[Validity of the Morawietz classification for evaluation of periprosthetic tissue]

PURPOSE OF THE STUDY A consensual classification of the periprosthetic interface membrane obtained at revision total joint arthroplasty was published by Morawietz et al. in 2006. Based on histomorphological criteria, four types of periprosthetic membrane were proposed: type I, aseptic failure; type II, septic failure; type III, combined type (carrying signs of both type I and II); and type IV, indeterminate type. The aim of this study was to find out whether and to what extent the Morawietz system would be suitable for use at an independent institution involved in the evaluation of periprosthetic membranes for a long time. Should it appear that the institution achieved an equally good or even better agreement between the clinical diagnosis and the histopathological finding, this consensus classification could be recommended for routine use. MATERIAL AND METHODS The samples of periprosthetic tissue evaluated in this study were obtained during surgery from the following groups of patients: 66 patients with aseptic loosening of total hip (THA) or knee arthroplasty, 15 patients with infection of THA, 16 patients with THA without any signs of aseptic loosening, osteolysis or infection; 8 patients with hip osteoarthritis and 8 patients with knee osteoarthritis. Sample collection and processing (for purposes of histomorphological evaluation and immunohistochemical staining) was performed according to the established protocol. The tissue samples evaluation was made by an experienced pathologist hand in hand with the method described in the original paper by Morawietz et al. For a more detailed tissue analysis, selected antibodies (CD4, CD8, CD20, IFN-γ and Hsp-60) were visualized by immunohistochemistry. RESULTS The majority of samples from aseptic reoperations were classified as membranes of the type I (79%) and III (16%). Specimens retrieved from septic cases were mostly classified as membranes of type II and III (60% together). The septic membranes showed a significantly higher expression of CD20 protein when compared with both the aseptic (p < 0.0001) and control THA samples (p = 0.003). The membranes retrieved from the surroundings of a stable THA without osteolysis and infection had lower expression levels of Hsp60 and IFN-γ, when compared with those from both aseptic and septic loosening. Finally, Hsp-60 expression was significantly higher in osteoarthritic tissue than in samples from stable THA (p = 0.041). DISCUSSION Morawietz et al. proposed a standardized classification system for evaluation of periprosthetic tissue. As any attempt at generalization of a complex issue, this proposal has certain shortcomings. One of these is poor detection of chronic and low-grade infections. A method that would improve the conventional counting of polymorphonuclear leukocytes is still being sought. In this connection, immunostaining for CD20 combined with an assessment of antimicrobial peptides may be a promising option. The supplementary specimen staining showed that pseudosynovial tissue is much more active in patients carrying infection and the least active in samples from stable THA in which certain tolerance and thus tissue homeostasis might be expected. CONCLUSIONS 1. In this study the distribution of findings classified according to the Morawietz system was similar to the results published in the original study from 2006. 2. The definition of an aseptic membrane (type I) in the Morawietz system meets the requirements of clinical practice (agreement, about 80%). 3. An increased sensitivity for infectious membrane detection can be achieved by using supplementary immunohistochemical staining effective particularly in chronic and low-grade infections. 4. Painless and stable THAs typically have very low expression levels of CD4, CD20 and Hsp-60 proteins, and interferon- -gamma (IFN-γ) as well. Key words: total hip arthroplasty, total knee arthroplasty, aseptic loosening, prosthetic joint infection, tissue analysis, membranes, CD receptors, Hsp-60 protein, IFN-γ.

[Hip pain as a paraneoplastic rheumatic syndrome in a patient with double-hit lymphoma]

A 63-year-old woman consulted the Department of Rheuma-tology for hip pain. X-rays were normal. No signs of arthritis. Four days after she was hospitalized with abdominal pain. CT-urography revealed three enlarged lymph nodes. A biopsy revealed a double-hit lymphoma, an aggressive B-cell lymphoma with translocation of both MYC and BCL2. After starting chemotherapy the hip pain disappeared. A brief complete remission was followed by CNS relapse and death 11 months after diagnosis.

Acute severe hip pain associated with labral calcific deposition disease

Calcific tendinitis is a term used to describe radiographic evidence of calcific deposition within a tendon. This condition, also known as calcium deposition disease, has been described in the gluteus maximus, the peroneus longus tendon, the popliteus tendon, the longus colli muscle in the neck, and the tendon of the rectus femoris. However, most of the literature on calcific tendinitis relates to crystal deposition within the rotator cuff of the shoulder. The peri-articular pain related to calcium deposition may be indolent and chronic, and patients can have varying degrees of functional deficit. Patients also may present with an acute inflammatory event, with severe incapacitation and restricted passive range of motion and a clinical picture that is concerning for septic arthritis. Severe pain associated with calcific tendonitis usually occurs during the resorptive phase, where there is vascular infiltration of the calcium deposits and histologic evidence of phagocytosis. The authors report a case of calcium deposition disease found within the hip labrum with a clinical presentation of acute, atraumatic, debilitating pain in a patient with underlying femoroacetabular impingement. This clinical picture is similar to that described during the resorptive phase seen in calcific tendonitis of the shoulder. The authors attribute this presentation to acute rupture of the calcium deposit into the intra-articular joint space of the hip. To the authors' knowledge, there are no other reports of this clinical presentation in the literature.

Effects of icariin on cytokine-induced ankylosing spondylitis with fibroblastic osteogenesis and its molecular mechanism

The aim of this study is to explore the effects of icariin on cytokine induced ankylosing spondylitis fibroblast osteogenesis type expression and its molecular mechanism. The normal fibroblasts were collected as normal control group, and the fibroblasts of hip joint capsule of AS patients were collected, which were respectively added in fetal bovine serum (group AS), fetal bovine serum and cytokines (BMP-2+TGF-beta 1) (group AS), and cell factor solution (icariin group), and observed of the osteogenic expression of fibroblast, to evaluate the impact of Icariin on it. The ALP activity, the content of collagen, osteocalcin content and cbfa1mRNA and OCmRNA of fibroblast of AS group increased compared to the normal control group and AS control group (P < 0.01), indicating that icariin can significantly inhibit the above changes (P < 0.01). Icariin can inhibit fibroblast further osteogenic differentiation through inhibiting the effect of cytokines on the fibroblast osteogenesis type markers and osteogenic gene expression and osteogenic differentiation.

[Total hip replacement: between normal rehabilitation and complication]

Total hip replacement is a common and succesful treatment of the osteoarthritis of the hip. According to the demographical trends in Switzerland in the coming decades, there will be a significant increase in the demand for total hip replacement surgery. The 20-year survival of a total hip prosthesis is approximately 85%. New prosthesis designs aim to improve the hip biomechanics, sacrifice less bone stock and facilitate "minimal-invasive"' approaches to the hip joint. Severe complications in total hip replacement comprise dislocation, aseptic loosening, infection, periprosthetic fracture and limping. The painful total hip replacement requires thourough and systematic work up of extrinsic and intrinsic causes. A referral to the orthopaedic specialist should be considered early.

Femoroacetabular impingement: a review of current concepts

Femoroacetabular impingement is becoming an increasingly more common diagnosis in the orthopaedic community for hip pain in the younger population. Variations in the femoral head and acetabulum can lead to a sequelae of changes to the cartilage that can lead to osteoarthritis. Diagnosis is made through a combination of patient history, physical examination, and diagnostic imaging. Plain radiographs are a very useful tool for evaluating the bony anatomy, while CT scan and MRI have roles for surgical planning and more definitive diagnosis. Most patients should trial physical therapy prior to consideration for any arthroscopic or open procedures. Long-term outcome studies are being performed to determine if surgical intervention has any impact on quality of life and development of osteoarthritis.

[Greater trochanteric pain syndrome]

Greater trochanteric pain is one of the common complaints in orthopedics. Frequent diagnoses include myofascial pain, trochanteric bursitis, tendinosis and rupture of the gluteus medius and minimus tendon, and external snapping hip. Furthermore, nerve entrapment like the piriformis syndrome must be considered in the differential diagnosis. This article summarizes essential diagnostic and therapeutic steps in greater trochanteric pain syndrome. Careful clinical evaluation, complemented with specific imaging studies and diagnostic infiltrations allows determination of the underlying pathology in most cases. Thereafter, specific nonsurgical treatment is indicated, with success rates of more than 90 %. Resistant cases and tendon ruptures may require surgical intervention, which can provide significant pain relief and functional improvement in most cases.

Mild degenerative changes of hip cartilage in elderly patients: an available sample representative of early osteoarthritis

This study investigated the cellular and molecular changes which occur in cartilage from adults with femoral neck fracture (FNF) and osteoarthritis (OA), and explored the similarities in hip cartilage obtained from elderly patients and patients with early OA. Femoral heads were retrieved from 23 female patients undergoing total hip arthroplasty (THA). This group included 7 healthy patients with FNF (hFNF), 8 elderly adults with FNF (eFNF), and 8 elderly patients with hip OA (OA). After high-field MRI T2 mapping, osteochondral plugs were harvested from the weight-bearing area of femoral heads for subsequent macroscopic, histologic, and immunochemical evaluation. Additionally, the contents of cartilage matrix were analyzed, and gene expression was detected. The surface of cartilage from hFNF and eFNF patients appeared smooth, regular, and elastic, whereas it showed irregularities, thinning, and defects in OA patients. Elevated T2 values and decreased accumulation of glycosaminoglycans (GAGs) were detected in cartilage from eFNF patients. Furthermore, type I collagen accumulation was slightly increased and type X collagen concentration was obviously elevated in eFNF patients; however, type II collagen distribution and the contents and anisotropy of collagen fibrils in eFNF patients showed no significant changes. Consistent with histology and immunohistochemical results, aggrecan was downregulated and type X collagen was upregulated, while collagens types I and II showed no significant changes in eFNF patients. The cellular and molecular characteristics of hip cartilage in eFNF patients who showed no symptoms of OA were similar to those in patients with mild OA. Thus, eFNF cartilage can serve as a comparative specimen for use in studies investigating early OA.

Development of mapped stress-field boundary conditions based on a Hill-type muscle model

Forces generated in the muscles and tendons actuate the movement of the skeleton. Accurate estimation and application of these musculotendon forces in a continuum model is not a trivial matter. Frequently, musculotendon attachments are approximated as point forces; however, accurate estimation of local mechanics requires a more realistic application of musculotendon forces. This paper describes the development of mapped Hill-type muscle models as boundary conditions for a finite volume model of the hip joint, where the calculated muscle fibres map continuously between attachment sites. The applied muscle forces are calculated using active Hill-type models, where input electromyography signals are determined from gait analysis. Realistic muscle attachment sites are determined directly from tomography images. The mapped muscle boundary conditions, implemented in a finite volume structural OpenFOAM (ESI-OpenCFD, Bracknell, UK) solver, are employed to simulate the mid-stance phase of gait using a patient-specific natural hip joint, and a comparison is performed with the standard point load muscle approach. It is concluded that physiological joint loading is not accurately represented by simplistic muscle point loading conditions; however, when contact pressures are of sole interest, simplifying assumptions with regard to muscular forces may be valid.

[Total hip arthroplasty for non-functional bony ankylosed hip in young and middle-aged patients]

OBJECTIVE

To explore the effectiveness of total hip arthroplasty (THA) for non-functional bony ankylosed hip in young and middle-aged patients.

METHODS

Between January 2010 and March 2013, 14 cases (19 hips) of non-functional bony ankylosed hip were treated by THA. There were 9 males and 5 females, aged 37.5 years on average (range, 23- 58 years). The left hip was involved in 6 cases, the right hip in 3 cases, and bilateral hips in 5 cases. The causes were tuberculosis in 2 patients, ankylosing spondylitis in 5 patients, traumatic arthritis in 5 patients, osteoarthritis in 1 patient, and suppurative infection in 1 patient. The disease duration was 7-18 years with an average of 8.9 years. Flexion stiffness was observed in 10 hips, flexion abduction stiffness in 6 hips, and flexion adduction shortening stiffness in 3 hips. Only 5 patients could walk with a crutch before operation. Harris hip score was 24.368 ± 7.625.

RESULTS

The average operation time was 63.4 minutes (range, 50-90 minutes). The average intraoperative blood loss was 196.8 mL (range, 100-400 mL). Patients obtained primary healing of incision; no complication of neurovascular injury, fracture, joint dislocation, or infection occurred. All patients were followed up 2.2 years on average (range, 1 year to 4 years and 3 months). The Harris score was 86.837 ± 7.742 at last follow- up, showing significant difference when compared with preoperative score (t = -41.956, P = 0.000). The results were excellent in 5 hips, good in 11 hips, fair in 2 hips, and poor in 1 hip, with an excellent and good rate of 84.2%. All patients could basically take care of themselves; 2 patients could walk with crutch, and the other patients could walk without crutch. X-ray films showed that prosthesis was in good position; no shifting, loosening, or sinking was found. Heterotopic ossification occurred in 2 hips.

CONCLUSION

THA is an effective surgical approach to treat non-functional bony ankylosed hip in young and middle- aged patients.

Septic arthritis of the hip in a Cambodian child caused by multidrug-resistant Salmonella enterica serovar Typhi with intermediate susceptibility to ciprofloxacin treated with ceftriaxone and azithromycin

Septic arthritis is a rare complication of typhoid fever. A 12-year-old boy without pre-existing disease attended a paediatric hospital in Cambodia with fever and left hip pain. A hip synovial fluid aspirate grew multidrug-resistant Salmonella enterica ser. Typhi with intermediate susceptibility to ciprofloxacin. Arthrotomy, 2 weeks of intravenous ceftriaxone and 4 weeks of oral azithromycin led to resolution of symptoms. The optimum management of septic arthritis in drug-resistant typhoid is undefined.

MR imaging with metal artifact-reducing sequences and gadolinium contrast agent in a case-control study of periprosthetic abnormalities in patients with metal-on-metal hip prostheses

OBJECTIVE

To apply and compare magnetic resonance imaging (MRI) metal artifact reducing sequences (MARS) including subtraction imaging after contrast application in patients with metal-on-metal (MoM) hip prostheses, investigate the prevalence and characteristics of periprosthetic abnormalities, as well as their relation with pain and risk factors.

MATERIALS AND METHODS

Fifty-two MoM prostheses (35 cases with pain and or risk factors, and 17 controls) in 47 patients were examined in a 1.5-T MR scanner using MARS: turbo spin echo (TSE) with high readout bandwidth with and without view angle tilting (VAT), TSE with VAT and slice encoding for metal artifact correction (SEMAC), short tau inversion recovery (STIR) with matched RF pulses, and post-contrast imaging. The relations of MRI findings to pain and risk factors were analyzed and in five revised hips findings from operation, histology, and MRI were compared.

RESULTS

TSE VAT detected the highest number of osteolyses. Soft tissue mass, effusion, and capsular thickening were common, whereas osteolysis in acetabulum and femur were less frequent. Contrast enhancement occurred in bone, synovia, joint capsule, and the periphery of soft tissue mass. There was no significant relation between MRI findings and pain or risk factors.

CONCLUSIONS

MARS and gadolinium subtraction imaging are useful for evaluation of complications to MoM prosthesis. TSE VAT had the highest sensitivity for osteolysis. Contrast enhancement might indicate activation of aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL). Pain, small head, or steep prosthesis inclination angle are not useful predictors of periprosthetic abnormalities, and wide indications for MR follow-up are warranted.

[Post-partum transient osteoporosis of the hip causing pain]

Transient osteoporosis of the hip (TOH) affects pregnant women in the third trimester of pregnancy. Magnetic resonance imaging plays an important role in the diagnosis and shows a pattern of bone marrow oedema. We report a case of TOH post-partum with involvement of both hips in a 34-year-old woman. She was known with undifferentiated spondyloartritis since 2004, which posed a diagnostic challenge. The reported patient was treated conservatively avoiding lactation, weight bearing activities, increased intake of calcium and vitamin D and recovered without further medical treatment.

Magnetic Resonance Imaging Findings in the Symptomatic Hips of Younger Retired National Football League Players

BACKGROUND

American football players have an increased level of risk for hip injuries because of the high level of contact, biomechanical load, and anatomic strain placed on the hip joint. Many injuries are attributed to soft tissue injury rather than intra-articular lesions. However, because of improved imaging and increased knowledge, physicians are attributing unexplained hip pain to intra-articular lesions with increasing frequency.

PURPOSE

To assess the prevalence of pathologic intra-articular hip lesions in a younger, retired National Football League (NFL) player cohort evaluated for persistent hip pain.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A retrospective chart review was performed of magnetic resonance imaging (MRI) on retired NFL players evaluated at an orthopaedic clinic for persistent hip pain. All MRIs were performed at the same location and reviewed by the same independent radiologist. The study included 62 hips; MRI was used to evaluate 27 hips, and MRI arthrogram was used to evaluate 35 hips. Images were assessed for labral tears, chondral lesions, ligamentum teres (LT) tears, bone cysts, osteophytes, loose bodies, trochanteric bursitis, and alpha angle. Player demographics, including position and seasons played, were recorded.

RESULTS

From February 2011 to December 2012, a total of 50 retired players from the NFL (average age, 33 years; range, 27-39 years) received impairment evaluations assessing all symptomatic joints. Thirty-eight (76%) players had hip complaints and underwent a dedicated hip MRI. Twenty-four players (63%) had bilateral hip pain, for a total of 62 hips evaluated. There were 55 (89%) labral tears, 61 (98%) chondral lesions, and 50 (81%) partial or complete LT tears identified on MRI. Additional findings included 3 (5%) hips with osteophytes, 9 (14.5%) with subchondral bone cysts, and 3 (5%) with paralabral cysts. None of the players were found to have trochanteric bursitis or loose bodies. Fifty-eight of 62 alpha angles could be measured, for a mean of 59° (range, 39°-77°). The majority of players were defensive players (63%), while the remainder were offensive players (34%) and 1 special teams player. Position breakdown was as follows: 29% were defensive backs, 16% played the defensive line, 18% were linebackers, 13% were fullbacks, 11% were wide receivers, 5% played the offensive line, and the remaining 8% were kickers, running backs, and quarterbacks.

CONCLUSION

This study demonstrated a high incidence of intra-articular pathologic lesions of the hip in a younger cohort of retired NFL players. The majority of players had bilateral hip pain. The most common finding was chondral lesions, followed by labral tears. Future research is needed to further elucidate incidence and treatment outcomes using prospective studies examining active and retired players with hip-related injuries.

Finite-element analysis of the effect of basic hip movements on the mechanical stimulus within a proximal femur

Osteoporosis is a serious and multifactorial disease. The number of people affected with osteoporosis is increasing due to the lengthening of life expectancy. Currently, unlike the genetic, nutritional and hormonal factors that have been the focus of most studies of osteoporosis, mechanical stimuli that potentially can produce an increase in bone strength have not been well studied. Studies suggest that the relationship between the health of the bone and mechanical stimuli occurs through bone adaptive remodeling, which is activated by means of the shear stress transmitted by the interstitial fluid flow. The present work consists of a finite element analysis of a femur to simulate the basic movements of the hip (flexion, extension, abduction, and adduction) to compare the shear stresses in a common zone of fracture and in the critical mechanical strength zones of the femoral head. A comparison of the distribution and magnitude of the shear stresses was performed to estimate the movement that could induce a more rapid adaptive bone remodeling. This study is the first step in the development of a physical therapy for a preventive rehabilitation that helps to prevent patients with low bone mineral density to avoid suffering osteoporosis hip fractures. The finite element model was constructed using a free-access three-dimensional standardized femur obtained from the Instituti Ortopedici Rizzoli, Bologna, Italy. The mechanical properties and the muscular forces were obtained from a specialized bibliography. We conclude that the movements that exhibit a higher mean value and a good shear stress distribution in the femoral neck are hip extension and abduction.

Early infection of hip joint prosthesis by Clostridium difficile in an HIV-1 infected patient

Anaerobes are less frequently described as causative pathogen of prosthetic joint infection (PJI). We report the first case of early PJI after hip arthroplasty due to Clostridium difficile in a diabetic and HIV-1 infected patient with bacteremia. Our patient was successfully treated through surgical debridement and prosthesis retention combined with targeted antibiotic therapy.

Bone mineral density in patients with destructive arthrosis of the hip joint

Recent reports have shown the existence of subchondral insufficiency fracture in rapidly destructive arthrosis of the hip joint (RDA), and the findings suggest that osteopenia is related to the pathogenesis of the rapid progression of this disease. Therefore, we measured bone mineral density (BMD) in RDA patients. We measured BMD of the lumbar spine, radius, and calcaneus using dual-energy X-ray absorptiometry in 19 patients with RDA and 75 with osteoarthritis of the hip (OA) and compared BMD at different skeletal sites between RDA and OA patients. No significant differences were observed in BMD of the lumbar spine, ultradistal radius, mid-radius, and calcaneous between the RDA and OA groups. Our data suggest that RDA is not accompanied by generalized osteoporosis. Factors other than generalized bone status, for example, BMD around the affected hip joint before destruction, need to be analyzed to elucidate the pathophysiological mechanism of RDA.

Arthroscopic treatment of femoral nerve paresthesia caused by an acetabular paralabral cyst

This report describes a rare case of femoral nerve paresthesia caused by an acetabular paralabral cyst of the hip joint. A 68-year-old woman presented with a 6-month history of right hip pain and paresthesia along the anterior thigh and radiating down to the anterior aspect of the knee. Radiography showed osteoarthritis with a narrowed joint space in the right hip joint. Magnetic resonance imaging showed a cyst with low T1- and high T2-weighted signal intensity arising from a labral tear at the anterior aspect of the acetabulum. The cyst was connected to the joint space and displaced the femoral nerve to the anteromedial side. The lesion was diagnosed as an acetabular paralabral cyst causing femoral neuropathy. Because the main symptom was femoral nerve paresthesia and the patient desired a less invasive procedure, arthroscopic labral repair was performed to stop synovial fluid flow to the paralabral cyst that was causing the femoral nerve paresthesia. After surgery, the cyst and femoral nerve paresthesia disappeared. At the 18-month follow-up, the patient had no recurrence. There have been several reports of neurovascular compression caused by the cyst around the hip joint. To the authors' knowledge, only 3 cases of acetabular paralabral cysts causing sciatica have been reported. The current patient appears to represent a rare case of an acetabular paralabral cyst causing femoral nerve paresthesia. The authors suggest that arthroscopic labral repair for an acetabular paralabral cyst causing neuropathy can be an option for patients who desire a less invasive procedure.

Radiographic, histologic, and arthroscopic findings in amorphous calcifications of the hip labrum

PURPOSE

The purpose of this study was to evaluate the clinical, radiographic, histologic, and intraoperative findings of an amorphous calcification involving the acetabular labrum.

METHODS

From October 2008 to April 2013, all patients who underwent arthroscopic hip surgery for symptomatic intra-articular hip disorders and were found to have the characteristic calcific deposit involving the acetabular labrum were included. These patients were reviewed retrospectively on prospectively collected data. Radiographs were retrospectively evaluated for morphologic features of impingement and characteristics of labral calcification.

RESULTS

Sixteen patients were identified as having amorphous calcification at the time of arthroscopy. There were 15 women and 1 man. Mean age was 37.3 years (range, 30 to 50 years). Symptoms were present for a mean of 9.3 months (range, 3 to 48 months). All patients reported anterior groin pain. Fifteen (94%) patients had positive anterior impingement and 9 (56%) had positive results for lateral impingement. Calcifications measured on average 3.2 mm (range, 1.9 mm to 5.6 mm), and 14 had a clear separation from the rim with increased opacity compared with neighboring trabecular bone. Intraoperatively, the characteristic amorphous calcium deposit was located in the anterosuperior labrum, with the deposit found to be accessible from the capsule-labral recess in all cases. All patients had labral tears and all patients had at least one component of femoroacetabular impingement (FAI).

CONCLUSIONS

Calcification in the anterosuperior acetabular labrum presents with a consistent patient demographic and distinct radiographic and arthroscopic presentation that is different from os acetabuli. As with os acetabuli, one should have a high suspicion for FAI when this lesion is encountered.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

[Falls in patients with stroke]

Falls are the most common medical complication during the post-stroke period. Falls are of great concern in this population in particular because of their severe consequences. Stroke survivors have an increased frequency of hip fracture and psychosocial problems such as fear of falling. The most important risk factors for falls in these patients are balance and gait deficits. Balance deficits in post-stroke patients entail reduced postural stability during standing and disturbed responses to self-induced and external balance perturbations. Gait deficits in post-stroke patients involve reduced propulsion at push-off, disturbed hip and knee flexion in the swing phase and disturbed stability in the stance phase. Beneficial effects can be expected from fall prevention programs targeting these deficits. The few studies that have evaluated the efficacy of task-oriented exercises have shown that these programs are the most promising in preventing falls in post-stroke patients. Technological advances in assistive devices also have potential for fall reduction. Larger randomized controlled trials are needed to provide more conclusive evidence.

Fat pad entrapment at the hip: a new diagnosis

PURPOSE

To establish if a positive impingement sign in femoroacetabular impingement (FAI) may result from entrapment of the fat pad located at the anterior head-neck junction of the upper femur. This fat pad is routinely removed before any cam lesion excision.

METHODS

We report a prospective study of 142 consecutive hip arthroscopies for symptomatic FAI where the aim was to remove the arthroscopically identified area of impingement, not necessarily to create a spherical femoral head. Patients were divided into two groups. Group 1 (n = 92; 34 females, 58 males), where a cam-type bony FAI lesion was identified and excised in addition to the fat pad which overlay it, and Group 2 (n = 50; 29 females, 21 males) where the only identified point of impingement was a prominent fat pad. In this situation the fat pad was excised in isolation and the underlying bone preserved. Patients were assessed preoperatively, at six weeks, six months, one year and two years with a modified Harris hip score (mHHS).

RESULTS

Both groups were comparable preoperatively for mean age, mean alpha angle and mean anterior offset ratio. Both groups improved significantly after surgery at all time points. However, Group 1 (fat pad and bone resection) demonstrated 16.0% improvement in mHHS by two years while for Group 2 (fat pad resection only) the improvement was 18.9% (p = 0.628).

CONCLUSIONS

The fat pad found at the anterior head/neck junction of the hip joint can be a source of pain and we propose fat pad entrapment as a new, previously undescribed diagnosis. Our findings also suggest that a large number of cam lesions are being excised unnecessarily and that further efforts should be made to understand the role of the fat pad as a source of groin discomfort.

LEVEL OF EVIDENCE

Level IV, case series.

[Structural and functional characteristics of bone tissue and blood cytokines in health and disease of the joints]

Change of structural and functional state of bone in patients with primary osteoarthrosis of the hip joint compared to healthy individuals is characterized by decreased bone formation with a relative predominance of resorption. Osteopenic syndrome develops in the background of evident imbalance of a blood cytokine profile with increasing the level of proinflammatory and the variability of the level of anti-inflammatory cytokines.

[Greater trochanteric pain syndrome of the hip]

Lateral pain of the hip with point tenderness at the Greater Trochanter is a common musculoskeletal complaint. It is frequently diagnosed as trochanteric bursitis; however, this term is inaccurate because of evident non-inflammatory pathologies, particularly of the abductor tendons of the hip. It is important to differentiate this extra-articular source from an intra-articular or a lower back source of pain. Imaging is useful in cases of trauma, prolonged pain or uncertain diagnosis. Non-operative treatment that involves modifying activities, physiotherapy, analgesics, steroid injections and shock wave therapy is usually helpful. Nevertheless, despite the above treatments, about one third of the patients suffer from chronic pain and disability. These patients may be candidates for operative intervention. Currently, there are endoscopic surgical techniques for local decompression, bursectomy and suture of torn tendons similar to surgery used in the shoulder.

Genome wide analysis indicates genes for basement membrane and cartilage matrix proteins as candidates for hip dysplasia in Labrador Retrievers

Hip dysplasia, an abnormal laxity of the hip joint, is seen in humans as well as dogs and is one of the most common skeletal disorders in dogs. Canine hip dysplasia is considered multifactorial and polygenic, and a variety of chromosomal regions have been associated with the disorder. We performed a genome-wide association study in Dutch Labrador Retrievers, comparing data of nearly 18,000 single nucleotide polymorphisms (SNPs) in 48 cases and 30 controls using two different statistical methods. An individual SNP analysis based on comparison of allele frequencies with a χ(2) statistic was used, as well as a simultaneous SNP analysis based on Bayesian variable selection. Significant association with canine hip dysplasia was observed on chromosome 8, as well as suggestive association on chromosomes 1, 5, 15, 20, 25 and 32. Next-generation DNA sequencing of the exons of genes of seven regions identified multiple associated alleles on chromosome 1, 5, 8, 20, 25 and 32 (p<0.001). Candidate genes located in the associated regions on chromosomes 1, 8 and 25 included LAMA2, LRR1 and COL6A3, respectively. The associated region on CFA20 contained candidate genes GDF15, COMP and CILP2. In conclusion, our study identified candidate genes that might affect susceptibility to canine hip dysplasia. These genes are involved in hypertrophic differentiation of chondrocytes and extracellular matrix integrity of basement membrane and cartilage. The functions of the genes are in agreement with the notion that disruptions in endochondral bone formation in combination with soft tissue defects are involved in the etiology of hip dysplasia.

Fundamental concepts of developmental dysplasia of the hip

To provide the best possible care to patients with developmental dysplasia of the hip, it is helpful to understand the normal growth and development of the hip joint; the pathoanatomy, epidemiology, and diagnosis of the condition; and the natural history of a missed diagnosis of dislocation, subluxation, and dysplasia.

Estimation of trochanteric soft tissue thickness from dual-energy X-ray absorptiometry

Low body mass index is considered to be an important risk factor for fractures in postmenopausal women, in part reflecting its association with lower bone mineral density (BMD). In contrast, obesity is thought to be protective against fracture because of higher BMD and reduced transmitted force of falls as a result of soft tissue padding. Dual-energy X-ray absorptiometry (DXA) is most widely used for the assessment of osteoporosis. We hypothesized that trochanteric soft tissue thickness, as measured directly on whole-body DXA scans, could be estimated using the regional measures of anteroposterior tissue thickness from hip and spine DXA. We identified 376 adult patients who underwent DXA evaluation of the lumbar spine, hip, and whole body at the same visit. The population was randomly divided into 2 equal-sized subgroups, one used to derive prediction equations for trochanteric soft tissue thickness and the other for independent validation. Compared with the actual measurement from the whole-body scans in the validation cohort, the DXA-based estimate gave an unbiased prediction of trochanteric soft tissue thickness (adjusted R² was 0.60 with a standard error of the estimate of 1.35cm), which was significantly better than estimation obtained without DXA information (p < 0.001). Area under the curve discrimination for trochanteric soft tissue thickness in the lowest and highest tertiles was 0.901 (95% confidence interval: 0.849-0.953) and 0.859 (95% confidence interval: 0.805-0.915), respectively. Model-based prediction of trochanteric soft tissue thickness in the lowest and highest tertiles had sensitivities of 78.5% and 91.9% and specificities of 64.4% and 86.8%, respectively. We conclude that regional DXA scans of the spine and hip can be used to estimate the trochanteric soft tissue thickness.

Effects of the assessment of 4 determinants of structural geometry on QCT- and DXA-derived hip structural analysis measurements in elderly women

Previously we reported that the corresponding 2-dimensional (2D) structural geometry measures derived from quantitative computed tomography (QCT) and dual-energy X-ray absorptiometry (DXA) of femoral neck were different. Now, we test the hypothesis that the following 4 measures: areal bone mineral density, W, and 2 new measures, standard deviation (σ) of a normalized mineral mass projection profile distribution and the displacement between centre of mineral mass and geometric centre of mineral mass (δ) of the projection profile allow transformation from one measurement modality to the other with high precision. QCT and DXA scans and hip structural analysis (HSA) performed on 237 women were randomly allocated into cohorts of 118 (cohort A) and 119 (cohort B). Intercepts and gradients from linear regression of the 4 QCT- and DXA-derived measures were obtained from cohort A and used to convert cohort B QCT-derived structural geometry measurements into their DXA equivalent. Corresponding cohort B QCT- and DXA-derived structural geometrical measurements were compared using Bland-Altman plots and regression analysis. Apart from W, comparisons of the 7 nontransformed QCT- and DXA-derived variables were significantly different using paired t-tests. Cross-calibration with the set of 4 base measures resolved the differences in all original variables. These data provide a mechanism for cross-calibrating HSA outcomes acquired using QCT and DXA and demonstrate that a complex 2D digitized structure can be described by 4 variables.

Developmental dysplasia of the hip: diagnosis and management to 18 months

Developmental dysplasia of the hip represents a spectrum of disease ranging from transient neonatal instability to established dislocation. It is accepted that female sex, breech presentation, and family history are risk factors for the disease. Early diagnosis by clinical examination or ultrasound imaging is emphasized, with splint treatment ideally commencing by 6 weeks of age. Treatment using the Pavlik harness is successful in up to 90% of patients. Ultrasound imaging is the gold standard for monitoring a patient during harness wear. Failed splintage or late presentation usually necessitates surgical intervention depending on the patient's age and the severity of the hip dysplasia and displacement.

[Mid-term results of total hip arthroplasty for treatment of ankylosing spondylitis]

OBJECTIVE

To investigate the clinical and radiographic results of total hip arthroplasty (THA) for the treatment of hip arthrosis in patients with ankylosing spondylitis (AS).

METHODS

A retrospective analysis was made on the clinical data from 131 patients (195 hips) who underwent THA for AS between September 2001 and August 2011 with a follow-up period of more than 2 years. There were 100 males (152 hips) and 31 females (43 hips), aged 17-69 years (mean, 33.7 years). The average interval between AS onset and THA was 13.7 years (range, 1-50 years). The left hips were involved in 30 cases, the right hips in 37 cases, and bilateral hips in 64 cases. Preoperative Harris hip score was 18.0 +/- 13.7; the sum passive range of motion was (36.2 +/- 51.2) degrees; and the hip passive-flexion arc was (23.4 +/- 32.6) degrees. In 175 hips with passive flexion of less than 90 degrees, 134 hips had flexion contracture. Based on preoperative X-ray films and CT scan, 195 hips were divided into the non-ankylosed subgroup (86 hips), fibrous ankylosed subgroup (43 hips), and bony ankylosed subgroup (66 hips); and the recovery of hip function was compared between subgroups after operation.

RESULTS

Intraoperative complications included linear fractures of femoral calcar in 4 hips, fractures of acetabular posterior column in 1 hip, femoral shaft fractures in 2 hips, and iatrogenic sciatic nerve injury in 3 hips; postoperative complications included anterior dislocation in 2 hips. The average follow-up period was 51.3 months (range, 24-143 months). Bone healing was observed at 3-6 months after operation (mean, 3.9 months). At last follow-up, the average Harris hip score increased to 86.4 +/- 14.1, the sum passive range of motion increased to (202.0 +/- 28.0) degrees, and the hip passive-flexion arc increased to (93.2 +/- 15.3) degrees, all showing significant differences when compared with preoperative ones (P < 0.05). Based on a four-class scale for subjective satisfaction, the patients were very satisfied, satisfied, and not satisfied with the results of THA in 100, 80, and 15 hips respectively. X-ray films showed radiolucent line (< 2 mm) in 5 acetabular components (zones I and II); heterotopic ossification was observed in 49 hips after THA. There was no significant difference in the Harris hip score among 3 subgroups after THA at last follow-up (P > 0.05). At last follow-up, the degree of passive flexion in the fibrous ankylosed subgroup and bony ankylosed subgroup was significantly lower than that in the non-ankylosed subgroup (P < 0.05), and the sum passive range of motion in the fibrous ankylosed subgroup was significantly lower than that in the non-ankylosed subgroup (P < 0.05), but no significant difference was found in the other variables among the 3 sub groups (P > 0.05).

CONCLUSION

For severe hip arthrosis in patients with AS, the overall outcomes after THA are ideal with a good midterm prosthetic survivorship, a low complication rate, and a high satisfaction of patients. However the hip function after THA is still less satisfactory. [Key words] Ankylosing spondylitis Total hip arthroplasty Hip function Mid-term result

Surgical treatment of developmental dysplasia of the hip

Ideally, developmental dysplasia of the hip is treated early in childhood by nonsurgical methods. If these methods are ineffective, surgical reduction in a nonambulating child is required. A young child (age 6 to 18 months) who requires surgical reduction can be treated by formal anterior open reduction or by the medial Ludloff approach to the hip. Additional bony procedures are usually not required in these young patients. Delayed diagnosis is still common, requiring surgical reduction for children of walking age. These older children usually require formal open reduction (anterior approach) plus an associated bony osteotomy (acetabular, proximal femoral, or, in some cases, both types of osteotomies) to better stabilize the hip. The addition of a proximal femoral derotational shortening osteotomy for open reduction in older children was first used in children older than 3 years, but now it is commonly used in children as young as 2 years. This osteotomy decreases the forces on the reduced hip and minimizes the chances for redislocation and osteonecrosis. In all surgical procedures for developmental dysplasia of the hip, the surgeon must avoid too great a focus on bony osteotomies because the management of soft-tissue abnormalities is critical in achieving a stable reduction.

Legg-Calvé-Perthes disease: an overview with recent literature

The evolving knowledge on Legg-Calvé-Perthes (LCP) demonstrates the utility of studying a rare disease systematically by piecing together the biology and mechanics of this condition and applying clinical observations to improve patient care. As treatments of less common diseases are hard to randomize and study in meaningful numbers, long-term study groups have been created to provide insight into this entity that remains an enigma in many aspects. These studies permit a more evidence-approached guide to prognosis and treatment. Meanwhile, basic science research contributes to our understanding of pathophysiology of the disruption and repair processes that lead to LCP, with the goal of clinical translation. This review of LCP aims to give an overview of the condition, with specific focus on recent literature.

[Clinical characters of culture-negative prosthetic joint infection]

OBJECTIVE

To explore the clinical characters and histopathologic differences between patients with culture-positive and culture-negative prosthetic joint infection (PJI).

METHODS

Between January 2012 and July 2013, 66 PJI patients in accord with diagnostic criteria were enrolled. According to the results of preoperative aspiration and intraoperative cultures, the patients were divided into culture-negative group (CN group, n = 21) and culture-positive group (CP group, n = 45). There was no significant difference in gender, age, height, weight, and body mass index between 2 groups (P > 0.05). Preoperative C reactive protein (CRP), erythrocyte sedimentation rate (ESR), and prosthesis survival time were compared between 2 groups. Intraoperative frozen sections and paraffin sections were both performed to identify infections, and histological typing was performed according to Morawietz's methods.

RESULTS

The preoperative CRP was (1.29 +/- 1.84) mg/dL in CN group and (5.08 +/- 9.57) mg/dL in CP group, showing significant difference (t = 2.094, P = 0.038). The preoperative ESR was (22.86 +/- 28.42) mm/1 h in CN group and (36.74 +/- 31.26) mm/1 h in CP group, showing significant difference (t = 7.761, P = 0.000). The median survival time of prosthesis was 72 months (range, 8-504 months) in CN group and 25 months (range, 15 days-300 months) in CP group, showing significant difference (U = 2.231, P = 0.026). Morawietz's histological typing results showed that 2 cases were rated as type I, 7 cases as type II, and 12 cases as type III in CN group; 6 cases were rated as type I, 25 cases as type II, 13 cases as type III, and 1 case as type IV in CP group. The positive culture rate was 68.18% (45/66), and pathogenic bacteria was dominated by Staphylococcus, accounting for 68.89%.

CONCLUSION

The patients with culture-negative PJI have slow onset and mild inflammatory response, so comprehensive diagnosis should be made based on pathological detection, laboratory examination, and intraoperative cultures.

Diagnosis and management of developmental dysplasia of the hip from triradiate closure through young adulthood

The current treatment of painful hip dysplasia in the mature skeleton is based on acetabular reorientation. Reorientation procedures attempt to optimize the anatomic position of the hyaline cartilage of the femoral head and acetabulum in regard to mechanical loading. Because the Bernese periacetabular osteotomy is a versatile technique for acetabular reorientation, it is helpful to understand the approach and be familiar with the criteria for an optimal surgical correction. The femoral side bears stigmata of hip dysplasia that may require surgical correction. Improvement of the head-neck offset to avoid femoroacetabular impingement has become routine in many hips treated with periacetabular osteotomy. In addition, intertrochanteric osteotomies can help improve joint congruency and normalize the femoral neck orientation. Other new surgical techniques allow trimming or reducing a severely deformed head, performing a relative neck lengthening, and trimming or distalizing the greater trochanter.  An increasing number of studies have reported good long-term results after acetabular reorientation procedures, with expected joint preservation rates ranging from 80% to 90% at the 10-year follow-up and 60% to 70% at the 20-year follow-up. An ideal candidate is younger than 30 years, with no preoperative signs of osteoarthritis. Predicted joint preservation in these patients is approximately 90% at the 20-year follow-up. Recent evidence indicates that additional correction of an aspheric head may further improve results.

Synovial hemangioma of the hip joint in a pediatric patient

Hemangiomas of the articular synovium are rare and commonly associated with recurrent joint swelling and painful limitation of motion. The knee joint is the most commonly involved site, with most patients diagnosed in the second to third decade of life. Although over 200 cases have been reported in the English-language medical literature, only three have originated within the hip joint, all of which were in adult patients reported in the surgical literature. We describe a histologically proven synovial hemangioma of the hip joint in a pediatric patient that invaded the femur, acetabulum, and adjacent soft tissues, with a detailed discussion of the differential diagnosis based on the radiographic and magnetic resonance imaging (MRI) findings.

Fast growing pseudotumour in a hairdresser after metal-on-metal hip resurfacing: a case report

A 44-year-old female hairdresser who underwent metal-on-metal hip resurfacing (MOMHR) for hip osteoarthritis developed a benign pelvic pseudotumour. Elevated levels of chromium and cobalt ions were detected in the blood. Patch testing after pseudotumor formation, showed positive skin reactions to cobalt and nickel. Marked hypereosinophilia was noted, as well as the presence of eosinophils in the pseudotumor mass. A revision to a ceramic-on-ceramic implant was performed. Radiographs showed no implant loosening or bone resorption. We hypothesized that a steep cup positioning as well as hypersensitivity response to the metal nanoparticles and ion release may have induced pseudotumour development. Currently there is no evidence that negative patch testing reduces the probability to develop an adverse reaction to metal debris therefore we suggest to carefully investigate patient medical history regarding occupation exposure and daily contact with jewellery, beauty and cleaning products before implanting MOMHR. The main challenge is to identify a sensitive patient candidate to MOMHR never suspected to be.

Adverse reaction to metal debris after ReCap-M2A-Magnum large-diameter-head metal-on-metal total hip arthroplasty

BACKGROUND AND PURPOSE

The clinical findings of adverse reaction to metal debris (ARMD) following large-diameter-head metal-on-metal total hip arthroplasty (LDH MoM THA) may include periarticular fluid collections, soft tissue masses, and gluteal muscle necrosis. The ReCap-M2a-Magnum LDH MoM THA was the most commonly used hip device at our institution from 2005 to 2012. We assessed the prevalence of and risk factors for ARMD with this device.

METHODS

74 patients (80 hips) had a ReCap-M2a-Magnum LDH MoM THA during the period August 2005 to December 2006. These patients were studied with hip MRI, serum chromium and cobalt ion measurements, the Oxford hip score questionnaire, and by clinical examination. The prevalence of ARMD was recorded and risk factors for ARMD were assessed using logistic regression models. The mean follow-up time was 6.0 (5.5-6.7) years.

RESULTS

A revision operation due to ARMD was needed by 3 of 74 patients (3 of 80 hips). 8 additional patients (8 hips) had definite ARMD, but revision was not performed. 29 patients (32 hips) were considered to have a probable or possible ARMD. Altogether, 43 of 80 hips had a definite, probable, or possible ARMD and 34 patients (37 hips) were considered not to have ARMD. In 46 of 78 hips, MRI revealed a soft tissue mass or a collection of fluid (of any size). The symptoms clicking in the hip, local hip swelling, and a feeling of subluxation were associated with ARMD.

INTERPRETATION

ARMD is common after ReCap-M2a-Magnum total hip arthroplasty, and we discourage the use of this device. Asymptomatic patients with a small fluid collection on MRI may not need instant revision surgery but must be followed up closely.

Pelvic deformity secondary to tensor fascia lata tightness associated with desmoid tumor

The iliotibial band is a thick, condensed fascia that, when contracted, leads to a hip flexion, abduction, and external rotation contracture in addition to other joint contractures. Iliotibial band tightness occurs secondary to iliotibial band friction syndrome, which commonly occurs at the lateral femoral epicondylar region. However, a proximal cause of iliotibial band/tensor fascia lata friction syndrome leading to a secondary hip contracture is swelling around the hip; this swelling being a desmoid tumor has not been explicitly described in the literature. The authors present a rare case of a hip contracture in a 28-year-old active man who presented with a functionally disabling hip flexion contracture of 20° with further flexion possible up to 130°, a 45° abduction contracture, and a 20° external rotation contracture with further rotation possible up to 40° with a bony hard swelling in the left gluteal region. Ober’s test was positive. Opposite hip and spine examinations were normal. The goals of treatment were to establish the causality between the 2 and to diagnose the etiology of the gluteal mass. Radiographs were normal, with only a pelvic obliquity evident. Magnetic resonance imaging revealed an extra-articular mass abutting the iliac blade. Histopathology confirmed the mass to be a desmoid tumor in the left gluteal region. A wide surgical excision of the mass was performed with negative margins; no postoperative radiotherapy was administered. After rigorous physiotherapy, the hip deformity disappeared at 6 months and there was no evidence of recurrence at 2.5-year follow-up, with the patient able to sit cross-legged and squat.

Two or more impingement and/or instability deformities are often present in patients with hip pain

BACKGROUND

Damage to the hip can occur due to impingement or instability caused by anatomic factors such as femoral and acetabular version, neck-shaft angle, alpha angle, and lateral center-edge angle (CEA). The associations between these anatomic factors and how often they occur in a painful hip are unclear but if unaddressed might explain failed hip preservation surgery.

QUESTIONS/PURPOSES

We determined (1) the influence of sex on the expression of impingement-related or instability-related factors, (2) the associations among these factors, and (3) how often both impingement and/or instability factors occur in the same hip.

METHODS

We retrospectively reviewed a cohort of 170 hips (145 patients) undergoing MR arthrography of the hip for any reason. We excluded 58 hips with high-grade dysplasia, Perthes' sequelae, previous surgery, or incomplete radiographic information, leaving 112 hips (96 patients). We measured femoral version and alpha angles on MR arthrograms. Acetabular anteversion, lateral CEA, and neck-shaft angle were measured on pelvic radiographs.

RESULTS

We observed a correlation between sex and alpha angle. Weak or no correlations were observed between the other five parameters. In 66% of hips, two or more (of five) impingement parameters, and in 51% of hips, two or more (of five) instability parameters were found.

CONCLUSIONS

Patients with hip pain frequently have several anatomic factors potentially contributing to chondrolabral damage. To address pathologic hip loading due to impingement and/or instability, all of the anatomic influences should be known. As we found no associations between anatomic factors, we recommend an individualized assessment of each painful hip.

Aggressive granulomatosis after cementless total hip arthroplasty as a result of inflammatory reaction to metal debris: case report

Massive osteolysis and granulomatous pseudotumor tissue reactions are long-term complications of total hip replacement. It is a condition of localized bone resorption in contact with prosthetic material. It is speculated to be a consequence of metal hypersensitivity or inflammatory reaction to excessive wear. Ten years after total cementless hip replacement (metal on polyethylene surface), a 70-year-old patient presented with hip pain and pseudotumor with massive osteolysis of proximal femur on x-ray. Intraoperatively, extensive metallosis with significantly worn metal head (316L stainless steel) and only slightly worn polyethylene insert was found. Upon extraction, parts of the affected tissue and bone that were in direct contact with the prosthesis were sent for histopathologic analysis. Microscopic examination showed necrotic soft and bone tissue, mainly bone marrow with numerous histiocytes and multinucleated giant cells containing lots of pigmented particles (presumed to be metal particles as a result of implant surface wear). In this case, the primary cause of osteolysis and granulomatosis was inflammatory reaction to metal debris. Aggressive granulomatosis has been first described in cemented prostheses and afterwards also in cementless ones. Conditions such as primary or metastatic neoplastic processes and infection should be excluded. The presence of foreign molecular particles due to wear of the prosthesis by different mediators has been presumed to cause an inflammatory reaction that leads to bone resorption and loosening of the prosthesis.

Isolated GH deficiency due to a GHRH receptor mutation causes hip joint problems and genu valgum, and reduces size but not density of trabecular and mixed bone

CONTEXT

The GH/IGF-I axis is important for bone growth, but its effects on joint function are not completely understood. Adult-onset GH-deficient individuals have often reduced bone mineral density (BMD). However, there are limited data on BMD in adult patients with untreated congenital isolated GH-deficient (IGHD). We have shown that adult IGHD individuals from the Itabaianinha, homozygous for the c.57+1G>A GHRHR mutation, have reduced bone stiffness, but BMD and joint status in this cohort are unknown.

OBJECTIVE

The goal is to study BMD, joint function, and osteoarthritis score in previously untreated IGHD adults harboring the c.57+1G>A GHRHR mutation.

DESIGN

This is a cross-sectional study.

METHODS

Areal BMD by dual-energy X-ray absorptiometry was measured in 25 IGHD and 23 controls (CO). Volumetric BMD (vBMD) was calculated at the lumbar spine and total hip. Joint function was assessed by goniometry of elbow, hips, and knees. X-rays were used to measure the anatomic axis of knee and the severity of osteoarthritis, using a classification for osteophytes (OP) and joint space narrowing (JSN).

RESULTS

Genu valgum was more prevalent in IGHD than CO. The osteoarthritis knees OP score was similar in both groups, and knees JSN score showed a trend to be higher in IGHD. The hips OP score and JSN score were higher in IGHD. Areal BMD was lower in IGHD than CO, but vBMD was similar in the two groups. Range of motion was similar in elbow, knee, and hip in IGHD and CO.

CONCLUSIONS

Untreated congenital IGHD due to a GHRHR mutation causes hip joint problems and genu valgum, without apparent clinical significance, reduces bone size, but does not reduce vBMD of the lumbar spine and hip.

Steroid-associated hip joint collapse in bipedal emus

In this study we established a bipedal animal model of steroid-associated hip joint collapse in emus for testing potential treatment protocols to be developed for prevention of steroid-associated joint collapse in preclinical settings. Five adult male emus were treated with a steroid-associated osteonecrosis (SAON) induction protocol using combination of pulsed lipopolysaccharide (LPS) and methylprednisolone (MPS). Additional three emus were used as normal control. Post-induction, emu gait was observed, magnetic resonance imaging (MRI) was performed, and blood was collected for routine examination, including testing blood coagulation and lipid metabolism. Emus were sacrificed at week 24 post-induction, bilateral femora were collected for micro-computed tomography (micro-CT) and histological analysis. Asymmetric limping gait and abnormal MRI signals were found in steroid-treated emus. SAON was found in all emus with a joint collapse incidence of 70%. The percentage of neutrophils (Neut %) and parameters on lipid metabolism significantly increased after induction. Micro-CT revealed structure deterioration of subchondral trabecular bone. Histomorphometry showed larger fat cell fraction and size, thinning of subchondral plate and cartilage layer, smaller osteoblast perimeter percentage and less blood vessels distributed at collapsed region in SAON group as compared with the normal controls. Scanning electron microscope (SEM) showed poor mineral matrix and more osteo-lacunae outline in the collapsed region in SAON group. The combination of pulsed LPS and MPS developed in the current study was safe and effective to induce SAON and deterioration of subchondral bone in bipedal emus with subsequent femoral head collapse, a typical clinical feature observed in patients under pulsed steroid treatment. In conclusion, bipedal emus could be used as an effective preclinical experimental model to evaluate potential treatment protocols to be developed for prevention of ON-induced hip joint collapse in patients.

Two phenotypes of arthropathy in long-term controlled acromegaly? A comparison between patients with and without joint space narrowing (JSN)

BACKGROUND

Arthropathy is an invalidating complication of acromegaly, also in long-term controlled patients, and is radiographically characterized by osteophytes and preserved joint spaces. However, joint space narrowing (JSN) is observed in the minority of patients. It is unknown whether JSN is the end-stage of acromegalic arthropathy or whether this feature develops independently of acromegaly.

OBJECTIVE

To gain insight into the pathophysiology of acromegalic arthropathy, and, more specifically, in the process of JSN, risk factors for radiographic JSN were studied in a cross-sectional study.

METHODS

We studied hips and knees of 89 well-controlled acromegaly patients (mean age 58.3 yr, 51% female). Joints were divided into two groups based on the presence of JSN, defined as an Osteoarthritis Research Society (OARSI) score ≥ 1. Potential risk factors for JSN were assessed, and its relationship to joint complaints. Individual knees and hips were analyzed in a Generalized Estimating Equations model, adjusted for age, sex, BMI and intra-patient effect.

RESULTS

In controlled acromegaly, JSN was found in, respectively, 10.3% and 15.4% of the hips and knees. Increasing age and female sex were associated with more JSN; acromegaly-specific risk factors for JSN were joint-site specific. In the hip, JSN was related to more active disease: higher pre-treatment GH/IGF-1, longer and more severe GH exposure and immediate postoperative cure was less frequently achieved. In the knee, especially previous knee surgery, not acromegaly-specific characteristics, was associated with JSN. The presence of JSN was associated with more joint complaints.

CONCLUSIONS

JSN is an infrequent finding in patients with acromegalic arthropathy, but it is associated with more symptoms. This study indicates that, at least in the hip, early and ongoing GH/IGF-1 activity play a role in JSN development.

Management of labral tears of the hip in young patients

Our understanding of labral tears in young patients has evolved significantly in recent years. Successful outcome depends on addressing all bony impingement to improve the intra-articular environment, and prevent further damage to the labrum and articular cartilage. Improved clinical outcomes are associated with labral repair; in cases of a deficient labrum, arthroscopic reconstruction techniques have been developed, with promising clinical outcomes. This article reviews the anatomy of the acetabular labrum, and discusses the pathogenesis of labral tears as well as various treatment options, including arthroscopic labral repair and reconstruction.

[Regional migrating osteoporosis - a case report]

Regional migrating osteoporosis (RMO) was observed in young man with episodes of bone pain in bearing joints, which migrated from hip to leg and subsequently to knee on the unilateral side. Dynamic scintigraphy (SPECT) carried out during relapse of pain demonstrated increased accumulation of radioizotope in Lisfrank joint, distal epiphysis of femur and proximal epiphysis of tibia on the unilateral side due to hyperperfusion and high metabolic turnover in these regions of the skeleton. Dia-gnosis of RMO was confirmed by magnetic resonance (MRI), which showed bone marrow edema of corresponding regions. Although RMO is relatively benign disease with spontaneous remissions, infection etiology or the more serious avascular necrosis should be taken into account.

Wear testing and particle characterisation of sequentially crosslinked polyethylene acetabular liners using different femoral head sizes

Larger femoral heads lead to a decreased risk of total hip dislocation and an improved range of motion. However, the larger diameter is associated with increased wear rates. The low wear rates of crosslinked polyethylene opens up the possibility of using larger heads. The aim of this experimental study was to evaluate the wear of conventional non-crosslinked versus sequentially crosslinked polyethylene liners in combination with different ceramic head sizes (28, 36, 44 mm). Wear testing was performed in a hip simulator according to ISO 14242. Wear particles from the polyethylene liners were characterized after wear testing. The wear measurements revealed a significant increase in the wear of crosslinked polyethylene liners with larger heads. By sequential crosslinking, however, the gravimetric wear using larger heads was reduced to a fractional amount of the wear using conventional polyethylene. Significant differences were observed for particle morphology but not for the number of particles when comparing non-crosslinked and crosslinked polyethylene.