What causes Haglund’s deformity on lateral heel radiographs?
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Answer:
Haglund deformity is enlargement of the posterosuperior calcaneus
at the Achilles tendon insertion, seen as a bony bump on the lateral heel
radiograph. It only matters when the adjacent retrocalcaneal bursa and tendon
are inflamed, which is Haglund syndrome. The bump by itself is common: roughly a
third of healthy adults are positive on the classic radiographic measurements.[1]
Why is it called so?
It is named after Patrick Haglund, the Swedish orthopaedic surgeon who described
posterior heel pain at the Achilles insertion in 1928, a date some sources give as 1927. The eponym
covers the bony prominence only.
The painful combination of prominence, retrocalcaneal bursitis and Achilles tendon thickening was
named Haglund syndrome in the 1982 Radiology paper that also gave the parallel
pitch lines.[2]
Pathophysiology
The prominence narrows the gap between bone and tendon, so each dorsiflexion squeezes the
retrocalcaneal bursa against the calcaneus. Repeated compression gives bursal effusion, then
insertional tendinosis, then tendon calcification and an insertional spur. What
matters at the workstation is that the pain generator is the bursa and the tendon, not the bone: a
prominent posterosuperior calcaneus with normal soft tissues is
incidental.[2,3]
Alternative names: Retrocalcaneal exostosis, posterosuperior calcaneal
prominence, Mulholland deformity. Not the same as pump bump: in Pavlov’s description
that is the convexity of the superficial soft tissues over the insertion, listed separately
from the bursal projection.[2]
Other associated named signs: Haglund syndrome, the Heneghan-Pavlov parallel
pitch lines, insertional calcific
Achilles tendinopathy, and
the plantar calcaneal spur.
Which Haglund measurement separates painful heels from normal ones?
Only the ones based on how far the bump projects. The classic angle measurements, the
Fowler-Philip angle and the parallel pitch lines, are positive in about a third of healthy adults
and show no difference between patients with insertional Achilles tendinopathy and matched
controls. Bump height and the bump-calcaneus ratio do separate the groups.[1,3,4]
| Measurement | Quoted threshold | Does it separate symptomatic from normal? |
|---|---|---|
| Fowler-Philip angle | Above 75 degrees | No. Mean about 64 degrees in 420 healthy adults, with only 1.4% above 74 degrees. Similar between tendinopathy and controls in two case-control series.[1,5,3] |
| Heneghan-Pavlov parallel pitch lines | Bursal projection above the upper line | No. Positive in 35.7% of 420 healthy adults, and positive more often in controls than in patients (60% vs 41.7%).[1,5] |
| X/Y ratio | Tourne cut-off | No. Positive in 31.9% of healthy adults and not correlated with MRI tendon change.[1,6] |
| Calcaneal pitch angle | No agreed cut-off | Inconsistent. An independent risk factor for tendinopathy in one series, no difference in another.[7,3] |
| Angle of BRINK | Normal mean 20 degrees, deformity 25.1 degrees | Reliable but not discriminating. Kappa 0.8, yet no difference between tendinopathy and controls in 224 patients.[8,3] |
| Bump height | 4 mm or more | Yes. Separated operated from healthy heels, and correlated with MRI tendon thickness.[4,6] |
| Bump-calcaneus ratio | 7.5% or more | Yes, with a larger area under the ROC curve than bump height.[4,6] |
Note that “Haglund deformity height” and “bump height” are different
measurements, which is why the literature looks contradictory. Haglund deformity height was 9.6
against 9.0 mm in patients and controls, and a separate series found the deformity angle identical
at 6.0 degrees in both groups. Neither reached significance. Bump height is the one that separates
them.[5,7,4]
Which findings do predict insertional Achilles tendinopathy?
Not the angles. In a 224-patient case-control study a Haglund deformity, a plantar calcaneal
spur and a raised body mass index were independently associated with insertional Achilles
tendinopathy; every angle measured was not.[3]
- Haglund deformity present, called by projection rather than by angle: 65.4% of tendinopathy heels vs 15.4% of controls, adjusted odds ratio 7.86.[3]
- Plantar calcaneal spur: 64.5% vs 18.8%, adjusted odds ratio 3.97, and the spur was longer.[3]
- Intratendinous calcification: the strongest single factor, 67.3% of tendinopathy heels vs 5.5% of controls, odds ratio 55.7 on a wide interval of 11.2 to 275.9, and 73% in an earlier series.[7,5]
- Posterior heel spur (odds ratio 3.65) and a raised calcaneal pitch angle (odds ratio 6.32) were the other independent factors in the same model.[7]
- Achilles thickness above 6.1 mm and an intratendinous degenerative ratio above 48.8% on MRI: the diagnostic cut-offs for insertional tendinopathy.[6]
- Retrocalcaneal bursal fluid: the finding that converts an incidental bump into Haglund syndrome.[2]
Haglund deformity vs Haglund syndrome and its mimics
| Entity | What it is | Where you see it | Usually painful? |
|---|---|---|---|
| Haglund deformity | Bony posterosuperior calcaneal prominence | Lateral heel radiograph | No, often incidental |
| Haglund syndrome | Prominence plus retrocalcaneal bursitis plus Achilles thickening | Radiograph plus MRI or ultrasound | Yes |
| Insertional Achilles tendinopathy | Degeneration at the insertion, often calcific | MRI or ultrasound, calcification on radiograph | Yes |
| Spondyloarthritis enthesitis | Bursal fluid with calcaneal erosion, often bilateral | MRI, erosion on radiograph | Yes |
| Pump bump | Convexity of the superficial soft tissues over the insertion | Soft tissues on the lateral radiograph | Variable |
Does removing the bump change the outcome?
Possibly not. Among 29 patients operated for calcific insertional Achilles tendinopathy, 16 with
the Haglund prominence resected and 13 without, there was no significant difference in AOFAS, visual
analogue or VISA-A scores, and the non-resection group returned to daily activities sooner, 8.2
weeks against 11.3.[9] That is a small retrospective comparison, not a trial, but Kang and
colleagues reached the same suggestion from radiographs alone.[5] The consequence for the
report is to describe the bursa, the tendon thickness and any intratendinous calcification, which is
what the decision rests on, rather than quoting an angle.
Frequently asked questions
What is a normal Fowler-Philip angle?
About 64 degrees. In 420 healthy adults the mean was 64.2 degrees on the right and 63.9 degrees
on the left, and only 1.4% of people exceeded 74 degrees.[1] The classic abnormal threshold
of 75 degrees is therefore crossed by almost nobody, and the angle is similar in painful and normal
heels, so it should not carry a diagnosis on its own.[5,3]
What is the difference between Haglund deformity and Haglund syndrome?
The deformity is the bone. The syndrome is the deformity plus retrocalcaneal bursitis plus
Achilles tendon thickening, with posterior heel pain and soft-tissue swelling.[2] A prominent
calcaneus with a dry bursa and a normal tendon is a deformity only, and 15.4% of people without
heel pain had one.[3]
Is Haglund deformity diagnosed on x-ray or MRI?
The bony prominence is a radiographic diagnosis, best on a weight-bearing lateral heel view,
which also shows tendon calcification and a plantar spur. MRI or ultrasound tells you whether it is
symptomatic, by showing retrocalcaneal bursal fluid, tendon thickening above 6.1 mm and
intratendinous degeneration.[6]
How common is Haglund deformity in people without heel pain?
Common. In 420 healthy adults the parallel pitch lines were positive in 35.7% and the X/Y ratio
in 31.9%.[1] Using a presence or absence call rather than an angle, 15.4% of pain-free
controls had one.[3] Kang and colleagues found a positive parallel pitch sign in 60% of
controls against 41.7% of patients.[5]
References
- Tunc M, Ozsahin E, Polat S, Altun Z, Sonmez EI, Goker P. Prevalence of Haglund deformity in a hospital-based sample in Turkey. Medicine (Baltimore). 2025;104(42):e45127. PMID: 41189170.
- Pavlov H, Heneghan MA, Hersh A, Goldman AB, Vigorita V. The Haglund syndrome: initial and differential diagnosis. Radiology. 1982;144(1):83-8. PMID: 7089270.
- Dadir IH. Haglund deformity and plantar calcaneal spur in insertional Achilles tendinopathy: prevalence, coexistence, and radiographic characteristics. J Foot Ankle Res. 2026;19(4):e70228. PMID: 42850794.
- Tang SC, Tu KC, Liao WJ, Hsu CT, Shih HT, Tung KK, et al. Novel radiographic measurements for operatively treated Haglund’s deformity. Tomography. 2022;8(1):284-292. PMID: 35202188.
- Kang S, Thordarson DB, Charlton TP. Insertional Achilles tendinitis and Haglund’s deformity. Foot Ankle Int. 2012;33(6):487-91. PMID: 22735321.
- Tang SC, Shih HT, Wu YH, Wang SP. Correlations between insertional Achilles tendinopathy and Haglund’s deformity: MRI and radiographic findings. J Orthop Surg Res. 2025;20(1):666. PMID: 40671082.
- Lee W, Giro ME, Crymes C. Association of Haglund deformity size and insertional Achilles tendinopathy. Foot Ankle Int. 2023;44(8):719-726. PMID: 37218117.
- Nischal N, Chandra Lalita K, Iyengar KP, Reilly I, Botchu R. Angle of BRINK, a new way to measure Haglund’s deformity. Skeletal Radiol. 2023;52(2):193-198. PMID: 36044055.
- Ma L, Chang L, Gong Y, Wang Y, Bian X, Hu C, et al. Haglund resection versus Haglund non-resection for calcific insertional Achilles tendinopathy with Haglund deformity: a retrospective study. Foot Ankle Surg. 2024;30(5):432-439. PMID: 38494414.
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