PREVENTION OF HETEROTOPIC OSSIFICATION AFTER TOTAL HIP REPLACEMENT

Role of aspirin in the prevention of heterotopic ossification following total hip replacement: a systematic review and meta-analysis

BACKGROUND

To systematically investigate if aspirin (ASA), used as venous thromboembolism (VTE) prophylaxis, plays a role in the prevention of heterotopic ossification (HO) following total hip arthroplasty (THA) and if ASA dosage impacted the rate of HO.

METHODS

Eligible studies published from January 2000 to July 2022 were identified from the computerized searching of PubMed, Scopus and Web of Science. HO was defined according to Brooker Classification. Pooled risk ratios (OR) and 95% confidence interval (CI) were estimated under a random-effect model. Additionally, combined HO incidences were compared according to ASA dosage (a regular dose of 325 bid vs. a low dose of 81 mg bid/162 mg qd).

RESULTS

Thirteen studies were included. ASA administered for VTE prophylaxis was significantly associated with a reduced risk of all-grade HO following THA (univariate, OR: 0.50, 95% CI: 0.34-0.74, P < 0.001; multivariate, OR: 0.60, 95% CI: 0.49-0.73, P < 0.001). Similar results could be observed for high-grade HO (univariate, OR: 0.57, 95% CI: 0.36-0.89, P = 0.015; multivariate, OR: 0.50, 95% CI: 0.27-0.92, P = 0.026). There was a non-significant trend towards a higher incidence of HO formation for low-dose ASA (31%, 95% CI: 29-34%), compared with regular-dose ASA (21%, 95% CI: 11-33%) (P = 0.069 under test of interaction).

CONCLUSIONS

ASA can be an effective option for HO prophylaxis. More well-designed trials with long-term follow-ups are encouraged to confirm the current findings and to investigate the effect of ASA dosage on HO reduction.

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.

Is Heterotopic Ossification Associated With Surgical Approach in Total Hip Arthroplasty?

BACKGROUND

Although risk factors for heterotopic ossification (HO) have been defined, the effect from surgical approach is not fully understood. The primary objective of our study was to evaluate the effect that surgical approach has on the risk for developing severe HO after total hip arthroplasty (THA) and compare this with other known risk factors. We hypothesized that there would be no difference in HO formation based on the surgical approach.

METHODS

We retrospectively reviewed all patients who underwent primary THA at our hospital between March 2011 and March 2021. Patients with HO documented in the radiology reports were cross-referenced with our THA data set and manually reviewed to determine Brooker classification. Patient demographics, medical comorbidities, surgical details, and medication information were collected from the electronic medical record and compared.

RESULTS

Of 3,427 patients who underwent THA, 677 (19.8%) developed HO postoperatively. A multivariable analysis confirmed that surgical approach was independently associated with increased odds for HO development. The anterolateral (odds ratio [OR], 3.43; P < 0.001) and posterior (OR, 2.24; P < 0.001) approaches had increased odds for developing HO compared with the direct anterior approach. However, only the anterolateral approach (OR, 1.85; P = 0.033) demonstrated an increased association with the development of severe HO (Brooker 3, 4) postoperatively.

CONCLUSION

Although the use of the direct anterior approach had the lowest overall OR for developing HO after THA, this is likely only clinically notable when compared with the anterolateral approach.

LEVEL OF EVIDENCE

III.

Efficacy of NSAIDs versus radiotherapy for heterotopic ossification prophylaxis following total hip arthroplasty in high-risk patients: a systematic review and meta-analysis

BACKGROUND

The aims of this systematic review were: (1) to investigate the prophylactic effect of radiotherapy (RT) and NSAIDs in high-risk patients following total hip arthroplasty (THA); and (2) to compare the efficacy of non-selective and COX-II selective NSAIDs in preventing post-THA HO, utilising a meta-analysis of randomised control studies.

METHODS

The PubMed, Embase, and Cochrane Databases were searched for articles regarding HO following THA in March 2019. Studies were included if they contained data regarding HO incidence after THA or contained data regarding HO prophylaxis comparison of NSAIDs and/or RT in terms of dosage or duration.

RESULTS

24 studies reported on populations that were not at high-risk for HO. These studies reported between 47.3% and 90.4% of their patient populations had no HO formation; between 2.8% and 52.7% had mild formation; and between 0.0% and 10.4% had severe formation. A total of 13 studies reported on populations at high-risk for HO. Studies analysing RT in high-risk patients reported between 28.6% and 97.4% of patients developed no HO formation; between 1.9% and 66.7% developed mild HO formation; and between 0.0% and 11.9% developed severe HO formation. Studies analysing NSAID treatment among high-risk populations reported between 76.6% and 88.9% had no HO formation; between 11.1% and 23.4% had mild HO formation, and between 0.0% and 1.8% had severe HO formation. 9 studies were identified as randomised control trials and subsequently used for meta-analysis. The relative risk for COX-II in developing any HO after THA was not significantly different compared to non-selective NSAIDs (RR 1.00; CI, 0.801-1.256; p = 0.489).

CONCLUSIONS

NSAIDs prophylaxis for HO may have better efficacy than RT in high-risk patients following THA. Non-selective and COX-II selective NSAIDs have comparable efficacy in preventing HO. Factors such as medical comorbidities and side-effect profile should dictate the prophylaxis recommendation.

Identification of Risk Factors in the Development of Heterotopic Ossification After Primary Total Hip Arthroplasty

PURPOSE

Heterotopic ossification (HO) is a process by which bone forms abnormally in soft tissues. Known risk factors for developing HO include male sex, spinal cord injury, trauma, and surgery. We investigated additional risk factors in the development of HO after hip arthroplasty.

METHODS

We performed a retrospective review of electronic medical records of 4070 individuals who underwent hip arthroplasty from September 2010 to October 2019 at the University of California, San Francisco Hospital. Demographics, anthropometrics, medications, and comorbid conditions were used in logistic regression analysis to identify factors associated with the development of HO.

RESULTS

A total of 2541 patients underwent primary hip arthroplasty in the analyzed timeframe (46.04% men, mean age at procedure: 62.13 ± 13.29 years). The incidence of postsurgical HO was 3% (n = 80). A larger proportion of individuals who developed HO had underlying osteoporosis (P < 0.001), vitamin D deficiency (P < 0.001), spine disease (P < 0.001), type 1 or 2 diabetes (P < 0.001), amenorrhea (P = 0.037), postmenopausal status (P < 0.001), parathyroid disorders (P = 0.011), and history of pathologic fracture (P = 0.005). Significant predictors for HO development were Black/African American race [odds ratio (OR) 2.97, P = 0.005], preexisting osteoporosis (OR 2.72, P = 0.001), spine disease (OR 2.04, P = 0.036), and low estrogen states (OR 1.99, P = 0.025). In the overall group, 75.64% received perioperative nonsteroidal anti-inflammatory drugs (NSAIDs), which negatively correlated with HO formation (OR 0.39, P = 0.001).

CONCLUSIONS

We identified new factors potentially associated with an increased risk of developing HO after primary hip arthroplasty, including African American race, osteoporosis, and low estrogen states. These patients may benefit from HO prophylaxis, such as perioperative NSAIDs.

A comprehensive update on the pharmacological management of heterotopic ossification following hip arthroplasty: a level I evidenced based expert opinion

INTRODUCTION

Heterotopic ossification (HO) of the hip joint may happen accompanying skeletal muscle trauma or surgical procedures. The pharmacological prophylaxis of heterotopic ossification (HO) following total hip arthroplasty (THA) is debated.

AREAS COVERED

This expert opinion aims to systematically investigate the efficacy of current pharmacological options as prophylaxis for HO following THA.

EXPERT OPINION

The current evidence identified celecoxib, naproxen, and diclofenac as best option for the prevention of HO in patients who undergo primary THA. The most appropriate pharmacotherapy for the prevention of HO is still debated and should be customized according to patients' comorbidities and medical history. For patients with cardiovascular comorbidities, naproxen, or diclofenac should be considered along with proton pump inhibitors to prevent gastrointestinal complications. For patients with history of gastrointestinal disease, celecoxib can be recommended. These conclusions must be considered within the limitations of the present investigation. Between studies, heterogeneities in the administration protocols were evident. In some RCTs, the length of the follow-up was shorter than 12 months. The current clinical practice would benefit of high-quality recommendations and the development of the shared official guidelines.

Diclofenac for prophylaxis of heterotopic ossification after hip arthroplasty: a systematic review

BACKGROUND

Heterotopic ossification (HO) is defined as the formation of lamellar bone in extraskeletal soft tissues. HO can be a severe complication after hip arthroplasty but can possibly be prevented by postoperative treatment with non-steroidal anti-inflammatory drugs (NSAIDs) or radiotherapy. Diclofenac is 1 of the most used drugs in HO prophylaxis because it is effective and long established. However, there is still no uniform therapy regimen in terms of duration, dose and side effect profile regarding the application of diclofenac in HO prevention. We have, therefore, conducted the first systematic review investigating diclofenac for HO prophylaxis after hip arthroplasty. The aim of this study is to assess the efficacy, dose and duration of diclofenac therapy in preventing HO after total hip arthroplasty (THA).

METHODS

According to the PRISMA Guidelines we performed a systematic literature search in EMBASE via Ovid, in MEDLINE via PubMed and in the Cochrane Library addressing all studies in English and German regarding the prophylaxis of HO with diclofenac after THA. We identified 731 potential studies and included 6 randomised controlled trials with 957 patients.

RESULTS

The studies were heterogeneous with regard to duration of therapy, dose, comparative group and follow-up period. The therapy duration ranged from 9 to 42 days, the applied diclofenac doses ranged from 75 mg to 150 mg daily. Patients treated with diclofenac showed a significant reduction in the total incidence of HO regarding to the Brooker Classification compared to placebo and no clinically relevant ossifications occured (Brooker III and IV).

CONCLUSIONS

Diclofenac is efficacious in the prevention of HO and can be used routinely after THA. The existing data indicates that a minimum dose of 75 mg diclofenac per day started on the first postoperative day for a minimum of 9 days is needed to prevent HO with an acceptable incidence of side effects, such as gastrointestinal symptoms.

Low-dose Preoperative Unshielded Radiation Is Effective in Heterotopic Ossification Prophylaxis and Does Not Affect Porous Fixation in Total Hip Arthroplasty at 2 Years Minimum Follow-up: A Radiographic Study

BACKGROUND

Heterotopic ossification (HO) is a frequent complication of total hip arthroplasty (THA). HO can cause pain, limitation of range of motion, and instability. Radiation therapy (RT) for HO prophylaxis is well established but may interfere with early porous ingrowth and pullout strength of implants, as suggested by two animal studies. Although shielding of the bone from irradiation may theoretically protect ingrowth, it has been found to reduce RT effectiveness. Despite the popularity of porous implants in THA, the frequency of HO, and use of RT in its prophylaxis, the effect of RT on porous implant fixation in THA has not been previously reported. At our institution, we use unshielded, single-dose, preoperative 700 to 800 centigrays RT for HO prophylaxis in high-risk patients. We hypothesize that this RT protocol is effective and the press-fit technique protects porous implants during early ingrowth; therefore, long-term implant fixation is not compromised.

METHODS

This was a retrospective study aiming to determine fixation of porous THA implants, healing of trochanteric osteotomies, and efficacy of HO prophylaxis with this RT protocol.

RESULTS

Thirty-nine patients with follow-up of 24 to 144 months (average 59.7 months) were included. All 26 porous-coated femoral implants (11 revisions and 15 primary) were well fixed. There were 33 porous-coated acetabular implants (18 revisions and 15 primary). Thirty (91%) were well fixed, and three revision implants (9%) demonstrated radiolucent lines in two zones, but patients were clinically asymptomatic. All nine trochanteric osteotomies healed uneventfully. RT provided effective HO prophylaxis in 33 of 39 hips (85%).

CONCLUSIONS

Single, low-dose, preoperative RT without shielding does not increase aseptic loosening of porous implants manufactured with plasma porous spray or nonunion of extended trochanteric osteotomies. This protocol provides effective HO prophylaxis in high-risk patients undergoing primary and revision THA.

Synostosis of the interphalangeal joint: an uncommon cause of post-fracture digital stiffness

Loss of motion and stiffness after fracture of the digits are most commonly a result of soft tissue contracture and adhesions. However, stiffness can also have a bony etiology. We present a case of synostosis of the thumb interphalangeal joint after non-operative treatment of a closed fracture.

Low-Dose Aspirin Administered for Venous Thromboembolism Prophylaxis Reduces the Incidence of Heterotopic Ossification in Total Joint Arthroplasty

BACKGROUND

Heterotopic ossification (HO) is a common complication following total joint arthroplasty (TJA). However, the pathophysiology of HO is not entirely understood. Inflammation may play a significant role in the pathogenesis of HO as nonsteroidal anti-inflammatory drugs are effective in the prevention of HO. The purpose of this study is to examine if aspirin (ASA), when used as venous thromboembolism (VTE) prophylaxis, influenced the rate of HO formation following TJA.

METHODS

We queried our longitudinally maintained database to identify all patients who underwent primary total hip arthroplasty (THA) or total knee arthroplasty (TKA) for osteoarthritis between January 2016 and June 2018 with at least 3-month radiographic follow-up. In total, 1238 THAs and 1051 TKAs were included for analysis. Radiographs were reviewed and HO formation graded according to the Brooker classification. Patient demographic and VTE prophylaxis data were collected and reviewed for accuracy. Univariate and multivariate analysis was performed to evaluate the effect of ASA on HO formation.

RESULTS

The overall rate of HO was 37.5% after THA and 17.4% after TKA. Patients receiving ASA were less likely to develop HO after THA (34.8% vs 45.5%; P < .001), as well as HO after TKA (13.4% vs 18.4%; P = .047) compared to patients receiving non-ASA VTE prophylaxis. The rate of HO formation trended to be lower, albeit not statistically significantly, in patients receiving low-dose ASA (81 mg) vs high-dose ASA (325 mg).

CONCLUSION

Patients undergoing primary TJA receiving ASA for VTE prophylaxis were less likely to develop HO compared to patients who were administered non-ASA VTE prophylaxis.

Radiotherapy for the prophylaxis of heterotopic ossification after total hip arthroplasty: A systematic review and meta-analysis of randomized controlled trails

Heterotopic ossification (HO) refers to the formation of lamellar bone in soft tissues and is a significant complication after total hip arthroplasty (THA). Radiotherapy has been proven as an effective prophylaxis especially for those patients with high risk of HO after THA. However the dose, timing, and frequency of radiation have yet to be determined. To compare HO progressions with different radiotherapy strategies and explore an optimal radiation option. We systematically searched PubMed, Embase, and Cochrane Library for randomized controlled trails (through December 1, 2019; no language restrictions) collecting patients who accepted prophylaxis radiation for whom HO progression outcomes were reported. Of 87 identified studies, 10 randomized controlled trails including 1203 patients and 1268 hips were taken to this analysis. Compared with the low biologically effective radiation dose group (biologically effective dose [BED] < 20 Gy), the medium biologically effective radiation dose group (20 Gy ≤ BED ≤ 24 Gy) had statistically significant difference on the prophylaxis of HO (p = 0.003). But for overall incidence of HO, there was no statistically significant difference between low BED group and high BED group (BED > 24, p = 0.21). There was statistically significant reduction in the prophylaxis of HO progression with multiple fractions as opposed to single fraction radiotherapy (p = 0.04). Hips with preoperative radiation were no more likely to observe HO progression than those with postoperative radiotherapy (p = 0.43). Radiotherapy with medium dose (20 Gy ≤ BED ≤ 24 Gy) after THA is an effective dose for preventing HO. In the prophylaxis of HO, multiple fractions seem to be more effective than single fraction radiation. Preoperative radiotherapy could prevent HO progression with the same efficacy postoperative.

Aspirin used for venous thromboembolism prophylaxis in total hip arthroplasty decreases heterotopic ossification

Background

Heterotopic ossification (HO) is a known complication of total hip arthroplasty (THA) that can lead to persistent pain, stiffness, nerve impingement, and instability. Aspirin (ASA) has become an increasingly popular method of venous thromboembolism (VTE) prophylaxis, given its availability, ease of use, and relative safety. Although indomethacin has been commonly used for HO prophylaxis, we wanted to determine whether ASA, given the similar mechanism of action, may be effective in reducing the risk of HO in routine unilateral, primary THA when already being used for VTE prophylaxis.

Methods

The postoperative radiographs of 222 consecutive patients undergoing unilateral, primary THA with cementless fixation were evaluated for HO formation using the Brooker classification immediately before and after surgeon protocol shifted to routine utilization of ASA as VTE prophylaxis in low-risk patients.

Results

HO was detected in 13 of 99 (13.1%) THAs prescribed ASA for VTE prophylaxis (11 grade I, 1 grade II, 1 grade III) compared with 38 of 123 (30.9%) THAs prescribed non-ASA chemoprophylaxis (26 grade I, 7 grade II, 4 grade III, 1 grade IV). Significantly more THAs in the non-ASA cohort developed HO (P < .01). There was no significant difference in the distribution of HO severity between cohorts (P = .61).

Conclusions

ASA may be effective as monotherapy for both VTE and HO reduction in low-risk patients undergoing unilateral primary arthroplasty with cementless fixation.

Optimal strategies for the prevention of heterotopic ossification after total hip arthroplasty: A network meta-analysis

BACKGROUND

Nonselective nonsteroidal anti-inflammatory drugs (NSAIDs), selective NSAIDs, and radiation are widely used for the prevention of heterotopic ossification (HO) after total hip arthroplasty (THA). Previous studies have suggested that nonselective NSAIDs, selective NSAIDs and radiation can prevent HO after THA, though the results are conflicting. In this network meta-analysis, we aimed to comprehensively analyze the efficacy and safety of three strategies for preventing HO after THA compared to a placebo.

PATIENTS AND METHODS

Relevant studies about nonselective NSAIDs, selective NSAIDs, radiation and controls that were used to prevent HO after THA were collected. Data were extracted independently by two reviewers. Network meta-analysis was applied to assess treatment efficacy and safety. The surface under the cumulative ranking curve (SUCRA) method was used to assess which treatment was ranked the highest. The node-splitting method was used to calculate inconsistency.

RESULTS

Radiation was found to be the most efficient option for preventing overall incidence of HO and Brooker IV, I, II and III HO after THA. Selective NSAIDs were the safest option, and radiation was ranked second for preventing HO after THA, as the treatments were ranked taking discontinuation caused by nongastrointestinal side effects (DNGSE) and the incidence of complications into consideration.

CONCLUSIONS

A network meta-analysis concluded that radiation is the most efficacious method for preventing HO after THA.

The clinical implications of heterotopic ossification in patients treated with radial head replacement for trauma: A case series and review of the literature

Radial head arthroplasty (RHA) is an acceptable treatment for comminuted radial head fractures (RHF). Fourteen patients with no postop HO prophylaxis were treated with RHA for comminuted RHF. A 50% incidence in HO was seen following RHA with a statistically increased risk (p ≤ 0.05) of reoperation compared to those without HO. Decreased ROM was seen on the affected side (p ≤ 0.05); patients without HO showed no statistical difference (p ≥ 0.05) in ROM or grip strength. HO following RHA increases patient risk for reoperation and decreases ROM. We recommend HO prophylaxis with NSAIDs and/or radiotherapy if no direct patient contraindications are found.

Postencephalitic bilateral heterotopic ossification of the hip in a pediatric patient

Heterotrophic ossification has been defined as abnormal formation of mature lamellar bone in soft tissues. Neurogenic heterotopic ossification has been well described in adults. However, it is uncommon in the pediatric population, where it has been noted to recede in some cases. There are very few reports of postmeningitis bilateral involvement of the hip. We describe a case of bilateral heterotopic ossification of hip in a 13-year-old female. The patient had a history of encephalitis, prolonged vegetative state, and intubation for 6 weeks. The patient had fixed deformities of both hips in 30° of flexion and 30° of external rotation. A diagnosis of Brooker stage 4 heterotopic ossification was made. The patient underwent a staged procedure for excision of the heterotopic mass. Postoperatively, the patient was administered radiotherapy and indomethacin for 6 weeks. At the 2-year follow-up, there was no recurrence and both the hips were mobile with full range of motion. The patient was satisfied with the result. The incidence of heterotopic ossification is less than that observed in the adult population and alkaline phosphatase levels are not significantly elevated unlike in adults. To our knowledge, there is no reported case of postencephalitic bilateral anterior heterotopic ossification of the hip in a pediatric patient treated with excision successfully. Postencephalitic heterotopic ossification in children is an uncommon condition. This condition can be treated successfully with surgical excision, combined postoperative protocol of radiotherapy, indomethacin, and immediate postoperative mobilization of the joint.

Proximal femoral resection for the painful dislocated hip in cerebral palsy: does indomethacin prevent heterotopic ossification?

BACKGROUND

Painful hip displacement is difficult to treat in severe cerebral palsy. Proximal femoral resection (PFR) is an excellent procedure for pain relief but has a high rate of heterotopic ossification (HO). Indomethacin is the gold standard therapy used for prevention in hip and acetabular surgery. There is no evidence of its benefit in this complex patient group.

METHODS

Forty-one consecutive patients with severe cerebral palsy underwent 52 primary PFRs for severe pain in 2 pediatric orthopaedic units in London, UK. Twenty-one patients received a prophylactic postoperative dose of indomethacin for the prevention of HO. Notes and radiographs were reviewed independently by 2 orthopaedic trainees.

RESULTS

The mean age of patients was 14.3 and 14.8 years in the group administered with and administered without indomethacin, respectively, and mean follow-up was 4.5 and 4.3 years. Five patients in each group developed HO. One patient in the indomethacin group was offered reexcision for HO but declined. Two in the nonindomethacin group were offered reexcision and one accepted and made a good recovery. There was no difference in pain relief between the groups and no correlation between the degree of HO and level of postoperative pain.

CONCLUSIONS

This study does not support the use of prophylactic indomethacin in severe cerebral palsy patients undergoing PFR. We also question the importance of HO in the outcome of this procedure.

LEVEL OF EVIDENCE

Level III.

Nonsteroidal Anti-inflammatory Drugs as Prophylaxis for Heterotopic Ossification after Total Hip Arthroplasty: A Systematic Review and Meta-Analysis

Heterotopic ossification (HO) is a frequent complication after total hip arthroplasty (THA). Nonsteroidal anti-inflammatory drugs (NSAIDs) have been used as routine prophylaxis for HO after THA. However, the efficacy of NSAIDs on HO, particularly selective NSAIDs versus nonselective NSAIDs, is uncertain.We searched PubMed, Embase, the Cochrane Central Register of Controlled Trials, and clinicaltrials.gov to identify randomized controlled trials with respect to HO after THA. Two reviewers extracted the data and estimated the risk of bias. For the ordered data, we followed the Bayesian framework to calculate the odds ratio (OR) with a 95% credible interval (CrI). For the dichotomous data, the OR and 95% confidence interval (CI) were calculated using Stata version 12.0. The subgroup analyses and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach were used.A total of 1856 articles were identified, and 21 studies (5995 patients) were included. In the NSAIDs versus placebo analysis, NSAIDs could decrease the incidence of HO, according to the Brooker scale (OR = 2.786, 95% CrI 1.879-3.993) and Delee scale (OR = 9.987, 95% CrI 5.592-16.17). In the selective NSAIDs versus nonselective NSAIDs analysis, there was no significant difference (OR = 0.7989, 95% CrI 0.5506-1.125) in the prevention of HO. NSAIDs could increase discontinuation caused by gastrointestinal side effects (DGSE) (OR = 1.28, 95% CI 1.00-1.63, P = 0.046) more than a placebo. Selective NSAIDs could decrease DGSE (OR = 0.48, 95% CI 0.24-0.97, P = 0.042) compared with the nonselective NSAIDs. There was no significant difference with respect to discontinuation caused by non-gastrointestinal side effects (DNGSE) in NSAIDs versus a placebo (OR = 1.16, 95% CI 0.88-1.53, P = 0.297) and in selective NSAIDs versus nonselective NSAIDs (OR = 0.83, 95% CI 0.50-1.37, P = 0.462).NSAIDs might reduce the incidence of HO and increase DGSE in the short-term.

Diffuse idiopathic skeletal hyperostosis: clinical features and pathogenic mechanisms

Diffuse idiopathic skeletal hyperostosis (DISH) is a systemic condition characterized by the ossification and calcification of ligaments and entheses. DISH is observed on all continents and in all races, but most commonly in men over 50 years of age. Although DISH is asymptomatic in most individuals, the condition is often an indicator of underlying metabolic disease, and the presence of spinal or extraspinal ossifications can sometimes lead to symptoms including pain, stiffness, a reduced range of articular motion, and dysphagia, as well as increasing the risk of unstable spinal fractures. The aetiology of DISH is poorly understood, and the roles of the many factors that might be involved in the development of excess bone are not well delineated. The study of pathophysiological aspects of DISH is made difficult by the formal diagnosis requiring the presence of multiple contiguous fully formed bridging ossifications, which probably represent advanced stages of DISH. In this Review, the reader is provided with an up-to-date discussion of the epidemiological, aetiological and clinical aspects of DISH. Existing classification criteria (which, in the absence of diagnostic criteria, are used to establish a diagnosis of DISH) are also considered, together with the need for modified criteria that enable timely identification of early phases in the development of DISH.

Heterotopic ossification after the use of commercially available recombinant human bone morphogenetic proteins in four patients

Heterotopic ossification occurring after the use of commercially available bone morphogenetic proteins has not been widely reported. We describe four cases of heterotopic ossification in patients treated with either recombinant bone morphogenetic protein 2 or recombinant bone morphogenetic protein 7. We found that while some patients were asymptomatic, heterotopic ossification which had occurred around a joint often required operative excision with good results.

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.

No migration of acetabular cups after prophylaxis for heterotopic ossification

The possibility of migration of cementless cups in total joints after prophylaxis of heterotopic ossification with irradiation or nonsteroidal antiinflammatory drugs is a concern. Data investigating component stability with digital methods are lacking. This prospective study analyzed the migration of cementless cups after indomethacin and irradiation prophylaxis with the digital Einzel-Bild-Röntgen-Analyse tool. The irradiation group (106 hips) and the indomethacin group (98 hips) were compared with 82 hips that did not receive any prophylaxis. The same cementless acetabular implants were used in all cases, and patients were observed clinically and radiographically at 2 and 5 years. At the 5-year followup, the number of cups that showed migration greater than 1 mm in the irradiation group (five), the indomethacin group (three), and the control group (four) were not different. No cup was considered loose on the radiographs and no patient underwent revision surgery. The results of our study indicate irradiation or short-course use of indomethacin for prophylaxis of heterotopic ossification did not negatively affect the stability of cementless cups in primary total hip arthroplasties.

Celecoxib versus ibuprofen in the prevention of heterotopic ossification following total hip replacement: a prospective randomised trial

We examined whether a selective cyclooxygenase-2 (COX-2) inhibitor (celecoxib) was as effective as a non-selective inhibitor (ibuprofen) for the prevention of heterotopic ossification following total hip replacement. A total of 250 patients were randomised to receive celecoxib (200 mg b/d) or ibuprofen (400 mg t.d.s) for ten days after surgery. Anteroposterior radiographs of the pelvis were examined for heterotopic ossification three months after surgery. Of the 250 patients, 240 were available for assessment. Heterotopic ossification was more common in the ibuprofen group (none 40.7% (50), Brooker class I 46.3% (57), classes II and III 13.0% (16)) than in the celecoxib group (none 59.0% (69), Brooker class I 35.9% (42), classes II and III 5.1% (6), p=0.002). Celecoxib was more effective than ibuprofen in preventing heterotopic bone formation after total hip replacement.

Heterotopic ossification causing proximal radioulnar synostosis after insertion of a radial head prosthesis

A rare case of radioulnar synostosis following placement of a metal radial head replacement is described and a review of treatment options for heterotopic ossification in the vicinity of the elbow is presented.

Successful excision of neurogenic heterotopic ossification around the hip in cerebral palsy

We present the case of an 11-year-old girl with cerebral palsy, who developed bilateral spontaneous ankylosis of the hips as a result of heterotopic ossification following hip surgery. This was treated successfully by a combination of surgical excision, single dose radiotherapy and bisphosphonate treatment at five months from the time of the original surgery. A review of the literature shows that a combination treatment can be recommended in severe cases of heterotopic ossification to prevent recurrence. A review of neurogenic heterotopic ossification is presented. (Hip International 2005; 15: 123-7) KEY WORDS: Neurogenic heterotopic ossification, Hip reconstruction, Ankylosis, Cerebral palsy.

Severe myositis ossificans in a paraplegic trauma patient: Influence in pressure sore management

Myositis ossificans (MO) is a benign, progressive, ossifying lesion that displays a characteristic zonal histological appearance. MO traumatica is a localized form of heterotopic bone formation, associated with repetitive micro- and/or macrotrauma in the majority of cases. The importance of imaging to differentiate MO from sarcomatous change and to determine maturity of the lesion is identified because suboptimal operative intervention on immature MO inevitably results in recurrence. A severe case of MO in a 24-year-old paraplegic man with chronic bilateral greater trochanteric pressure sores is presented, and the importance of the MO in the etiology and treatment of this case is discussed. An extensive review of the literature is included and integrated.

Incidence of heterotopic ossification following total hip arthroplasty in patients with prior stroke

This study reviewed the incidence of heterotopic ossification and the functional limitations in a cohort of consecutive patients with prior stroke who underwent primary total hip arthroplasty (THA). Thirty-one primary THAs were performed in 22 patients who had a cerebrovascular accident prior to THA. Mean follow-up 35 months. The overall incidence of heterotopic ossification was 36%, with significant Brooker class III and IV heterotopic ossification reported in 22% of patients. The data suggest that prior cerebrovascular accident may pose an increased risk of significant heterotopic ossification following primary THA. Consideration of prophylaxis in this subset of patients may be warranted.

Incidence of heterotopic bone formation after major hip surgery

BACKGROUND

Heterotopic bone formation is a well-established complication of major hip surgery, but traditional reviews of the published literature may have underestimated its frequency.

METHODS

A systematic overview of all the relevant studies was performed to determine reliably the incidence of any heterotopic bone formation and the incidence of each Brooker equivalent grade. Separate estimates were made for patients with total hip replacement and patients with acetabular fracture repair.

RESULTS

A computer-based search identified 218 studies with data on the incidence of heterotopic bone formation after either hip replacement or acetabular fracture repair. These studies included data from an estimated 59 121 operated hips among patients that received total hip replacement and an estimated 998 hips among patients that underwent acetabular fracture repair. In these studies, the incidence of any heterotopic bone formation was 43% after total hip replacement and 51% after acetabular fracture repair. The incidence of severe heterotopic bone formation was 9% and 19%, respectively.

CONCLUSIONS

These results suggest that heterotopic bone formation occurs more frequently after total hip replacement than is generally believed. It is possible that heterotopic bone formation is a more important cause of postoperative disability than has previously been recognized and that effective prophylactic regimens might improve outcome in substantial numbers of patients.

Indomethacin versus radiation therapy for heterotopic ossification after hip arthroplasty

This study compared the efficacy and cost of radiation therapy with indomethacin in the prophylaxis of heterotopic ossification following total hip replacement. Twenty-two patients received a radiation dose of 10 Gy in five fractions, 28 patients 8 Gy in one fraction, and 27 patients 25 mg oral indomethacin three times a day for either 7 or 21 days. Patients at higher risk for heterotopic ossification were more likely to receive radiation therapy than indomethacin. At a mean follow-up of 2 years, there were no differences in failure rates between the high-risk patients treated with radiation and the low-risk patients treated with indomethacin. Currently, the patient-billed cost of radiation is $1400 whereas the cost for indomethacin is approximately $100. Indomethacin appears to be as effective as radiation therapy in patients at low to moderate risk for heterotopic ossification and offers significant cost savings.

Operative treatment of heterotopic hip ossification in patients with coma after brain injury

In 13 joints of 12 patients who sustained traumatic brain injury, heterotopic ossifications of the hip were surgically excised at an average of 15 months after the patients' recovery from coma. All of the patients were referred by neurologists of the postcoma unit who deemed surgery necessary to speed up the rehabilitation program of the patients. Before surgery, three patients were able to ambulate, whereas nine were not ambulatory. Eight hips were ankylosed, whereas five had a severe painful limitation of joint motion. All of the patients were checked at regular intervals after the operation, and the final followup averaged 38 months. In an attempt to prevent postoperative recurrence of ossification, 100 mg of indomethacin was administered daily after surgery for 6 weeks. At followup, 10 patients could ambulate, and two were able to sit in a wheelchair. Patients with poor neuromuscular control tended to lose part of their postoperative range of motion, and heterotopic periarticular ossification recurred in two of them (three hips). No correlation was found between recurrence and the time that elapsed from head injury to the operation, but old ossifications continued to show osteogenic activity at the histologic level.