Non-rotator cuff calcific tendinopathy: ultrasonographic diagnosis and treatment

Abstract

Calcific tendinopathy is a condition that is related to the deposition of calcium, mostly hydroxyapatite crystals, within the tendons. The shoulder and the hip are commonly affected joints, but calcific tendinopathy may occur in any tendon of the body. While there is an extensive literature on the ultrasound diagnosis of calcific tendinopathy of the shoulder, there are only sporadic reports on other sites. This review combines the experience of our centers and a thorough analysis of the literature from the last 45 years (1972–2017) in order to highlight the localizations beyond the rotator cuff, their ultrasound characteristics and therapeutic possibilities.

Introduction

Calcific tendinopathy is a common condition related to deposition of calcium, mostly hydroxyapatite crystals, within the tendons. More rarely the pathology can affect also other anatomical structures as the ligaments. The condition is unique and distinct from degenerative tendons disease, and indeed calcium deposition in degenerative tendinopathy has a different chemical composition than in calcific tendinitis. The shoulder and the hip are the most commonly affected joints [1], but calcific tendinitis may occur in any tendons of the body [2, 3]. In many cases asymptomatic, it can sometimes be a cause of severe pain. The pathogenesis is not completely understood, but it seems related to areas of hypoxia in tendons, which lead to fibrocartilaginous metaplasia, followed by the formation of a calcium deposit, typically in healthy tendons with no pathologic findings.

Calcific tendinopathy is a dynamic process that evolves through successive stages, characterized by distinct imaging, pathologic and clinical features. Four stages of disease are described in the Uhthoff Cycle [4]: pre-calcific, in which fibrocartilaginous transformation occurs within tendon fibers, usually asymptomatic (Stage 1); formative, in which calcifications are formed, usually poorly symptomatic and including sub-acute low-grade pain, increasing at night (Stage 2); resorptive, in which the tendon develops increased vasculature and calcium deposits are usually removed by phagocytes, but calcifications may migrate into the adjacent structures (Stage 3); and post-calcific, in which there is self-healing and repair of the tendon fibers over several months, which may be associated with pain and restricted function (Stage 4).

While there is an extensive literature on the ultrasound diagnosis of the calcific tendinopathy of the shoulder and its therapies [5–10], there are only sporadic reports on the other sites. This article aims to provide a systematic review of the literature to highlight the localizations of calcific tendinopathy beyond the rotator cuff, its ultrasound characteristics and the therapeutic possibilities.

This review is generated from the combined experience of our centers, as indicated by the references in the text, and a thorough analysis of the literature from the last 45 years (1972–2017). A systematic search of the literature was performed in PubMed and included original studies and review articles. Case reports and case series were selected according to clinical relevance. Of the 192 selected articles on PubMed animal and cadaver studies were excluded (8 articles), so 184 articles were evaluated (Tables 1, 2, 3).

Table 1.

Articles reporting neck calcific tendinopathy

Article type	Author	Site	Muscle	N°	Age	Sex	Year
Case report	Abdelbaki A. et al. [11]	Neck	Longus colli (C1–C2)	2	38	M	2017
					53	F
Case report	Ahmed O. H. et al. [12]	Neck	Longus colli	2			2012
Case report	Alamoudi U. et al. [13]	Neck	Longus colli (C1–C2)	1	53	M	2017
Case report	Andrade C. S. et al. [14]	Neck	Longus colli (C1–C2)	1	54	M	2015
Case report	Bailey C. W. et al. [15]	Neck	Longus colli	1			2015
Case report	Benanti J. C. et al. [16]	Neck	Longus colli (C1–C2)	5	27–32–33–54	M	1986
					41	F
Case report	Bladt O. et al. [17]	Neck	Longus colli (C1–C2)	1			2008
Case report	Blome S. A. et al. [18]	Neck	Longus colli (C1–C2)	1	57	F	1987
Case report	Boikov A. S. et al. [19]	Neck	Longus colli (C4–C5)	1	68	M	2012
Case report	Borrmann A. et al. [20]	Neck	Longus colli (C1–C2)	2	41–43	F	2008
Case report	Chen C-H. et al. [21]	Neck	Longus colli (C1–C2)	1	47	M	2015
Case report	Chung T. et al. [22]	Neck	Longus colli (C1–C2)	1	36	F	2005
Case report	Colella D. M. et al. [23]	Neck	Longus colli (C1–C2)	1	44	F	2016
Case report	Coulier B. et al. [24]	Neck	Longus colli (C1–C2)	1	63	F	2011
Case report	De Maeseneer M. et al. [25]	Neck	Longus colli	1			1997
Case report	De Temmerman G. et al. [26]	Neck	Longus colli	1			2007
Case report	Desmots F. et al. [27]	Neck	Longus colli (C1–C2)	1	43	M	2013
Case report	Eastwood J. D. et al. [28]	Neck	Longus colli (C1–C2)	3	40	M	1998
					31–50	F
Case report	Ellika S. K. et al. [29]	Neck	Longus colli (C1–C2)	2	35	M	2008
					41	F
Case report	Estimable K. et al. [30]	Neck	Longus colli (C1–C2)	1	45	M	2015
Retrospective study	Fahlgren H. [31]	Neck	Longus colli (C1–C2)	28	Mean 51.5 (range 26–81)	14 M	1986
						14 F
	Figler T. [32]	Neck	Longus colli	1			1993
Case report	Gabra N. et al. [33]	Neck	Longus colli (C1–C2)	4	52–63	M	2013
					36–40	F
Case report	Hall F. M. et al. [34]	Neck	Longus colli (C1–C2)	1	50	F	1986
Case report	Haun C. L. et al. [35]	Neck	Longus colli (C1–C2)	4	57	M	1978
					32–37–53	F
Case report	Horowitz G. et al. [36]	Neck	Longus colli (C1–C2)	8	36.6 + − 5.2 (range 26–44)	3 M	2013
						5 F
Case report	Jimenez S. et al. [37]	Neck	Longus colli (C1–C2)	1	58	M	2007
Case report	Joshi G. S. et al. [38]	Neck	Longus colli (C1–C2)	1	46	M	2016
Case report	Kanzaria H. et al. [39]	Neck	Longus colli (C1–C2)	1	48	F	2011
Case report	Kaplan M. J. et al. [40]	Neck	Longus colli (C1–C2)	5	38	M	1984
					22–28–32–46	F
Case report	Karasick D. et al. [41]	Neck	Longus colli (C1–C2)	1	49	M	1981
Case report	Kenzaka T. et al. [42]	Neck	Longus colli (C1–C2)	1	47	M	2017
Case report	Khurana B. et al. [43]	Neck	Longus colli (C1–C2)	1	49	F	2012
Case report	Kim Y-J. et al. [44]	Neck	Longus colli (C1–C2)	8	42–43–46–48–49	M	2017
					41–42–45	F
Case report	Kupferman T. A. et al. [45]	Neck	Longus colli (C1–C2)	1	34	M	2007
Case report	Kusunoki T. et al. [46]	Neck	Longus colli (C1–C2)	1	34	F	2006
Case report	Lee S. et al. [47]	Neck	Longus colli (C4–C5)	1	30	F	2011
Case report	Leep Hunderfund A. N. et al. [48]	Neck	Longus colli (C1–C2)	1	36	F	2008
Case report	Mannoji C. et al. [49]	Neck	Longus colli (C1–C2)	1	45	F	2015
Case report	Martindale J. L. et al. [50]	Neck	Longus colli (C1–C2)	1	58	M	2012
Case report	Mihmanli I. et al. [51]	Neck	Longus colli	1			2001
Case report	Naqshabandi A. M. et al. [52]	Neck	Longus colli (C1–C2)	1	45	M	2011
Case report	Newmark H. et al. [53]	Neck	Longus colli (C1–C2)	4	21–39–44–49	M	1978
Case report	Newmark H. et al. [54]	Neck	Longus colli (C1–C2)	1	62–66	M	1981
					50	F
Case report	Newmark H. et al. [55]	Neck	Longus colli (C1–C2)	1	32	F	1986
Case report	Nozu T. et al. [56]	Neck	Longus colli (C1–C2)	1	42	F	2015
Case report	Nunes C. et al. [57]	Neck	Longus colli (C1–C2)	1	48	F	2012
Case report	Offiah C. E. et al. [58]	Neck	Longus colli (C1–C2)	3	51	M	2009
					37–66	F
Case report	Oh J. Y. et al. [59]	Neck	Longus colli (C1–C2)	1	25	M	2016
Case report	Omezzine S. J. et al. [60]	Neck	Longus colli (C1–C2)	1	60	M	2008
Case report	Park R. et al. [61]	Neck	Longus colli (C1–C2)	1	30	F	2010
Case report	Park S. Y. et al. [62]	Neck	Longus colli (C5–C6)	1	41	F	2010
Case report	Pellicer Garcia V. et al. [63]	Neck	Longus colli (C1–C2)	1	48	F	2012
Case report	Queinnec S. et al. [64]	Neck	Longus colli (C1–C2)	1	56	M	2011
Case report	Razon R. V. B. et al. [65]	Neck	Longus colli (C1–C2)	1	43	M	2009
					30	F
Case report	Sanghvi D. A. et al. [66]	Neck	Longus colli	1			2006
Case report	Sarkozi J. et al. [67]	Neck	Longus colli (C1–C2)	1	42	M	1984
Case report	Shibuki T. et al. [68]	Neck	Longus colli (C1–C2)	1	74	F	2017
Case report	Shin D-E. et al. [69]	Neck	Longus colli (C1–C2)	2	51	M	2010
					22	F
Retrospective study	Silva C. F. et al. [70]	Neck	Longus colli (C1–C2)	9	Mean age 44 + − 6.9	5 M	2014
						4 F
Case report	Siwiec R. M. et al. [71]	Neck	Longus colli (C1–C2)	1	37	F	2009
Case report	Sokolov M. et al. [72]	Neck	Longus colli (C1–C2)	1	28	F	2009
Case report	Sierra Solis A. et al. [73]	Neck	Longus colli (C1–C2)	1	49	F	2017
Case report	Southwell K. et al. [74]	Neck	Longus colli (C1–C2)	1	56	M	2008
Case report	Suyama Y. et al. [75]	Neck	Longus colli (C1–C2)	1	32	M	2015
Case report	Szelei N. et al. [76]	Neck	Longus colli	2			2001
Case report	Tagashira Y. et al. [77]	Neck	Longus colli (C1–C2)	1	40	M	2015
Case report	Tamm A. et al. [78]	Neck	Longus colli (C1–C2)	1	41	F	2015
Case report	Tezuka F. et al. [79]	Neck	Longus colli (C1–C2)	1	59	F	2014
Case report	Torbati S. S. et al. [80]	Neck	Longus colli	1			2014
Case report	Uchiyama D. et al. [81]	Neck	Longus colli (C1–C2)	1	47	F	2016
Case report	Ulusoy O. L. et al. [82]	Neck	Longus colli (C1–C2)	1	35	F	2016
Case report	Van Kerkhove F. et al. [83]	Neck	Longus colli (C1–C2)	1	65	F	2007
Case report	Wakabayashi Y. et al. [84]	Neck	Longus colli (C1–C2)	1	74	F	2012
Case report	Widius D. M. [85]	Neck	Longus colli (C1–C2)	2	40	M	1985
					21	F
Case report	Wolzak H. et al. [86]	Neck	Longus colli (C1–C2)	1	66	F	2010
Case report	Yaylaci S. et al. [87]	Neck	Longus colli (C1–C2)	2	42	M	2015
					47	F
Case report	Zapolsky N. et al. [88]	Neck	Longus colli (C1–C2)	1	52	M	2017
Case report	Zibis A. H. et al. [89]	Neck	Longus colli (C1–C2)	1	36	F	2013

Table 2.

Articles reporting upper extremities calcific tendinopathy

Article type	Author	Site	Muscle	N°	Age	Sex	Year
Case report	Abate et al [90]	Elbow	Common extensor		34	F	2016
Case report	Ali S. N. et al. [91]	Hand	Flexor digitorum superficialis of III finger		66	M	2004
Case report	Cahir J. et al. [92]	Arm	Pectoralis major		40	M	2005
Case report	Dilley D. F. et al. [93]	Hand	Abductor pollicis longus	3	28–32–62	F	1991
			Flexor carpi radialis
			Flexor carpi ulnaris
			Abductor pollicis brevis
Case report	Durr H. R. et al. [94]	Arm	Pectoralis major		31	F	1997
Case report	El-Essawy M. T. et al. [95]	Arm	Pectoralis major		64	M	2012
Case report	Galliani I. et al. [96]	Elbow	Common extensor		25	F	1998
Case report	Garayoa S. A. et al. [97]	Elbow	Biceps (distal)		61	F	2010
Review	Goldman A. B. [98]	Shoulder	Biceps (long head)	19			1989
Case report	Gossner J. [99]	Elbow	Biceps (distal)		89	F	2018
Case report	Greene T. L. et al. [100]	Hand	Intrinsic (II–III metacarpal head)	2	24	F	1980
			Intrinsic (III–IV metacarpal head)		36	M
Case report	Hakozaki M. et al. [101]	Hand	Extensor pollicis longus		10	M	2007
Case report	Hansen U. et al. [111]	Hand	Flexor digitorum superficialis		8	M	2007
Case report	Harris A. R. et all [102]	Wrist	Flexor within carpal tunnel		45	F	2009
Case report	Hayes C. W. et al. [1]	Hip	Gluteus maximus	2		2 M	1990
			Adductor magnus	1	Mean 51 (range  39–62)
		Chest	Pectoralis major	2		3F
Case report	Huntley J. S. et al. [103]	Hand	Flexor index		42	F	2003
Case report	Ikegawa S. [104]	Arm	Pectoralis major	2	61	M	1996
					65	F
Case report	Kheterpal A. et al. [105]	Wrist	Flexor pollicis longus		8	M	2014
Case report	Kim J. H. et al. [106]	Hand	Distal interphalangeal joint (IV finger)		72	F	2016
Case report	Kim K. C. et al. [107]	Shoulder	Biceps (long head)		41	M	2007
Case report	Lee H. O. et al. [108]	Foot	Flexor hallucis brevis	4	32–42	F	2012
		Hand	Abductor digiti minimi		34–61	M
			Abductor pollicis brevis
Case report	Munjal A. et al. [109]	Hand	Flexor digitorum profundus		51	F	2013
Case report	Murase T. et al. [110]	Elbow	Biceps (distal)		67	F	1994
Case report	Nofsinger C. C. et al. [111]	Shoulder	Trapezius		43	F	1999
Case report	Park J-Y. et al. [112]	Elbow	Biceps (distal)		52	F	2008
Case report	Ryan W. G. [113]	Wrist	Flexor carpi ulnaris		47	F	1993
Case report	Sakamoto K. et al. [114]	Elbow	Biceps (distal)		3	M	2002
Case report	Saleh W. R. et al. [115]	Wrist	Flexor within carpal tunnel		94	F	2008
Case report	Schneider D. et al. [116]	Hand	First and second dorsal interosseous of the hand		68	F	2017
Case report	Seiler J. G. et al. [117]	Wrist	Flexor digitorum profundus		11	M	1995
Case report	Selby C. [118]	Hand	First interphalangeal joint (pollicis)		57	F	1984
Case report	Shields J. S. et al. [119]	Hand	Abductor pollicis brevis	2	20	M	2007
					20	F
Case report	Torbati S. S. et al. [120]	Wrist	Flexor carpi ulnaris		27	M	2013
Case report	Walocko F. M. et al. [121]	Hand	Flexor index		9	M	2017
Case report	Yasen S. [122]	Wrist	Flexor carpi ulnaris		64	F	2012

Table 3.

Articles reporting lower extremities calcific tendinopathy

Article type	Author	Site	Muscle	N°	Age	Sex	Year
Case report	Abram S. G. F. et al. [123]	Knee	Quadriceps		43	M	2012
Case report	Almedghio S. et al. [124]	Hip	Gluteus medius	2	37	M	2014
					51	F
Cross-sectional study	Beebe J. A. et al. [125]	Knee	Patellar				2013
Case report	Berney J. W. [126]	Hip	Gluteus maximus		62	M	1972
Case report	Braun-Moscovici Y. et al. [127]	Hip	Rectus femoris (proximal)	3	51–60	M	2006
					45	F
Case report	Choudur H. N. et al. [128]	Hip	Gluteus maximus	4	46–60–68	F	2006
					46	M
Case report	Cox D. et al. [129]	Foot	Peroneus longus		50	F	1991
Longitudinal study	Craig T. Gillis et al. [130]	Foot	Achilles	14			2016
Case report	Doucet C. et al. [131]	Leg	Popliteus		48	F	2017
Case report	Duncan Tennent T. et al. [132]	Leg	Popliteus		47	M	2003
Case report	Durst H. B. et al. [133]	Hip	Gluteus maximus		50	M	2006
Case report	Ferraro A. et al. [134]	Hip	Gluteus maximus	4			1995
Case report	Garner H. W. et al. [135]	Foot	Flexor hallucis brevis		40	F	2013
Case report	Harries L. et al. [136]	Foot	Tibialis posterior		42	F	2011
Case report	Hayes C. W. et al. [1]	Hip	Gluteus maximus	2	Mean 51 (range  39–62)	2 M	1990
			Adductor magnus	1
		Chest	Pectoralis major	2		3 F
Case report	Hottat N. et al. [137]	Hip	Gluteus maximus	2	48–50	F	1999
Longitudinal study	Howell M. A. et al. [138]	Foot	Achilles	40			2016
Case report	Huang K. et al. [139]	Hip	Gluteus maximus		53	F	2017
Case report	Jo H. et al. [140]	Hip	Gluteus medius		56	F	2016
Longitudinal study	Johnson K.W. et all [141]	Foot	Achilles	25	Mean 48 (range  17–75)	10 M + 15 F	2006
Case report	Kandemir U. et al. [142]	Hip	Gluteus medius and minimus		63	F	2003
Case report	Karakida O. et al. [143]	Hip	Gluteus maximus	4			1995
Case report	Kim Y. S. et al. [144]	Hip	Rectus femoris (proximal)		37	M	2013
Case report	Klammer G. et al. [145]	Foot	Peroneus longus		22	F	2011
Case report	Kobayashi H. et al. [146]	Hip	Rectus femoris (proximal)	2	38 and 40	F	2015
Longitudinal study	Kristian Jarl Johan Johansson et al. [147]	Foot	Achilles	34	Mean 42 (range 23–68)	26 M + 8 F	2013
Case report	Kurtoğlu S. et al. [148]	Foot	Achilles		16	M	2015
Case report	Lee H. O. et al. [108]	Foot	Flexor hallucis brevis	4	32–42	F	2012
		Hand	Abductor digiti minimi		34–61	M
			Abductor pollicis brevis
Case report	Lesavre A. et al. [149]	Hip	Gluteus maximus		46	M	2006
Case report	Lim C. H. et al. [150]	Hip	Gluteus maximus		48	F	2017
Case report	Lin T. C. et al. [151]	Foot	Achilles		49	F	2012
Longitudinal study	Maffulli N.et al. [152]	Foot	Achilles	21	Mean 46.9 ± 6.4	15 M + 6 F	2004
Longitudinal study	Miao X.D. et al. [153]	Foot	Achilles	34	Mean 25.2 ± 10.9 (range  24–62)	24 M + 10 F	2016
Case report	Mizutani H. et al. [154]	Hip	Gluteus maximus	1			1994
Case report	Moon S. G. et al. [155]	Pelvis	Ischiococcygeus		35	M	2012
Case report	Mouzopoulos G. et al. [156]	Foot	Peroneus longus		32	M	2009
Retrospective study	Paik N. C. et al. [157]	Hip	Gluteus medius	6	54–62	2 M	2014
					35–33−54–62	4F
Cases series	Park S-M [158]	Hip	Gluteus medius	15	Mean 51.5 (range 28–78)	7 M	2014
			Rectus femoris	10
			Iliopsoas	1		22 F
			Piriformis	1
			Capsule	3
Case report	Peng X. et al. [159]	Hip	Rectus femoris (proximal)	3	45–38–55	F	2013
Case report	Pierannunzi L. et al. [160]	Hip	Rectus femoris (proximal)		43	F	2010
Case report	Pope T.L. Jr. et al. [161]	Hip	Rectus femoris (proximal)	2	37	F	1992
					38	N.A.
Case report	Ramon F.A. et al. [162]	Thigh	Vastus lateralis	3	66	M	1991
					45	M
					45	M
Case report	Rhodes R. A. et al. [163]	Foot	Flexors of the forefoot		33	F	1986
Case report	Rozenbaum M. et al. [164]	Hip	Rectus femoris (proximal)	3	30–46–31	F	2008
Case report	Sakai T. et al. [165]	Hip	Gluteus medius		69	M	2004
Case report	Sarkar J.S. et al [166]	Hip	Rectus femoris (proximal)	6	43—30–36–45	F	1996
					49–41
Case report	Shenoy P.M. et al [167]	Leg	Popliteus		45	M	2009
Case report	Singh J.R. et al [168]	Hip	Gluteus Maximus		47	M	2015
Case report	Stark P. et al [169]	Hip	Piriform				1983
Case report	Tamangani J. et al [170]	Hip	Adductor brevis		52	F	2009
Case report	Thomason H.C. et al [171]	Hip	Gluteus Maximus				2001
Case report	Thornton M. J. et al [172]	Hip	Gluteus Maximus	3	40	M	1998
					47–63	F
Case report	Tibrewal S.B. et al [173]	Leg	Popliteus	3	Mean 35,2 (range 27–49)	1M+2F	2002
Case report	Tomlinson M. P. et al [174]	Foot	Exstensor Hallucis Longus		47	F	2006
Case report	Trujeque L. et al [175]	Knee	Quadriceps		59	M	1977
Case report	Van Damme K. et al [176]	Hip	Gluteus Maximus	2	52–73	M	2017
					75–75–75	F
Case report	Varghese B. et al [177]	Knee	Quadriceps		46	M	2006
Longitudinal study	Watanabe H. et al [178]	Hip	Rectus Femoris (Proximal)	6	N.A.	N.A.	1998
Case report	Wepfer J. F. et al [179]	Hip	Gluteus Maximus	7			1983
Case report	Williams A. A. et al [180]	Hip	Gluteus Maximus		32	M	2016
Case report	Yang I. et al [181]	Hip	Gluteus Medius		56	F	2002
Case report	Yang J-H. et al [182]	Hip	Rectus Femoris (Proximal)		50	F	2013
Longitudinal study	Yi S. R. et al [183]	Hip	Gluteus Medius	15	Mean age 51 (range 32–74)	21 M	2015
			Rectus Femoris	6		7 F
			Adductor	4
			Vastus Lateralis	2
			Sartorius	1
Case report	Yun H.H. et al [184]	Hip	Rectus Femoris (Proximal)	6	Mean 41 (range 33–49)	5F + 1M	2009
Case report	Zajonz D. et al [185]	Hip	Ileopsoas	41	41	F	2013
Case report	Zini R. et al [186]	Hip	Rectus Femoris (Proximal)	6	Mean 32,6	F	2014

Neck

The neck, despite being a rare site of calcific tendinopathy, is the most frequently reported site in the literature, with 157 patients in 79 different articles. Calcific deposits tend to occur anteriorly to C1 and C2, near the insertion of the longus colli muscle, in two cases anteriorly to C4–C5 and, only in one, to C5–C6. Calcific tendinopathy may manifest with cervical and shoulder pain [75], neck stiffness, dysphagia or odynophagia, sore throat, fever and mild leukocytosis. Clinical findings of calcific retropharyngeal tendonitis are similar to the retropharyngeal abscess that represents a medical emergency [46]. Other conditions, like meningitis, pharyngitis, epiglottitis, infectious spondylitis, traumatic injury, cervical disk herniation, muscle spasm, foreign body aspiration and neoplasm, must be excluded [23, 39].

Standard latero-lateral radiographs of the cervical spine, showing calcification at the insertion of the longus colli muscle, are usually adequate for a diagnosis. Computed tomography may be useful for a differential diagnosis with retropharyngeal abscess. Magnetic resonance imaging can identify prevertebral edema [77]. There are no descriptions of ultrasound evaluations of calcific tendinopathy of the neck muscles, most likely because they are rarely examined using ultrasound.

Shoulder and arm

The shoulder is the joint most commonly affected by calcific tendinopathy, mostly the rotator cuff tendons [3, 10, 187], rarely the other tendons (pectoralis major, trapezius, biceps brachii) (Fig. 1). Pectoralis major calcific tendinopathy was described in four articles. Radiographs all showed a lithic area of the lateral humeral cortex with periosteal reaction. Second-level examinations (computed tomography and magnetic resonance imaging) and, in one case biopsy, were necessary for the aspecific findings of the radiographs. A single case of calcific tendinopathy is reported in the trapezius tendon. Biceps brachii calcific tendinopathy has been reported in both the proximal and the distal insertions (Fig. 2), except of the brief head. Calcific tendinopathy was also reported concomitant in the biceps tendon and in the rotator cuff tendon [98]. One of the five cases of calcific distal biceps tendinitis affected a 3-year-old boy [114]. Physical examination shows pain, tenderness, swelling and functional limitation, without a history of traumatic events. The differential diagnoses of extra-articular calcific tendinopathy are with calcific bursitis and loose bodies in the biceps tendon recess and synovial osteochondromatosis [98]. Radiography and ultrasound are sufficient for diagnosis.

Fig. 1.

Long head of the biceps tendon calcific tendinopathy at mid-arm level. a Long axis; b, c short axis. Ultrasonography shows calcifications (a calipers, b arrows) with absence of posterior acoustic shadowing (resorptive phase)

Fig. 2.

Distal biceps tendon calcific tendinopathy at the level of the elbow, proximal to the insertion on the radial tubercle. a Long axis, b short axis. Ultrasonography shows calcifications (arrows) with absence of posterior acoustic shadowing (resorptive phase)

Elbow and forearm

Two cases of calcific tendinopathy of the common extensor tendon of the elbow were described in two young women exhibiting pain, swelling and functional limitation. Radiograph and ultrasound showed soft-fluid calcification near the muscle insertion [90]. To our knowledge, the common flexor tendon has not been reported in the literature as affected.

Hand and wrist

Tendons of the hand and wrist [188, 189] are rarely reported as affected by calcific tendinopathy (incidence of 2%) [116], but more often the flexor tendons than the extensors (flexor carpi ulnaris four cases, flexor digitorum profundus two cases, flexor digitorum superficialis two cases, abductor pollicis brevis 2). Authors have described calcific tendinopathy in the flexor carpi radialis, abductor digiti minimi, extensor pollicis longus, abductor pollicis longus, flexor pollicis longus and the tendons of the intrinsic muscles. Two cases of calcific tendinopathy of the carpal tunnel tendons have been reported in literature, both with carpal tunnel syndrome.

The differential diagnosis includes soft-tissue infection, bone fracture, metabolic disorder (hyperparathyroidism, gout, pseudogout, hypervitaminosis D, hypercalcemia), degenerative or inflammatory or autoimmune conditions. Clinical presentation, ultrasound and radiographs can differentiate calcific tendinopathy from other etiologies [121].

Hip

The hip [190] is the second most common site of calcific tendinopathy, after the shoulder [158]. The tendons of the rectus femoris are the most commonly involved (Fig. 3) described in 56 patients in 14 different articles. Both direct and indirect tendon components may be affected by this pathology, with prevalence, in our experience, of the direct tendon. But it is also necessary to distinguish the tendinous calcifications from calcifications of their insertional bursae, just beneath the direct and indirect tendon, that may occur quite frequently. The second most common group are the gluteal tendons (42 cases of the gluteus medius and 36 cases of the gluteus maximus reported). Adductor magnus, adductor longus and adductor brevis calcific tendinopathy have been described in six cases (1 magnus, 1 brevis and 4 unknown). Other rare sites are the piriformis (2 cases), the iliopsoas (2 cases), the ischiococcygeus (1 case) and the sartorius (1 case).

Fig. 3.

Direct tendon of rectus femoris calcific tendinopathy at the level of the anteroinferior iliac spine. a Long axis, b short axis. Ultrasonography shows calcifications (arrows) with absence of posterior acoustic shadowing (resorptive phase). AIIS anteroinferior iliac spine

Usually occurring in middle-age, patients have functional limitation, tenderness, pain and a positive Patrick’s test [183]. Depending on the affected tendon, the differential diagnosis includes infection [124, 180], arthritis, lumbar radiculopathy [126, 140, 168], os acetabuli, avulsion fracture, insertional calcified bursitis, sesamoid bones, myositis ossificans and chondrosarcoma [146]. Sonography and standard radiographs can be used for diagnosis, showing the calcification. Sometimes computed tomography is useful for bone evaluation, and MRIs to show soft-tissue edema and bone marrow edema.

Thigh, knee and leg

Thigh, knee and leg are rarely affected by calcific tendinopathy, and only a few cases involving the quadriceps tendon, patellar tendon (Fig. 4) and iliotibial band (Fig. 5) [191] are described. In many articles [125, 162] there is no distinction between calcific tendinopathy and calcifications of tendinous tendons, but the majority are calcifications in tendinous tendons. As usual, patients have functional limitations, tenderness and pain. The articles confirm the main role of ultrasound in the diagnosis and in the management of calcific tendinopathy, even of the less common ones.

Fig. 4.

Iliotibial band calcific tendinopathy at the level of the Gerdy’s tubercle. Ultrasonography shows calcifications (arrows) with absence of posterior acoustic shadowing (resorptive phase)

Fig. 5.

Patellar tendon calcific tendinopathy at the level of the tibial tuberosity. Ultrasonography shows calcifications (arrows) with absence of posterior acoustic shadowing (resorptive phase)

Foot and ankle

Calcific tendinopathy of the ankle [192] and foot is frequently misdiagnosed because of its rare occurrence and a clinical presentation that is similar to other entities. Achilles tendon calcific tendinopathy was described in eight articles, in both sexes, but more commonly in males. The second most commonly involved tendons are the peroneus longus (3 cases) and the flexor hallucis brevis (2 cases). Single cases have been described in other tendons (extensor hallucis longus, tibialis posterior and flexor of the forefoot).

Motion restriction secondary to pain, erythema, swelling and tenderness are the most frequent symptoms, in the absence of acute trauma [108]. The differential diagnosis is broad and includes gout or pseudogout, avulsion fractures, sesamoid bones, myositis ossificans and infection [156]. Ultrasonography and radiography can be used to make a diagnosis of calcific tendinopathy of the ankle and the foot, while computed tomography and MRI have few indications [136].

Ligaments

Calcifications of the ligaments, that can produce an important pain symptomatology like the calcific tendinopathy of the rotator cuff, are more frequent in the medial collateral ligament (proximal insertion) of the knee, where they can also become of considerable size [193, 194]. Other ligaments less frequently affected by the pathology are the lateral collateral ligament, the anterior or posterior cruciate ligament of the knee and sometimes Wrisberg ligament [195, 196].

Differential diagnosis

Depending on the affected tendon the differential diagnosis includes many diseases. Among the idiopathic ones the most known is the diffuse idiopathic skeletal hyperostosis (DISH) which predominantly affects the spine while ligaments and tendons of the appendicular skeleton are rarely involved [197]. In these cases, the US differential diagnosis is not possible and is generally related to the distribution and site of the calcifications.

The differential diagnosis with the calcification in a degenerative tendinopathy is more easy even with the ultrasound because the affected tendon appear as normal in calcific tendinopathy while shows diffuse signs of degeneration (e.g., hypoechogenicity, loss of the fibrillar aspect) around the calcification in a degenerative tendinopathy. In the most challenging cases, CT and MRI may be necessary.

Non-surgical treatment (or conservative, or minimally invasive treatments)

Calcific tendinopathy is usually a self-limited condition, so the initial management of pain is conservative, with physical therapy and oral administration of NSAIDs. If these treatments fail, other non-surgical therapeutic options may be considered: extra-corporeal shock wave therapy (ESWT), steroid injection (ultrasound-guided or unguided) and US-guided percutaneous aspiration of calcific tendinopathy (US-PICT). ESWT is based on the application of repetitive pulses over the affected site. The results are variable and the exact underlying mechanism of the therapeutic effect on calcific tendinopathy is still debated. It seems to be related to the phagocytosis of calcium deposition induced by the neovascularization response and leukocyte chemotaxis [198]; ESWT therapy is painful, expensive and not widely available. The use of conservative treatment or ESWT in patients with acute pain from calcific tendinopathy in resorption seems to be suboptimal, and often fails. The symptoms in this phase significantly impact quality of life [9, 199]. Minimally invasive interventional techniques (steroid injection of calcific tendinitis) may be used in these cases (US-guided or unguided) and/or US-guided percutaneous aspiration of calcific tendinopathy (US-PICT) [200]. A study by de Witta et al. reports that US-PICT is a superior method compared to steroid injection in the calcific tendinitis of the rotator cuff [201]. In cases of hard calcifications in mildly symptomatic patients, elective treatments should be considered [202]. Percutaneous treatment is not indicated when patients are asymptomatic, and calcification is very small (≤ 5 mm) [203]. Different approaches have been reported in recent studies and all include the use of a fluid: local anesthetic or saline solution to dissolve calcium deposits; one needle or two needles are used to inject and retrieve the fluid to dissolve calcium deposits. Recent evidence has suggested that a double-needle approach might be more appropriate for treating harder deposits, while one needle may be more useful in treating fluid calcifications. Some advantages of US-PICT are that the procedure does not require any hospitalization, is performed under local anesthesia, the patient can return home about 30 min after the procedure is complete, there is no need for post-procedural immobilization, and the patient can return to work sooner [10].

Surgical treatment

Arthroscopic treatment of calcific tendinitis involves selected cases in which conservative or less invasive approaches have failed. Calcification removal techniques vary according to the type of tendon incision and the instrumentation used to remove the calcium deposit. The surgery allows the removal of calcification and a thorough cleaning of the joint of interest. Surgery requires hospitalization, general anesthesia or sedation, however, and a relatively long rehabilitation period after treatment.

Conclusion

Calcific tendinopathy is commonly found in non-rotator cuff tendons. It is easily diagnosed using ultrasound, although ultrasound is rarely used in some anatomic sites, such as neck muscles. Depending on the affected tendon the differential diagnosis includes many diseases, and CT and MRI may be necessary. Usually occurring in middle-age, it can however affect patients of all ages, and a case was reported in a 3-year-old boy. Patients with calcific tendinopathy have functional limitation, tenderness and pain.

Resorption of deposits generally occurs spontaneously, although some patients show persistent clinical symptoms and require therapy. Various therapies can be used, although ultrasonographic guided therapeutic procedures (steroid injection or percutaneous aspiration) seem to be the most effective, particularly for calcific tendinopathy in resorption. Surgery remains an option in cases where other approaches have failed.

Compliance with ethical standards

Conflict of interest

C.B. is a consultant for Bracco Imaging and Doc. Congress; the other authors have nothing to disclose.

Ethical standards

Exams have been performed in accordance with the ethical standards laid down in the Helsinki Declaration of 1975 and its late amendments. Additional informed consent was obtained from all patients for whom identifying information was not included in this article.