Johann Georg Mönckeberg was a Hamburg patrician, born in 1877. His father — same name — was a senator of the free city, with the Mönckebergstrasse running from the Rathaus to the Hauptbahnhof named after him. The son grew up in a household where the name was already on the streets. He studied medicine at Strassburg and Freiburg, took his doctorate at Bonn in 1900, and landed at Eppendorf Hospital as assistant to Eugen Fraenkel. There, at 26, he wrote the autopsy paper that gave him his eponym:
Mönckeberg JG. “Über die reine Mediaverkalkung der Extremitätenarterien und ihr Verhalten zur Arteriosklerose.” Virchows Arch Pathol Anat Physiol Klin Med 1903;171:141–167.
The same year, he became first assistant to Carl Weigert in Frankfurt — the Weigert of the elastic stain, and a cousin of Paul Ehrlich. Mönckeberg died in Bonn in 1925 at age 47. The paper outlived him by a long way.
What he saw, and what we shrugged at
His claim in 1903 was almost mischievous: there is a calcification of the extremity arteries that is not atherosclerosis. It lives in the tunica media. It is “pure.” It does not narrow the lumen. Pathologists for the next eighty years filed it under “incidental, probably benign, age-related dystrophy.” Much of the standard literature still hedges on its clinical significance.
That is a remarkably long shrug for a finding that turns out to be one of the strongest predictors of amputation we have on a plain foot film.
Edmonds, Watkins, Boulton, Cavanagh: the neuropathy signal
Before the molecular biology arrived, two clinical groups built the case that MAC was pathologically meaningful — and that the link was neuropathy, not atherosclerosis. From King’s College in 1982:
Edmonds ME, Morrison N, Laws JW, Watkins PJ. “Medial arterial calcification and diabetic neuropathy.” BMJ 1982;284:928–930.
X-rays of the feet, knees, and hands of 20 diabetics with severe neuropathy versus 20 age- and duration-matched diabetics with no neuropathy and no clinical PAD. MAC was much more common and much more extensive in the neuropathic group: 15 versus 4 in the feet, 8 versus 0 in the hands. Edmonds and Watkins proposed sympathetic denervation of the medial smooth muscle as the cause. The autonomic nervous system is what holds the artery’s tone; lose that, and the artery loses the plot.
Eleven years later, Manchester extended the work to the foot specifically:
Young MJ, Adams JE, Anderson GF, Boulton AJ, Cavanagh PR. “Medial arterial calcification in the feet of diabetic patients and matched non-diabetic control subjects.” Diabetologia 1993;36:615–621. doi:10.1007/BF00404070.
Four groups: neuropathic diabetics with prior foot ulcer, neuropathic diabetics without ulcer history, non-neuropathic diabetics, and non-diabetic controls. Pedal MAC tracked with neuropathy and with prior ulceration, not with the simple presence or absence of diabetes. The signal wasn’t the sugar; it was the denervation.
Read backward from where we are now, this is what Edmonds, Watkins, Boulton, and Cavanagh were really telling us: the MAC seen on the foot film of a diabetic neuropathic patient is, in some sense, the radiographic signature of a denervated artery. The molecular biologists would later put names on the machinery (RANKL/OPG, BMP-2, matrix Gla protein, Klotho/FGF23), but the clinical phenotype was already there in 1982 and on the foot specifically by 1993.
The molecular rehabilitation
The reframing kept building. Lehto, Niskanen, and colleagues in 1996 published the first big cohort signal in type 2 diabetes, showing that medial calcification was a neglected harbinger of cardiovascular complications. Through the 2000s the molecular biology rewrote the lesion entirely. Medial calcification is not passive dystrophy. Vascular smooth muscle cells transdifferentiate into an osteogenic phenotype and deposit hydroxyapatite between the intimal and adventitial layers, recruiting the same RANKL/OPG, BMP-2, matrix Gla protein, and Klotho/FGF23 machinery the skeleton uses. The artery is, in effect, trying to become bone. Mönckeberg saw the radiograph; Edmonds and Boulton-Cavanagh saw the neuropathy correlate; we now see the genome.
Ferraresi: BAD transmission, SAD distribution
The conceptual move that really reframes the field for limb preservation came from Roberto Ferraresi and his Milan group:
Ferraresi R, Mauri G, Losurdo F, et al. “BAD transmission and SAD distribution: a new scenario for critical limb ischemia.” J Cardiovasc Surg (Torino) 2018;59:655–664.
They proposed two diseases that overlap at the foot: BAD (Big Artery Disease — the classical atherosclerotic transmission line from iliac to dorsalis pedis) and SAD (Small Artery Disease — the obstructive process below the ankle in the plantar arch, metatarsal, and digital arteries). BAD is a transmission failure. SAD is a distribution failure. CLTI patients have either, or both. They followed it with a scoring system:
Ferraresi R, Ucci A, Pizzuto A, et al. “A novel scoring system for small artery disease and medial arterial calcification is strongly associated with major adverse limb events in patients with chronic limb-threatening ischemia.” J Endovasc Ther 2021;28:194–207. doi:10.1177/1526602820966309.
Their finding — that SAD and MAC scores are powerful, independent prognosticators of major adverse limb events, and that SAD and MAC are best understood as expressions of the same obstructing disease — is the bridge from Mönckeberg’s autopsy slide to today’s foot film.
UCSF puts it on a 0–5 scale you can grade between cases
Iris Liu, Bian Wu, Roberto Ferraresi, Alex Reyzelman, Jade Hiramoto, Peter Schneider, Mike Conte, and Shant Vartanian at UCSF (with Ferraresi as a co-author) operationalized the MAC score against hard endpoints in CLTI:
Liu IH, Wu B, Krepkiy V, Ferraresi R, Reyzelman AM, Hiramoto JS, Schneider PA, Conte MS, Vartanian SM. “Pedal arterial calcification score is associated with the risk of major amputation in chronic limb-threatening ischemia.” J Vasc Surg 2022;75:270–278.e3. doi:10.1016/j.jvs.2021.07.235.
Liu IH, Wu B, Krepkiy V, El Khoury R, Ferraresi R, Reyzelman AM, Hiramoto JS, Schneider PA, Conte MS, Vartanian SM. “Pedal arterial calcification score is associated with hemodynamic change and major amputation after infrainguinal revascularization for chronic limb-threatening ischemia.” J Vasc Surg 2022;76:1688–1697.e2. doi:10.1016/j.jvs.2022.07.009.
One point each for ≥2 cm of continuous calcification in the dorsalis pedis, lateral plantar, and first metatarsal arteries, and ≥1 cm in the hallux and non-hallux digital arteries. Total 0–5. Highly reproducible. Predicts amputation. Predicts unresolved distal ischemia after revascularization. A grading system most of us can apply at the lightbox in a minute.
USC and UNC validate it across institutions
Our combined USC–UNC team led by Kate McGinigle and Alex DiBartolomeo took the next step — multi-institutional validation:
DiBartolomeo AD, Browder SE, Bazikian S, Thapa D, Kim S, Yohann A, Armstrong DG, McGinigle KL. “Medial arterial calcification score is associated with increased risk of major limb amputation.” J Vasc Surg 2024;79:127–134. doi:10.1016/j.jvs.2023.07.108.
The pedal MAC score, when combined with WIfI staging, is reproducible and generalizable as a measure of inframalleolar disease and predicts major limb amputation in CLTI. The marriage with WIfI matters: it puts a vascular biomarker derived from a cheap plain film into the wound–ischemia–infection framework already in our workflow.
The international signal keeps accumulating
From West China Hospital, a 979-patient prospective cohort:
Chen L, Chen D, Gong H, Wang C, Gao Y, Li Y, Tang W, Zha P, Ran X. “Pedal medial arterial calcification in diabetic foot ulcers: A significant risk factor of amputation and mortality.” J Diabetes 2024;16:e13527. doi:10.1111/1753-0407.13527.
From the Georgetown plastic-surgery limb salvage group (Attinger, Evans, Akbari, Rohrich), a decade of complex reconstructive experience graded with the Ferraresi score:
Rohrich RN, Li KR, Episalla NC, Atkinson K, Lin RP, Ferdousian S, Youn RC, Evans KK, Akbari CM, Attinger CE. “Understanding the prevalence of medial arterial calcification among complex reconstructive patients: insights from a decade of experience at a tertiary limb salvage center.” J Clin Med 2025;14:596. doi:10.3390/jcm14020596.
And from Suludere, Lavery and colleagues, a study tying MAC back to the foot infection world:
Suludere MA, Ozer Balin S, Lavery LA, et al. “Mönckeberg’s medial calcific sclerosis in diabetic and non-diabetic foot infections.” Wound Repair Regen 2023;31:475–481. doi:10.1111/wrr.13101.
The plain foot film is now a cardiovascular risk-stratification tool. That is a long way from “incidental finding.”
Why it matters at the bedside
Several clinical consequences cascade out of the SAD-with-MAC framing.
The ABI is silently broken in these patients. Non-compressible vessels give a “normal” or supranormal index over a foot that is dying. TBI, TcPO₂, and skin perfusion pressure are the workarounds. Plain foot films, once read for fractures and Charcot, are now read for arterial fate.
The angiosome debate looks different through a SAD lens. Revascularizing a patent dorsalis pedis when the plantar arch is calcified into stone is BAD-fixing in a SAD-failing limb.
“No-option” CLTI exists as a category in part because endovascular tools were built for transmission failure, not distribution failure. This is why regenerative and metabolic strategies — autologous peripheral blood mononuclear cell implantation in SAD, HGF gene therapy, edetate disodium chelation in the TACT and TACT2 line, and a growing list of pharmacotherapies — converge on SAD-with-MAC as the population most desperate for something other than a wire.
The connection in one paragraph
Mönckeberg in 1903 described, with autopsy and a hand lens, the exact lesion that in 2026 is such a strong plain-film predictor of pathology. The eponym sat dormant for almost eighty years because it did not fit the atherosclerosis paradigm — it was the wrong character in the wrong play. Then Edmonds and Watkins at King’s tied it to neuropathy, Boulton and Cavanagh at Manchester pinned it on the foot, the molecular biologists turned the artery into bone, the Italians turned the foot into two diseases, and a network of vascular surgeons, podiatric surgeons, and plastic surgeons across Manchester, Milan, San Francisco, Los Angeles, Chapel Hill, Chengdu, and Washington DC turned a curious 1903 finding into a clinical decision tool.
Not bad for a Hamburg senator’s son who didn’t make 50.
#DiabeticFoot #ActAgainstAmputation #PAD #CLTI #MedialArterialCalcification #MAC #pMAC #LimbPreservation #VascularSurgery #DiabeticFootUlcer #Mönckeberg #SAD #BAD #Ferraresi #Boulton #Cavanagh @ALPSlimb @USC @USC_vascular @KeckSchool_USC @VascularSVS @APMA
