Free nerve endings in the ligamentum capitis femoris

Early Postoperative Change in Hip Rotation Angle and Factors Contributing to It for Patients Undergoing Total Hip Arthroplasty

OBJECTIVE

A possible impairment in hip proprioception after total hip arthroplasty (THA) has been an issue of concern. The aims of this study were to investigate the extent of early postoperative change in standing hip rotation angle (HRAng) in patients with osteoarthritis (OA) undergoing THA and to consider a possible mechanism behind this.

MATERIALS AND METHODS

A total of 82 hips (82 patients; 63 women and 19 men) undergoing unilateral primary THA with total capsulectomy were included. We characterized the standing HRAng and internal/external range of motion (ROM) in the prone position before THA and 2 weeks after THA. Acetabular/cup and femoral/stem anteversion, combined anteversion (CA), and leg length discrepancy were also characterized. Correlations were examined postoperatively between the HRAng and the other analyzed variables.

RESULTS

The median standing HRAng showed a significant internal shift from external to more medial position (6.3° to 1.7°) 2 weeks after THA (P<.0001). The postoperative change in standing HRAng was significantly negatively correlated with the difference between the postoperative femoral anteversion and the stem anteversion (rs=-0.429, P<.0001) and with the pre- to postoperative change in CA (rs=-0.3012, P=.0063).

CONCLUSION

This study demonstrated that the extent of the rotational shift of the distal femur toward medial direction was significantly associated with increasing stem anteversion and CA. This phenomenon can be interpreted as a compensatory mechanism for maintaining the relative positional relationship between the pelvis and the proximal femur using proprioception. Therefore, we conclude that the extracapsular/extra-articular components may be prominent determinants of joint position sense. [Orthopedics. 2024;47(3):e114-e118.].

A guide to facilitate the creation of a femoral tunnel for arthroscopic ligamentum teres reconstruction: a three-dimensional computed tomography study

The ideal femoral tunnel passing through the centre of the femoral neck targeted to the footprint of the ligamentum teres (LT) is established during the LT reconstruction surgery with the free-hand technique. We aimed to quantitatively determine the entry site and define the angular orientation of the ideal femoral tunnel with its relevance to the femoral valgus angle (FVA) and the femoral anteversion angle (FAA) to facilitate the creation of an ideal femoral tunnel during the LT reconstruction surgery. A total of 60 randomly selected CT images were obtained to reconstruct three-dimensional femur models. A virtual reamer representing the ideal femoral tunnel was placed in the femur models. The femur length, FVA, FAA, the femoral tunnel anterior angle, the femoral tunnel superior angle and the skin- and bony-entry sites were measured. The femoral tunnel angular orientation was strongly correlated with the FVA and the FAA. Mathematical formulas were defined by which entry site of the reamer and the anterior and superior angulation of the femoral tunnel could be estimated before the surgery. The mean skin-entry site was 67.3 mm distal and 0.1 mm anterior to the centre of the greater trochanter's superior border. The angular orientation of the femoral tunnel using FVA and FAA can be easily estimated using mathematical formulas before LT reconstruction surgery. The entry site and angular orientation of the femoral tunnel described in this study can be used to reduce dependency on the usage of fluoroscopy and the workload on the surgeon during the LT reconstruction surgery.

Reliability and Reproducibility of a Novel Grading System for Lesions of the Ligamentous-Fossa-Foveolar Complex in Young Patients Undergoing Open Hip Preservation Surgery

Background:

Several classification systems based on arthroscopy have been used to describe lesions of the ligamentum teres (LT) in young active patients undergoing hip-preserving surgery. Inspection of the LT and associated lesions of the adjuvant fovea capitis and acetabular fossa is limited when done arthroscopically but is much more thorough during open surgical hip dislocation. Therefore, we propose a novel grading system based on our findings during surgical dislocation comprising the full spectrum of ligamentous-fossa-foveolar complex (LFFC) lesions.

Purpose:

To determine (1) intraobserver reliability and (2) interobserver reproducibility of our new grading system.

Study Design:

Cohort study (diagnosis); Level of evidence, 3.

Methods:

We performed this validation study on 211 hips (633 images in total) with surgical hip dislocation (2013-2021). We randomly selected 5 images per grade for each LFFC item to achieve an equal representation of all grades (resulting in 75 images). The ligament, fossa, and fovea were subcategorized into normal, inflammation, degeneration, partial, and complete defects. All surgeries were performed in a standardized way by a single surgeon. The femur was disarticulated using a bone hook, the LT was inspected, documented and resected, then the fossa and fovea were documented with the femoral head in full dislocation using a 70° arthroscope. Six observers with different levels of expertise in hip-preserving surgery independently conducted the measurements twice, and intraclass correlation coefficients (ICC) were calculated to determine (1) intraobserver reliability and (2) interobserver reproducibility of the novel grading system.

Results:

For intraobserver reliability, excellent ICCs were found in both the junior and the experienced raters for grading the ligament, fossa, fovea, and total LFFC (ICCs ranged from 0.91 to 0.99 for the LFFC score). We found excellent interobserver reproducibility between raters for all items of the LFFC (all interobserver ICCs ≥ 0.76).

Conclusion:

Our new grading system for lesions of the LFFC is highly reliable and reproducible. It covers the full spectrum of damage more precisely than arthroscopic classifications do and offers a scientific basis for standardized intraoperative evaluation.

The role and clinical relevance of the ligamentum teres: long-term outcomes after hip arthroscopic surgery of cam-type femoroacetabular impingement

We aimed to compare clinical and radiologic outcomes in patients with cam-type femoroacetabular impingement (FAI), with and without a partial ligamentum teres (LT) tear, who underwent hip arthroscopy (HA) with ≥10 years of follow-up. Among the patients who underwent HA for a cam-type FAI diagnosis with a labral tear, 28 patients (28 hips) with a partial LT tear and 87 patients (99 hips) with an intact LT were assigned to Groups A and B, respectively. All patients underwent partial labral debridement and femoroplasty. Debridement and thermal shrinkage were performed for LT tears. The grade of chondral damage was measured intraoperatively. Clinical items were assessed preoperatively and at the last follow-up. Patients’ satisfaction with the surgery and changes in postoperative sports ability in those who had previously been active in sports were assessed at the last follow-up. The Tönnis grade was assessed preoperatively and at the last follow-up for radiologic evaluation. Chondral damage to the acetabular and femoral head detected intraoperatively was significantly different between the groups (P = 0.005 and P &lt; 0.001). At the last follow-up, Group A patients experienced more difficulty performing sports activities than Group B patients (P = 0.056), and significantly, more Group A patients had stopped exercising despite their active participation in sports preoperatively (P = 0.002). Regarding the Tönnis grade, significant differences were found only at the final follow-up (P = 0.020). Patients with partial LT tear showed a higher grade of chondral damage, experienced decreased exercise capacity and had significantly worsened Tönnis grades, suggesting hip osteoarthritis progression compared to those with an intact LT.

Ligamentum Teres Impingement in Valgus Impacted Femoral Neck Fracture: A Case for Hip Arthroscopy

CASE

Seven years after hip arthroscopy for cam impingement, a 47-year-old female patient suffered a valgus impacted femoral neck fracture of her left hip that was stabilized with cannulated screws. After fracture healing, she experienced persisting sharp groin pain that could be elicited in flexion/internal rotation and extension/adduction. We suspected a ligamentum teres impingement at the border of the acetabular fossa due to a post-traumatic fovea alta and performed an arthroscopic ligament resection. Symptoms completely resolved thereafter.

CONCLUSION

Valgus impacted femoral neck fractures with post-traumatic fovea alta may cause painful ligamentum teres impingement that can be treated with arthroscopic resection.

Indications and Outcomes After Ligamentum Teres Reconstruction: A Systematic Review

Purpose

To systematically review the literature to better understand the current indications for ligamentum teres reconstruction (LTR), current graft and acetabular fixation options used, patient-reported outcomes after LTR, and incidence of complications and reoperations after LTR.

Methods

A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement. All literature related to LTR published prior to July 2020 was identified. The inclusion criteria consisted of investigations reporting on human patients with pathology of the ligamentum teres who underwent LTR, including mentions of the indications, graft type, acetabular fixation method, postoperative patient-reported outcome scores, and incidence of complications and reoperations.

Results

Seven studies comprising 26 patients (28 hips) were included. The most commonly reported indication for LTR was persistent pain and instability after failed prior hip arthroscopy (68%, 19 of 28 hips). The mean postoperative modified Harris Hip Score, Non-arthritic Hip Score, and visual analog scale score all showed improvement when compared with preoperative values. A total of 2 complications occurred. Complication rates ranged from 0% to 100% in included case reports and 0% to 11% in included case series. A total of 9 reoperations were performed. Reoperation rates ranged from 0% to 100% for case reports and 18% to 100% for case series. Reoperation rates ranged from 33% to 100% in studies with patients receiving acetabular fixation using anchors versus 0% to 22% in studies performing LTR with buttons. Reoperation rates in athletic patients and patients with Ehlers-Danlos syndrome ranged from 0% to 100% and 0% to 50%, respectively.

Conclusions

The main indication for LTR was persistent hip or groin pain and instability after a prior hip arthroscopy. The short-term postoperative modified Harris Hip Score, Non-arthritic Hip Score, and visual analog scale score after LTR showed favorable outcomes. However, reoperations after LTR were not uncommon.

Level of Evidence

Level V, systematic review of Level IV and V studies.

Investigation of sensory nerve endings in pulvinar, ligamentum teres, and hip joint capsule: A prospective immunohistochemical study of 36 cases with developmental hip dysplasia

OBJECTIVE

The aim of this study was to immunohistochemically identify and characterize the presence of sensory nerve endings (SNEs) in pulvinar, ligamentum teres (LT), and hip joint capsule (HJC) of children with developmental dysplasia of the hip (DDH).

METHODS

Pulvinar, LT, and HJC specimens were obtained from 38 hips of 36 children (31 girls, five boys; mean age=49 months; age range=18-132 months) during open reduction surgery for DDH. All specimens underwent subsequent routine tissue processing (formalin fixation and paraffin embedding). To determine tissue morphology, haematoxylin and eosin staining was used. SNEs were analyzed immunohistochemically using a mouse monoclonal antibody against S-100 Beta Protein based on the classification of Freeman and Wyke including four types of SNEs including mechanoreceptors: type I Ruffini corpuscles, type II Pacini corpuscles, type III Golgi organs, and type IVa unmyelinated free nerve endings (FNEs). Additionally, children were sorted into three groups based on their age at the time of surgery: Group 1 (age <3 years; 19 hips of 18), Group 2 (age: 3-5 years; 10 hips of 10 children), and Group 3 (age >5 years; 9 hips of 8 children).

RESULTS

Although no Type I, II, or III SNEs were identified in any specimen, type IVa mechanoreceptor (FNEs) was immunohistochemically characterized in 13 (34%) pulvinar, 19 (50%) LT, and 16 (42%) HJC specimens. The total density of FNEs was 3.31±5.70)/50 mm2 (range 0-21) in pulvinar specimens, 3.18 ± 5.92)/50 mm2 (range 0-24) in HJC specimens, and 4.51±6.61/50 mm2 (range 0-22) in LT specimens. Furthermore, the operated side, gender, and the number of FNEs in specimens did not differ significantly among the age groups (p>0.05 for all), and the number of FNEs was not significantly correlated with age, gender, or the operated side (p>0.05 for all).

CONCLUSION

Evidence from this study revealed that pulvinar, LT, and HJC include only FNEs, which play a role in pain sensation, among mechanoreceptors. Surgical excision of these tissues may not cause a significant loss of sensory function in the hip joint of children with DDH.

LEVEL OF EVIDENCE

Level II, Therapeutic Study.

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.

All About the Ligamentum Teres: From Biomechanical Role to Surgical Reconstruction

Intriguing anatomists and surgeons for centuries, the exact function and biomechanical significance of the ligamentum teres (LT) remains incompletely understood. The LT, also described as the ligamentum femoris capitis, is an intra-articular extrasynovial ligament extending from the cotyloid fossa of the acetabulum to the fovea on the femoral head. Some studies have described it as a vestigial structure in the adult hip. More recent biomechanical studies, however, along with histological and anatomical studies, have suggested the LT to have an important function in proprioception, nociception, and as a secondary stabilizer of the hip joint. The advent and increased utilization of hip arthroscopy to treat hip pathology over the past two decades has ignited a renewed interest in the role of the LT, as well as techniques and indications for management of pathology. In the constellation of intra-articular pain generators of the hip, LT injuries have historically been difficult to diagnose through physical examination or advanced imaging. Numerous classification systems have been proposed based on arthroscopic appearance, and for most cases, conservative management is adequate. In patients undergoing hip arthroscopy, LT débridement usually suffices, although in cases of persistent pain and severe instability, reconstruction of the ligament may be indicated. Multiple methods for reconstruction have been described, with the greatest variation in the method of acetabular fixation of the graft. Future research should focus on clarifying the role of the LT, appropriate surgical indications for reconstruction, and optimization of graft fixation within the acetabulum.

Innervation of the hip joint capsular complex: A systematic review of histological and immunohistochemical studies and their clinical implications for contemporary treatment strategies in total hip arthroplasty

The hip joint capsule contributes to the stability of the hip joint and lower extremity, yet this structure is incised and often removed during total hip arthroplasty (THA). Increasing incidence of osteoarthritis is accompanied by a dramatic rise in THAs over the last few decades. Consequently, to improve this treatment, THA with capsular repair has evolved. This partial restoration of physiological hip stability has resulted in a substantial reduction in post-operative dislocation rates compared to conventional THA without capsular repair. A further reason for the success of this procedure is thought to be the preservation of the innervation of the capsule. A systematic review of studies investigating the innervation of the hip joint capsular complex and pseudocapsule with histological techniques was performed, as this is not well established. The literature was sought from databases Amed, Embase and Medline via OVID, PubMed, ScienceDirect, Scopus and Web of Science; excluding articles without a histological component and those involving animals. A total of 21 articles on the topic were identified. The literature indicates two primary outcomes and potential clinical implications of the innervation of the capsule. Firstly, a role in the mechanics of the hip joint, as mechanoreceptors may be present in the capsule. However, the nomenclature used to describe the distribution of the innervation is inconsistent. Furthermore, the current literature is unable to reliably confirm the proprioceptive role of the capsule, as no immunohistochemical study to date has reported type I-III mechanoreceptors in the capsule. Secondly, the capsule may play a role in pain perception, as the density of innervation appears to be altered in painful individuals. Also, increasing age may indicate requirements for different strategies to surgically manage the hip capsule. However, this requires further study, as well as the role of innervation according to sex, specific pathology and other morphometric variables. Increased understanding may highlight the requirement for capsular repair following THA, how this technique may be developed and the contribution of the capsule to joint function and stability.

Ligamentum teres reconstruction: indications, technique and minimum 1-year results in nine patients

Ligamentum teres (LT) tear is a recognized cause of hip pain. Debridement of tears and capsule plication has shown satisfactory results. However, a group of patients with complete tears do not improve after debridement and physiotherapy. The purpose of this work was to describe the senior author's technique and clinical results for the early series of LT reconstructions. Retrospective analysis of prospectively collected data. Patients who underwent isolated LT reconstruction between 2013 and 2018. All the patients had previous debridement of a completely torn LT, capsule plication and rehabilitation. Patients who had any other associated procedure during LT reconstruction surgery and dysplastic acetabular features were excluded. Demographic and clinical data was reviewed. Complications, type of graft and modified Harris hip scores (mHHSs) were recorded preoperatively and at 1-year follow-up. Fifteen LT reconstructions were performed during the study period. Six were excluded (as they had additional procedures performed during surgery) and nine patients aged a mean 30 (range: 22-48) years old were included. The patients had a mean of 2 (range: 1-4) prior surgeries. At minimum 12 months (range: 12-24) 9/9 patients reported reduction of pain and instability symptoms with mHHSs of 84.2 (73.7-100) versus 51.7 (36.3-70.4) preoperatively (P = 0.00094). Three patients (of the total cohort of 15) underwent second-look arthroscopy (11-22 months after reconstruction). None of these patients underwent total hip replacement at a mean of 4 (range: 1-6) years. Arthroscopic LT reconstruction improved function and pain in patients with persistent pain and instability after resection of the LT.

Load-deformation properties of the ligament of the head of femur in situ

The ligament of the head of femur (LHF) or ligamentum teres has been reported to tense during hip adduction and also to provide mechanical stability to the joint. LHF injury is more common in females and also in right hip joints compared with left ones. Although this could be due to leg dominance, pelvic size or muscle strength, there is no study that has looked into these differences. This cadaveric biomechanical study aimed to compare potential differences in the mechanical behavior of the LHF between neutral and 20° adducted hip joints, sex, and sides. Tensile tests of the LHF were performed on 25 hip joints (mean age at death of 85.7 ± 7.5 years; 9 females, 4 males; 13 left, 12 right), positioned either neutrally or in adduction. The maximum force required to rupture the ligament, its strain at failure, tensile strength, linear stiffness, and elastic modulus were obtained and statistically compared between analysis groups. The maximum force the LHF could withstand before rupture averaged 57 ± 37 N, strain at failure of 59 ± 33%, tensile strength of 2.9 ± 1.8 MPa, linear stiffness of 5.4 ± 3.5 N/mm, and elastic modulus of 7.2 ± 3.8 MPa. The LHF length at failure was significantly greater in males compared with females (P = 0.02). Irrespective of joint position, there were no statistical differences in the stress-strain properties of the LHF between females and males, or sides. There may be other anatomical, functional, and demographic factors that could render the ligament tissue vulnerable to injury in these groups. Clin. Anat., 33:705-713, 2020. © 2019 Wiley Periodicals, Inc.

Neurovascular structures of the ligament of the head of femur

The ligament of the head of femur (LHF), or ligamentum teres, is believed to provide blood supply to the head of femur and mechanical stability to the hip joint. But these functions in the adult are often debated. The existence and distribution of neurovascular structures within the ligament are not widely documented. This study examined the blood vessels and nervous tissue within the LHF to determine whether the ligament may have a vascular and proprioceptive function at the hip joint. Histological sections from the LHF from 10 embalmed hips (six female, four male; mean age 80.4 ± 8.7 years) were cut at three levels: the foveal attachment, mid-length and its base where it attaches to the transverse acetabular ligament. Sections were stained with haematoxylin and eosin to study general tissue architecture or with von Willebrand factor and neurofilament to identify blood vessels and nervous tissue, respectively. The proportion of the ligament's cross-sectional area occupied by blood vessels was expressed as a vascularity index (VI). Nerve endings within the ligament were identified and morphologically classified. Comparisons between the VI at the three levels, or between the tissue layers of the ligament, were made using 95% confidence intervals; statistical significance was set P < 0.05. The ligament tissue comprised three distinct layers: a synovial lining with cuboidal cells, a sub-synovial zone formed of loose connective tissue and the ligament proper composed of dense collagen bundles. Patent blood vessels and nerve fibres were present both in the sub-synovial zone and the ligament proper; Pacinian corpuscles and free nerve endings were found scattered only in the sub-synovial zone. The VI of the ligament proper at the fovea was significantly higher than its middle (P = 0.01) and basal levels (P = 0.04); it was also higher than that of the sub-synovial layer (P = 0.04). The LHF has three histologically distinct zones, and blood vessels and nerves are distributed both in the sub-synovial layer and ligament proper. Higher vascularity within the ligament proper at its foveal insertion suggests a possible nutritive role of the LHF to the adult head of femur. The presence of nerves and nerve receptors indicates the ligament is involved in the perception of pain and proprioception, thereby contributing to mechanical stability of the joint.

Partial ligamentum teres tears are associated with larger acetabular labra and less damage to the labrum than complete ligamentum teres tears

The purpose of this study was to investigate the association between ligamentum teres (LT) tears with hypertrophy of the acetabular labrum and cartilage and labral damage. Surgeries (1723) were performed from February 2010 to March 2016 with arthroscopic measurement of the labrum and assessment of the LT, labrum and acetabular cartilage. Labral width was measured in the anterosuperior (AS), anteroinferior (AI), posteroinferior (PI) and posterosuperior (PS) quadrants. Grade 2 (50-99% torn) LT tears had larger labra in all four quadrants (AS = 5.64 ± 1.97 mm; AI = 5.23 ± 1.51; PS = 5.58 ± 1.39; PI = 4.60 ± 1.13) than grade 3 (100% torn) (AS = 5.50 ± 1.94; AI 4.90 ± 1.43; PS 5.43 ± 1.32; PI 4.42 ± 1.03), grade 1 (<50% torn) (AS 5.30 ± 1.68; AI 4.96 ± 1.32; PS = 5.38 ± 1.13; PI = 4.45 ± 1.04) and no tear (AS = 5.09 ± 1.51; AI = 4.92 ± 1.24; PS = 5.24 ± 1.09; PI = 4.37 ± .93); P < 0.01 in all quadrants. Grade 3 LT tears had more damage to the labrum than grade 2, grade 1 and no tear; P < 0.001. ALAD tears were larger in grade 3 and grade 2 than grade 1 and non-torn LTs; P < 0.001. Grade 3 tears had a higher percentage of high-grade cartilage tears than grade 2 LT tears; P < 0.001. Degenerative tears had larger labra, labral tears and acetabular cartilage tears than full- and partial-thickness LT tears; P < 0.01. Patients with partial-thickness LT tears had larger labra in all four quadrants than full-thickness tears in the Percentile and Villar classifications. Full-thickness tears had more severe labral damage and higher-grade chondral damage than partial-thickness tears. Degenerative tears demonstrated the largest labra, labral tears and ALAD tears. The condition of the LT demonstrated an association with acetabular cartilage injury and should be evaluated when considering hip preservation surgery. LEVEL OF EVIDENCE: Level IV Case Series.

Cranial cruciate ligament structure in relation to the tibial plateau slope and intercondylar notch width in dogs

Cranial cruciate ligament (CCL) rupture is one of the most common orthopedic conditions in dogs. The pathogenesis of CCL rupture is not fully described and remains to be elucidated fully. Several hypotheses have been proposed to explain the etiology of these changes. The objective of this study was to investigate structural changes in the CCL in relation to the tibial plateau angle (TPA) and the intercondylar notch (ICN) width in dogs. Fifty-five skeletally mature dogs were included in this study. ICN width and TPA measurements were obtained from intact CCL stifles. Samples of the CCL, caudal cruciate ligament (CaCL), and femoral head ligament (FHL) were harvested and stained for routine histological and immunohistochemical analysis. Microscopic changes in the ligaments were observed and were found to correlate with the TPA and ICN width values. The degree of structural changes within the CCL was observed to correlate with an increasing TPA and a narrowing ICN width. Changes in the CCL are likely to be caused by excessive forces acting through the ligament in stifles with a high TPA. Chondroid metaplasia of the CCL is an adaptation to abnormal mechanics within the stifle joint caused by altered bone morphology.

Primary Synovial Osteochondromatosis of the Hip Joint Treated with Arthroscopic-assisted Mini-open Surgery-Two Case Reports

Introduction:

Primary synovial osteochondromatosis of the hip joint is a rare condition. It is characterized by the presence of multiple intra-articular loose bodies and can result in mechanical symptoms, even causing degenerative change. Surgical treatment is indicated for synovial osteochondromatosis of the hip joint. However, the optimal approaches for successful surgical management are still controversial.

Case Report:

We report two cases with primary synovial osteochondromatosis of the hip joint where arthroscopic-assisted mini-open surgical treatmentwas performed. The posterior approach was used, and a minimal arthrotomy was performed with preservation of bloody supplement of thefemoral head. With the assistance of an arthroscope, synovectomy, debridement, and loose body removal were completed without dislocating the femoral head. The follow-up duration was 5years and 2.5 years, respectively. There were no perioperative or post-operative complications. At the latest follow-up, the patients remain symptom free with no radiographic evidence of recurrence.

Conclusions:

Our arthroscopic-assisted mini-open method could achieve the goals of extensive synovectomy, debridement, and loose body removal, thus reducing the recurrence rate. This method avoids dislocation of the femoral head, thus reducing the occurrence of surgical complications.

The ligamentum teres femoris in orangutans

OBJECTIVES

It is widely viewed that orangutans lack a ligamentum teres femoris (LTF) inserting on the femoral head because orangutans lack a distinct fovea capitis. Orangutans employ acrobatic quadrumanous clambering that requires a high level of hip joint mobility, and the absence of an LTF is believed to be an adaptation to increase hip mobility. However, there are conflicting reports in the literature about whether there may be a different LTF configuration in orangutans, perhaps with a ligament inserting on the femoral neck instead. Here we perform a dissection-based study of orangutan hip joints, assess the soft tissue and hard tissue correlates of the orangutan LTF, and histologically examination the LTF to evaluate whether it is homologous to that found in other hominoids.

MATERIALS AND METHODS

The hip joints from six orangutans were dissected. In the two orangutans with an LTF passing to the femoral head, the LTF was assessed histologically. Skeletonized femora (n=56) in osteological repositories were examined for evidence of a foveal pit.

RESULTS

We observed an LTF in two of the three infant orangutans but not in the sub-adult or adult specimens. Histological examination of the infant LTF shows a distinct artery coursing through the LTF to the head of the femur. One percent of orangutan femora present with a foveal scar, but no pit, on the femoral head.

DISCUSSION

Despite being absent in adults, the LTF is present in at least some orangutans during infancy. We suggest that the LTF maintains a role in blood supply to the femoral head early in life. Because the LTF can limit hip mobility, this may explain why the LTF may be lost as an orangutan ages and gains locomotor independence. These findings enhance our understanding of orangutan hip morphology and underscore the need for future soft tissue investigations.

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.

Simultaneous acetabular labrum and ligamentum teres reconstruction: a case report

This study aims to present the surgical technique for reconstructing both the acetabular labrum and the ligamentum teres and to describe the early outcomes of this procedure in a 15-year-old male with recurrent hip instability. A 15-year-old patient with recurrent left hip dislocation, hip joint instability and failed non-operative intervention presented following two left hip dislocations. A labral reconstruction was performed utilizing an iliotibial band allograft tissue with a concomitant ligamentum teres reconstruction using a tibialis anterior allograft. The patient was assessed pre- and postoperatively using modified Harris Hip Score, Lower Extremity Functional Scale and Visual Analogue Scale for pain and satisfaction. The patient reported improvement on all measures, including hip stability 14 months following surgery. The patient has not reported any episodes or subjective feelings of instability, has not required further surgical procedures in the hip and has returned to full sports participation. This case report demonstrates a technique for and early outcomes of simultaneous arthroscopic ligamentum teres and acetabular labrum reconstruction in a patient with recurrent hip instability. Short-term outcomes suggest improved hip stability, reduced pain, high patient satisfaction and return to pre-injury activities at 14 months postoperative in this single case report.

The role of the ligamentum teres in the adult hip: redundant or relevant? A review

The ligamentum teres (LT) has traditionally been described as a redundant structure with no contribution to hip biomechanics or function. There has been renewed interest in the LT as a source of hip pathology due to the high prevalence of LT pathology observed at the time of hip arthroscopy. The LT acts a secondary stabilizer to supplement the work of the capsular ligaments and works in a sling-like manner to prevent subluxation of the hip at the extremes of motion. The presence of free nerve endings within the LT indicates a definite role in pain generation, with the LT undergoing various mechanical and histological adaptations to hip pathology.

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.

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.

Comprehensive Review of Advancements in Hip Arthroscopy

Hip arthroscopy is currently being leveraged in the diagnosis and treatment of a wide range of hip joint problems. In fact, great advancements in hip arthroscopy have resulted in an ever-expanding number of indications to which it is being applied. Minimally invasive hip arthroscopy allows for quicker initiation of rehabilitation and has attracted much attention as the field becomes increasingly focused on surgeries designed to preserve joints. This review aims to summarize the recent advances, applications, and impact of hip arthroscopy.

The reliability of commonly used arthroscopic classifications of ligamentum teres pathology

The importance of the ligamentum teres (LT) in the hip is increasingly being recognized. However, the incidence of LT tears in the literature is extremely variable. Although classification systems exist their reliability in classifying LT pathology arthroscopically has not been well defined. To determine the inter- and intra-observer reliability of two existing classifications systems for the diagnosis of LT pathology at hip arthroscopy. Second, to identify key pathological findings currently not included. Four experienced hip-arthroscopists reviewed 40 standardized arthroscopic videos. Arthroscopic findings of the LT were classified using the Gray and Villar (G&V) and descriptive classification (DC). Reviewers were asked to record other relevant pathology encountered. Inter- and intra-observer reliability was defined using Fleiss-Kappa and Cohen-Kappa statistics. Both classifications demonstrated fair inter-observer reliability. The intra-observer reliability for G&V was moderate-to-substantial and for DC was slight-to-moderate. An absolute agreement rate of 10% (G&V) and 37.5% (DC) was found. Differentiation between normal, and partial or low-grade tears was a common source of disagreement. The prevalence of LT pathology was 90%. Synovitis was the most common diagnostic finding that was not included in either classification system used in this study. Arthroscopic classification of LT pathology using the G&V and the DC demonstrated only fair inter-observer reliability. The major discrepancy in interpretation was between normal, and partial or low-grade tears. The presence of synovitis was not in either classification but was considered an important arthroscopic finding. Thorough arthroscopic scrutiny reveals the prevalence of LT pathology is higher than previously reported.

Tensile properties of the hip joint ligaments are largely variable and age-dependent - An in-vitro analysis in an age range of 14-93 years

INTRODUCTION

Hip joint stability is maintained by the surrounding ligaments, muscles, and the atmospheric pressure exerted via these structures. It is unclear whether the ligaments are capable of preventing dislocation solely due to their tensile properties, and to what extent they undergo age-related changes. This study aimed to obtain stress-strain data of the hip ligaments over a large age range.

METHODS

Stress-strain data of the iliofemoral (IL), ischiofemoral (IS) and pubofemoral ligament (PF) were obtained from cadavers ranging between 14 and 93 years using a highly standardized setting. Maximum strains were compared to the distances required for dislocation.

RESULTS

Elastic modulus was 24.4 (IL), 22.4 (IS) and 24.9N/mm² (PF) respectively. Maximum strain was 84.5%, 86.1%, 72.4% and ultimate stress 10.0, 7.7 and 6.5N/mm² for the IL, IS and PF respectively. None of these values varied significantly between ligaments or sides. The IS' elastic modulus was higher and maximum strain lower in males. Lower elastic moduli of the PF and higher maximum strains for the IS and PF were revealed in the ≥55 compared to the <55 population. Maximum strain exceeded the dislocation distance of the IS without external hip joint rotation in females, and of the IS and cranial IL under external rotation in both genders.

DISCUSSION

Tensile and failure load properties of the hip joint ligaments are largely variable. The IS and PF change age-dependently. Though the hip ligaments contribute to hip stability, the IS and cranial IL may not prevent dislocation due to their elasticity.

Ligamentum Teres Tears and Femoroacetabular Impingement: Prevalence and Preoperative Findings

PURPOSE

To determine prevalence of ligamentum teres (LT) injuries identified during hip arthroscopy for treatment of femoroacetabular impingement (FAI) and to identify physical examination findings or radiographic characteristics specific to patients with complete LT tears that could possibly assist in a preoperative diagnosis.

METHODS

Between October 2006 and June 2015, prospective data were collected on consecutive hip arthroscopies. Inclusion criterion was primary hip arthroscopy in patients aged 18 years or older. All patients in the study were treated for chondrolabral dysfunction associated with FAI. Patients with prior hip surgery were excluded. A total of 2,213 out of 3,158 hip arthroscopies met the inclusion criterion.

RESULTS

Of the 2,213 hips, 233 (11%) had a normal LT, 1,947 (88%) had frayed/partially torn, and 33 (1.5%) had a torn LT. A higher prevalence of torn LT was seen in female subjects. Patients with torn LT had lower body mass index (BMI) (22.5 v 24.7; P < .01) than those with hips with normal LT. On radiographs, patients with torn LTs had a lower center edge angle and had increased odds of having a center edge angle less than 25°. Isolated cam or isolated pincer were seen more often in hips with torn LT than in hips with normal LT. Hips with torn LT were 3.1 times more likely to have a chondral defect on the femoral head than were hips with normal LT (95% confidence interval [CI], 1.2-8.7) and were 3.6 times more likely to have capsular laxity diagnosed at hip arthroscopy than were hips with normal LT (95% CI, 1.4-9.4).

CONCLUSIONS

Among patients with FAI and labral pathology, complete tears of the LT were rare and were more likely to be seen in women and those with lower BMI and low center edge angles at arthroscopy. LT tears were associated with hip laxity and chondral defects of the femoral head.

LEVEL OF EVIDENCE

Level IV, prognostic case series.

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.

NERVE ENDINGS AND VASCULAR SUPPLY IN SEMITENDINOSUS TENDON OF CEREBRAL PALSY CHILDREN

Objective: To evaluate the distribution of SP (substance P) and S-100 peptide immunoreactivity, as well as the vascular supply of tissues commonly used as grafts for anterior cruciate ligament (ACL) reconstruction. A second aim was to compare the above mentioned distribution in the semitendinosus muscle tendons of cerebral palsy (CP) patients with the semitendinosus muscle tendons and patellar tendons of patients without CP. Methods: The first group consisted of 14 children with cerebral palsy with a mean age of 11.7 years old. At the time of hamstring lengthening operation, a sample of semitendinosus muscle was taken for analysis. The second group comprised 20 patients treated for isolated ACL rupture of the knee (mean age 32 years old). Group three comprised ten patients in the mean age of 14.3 years old treated for recurrent lateral patellar dislocation, and from whom a sample of patellar tendon was obtained. Results: No statistically significant differences were demonstrated with regard to the amount of immunopositive nerve fibers expressing SP or S-100 in all 3 groups of patients. A significant difference was noted in the number of blood vessels between the adult and child semitendinosus muscles, but not between the semitendinosus muscles and patellar tendon of children. Conclusion: The number of nociceptors as well as proprioceptive fibers is similar in patients with CP and patients from a neurologically healthy population. Level of Evidence IV, Cases Series.

Magnetic Resonance Imaging of the Hip

Hip pain is common in all age groups, and osteoarthritis of this joint is an increasingly recognized problem particularly in aging populations. One of the primary goals in the diagnostic evaluation in patients with hip pain is to identify and correct pathologies that could progress to osteoarthritis. Magnetic resonance imaging (MRI) has become an important noninvasive method for characterizing hip anatomy and pathology in these patients. Improvements in MRI hardware and techniques have allowed high spatial and contrast resolution imaging to detect subtle abnormalities, such as acetabular labral and articular cartilage injuries, which often contribute to patient symptoms. Newer MRI techniques, such as delayed gadolinium-enhanced MRI of cartilage and T2 mapping, can give insight into the biochemical structure of tissues such as the articular cartilage. In turn, these can allow quantitative assessment and enable imagers to more directly compare the findings of patients at earlier stages of disease. It is important to understand the fundamental principles of various MRI techniques and their limitations to know when these techniques can best be applied. In addition, understanding of normal hip anatomy and common anatomic variants is useful for being able to accurately detect and localize areas of pathology and to prevent misinterpreting normal structures as diseased. The aims of this work were to briefly review normal hip anatomy and common anatomic variants seen on routine MRI examination, to discuss principles often used in high-resolution hip MRI and newer techniques for biochemical evaluation, and to examine several intra-articular pathologic conditions of the hip joint that are of current clinical interest.

Ligamentum teres injuries - an observational study of a proposed new arthroscopic classification

Ligamentum teres (LT) Injuries or tears have been said to be a common cause of groin discomfort and pain, and they have been identified in 8–51% of patients undergoing hip arthroscopy. Currently, in the literature there exist three arthroscopic classifications for LT injuries and tears: the first classification was established by Gray and Villar, Botser and Domb proposed the second one which they called a descriptive classification according to the degree of partial thickness LT tears and more recently the last classification by Cerezal et al. (RadioGraphics 2010; 30:1637–51), where they take into account the one by Gray and Villar but adding an avulsion fracture and absence of the LT. We propose a new classification, which also takes into account, observed LT pathologies, as well as the possible pathological mechanism of LT tears, and offer a guide to treatment. This classification is based on direct arthroscopic observation and dynamic rotational maneuvers of the hip under distraction. This classification incorporates those pathologies, which have been observed as a result of this more focused examination of the LT.

Comparison of mechanoreceptor quantities in hip joints of developmental dysplasia of the hip patients with normal hips

BACKGROUND

Joint mechanoreceptors are afferent neural elements involved in pain sensation and tactile sense.

QUESTIONS/PURPOSES

We aimed to detect the free nerve endings (FNE) and other types of mechanoreceptors and to compare their quantities in human hip joint capsule (HJC) and ligamentum capitis femoris (LCF) of babies with developmantal dysplasia of hip (DDH) and intrauterine ex foetuses (control group) to find out whether there is an increase in the amount of mechanoreceptors in hip joint due to the occured anatomical chages.

PATIENTS AND METHODS

We took 15 LCF and HJC biopsies from 15 patients undergoing hip surgery for DDH, and 15 HJC and LCFs from intrauterine ex fetuses. Total of 60 specimens were investigated. The mean age of the babies was 10.3 months (6-18 months) at the time of surgery. Full thickness 1 × 1 cm HJC and LCF portions were taken as biopsy specimens. An immunohistochemical technique was performed for neurogenic protein S-100 and examined under light microscopy.

RESULTS

FNEs were detected in all four different tissues (type IVa). Other types of mechanoreceptors (Type I-II and III) were not detected in any of the specimens. The positive rates of FNE staining in the control group were % 2.60 ± 1.24 for the LCF and % 2.67 ± 1.11 for the HJC respectively and FNE staining in the DDH group were found to be % 2.67 ± 1.11 for the LCF and % 2.73 ± 1.16 for the HJC. We did not find a statistically significant difference in number of FNEs between the specimens of the DDH group and the control group (p>0.05), also there was no statistically significant difference in number of FNEs between the HJC and LCF within each group (p>0.05).

CONCLUSION

Our results suggest that the number of FNEs does not increase in HJC and LCF of DDH patients even though LCF hypertrophy and capsular elongation occurs.

Structural Properties of the Native Ligamentum Teres

Background:

A majority of studies investigating the role of the ligamentum teres (LT) have focused primarily on anatomical and histological descriptions. To date, however, the structural properties of the LT have yet to be fully elucidated.

Purpose:

To investigate the structural properties of the native LT in a human cadaveric model.

Study Design:

Descriptive laboratory study.

Methods:

A total of 12 human cadaveric hemipelvises (mean age, 53.6 years; range, 34-63 years) were dissected free of all extra-articular soft tissues to isolate the LT and its acetabular and femoral attachments. A dynamic tensile testing machine distracted each femur in line with the fibers of the LT at a displacement-controlled rate of 0.5 mm/s. The anatomic dimensions, structural properties, and modes of failure were recorded.

Results:

The LT achieved a mean yield load of 75 N and ultimate failure load of 204 N. The LT had mean lengths of 38.0 and 53.0 mm at its yield and failure points, respectively. The most common (75% of specimens) mechanism of failure was tearing at the fovea capitis. On average, the LT had a linear stiffness of 16 N/mm and elastic modulus of 9.24 MPa. The mean initial length and cross-sectional area were 32 mm and 59 mm², respectively.

Conclusion:

The human LT had a mean ultimate failure load of 204 N. Therefore, the results of this investigation, combined with recent biomechanical and outcomes studies, suggest that special consideration should be given to preserving the structural and corresponding biomechanical integrity of the LT during surgical intervention.

Clinical Relevance:

The LT may be more important as a static stabilizer of the hip joint than previously recognized. Further studies are recommended to investigate the appropriate indications to perform surgical repair or reconstruction of the LT for preservation of hip stability and function.

Function of the ligamentum teres in limiting hip rotation: a cadaveric study

PURPOSE

The purpose of this cadaveric study was to evaluate the function of the ligamentum teres (LT) in limiting hip rotation in 18 distinct hip positions while preserving the capsular ligaments.

METHODS

Twelve hips in 6 fresh-frozen pelvis-to-toes cadaveric specimens were skeletonized from the lumbar spine to the distal femur, preserving only the hip ligaments. Hip joints were arthroscopically accessed through a portal located between the pubofemoral and iliofemoral ligaments to confirm the integrity of the LT. Three independent measurements of hip internal and external rotation range of motion (ROM) were performed in 18 defined hip positions of combined extension-flexion and abduction-adduction. The LT was then arthroscopically sectioned and rotation ROM reassessed in the same positions. A paired sample t test was used to compare the average internal and external hip rotation ROM values in the intact LT versus resected conditions in each of the 18 positions. P < .0014 was considered significant.

RESULTS

A statistically significant influence of the LT on internal or external rotation was found in 8 of the 18 hip positions tested (P < .0014). The major increases in internal and external rotation ROM occurred when the hip was in 90° or 120° of flexion.

CONCLUSIONS

The major function of the LT is controlling hip rotation. The LT functions as an end-range stabilizer to hip rotation dominantly at 90° or greater of hip flexion, confirming its contribution to hip stability.

CLINICAL RELEVANCE

Ruptures of the LT contribute to hip instability dominantly in flexed hip positions.

The ligamentum teres-its increasing importance

The ligamentum teres (LT) has attracted much greater interest over recent years due to the increased use of hip arthroscopy. There have been advancements in our understanding of the LT's biomechanical function and its role in hip and groin pain. Our ability to suspect LT tears by clinical examination and imaging has improved. Publications by many authors concerning LT tear treatment and outcomes continue to increase. This manuscript is a review of the function, mechanism of injury, clinical assessment, imaging, arthroscopic assessment, treatment, outcomes, reconstruction, and unusual conditions of the LT.

Phenomenon of painless knee in recurrent patellar dislocation in children

INTRODUCTION

Cartilage lesion with patellar malalignment may be correlated with pain. Situations in which patients with recurrent patellar dislocation are painless between episodes of luxation can be approached with considerable curiosity. We evaluated the distribution of substance-P and S-100 protein expression in soft tissue of the knee in children with recurrent patellar dislocation, in order to evaluate the distribution of nociceptors and determine tissue origins of this situation.

MATERIAL AND METHODS

Samples were collected from the medial and lateral synovial membrane, medial and lateral patellar retinaculum, Hoffa's body, patellar ligament, and quadriceps' aponeurosis in 10 children during the Blauth procedure and 10 adults with idiopathic osteoarthritis during total joint alloplasty. The density of nociceptive fibres was compared in the children and adults using S-100 and substance-P monoclonal antibodies.

RESULTS

Statistical differences between groups were demonstrated for S-100 expression in synovial membrane of the medial knee compartment (p < 0.05) and for substance-P expression in the medial patellar retinaculum (p < 0.05) and synovial membrane of the lateral (p < 0.05) and medial (p < 0.05) knee compartment in favour of children.

CONCLUSIONS

Lack of pain sensations in patients with recurrent patellar dislocation may be associated with non-increased expression of nerve endings in Hoffa's body. Increased expression of either S-100 protein or substance-P in synovial membrane and the medial retinaculum did not induce pain development in the knee joints of that group of patients.

Preoperative diagnosis of pathologic conditions of the ligamentum teres: is MRI a valuable imaging modality?

PURPOSE

The purpose of this study was to determine the accuracy of 3-Tesla magnetic resonance imaging (MRI) in detecting ligamentum teres (LT) lesions in patients before they undergo hip arthroscopy for the treatment of femoroacetabular impingement.

METHODS

From 2010 to 2011, data were prospectively collected on all patients presenting for treatment of hip pain. All patients underwent MRI followed by arthroscopic surgery. A radiologist prospectively documented MRI findings, and the surgeon recorded the findings at arthroscopy. Radiologic and surgical data included classification of the LT as not torn, hypertrophic, partially torn, or completely torn. All MR images were read by a single radiologist, and all surgery was performed by a single surgeon. Arthroscopy was considered the diagnostic gold standard.

RESULTS

One hundred forty-two patients with a mean patient age of 35 years (range, 19 to 73 years) met the inclusion criteria. Only one complete LT tear was found in the study. The accuracy of MRI for the diagnosis of LT partial tears was 64%. The sensitivity and specificity of MRI for diagnosing partial tears of the LT were 9% and 91%, [corrected] respectively. The positive predictive value and negative predictive value were 31% and 67%, [corrected] respectively. The sensitivity and specificity of MRI for diagnosing hypertrophic LT were 32% and 78%, respectively.

CONCLUSIONS

In this patient population, MRI demonstrated sensitivity and specificity of 34% and 50%, [corrected] respectively, in identifying any pathologic process of the LT. MRI is capable of ruling out [corrected] partial tears of the LT with high sensitivity (91%) and negative [corrected] predictive value (67%).

LEVEL OF EVIDENCE

Level II, development of diagnostic criteria on basis of consecutive patients with universally applied gold standard.

Hip joint pain in children with cerebral palsy and developmental dysplasia of the hip: why are the differences so huge?

BACKGROUNDS

Non-traumatic hip dislocation in children is most often observed in the course of developmental dysplasia of the hip (DDH) and infantile cerebral palsy. The risk of pain sensations from dislocated hip joint differentiates the discussed groups of patients. Will every painless hip joint in children with cerebral palsy painful in the future?

METHODS

Material included 34 samples of joint capsule and 34 femoral head ligaments, collected during open hip joint reduction from 19 children with CP, GMFCS level V and from 15 children with DDH and unilateral hip dislocation. All the children were surgically treated.The density of nociceptive fibres was compared between the children with CP and DDH, using S-100 and substance P monoclonal antibodies.

RESULTS

More frequent positive immunohistochemical reaction to S-100 protein concerned structures of the femoral head ligaments in children with CP and cartilage losses on the femoral head, when compared to the same structures in children with DDH (p = 0.010). More frequent were found positive immunohistochemical reactions for S-100 protein in the joint capsules of children with cartilage losses (p = 0.031) and pain ailments vs. the children with DDH (p = 0.027). More frequent positive reaction to substance P concerned in femoral head ligaments in CP children and cartilage lesions (p = 0.002) or with pain ailments (p = 0.001) vs. the DDH children.

CONCLUSIONS

Surgical treatment of hip joint dislocation should be regarded as a prophylactics of pain sensations, induced by tissue sensitisation, inflammatory process development or articular cartilage defects.

A novel technique for ligamentum teres reconstruction with "all-suture" anchors in the medial acetabular wall

The function of the ligamentum teres remains poorly understood, but tears have been recognized as a source of hip pain. In some patients with complete ligamentum teres tears, symptoms of instability are described. Microinstability and excess motion are hypothesized to be a source of pain and mechanical symptoms. Efforts in recent years to improve symptoms have led to the development of techniques used to reconstruct the ligamentum teres, with some early evidence that reconstruction can improve symptoms in appropriately selected patients. We describe our technique for ligamentum teres allograft reconstruction using anchors made only of suture seated in the acetabular floor.

In vivo baseline measurements of hip joint range of motion in suspensory and nonsuspensory anthropoids

Hominoids and atelines are known to use suspensory behaviors and are assumed to possess greater hip joint mobility than nonsuspensory monkeys, particularly for range of abduction. This assumption has greatly influenced how extant and fossil primate hip joint morphology has been interpreted, despite the fact that there are no data available on hip mobility in hominoids or Ateles. This study uses in vivo measurements to test the hypothesis that suspensory anthropoids have significantly greater ranges of hip joint mobility than nonsuspensory anthropoids. Passive hip joint mobility was measured on a large sample of anesthetized captive anthropoids (nonhuman hominids = 43, hylobatids = 6, cercopithecids = 43, Ateles = 6, and Cebus = 6). Angular and linear data were collected using goniometers and tape measures. Range of motion (ROM) data were analyzed for significant differences by locomotor group using ANOVA and phylogenetic regression. The data demonstrate that suspensory anthropoids are capable of significantly greater hip abduction and external rotation. Degree of flexion and internal rotation were not larger in the suspensory primates, indicating that suspension is not associated with a global increase in hip mobility. Future work should consider the role of external rotation in abduction ability, how the physical position of the distal limb segments are influenced by differences in ROM proximally, as well as focus on bony and soft tissue differences that enable or restrict abduction and external rotation at the anthropoid hip joint.

The distribution of nociceptive innervation in the painful hip

Our understanding of the origin of hip pain in degenerative disorders of the hip, including primary osteoarthritis, avascular necrosis and femoroacetabular impingement (FAI), is limited. We undertook a histological investigation of the nociceptive innervation of the acetabular labrum, ligamentum teres and capsule of the hip, in order to prove pain- and proprioceptive-associated marker expression. These structures were isolated from 57 patients who had undergone elective hip surgery (44 labral samples, 33 ligamentum teres specimens, 34 capsular samples; in 19 patients all three structures were harvested). A total of 15 000 histological sections were prepared that were investigated immunohistochemically for the presence of protein S-100, 68 kDa neurofilament, neuropeptide Y, nociceptin and substance P. The tissues were evaluated in six representative areas.

Within the labrum, pain-associated free nerve ending expression was located predominantly at its base, decreasing in the periphery. In contrast, the distribution within the ligamentum teres showed a high local concentration in the centre. The hip capsule had an almost homogeneous marker expression in all investigated areas.

This study showed characteristic distribution profiles of nociceptive and pain-related nerve fibres, which may help in understanding the origin of hip pain.

Cite this article: Bone Joint J 2013;95-B:770–6.

Risk factors for ligamentum teres tears

PURPOSE

The purpose of this study was to examine the relationship between nontraumatic ligamentum teres (LT) tears and acetabular radiographic architecture.

METHODS

The inclusion criteria for this study were all patients who had anteroposterior pelvis radiographic views and had undergone arthroscopic examination of the LT. The exclusion criteria were Tonnis arthritic grade 3 and traumatic high-energy mechanisms of injury. Radiographic data were measured preoperatively on an anteroposterior pelvis view, including acetabular inclination (AI), lateral center edge (CE) angle, magnitude of cross-over sign, and ischial spine prominence. A Lateral Coverage Index (LCI) was defined as the center edge angle minus acetabular inclination. Hips were divided into 3 groups according to the LCI: (1) high: 34° and above; (2) medium: 19° to 33°; and (3) low: below 19°.

RESULTS

Of the 463 hips (430 patients) included in the study, 226 (49%) had a partial- or full-thickness LT tear. Patients with tears were significantly older than patients without tears (P < .0001), with average ages of 38 and 33 years, respectively. Radiographically, patients with tears had less acetabular retroversion, as reflected by lower ischial spine prominence values and lesser cross-over signs (P = .01 and .0005, respectively). Using the LCI, 115 hips (25%) were classified as high, 236 (50%) as medium, and 114 (25%) as low. Hips with low LCI were 1.74 times more likely to have LT tears than high LCI hips.

CONCLUSIONS

This study found that the presence of LT tears was associated with acetabular bony morphology and age. LT tears were less frequent with high LCI and acetabular retroversion and less frequent in patients younger than 30 years. Further study is needed to establish whether there is a causal relationship between acetabular undercoverage and LT tears and whether LT tears may be a sign of microinstability of the hip.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Arthroscopic ligamentum teres reconstruction

The ligamentum teres (LT) has been studied since the 19th century, and its anatomy and biomechanical function have been well described. Recent advancements in hip arthroscopy have caused increased awareness of LT pathology. Previous reports have estimated the incidence of LT tears during hip arthroscopy to be 4% to 51%, and LT tears have been estimated to be the third most common reason for hip pain in athletes. Biomechanical studies have shown the LT's role in stability of the hip. Despite the growing body of literature on LT anatomy and function, its role as a causative factor in hip pain and hip instability has yet to be clearly defined, and the treatment of LT tears remains controversial. However, in certain cases where hip subluxation and overt instability are related to a traumatic full-thickness tear of the LT, reconstruction of the ligamentum has been suggested. We describe a technique for arthroscopic LT reconstruction using either a semitendinosus autograft or allograft in the supine position.

Hip stability after ligamentum teres resection during surgical dislocation for cam impingement

PURPOSE

The purpose of this study was to investigate whether patients who have undergone surgical hip dislocation with excision of the ligamentum teres exhibited symptoms of a Type I ligamentum teres rupture.

METHOD

A questionnaire was designed to enquire about specific symptoms attributed to Type I injuries (complete rupture) in the literature: gross instability, incomplete reduction, inability to bear weight and mechanical symptoms. 217 consecutive patients were surveyed and 161 patients (75%) returned 168 questionnaires (75%). Mean age was 34 and median follow-up was 51 months (35 to 97).

RESULTS

All patients were able to fully weight bear after surgery while 77% experienced no groin pain and 61% experienced no pain on exercise. 35% of patients experienced popping and locking in their operated hip and 24% had subjective feeling of their hip giving way.

CONCLUSION

Patients who have had surgical excision of the ligamentum teres during open osteochondroplasty for cam deformities do not exhibit symptoms of a Type I ligamentum teres rupture. Our results show that minor instability symptoms may be present but symptoms present more like to Type II (partial) injuries. We propose that Type II injuries be divided into Type IIa; partial tear and Type IIb; iatrogenic rupture.

The layer concept: utilization in determining the pain generators, pathology and how structure determines treatment

The level of understanding of pain in the non-arthritic hip has made significant strides in the last couple of decades beginning with the discoveries of Reinhold Ganz, MD. However, even with the detection of subtle bony abnormalities, including femoroacetabular impingement, a clinician's ability to differentiate pain generators in the hip has been ambiguous. Deciphering the etiology of the pathology versus the pain generator is essential in prescribing the proper treatment. The Layer Concept developed by Dr. Bryan Kelly, is a systematic means of determining which structures about the hip are the source of the pathology, which are the pain generators and how to then best implement treatment. Four layers will be discussed in this article. Layer I, the osseous layer, Layer II, the inert tissue layer, Layer III, the contractile layer and Layer IV, the neuromechanical layer.

Catastrophic failure of hip arthroscopy due to iatrogenic instability: can partial division of the ligamentum teres and iliofemoral ligament cause subluxation?

Hip arthroscopy is an evolving surgical tool, and with any new procedure, it is important to learn from the complications encountered. A patient with mild hip dysplasia and a symptomatic labral tear underwent uneventful hip arthroscopy and labral repair including partial debridement of a hypertrophied ligamentum teres. Despite preservation of the labrum, no pincer resection, and a modest capsulotomy, 3 months, subluxation and joint space narrowing were noted. One year, end-stage arthritis was present, requiring total hip replacement. Instability after hip arthroscopy is due to a number of factors, including excessive rim trimming, capsulotomy, overzealous labral resection, or inadequate labral repair. This report emphasizes the importance of the ligamentum teres and small disruptions of the capsule in patients with mild dysplasia.