Middle term results of tantalum acetabular cups in total hip arthroplasty following pelvic irradiation.

OBJECTIVES: The aim of this study was to evaluate the middle term cup survival, assess the functional implementation and the radiographic evolution of tantalum acetabular cups implanted on patients with a history of pelvic radiotherapy. METHODS: From 2005 to 2013, we performed 12 THA replacements (4 males 8 females; mean age: 46.6 years (range 25-75)) on irradiated bone with Trabecular metal acetabular cups, 8 primary implants and 4 revision implants. The mean radiation dose delivered was 5500 cGy (range 3000 cGy-13,600 cGy). The mean follow-up was 68 months, ranging from 38 to 136. Postoperative follow-up time was assessed at 1, 3, 6 and 12 months, then annually. Double projection radiographs were requested at each control. Radiographic signs of loosening were investigated by X-rays looking for radiolucent lines. We used the Harris hip score for the clinical and functional evaluation. RESULTS: To now none of the 12 patients in the series needed any revision surgery for aseptic loosening. In the revision group one patient have been revised for septic loosening, two patients have been treated by conservative procedure for hip dislocation. Post-operative Harris hip score improved from an average of 46 points to 85.3 points. At last follow-up we found only in one case radiographic signs of progressive lucent line, without clinical sign of failure. CONCLUSION: In a clinical setting, tantalum cup seems to provide a good stability due to the integration of the trabecular metal to the underline cancellous bone. The reported results, in agreement with literature data, propose the use of tantalum cups in irradiated bone. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Does Extracorporeal Irradiation and Reimplantation After Acetabular Resections Result in Adequate Hip Function? A Preliminary Report.

BACKGROUND: Pelvic resections are challenging, and reconstruction of the resected acetabulum to restore mobility and stability is even more difficult. Extracorporeal radiation therapy (ECRT or extracorporeal irradiation) of autograft bone and reimplantation allows for a perfect size match and has been used with some success in the extremities. Although the risk of wound complications in pelvic surgery has discouraged surgeons from using ECRT of autografts in that anatomic site, we believe it may be a reasonable option. QUESTIONS/PURPOSES: In a small series, we asked: (1) What was the median surgical time and blood loss for these procedures, and what early complications were observed? (2) Is there evidence of osteonecrosis or cartilage loss at a minimum of 2 years after ECRT of acetabular autografts, and what functional scores were achieved? (3) What were the oncologic outcomes after ECRT? METHODS: Between March 2007 and September 2016, one surgeon performed 12 ECRT acetabular autografts and reimplantations after resections of pelvic or acetabular tumors. Of those, 10 with minimum 2-year followup are reported on here with respect to oncologic, functional, and radiographic assessment; all 12 are reported on for purposes of surgical parameters and early complications. During that period, we generally performed this approach when we judged it possible to achieve a tumor-free margin, adequate bone stock, and sufficient remaining hip musculature to allow use of the bone as an autograft with restoration of hip mobility. We generally did not use this approach when we anticipated a difficult resection with uncertain margins or where remaining bone was judged of poor strength for use as a graft or if both iliopsoas and abductors were sacrificed. Since 2010, this series represents seven of the 21 pelvic resections with reconstruction that we performed (five patients in this series had the procedure performed before 2010). Followup was at a median of 65 months (range, 33-114 months) for nine patients whose functional outcomes were evaluated. The median patient age was 30 years (range, 10-64 years). Clinical parameters were recorded from chart review; radiographic analysis for assessment of cartilage was performed by looking for any obvious loss of joint space when compared with the opposite side. Functional scoring was done using the Musculoskeletal Tumor Society score, which was obtained from chart review. Oncologic assessment was determined for local recurrence as well as metastases. RESULTS: Median surgical time was 8.6 hours and median blood loss was 2250 mL. There were no perioperative wound-related complications. Two patients underwent a second surgical procedure during the postoperative period, one for a femoral artery thrombus and another for a complete sciatic nerve deficit. No patients developed avascular necrosis of the femoral head. None of the patients who underwent osteoarticular grafting showed radiographic evidence of joint space narrowing. The median Musculoskeletal Tumor Society score was 28 (range, 17-30). No fractures in the radiated segment of reimplanted bone were seen in this small series. CONCLUSIONS: Results from this small series suggest that ECRT is a potential option in selected patients who have good bone stock and adequate soft tissue coverage. Although technically challenging, ECRT is a low-cost alternative to prostheses in providing a mobile and stable hip. Although we did not observe cartilage wear on plain radiographs, followup here was short term; it may appear as we continue to follow these patients. Future studies from retrieval specimens may shed light on the actual status of cartilage on the acetabulum. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Poor Utility of Gonadal Shielding for Pediatric Pelvic Radiographs.

Plain pelvic radiographs are commonly used for a variety of pediatric orthopedic disorders. Lead shielding is typically placed over the gonads to minimize radiation exposure to these sensitive tissues. However, misplaced shielding can sabotage efforts to protect patients from excessive radiation exposure either by not covering radiosensitive tissues or by obscuring anatomic areas of interest, prompting repeat radiographic examinations. The goal of this study was to determine the incidence of misplaced shielding for pelvic radiographs obtained for pediatric orthopedic evaluation. Children 8 to 16 years old who had an anteroposterior or frog lateral pelvic radiograph between 2008 and 2014 were included. A total of 3400 patients met the inclusion criteria, and 84 boys and 84 girls were randomly selected for review. For both boys and girls, the percentage of incorrectly positioned or missing shields was calculated. Chi-square testing was used to compare the frequency of missing or incorrectly placed shields between sexes and age groups. Pelvic shields were misplaced in 49% of anteroposterior and 63% of frog lateral radiographs. Shielding was misplaced more frequently for girls than for boys on frog lateral radiographs (76% vs 51%; P<.05). Pelvic bony landmarks were often obscured by pelvic shielding, with a frequency of 7% to 43%, depending on the specific landmark. The femoral head and acetabulum were obscured by shielding in up to 2% of all images. The findings suggest that accepted pelvic shielding protocols are ineffective. Consideration should be given to alternative protocols or abandonment of this practice. [Orthopedics. 2017; 40(4):e623-e627.].

Prophylactic radiotherapy against heterotopic ossification following internal fixation of acetabular fractures: a comparative estimate of risk.

OBJECTIVE: Radiotherapy (RT) is effective in preventing heterotopic ossification (HO) around acetabular fractures requiring surgical reconstruction. We audited outcomes and estimated risks from RT prophylaxis, and alternatives of indometacin or no prophylaxis. METHODS: 34 patients underwent reconstruction of acetabular fractures through a posterior approach, followed by a 8-Gy single fraction. The mean age was 44 years. The mean time from surgery to RT was 1.1 days. The major RT risk is radiation-induced fatal cancer. The International Commission on Radiological Protection (ICRP) method was used to estimate risk, and compared with a method (Trott and Kemprad) specifically for estimating RT risk for benign disease. These were compared with risks associated with indometacin and no prophylaxis. RESULTS: 28 patients (82%) developed no HO; 6 developed Brooker Class I; and none developed Class II-IV HO. The ICRP method suggests a risk of fatal cancer in the range of 1 in 1000 to 1 in 10,000; the Trott and Kemprad method suggests 1 in 3000. For younger patients, this may rise to 1 in 2000; and for elderly patients, it may fall to 1 in 6000. The risk of death from gastric bleeding or perforation from indometacin is 1 in 180 to 1 in 900 in older patients. Without prophylaxis risk of death from reoperation to remove HO is 1 in 4000 to 1 in 30,000. CONCLUSION: These results are encouraging, consistent with much larger series and endorse our multidisciplinary management. Risk estimates can be used in discussion with patients. ADVANCES IN KNOWLEDGE: The risk from RT prophylaxis is small, it is safer than indometacin and substantially overlaps with the range for no prophylaxis.

A case of spontaneous hip dislocation that occurred during radiation therapy.

Currently, radiation therapy is widely used for the treatment and palliation of metastatic bone disease in both adults and children. Recent advances in radiation therapy, such as intensity-modulated radiation therapy, have led to more focused treatments and fewer adverse effects. Although radiation therapy has been associated with several musculoskeletal effects in the growing child, hip dislocation during a course of radiation therapy has not been reported. We report a case of a 12-year-old girl who presented with metastatic bone disease, and developed a hip dislocation during radiation therapy. Possible causes are discussed in detail and a thorough literature review is presented.

Encountering cancer or its sequelae at the hip.

The orthopedist may need act as an adjunct to the medical oncologist in the management of the cancer patient with hip disease. While management of the cancer patient with routine hip pathology is relatively straightforward, the surgeon should be aware that the cancer patient may be on treatment protocols that affect wound healing, the immune system, and the risk of deep venous thrombosis. An additional factor that may complicate management of patients who have completed treatment of peripelvic cancer may be local radiation therapy, which can lead to necrosis of the acetabular bone stock. Operating on these patients must include consultation with previous radiation therapy providers to estimate the dose sustained by the local tissues under consideration. Greater than 500 cGy has been associated with high fixation failure rates in several series. Increased rates of infection and wound healing have also been noted secondary to long-term lymphatic obliteration caused by radiation. These concerns also affect the surgeon who must manage patients with acute metastatic disease. The principles of managing metastatic disease include recognizing the presence of lesions in bone about the hip, the occasional need for biopsy, the use of radiation in sensitive tumors, surgical stabilization of impending fracture, or joint replacement when needed. The amount of tumor, as well as the effect of chemotherapy and radiation on the healing process, potentially complicates these treatment modalities.

[Value of a combined ossification prophylaxis with indomethacin and radiotherapy for acetabular fractures]. / Wertigkeit einer kombinierten Ossifikationsprophylaxe mit Indometacin und Bestrahlung bei Azetabulumfrakturen.

BACKGROUND: Heterotopic ossification is a complication in patients with surgically treated acetabular fractures. The incidence is related to the surgical approach (extended iliofemoral, posterior or a combined approach). The objective of this study was to evaluate the incidence of heterotopic ossification in patients with acetabular fractures who received a combined prophylaxis with both a single dose of radiation and indomethacin compared to those who received only a prophylaxis with radiation or indomethacin. PATIENTS AND METHODS: A total of 24 patients with a combined prophylaxis after surgery were examined retrospectively 24 months after trauma. A systematic literature review was performed and our own results were compared with different methods for prophylaxis of heterotopic ossification from the literature. RESULTS: Only one patient developed a heterotopic ossification. In accordance with the literature, combined prophylaxis showed the least incidence of ossification compared to the other methods. Differences in incidence frequencies were significant between the different prophylaxis methods. CONCLUSION: A combined prophylaxis for heterotopic ossification in surgically treated acetabular fractures seems to be a better alternative than a prophylaxis with radiation or indomethacin alone.

Latent period best predicts acetabular cup failure after total hip arthroplasties in radiated hips.

UNLABELLED: We retrospectively analyzed the prognostic factors related to the failure of acetabular components after total hip arthroplasties in radiated hips. Eighteen hips from 12 patients who had primary arthroplasties were followed up for a mean of 58 months (range, 20-139 months). The patients' age, total radiation dose, latent period, presence of infection, and the type of the acetabular component were examined as possible predictors of failure using the Cox proportional hazard regression. Multivariate analyses showed that a longer latent period was the most important risk factor for failure, increasing 1.72 times when the latent period was greater than 1 year, after adjusting for other predictors. The latent period might be helpful for clinicians in choosing a treatment method for patients. LEVEL OF EVIDENCE: Prognostic study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Acetabular augmentation induced by extracorporeal shock waves in rabbits.

We conducted this animal study to demonstrate whether exposing the acetabulum in immature rabbits to extracorporeal shock waves induces bone formation in the acetabulum. Five thousand shock waves of 100 MPa each were directed, from outside, at the acetabular roof of eight immature rabbits. At each of two time points (4 and 8 weeks) after treatment, the pelvises of four rabbits were removed and evaluated morphologically. Woven bone formation was observed on the lateral margin of the acetabular roof at 4 weeks after treatment, and the breadth of the acetabular roof in the coronal plane was significantly increased. Eight weeks after treatment, the woven bone disappeared; the breadth of the acetabular roof, however, was significantly increased. These findings demonstrated that extracorporeal shock waves induced acetabular augmentation in rabbits. We conclude that extracorporeal shock waves, perhaps, could be applied clinically for the treatment of acetabular dysplasia.

Bone HDR brachytherapy in a patient with recurrent Ewing's sarcoma of the acetabulum: alternative to aggressive surgery.

A 17-year-old girl diagnosed with a previously irradiated, locally recurrent Ewing's sarcoma involving the puboischiatic rami and the adjacent acetabulum was referred to our institution for consideration of salvage hindquarter resection. A conservative resection with implantation of the acetabular remnant for high-dose rate brachytherapy was performed instead. The patient died 11 months after surgery without signs or symptoms of bony damage and retained the ability to walk for the remainder of her life.

Therapeutic percutaneous injections in the treatment of malignant acetabular osteolyses.

Percutaneous injection of methylmethacrylate or ethanol may provide marked pain relief or bone strengthening in patients with malignant acetabular osteolyses who are unable to tolerate surgery. Injection of methylmethacrylate is usually indicated when osteolysis involves the weight-bearing part of the acetabulum (ie, the acetabular roof); in all other cases, ethanol injection is preferred. Ethanol and methylmethacrylate injections may be performed together if both weight-bearing and nonweight-bearing parts of the acetabulum are involved or extensive soft-tissue involvement is present. Moreover, these injections may be performed prior to radiation therapy, which complements their action due to similar but delayed effects on pain, or after radiation therapy that failed to relieve pain or in cases of local recurrence. Radiography and computed tomography must be performed prior to therapeutic percutaneous injection to assess the location and extent of the lytic process, the presence of cortical destruction or fracture, and the presence of soft-tissue involvement. Fever and transitory worsening in pain may occur secondary to inflammatory reaction in the hours following injection; however, these side effects usually resolve spontaneously within 1-3 days. The decision to perform therapeutic percutaneous injections should be made by a multidisciplinary team because the choice between this option and alternative methods of treatment depends on several factors including the location of the lesion, the local and general extent of the disease, the pain and functional disability experienced by the patient, and the patient's state of health and life expectancy.

POEMS syndrome in a 24-year-old man associated with vitamin B12 deficiency and a solitary lytic bone lesion.

We report one of the youngest cases of POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes), presenting in a 24-year-old man. A solitary lytic bone lesion and vitamin B12 deficiency were also found. We suggest that this syndrome be considered in cases of subacute polyneuropathy developing in young adults.

Early failure of acetabular components inserted without cement after previous pelvic irradiation.

The effect of previous irradiation of the pelvis on the survival of acetabular components inserted without cement in primary total hip arthroplasty was examined. We searched a database of 1319 patients who had been managed with a primary total hip arthroplasty with insertion of a hemispherical porous-coated acetabular component without cement. This revealed twelve hips in eleven patients who had been managed with previous irradiation of the pelvis. Three patients had died after less than one year of follow-up, leaving eight patients with nine acetabular components available for study at an average of thirty-seven months (range, seventeen to seventy-eight months) after the operation. The type of radiation as well as the fractionation, dose, and portals were reviewed to determine the exposure of the periacetabular region to radiation. Failure of the component was assessed radiographically and clinically. At the time of follow-up, three of the nine acetabular components had migrated, as seen on radiographs, and had been associated with progressive radiolucency without clinical symptoms. Thus, four of the nine acetabular components failed, at an average of twenty-five months (range, sixteen to thirty-eight months). The other five components had not failed clinically and were stable radiographically at an average of thirty-six months (range, seventeen to sixty-three months). The insertion of acetabular components without cement in a previously irradiated pelvis has a high rate of failure. However, a superior method of acetabular reconstruction in this difficult situation has yet to emerge.

[3-years results of endoprosthetic management of radiation-induced hip joint necrosis]. / 3-Jahresergebnisse nach endoprothetischer Versorgung strahleninduzierter Hüftgelenksnekrosen.

Radioosteonecrosis of the acetabulum is a rare side effect of radiotherapy. The latency period of 2 to 17 years is much longer than that reported for other bones (1-3 years). The reason for this is unknown. Plane radiograms show sclerosis, cysts and fractures of the acetabulum and, in most cases, a migration of the femoral head with flattening. The diagnosis of a radioosteonecrosis has to be made by exclusion of malignomas by scintigraphy and MRT or CT. This paper presents the follow-up of four patients treated by total hip replacement (THR) for radioosteonecrosis of the acetabulum. Within 9 months postoperatively the fractures of the acetabulum had healed with full weight bearing. 36 to 78 months after operation no signs of progression of the bone changes were detected. In this period the loosening of one spherical thread cup occurred, but a radiolucent gap above a cemented cup stayed unchanged. We conclude that irradiation damage of the acetabulum can be treated successfully by THR even in cases with fractures of the acetabulum as far as a stable implantation can be achieved and the remaining osteoblasts are preserved by the procedure.

Does decreased skeletal uptake of 99mTc-methylene bisphosphonate in irradiated bone indicate the absence of bone metastases?

Reduced uptake of 99mTc-methylene bisphosphonate (99mTc-MBP) was found in irradiated bone in all of 13 tumour-free patients who had undergone radiotherapy (30-40 Gy) due to seminoma 3-8 years prior to bone scintigraphy. Decreased uptake of 99mTc phosphate compounds can not per se be interpreted as a sign of absence of metastases or reduced tumour burden.

[Osteoradionecrosis at the level of coxo-femoral articulation in the adult]. / Radionécrose au niveau de l'articulation coxofémorale chez l'adulte.

Two cases of either cervical or acetabular osteoradionecrosis were described. One patient had endoprosthetic replacement of the hip, the other did not receive any surgical treatment. Regarding the literature, osteoradionecrosis occurs in 0.3 to 4% of the irradiated bones. Histologically there is a destruction of the bone by direct toxicity of the radiation and by destruction of the vascular supply. The threshold of irreversible bone destruction is 30 Gy. Fractures are epiphenomenons of osseous radionecrosis. The diagnosis can be suspected either by radiographies or by bone scans. Sometimes a bone biopsy is necessary to differentiate between bone necrosis, bone metastasis and eventually a radiation-induced sarcoma of the bone. If the osteoradionecrosis affects the acetabulum, even in the case of a stress fracture without acetabular protrusion of the femoral head, no surgical treatment is recommended. Weight bearing is avoided and spontaneous resolution occurs in most cases. If, on the other hand, there is a fracture through the femoral neck, hemiarthroplasty or total joint replacement is the treatment of choice. Total joint replacement is also recommended in case of an extensive radiation induced coxopathy.

Stature loss following skeletal irradiation for childhood cancer.

A model is presented to predict adult stature in children treated successfully for cancer outside the CNS. The model is based on radiation dose in Gray adjusted for location of therapy and attained stature (GALA); ideal adult stature (IAS), assuming the patient had not developed cancer, calculated by the Roche-Wainer-Thissen (RWT) method (which uses patient stature and weight before developing cancer, and parent stature data); a femur correction if both the acetabula or heads of both femurs were irradiated (FEMUR); and sex. The model was constructed using data from 49 patients with a mean time from completion of therapy to follow-up of 8.9 years (range, 3.3 to 15.4 years). Thirteen patients received no radiotherapy. All model coefficients were highly significant (P less than .001), and the model appears to be an excellent predictor of adult stature, with a multiple correlation coefficient of 0.84 (R2 = .74) between corrected adult stature (CAS) based on the most recent follow-up stature available for the patient projected to final adult stature, compared with the model's predicted adult stature (MPAS), based only on initial data at presentation and subsequent radiation treatment. Patients who did not receive radiotherapy did not have loss of stature, ie, there was no significant difference between IAS and CAS, (P less than .71; n = 13), but patients who received radiotherapy had shorter statures than would be expected from the healthy population model (P less than .0004; n = 36). The magnitude of the loss in stature appears to be well explained by the dose and location of radiation, the stature already achieved at the time of radiotherapy, along with IAS, FEMUR, and sex. We believe this model will help clinicians to predict the growth effects of radiotherapy in children with cancer not involving the CNS.

Osteonecrosis, fractures, and protrusio acetabuli secondary to x-irradiation therapy for prostatic carcinoma.

Two years after pelvic irradiation for prostatic cancer, bilateral protrusio acetabuli and collapse of the right femoral head requiring prosthetic arthroplasty developed in a 73-year-old man with chronic rheumatoid arthritis. There was no evidence of metastases. Histologic evaluation showed empty lacunae in the bone but no evidence of obliterative endarteritis. Osteonecrosis and pathologic fractures constitute a rare complication of high voltage irradiation.

[Radiation lesions of the hip]. / Les radio-lésions de la hanche

Irradiation lesions of the hip are much better known than they used to be, and problems diagnosis no longer arise. Study of these 49 cases of irradiation lesions of the hip shows that they occur in 1 to 36 per cent of patients irradiated for pelvic cancer. The rate of occurrence may be reduced by selection and improvement in the techniques of radiotherapy. The extent of the lesions is determined from the time that irradiation is stopped. The lesions appear after a delay of several months and develop progressively throughout their extent. This confer on them a false appearance of a progressive lesion. There are severe lesions, which seriously threaten ambulation. Trans-cervical fractures should be considered separately; these are usually isolated lesions, simple to treat and of good prognosis. Fractures of the acetabulum and necroses of the acetabular roof or of the femoral head, developing usually as paired lesions or in the context of an irradiation coxopathy, constitute another group, in which treatment by total prosthesis raises numerous technical problems. Total prosthesis has however given to these hips; in almost 2 cases out of 3, a function which is at present satisfactory but whose future is unknown. The abnormality high levels of infection and in particular loosening are related to the extent to which the lesions have progressed. Resection of these prosthesis in cases of failure is similar to resection of the head and neck, and has its place as a salvage operation since its allows mobility and pain relief to be obtained at the price of stability.

Bilateral protusio acetabuli following pelvic irradiation.

A 77 year old man developed bilateral protrusio acetabuli three years following pelvic irradiation for transitional cell carcinoma of the prostatic urethra. There was no evidence of metastasis or coexistent systemic arthritis. Aseptic necrosis of acetabular bone is the postulated etiology. Gross and pathologic evidence of aseptic necrosis of both femoral heads was observed. Vascular fibrosis was a prominent pathologic finding, as was eosinophilia of the synovial fluid and joint tissue. Protrusio appears to be an infrequently described complication of pelvic irradiation.