Effectiveness and prognostic factors of radiotherapy for painful plantar heel spurs.

BACKGROUND AND
PURPOSE: The efficacy of radiation treatment (RT) for plantar heel pain has been reported repeatedly. Yet, the results referring to the pain relief rate, to long-term effects and prognostic factors are not consistent. In this paper, the effectiveness (pain relief rate and long-term results) and prognostic factors of RT for plantar heel pain have been investigated. PATIENTS AND METHODS: From January 2000 to October 2000, 62 patients (73 heels) with painful plantar heel spurs and a minimum pain history of 3 months were treated and evaluated in a prospective study. Mean age was 54 years (range 28-84 years). All patients were treated with a total dose of 5 Gy in seven fractions (= one series), given twice a week at a single-dose sequence of 0.25-0.25-0.5-1.0-1.0-1.0-1.0 Gy (10-MV photons, source-skin distance [SSD] 100 cm, direct portal, field size 12 x 17 cm). The mean duration of heel pain before RT was 26 weeks (= 6.5 months; range 3-120 months). By means of a visual analog scale (VAS) the patients had to self-assess the quantity of their heel pain once before, three times during and four times after RT at a longterm median follow-up of 28 and 40 months. Additionally, the patients had to assess their mechanical heel stress extent during RT. Effectiveness was estimated according to the patients' judgment of pain reduction.
RESULTS: A significant reduction of heel pain extent measured by VAS has been observed already during the RT series (before RT: 6.3 +/- 1.5 vs. 3.8 +/- 2.1 at the end of RT; p < 0.001). 6 weeks after RT (FU 1) pain reduction (> 20%) was achieved in 60 heels (82.3%; n = 73), in 64 heels (91.4%; n = 70) after a mean follow-up of 28 months (FU 2), and in 61 heels (89.7%; n = 68) after a mean follow-up of 40 months (FU 3), respectively. Sufficient pain relief (> 80% compared to initial extent) was observed in 18/73 heels (24.6%) at FU 1 (FU 2: 42/70; 60.0%; FU 3: 37/68; 54.4%), including 13/73 heels (17.8%) with complete pain relief (FU 2: 39/70; 55.7%; FU 3: 36/68; 52.9%). Partial improvement (50-80% pain reduction) was observed in 27/73 heels (37.0%) at FU 1 (FU 2: 14/70; 20.0%; FU 3: 15/68; 22.1%), and minor partial improvement (20-50% pain reduction) in 15/73 heels (20.5%) at FU 1 (FU 2: 8/70; 11.4%; FU 3: 9/68; 13.2%), respectively. No change was seen in 13/73 heels (17.8%) at FU 1 (FU 2: 6/70; 8.6%; FU 3: 7/68; 10.3%). Older patients (p = 0.04) and patients who avoided heel stress during the period of RT (p < 0.01) demonstrated a better short-term response (FU 1); both effects were lost 28 and 40 months after RT. Moreover, significant differences in the extent of heel pain reduction by RT were observed in dependence on previous pain duration (at FU 2-3).
CONCLUSION: The results confirm the high efficacy of RT in painful plantar spur and add new aspects to formerly published data concerning the time course of changes in heel pain reduction. Pain relief can be expected during and shortly after RT. In addition, the initial success can be transformed into effective long-term results > 2 years after RT; however, further improvement is not to be expected. As a new prognostic factor, the reduction of mechanical heel stress during RT may ameliorate the short-term results, whereas short heel pain history improves the long-term results. Especially for older patients, RT should be taken into consideration as primary treatment.