A novel arthroscopic classification of labral tear in hip dysplasia.

BACKGROUND: Acetabular labral tears cause of pain in patients with symptomatic hip dysplasia. To date, no structured grading system has been developed to evaluate labral tears in these patients. The present study describes a new system of grading labral tears in patients with acetabular dysplasia. METHODS: The data of 66 patients who underwent hip arthroscopy for symptomatic hip dysplasia from March 2014 to February 2018 were reviewed. Labral tears were classified into four groups, based on the occurrence of chondrolabral junction (CLJ) disruption, capsulolabral recess (CLR) disruption, and labral displacement. Labral tears without instability were classified as grade 1 or 2. Partial delamination or blistering of the labrum with minimal fraying at the CLJ was classified as grade 1, whereas labral tears with CLJ disruption were classified as grade 2. Unstable labral tears with CLR disruption followed by CLJ disruption, but without labral displacement, were classified as grade 3, whereas unstable labral tears with CLR and CLJ disruption, but with labral displacement, were classified as grade 4. The radiological and clinical characteristics of patients in each grade were determined including by simple radiographs and MRI/MR arthrography, as were concomitant findings, including rupture of the ligamentum teres, articular cartilage damage, and presence of a paralabral cyst. The surgical options selected for each grade and clinical outcomes, including modified Harris hip scores (mHHS) and Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) scores, were evaluated. Spearman's correlation analyses were performed to assess whether labral tear grade correlated with baseline characteristics, the incidence of concomitant injuries, and the severity of osteoarthritis (OA). The Wilcoxon test for paired data was performed to compare treatment results with pain scores. RESULTS: The study cohort included six men and 53 women of mean ± SD age 39.9 ± 13.0 years (range, 15-66 years). Of the 66 hips, seven (10.6%), 10 (15.2%), 30 (45.5%), and 19 (28.8%) were classified as grades 1-4, respectively. Symptom duration (P = 0.017), preoperative Tönnis OA grade (P < 0.001), cartilage damage (P < 0.001), and the presence of a paralabral cyst (P = 0.001) correlated significantly with baseline tear grade. In all groups, mHHS and WOMAC scores improved after surgical treatment. CONCLUSIONS: Arthroscopic findings of labral tears in patients with hip dysplasia differed from the conventional classification. The classification system proposed in this study will likely be useful for determining the degree of labral tear in patients with hip dysplasia and for predicting treatment outcomes.

Prediction of intra-articular pathology and arthroscopic outcomes for femoroacetabular impingement and labral tear based on the response to preoperative anaesthetic hip joint injections.

OBJECTIVE: This study investigated whether the preoperative response to intra-articular injections is associated with intra-articular pathological findings and arthroscopy outcomes. METHODS: This study included 49 patients who underwent arthroscopic hip surgery for femoroacetabular impingement and labral tear after receiving preoperative hip joint injections. The response to anaesthetic injections was categorized as poor (0-50%) or good (51-100%). With respect to anatomical indices, we evaluated the lateral centre-edge angle (LCEA), acetabular roof obliquity (ARO), vertical-centre-anterior angle (VCA), and the alpha angle (on a lateral view). We evaluated the association between these indices (including the types of hip labral tears and cartilage damage) and the effectiveness of intra-articular injections. RESULTS: The study included 22 men and 27 women, and the mean age of patients was 36.4 years. No statistically significant association was observed between the response to preoperative anaesthetic hip joint injections and patient demographics (age, sex) and anatomical indices (LCEA, ARO, VCA, and alpha angle) (p > 0.05). All patients showed labral damage; however, labral tear classification or cartilage damage was not significantly associated with the effectiveness of joint injections. At the 1-year post-operative follow-up, patients with a good response to anaesthetic hip joint injections showed a significantly better outcome than patients with a poor response to these injections (p < 0.01). CONCLUSION: The response to preoperative anaesthetic hip joint injections may indicate the presence of intra-articular pathology. Furthermore, this association may have predictive value in determining post-operative outcomes following hip arthroscopy.

Biocompatibility of Bespoke 3D-Printed Titanium Alloy Plates for Treating Acetabular Fractures.

Treatment of acetabular fractures is challenging, not only because of its complicated anatomy but also because of the lack of fitting plates. Personalized titanium alloy plates can be fabricated by selective laser melting (SLM) but the biocompatibility of these three-dimensional printing (3D-printed) plates remains unknown. Plates were manufactured by SLM and their cytocompatibility was assessed by observing the metabolism of L929 fibroblasts incubated with culture medium extracts using a CCK-8 assay and their morphology by light microscopy. Allergenicity was tested using a guinea pig maximization test. In addition, acute systemic toxicity of the 3D-printed plates was determined by injecting extracts from the implants into the tail veins of mice. Finally, the histocompatibility of the plates was investigated by implanting them into the dorsal muscles of rabbits. The in vitro results suggested that cytocompatibility of the 3D-printed plates was similar to that of conventional plates. The in vivo data also demonstrated histocompatibility that was comparable between the two manufacturing techniques. In conclusion, both in vivo and in vitro experiments suggested favorable biocompatibility of 3D-printed titanium alloy plates, indicating that it is a promising option for treatment of acetabular fractures.

Bone ingrowth around porous-coated acetabular implant: a three-dimensional finite element study using mechanoregulatory algorithm.

Fixation of uncemented implant is influenced by peri-prosthetic bone ingrowth, which is dependent on the mechanical environment of the implant-bone structure. The objective of the study is to gain an insight into the tissue differentiation around an acetabular component. A mapping framework has been developed to simulate appropriate mechanical environment in the three-dimensional microscale model, implement the mechanoregulatory tissue differentiation algorithm and subsequently assess spatial distribution of bone ingrowth around an acetabular component, quantitatively. The FE model of implanted pelvis subjected to eight static load cases during a normal walking cycle was first solved. Thereafter, a mapping algorithm has been employed to include the variations in implant-bone relative displacement and host bone material properties from the macroscale FE model of implanted pelvis to the microscale FE model of the beaded implant-bone interface. The evolutionary tissue differentiation was observed in each of the 13 microscale models corresponding to 13 acetabular regions. The total implant-bone relative displacements, averaged over each region of the acetabulum, were found to vary between 10 and 60 µm. Both the linear elastic and biphasic poroelastic models predicted similar mechanoregulatory peri-prosthetic tissue differentiation. Considerable variations in bone ingrowth (13-88%), interdigitation depth (0.2-0.82 mm) and average tissue Young's modulus (970-3430 MPa) were predicted around the acetabular cup. A progressive increase in the average Young's modulus, interdigitation depth and decrease in average radial strains of newly formed tissue layer were also observed. This scheme can be extended to investigate tissue differentiation for different surface texture designs on the implants.

Analysis of wear of polyethylene hip joint cup related to its positioning in patient's body.

Polyethylene parts of endoprosthesis are the weakest parts of each medical implant. They can be worn out within several years. During this period, a patient can enjoy good physical efficiency until the wear of polyethylene part limits his/her mobility. Then the reoperation is necessary and positioning of all parts of endoprosthesis has an effect on future patient's mobility and durability of implant. Elements of endoprosthesis during exploitation are heavily loaded both by normal and tangential forces and moments. In this paper, the dependence of wear of polyethylene cup on its positioning in pelvis is the major problem. Wear of the cup is determined by two measures: the depth and volume of a material rubbed off from the contact surface. The sensitivity of the depth of rubbing off is evaluated relative to two angles of anteversion and abduction, and radii of the cup. Numerical results are obtained by using Abaqus FE system with data related to patient's activity identified on the basis of medical reports.

Numerical analysis of the crack growth path in the cement mantle of the reconstructed acetabulum.

In this study, we use the finite element method to analyze the propagation's path of the crack in the orthopedic cement of the total hip replacement. In fact, a small python statement was incorporated with the Abaqus software to do in loop the following operations: extracting the crack propagation direction from the previous study using the maximal circumferential stresses criterion, drawing the new path, meshing and calculating again (stresses and fracture parameters). The loop is broken when the user's desired crack length is reached (number of propagations) or the value of the mode I stress intensity factor is negative. Results show that the crack propagation's path can be influenced by human body posture. The existing of a cavity in the vicinity of the crack can change its propagation path or can absolutely attract it enough to meet it. Crack can propagate in the outward direction (toward the acetabulum bone) and cannot propagate in the opposite direction, the mode I stress intensity factor increases with the crack length and that of mode II vanishes.

Influence of cementless cup surface on stability and bone fixation 2 years after total hip arthroplasty.

Loss of fixation between bone and implant surface is one of the main treatment problems in total hip arthroplasty. It might lead to implant instability, bone loss and treatment failure resulting in revision surgery. Surface modification is a method for improving bone response to implant and increasing implant osseointegration. However, the currently applied modifications such as hydroxyapatite coatings do not meet expectation and do not provide good clinical result. The object of the study was to evaluate the influence of acetabular cup surface modification on fixation and bone remodelling in total hip arthroplasty. Clinical and radiological outcomes were evaluated in patients two years after cementless total hip replacement. Two groups were compared: patients with acetabular component with uncoated titanium surface and patients with hydroxyapatite-coated acetabular surface. Hips X-rays were analysed for early signs of losing stability of acetabular cups. Two years after surgery the analysis of X-rays did not reveal any statistical differences in stability, migration of acetabular components of endoprosthesis between both groups. No differences were also observed in bone remodelling around implants. Particularly high percentage of cups, i.e. 17.64%, were classified into the group with high risk of early implant loosening, i.e., the group with HA coatings. Hydroxyapatite coatings on titanium cementless acetabular cups implanted by press-fit technique have no influence on their stability, bone-implant fixation and the remodelling of bone surrounding an implant two years after surgery.

First insights into human acetabular labrum cell metabolism.

OBJECTIVE: Hip labrum pathology has only begun to emerge as a significant source of groin pain in the last decade since the development of hip arthroscopy. Few data are available on the anatomy, histology and function of this structure. Moreover, no metabolic data exist at cellular level. The aim of this study was to characterize extracellular matrix (ECM) genes and pro-inflammatory mediators expressed by these cells. METHODS: Isolated human acetabular labrum cells were cultured in alginate beads for 10 days and additionally stimulated with interleukin (IL)-1 for 24 h. Gene expression levels and secretion of different ECM genes, enzymes and cytokines were examined by quantitative polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assay (ELISA) to assess the metabolic characteristics of labrum cells. Articular chondrocytes and meniscus cells served as controls. RESULTS: Labrum cells expressed high levels of COL1A1 and low levels of COL2A1, aggrecan and SOX-9 compared to chondrocytes. However, COL2A1 was more expressed by labrum cells than by meniscus cells. The expression of matrix metalloproteinase (MMP)-1/-2/-9, ADAMTS-4 and IL-6 was significantly higher in labrum cells than in chondrocytes. IL-1 suppressed the ECM gene expression levels of labrum cells, but increased the expression levels and release of MMP-1/-3/-9/-13 and ADAMTS-4 and IL-6 by these cells. Remarkably, MMP-9 was only significantly upregulated in acetabular labrum cells. CONCLUSIONS: The findings in this study demonstrated that the acetabular labrum is populated with unique highly active fibrochondrocyte-like cells. These cells are capable of expressing and releasing pro-inflammatory enzymes and cytokines and react to a pro-inflammatory stimulus. In this way, they contribute obviously to disturbed tissue function in hip labrum pathology.

Correlation of computed tomography with histology in the assessment of periprosthetic defect healing.

Computed tomography (CT) may more accurately assess the healing of grafted osteolytic lesions around acetabular components compared with plain radiographs, although clinical validation is lacking. To determine whether clinical or micro-CT imaging could assess accurately the grafted lesion compared with histology, we therefore quantified bone healing and ingrowth to determine an effective rhBMP-2 dose and ratio to allograft bone when grafted adjacent to a cementless porous-coated component. We grafted surgically created acetabular defects in canines (n = 20) before uncemented total hip arthroplasty. At 6 weeks, embedded acetabula were imaged and the CT slice images matched to histology section images. The percentage of bone in the defect and growth into the porous surface was assessed quantitatively. Low-dose rhBMP-2 with allograft (1:5 ratio) resulted in a higher percentage of defect healing (43.8%) than rhBMP-2 alone (29.2%) and a higher percentage of bone ingrowth (15.7%) than allograft bone alone (1.1%) as measured by histology. Micro-CT measurements were similar to histologic measurements of defect healing, whereas clinical CT overestimated periprosthetic bone by 38%. Neither clinical CT nor micro-CT techniques are adequate for assessing ingrowth or the bone-implant interface with metal artifacts.

Cement mantle retention: filling the hole.

Revision total hip surgery requires a number of techniques that optimizes outcomes while minimizing bone loss. One such technique that has proven useful in revision of the femoral components in revision total hip surgery is leaving an intact cement mantle in place and cementing a new prosthesis within the intact cement mantle. Careful patient selection and preoperative planning are essential for the successful implementation of this technique. The appropriate indications are: (1) if the original stem is broken, but the cement mantle is intact, (2) when removing a well-fixed, cemented stem to improve exposure for an acetabular revision, increase femoral offset, or femoral head diameter, and (3) when removing a debonded femoral component. Although the cement-within-cement revision technique is rarely used, it is an important technique to have in your portfolio. However, it is also important to keep in mind some of the drawbacks of cement-within-revisions and to consider these factors when deciding whether this technique is appropriate for a specific patient.

Augmentation of bone growth onto the acetabular cup surface using bone marrow stromal cells in total hip replacement surgery.

Aseptic loosening of acetabular components in total hip arthroplasty is the major cause of implant failure. Our hypothesis was that spraying autologous bone marrow-derived stromal cells (BMSCs) in fibrin glue onto the surface of hydroxyapatite-coated uncemented acetabular components would increase bone formation and contact in a caprine model. Ten million BMSCs were sprayed onto the acetabular cup at the time of surgery. Animals in the control group received fibrin glue only. Ground reaction force measurements were taken preoperatively and at 6 and 12 weeks postsurgery. After retrieval at 12 weeks new bone formation, bone-implant contact and fibrous tissue thickness adjacent to the cup were quantified. Viability and proliferation assays showed that the majority of the BMSCs survived spraying in fibrin glue at pressures of up to 1.5 atm. New bone growth adjacent to the bone implant interface in the BMSC-treated group (71.42 +/- 8.97%) was 30% greater than in control (54.22 +/- 16.56%) although this difference was not statistically significant. However, significantly increased new bone formation was measured at the periphery of the cup (zone 5) in the BMSC-treated group (71.97 +/- 10.91%) when compared with control (23.85 +/- 15.13%, p = 0.028). Bone-implant contact was significantly greater in the BMSC-treated group (20.03 +/- 4.64%) (control: 13.71 +/- 8.32%, p = 0.027); correspondingly, the average thickness of the fibrous tissue membrane where present was significantly reduced at the periphery of the cups in the BMSC-treated group (327.49 +/- 20.38 mum) when compared with control (887.21 +/- 158.89 mum) (p = 0.02). This study has clinical applications as greater bone contact at the cup surface will improve fixation and may decrease longer-term aseptic loosening by preventing wear debris-induced bone loss at the implant interface.

Treatment of metastatic carcinoma to the hip with CT-guided percutaneous acetabuloplasty: report of four cases.

Percutaneous acetabuloplasty (PA) is a promising treatment for painful metastatic lesions of the acetabulum. Four patients were treated with injection of the bone cement polymethylmethacrylate directly into the lesion. After the procedure, all four patients had improvement or relief of their pain and were able to resume weight-bearing activities. The procedure was well tolerated by each patient without morbidity. PA appears to be a reasonable palliative procedure for painful and fragile hips associated with metastatic bone disease.

[Value of a combined ossification prophylaxis with indomethacin and radiotherapy for acetabular fractures]. / Wertigkeit einer kombinierten Ossifikationsprophylaxe mit Indometacin und Bestrahlung bei Azetabulumfrakturen.

BACKGROUND: Heterotopic ossification is a complication in patients with surgically treated acetabular fractures. The incidence is related to the surgical approach (extended iliofemoral, posterior or a combined approach). The objective of this study was to evaluate the incidence of heterotopic ossification in patients with acetabular fractures who received a combined prophylaxis with both a single dose of radiation and indomethacin compared to those who received only a prophylaxis with radiation or indomethacin. PATIENTS AND METHODS: A total of 24 patients with a combined prophylaxis after surgery were examined retrospectively 24 months after trauma. A systematic literature review was performed and our own results were compared with different methods for prophylaxis of heterotopic ossification from the literature. RESULTS: Only one patient developed a heterotopic ossification. In accordance with the literature, combined prophylaxis showed the least incidence of ossification compared to the other methods. Differences in incidence frequencies were significant between the different prophylaxis methods. CONCLUSION: A combined prophylaxis for heterotopic ossification in surgically treated acetabular fractures seems to be a better alternative than a prophylaxis with radiation or indomethacin alone.

Effect of oral diacerein (DAR) in an experimental hip chondrolysis model.

We aimed to reproduce the articular cartilage structural changes in a joint exposed to a metallic implant as in the adolescent pinned hip with persistent joint penetration and secondly, to test the effect of an interleukin inhibitor, diacerein (DAR) in the ensuing articular cartilage lesion. Twenty immature beagles were submitted to a surgical K-wire implantation in the hip with the material left in the joint space for 6 months. Twelve animals were sacrificed for histological and biochemical tests. Eight animals were sacrificed at 10 months (half of them treated with DAR) and analyzed by scanning electron microscopy (SEM) and biochemistry of the articular cartilage. Preoperative and monthly C3 and C4 complement and immunoglobulins serum levels were determined. The histological and the electrophoretic profile changes were significative at 6 months. At 10 months the migration profile (CaCl2) recovered to normal levels in the operated hip and the SEM scores for the acetabulum were similar to the non operated control hip after treatment. The serum level of IgA was elevated at the 4th and 6th month postoperatively. The persistence of a metallic implant resulted in degenerative changes parallel to that described for hip chondrolysis as a complication of in-situ pinning; and the cartilage lesion improved with DAR treatment.

Induction of bone ingrowth from acetabular defects to a porous surface with OP-1.

Reliable ingrowth of bone into porous-coated cementless total hip components can be expected in primary surgery. In the revision scenario, however, bone deficiency frequently is encountered and the remaining bone may have less ingrowth potential. Allograft bone and bone graft substitutes may be successful in healing bone defects, but have virtually no capacity to induce bone growth from the defect into the porous surface. To evaluate the role osteoinductive bone proteins may play in enhancing bone ingrowth, six canines had bilateral total hip arthroplasties with a cementless press-fit porous-coated acetabular component. A defect 8 mm in diameter and 5 mm in depth was created in the superior weightbearing area of each acetabulum. One defect in each animal was filled with recombinant human osteogenic protein-1. Each contralateral defect was filled with allograft bone, left empty (defect healing control), or no defect was created (intact) to serve as a control for ideal conditions for bone ingrowth. The osteogenic protein-treated defects healed more completely than allograft bone-treated or empty defects and achieved a bone density equivalent to the intact acetabulum. Bone ingrowth also occurred to a significantly higher degree in the osteogenic protein group compared with the allograft or empty defects achieving a degree of ingrowth equivalent to the intact acetabulum controls. The osteogenic bone protein was successful in achieving complete defect healing and inducing extensive ingrowth from the defect into the adjacent porous coating.

Rapid chondrolysis after an intra-articular leak of bone cement in treatment of a benign acetabular subchondral cyst: an unusual complication of percutaneous injection of acrylic cement.

Percutaneous injection of methylmethacrylate is now increasingly employed to treat bone lesions, both malignant and benign. However, the risks of this procedure are still to be fully established. In this report, we describe a case of rapid chondrolysis appearing after the intra-articular leakage of cement during injection of an acetabular subchondral cyst, resulting in hip replacement. Although the mechanism of such chondrolysis is unknown, this event suggests a chondrolytic effect of the acrylic cement. Thus, it is essential to systematically search for the presence of an intra-articular passage before injecting bone cement into a peri-articular cyst. This unusual complication highlights the need for rigorous evaluation of the benefits and risks of percutaneous injection of acrylic cement in the treatment of benign lesions, especially close to an articulation.

Radiographic, biomechanical, and pathologic effects of hemoglobin glutamer-200 in dogs undergoing cemented total hip arthroplasty.

OBJECTIVE: To determine whether use of hemoglobin glutamer-200 (bovine) as a partial blood volume replacement in dogs undergoing cemented total hip replacement caused any deleterious effects on the bone-cement or cement-prosthesis interface, exerted any deleterious effects on body organs, or caused any complications during the anesthetic, immediate recovery, or long-term recovery period. ANIMALS: 9 adult dogs. METHODS: Dogs were anesthetized, and 15% of the blood volume was removed. Simultaneously, lactated Ringer's solution was infused, and 6 dogs were given hemoglobin glutamer (1 g/kg of body weight, IV). Unilateral total hip replacement was performed. Limb use was assessed visually, and force-plate and radiographic evaluations were performed before, and 8 weeks after, surgery. Eight weeks after surgery, dogs were euthanatized, necropsies were performed, and prosthetic component pullout forces were determined. RESULTS: There were no significant differences between treated and control dogs in regard to biomechanical (visual assessment of gait, force-plate analysis, femoral and acetabular component pullout forces) and pathologic evaluations (physical examination, CBC, serum biochemical analyses, necropsy, and histologic evaluations). Radiographic signs of loosening of the femoral component were seen in 4 dogs treated with hemoglobin glutamer. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of hemoglobin glutamer as a blood substitute did not appear to have any deleterious effects in dogs undergoing total hip arthroplasty. The radiographic findings, which were discordant with the biomechanical results, merit further investigation.

Diagnostic infiltration of the hip joint with bupivacain in adult acetabular dysplasia.

The authors performed a double-blind randomized study considering the use of selective infiltration of the hip joint with bupivacain 0.5% as a diagnostic tool in mild and moderate acetabular dysplasia in the adult. In 40 patients with symptomatic acetabular dysplasia the hip joint was infiltrated with either bupivacain 0.5% or placebo in a double-blind setting. Patients were scored for pain before the injection and for pain relief on a visual analogue scale (VAS) immediately after the injection and after two weeks. There was no statistically significant difference between the two groups for pain relief and duration of pain relief. Duration of pain relief was significantly related to severity of pain before the injection. Diagnostic infiltration of the hip joint with bupivacain in mild and moderate acetabular dysplasia does not prove to be a reliable diagnostic aid in the decision to treat this condition operatively. However, it might be valuable in cases with advanced osteoarthritis: further studies should be undertaken.

Extensive extraspinal hyperostoses after long-term oral retinoid treatment in a patient with pityriasis rubra pilaris.

We describe a patient with severe pityriasis rubra pilaris in whom extensive extraspinal hyperostoses developed after 13 years of oral retinoid treatment. The most prominent abnormality was a bridging exostosis between the left acetabulum and collum. X-ray examinations of the spine during retinoid therapy showed no abnormalities. During oral retinoid treatment, it is important to ask the patient on a regular basis about any skeletal pains or mobility restriction. Normal spinal x-ray results are no guarantee that a patient is free of hyperostoses. Discontinuation of acitretin therapy resulted in a severe exacerbation of the patient's pityriasis rubra pilaris after 2 weeks. The clinical response to administration of azathioprine was clearly inferior to that of acitretin. However, low-dose oral methotrexate therapy appeared to be a good alternative in this patient, with a clinical result comparable to acitretin and no side effects after 6 months of therapy.