Prophylaxis of heterotopic ossification of the hip: systematic review and meta-analysis

The immunological contribution to heterotopic ossification disorders

The formation of bone outside the endogenous skeleton is a significant clinical event, rendering affected individuals with immobility and a diminished quality of life. This bone, termed heterotopic ossification (HO), can appear in patients following invasive surgeries and traumatic injuries, as well as progressively manifest in several congenital disorders. A unifying feature of both genetic and nongenetic episodes of HO is immune system involvement at the early stages of disease. Activation of the immune system sets the stage for the downstream anabolic events that eventually result in ectopic bone formation, rendering the immune system a particularly appealing site of early therapeutic intervention for optimal management of disease. In this review, we will discuss the immunological contributions to HO disorders, with specific focus on contributing cell types, signaling pathways, relevant in vivo animal models, and potential therapeutic targets.

External beam radiation therapy for orthopaedic pathology

External beam radiation therapy is essential in the management of a wide spectrum of musculoskeletal conditions, both benign and malignant, including bony and soft-tissue sarcomas, metastatic tumors, pigmented villonodular synovitis, and heterotopic ossification. Radiation therapy, in combination with surgery, helps reduce the functional loss from cancer resections. Although the field of radiation therapy is firmly rooted in physics and radiation biology, its indications and delivery methods are rapidly evolving. External beam radiation therapy mainly comes in the form of four sources of radiotherapy: protons, photons, electrons, and neutrons. Each type of energy has a unique role in treating various pathologies; however, these energy types also have their own distinctive limitations and morbidities.

Long-term results and outcome predictors in one-stage hip reconstruction in children with cerebral palsy

BACKGROUND

One-stage hip reconstruction is the gold standard for treatment of hip displacement in children with cerebral palsy. The aims of this study were (1) to report the subjective clinical, objective clinical, and radiographic outcomes; and (2) to investigate outcome predictors, including the influence of the following risk factors: femoral head shape, migration percentage, direction of migration, and age at surgery.

METHODS

We reviewed 168 hip reconstructions (eighty-two right, eighty-six left) in 121 patients (101 male, twenty female) at a mean follow-up of 7.3 ± 4.6 years (range, four to eighteen years). Surgical outcomes were assessed on the basis of the pain intensity and frequency (measured on 10-point visual analog scales) as well as GMFCS (Gross Motor Function Classification System) and MCPHCS (Melbourne Cerebral Palsy Hip Classification System) scores and postoperative migration percentage. The effects of femoral head shape, preoperative migration percentage, direction of migration, and age at surgery on surgical outcome were assessed by multivariate regression adjusting for potential confounders including sex, triradiate cartilage status, type of cerebral palsy, and surgical technique.

RESULTS

Pain intensity and frequency were reduced significantly. Preoperative femoral head shape had no significant effect on the changes in pain, MCPHCS grade, and GMFCS level. The preoperative migration percentage was the most influential risk factor with respect to postoperative outcome. Age at surgery had no effect on the changes in pain score and GMFCS level. The overall surgical complication rate was 10.5%.

CONCLUSIONS

Our data on 168 hip reconstructions at a mean follow-up of seven years showed significant and clinically meaningful improvements in pain intensity and frequency as well as in clinical scores and hip coverage. Analysis of potential risk factors showed only the preoperative migration percentage to have a relevant influence on outcomes.

Radiation therapy for recurrent heterotopic ossification prophylaxis after partial metatarsal amputation

The formation of heterotopic ossification is a relatively common, yet rarely discussed, cause of re-ulceration after previous partial metatarsal amputation. Excessive bone growth at the amputation site has the potential to create an unwanted prominence on the weightbearing surface of the foot, intuitively increasing plantar pressure and placing the neuropathic patient at greater risk of re-ulceration and limb loss. The aim of the present study was to assess the efficacy of single-dose radiation therapy in preventing recurrent heterotopic ossification. The inclusion criteria consisted of a history of clinically relevant heterotopic ossification formation after partial metatarsal amputation with subsequent partial metatarsal amputation for heterotopic ossification resection, followed by prophylactic single-dose radiation therapy. Eleven consecutive patients meeting the inclusion criteria were identified for the present study. Before the intervention, 10 (91%) patients demonstrated formation of mid- to high-grade heterotopic ossification, and 9 (82%) patients exhibited an associated neuropathic ulceration. On follow-up at least 6 weeks after intervention, 2 (18%) patients exhibited low-grade heterotopic ossification reformation that was not clinically relevant and 9 (82%) did not show signs of heterotopic recurrence. Single-dose radiation therapy can help prevent the formation of heterotopic ossification in high-risk patients, acting as an effective adjunct to surgery in minimizing the risk of re-ulceration and re-amputation in the neuropathic patient.

Risk factors for the development of heterotopic ossification after acetabular fracture fixation

BACKGROUND

Heterotopic ossification (HO) is a common complication of the operative treatment of acetabular fractures. Although the surgical approach has been shown to correlate with the development of ectopic bone, specific risk factors have not been elucidated.

QUESTIONS/PURPOSES

The purposes of this study were to determine specific risk factors associated with the development of severe HO and the frequency with which patients develop severe HO after acetabular fracture fixation through an isolated Kocher-Langenbeck approach.

METHODS

Using an institutional orthopaedic trauma database at a regional Level I trauma center, patients undergoing open treatment of acetabular fractures during the study period (January 2000 to January 2010) were identified. A review of medical records and imaging studies was performed on 508 patients who were treated by the senior author (MR) through an isolated Kocher-Langenbeck approach. During the study period, the senior author used indomethacin for HO prophylaxis in patients who had ipsilateral femur fracture treated with antegrade reamed medullary nailing or severe local soft tissue injury; 49 (10%) of the patients he treated with the Kocher-Langenbeck approach received prophylaxis, and they were excluded from this study, leaving a total of 459 patients who met inclusion criteria. Of those, 147 (29%) were lost to followup or did not have radiographs both before and at a minimum of 6 weeks (median, 1 week; range, 0-3 weeks), leaving 312 (61% of the patients treated with the Kocher-Langenbeck approach during this time) available for this analysis. Demographic data as well as information related to cause of injury, associated periacetabular findings, other system injuries, and treatment were gathered. Final followup radiographs were assessed for the presence of ectopic bone by two of the authors (TJO, AS) using the modified Brooker classification. Logistic regression was performed to identify possible predictors of development of severe ectopic bone.

RESULTS

The only predictor we identified for the development of severe HO was the need for prolonged mechanical ventilation (odds ratio, 7.1; 95% confidence interval, 2.9-17.3; p=0.001). Injury Severity Score, sex, presence of comminution, femoral head impaction, dislocation, degloving injury, debris in the joint, number of other fractures, and head and chest Abbreviated Injury Score>2 did not correlate with severe HO. Severe HO (Brooker Class III or IV) developed in 38 of 312 patients (12%).

CONCLUSIONS

Patients with prolonged mechanical ventilation might benefit from HO prophylaxis given the increased risk of developing severe HO in this patient population. However, future prospective studies need to be performed to verify this finding given the fact that a considerable number of patients were prophylactically treated in this study.

LEVEL OF EVIDENCE

Level IV, prognosticstudy. See Guidelines for Authors for a complete description of levels of evidence.

Radiotherapy for the prophylaxis of heterotopic ossification: a systematic review and meta-analysis of published data

INTRODUCTION

Following surgery, the formation of heterotopic ossification (HTO) can limit mobility and impair quality of life. Radiotherapy has been proven to provide efficacious prophylaxis against HTO, especially in high-risk settings.

PURPOSE

The current review aims to determine the factors influencing HTO formation in patients receiving prophylactic radiotherapy.

METHODS

A systematic search of the literature was conducted on Ovid Medline, Embase and the Cochrane Central Register of Controlled Trials. Studies were included if they reported the percentage of sites developing heterotopic ossification after receiving a specified dose of prophylactic radiotherapy. Weighted linear regression analysis was conducted for continuous or categorical predictors.

RESULTS

Extracted from 61 articles, a total of 5464 treatment sites were included, spanning 85 separate study arms. Most sites were from the hip (97.7%), from United States patients (55.2%), and had radiation prescribed postoperatively (61.6%) at a dose of 700cGy (61.0%). After adjusting for radiation site, there was no statistically significant relationship between the percentage of sites developing HTO and radiation dose (p=0.1) or whether radiation was administered preoperatively or postoperatively (p=0.1). Sites with previous HTO formation were more likely to develop recurrent HTO than those without previous HTO formation (p=0.04). There was a statistically significant negative relationship between the HTO development and the cohort mean year of treatment (p=0.007).

CONCLUSION

Decreases in rates of HTO over time in this patient population may be a function of more efficacious surgical regimens and prophylactic radiotherapy.

Bilateral simultaneous heterotopic ossification of the reflected head of rectus femoris muscle: a case report and review of the literature

Lamellar bone formation in an abnormal location is defined as heterotopic ossification. It commonly occurs around the hip joint and most often involves the abductor muscles. It is a benign condition; however, its etiology remains largely unknown. Most previously reported cases have been due to trauma or intramuscular hemorrhage. In this paper, we present a case of bilateral heterotopic ossification of the reflected head of rectus femoris muscle without antecedent trauma or any other known cause, as the first and unique case in the literature. She was treated by excision of the right symptomatic bony mass via a modified Smith-Petersen approach. Postoperatively, she received 75 mg indomethacin daily for six weeks. She was pain-free and obtained full range of motion 3 weeks after the first intervention.

[Endoprosthetic treatment of osteoporosis-related coxarthrosis : aspects of safe patient treatment]

BACKGROUND

With increasing life expectancy the prevalence of osteoarthritis is also substantially rising. Patients aged between 65 and 75 years scheduled for total joint arthroplasty suffer from undetected osteoporosis in 20-25% of cases.

OBJECTIVES

How to determine osteoporosis during preoperative workup? Which conclusions can be drawn for the operation treatment and the postoperative course?

METHODS

The literature dealing with the prevalence of osteoporosis, perioperative complications of total hip arthroplasty, selected register informations, guidelines for diagnostics and treatment of osteoporosis and for the postoperative treatment are summarized and discussed.

RESULTS

The fracture risk is determined according to the guidelines of the Dachverband Osteologie (DVO, Governing Body on Osteology). The implant and the anchorage are selected based on the risk of suffering from osteoporosis. An intraoperative fracture and early aseptic loosening are the main operative risk factors. For the postoperative course in addition to education about arthroplasty, adequate support for prevention of falls is mandatory. Continuous physiotherapy with muscular strengthening is advisable. The long-term medication should be checked for risks in the PRISCUS list of potentially inappropriate medication in the elderly and non-steroidal anti-inflammatory drugs (NSAIDs) should not be prescribed in patients with cardiac comorbidities. Patients with confirmed osteoporosis should be treated with antiresorptive agents.

Radiotherapy for prevention of heterotopic ossification of the elbow: a systematic review of the literature

BACKGROUND

Heterotopic ossification is a pathological process characterized by abnormal formation of bone in nonskeletal tissue. Radiotherapy for heterotopic ossification of the elbow is questionable because of possible adverse effects.

METHODS

A systematic review of the literature was conducted in MEDLINE, Scopus, ISI Web of Science, National Institute for Health and Clinical Excellence, National Guideline Clearinghouse, System for Information on Grey Literature in Europe, ClinicalTrials.gov, Cochrane Central Register of Clinical Trials, and Cochrane Database of Systematic Reviews up to April 2012. All published articles assessing interventions including radiotherapy for prevention of heterotopic ossification in the elbow of adult patients were considered. Information was recorded by the first two authors, and disagreements in interpretation were resolved by consensus.

RESULTS

In total, 27 studies using radiotherapy for elbow heterotopic ossification were identified (1 randomized clinical trial, 1 case-control study, and 25 case reports and case series) in the literature. Most of them used a single dose of 7.0 Gy. The randomized clinical trial was stopped early because of severe adverse effects (pseudarthrosis) caused by radiation. The case-control study showed that radiotherapy did not effectively prevent recurrence of heterotopic ossification. The case reports and case series mentioned only sparse adverse events.

CONCLUSION

The use of radiation therapy for prevention of heterotopic ossification of the elbow is supported by weak evidence.

Low-dose irradiation and constrained revision for severe, idiopathic, arthrofibrosis following total knee arthroplasty

Treatment options for arthrofibrosis following total knee arthroplasty include manipulation under anesthesia, open or arthroscopic arthrolysis, and revision surgery to correct identifiable problems. We propose preoperative low-dose irradiation and Constrained Condylar or Rotating-hinge revision for severe, idiopathic arthrofibrosis. Irradiation may decrease fibro-osseous proliferation while constrained implants allow femoral shortening and release of contracted collateral ligaments. Fourteen patients underwent fifteen procedures for a mean overall motion of 46° and flexion contracture of 30°. One patient had worsening range of motion while thirteen patients had 57° mean gain in range of motion (range 5°-90°). Flexion contractures decreased by a mean of 28°. There were no significant complications at a mean follow up of 34 months (range 24 to 74 months).

Preoperative irradiation for the prevention of heterotopic ossification induces local inflammation in humans

Radiation of the hip is an established method to prevent heterotopic ossification (HO) following total hip arthroplasty (THA) but the precise mechanism is unclear. As inflammatory processes are suggested to be involved in the pathogenesis of HO, we hypothesized that the preoperative irradiation impacts local immune components. Therefore, we quantified immune cell populations and cytokines in hematomas resulting from the transection of the femur in two groups of patients receiving THA: patients irradiated preoperatively (THA-X-hematoma: THA-X-H group) in the hip region (7 Gy) in order to prevent HO and patients who were not irradiated (THA-H group) but were postoperatively treated with non-steroidal anti-inflammatory drugs (NSAIDs). Radiation resulted in significantly increased frequencies of T cells, cytotoxic T cells, NKT cells and CD25+CD127- Treg cells, whereas the number of naive CD45RA-expressing cytotoxic T cells was reduced. These results indicate differential immune cell activation, corroborated by our findings of significantly higher concentrations of pro-inflammatory cytokines (e.g., IL-6, IFNγ) and chemokines (e.g., MCP-1, RANTES) in the THA-X-H group as compared to THA-H group. In contrast, the concentration of the angiogenic VEGF was significantly suppressed in the THA-X-H group. We conclude that preoperative irradiation results in significant changes in immune cell composition and cytokine secretion in THA-hematomas, establishing a specific - rather proinflammatory - milieu. This increase of inflammatory activity together with the observed suppression in VEGF secretion may contribute to the prevention of HO.

Assessment and management of chronic pain in patients with stable total hip arthroplasty

Total hip arthroplasty (THA) is one of the most successful operations that can restore function and relieve pain. Although a majority of the patients achieve significant pain relief after THA, there are a number of patients that develop chronic pain for unknown reasons. A literature search was performed looking for chronic pain after total hip arthroplasty and stable THA. Major causes of chronic pain include aseptic loosening or infection. However, there is a subset of patients with a stable THA that present with chronic pain which can have several aetiologies. These include soft tissue, bony, neurological, vascular and psychological causes. Essential for successful treatment is the ability to make the correct diagnosis. Thus therapy may be either non-operative or operative. In addition, diagnosis and management often may require multidisciplinary approaches to successfully alleviate chronic pain in these patients with a stable prosthesis.

Does computer-assisted surgery improve postoperative leg alignment and implant positioning following total knee arthroplasty? A meta-analysis of randomized controlled trials?

PURPOSE

Computer-assisted surgery has been proposed as a technique to improve implant alignment during total knee arthroplasty (TKA). However, there is still a debate over the accuracy of placing the femoral and tibial components using computer-assisted systems in TKA. The aim of this study is to establish whether computer-assisted surgery leads to superior mechanical leg axis and implant positioning than conventional technique in patients with primary TKA.

METHODS

Major electronic databases were systematically searched to identify relevant studies without language restriction. A meta-analysis of 41 randomized controlled trials (RCTs) or quasi-RCTs was performed in a random effects model. A subgroup analysis was conducted by type of navigation system to explore the clinical heterogeneity between these trials. The following radiographic parameters were used to compare computer-assisted surgery with conventional technique: (1) mechanical leg axis, (2) femoral component coronal alignment, (3) tibial component coronal alignment, (4) femoral component sagittal alignment, and (5) tibial component sagittal alignment.

RESULTS

For the mechanical leg axis and coronal positioning of femoral and tibial components, there are statistically significant reductions in the number of patients with malalignment in the CAS group if the outlier cutoff value is ±3 or 2° in the coronal and sagittal planes, respectively. Subgroup analysis demonstrates that CT-free navigation systems provide better alignment than conventional techniques in the coronal and sagittal alignment of femoral components within ±3 and 2°. If the outlier cutoff value for the tibial sagittal alignment is ±2°, the outlier percentages are higher in the CT-free navigation group than in the conventional group. However, there was no significant difference in the tibial sagittal alignment at ±3°.

CONCLUSION

Computer-assisted surgery does improve mechanical leg axis and component orientation in TKAs. However, high-quality RCTs are necessary to determine whether surgeons could use computer-assisted techniques to achieve a targeted tibial slope in TKA.

LEVEL OF EVIDENCE

Therapeutic study (Systematic review of Level I/II studies), Level II.

Management of posttraumatic radioulnar synostosis

Posttraumatic radioulnar synostosis is a rare complication following fracture of the forearm and elbow. Risk factors for synostosis are related to the initial injury and surgical management of the fracture. Typically, patients present with complete loss of active and passive forearm pronation and supination. Evidence of bridging heterotopic bone between the radius and ulna can be seen on plain radiographs. Although nonsurgical management is sufficient in some cases, surgical excision is typically required. The timing of surgical intervention remains controversial. However, early resection between 6 and 12 months after the initial injury can be performed safely in patients with radiographic evidence of bony maturation. Surgical management consists of complete resection of the synostosis with optional interposition of biologic or synthetic materials to restore forearm rotation. A low recurrence rate can be achieved following primary radioulnar synostosis excision without the need for routine adjuvant prophylaxis.

Incidence and risk factors of heterotopic ossification following major elbow trauma

Heterotopic ossification is a common complication of Orthopaedic Trauma Association (OTA) type C distal humerus fractures and ulnohumeral fracture dislocations. The purpose of this study was to precisely define the incidence of heterotopic ossification following major elbow trauma and to identify risk factors for the development of clinically significant heterotopic ossification and for surgical excision of elbow heterotopic ossification.Current Procedural Terminology codes identified 156 patients who underwent operative intervention for a distal humerus fracture or an ulnohumeral fracture dislocation at 2 Level I trauma centers over 6 years. The incidence of elbow heterotopic ossification was recorded at >90 days following the definitive procedure. Risk factors for the development of class 3 or 4 heterotopic ossification and for surgical excision of heterotopic ossification were evaluated using separate multivariable logistic regression analyses. Brooker class 3 or 4 heterotopic ossification occurred following 18 (14%) of 125 distal humerus fractures, 15 (22%) of 69 OTA type C distal humerus fractures, and 11 (35%) of 31 ulnohumeral fracture dislocations. Surgical excision of heterotopic ossification was performed after 12 (10%) of 125 distal humerus fractures, 10 (14%) of 69 OTA type C distal humerus fractures, and 8 (26%) of 31 ulnohumeral fracture dislocations. Sustaining a severe elbow injury (P<.05) or a delay of fixation (P=.05) was found to be independent risk factors for Brooker class 3 or 4 heterotopic ossification. Severe elbow injury (P<.05) and male sex (P<.05) were associated with operative excision of heterotopic ossification.

Physical therapy and surgery

Physical therapy and orthopedic surgery are important components in the treatment of ankylosing spondylitis (AS). Supervised physical therapy is more effective than individual or unsupervised exercise in improving symptoms, but controlled trials suggest that combined inpatient and outpatient therapy provides the greatest improvement. Recommendations for exercise are universal, but the best types and sequence of therapies are not known. Total hip replacement is the surgery most commonly performed for AS, with good long-term implant survival. Heterotopic ossification may occur no more frequently after hip replacement in patients with AS than in patients with other diseases. Corrective spinal surgery is rarely performed and requires specialized centers and experienced surgeons.

Periarticular infiltration in total hip replacement: effect on heterotopic ossification, analgesic requirements and outcome

BACKGROUND

Up to 80% of patients develop heterotopic ossification (HO) following total hip replacement (THR) and high grades may adversely affect outcome. This study investigated the influence of local infiltration of a NSAID (Ketorolac) and local anaesthetic on the incidence and grade of HO following THR, the effect on post-operative opiate analgesic requirement and on patient reported outcome score.

METHODS

A retrospective study was performed on 118 THRs performed without periarticular infiltration from 2003 to 2005, and on 211 performed with infiltration from 2005 to 2008. Pre-operative and 12-month radiographs were examined and HO graded according to the Brooker classification. Peri-operative analgesic requirements and NSAID use were noted and outcome was measured at 1 year with the Oxford Hip Score.

RESULTS

Univariate and multivariate analysis indicated that single-dose periarticular NSAID infiltration did not reduce the incidence or grade of HO. Preoperative HO (p = 0.005) and enthesopathy (p = 0.027) were significant predictors of post-operative HO. The use of post-operative oral NSAID (except aspirin) significantly reduced HO (p = 0.001). Periarticular infiltration significantly reduced opiate analgesia use in the first 24 h (p < 0.001) and length of inpatient stay (p < 0.001). There was no difference in Oxford Hip Score at 1 year.

CONCLUSION

Preoperative enthesopathies are a risk factor for postoperative HO. Periarticular infiltration of NSAID and local anaesthetic does not reduce HO incidence or grade in THR, but does reduce perioperative opiate requirements and length of hospital stay.

The incidence of heterotopic ossification after hip arthroscopy

BACKGROUND

Minimally invasive techniques to treat femoroacetabular impingement (FAI), snapping hip syndrome, and peritrochanteric space disorder (PSD) were developed to reduce complications and recovery time. Although a multitude of studies have reported on the incidence of heterotopic ossification (HO) after open procedures of the hip, there is little known about the rate of HO after hip arthroscopy.

HYPOTHESES

The incidence of HO after hip arthroscopy is comparable with that after open surgical dislocation of the hip and can be reduced with the addition of indomethacin to an existing nonsteroidal anti-inflammatory medication prophylaxis protocol.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Between July 2008 and July 2010, 616 primary hip arthroscopies were performed to treat FAI and PSD. In July 2009, indomethacin was added in the acute postoperative period to an existing HO prophylactic protocol of naproxen administered for 30 days postoperatively. Postoperative radiographs were reviewed to detect the presence and classify the size and location of HO. Odds ratios and logistic regression explored predictor variables and their relationships with HO, with P < .05 defined as significant.

RESULTS

Twenty-nine (21 male, 8 female) of 616 (4.7%) hip procedures developed HO postoperatively. Brooker classification of HO was 18 grade I, 4 grade II, 6 grade III, and 1 grade IV. Mean follow-up was 13.2 months (range, 2.9-26.5 months). Rate of HO for cases with and without indomethacin for prophylaxis was 1.8% (6/339) and 8.3% (23/277), respectively. This difference was statistically significant (P < .05), and patients who underwent protocol 1 were 4.36 times more likely to develop HO postoperatively than those who had protocol 2. The majority of cases of HO (72.4%) occurred in male patients, and all cases occurred in the setting of osteoplasty performed for symptomatic FAI. We were not able to demonstrate statistically significant clinical risk factors that were predictive for the development of postoperative HO. However, the data clearly demonstrate that the performance of arthroscopic osteoplasty with a capsular cut in male patients represented the majority of cases, who are likely the group at highest risk. Seven cases (~1%) required revision procedures to excise HO. There were no cases of recurrence of HO after excision, whether it was performed open or arthroscopically.

CONCLUSION

The addition of indomethacin is effective in reducing the incidence of HO after hip arthroscopy and should be especially considered in male patients who undergo osteoplasty for correction of symptomatic FAI.

[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.

Human early fracture hematoma is characterized by inflammation and hypoxia

BACKGROUND

An effective immune system, especially during the inflammatory phase, putatively influences the quality and likelihood of bone healing. If and how this is reflected within the initial fracture hematoma is unclear.

QUESTIONS/PURPOSES

We therefore asked the following questions: (1) Does the local expression in fracture hematoma of genes involved in adaptation to hypoxia, migration, angiogenesis, and osteogenesis vary as compared to the peripheral blood? (2) Do these changes occur time dependently? (3) Is the gene expression during fracture hematoma formation altered by irradiation?

METHODS

Cells from fracture hematoma of 20 patients and hematomas formed in 40 patients after THA (20 without and 20 with preoperative radiation) were isolated and RNA was extracted to analyze the influence of oxygen deprivation during fracture healing on mRNA expression of genes (HIF1A, LDHA, and PGK1) involved in immunoregulation (IL6, IL8, CXCR4), angiogenesis (VEGF, IL8), and osteogenesis (SPP1, RUNX2) by quantitative PCR.

RESULTS

We observed locally increased LDHA gene expression in fracture hematoma cells (6-72 h post fracture) reflecting the adaptation to hypoxia. IL6, IL8, and VEGF upregulation indicated hypoxia-mediated inflammation and angiogenesis; increased CXCR4 expression reflected immigration of immune cells. Osteogenic differentiation was reflected in the increased expression of the SPP1 and RUNX2 genes. The increased expression of the LDHA, VEGF, IL8, SPP1 and RUNX2 genes occurred time dependently. Irradiation suppressed HIF1A, IL6, IL8, CXCR4, and RUNX2 gene expression.

CONCLUSIONS

Our data suggest cells in the fracture hematoma (1) adapt to hypoxia and (2) promote inflammation in fracture healing at the mRNA level, indicating early involvement of the immune system.

CLINICAL RELEVANCE

The initial fracture hematoma is important for the onset of angiogenesis, chemotaxis, and osteogenesis.

Rationale for and methods of superiority, noninferiority, or equivalence designs in orthopaedic, controlled trials

BACKGROUND

To provide value-based healthcare in orthopaedics, controlled trials are needed to assess the comparative effectiveness of treatments. Typically comparative trials are based on superiority testing using statistical tests that produce a p value. However, as orthopaedic treatments continue to improve, superiority becomes more difficult to show and, perhaps, less important as margins of improvement shrink to clinically irrelevant levels. Alternative methods to compare groups in controlled trials are noninferiority and equivalence. It is important to equip the reader of the orthopaedic literature with the knowledge to understand and critically evaluate the methods and findings of trials attempting to establish superiority, noninferiority, and equivalence.

QUESTIONS/PURPOSES

I will discuss supplemental and alternative methods to superiority for assessment of the outcome of controlled trials in the context of diminishing returns on new therapies over old ones.

METHODS

The three methods-superiority, noninferiority, and equivalence-are presented and compared, with a discussion of implied pitfalls and problems.

RESULTS

Noninferiority and equivalence offer alternatives to superiority testing and allow one to judge whether a new treatment is no worse (within a margin) or substantively the same as an active control. Noninferiority testing also allows for inclusion of superiority testing in the same study without the need for adjustment of the statistical methods.

CONCLUSIONS

Noninferiority and equivalence testing might prove most valuable in orthopaedic, controlled trials as they allow for comparative assessment of treatments with similar primary end points but potentially important differences in secondary outcomes, safety profiles, and cost-effectiveness.

Economic evaluation of NSAID and radiation to prevent heterotopic ossification after hip surgery

INTRODUCTION

Heterotopic ossification (HO) is a known complication in hip surgery, but there is still uncertainty whether to use non-steroidal anti-inflammatory drugs (NSAID) or radiation in its prevention. While the literature focuses almost exclusively on (as it turns out the lacking) difference in effectiveness, one important difference that has been widely unacknowledged thus far is cost-effectiveness.

METHOD

We systematically reviewed the literature to extract evidence-based estimates of treatment effectiveness, complications, and associated costs. These variables are combined in a decision tree to calculate costs for all potential outcomes and tested in sensitivity analyses. Finally, the incremental cost-effectiveness ratio (ICER) was calculated. Data on the effectiveness of both treatments could be extracted from nine randomized controlled trails and one meta-analysis.

RESULTS

Across the 95% confidence interval for the risk difference of HO despite treatment radiation is either dominated by NSAID, which are cheaper and more effective, or has an ICER of US$ 5,858.93 per additionally prevented case of HO.

CONCLUSION

Among the studied variables that might affect cost-effectiveness, the rate of complications requiring treatment was by far the most influential.

Harnessing and modulating inflammation in strategies for bone regeneration

Inflammation is an immediate response that plays a critical role in healing after fracture or injury to bone. However, in certain clinical contexts, such as in inflammatory diseases or in response to the implantation of a biomedical device, the inflammatory response may become chronic and result in destructive catabolic effects on the bone tissue. Since our previous review 3 years ago, which identified inflammatory signals critical for bone regeneration and described the inhibitory effects of anti-inflammatory agents on bone healing, a multitude of studies have been published exploring various aspects of this emerging field. In this review, we distinguish between regenerative and damaging inflammatory processes in bone, update our discussion of the effects of anti-inflammatory agents on bone healing, summarize recent in vitro and in vivo studies demonstrating how inflammation can be modulated to stimulate bone regeneration, and identify key future directions in the field.

Management of Pelvic Heterotopic Ossification Post-Myocutaneous Flap Reconstruction of a Sacral Pressure Ulcer

Heterotopic ossification (HO) is a process whereby lamellar bone forms in the soft tissues surrounding a joint. The most common type of HO is traumatic myositis ossificans, which develops following traumatic injuries, burns or arthroplasty. A variety of other forms of HO also exist, such as those associated with central nervous system injury and systemic forms that can manifest at other joints simultaneously. Clinically, patients can present with decreased range of motion, pressure ulcers, nerve compression, swelling, pain or asymptomatically. Symptomatic patients are most commonly treated with surgical debridement of the affected heterotopic deposits.

Spinal dysraphism (SD) is a term describing a wide range of congenital malformations of the neural tube, ranging from spina bifida occulta to the more severe form, myelomeningocele. The cause of SD is multifactorial and has been associated with chromosomal disorders, teratogenic exposure and folate deficiency. Many patients with SD experience neuropathy below the affected neurological level, making them particularly susceptible to pressure ulcers. If these ulcers are severe and do not respond to conservative therapy, they often require surgical debridement and flap reconstruction – a clinical scenario that rarely results in HO.

The present article describes a case involving a patient with pelvic HO following myocutaneous flap reconstruction of a pressure ulcer. The patient was successfully treated with oral bisphosphonate and aggressive physiotherapy.

Heterotopic ossification after primary total ankle arthroplasty

BACKGROUND

Heterotopic ossification following lower-limb joint arthroplasty is a challenging clinical problem. No comprehensive study has been conducted on heterotopic ossification after total ankle arthroplasty, to our knowledge. The purpose of this study was to evaluate the prevalence and location of heterotopic ossification after primary total ankle arthroplasty, predisposing factors, and effects on clinical outcomes, and to develop a method of classification.

METHODS

Eighty ankles in eighty patients with a primary total ankle arthroplasty were followed for a mean (and standard deviation) of 31.9 ± 11.3 months (range, twenty-four to sixty-five months). The prevalence and location of heterotopic ossification, predisposing factors, and outcomes were analyzed, and a method of classification was developed.

RESULTS

Twenty (25%) of the eighty ankles demonstrated postoperative heterotopic ossification, with the majority of the cases in the posterior aspect of the ankle. The heterotopic ossification was Class I in four cases (20%); Class II, in five (25%); Class III, in four (20%); and Class IV, in seven (35%). Symptomatic heterotopic ossification was reported in eight patients (10%), and two required surgical resection because of intractable pain. Ankles that developed heterotopic ossification had significantly longer operative times, less postoperative motion, and lower American Orthopaedic Foot & Ankle Society ankle-hindfoot scores at the six, twelve, and twenty-four-month follow-up examinations (p < 0.05 for all).

CONCLUSIONS

This study demonstrates that the prevalence of heterotopic ossification following primary total ankle arthroplasty is considerable, and that heterotopic ossification is associated with reduced ankle motion and a poor clinical outcome at a mean of two years postoperatively. Care is needed to attempt to reduce the occurrence of heterotopic ossification.

Complications after metal-on-metal hip resurfacing arthroplasty

This article determines the incidence and cause of the complications commonly associated with metal-on-metal hip resurfacing implants and the proposed methods to prevent these complications. The literature available in PubMed was reviewed. Complication rates after hip resurfacing are low, and the procedure has shown both safety and efficacy in the hands of surgeons trained in specialized centers. Proper surgical technique can further reduce the incidence of femoral neck fracture, component loosening, and abnormal wear of the prosthesis. A more systematic detection of adverse local tissue reactions is needed to provide accurate assessments of their prevalence.

Postoperative radiation therapy after hip replacement in high-risk patients for development of heterotopic bone formation

PURPOSE

To report the results of postoperative radiation therapy in preventing the development of heterotopic bone formation after hip replacement surgery in high-risk patients.

PATIENTS AND METHODS

Between 1991 and 2007, 44 patients were preventively treated with postoperative RT after total hip replacement. In total, 47 hips were treated. All patients were considered at high risk for developing heterotopic bone formation. Most patients (63.5%) were treated because of a history of severe osteoarthritis or ankylosing spondylitis. All patients were treated with shaped parallel-opposed fields with a single fraction of 7 Gy using 6 or 18 MV photons. Most patients (94%) received radiation therapy within 72 hours postoperative and in only three patients radiation therapy was delivered after 72 hours post-surgery (5-8 days).

RESULTS

Minimum follow-up was 1 year. There were 18 females and 26 males. Median age was 63 years (range: 18-80). Treatments were well tolerated and no acute toxicity was seen post-radiation therapy. Only one of the 47 hips (2%) developed heterotopic bone formation. This patient received postoperative radiation therapy to both hips but only developed heterotopic bone formation in one of them. None of the three patients treated beyond 72 hours failed. To date no late toxicity has been observed.

CONCLUSION

The use of postoperative radiation therapy was an effective and safe treatment in the prevention of heterotopic bone formation in a high-risk group of patients undergoing total hip replacement.

Management of pelvic heterotopic ossification post-myocutaneous flap reconstruction of a sacral pressure ulcer

Heterotopic ossification (HO) is a process whereby lamellar bone forms in the soft tissues surrounding a joint. The most common type of HO is traumatic myositis ossificans, which develops following traumatic injuries, burns or arthroplasty. A variety of other forms of HO also exist, such as those associated with central nervous system injury and systemic forms that can manifest at other joints simultaneously. Clinically, patients can present with decreased range of motion, pressure ulcers, nerve compression, swelling, pain or asymptomatically. Symptomatic patients are most commonly treated with surgical debridement of the affected heterotopic deposits.Spinal dysraphism (SD) is a term describing a wide range of congenital malformations of the neural tube, ranging from spina bifida occulta to the more severe form, myelomeningocele. The cause of SD is multifactorial and has been associated with chromosomal disorders, teratogenic exposure and folate deficiency. Many patients with SD experience neuropathy below the affected neurological level, making them particularly susceptible to pressure ulcers. If these ulcers are severe and do not respond to conservative therapy, they often require surgical debridement and flap reconstruction - a clinical scenario that rarely results in HO.The present article describes a case involving a patient with pelvic HO following myocutaneous flap reconstruction of a pressure ulcer. The patient was successfully treated with oral bisphosphonate and aggressive physiotherapy.

Does minimally invasive surgery improve short-term recovery in total knee arthroplasty?

BACKGROUND

Concerns have been raised regarding minimally invasive surgery (MIS) and its possible effect on postoperative functional recovery, complications, and survival rate after TKA.

QUESTIONS/PURPOSES

We specifically asked whether MIS TKA would be associated with (1) increased operative time, (2) reduced blood loss, (3) shortened hospital stay, (4) faster recovery of ROM, (5) higher knee scores, (6) inferior component positioning, and (7) increased complications.

METHODS

We performed a systematic literature search of randomized controlled trials between minimally invasive and standard approaches in TKA that compared operative time, blood loss, ROM, knee scores, component positioning, and complications. We conducted a systematic review and meta-analysis of 13 trials published from 2007 to 2009 of MIS versus standard TKA.

RESULTS

Patients in the MIS group had longer operating times (10-19 minutes). Mean Knee Society scores were better after MIS than after the standard procedure at 6 and 12 weeks postoperatively, but not after 6 months. Improvement in ROM occurred more rapidly in the MIS group 6 days after TKA but later improvements are not clearly documented. We identified no differences between minimally invasive and standard approaches regarding the short-term overall complications and alignment of femoral and tibial components. However, wound healing problems and infections occurred more frequently in the MIS group.

CONCLUSIONS

MIS leads to faster recovery than conventional surgery with similar rates of component malalignment but is associated with more frequent delayed wound healing and infections. Potential benefits in long-term survival rate and functional improvement require additional investigation. Level of Evidence Level II, therapeutic study (systematic review). See the Guidelines for Authors for a complete description of levels of evidence.