Kirner's deformity

This condition is considered to be a type of isolated brachydactyly.{{Cite journal |last1=Temtamy |first1=Samia A |last2=Aglan |first2=Mona S |date=2008-06-13 |title=Brachydactyly |journal=Orphanet Journal of Rare Diseases |volume=3 |pages=15 |doi=10.1186/1750-1172-3-15 |pmc=2441618 |pmid=18554391 |doi-access=free }}

A.R. Thomas et al. described it as a "dystrophy of the fifth finger".{{Cite journal |last=Thomas |first=A. R. |title=A New Dystrophy of the Fifth Finger |journal=The Lancet |date=1936 |volume=228 |issue=5890 |pages=163–164 |doi=10.1016/S0140-6736(00)81788-2|s2cid=196407714 }}

This difference was first discovered in 1927 by Kirner et al., when he described a 13-year-old girl with the characteristic radial and volar curvature of the fifth finger's distal phalanx bone.{{Cite journal |last=Rasmussen |first=Lars Bjørn |date=1981-01-01 |title=Kirner's Deformity: Juvenile Spontaneous Incurving of the Terminal Phalanx of the Fifth Finger |journal=Acta Orthopaedica Scandinavica |volume=52 |issue=1 |pages=35–37 |doi=10.3109/17453678108991755 |pmid=7211313 }}

This anomaly is characterized by the painless curvature and "bulbing" of the distal end of the little finger.{{Cite web |title=Dystelephalangy - About the Disease - Genetic and Rare Diseases Information Center |url=https://rarediseases.info.nih.gov/diseases/10059/dystelephalangy |access-date=2022-09-01 |website=rarediseases.info.nih.gov |language=en}} The time of onset varies among people, but the two most common ages of onset are birth and adolescence, although there can be cases where one is already born with a Kirner's deformity that worsens as one grows older (progressive).{{Cite web |last=Sargent |first=Michael |title=Kirner deformity {{!}} Radiology Reference Article {{!}} Radiopaedia.org |url=https://radiopaedia.org/articles/kirner-deformity |access-date=2022-09-01 |website=Radiopaedia |language=en-US}}

Rarely, multiple fingers (which may or may not include the little finger) may be affected with Kirner's deformity; this is known as polytopic dystelephalangy, and cases like this typically have a strong genetic link.{{Cite journal |last=Sugiura |first=Y. |date=1989-07-01 |title=Polytopic dystelephalangy of the fingers |journal=Pediatric Radiology |language=en |volume=19 |issue=6 |pages=493–495 |doi=10.1007/BF02387670 |pmid=2771501 |s2cid=26382843 }}

Other isolated congenital deformities of the hand can occur alongside this deformity; one such instance is the family described by Erduran et al., which presented both camptodactyly and Kirner's deformity.{{Cite journal |last1=Erduran |first1=Mehmet |last2=Altinisik |first2=Julide |last3=Meric |first3=Gokhan |last4=Ulusal |first4=Ali Engin |last5=Akseki |first5=Devrim |date=2013 |title=Camptodactyly and Kirner's Deformity in one Family |url=https://www.academia.edu/59948882 |journal=Balıkesır Health Sciences Journal |volume=2 |issue=1 |pages=36–39 |doi=10.5505/bsbd.2013.03522 }}

The following list comprises the radiological findings associated with Kirner's deformity that have been described in medical literature:{{Cite journal |last1=Satake |first1=Hiroshi |last2=Ogino |first2=Toshihiko |last3=Eto |first3=Jun |last4=Maruyama |first4=Masahiro |last5=Watanabe |first5=Tadayoshi |last6=Takagi |first6=Michiaki |date=June 2013 |title=Radiographic features of Kirner's deformity |journal=Congenital Anomalies |volume=53 |issue=2 |pages=78–82 |doi=10.1111/cga.12010 |pmid=23751041|s2cid=5379782 }}{{Cite journal |date=2014-09-30 |title=The pathogenesis of Kirner's deformity: A clinical, radiological and histological study |journal=Journal of Hand Surgery (European Volume) |volume=40 |issue=6 |pages=633–637 |doi=10.1177/1753193414551911 |pmid=25274771 |s2cid=1811920|last1=Fairbank |first1=S. M. |last2=Rozen |first2=W. M. |last3=Coombs |first3=C. J. }}

• Diaphyseal shortening
• Diaphyseal curvature
• Epiphyseal curvature
• Sclerosing of the diaphyses
• Agenesis of the little finger's flexor digitorum superficialis tendon.
• Abnormal cartilage placement of the diaphyses and the flexor tendon
• Radiolucent nidus in the little finger's distal tuft.
• L-shaped physis

This deformity is caused by a widening of the epiphyseal plate of the fifth finger's distal phalange.{{Cite journal |last1=Adeb |first1=Melkamu |last2=Hayashi |first2=Daichi |last3=Kumar |first3=Yogesh |date=2016-10-21 |title=Kirner's deformity of the fifth finger: a case report |journal=BMC Musculoskeletal Disorders |volume=17 |issue=1 |pages=440 |doi=10.1186/s12891-016-1300-8 |pmid=27769216 |pmc=5073483 |doi-access=free }} Another proposed cause involves the abnormal insertion of the flexor digitorum profundus in the volar area of the fifth finger's distal phalange.{{Cite journal |last1=Lee |first1=Jaejoon |last2=Ahn |first2=Joong Kyong |last3=Choi |first3=Sang-Hee |last4=Koh |first4=Eun-Mi |last5=Cha |first5=Hoon-Suk |date=September 2010 |title=MRI findings in Kirner deformity: normal insertion of the flexor digitorum profundus tendon without soft-tissue enhancement |journal=Pediatric Radiology |volume=40 |issue=9 |pages=1572–1575 |doi=10.1007/s00247-010-1628-4 |pmid=20336287|s2cid=29662827 }} It is thought to be an autosomal dominant trait with reduced penetrance.{{Cite journal |last1=Tianxiao |first1=Ma |last2=Wang |first2=Dongyue |last3=Song |first3=Lihua |date=2020-09-25 |title=Kirner's deformity of the fifth finger: A case report |journal=Medicine |language=en-US |volume=99 |issue=39 |pages=e22294 |doi=10.1097/MD.0000000000022294 |pmid=32991433 |pmc=7523806 }}

This condition can be diagnosed by physical examination and radiographic imaging, including X-rays, magnetic resonance imaging, etc.{{cn|date=September 2022}}

This condition can be confused with other malformations (congenital and acquired) of the hand, these include:

• Camptodactyly{{Cite journal |last1=Dubrana |first1=F. |last2=Dartoy |first2=C. |last3=Stindel |first3=E. |last4=Fenoll |first4=B. |last5=Le Nen |first5=D. |last6=Lefevre |first6=C. |date=1995 |title=[Kirner's deformity. 4 case reports and review of the literature] |journal=Annales de Chirurgie de la Main et du Membre Supérieur |volume=14 |issue=1 |pages=33–37 |doi=10.1016/s0753-9053(05)80532-0 |pmid=7535545}}{{cite journal |title=Kirner's Syndrome: Displaced Bone – Misplaced Diagnosis |url=https://indianpediatrics.net/july2018/625.pdf |first1=Vijay |last1=Viswanathan |first2=Abhijit V. |last2=Mhapankar |journal=Indian Pediatrics |year=2018 |volume=55 |issue= 7|pages=625–|doi=10.1007/s13312-018-1314-4 |doi-access=free |pmid=30129560 |s2cid=52046544 }}
• Clinodactyly{{Cite journal |last1=Dubrana |first1=F. |last2=Dartoy |first2=C. |last3=Stindel |first3=E. |last4=Fenoll |first4=B. |last5=Le Nen |first5=D. |last6=Lefevre |first6=C. |date=1995 |title=[Kirner's deformity. 4 case reports and review of the literature] |journal=Annales de Chirurgie de la Main et du Membre Supérieur |volume=14 |issue=1 |pages=33–37 |doi=10.1016/s0753-9053(05)80532-0 |pmid=7535545}}{{cite journal |title=Kirner's Syndrome: Displaced Bone – Misplaced Diagnosis |url=https://indianpediatrics.net/july2018/625.pdf |first1=Vijay |last1=Viswanathan |first2=Abhijit V. |last2=Mhapankar |journal=Indian Pediatrics |year=2018 |volume=55 |issue= 7|pages=625–|doi=10.1007/s13312-018-1314-4 |doi-access=free |pmid=30129560 |s2cid=52046544 }}
• Mallet finger{{Cite journal |last1=Walsh |first1=Catherine |last2=Sills |first2=Matthew |last3=Markey |first3=Gerard |date=2018-11-01 |title=An 11-year-old with mallet finger |journal=Emergency Medicine Journal |language=en |volume=35 |issue=11 |pages=679–680 |doi=10.1136/emermed-2017-207361 |pmid=30337418|s2cid=53013535 }}
• Fracture{{Cite journal |last1=Khalid |first1=Saifullah |last2=Khalid |first2=Mohd |last3=Zaheer |first3=Samreen |last4=Ahmad |first4=Ibne |last5=Ullah |first5=Ekram |date=2012 |title=Kirner's Deformity Misdiagnosed as Fracture: A Case Report |url=https://www.academia.edu/2718835 |journal=Oman Medical Journal |volume=27 |issue=3 |pages=237–238 |doi=10.5001/omj.2012.53 |pmid=22811775 |pmc=3394366 }}
• Brachydactyly type A3 (also known as brachymesophalangy type V){{Cite web |title=Entry - %128000 - DYSTELEPHALANGY - OMIM |url=https://omim.org/entry/128000#7 |access-date=2022-09-02 |website=omim.org |language=en-us}}

This hand difference is estimated to be present in 0.15%-0.25% of the world population.{{Cite journal |last1=Tianxiao |first1=Ma |last2=Wang |first2=Dongyue |last3=Song |first3=Lihua |date=2020-09-25 |title=Kirner's deformity of the fifth finger: A case report |journal=Medicine |language=en-US |volume=99 |issue=39 |pages=e22294 |doi=10.1097/MD.0000000000022294 |pmid=32991433 |pmc=7523806 }}

It is more common in women than in men; physical examination performed on people from a selected region in southern England by David and Burwood et al. found 18 individuals from 9 families with Kirner's deformity. Of these 18 individuals, 6 were men and 12 were women.{{Cite journal |last1=David |first1=T. J. |last2=Burwood |first2=R. L. |date=1972-12-01 |title=The nature and inheritance of Kirner's deformity |journal=Journal of Medical Genetics |volume=9 |issue=4 |pages=430–433 |doi=10.1136/jmg.9.4.430 |pmc=1469067 |pmid=4646550}}

It has a higher incidence rate among the Japanese.{{Cite journal |last1=Khalid |first1=Saifullah |last2=Khalid |first2=Mohd |last3=Zaheer |first3=Samreen |last4=Ahmad |first4=Ibne |last5=Ullah |first5=Ekram |date=May 2012 |title=Kirner's Deformity Misdiagnosed as Fracture: A Case Report |journal=Oman Medical Journal |volume=27 |issue=3 |pages=237–238 |doi=10.5001/omj.2012.53 |pmc=3394366 |pmid=22811775}}

A handful of treatment methods resulting in successful improvement of Kirner's deformity have been described, these include:

• Bonola's technique{{cite journal | pmid=9303047 | doi=10.1016/s0753-9053(82)80049-5 | title=[Kirner's disease: surgical treatment] | journal=Annales de Chirurgie de la Main | year=1982 | volume=1 | issue=1 | pages=88–91 | last1=Mantero | first1=R. }}
• Serial splinting{{cite journal | doi=10.1016/S0363-5023(86)80095-8 | title=Kirner's deformity: A review of the literature and case presentation | journal=Journal of Hand Surgery | date=January 1986 | volume=11 | issue=1 | pages=28–32 | last1=Freiberg | first1=A. | last2=Forrest | first2=C. | pmid=3944436 }}
• Corrective osteotomy{{cite journal | doi=10.1097/BPB.0000000000000042 | title=Percutaneous corrective osteotomy for Kirner's deformity | year=2014 | last1=Gamo | first1=Kazushige | last2=Kuriyama | first2=Kohji | last3=Uesugi | first3=Ayako | last4=Nakase | first4=Takanobu | last5=Hamada | first5=Masayuki | last6=Kawai | first6=Hideo | journal=Journal of Pediatric Orthopaedics B | volume=23 | issue=3 | pages=277–281 | pmid=24590256 }}{{Cite web |title=Kirner deformity - General Practice notebook |url=https://gpnotebook.com/simplepage.cfm?ID=x20100106202830724280 |access-date=2022-09-01 |website=gpnotebook.com}}{{Cite journal |last1=Horii |first1=Emiko |last2=Otsuka |first2=Junko |last3=Koh |first3=Shukuki |date=2018-02-26 |title=Surgical Treatment for Kirner's Deformity—Single Osteotomy through a Palmar Approach |journal=Plastic and Reconstructive Surgery Global Open |volume=6 |issue=2 |pages=e1683 |doi=10.1097/GOX.0000000000001683 |pmc=5865914 |pmid=29616176}}
• Physeal obliteration
• Distance lengthening

The following subsections comprise Kirner deformity's non-syndromic and syndromic associations:{{Cite journal |last=Lee |first=Fred A. |date=1968-12-01 |title=Generalized Overconstriction of Long Bones and Unilateral Kirner's Deformity in a deLange Dwarf |journal=American Journal of Diseases of Children |volume=116 |issue=6 |pages=599–603 |doi=10.1001/archpedi.1968.02100020603005 |pmid=5697191 }}

• Myositis ossificans
• High-arched foot
• Genu valgus
• Congenital heart defect

These are the syndromes associated with this malformation

• Turner syndrome
• Silver syndrome
• Cornelia de Lange syndrome
• Down syndrome

• Brachydactyly type D
• Syndactyly
• Minor physical anomalies

{{reflist}}

Category:Congenital disorders of musculoskeletal system