Heterotopic ossification after total hip arthroplasty: When is development completed?

BACKGROUND: Heterotopic ossifications (HO) are a common complication after total hip arthroplasty (THA). Nonsteroidal anti-inflammatory drugs have proven to reduce the occurrence of HO. It is still unclear when the formation of HO is finished. Aim of our study was to answer this question. METHODS: In a prospective study, the occurrence of periarticular HO was checked during the follow-up (FU) examinations. In total, 75 consecutive patients who underwent THA were included. To ensure a high follow-up rate, only patients with a life expectancy of at least 10 years were included. A medical ossification prophylaxis with mostly etoricoxib (90 mg once daily) was administered. Follow-up examinations were performed at 3 months, 1 year, 3, 5, and 10 years postoperatively. Each time, a clinical and radiological examination was carried out. The HO was graded according to Brooker's method. RESULTS: Low-grade HO classified by Brooker grade I and II occurred significantly more frequent than HO grade III. In patients with present HO, a possible increase in Brooker stage could further be observed within 3 years postoperatively. After 3 years, the formation of HO was completed in all patients. CONCLUSION: Three years after THA, the formation of HO is complete. After more than 3 years postoperatively, if HO occurs or increases, other triggering causes such as new trauma, periarticular infection, or implant loosening should be considered.

Etoricoxib is safe and effective in preventing heterotopic ossification after primary total hip arthroplasty.

BACKGROUND: Heterotopic ossifications are a common complication after total hip arthroplasty. Low-dose radiation therapy and non-steroidal anti-inflammatory drugs have proven to effectively reduce the rate of heterotopic ossification after total hip arthroplasty. However, a low number of studies describe an equal efficiency of etoricoxib. This work shows first results on the examination of a larger group with 194 subjects to analyze efficiency and rate of side effects under treatment with etoricoxib. METHODS: Clinical examinations were performed the day before surgery and after at least 12 months. The survey of clinical and functional outcome was done with Harris Hip Score (HHS). Conventional antero-posterior radiographs and second plane in frog leg position were assessed. RESULTS: In total, 14 undesirable side effects (7.4%) and only four early terminations of therapy (2.1%) were documented. A complete 1-year follow-up examination including radiographs could be done in 143 subjects (79.4%). Only 28 subjects (19.6%) developed heterotopic ossifications from which 92.9% were classified in type 1 and 7.1% in type 2 using the method described by Brooker. The results do not show correlations with body mass index, extended treatment (more than ten days), or clinical and functional outcome (measured by "Harris Hip Score"). However, male subjects show a significantly higher rate of heterotopic ossifications. CONCLUSIONS: The investigations presented in this study confirm a good efficiency of etoricoxib for the prevention of heterotopic ossifications in comparison with classical methods such as radiation or drug therapy and show a low rate of undesirable side effects.

Anatomical and surgical study of volume determination of the anterolateral epidural space nerve root L5/S1 under the aspect of epidural perineural injection in minimal invasive treatment of lumbar nerve root compression.

Herniated intervertebral disc causes in a great number of cases of lumbar nerve root compression, especially in the segment L5/S1. Other reasons responsible for stress to the lumbar spinal root are the spinal canal stenosis and the postdiscotomy syndrome. For patients without neurological deficiencies, the conservative treatment includes different epidural injection techniques. Steroids are often applied. A specific injection technique needing only a small drug amount is the epidural perineural approach using a special two-needle technique. The anatomical spaces of the nerve roots have received little attention in therapy. We have determined the anterolateral epidural space nerve volume of the nerve root L5/S1, and compared the data collected in an anatomical study with operative measurements during discectomy. The volume determination in the human cadavers was performed with liquid silicone filling the anterolateral space after dissection. The in vivo measurements were performed during surgery at the site of the anterolateral space after discectomy. The anatomical studies showed us a mean value volume of 1.1 ml. The surgical volume determinations result in a mean volume of 0.9 ml. A better understanding of the anterolateral epidural space may allow a reduction of the injection volume in the conservative nerve root compression treatment, especially using the epidural perineural technique, avoiding the risk of side effects of high doses of steroids.