A randomized clinical study of the heated lidocaine/tetracaine patch versus subacromial corticosteroid injection for the treatment of pain associated with shoulder impingement syndrome

Figures & data

Figure 1 CONSORT flow diagram.

Abbreviations: HLT, heated lidocaine/tetracaine; CONSORT, Consolidated Standards of Reporting Trials.

Table 1 Baseline patient characteristics

	Treatment group		P-value
	HLT patch	Injection
Number of patients	29	31
Age (years)
Mean ± SD	50.5±12.1	51.4±10.2	0.765
Range	28–72	18–75
Male:female	17:12	22:9
Baseline pain scores (mean ± SD)
Average pain	6.0±1.6	5.6±1.2	0.329
Worst pain	7.4±1.5	7.4±1.1	0.782
Baseline interference scores (mean ± SD)
General activity	5.8±2.3	5.4±1.7	0.517
Normal work	5.3±2.2	5.4±1.9	0.937
Sleep	6.4±2.4	6.5±2.3	0.906
Shoulder range of motion (mean ± SD)
Internal rotation (°)	36.4±27.0	28.9±24.0	0.259
Abduction (°)	90.9±29.8	94.7±32.6	0.639

Abbreviations: HLT, heated lidocaine/tetracaine; SD, standard deviation.

Figure 2 The effect of the HLT patch or subacromial corticosteroid injection on (A) “average pain”, and (B) “worst pain” scores in patients with SIS.

Notes: Patients in the injection group were treated with a single subacromial corticosteroid injection on day 0. Starting on day 0 and through day 14, patients in the HLT patch group were treated with a single patch applied to the painful area of the shoulder for a period of 3 to 4 hours twice daily. During the second 14-day period, patients in the HLT patch group were allowed to use the patch as needed up to twice daily as described for the initial 14-day study period. No treatment was applied during the final 14-day period. *P<0.001 compared with baseline.
Abbreviations: BID, twice daily; HLT, heated lidocaine/tetracaine; PRN, as needed; SD, standard deviation; SIS, shoulder impingement syndrome.

Figure 3 Cumulative response curves for the percentage reduction in average pain score from baseline to day 42. The dotted lines represent the 30% and 50% thresholds for reduction in pain scores.

Abbreviation: HLT, heated lidocaine/tetracaine.

Table 2 Effect of treatment on pain interference scores

	Day 1	Day 14	Day 28	Day 42
HLT patch (n=29)
General activity	5.8±2.3	3.5±2.4a	3.0±2.5a	2.8±2.6a
Normal work	5.3±2.2	3.2±2.4a	2.8±2.6a	2.6±2.7a
Sleep	6.4±2.4	3.6±3.0a	3.4±3.0a	3.1±3.1a
Injection (n=31)
General activity	5.4±1.7	3.4±2.7b	3.4±2.8b	3.1±2.9a
Normal work	5.4±1.9	3.3±2.6b	3.2±2.8b	2.9±2.7a
Sleep	6.5±2.3	3.2±3.0a	3.4±3.2a	2.9±3.2a

Notes: Values expressed as mean ± standard deviation.

a P<0.001 compared with baseline (day 1);

b P<0.01 compared with baseline (day 1). No statistically significant between-group changes were found.

Abbreviation: HLT, heated lidocaine/tetracaine.

Figure 4 Effect of treatment on shoulder range of motion.

Note: *P<0.001 compared with baseline.
Abbreviations: HLT, heated lidocaine/tetracaine; SD, standard deviation.

Figure 5 Cumulative shoulder range of motion at baseline and day 42.

Note: Vertical dotted lines represent the normal shoulder range of motion.
Abbreviation: HLT, heated lidocaine/tetracaine.