Biochemical markers of bone turnover and development of heterotopic ossification after total hip arthroplasty

A Short Course of Celecoxib Prevents Heterotopic Ossification Following Cementless Total Hip Arthroplasty

Heterotopic ossification (HO) is a common complication after total hip arthroplasty (THA) and can result in pain and loss of motion of the hip. This is the first study in the literature to determine if a short course of Celecoxib is effective in the prevention of HO in patients undergoing cementless THA. In this retrospective study of prospectively collected data, consecutive patients undergoing a primary cementless THA were reviewed at a 2-year follow-up. The Control group consisted of 104 hips that did not receive Celecoxib (Control group), while the 208 hips in the Celecoxib group received 100 mg twice daily for 10 days. Radiographs, patient-recorded outcome measures and range of motion (ROM) were evaluated. Overall, there was a significantly decreased incidence of HO in the Celecoxib group (18.7%) than in the Control group (31.7%) (p = 0.01). The odds that a patient developed HO using Celecoxib were 0.4965 times the odds that a patient developed HO without treatment. Clinically, the Celecoxib group demonstrated significantly greater improvement in their mean WOMAC stiffness (0.35 vs. 0.17, p = 0.02) and physical function scores (3.26 vs. 1.83, p = 0.03) compared to those in the Control group, but there was no difference in the ROM between the two groups. This study is the first to demonstrate that the lowest dose of Celecoxib for a short course of only 10 days is a simple and effective prophylactic treatment option that can significantly reduce the incidence of HO following cementless THA.

The use of alkaline phosphatase as a bone turnover marker after spinal cord injury: A scoping review of human and animal studies

BACKGROUND

Serum alkaline phosphatase (ALP) is measured as an indicator of bone or liver disease. Bone-specific alkaline phosphatase (B-ALP) is an isoform of ALP found in the bone tissue which can predict fractures and heterotopic ossification.

OBJECTIVE

The aim of this scoping review was to explore the current use of ALP and B-ALP in studies using humans or animal models of SCI, and to identify ways to advance future research using ALP and B-ALP as a bone marker after SCI.

RESULTS

HUMAN STUDIES: 42 studies were included. The evidence regarding changes or differences in ALP levels in individuals with SCI compared to controls is conflicting. For example, a negative correlation between B-ALP and total femur BMD was observed in only one of three studies examining the association. B-ALP seemed to increase after administration of teriparatide, and to decrease after treatment with denosumab. The effects of exercise on ALP and B-ALP levels are heterogeneous and depend on the type of exercise performed. ANIMAL STUDIES: 11 studies were included. There is uncertainty regarding the response of ALP or B-ALP levels after SCI; levels increased after some interventions, including vibration protocols, curcumin supplementation, cycles in electromagnetic field or hyperbaric chamber. Calcitonin or bisphosphonate administration did not affect ALP levels.

CONCLUSION

Researchers are encouraged to measure the bone-specific isoform of ALP rather than total ALP in future studies in humans of animal models of SCI.

Exosomes for gene therapy effectively inhibit the endothelial-mesenchymal transition in mouse aortic endothelial cells

Background

Heterotopic ossification (HO) can limit joint activity, causes ankylosis and impairs the function and rehabilitation of patients. Endothelial to mesenchymal transition (EndMT) plays an important role in the pathogenesis of HO, and high expression of SMAD7(Mothers Against Decapentaplegic Homolog 7) in endothelial cells can effectively reverse the TGF-β1 mediated EndMT. This article studied an appropriately engineered exosome with high biocompatibility and good targeting property to administrate SMAD7 gene therapy to inhibit the EndMT.

Methods

Exosomes from mouse aortic endothelial cells were cultured and harvested. DSPE-PEG and antibody CD34 were combined to exosomes to synthesize the endothelial cell targeting exosome vector (Exosome-DSPE-PEG-AbCD34). The biocompatibility, stability, targeting and cell internalization of exosome vector were tested, then the Exosome-DSPE-PEG-AbCD34 was loaded with Smad7 plasmid and administrated to MAECs to examine its therapeutic effect on EndMT of MAEC mediated by TGF-β1.

Results

The Exosome-DSPE-PEG-AbCD34 has no impact on MAEC cell viability at high concentration, and exosome-DSPE-PEG-Ab_CD34 could be stably stored at 4°C and 37°C for at least 8 days. Exosome-DSPE-PEG-Ab_CD34 has better targeting property to MAEC cells and can enter into the cells more effectively. The Exosome-DSPE-PEG-Ab_CD34-Smad7 could significantly increase the level of SMAD7, decrease the expression of TGF-β1, and effectively reverse the EndMT of MAEC mediated by TGF- β1 in MAEC cells.

Conclusions

The synthesized Exosome-DSPE-PEG-AbCD34-Smad7 has good biological properties and can effectively reverse the EndMT of MAEC mediated by TGF-β1. Thus, Exosome-DSPE-PEG-AbCD34-Smad7 may has the potential for the prevention and treatment of HO.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04896-0.

Prognostic Value of Bone Formation and Resorption Proteins in Heterotopic Ossification in Critically-Ill Patients. a Single-Centre Study

Introduction

A potential complication in critically ill patients is the formation of bone in soft tissues, termed heterotopic ossification. The exact pathogenetic mechanisms are still undetermined. Bone morphogenetic proteins induce bone formation, while signalling through the receptor activator of nuclear factor kappa-Β (RANK) and its ligand (RANKL), regulates osteoclast formation, activation, and survival in normal bone modelling and remodelling. Osteoprotegerin protects bone from excessive bone loss by blocking RANKL from binding to RANK.

Aim

The study aimed to investigate these molecules as potential prognostic biomarkers of heterotopic ossification development in critically ill patients.

Materials and Methods

In this prospective observational study, BMP-2, RANKL, and osteoprotegerin were measured by ELISA in twenty-eight critically-ill, initially non-septic patients, on admission to an ICU, seven days post-admission, and thirty days after ICU discharge.

Results

In the critically-ill cohort, nine of the twenty-eight patients developed heterotopic ossification up to the 30-day follow-up time-point. The patients who developed heterotopic ossification exhibited significantly reduced BMP-2 and RANKL levels on ICU admission, compared to patients who did not; Osteoprotegerin readings were similar in both groups.

Conclusions

Critically-ill patients who will subsequently develop heterotopic ossification, have significantly lower BMP-2 and RANKL levels at the time of ICU admission, suggesting that these proteins may be useful as prognostic markers for this debilitating condition.

A review of the biomarkers and in vivo models for the diagnosis and treatment of heterotopic ossification following blast and trauma-induced injuries

Heterotopic ossification (HO) is the process of de novo bone formation in non-osseous tissues. HO can occur following trauma and burns and over 60% of military personnel with blast-associated amputations develop HO. This rate is far higher than in other trauma-induced HO development. This suggests that the blast effect itself is a major contributing factor, but the pathway triggering HO following blast injury specifically is not yet fully identified. Also, because of the difficulty of studying the disease using clinical data, the only sources remain the relevant in vivo models. The aim of this paper is first to review the key biomarkers and signalling pathways identified in trauma and blast induced HO in order to summarize the molecular mechanisms underlying HO development, and second to review the blast injury in vivo models developed. The literature derived from trauma-induced HO suggests that inflammatory cytokines play a key role directing different progenitor cells to transform into an osteogenic class contributing to the development of the disease. This highlights the importance of identifying the downstream biomarkers under specific signalling pathways which might trigger similar stimuli in blast to those of trauma induced formation of ectopic bone in the tissues surrounding the site of the injury. The lack of information in the literature regarding the exact biomarkers leading to blast associated HO is hampering the design of specific therapeutics. The majority of existing blast injury in vivo models do not fully replicate the combat scenario in terms of blast, fracture and amputation; these three usually happen in one insult. Hence, this paper highlights the need to replicate the full effect of the blast in preclinical models to better understand the mechanism of blast induced HO development and to enable the design of a specific therapeutic to supress the formation of ectopic bone.

Severe heterotopic ossification in a seronegative spondyloarthritis patient after cervical Bryan disc arthroplasty: A case report

BACKGROUND

Cervical disc arthroplasty (CDA) is an alternative treatment to traditional interbody fusion that maintains postoperative cervical spine mobility. However, the CDA postoperative period is impacted by osteolysis, subsidence, metallosis, or heterotopic ossification (HO). We report a case of severe HO in a seronegative spondyloarthritis patient after cervical Bryan disc arthroplasty.

CASE SUMMARY

A 34-year-old man received hybrid surgery for C4-C5 and C5-C6 arthroplasty with Bryan discs and C6-C7 arthrodesis with polyetheretherketone cage due to traumatic herniation of the intervertebral disc (HIVD). After four years, cervical spine radiographs revealed severe HO around the Bryan discs over the C4-C5 and C5-C6 levels. The magnetic resonance image revealed HIVD over the C3-C4 level with spinal cord compression. Seronegative spondyloarthritis was diagnosed after consultation with a rheumatologist. A second CDA for the adjacent segment disease HIVD with Baguera C disc over the C3-C4 level achieved an excellent outcome.

CONCLUSION

Minimizing intraoperative tissue trauma and achieving postoperative interbody stability avoid soft tissue traction to prevent HO formation after CDA.

Weight-Bearing Physical Activity Influences the Effect of Vitamin D on Bone Turnover Markers in Patients with Intellectual Disability

OBJECTIVES

Individuals with intellectual disabilities (IDs) are at increased risk for low bone mass and fragility fractures, and those who are nonambulatory may be at even higher risk. Patients with IDs often are vitamin D deficient, but there is little information concerning how vitamin D treatment of patients with IDs affects markers of bone formation and resorption.

METHODS

We performed a retrospective analysis of 23 institutionalized individuals with IDs who were the subject of a performance improvement continuing medical education project designed to reduce risk for fracture by optimizing serum vitamin D levels. Patients were divided into those with normal weight-bearing (NWB) physical activity (15 patients: 14 men, 1 woman) and those with low weight-bearing (LWB) physical activity (8 patients: 7 men, 1 woman). All of the subjects received 50,000 IU of vitamin D₃ weekly for 4 to 8 weeks, followed by a maintenance dose of 50,000 IU monthly for 3 to 6 months. Bone turnover markers (type 1 cross-linked C-telopeptide [CTX], type 1 N-terminal propeptide [P1NP], and parathyroid hormone [PTH]) and 25(OH)-vitamin D levels were measured before and after vitamin D supplementation.

RESULTS

At baseline, there were no significant differences in the serum levels of 25OH-D, PTH, P1NP, or CTX between the two groups (NWB and LWB). Vitamin D levels were increased to a higher value in LWB subjects than in NWB subjects (61 ± 4.1 vs 48.4 ± 2.2 ng/mL, P < 0.001). Vitamin D treatment suppressed PTH (20.5% ± 14.3% vs 31.4% ± 7.7%, P = not significant) and P1NP (33.0% ± 6.2% vs 29.4% ± 6.9%, P = not significant) similarly in both groups. Although CTX levels declined by 26.4% ± 5.3% (P = 0.0002) in NWB individuals (as anticipated), vitamin D supplementation resulted in an unexpected 25.8% ± 8% increase (P = 0.01) in CTX in LWB individuals, suggesting osteoclast activation.

CONCLUSIONS

Although high-dose vitamin D appeared to suppress osteoclast activity in NWB adults with IDs, the increase in serum CTX levels in those with LWB activity implies activation of osteoclasts that could exacerbate their unique low bone mass and increase fracture risk. The results support the use of a lower-dose vitamin D regimen in this patient group with LWB.

Heterotopic Ossification: A Challenging Complication of Total Hip Arthroplasty: Risk Factors, Diagnosis, Prophylaxis, and Treatment

Background

This review is intended to summarize the risk factors, classification, diagnosis, and treatment of heterotopic ossification (HO) of previously published studies.

Results

Heterotopic ossification is a common complication of total hip arthroplasty. Its prevalence is not the same in all of the patient groups. Frequency of HO varies from 15 to 90%. Hip ankylosis, male gender, and previous history of HO are said to be risk factors with a significant level. Diagnosis is based on a single AP radiograph: the Brooker classification that divides HO into four grades is the most commonly used. The confirmation test that can be used is a bone scan. A great amount of bone metabolic turnover markers have been tested, but none of them seems to be relevant in case of prevention or diagnosis of HO. The most effective prophylactic treatment is radiotherapy or administration of nonsteroidal anti-inflammatory drugs. Over the years a lot of different RT protocols have been tested. Nowadays the most often used regimen is 7 Gy given postoperatively in a single dose. The most commonly prescribed drug in prophylaxis of HO is indomethacin. Also, the efficacy of ibuprofen and diclofenac was proven. Recently researchers focused on selective COX-2 inhibitors. They appear to be as effective as nonselective NSAIDs having less side effects. The one and only treatment of HO is a revision arthroplasty.

Heterotopic Ossification in Primary Total Hip Arthroplasty: which is the role of drainage?

Background and aim of the work: The Heterotopic Ossification (HO) is a common complication following Total Hip Arthroplasty (THA). Although there is no concordance in Literature regarding the etiopathogenic mechanism, various HO risk factors have been recognized, both related to the patient and associated with the surgical procedureLiterature does not consider the use of intra-articular drainage as a possible risk factor. Our hypothesis is that this item can contribute to the development of HO. Materials and Methods: 425 implants of hip arthroplasty performed between 2014 and 2017 at the Ortopedic Clinic of Udine were included in the study. No patient performed pre-operative or post-operative anti-HO prophylaxis during follow-up. Radiographs of preoperative and postoperative at 1 year were analyzed according to the Brooker Classification.Results: The incidence of HO in patients with intra-articular drainage is 24.6%, while the incidence of HO in patients without intra-articular drainage is 15.3%, with a statistically significant difference. Conclusions: The data obtained suggest to consider the use of intra-articular drainage as a possible intra-operative risk factor for HO. This is a retrospective cohort study, so we need more studies and more robust experimental designs to confirm these results. (www.actabiomedica.it)

A survey of proteomic biomarkers for heterotopic ossification in blood serum

Background

Heterotopic ossification (HO) is a significant problem for wounded warriors surviving high-energy blast injuries; however, currently, there is no biomarker panel capable of globally characterizing, diagnosing, and monitoring HO progression. The aim of this study was to identify biomarkers for HO using proteomic techniques and blood serum.

Methods

Isobaric tags for relative and absolute quantitation (iTRAQ) was used to generate a semi-quantitative global proteomics survey of serum from patients with and without heterotopic ossification. Leveraging the iTRAQ data, a targeted selection reaction monitoring mass spectrometry (SRM-MS) assay was developed for 10 protein candidates: alkaline phosphatase, osteocalcin, alpha-2 type I collagen, collagen alpha-1(V) chain isoform 2 preprotein, bone sialoprotein 2, phosphatidate phosphatase LPIN2, osteomodulin, protein phosphatase 1J, and RRP12-like protein.

Results

The proteomic survey of serum from both healthy and disease patients includes 1220 proteins and was enriched for proteins involved in the response to elevated platelet Ca⁺², wound healing, and extracellular matrix organization. Proteolytic peptides from three of the ten SRM-MS proteins, osteocalcin preprotein, osteomodulin precursor, and collagen alpha-1(v) chain isoform 2 preprotein from serum, are potential clinical biomarkers for HO.

Conclusions

This study is the first reported SRM-MS analysis of serum from individuals with and without heterotopic ossification, and differences in the serum proteomic profile between healthy and diseased subjects were identified. Furthermore, our results indicate that normal wound healing signals can impact the ability to identify biomarkers, and a multi-protein panel assay, including osteocalcin preproprotein, osteomodulin precursor, and collagen alpha-1(v) chain isoform 2 preprotein, may provide a solution for HO detection and monitoring.

Electronic supplementary material

The online version of this article (doi:10.1186/s13018-017-0567-2) contains supplementary material, which is available to authorized users.

Heterotopic Ossification in Primary Total Hip Arthroplasty Using the Direct Anterior vs Direct Lateral Approach

BACKGROUND

The formation and severity of heterotopic ossification (HO) may be influenced by type of surgical approach. Our hypothesis was that because of differences in soft tissue dissection, differences exist in HO formation in primary total hip arthroplasty using direct anterior (DA) vs direct lateral (DL) approach.

METHODS

A total of 1482 consecutive patients with DL (736) or DA (746) approach and similar perioperative care protocol during 2009-2011 were retrospectively studied. No patient received prophylactic radiotherapy. Preoperative and 6-month postoperative radiographs were reviewed based on Brooker classification.

RESULTS

The incidence of overall HO was higher in DL (36.1%) vs DA group (19.4%, P < .001) but high-grade HO (Brooker ≥3) was not significantly different among the groups (3.9% for DL and 3.0% for DA groups). No patient required further surgery for HO resection.

CONCLUSION

The type of approach (DA vs DL) did not seem to have a major influence on the short-term incidence of high-grade HO based on this radiographic analysis.

Ethnic differences in heterotopic ossification following total hip arthroplasty

Aims

We aimed to assess the influence of ethnicity on the incidence of heterotopic ossification (HO) after total hip arthroplasty (THA).

Patients and Methods

We studied the six-month post-operative anteroposterior radiographs of 1449 consecutive primary THAs (1324 patients) and retrospectively graded them for the presence of HO, using the Brooker Classification.

Results

Based on multivariate analysis, African-American ethnicity was an independent risk factor for HO formation following THA with an adjusted odds ratio (OR) of 2.6 (95% confidence interval (CI) 1.3 to 5.2, p = 0.007) for severe HO and 1.9 (95% CI 1.3 to 2.7, p < 0.001) for any grade of HO.

Conclusion

Given the increased risk of HO formation, particularly high grade HO, and the potentially poorer outcomes associated with HO, it is important to consider using prophylaxis against HO in patients of African-American ethnicity undergoing THA. Take home message: African Americans are at an increased risk for developing heterotopic ossification and thus may benefit from HO prophylaxis. Cite this article: Bone Joint J 2016;98-B:761–6.

Spontaneous Knee Ankylosis through Heterotopic Ossification after Total Knee Arthroplasty

This paper reports on a case of total ankylosis of the knee after a cruciate-sacrificing cemented total knee arthroplasty (TKA). An 82-year-old female patient previously underwent primary TKA for osteoarthritis twenty years ago in our institution. She had recovered uneventfully and returned to her regular activities. There was no history of postsurgical trauma; however, she progressively lost knee range of motion. Radiographs revealed severe bridging heterotopic ossification.

Early detection of heterotopic ossification using near-infrared optical imaging reveals dynamic turnover and progression of mineralization following Achilles tenotomy and burn injury

Heterotopic ossification (HO) is the abnormal formation of bone in soft tissue. Current diagnostics have low sensitivity or specificity to incremental progression of mineralization, especially at early time points. Without accurate and reliable early diagnosis and intervention, HO progression often results in incapacitating conditions of limited range of motion, nerve entrapment, and pain. We hypothesized that non-invasive near-infrared (NIR) optical imaging can detect HO at early time points and monitor heterotopic bone turnover longitudinally. C57BL6 mice received an Achilles tenotomy on their left hind limb in combination with a dorsal burn or sham procedure. A calcium-chelating tetracycline derivative (IRDye 680RD BoneTag) was injected bi-weekly and imaged via NIR to measure accumulative fluorescence for 11 wk and compared to in vivo microCT images. Percent retention of fluorescence was calculated longitudinally to assess temporal bone resorption. NIR detected HO as early as five days and revealed a temporal response in HO formation and turnover. MicroCT could not detect HO until 5 wk. Confocal microscopy confirmed fluorophore localization to areas of HO. These findings demonstrate the ability of a near-infrared optical imaging strategy to accurately and reliably detect and monitor HO in a murine model.

Indomethacin prophylaxis for heterotopic ossification after acetabular fracture surgery increases the risk for nonunion of the posterior wall

OBJECTIVES

To determine if indomethacin has a positive clinical effect for the prophylaxis of heterotopic ossification (HO) after acetabular fracture surgery. To determine whether indomethacin affects the union rate of acetabular fractures.

DESIGN

Prospective randomized double-blinded trial.

SETTING

Level 1 regional trauma center.

PATIENTS

Skeletally mature patients treated operatively for an acute acetabular fracture through a Kocher-Langenbeck approach.

INTERVENTION

Patients were randomly allocated to 1 of 4 groups comparing placebo (group 1) to 3 days (group 2), 1 week (group 3), and 6 weeks (group 4) of indomethacin treatment.

MAIN OUTCOME MEASUREMENTS

Factors analyzed included the overall incidence, Brooker class and volume of HO, radiographic union of the acetabular fracture, and pain. Patients were followed clinically and radiographically at 6 weeks, 3 months, 6 months, and 1 year. Serum levels of indomethacin were drawn at 1 month to assess compliance. Computed tomographic scans were performed at 6 months to assess healing and volume of HO.

RESULTS

Ninety-eight patients were enrolled into this study, 68 completed the follow-up and had the 6-month computed tomographic scan, and there was a 63% compliance rate with the treatment regimen. Overall incidence of HO was 67% for group 1, 29% for group 2 (P = 0.04), 29% for group 3 (P = 0.019), and 67% for group 4. The volume of HO formation was 17,900 mm for group 1, 33,800 mm for group 2, 6300 mm for group 3 (P = 0.005), and 11,100 mm for group 4. The incidence of radiographic nonunion was 19% for group 1, 35% for group 2, 24% for group 3, and 62% for group 4 (P = 0.012). Seventy-seven percent of the nonunions involved the posterior wall segment. Pain visual analog scores (VASs) were significantly higher for patients with radiographic nonunion (VAS 4 vs. VAS 1, P = 0.002).

CONCLUSIONS

Treatment with 6 weeks of indomethacin does not appear to have a therapeutic effect for decreasing HO formation after acetabular fracture surgery and appears to increase the incidence of nonunion. Treatment with 1 week of indomethacin may be beneficial for decreasing the volume of HO formation without increasing the incidence of nonunion.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Bone turnover markers failed to predict the occurrence of osteonecrosis of the femoral head: a preliminary study

BACKGROUND

The early detection of osteonecrosis of the femoral head (ONFH) is difficult, but important for prevention of destruction of the femoral head. The objective of this study was to determine whether the occurrence of osteonecrosis of the femoral head (ONFH) correlates with changes in bone turnover markers.

METHODS

In 40 patients undergoing primary total hip arthroplasty (THA), different bone turnover markers and hormones (bone specific alkaline phosphatase, osteocalcin, beta cross-laps, 25-hydroxy-cholecalciferol, and parathormone) gained from blood were determined on the morning of the surgery. Twenty-two patients needed a THA due to progressed ONFH. In 18 cases blood was gained from patients with the indication for a THA given due to advanced osteoarthritis (AO) of the hip.

RESULTS

Bone specific alkaline phosphatase, osteocalcin, beta cross-laps, and parathormone did not show any deviation from standard values, neither for the group of osteonecrosis nor for the osteoarthritis group. 25-Hydroxy-cholecalciferol revealed on average decreased values without significant differences between both groups (P < 0.05). The tested bone turnover markers and hormones failed to predict the occurrence of ONFH. Thus, the focus has to be put on different parameters to find a specific parameter that possibly predicts the risk of ostenecrosis and that is suited to follow up ONFH.

Risk factors for heterotopic ossification in primary total hip arthroplasty

Heterotopic ossification (HO) is a recognised complication of total hip arthroplasty (THA). This study aims to correlate demographics, surgical approach and type of arthroplasty to the incidence of HO in an attempt to quantify patient risk. A total of 920 primary THAs in 893 patients were performed between 2006 and 2008 in a single arthroplasty centre. Radiographic evaluation was conducted and all cases of HO were classified using the Brooker classification. Age, sex, arthroplasty type and surgical approach were all considered as variables. Arthroplasty type was classified into four groups; total cemented (TC), total uncemented (TU), hybrid (H) and reverse hybrid (RH). Two-level logistic regression analysis was conducted. The overall incidence of HO was 24%. Male sex [OR=3.57, 95% CI (1.79-7.10); p=0.001], lateral approach [OR=2.47, (95% CI 1.23-4.95); p=0.001] and total cemented implants [OR=3.14, (95%CI 1.37-7.23); p=0.007] were significantly associated with HO. The intra-class correlation coefficient was 0.52 [95% CI (0.21, 0.81); p=0.004], demonstrating that patients with previous HO to one THA were very likely to suffer HO in subsequent THA. The results demonstrate very large effects for sex, surgical approach, and implant type on HO incidence. This raises a three arm hypotheses that reaming of the femoral canal for the insertion of cemented implants contaminates the surgical field with bone marrow increasing the risk of HO, whereas modern cementless implants generally employ impaction broaching. In addition surgical insult to the hip abductors during exposure, particularly in males due to higher muscle mass, may also predispose to HO.

[Heterotopic ossifications in total hip arthroplasty: prophylaxis and therapy]

Heterotopic ossification (HO) is a frequent and occasionally severe complication after total hip arthroplasty. Clinical symptoms of this benign abnormal bone formation are loss of mobility and local pain. The etiology and pathomechanisms are not yet completely understood. Overexpression of bone morphogenetic proteins and dysregulation of prostaglandin metabolism seem to be relevant. Medication with non-steroidal anti-inflammatory drugs (NSAIDs) and perioperative single dose radiotherapy are used for prophylaxis, whereby radiotherapy should only be performed in patients with a history of HO or additionally after resection of HO. From currently available data selective cyclooxygenase-2 inhibitors seem to have a preventive efficacy equal to the classical NSAIDs diclofenac and indometacin. This work discusses current knowledge about the pathophysiology, risk factors and the clinical approach for prevention and treatment of HO.

Does a plastic drape reduce incidence of heterotopic ossification after hip resurfacing?

BACKGROUND

High rates of heterotopic ossification have been associated with hip resurfacing as compared to THA. Bone debris from femoral head reamings is cited as one of the risk factors linked to increased rates of heterotopic ossification.

QUESTIONS/PURPOSES

We therefore asked whether (1) the incidence of heterotopic ossification differed with and without the use of a plastic drape used to collect bone debris and (2) any of a number of variables (age, gender, diagnosis, previous hip surgery, operative time, and blood loss) related to the occurrence of HO.

METHODS

We retrospectively reviewed 136 hip resurfacings performed using one of two techniques: Group 1 contained 64 hip resurfacings performed using a sterile drape around the femoral neck while reaming the femoral head to collect bone debris; Group 2 contained 72 hip resurfacings carried out with manually removing bone debris and utilizing a pulse lavage. Data were collected with respect to diagnosis, gender, previous surgery, postoperative complications, operative time, and blood loss to rule out confounding variables. The amount of heterotopic ossification was measured radiographically in hips after undergoing resurfacing arthroplasty. The minimum followup was 6 months (mean, 15 months; range, 6-27 months).

RESULTS

No patient had heterotopic ossification of clinical importance and none had resection of the heterotopic ossification. Group 1 had a lower overall incidence of minor heterotopic ossification (32%) than Group 2 (58%). Risk factors linked to heterotopic ossification include male gender and operative time.

CONCLUSIONS

The use of a plastic drape to collect bone debris from femoral head reamings decreased the incidence of heterotopic ossification in resurfacing arthroplasty of the hip.

Biomarkers in arthroplasty: a systematic review

We performed a systematic review of all MEDLINE-published studies of biomarkers in arthroplasty. Thirty studies met the inclusion criteria; majority evaluated biomarkers for osteolysis, aseptic prosthetic loosening, and prosthetic infections. Four studies reported an elevated Cross-linked N-telopeptides of type I collagen (urine or serum) in patients with osteolysis or aseptic prosthetic loosening when compared to appropriate controls. Two or more studies each found elevated C-reactive protein, erythrocyte sedimentation rate, and interleukin-6 in patients with infected prosthetic joints compared to controls. Most other biomarkers were either examined by single studies or had inconsistent or insignificant associations with outcomes. We conclude that the majority of the biomarkers currently lack the evidence to be considered as biomarkers for arthroplasty outcomes. Further studies are needed.

Heterotopic ossification after cervical total disc replacement: determination by CT and effects on clinical outcomes

OBJECT

Heterotopic ossification (HO) after cervical total disc replacement (TDR) has been reported to impede artificial disc motion. In all previously reported cases of HO, assessment was based on plain radiographs. The authors hypothesized that CT scan is a more sensitive and accurate detector. The aims of this study were to assess the actual incidence of HO and its effect on outcome in a cohort of patients undergoing cervical TDR with the Bryan disc and to compare HO detection by means of plain radiographs and CT.

METHODS

The authors retrospectively assessed data from medical records, radiological studies, and clinical evaluations of patients who underwent 1- or 2-level cervical TDR with the Bryan disc and were followed up for more than 12 months. The presence and grading of HO according to the McAfee classification were assessed by CT scan, and these findings were compared with findings on plain radiographs. Thirty-six patients (mean age 46.61 ± 7.24 years; range 29-60 years; 21 men and 15 women) who underwent Bryan TDR at 52 levels were included in the study. The mean duration of CT follow-up was 19.03 ± 4.64 months; the mean duration of clinical follow-up was 26.78 ± 7.20 months.

RESULTS

On the basis of CT, HO was identified in 18 (50%) of 36 patients and 25 (48.1%) of 52 levels treated. Grade 1 HO was present in 9 of the levels treated (17.3%), Grade 2 in 13 levels (25.0%), Grade 3 in 2 levels (3.8%), and Grade 4 in 1 level (1.9%). Nineteen (76%) of the 25 affected levels were in patients who had undergone 2-level TDR. There was no significant association with patient sex or disc pathology. There was a tendency for HO development among older patients, but this finding was not statistically significant (mean age 48.8 ± 6.8 in patients with HO vs 44.4 ± 7.2 in those without HO, p = 0.065). Although HO was found in 25 levels, 96.2% of the treated levels (50 of 52) had segmental range of motion on dynamic (flexion and extension) radiographs. The concordance between HO grading by CT and radiography was high, with an intraclass correlation coefficient of 0.822 (lower limit of 95% CI: 0.710, p < 0.001). Patients who had HO had the same clinical success rate as those who did not (94.4% vs 94.4%, p = 1.00). The visual analog scale scores for neck and arm pain were significantly improved in both the HO and the non-HO group.

CONCLUSIONS

The rate of HO detected by CT scan in this cohort of patients undergoing cervical TDR with a Bryan disc was 48.1% per level treated and 50% per patient with minimal limitation of segmental motion (96.2% of levels remained mobile), but plain radiograph is an acceptable detection tool. Two-level surgery has a higher risk of HO, although development of HO does not affect clinical outcome.

Heterotopic ossification after 2-incision total hip arthroplasty

We examined the incidence of heterotopic ossification (HO) in a consecutive series of total hip arthroplasties (THAs) performed with the so-called minimally invasive, 2-incision technique. Standard preoperative hip radiographs were used to grade the extent of degenerative arthritis, and comparable follow-up radiographs at 30 months after surgery were used to detect and classify HO formation. Of 121 patients, 32 (26.5%) developed HO, with the Brooker class distribution as follows: stage I, 16 patients; stage II, 9 patients; stage III, 6 patients; stage IV, 1 patient. In this study, HO formation after 2-incision THA occurred with nearly the same frequency as that reported in other studies after standard THA.

Levothyroxin inhibits heterotopic ossification: an experimental study in rabbits

BACKGROUND

Heterotopic ossification is a common complication of surgery or trauma.

OBJECTIVE

To investigate the efficacy of levothyroxin in inhibition of heterotopic ossification.

METHODS

Heterotopic ossification was induced in 36 rabbits in three identical groups by injecting 2 mL of bone marrow in right thigh. To prevent heterotopic ossification, levothyroxin (20 microg/kg) was administered orally daily for 4 weeks to two groups of adult rabbits: group A (preload)--starting 1 week preceding bone marrow injection; group B--started on day of injection; and group C--control group (no levothyroxin) in a rabbit model. After 5 weeks the rabbits were evaluated by radiographs for evidence of ossification. At the end of the study histologic samples were taken from all the thighs.

RESULTS

Imaging and histologic studies showed, with statistical significance, almost complete prevention of heterotopic ossification in group A (preload) and a marked decrease in group B, when compared with the controls.

CONCLUSIONS

Levothyroxin demonstrated efficacy in preventing heterotopic ossification.

Impact of trochanteric heterotopic ossification on measurement of femoral bone density following cemented total hip replacement

During a study of bone mineral density changes around cemented femoral implants, we recognized heterotopic ossification occurring regularly in a position anterior to the greater trochanter and proximal femur. The aim of this study was to describe the incidence, distribution, and effect of this ossification on periprosthetic DXA scans following primary cemented total hip replacement. One hundred eleven patients underwent postoperative DXA examinations measuring changes in bone mineral density with heterotopic ossification identified and localized on standard radiographs with confirmation using DXA subtraction imaging. Male gender and age within the male group were significantly associated with occurrence of heterotopic ossification (p = 0.003 and 0.046, respectively). Femoral stem type, weight, and body mass index had no significant effect (p = 0.525, 0.372, and 0.243, respectively). Examining the Gruen zones in all patients suggested a median (plus interquartile range) zone 1 density drop of 4% (-12% to +7%). When separated and analyzed for the effect of heterotopic ossification, the 45 patients with heterotopic ossification showed a 2-year density gain of +6% (-5% to +15%), whereas those without heterotopic ossification showed a loss of 8% (-14% to 0%), a significant difference (p < 0.001). Zone 2 also showed a significant difference (p = 0.048). We therefore recommend that affected zones should be identified and excluded from analysis at all time points. Without this precaution, researchers risk underestimating periprosthetic bone loss in their studies and reporting misleading conclusions.

The prophylaxis and treatment of heterotopic ossification following lower limb arthroplasty

Heterotopic ossification following joint replacement in the lower limb occurs in 3% to 90% of cases. Higher grades of heterotopic ossification can result in significant limitation of function and can negate the benefits of joint replacement. The understanding of the pathophysiology of this condition has improved in recent years. It would appear to be related to a combination of systemic and local factors, including over-expression of bone morphogenetic protein-4. There is currently little evidence to support the routine use of prophylaxis for heterotopic ossification in arthroplasty patients, but prophylaxis is recommended by some for high-risk patients. Radiotherapy given as one dose of 7 Gy to 8 Gy, either pre-operatively (< four hours before) or post-operatively (within 72 hours of surgery), appears to be more effective than indometacin therapy (75 mg daily for six weeks). In cases of prophylaxis against recurrent heterotopic ossification following excision, recent work has suggested that a combination of radiotherapy and indometacin is effective. Advances in our understanding of this condition may permit the development of newer, safer treatment modalities.

A comparative analysis of phenotype expression in human osteoblasts from heterotopic ossification and normal bone

BACKGROUND AND AIMS

Heterotopic ossification (HO) is a pathological bone formation process in which ectopic bone is formed in soft tissue. The formation of bone depends on the expression of the osteoblast phenotype. Earlier studies have shown conflicting results on the expression of phenotype markers of cells originating from HO and normal bone. The hypothesis of the present study is that cells from HO show an altered expression of osteoblast-specific phenotype markers compared to normal osteoblasts. The aims of the study were to further characterize the expression of osteoblast phenotypemarkers and to provide a comparison with other study results.

PATIENTS AND METHODS

Using an in vitro technique, reverse transcription polymerase chain reaction (RT-PCR), real-time PCR and immunohistochemistry, we compared the phenotype gene expression (type I collagen, alkaline phosphatase, Cbfa-1, osteocalcin) of osteoblasts from resected HO and normal bone (iliac crest).

RESULTS

Cells from HO expressed the osteoblast phenotype (type I collagen, alkaline phosphatase) but were characterized by a depleted osteocalcin expression. The expression of Cbfa-1 (osteocalcin transcription gene) showed a large variety in our study. Preoperative radiotherapy had no effect on phenotype expression in cells from HO.

CONCLUSION

Our results provide a characterization of cells originating from HO and support the thesis of an impaired osteoblast differentiation underlying the formation of HO. The transcription axis from Cbfa-1 to osteocalcin could be involved in the pathogenesis of HO.

Prevention of heterotopic ossification in high-risk patients with total hip arthroplasty: the experience of a combined therapeutic protocol

The combination of radiotherapy and indomethacin for the prevention of heterotopic ossification (HO) in high-risk patients undergoing total hip arthroplasty (THA) has not been reported. The aim of the present study was to present the experience of our department with this combined therapeutic protocol. Fifty-four patients who underwent THA received a single dose of 7 Gy of postoperative radiotherapy and 75 mg of indomethacin for 15 days. Patients were analyzed for clinical and radiographical evidence of HO development at 1 year postoperatively. The overall radiographical incidence of HO was 20.4% (95% CI 10.6-33.5%), while only 1 patient with clinically significant HO was seen. Patients with secondary arthritis due to congenital hip disease had a statistically significantly higher incidence of HO compared with those with osteoarthrosis. The clinical assessment with the Merle d'Aubigné score showed that patients with radiographic documentation of HO had a lower mean score compared with those with no evidence of HO. No treatment-related side effects were seen. Combined radiotherapy and indomethacin was effective in preventing heterotopic ossification after total hip arthroplasty. The evaluation of this efficacy compared with radiotherapy or NSAIDs alone should be the future target of larger randomized designs.

Amino-bisphosphonates in heterotopic ossification: first experience in five consecutive cases

STUDY DESIGN

Retrospective, observational study in five consecutive cases.

OBJECTIVES

The management of heterotopic ossification (HO), a frequent complication after spinal cord injury (SCI) and after orthopaedic surgery, is a therapeutic challenge with high recurrence rates of over 50%. Conflicting data were reported for Etidronate. The use of the more potent new generation of amino-bisphosphonates has been put forward in different inflammatory, dysmorphogenic bone disease. In order to try and halt the underlying dysfunctional bone metabolism we have studied the action of pamidronate in five consecutive high-risk patients with established HO of different etiology undergoing surgical removal.

SETTING

University Hospital of Basel, Switzerland, Division of Endocrinology, Diabetology and Clinical Nutrition and the Department of Orthopedic Surgery.

METHODS

In all five patients, ranging from 47 to 68 years of age, we used continuous pamidronate infusions perioperatively at a dosage of 120 mg in the first 12 h and subsequent reduction to 75-60-30-15 mg/12 h over a period of 10-14 days.

RESULTS

None of these patients showed clinical, radiographical and laboratory signs of HO recurrence or new forming HO in the follow-up 5-54 month after surgery. Potential side effects of high-dose bisphosphonate therapy such as osteoporosis and osteomalacia were not reported in any case.

CONCLUSION

We postulate that pamidronate might have pronounced beneficial effects in high-risk patients with established HO undergoing excision surgery. Since the therapeutic window of amino-bisphosphonates has not yet been defined and the minimal necessary doses for preventing new HO are unknown, further studies are encouraged to confirm our findings and to identify the necessary dosage and duration of treatment and to pinpoint, which patients will benefit most from this treatment.

Radiotherapy vs. nonsteroidal anti-inflammatory drugs for the prevention of heterotopic ossification after major hip procedures: a meta-analysis of randomized trials

PURPOSE

To evaluate the efficacy of radiotherapy (RT) vs. nonsteroidal anti-inflammatory drugs (NSAIDs) in the prevention of heterotopic ossification (HO) after major hip procedures.

METHODS AND MATERIALS

We conducted a meta-analysis of 7 randomized studies (n = 1143) comparing RT with NSAIDs. Data were combined across studies using fixed and random effects models. We conducted separate analyses for clinically significant HO (Brooker Grade 3 and 4) and for any HO (any Brooker grade).

RESULTS

Overall RT tended to be more effective than NSAIDs in preventing Brooker 3 or 4 HO (risk ratio, 0.42; 95% confidence interval [CI], 0.18-0.97) or any HO (risk ratio, 0.75; 95% CI, 0.37-1.71), but with significant between-study heterogeneity for the second analysis. The overall absolute risk difference for Brooker 3 or 4 HO was small (-1.18%; 95% CI, -2.45% to 0.09%). Subgroup analyses showed that early preoperative RT (16-20 hours before surgery) and acetylsalicylic acid were less effective. For postoperative RT, there was a significant dose-response relationship (p = 0.008): 6 Gy of RT was equally effective as NSAIDs, whereas increasing radiation doses were more effective.

CONCLUSIONS

Although absolute differences may be small, postoperative RT is on average more effective than NSAIDs in preventing HO after major hip procedures, and its efficacy is dose dependent.

Gene expression in human osteoblastic cells from normal and heterotopic ossification

Heterotopic ossification (HO), a possible complication of head injury, develops in sites where it is not normally present like at the vicinity of joints. It may cause pain, decrease motion and in severe cases complete joint ankylosis requiring surgical intervention. To our knowledge, no study has been made to analyze HO at the molecular level on human biopsies, whereas its etiology remains to be determined. We defined a procedure of cell fractionation from bone resections and developed quantitative RT-PCR to compare genetic expression patterns between human normal osteoblasts and heterotopic ossification forming cells. This quantitative study demonstrated a specific and strong overexpression of osteocalcin mRNA in HO-isolated cells associated with a significant upregulation of type 1 collagen and osteonectin mRNA while histological analysis showed only small cellular variations. Our results give a first molecular characterization of heterotopic ossification and we conclude that such overexpressions in HO-isolated cells could be associated with the high activity of this pathological bone.