Radiation prophylaxis as primary prevention of heterotopic ossification of the knee: classification of disease and indications for treatment

Abstract

Objective Heterotopic ossification (HO) of the knee joint is seen in up to 42 % of patients following total knee arthroplasty (TKA). Despite this prevalence, there is a paucity of data to validate the efficacy and after effects of prophylactic radiotherapy (PRT) to the knee to prevent HO. We report retrospectively our institution's experience with 12 patients treated with PRT of the knee joint. We also present a classification scheme and review the indications for PRT following TKA. Methods Between 1999 and 2010, 112 patients were treated at our institution with PRT for prevention of HO. Of these patients, 12 underwent PRT to the knee joint and were included in our analysis. All patients were treated with one fraction of PRT to a total dose of 700 cGy. Primary end points were joint range of motion (ROM) and HO formation. ROM was evaluated as "limited" or "full" by the patient's surgeon or primary care provider at the most recent follow-up examination. The most recent radiograph was evaluated for presence of HO. Results With a median follow-up time of 78 months (range, 1-132 months), 0/12 patients had evidence of HO on x-ray imaging. Full ROM was documented in 11/12 patients. One patient had limited ROM at the most recent follow-up due to severe osteoarthritis. No patient had impaired mobility or ROM directly attributed to fibrosis or late effects of PRT. Conclusion Based on our retrospective analysis, PRT appears to be a safe, effective treatment for prophylaxis of HO in the knee joint.

Radiation Therapy Prophylaxis for Heterotopic Ossification in Non-Hip Sites

“…Overall, there were no toxicities, acute or late, noted. One report from Drexel University with 12 patients who underwent RT for knee HO prophylaxis had no HO recurrence after treatment [8]. This patient group differed from ours as 8 (61.5%) of our patients versus none of their patients had evidence of HO prior to surgery.…”

“…There are multiple case reports and a retrospective study with 12 patients [8]- [15]. The development of HO has been noted after total knee arthroplasty in up to approximately 40% of patients [9] [10] [11] [12].…”

Successful Total Knee Arthroplasty in a Patient With Contralateral Ankylosis Due to Severe Heterotopic Ossification

“…One of the first published cases on HO prophylaxis of the knee is by Lo et al, who reported successful radiation prophylaxis with 7 Gy after revision TKA in a patient who developed symptomatic HO following initial TKA [ 16 ]. Subsequent studies reported no recurrence of HO with 7 Gy of postoperative radiation in high-risk patients and those who underwent HO excision [ 6 , 17 ]. Some studies have proposed non-steroidal anti-inflammatory drug use as attributing factors to the low incidence of HO after TKA [ 12 , 15 ].…”