 cm)] (p = 0.041). The median postoperative A-F distance was larger in the operated side [0.68 cm (0.37-1.04 cm)] compared to the nonoperated side [0.45 cm (0.30-0.75 cm)] in group I; it also was larger in the operated side [0.50 cm (0.30-0.65 cm)] compared to the nonoperated side [0.44 cm (0.32-0.67 cm)] in group II, but only group I showed a significant difference (p = 0.016 and 0.395, respectively). Articular cartilage damage was detected at the apex of the femoral head in two rabbits (22.2%) in group I only. Rabbits with a complete ligamentum teres tear showed significant instability at the hip joint and articular cartilage damage in our rabbit model, supporting the potential clinical importance of ligamentum teres as a hip joint stabilizer.

Arthroscopy After Traumatic Hip Dislocation: A Systematic Review of Intra-articular Findings, Correlation With Magnetic Resonance Imaging and Computed Tomography, Treatments, and Outcomes.

PURPOSE: To describe the literature concerning patient demographic characteristics and intra-articular injury seen at arthroscopy after traumatic hip dislocation, describe the reported computed tomography (CT) and magnetic resonance findings with arthroscopic correlation, and describe the reported arthroscopic treatments performed with complications and outcomes. METHODS: A systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines for assessment of arthroscopy after hip dislocation. Three databases were searched, and study screening and data abstraction were performed in duplicate. RESULTS: Thirty-one heterogeneous case series and case reports were included in the analysis from the initial search yielding 780 results, including reports of 151 patients who underwent arthroscopy after traumatic hip dislocation. A wide spectrum of intra-articular injury was reported, with a high prevalence of labral tears, intra-articular bodies, ligamentum teres injuries, and chondral damage. CT had a sensitivity of 87.3% for detecting intra-articular fragments; however, 43.3% of patients who had a preoperative CT scan with negative findings for intra-articular fragments did show fragments at arthroscopy. Magnetic resonance had a sensitivity of 95.0% for detecting labral tears. There were no major complications directly attributed to arthroscopic surgery. A total of 75 of 151 patients were followed up for a median of 2 years after surgery, with osteoarthritis reported in 4.0% and avascular necrosis in 2.7%. CONCLUSIONS: In patients with traumatic hip dislocation, heterogeneously reported previously published cases show that arthroscopy reveals a broad spectrum of intra-articular damage amenable to arthroscopic intervention. CT is not sensitive in the detection of intra-articular bodies in all cases. Although no serious periprocedural adverse events were reported, only 49.7% of patients had reported follow-up data, and further prospective studies would be necessary to show the safety and efficacy of arthroscopy in comparison with conventional treatment algorithms of hip dislocation. LEVEL OF EVIDENCE: Level IV, systematic review of Level IV studies.

Outcomes of arthroscopic debridement of isolated Ligamentum Teres tears using the iHOT-33.

BACKGROUND: Tears of the Ligamentum Teres are a common cause of groin pain. Tears of the ligament frequently co-exist alongside other bony or labral intra-articular hip lesions, which are also treated at the time of arthroscopy. For this reason, it is often difficult to assess the effect that debridement alone has on improving patient pain and function. This study aims to assess the short-term outcomes of arthroscopic debridement of isolated Ligamentum Teres tears using a validated patient-reported outcome score - the International Hip Outcome Tool (iHOT-33). METHODS: A retrospective review was performed of 35 patients (37 hips) who had an isolated Ligamentum Teres tear treated with arthroscopic radiofrequency debridement between September 2012 and September 2015. Patients with concomitant intra-articular hip pathology (femoroacetabular impingement, labral lesions, hip dysplasia) were excluded from the study. All patients completed the iHOT-33 questionnaire pre-operatively and post-operatively. The mean age was 37.7 years (range 16-67 years) and patients were followed up for a mean period of 17.7 months (range 6-42 months). Thirty-one patients were female and 4 were male. RESULTS: Thirty-seven isolated partial tears were managed with arthroscopic radiofrequency debridement. At follow up, the mean iHOT-33 score improved from 26.9 pre-operatively to 48.0 post-operatively, representing a mean improvement of 21.1 (p < 0.001). The minimum clinically important difference of the iHOT-33 is 6.1 points. Significant improvements were noted in all four sub-sections of the iHOT-33. CONCLUSION: Arthroscopic radiofrequency debridement of isolated Ligamentum Teres tears provides short-term benefit in the majority of patients, including significant improvement in sporting function.

Do Ligamentum Teres Tears Portend Inferior Outcomes in Patients With Borderline Dysplasia Undergoing Hip Arthroscopic Surgery? A Match-Controlled Study With a Minimum 2-Year Follow-up.

BACKGROUND: Arthroscopic surgery in borderline dysplastic hips remains controversial, but the role of the ligamentum teres (LT) has not been studied in this setting. HYPOTHESIS: Borderline dysplastic patients with LT tears have worse short-term outcomes than those without LT tears. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Data were prospectively collected on patients who underwent arthroscopic surgery between February 2008 and April 2014. The inclusion criteria were borderline dysplasia (lateral center-edge angle [LCEA], 18°-25°) and labral tears; arthroscopic treatments including labral preservation and capsular plication; and preoperative patient-reported outcome scores including the modified Harris Hip Score (mHHS), Non-Arthritic Hip Score (NAHS), Hip Outcome Score-Sport-Specific Subscale, and visual analog scale for pain. Patients were excluded for preoperative Tönnis osteoarthritis grade >0, workers' compensation claims, previous ipsilateral hip surgery and conditions, or frank dysplasia (LCEA <18°). Patients with LT tears were pair-matched to patients without tears for sex, age at surgery ±10 years, body mass index (<30 kg/m2 vs ≥30 kg/m2), labral treatment type, and microfracture. RESULTS: Of 68 eligible patients, 63 (93%) had a minimum 2-year follow-up, and 30 (48%) had LT tears. Twenty patients in each group were pair-matched. The mean follow-up time was 54.3 months (range, 24.2-83.8 months) for the LT tear group and 38.6 months (range, 24.6-70.6 months) for the control group ( P = .002). Ninety percent were female. There were no significant differences regarding demographics or intra-operative procedures. The LT tear group trended toward lower postoperative mHHS ( P = .09) and NAHS ( P = .09) values. Mean satisfaction was 8.1 for the LT tear group and 7.9 for the control group. Preoperative and follow-up scores were not significantly different between the groups. The LT tear group had 5 revisions, with 1 revision in the control group. Three patients (15%) in the LT tear group underwent total hip arthroplasty (THA); no patients in the control group required THA. CONCLUSION: In borderline dysplastic patients undergoing hip arthroscopic surgery with labral treatment and capsular plication, LT tears may indicate advanced instability and portend slightly inferior outcomes when compared with a match-controlled group. Borderline dysplastic patients with LT tears may have increased propensities toward revision arthroscopic surgery and conversion to THA. LT tears in these patients may warrant consideration for additional procedures including periacetabular osteotomy and LT reconstruction.

Atraumatic tears of the ligamentum teres are more frequent in professional ballet dancers than a sporting population.

OBJECTIVES: To compare the frequency of atraumatic ligamentum teres (LT) tear in professional ballet dancers with that of athletes, and to determine the relationship with clinical and imaging findings. METHODS: Forty-nine male and female professional ballet dancers (98 hips) and 49 age and sex-matched non-dancing athletes (98 hips) completed questionnaires on hip symptoms and physical activity levels, underwent hip rotation range of movement (ROM) and hypermobility testing, and 3.0-Tesla magnetic resonance imaging (3 T MRI) on both hips to detect LT tears, acetabular labral tears, and articular cartilage defects, and to measure the lateral centre edge angles (LCE). RESULTS: A higher frequency of LT tear was found in dancers (55 %) compared with athletes (22 %, P = 0.001). The frequency and severity of LT tears in dancers increased with older age (P = 0.004, P = 0.006, respectively). The Hip and Groin Outcome Score (HAGOS) pain scores or hip rotation ROM did not differ significantly among participants with normal, partial, or complete tears of LT (P > 0.01 for all). Neither the frequency of generalised joint hypermobility (P = 0.09) nor the LCE angles (P = 0.32, P = 0.16, left and right hips respectively) differed between those with and those without LT tear. In most hips, LT tear co-existed with either a labral tear or a cartilage defect, or both. CONCLUSION: The higher frequency of atraumatic LT tears in professional ballet dancers suggests that the LT might be abnormally loaded in ballet, and caution is required when evaluating MRI, as LT tears may be asymptomatic. A longitudinal study of this cohort is required to determine if LT tear predisposes the hip joint to osteoarthritis.

MR arthrography of the hip with and without leg traction: Assessing the diagnostic performance in detection of ligamentum teres lesions with arthroscopic correlation.

OBJECTIVES: To retrospectively assess the diagnostic performance of hip MR arthrography with and without traction in detecting ligamentum teres (LT) lesions with arthroscopic correlation and to evaluate the effect of traction on the imaging appearance of the LT. METHODS: 73 MR arthrograms (73 consecutive patients, mean age, 34.5 years; range, 14-55 years) obtained without and with leg traction (application of 15-23 kg, use of a supporting plate for the contralateral leg) were included. Two blinded readers independently evaluated LT lesions on MR arthrograms on separate occasions: coronal images without traction; coronal images with traction; a multiplanar traction protocol. MR findings were correlated with arthroscopic records. Sensitivity/specificity of traction and non-traction imaging was compared on coronal images with the exact McNemar test. Imaging appearance of the LT with and without traction was assessed in consensus and compared on coronal images using McNemar and McNemar-Bowker tests. (p<0.05, * corrected for type I error). RESULTS: With arthroscopy 29 (40%) LT lesions were identified in 73 patients. Sensitivity was 72%/90% (without traction/with traction; p=0.25*), specificity was 89%/77% (p=0.25*) for reader 1 in assessing coronal images and for reader 2 sensitivity was 59%/86% (p=0.044*) and specificity was 93%/82% (p=0.25*). Alterations in fiber orientation, signal intensity, surface, dimension, fiber continuity after application of traction were observed in 33/73 (45%, p=0.002*), 6/73 (8%, p=0.223), 9/73 (12%, p=0.36*), 6/73 (8%, p=0.031) respectively 9/73 (12%, p=0.003) cases. Traction-related alterations in at least one criterion were observed in 41/73 (56%) cases. CONCLUSION: Application of traction can considerably alter the imaging appearance of the LT and resulted in higher rates of true-positive and false-positive findings compared to conventional MR arthrography.

Usefulness of MR arthrography of the hip with leg traction in the evaluation of ligamentum teres injuries.

PURPOSE: To retrospectively evaluate the diagnostic accuracy of magnetic resonance (MR) arthrography of the hip with leg traction in the evaluation of ligamentum teres lesions and to evaluate whether there is increased articular distraction, possibly indicating secondary instability, in hips with ligamentum teres injuries. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained for this retrospective study. MR arthrograms of the hip with leg traction of 184 consecutive patients, including 108 men (mean age, 32.6 years; range, 19-53 years) and 76 women (mean age, 38.5 years; range, 18-56 years), who underwent hip arthroscopy were assessed for the presence of ligamentum teres lesions. The MR arthrographic findings were independently assessed by two radiologists who were blinded to the arthroscopic results. The inclusion criteria stipulated no previous surgery, arthroscopy within 1 month after MR arthrography, and availability of a detailed surgical report with ligamentum teres findings. The arthroscopy findings served as the reference standard. Sensitivity, specificity, accuracy, and K statistics for interobserver and intraobserver agreement were calculated. RESULTS: At arthroscopy, 32 ligamentum teres injuries were found. The ligamentum teres was normal in 152 (82.6%) patients and had suffered low-grade partial tears in 15 (8.1%) patients, high-grade partial tears in 10 (5.4%) patients, and complete ruptures in 7 (3.8%) patients. MR arthrography with axial traction demonstrated moderate sensitivity and high specificity for both low-grade (62/93%) and high-grade (66/96%) partial tears. Grouping low- and high-grade partial tears increased the diagnostic performance of MR arthrography, yielding a sensitivity of 87% and a specificity of 95%. For complete ligamentum teres tears, MR arthrography with leg traction demonstrated high sensitivity (92%) and specificity (98%). Articular distraction was significantly increased in patients with complete ruptures of the ligamentum teres (p = 0.001). CONCLUSION: MR arthrography with leg traction offers accurate diagnosis of ligamentum teres injuries. Patients with complete tears of the ligamentum teres exhibit increased articular distraction that may indicate secondary hip instability.