Heterotopic bone formation after total hip arthroplasty in patients with primary or secondary coxarthrosis

Total Hip Arthroplasty for Patients Who Have Ankylosing Spondylitis: Is Postoperative Irradiation Required for Prophylaxis of Heterotopic Ossification?

Postoperative radiation for prevention of heterotopic ossification (HO) has been proven effective for the patients with ankylosing spondylitis (AS) after total hip arthroplasties (THA). This study aims to evaluate the effect of postoperative radiation in HO formation following THA in patients with AS. We retrospectively reviewed 129 hips from 91 patients with AS receiving primary THA from July 2004 to December 2012. There were total 38 patients (53 hips) did not receive postoperative prophylaxis in Group I. Moreover, 53 patients (76 hips) received postoperative single-fraction radiotherapy of 500 cGy in Group II. After a minimum 12-month follow-up, there was no significant difference in HO formation between the two groups (P=0.210). This study suggests that postoperative radiation may not be necessary in Asian patients.

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.

Aspirin decreases the prevalence and severity of heterotopic ossification after 1-stage bilateral total hip arthroplasty for osteoarthrosis

Heterotopic ossification (HO) is a frequent complication after total hip arthroplasty (THA). We retrospectively evaluated the prevalence and severity of HO in patients with osteoarthrosis who underwent 1-stage bilateral THA (OSBTHA) and compared those who received aspirin with those who received Coumadin for postoperative chemothromboprophylaxis. The aspirin group consisted of 66 patients (132 hips), with a mean age of 64 years (SD, 8.5). The Coumadin group consisted of 67 patients (134 hips), with a mean age of 60 years (SD, 10.2). Overall, HO was detected in 124 hips (46.6%). There were 43 hips (32.5%) with HO in the aspirin group and 81 (60.4%) in the Coumadin group (P < .00005). Aspirin significantly decreases the prevalence and severity of HO in comparison to Coumadin after OSBTHA.

The origin of osteoprogenitor cells responsible for heterotopic ossification following hip surgery: an animal model in the rabbit

PURPOSE

To investigate the source of osteoprogenitor cells responsible for heterotopic ossification (HO) following total hip arthroplasty in an animal model.

METHODS

New Zealand White (NZW) rabbits (n = 20) received a radiation treatment 24 h preoperatively to the hip joint of one hindquarter and to the femoral shaft of the contralateral side. Subjects underwent bilateral hip surgery 24 h after treatment. Subjects were euthanized and radiographed 4 months postoperatively. Heterotopic ossification was graded according to a modified Brooker scale. Mean grade, intra-observer reliability, and statistical significance (p < 0.05) were evaluated to compare the severity of heterotopic ossification between hindquarters treated with hip irradiation versus those treated with femoral shaft irradiation.

RESULTS

The Fleiss Weighted Kappa Statistic indicated "almost perfect" (0.872) intra-rater reliability of radiographic heterotopic ossification grading. The average heterotopic ossification grade for the group receiving radiation to the hip was significantly greater than that for the group receiving radiation to the femoral shaft (2.575 versus 2.0, p < 0.02).

CONCLUSION

Although both have some beneficial effect, our results demonstrate that irradiation of the femoral canal is significantly more effective than irradiation of the hip joint and abductor musculature for heterotopic ossification prophylaxis. This suggests that osteoprogenitor cells responsible for heterotopic ossification originate from both the hip abductors and the femoral canal, but the data provide indirect evidence that the femoral canal may be a more dominant source of these cells in the rabbit model.

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.

The efficacy of 500 CentiGray radiation in the prevention of heterotopic ossification after total hip arthroplasty: a prospective, randomized, pilot study

A prospective, randomized, pilot study comparing 500 cGy (group A) versus 1,000 cGy (group B) radiation treatment for the prevention of heterotopic bone in a consecutive group of high-risk patients undergoing total hip arthroplasty was performed. Treatment was initiated within ninety-six hours and given in equal, divided doses: 2 doses for group A and 5 doses for group B. No statistically significant difference was found in the demographics between the 2 groups. At follow-up evaluation, the distribution of heterotopic bone according to the Brooker classification was: group A, 9 class 0, 17 class 1, one class 2, and 2 class 3. Group B: 17 class 0, 10 class 1, 2 class 2, and one class 3. This difference was not statistically significant (P=.086). Only 3 cases were considered treatment failures, for a success rate of 93% in group A and 97% in group B. As a result of this pilot study, 500 cGy radiation treatment appears to be effective in the prevention of clinically significant heterotopic ossification after total hip arthroplasty.

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.

Naproxen in the prevention of heterotopic ossification after total hip replacement

The effectiveness of naproxen, indomethacin, and a placebo were compared for the prevention of heterotopic ossification after total hip arthroplasty. Eighty-four men at high risk of experiencing heterotopic ossification received randomly either naproxen 750 mg per day, indomethacin 75 mg per day, or a placebo for 6 consecutive weeks after surgery. Efficacy analysis showed that in 70% of patients treated with naproxen, in 34.8% of those treated with indomethacin, and in 15% of those treated with a placebo, no heterotopic ossification appeared on radiographs taken at 6 months. Naproxen was significantly more effective than the placebo or indomethacin in preventing the development of heterotopic ossification. Stratification into five categories, according to Brooker's classification at 6 months, showed that both drugs were equally superior to the placebo. Class III heterotopic ossification occurred only in patients who were given the placebo. The improvement in clinical criteria was comparable in the three groups, although at 6 months there was an improvement in abduction in patients treated with indomethacin compared with those treated with naproxen and the placebo. The overall tolerance was rated good by 87% of patients and 86% of physicians, with no difference between the groups. The results show that naproxen, given daily for 6 weeks, is an effective and safe medication for the prevention of heterotopic ossification after total hip replacement.

Radiation therapy for heterotopic ossification

Heterotopic ossification is a common complication after bone and joint surgery. If the disease progresses, it may cause pain and disability, eventually defeating the purpose of surgery in the first place. Today, prophylactic treatment is indicated after surgery. Both nonsteroidal antiinflammatory drugs and radiation therapy are effective. Radiation therapy is associated with fewer side effects and is preferred. Single-dose postoperative irradiation has been found to be as effective as fractionated radiation therapy.

The Frank Stinchfield Award. Inhibition of heterotopic ossification with radiation therapy in an animal model

An animal model for the study of heterotopic ossification was developed and the effects of perioperative radiation were analyzed. In Phase I, New Zealand White rabbits (n = 18) underwent surgery either with or without muscle injury on each hip to establish the most reliable model in which to study heterotopic ossification. In Phase II, rabbits (n = 36) underwent either 400, 800, or 1200 cGy radiation to one hip 24 hours after bilateral hip surgery to establish a dose response relationship for postoperative radiation therapy. In Phase III, rabbits (n = 24) underwent preoperative radiation therapy (800 cGy) at 4, 16, or 24 hours preoperatively to investigate the mechanism of action and efficacy of preoperative radiation therapy. Monthly radiographs were graded by blinded observers for severity of heterotopic ossification. Mean grade, intraobserver and interobserver variability, and statistical significance were evaluated. In Phase II, 17 of 18 rabbits generated heterotopic ossification in both hips, and the mean grade of heterotopic ossification was always greater on the operative side with intentional muscle injury. Variability in the grading was considered excellent. Phase II revealed that 800 cGy was the minimal effective dose. Contrary to hypothesis, Phase III revealed an increasing grade of heterotopic ossification coinciding with a decreasing preoperative time interval, with the difference in heterotopic ossification grade with 24-hour versus 4-hour preoperative radiation being significant. The rabbit model is reliable and reproducible and closely resembles the human clinical situation after hip surgery. Preoperative and postoperative radiation effectively prevented heterotopic ossification formation. The results support the use of preoperative radiation and establish a need for additional investigation regarding the mechanism of action and timing of preoperative radiation therapy.

Heterotopic ossification: a comparison between reamed and unreamed femoral nailing

Heterotopic ossification in the abductor region of the hip following reamed intramedullary femoral nailing has an incidence as high as 68 per cent. A definitive triggering factor for heterotopic ossification remains obscure, but it has been suggested that there may be both local and systemic influences. Previous work has only been able to show a statistical correlation with systemic factors. Sixty antegrade femoral nailings were performed in 58 patients, of which 32 were unreamed. There was no significant difference between the two groups for systemic risk factors known to have statistical correlation with the formation of heterotopic bone. The incidence of heterotopic ossification in the reamed nail group was 35.7 per cent and 9.4 per cent in the unreamed nail group (P = 0.01). The difference in the incidence of heterotopic bone formation seems to be due to local factors, in particular the generation of osteogenic reaming debris, which are important in the pathophysiology of heterotopic ossification seen in femoral intramedullary nailing.

Preoperative irradiation for prevention of heterotopic ossification following total hip arthroplasty

Eighty-six hips in eighty-five patients who were considered to be at risk for heterotopic ossification following a total hip arthroplasty were prospectively randomized or assigned to one of two treatment groups that received a single 800-centigray dose of limited-field radiation either preoperatively (Group I) or postoperatively (Group II). The risk factors for postoperative heterotopic ossification included previous heterotopic ossification following an operation about the hip, hypertrophic osteoarthrosis or post-traumatic osteoarthrosis characterized by the presence of extensive osteophytes, radiographic evidence of diffuse idiopathic skeletal hyperostosis, and ankylosing spondylitis. The hips in Group I were irradiated within 6.1 hours before the operation and those in Group II, within 51.3 hours after the operation. Either extra-field ossification or heterotopic ossification was observed in forty-one (48 per cent) of the eighty-six hips, thereby confirming the high risk for the population in this study. After a minimum duration of follow-up of six months, thirty-seven (76 per cent) of the forty-nine hips that had been treated with preoperative irradiation exhibited no new heterotopic ossification and eleven, progression to grade-I or II ossification. The remaining hip in that group was in a woman who had Paget disease as well as previous grade-IV (ankylosing) heterotopic ossification about the ipsilateral hip; heterotopic ossification progressed from grade II on the radiographs made immediately after the index revision procedure to grade III at the most recent follow-up assessment. Of the thirty-seven hips that had been treated with postoperative irradiation, twenty-seven (73 per cent) exhibited no new heterotopic ossification and nine had progression from grade-0 to grade-I ossification. The remaining hip in that group was in a man who had Parkinson disease and previous grade-III ossification about the ipsilateral hip; heterotopic ossification progressed from grade III immediately post-operatively to grade IV at the time of the most recent evaluation. Extra-field ossification was identified in twelve (24 per cent) of the forty-nine hips that had been irradiated preoperatively compared with three (8 per cent) of the thirty-seven hips that had been irradiated postoperatively (p = 0.05). Extra-field ossification was not associated with clinical symptoms of bursitis of the greater trochanter in any hip. Three of the ten hips that had a revision operation subsequently had a non-union of the greater trochanter; all three had been treated with preoperative irradiation. The findings of the present study suggest that pre-operative irradiation is effective for the prevention of heterotopic ossification following total hip arthroplasty and that it eliminates the discomfort and morbidity that are associated with conventional postoperative treatment. Furthermore, the efficacy of preoperative irradiation suggests that osteogenic precursor cells that are active in this process are derived from the local tissues within the operative field rather than from distant blood-borne cell lines.

Heterotopic ossification. Incidence in cemented versus cementless total hip arthroplasty

To resolve the debate whether cementless total hip arthroplasty (THA) carries an increased risk of heterotopic ossification (HO) as compared with cemented THA, 100 patients undergoing primary cemented THA (both acetabulum and femur) were individually matched to 100 patients undergoing primary cementless THA. Preoperative, 6-week postoperative, and 2-year postoperative radiographs were reviewed for the presence of HO using the Brooker classification. No subject in either group received any postoperative prophylaxis for HO. The matching parameters were age ( +/- 10 years), sex, weight ( +/- 10 lb.), diagnosis (all were osteoarthritis), Charnley class (A/B), and surgical approach (trochanteric osteotomy or modified Hardinge). The overall incidence of HO was 68% in the cemented group and 65% in the cementless group. The extent of HO (grade III) was significant in 9% of the cemented group and 5% of the cementless group. There was no grade IV HO (bone ankylosis) in either group. Neither the overall incidence nor the incidence of grade III HO was statistically different between the two groups. Patient sex and surgical approach had no interactive effect with type of component fixation on the incidence of HO. Fear of HO should not be a factor in the choice of fixation for THA.

Single-dose irradiation for the prevention of heterotopic ossification after total hip arthroplasty. A comparison of doses of five hundred and fifty and seven hundred centigray

One hundred and seven hips (ninety-four patients) that had risk factors associated with the development of heterotopic ossification after total hip arthroplasty were treated with a single dose of radiation after the operation in an attempt to prevent the formation of heterotopic bone. A study was conducted to compare the efficacy of a single dose of 550 centigray (nineteen hips) with that of a single dose of 700 centigray (eighty-eight hips). Heterotopic ossification developed in twelve (63 per cent) of the nineteen hips that were treated with 550 centigray; grades 1, 2, and 3, according to the classification of Brooker et al., developed in four hips each. Two of the patients who received 550 centigray were symptomatic. Heterotopic ossification developed in nine (10 per cent) of the eighty-eight hips that were treated with 700 centigray; the lesion was grade 1 in six, grade 2 in one, and grade 3 in two. None of the patients who received 700 centigray were symptomatic. We concluded that single-dose irradiation consisting of 550 centigray is inadequate for the prevention of heterotopic ossification in high-risk patients after total hip arthroplasty. We recommend a dose of 700 centigray as effective prophylaxis for these patients.

Heterotopic ossification in total hip arthroplasty. The influence of the approach

The effects of lateral approaches for total hip arthroplasty on heterotopic bone formation were studied in 264 patients with primary osteoarthritis. The Hardinge approach was used in 82 patients, the transtrochanteric approach in 94, and the Liverpool approach in 88. The incidence of heterotopic ossification was 42%. A severe form of bone formation occurred five times more in the Liverpool approach than in other two approaches.

Heterotopic bone formation following hip arthroplasty. A retrospective study of 65 bilateral cases

Heterotopic bone formation after two-stage bilateral cemented total hip arthroplasty was evaluated in 65 patients (23 women and 42 men) who had not received treatment with antiinflammatory drugs in the immediate postoperative weeks. The mean age at the first operation was 65 years, and the median interval between the two arthroplasties was 3 months. Fifty-two patients developed heterotopic ossification after the initial hip arthroplasty. Of these patients, 40 also developed ossifications after contralateral hip arthroplasty. Out of 11 males developing Grade-III heterotopic ossification after the initial hip arthroplasty, 8 also developed Grade-III ossification after contralateral hip arthroplasty. Two females developed Grade-III ossification after the initial arthroplasty, but neither of them developed a Grade-III lesion after contralateral total hip arthroplasty. Males with Grade-III heterotopic ossification after the initial hip arthroplasty were shown to be at a high risk of developing the same severe lesion after contralateral total hip arthroplasty, making them candidates for postoperative prophylaxis.