Table 1.

Summary of results

Reference	Study type	Number of patients	Stage	Pre-treatment hip outcome score	Aetiology	Clinical technique	Additional management	Results	Post-treatment hip outcome score	Other
J.L. Cebrián et al. [3].	Retrospective	51 (70 hips)	ARCO staging used. I: 20 II: 50	Symptomatic, AVN + no collapse on MRI and X-ray	Idiopathic: 40 Steroids: 26 Alcohol: 4	1 pair of coils attached anteriorly & posteriorly, held in place over greater trochanter on molded splint. Single pulse of Frequency: 75 Hz Intensity: 400 mA Time: 1 at 3 ms Duration of tx: Coils worn for 8 h/day for 6 months	-	Follow up at 3, 6, 12, 24, 48 months with AP + Axial X-ray and MRI. Mean follow-up = 26 months. Collapse ARCO I + IIA: 0 collapse ARCO IIB: 3 collapse ARCO IIC: 5 collapse D’Aubigne pain scale Improve: 55 Stable: 11 Decline: 4	80% had radiological success. 88.57% had no progression. 11.43% collapsed.	Progression = ↑ARCO stage or collapse >2 mm compared to pre-treatment
L. Massari et al. [4]	Prospective	68	Steinberg staging used	-	Primary: 34 Steroids: 17 Trauma: 5	SPT BIOSTIM pulse generator used. Single voltage pulses Frequency: 75 Hz Time: each pulse at 1.3 ms Duration of tx: 8 h/day for 6 months	Core decompression and autologous bone graft (from proximal metaphysis and femoral neck)	X-ray and MRI at 1, 3, 6, 12, 24 months from surgery. After, X-ray yearly and MRI every 2 or 3 yr. Mean follow-up = 5.8 yrs. Steinberg II: 81% no pain and limping, good radiographic results. Steinberg III: 70% success Steinberg IV: 53% good clinical results. 27% good radiographic results.		2 patients needed total hip arthroplasty: - Bilateral in 1 patient (Steinberg III) - Unilateral in 1 patient (Steinberg IV)
L. Massari et al. [2]	Retrospective	66 (76 hips)	Ficat staging used. I: 31 II: 22 III: 23	1/3 were Ficat stage III Intense pain and significant functional restriction	Primary: 51 Secondary (alcohol, trauma, steroids): 15	SPT BIOSTIM pulse generator used: Duration of tx: 8 h/day for 6 months (mean duration = 5+/−2 months)	NSAIDS for pain. Non-weight bearing advised but only 50% complied.	Mean follow-up = 28 months X-ray at follow-up with CT and MRI confirmation if available. Ficat I + II: 50/53 hips preserved; 3 Ficat II had progression Ficat III: 12 hips had progression Ficat I: 45% improved to stage 0; 45% unchanged; 10% worsened to stage II Ficat II: 35% improved to stage I; 50% unchanged; 25% worsened to stage III Ficat III: 0% improved; 50% unchanged; 50% worsened to stage IV	15 of 76 hips progressed. Pain - 35 were pain free after 60 days of treatment. - 17 had pain of moderate intensity. - 14 still had intense pain. Hip joint function - Normal in 46% - Sufficient in 39% - Insufficient in 15%	The hips that progressed led to severe degenerative OA that required surgery.
C. Windisch et al. [5]	Prospective	35	ARCO staging used. Group 1 IIA: 3 IIB: 8 IIC: 7 IIIC: 4 Group 2 (non-PEMF) IIA: 4 IIB: 9 IIIB: 2 IIIC: 3	Group 1: 3/19 pts. had bilateral involvement Group 2: 2/16 had bilateral involvement	-	Magnetodyn – external magnetic field coil and an invasive bipolar induction screw. Frequency: Sinus shaped external magnetic field of ~20 Hz Magnetic flux density: ~5mT Voltage: ~700 mV induced Electric field strength: 50-700 mV/cm	Curettage, autologous bone grafting (from greater trochanter and proximal femur).	Follow-up checks at 6 and 12 months: clinical exam, clinical evaluation – modified Harris Hip score, Merle D’Aubigne hip score, VAS; imaging – X-ray with pelvic view and axial projection of hip, bilateral MRI. Group 1: - 2 stage 2C patients had THA - 2 stage 3C patients had THA Group 2: - 1 stage 2B patient had THA - 1 stage 3B patient had THA - 2 stage 3C patients had THA Comparing clinical outcomes of group 1 and 2: - No significant difference between groups for D’Aubigne score. - No significant difference in Harris Hip score. - No significant difference in VAS. - No significant improvement/deterioration as a result of the procedure in group 1. - Both procedures promising up to stage 2A.		18% of patients in Group 1 had to have THA. 22% of patients in Group 2 had to have THA.
M.E. Steinberg et al. [11]	Prospective	285 (406 hips)	Steinberg staging used. I: 62 hips II: 133 III: 13 IV: 85 V: 4	-	Primary: 10% Steroids: 38% Alcohol: 37% Alcohol + Steroids: 15% Trauma: 12%	Group 1: Constant DC via cathode wire coiled about the graft and attached to an Osteostem/ Orthofuse Group 2: Capacitative coupling via surface electrodes applied anteriorly and posteriorly to the skin over the femoral head and connected to a portable power unit.	Core decompression and bone grafting	Post-operative evaluation by Harris Hip score, AP + lateral X-rays, taken at 3, 6,12, 18, 24 months and then yearly/two yearly thereafter. Mean follow-up = 46 months DC group - Radiographic progression in 70%. - Mean progression: 2/3 stage - Mean 5 point improvement in HHS (64% improved or remained unchanged) - 41% needed THA Control - 79% radiographic progression - Mean progress: 1 1/3 a stage - Mean 3 point drop in HHS - 43% improved or unchanged - 37% needed THA Capacitive coupling - Clinically and radiographically, 42% improved or remained unchanged - 25% needed THA Control - Radiographically and clinically, 50% improved or remained unchanged - 20% needed THA	-	-
M.E. Steinberg et. Al [15]	Prospective + historical control	116 hips 55 hips for historical controls 40 hips for disease progression (separate studies)	Steinberg staging used. Mean stages: Non-stimulated: IIIA Stimulated: IIIB	Non-stimulated: IIIA Stimulated: IIIB Mean Harris scores Non-stimulated: 65 Stimulated: 65	-	Constant DC electrical stimulator coiled longitudinally, delivering Intensity: 20microA Duration: 24 h a day for 6 months.	Core decompression and grafting	Mean follow up time = Non-stimulated: 33 months Stimulated: 44 months Electrical stimulation gave better Harris scores, less roentgenographic progression, but similar need for arthroplasty. No fractures or complications	No electricity: IVB Electricity: IVA Mean Harris scores No electricity: 62 Electricity: 70	Nil
Bassett et al. [10]	Prospective	95 (118 hips)	Steinberg staging used. I: 0 II: 12 III: 3 IV: 79 V: 21 VI: 3	Charnley modification of Merle D’Aubigne-Postel system Mean scores = Pain:3.9 Function: 3.7 Mobility: 5.2 Total: 12.8	Primary: 44 Trauma: 17 Alcohol: 9 Steroid: 46 Sickle cell: 2	Helmholtz-aiding coils, mounted anteriorly & posteriorly on splint. 7″ diameter coils, 6–8″ apart on brace. Single 12″ diameter contoured coil on femoral head with Velcro around pelvis. Duration: 8–10 h/day, discontinued ″1 year. No changes with weight-bearing	Nil	Mean follow up = 5.3 years; every 2/3 months in 1st year, then 3–6 months after PEMF treatment. Average 4.1 years prior. 9 hips (60%) in Stage II-III improved (3 returned to normal), 90 (76%) hips in stages IIA to VI stayed same, 19 (16%) in IVA to VC worsened (<2 mm collapse). Joint space width increased on average 1 mm in 17 of these 19, but most of these showed clinical improvement	One year: 15 Most recent: 15.8	20 required surgical procedures
R.K. Aaron et al. [6]	Prospective	77 (106 hips)	Ficat staging used. PEMF II: 23 III: 33 Core decompression II: 26 III: 24	Modified D’Aubigne scale: actual scores not given	-	Coil positioned over greater trochanter. Single pulse Frequency: 72 Hz, quasirectangular, 380microsec. Duration: 8 h/day, 12–18 months.	Core decompression in non-PEMF group	Mean follow-up = 3 years Percentage demonstrating both clinical & roentgenographic success PEMF: 52% Core: 20%	Clinical success (based on Modified D’Aubigne scale): PEMF: 38 hips (68%) Core decompression: 22 hips (44%)	Nil
Steinberg et al. [14]	Prospective + historical control	40 (40 hips) 55 control hips	Steinberg staging used. Stimulated I: 3 II: 16 III: 1 Non-stimulated I: 4 II: 16	Harris score Stimulated: 94 Unstimulated: 75 Mean stage: Stimulated: IIB Unstimulated: IIA	Steroids: 19 Alcohol: 13 Other: 4 Idiopathic: 4	2 capacitive-coupling units (self-adhering electrodes) over femoral head Frequency: 60 kHz Duration: 24 h Intensity: 5 V peak-peak amplitude.	All 40 patients had core decompression + grafting	Harris score Stimulated: 82 Unstimulated: 76 Clinically unchanged Stimulated: 42% Unstimulated: 50% Mean stage Stimulated: IIIA Unstimulated: IIIA No significant difference Comparison with conservative Core: 54% progress, 23% required total hip arthroplasty Conservative: 81%progress, 69% required total hip arthroplasty	-	25% of stimulated & 20% of unstimulated hips required total hip arthroplasty.
R.K. Aaron et al. [2, 6].	Prospective	264 (373 hips)	Steinberg staging	Radiographic progression	-	PEMF	-	Mean follow-up = 35 months Stage I: all hips conserved. 75% radiographic progression Stage II: 77% preserved. 54% radiographic progression Stage III: 53% preserved. 68% radiographic progression	-	-

AVN Avascular Necrosis, ARCO Association Research Circulation Osseous, CD Core Decompression, PEMF Pulsed Electromagnetic Field, DC Direct Current, NSAIDs Non-steroidal Anti-Inflammatory Drugs