Congenital absence of lunate and triquetrum with hypoplastic scaphoid: a case report and review of literature

INTRODUCTION

The absence or hypoplasia of bones or deformities associated with various bones have been documented in the past by various authors. These absent or hypoplastic carpal bones have mostly been associated with various congenital syndromes and anomalies. Few of such documented syndromes are VACTERL syndrome and also similarly in Fanconi’s Anaemia.^1-5 Aplasia or hypoplasia have also been demarcated according to the longitudinal defects of radial elements and limb buds. It is a rare occurrence to find out any isolated aplasia, hypoplasia or complete absence of carpal bone/s without any associated syndromes or congenital anomalies.

Here, a case is reported with absent lunate and triquetrum with hypoplastic scaphoid bone without any congenital anomaly or syndrome. To the best of our knowledge so far, this combination of absence of carpal bones has not been reported.

CASE REPORT

A 20 year old male, patient presented in outpatient department clinic, with complains of pain at right wrist since 3 months. Pain was insidious in onset, dull aching, intermittent and was increased when lifting heavy weights; relieved on rest, medication and use of supports. There was no history of trauma, infection or fever. There was no history of childhood illness. He was delivered normally at term gestation. He had no history of any Intensive Care Unit visit after birth. There was no history of any deformity/defect at birth. There was no history of any prior treatment taken for wrist pain anywhere else. This was his first hospital visit regarding this wrist pain. His parents were non consanguineous. On general appearance, he looked normal built, well nourished, head looked normocephalic without abnormal facies, local examination of right wrist revealed no scar, sinus, erythema, swelling or induration. There was no visible deformity. On deep palpation there was mild tenderness near distal lateral wrist radial margin along with mild tenderness at anatomical snuff box. Thenar and hypothenar eminence of both hands were almost equal to each other. There was no upper limb length discrepancy. There was no distal neurovascular deficit. Radiographs of bilateral wrist revealed the absence of lunate, triquetrum with hypoplasia of scaphoid and radial styloid on the right wrist while all the carpal bones were normal on the left side. Furthermore, to look for any suspicious infection or soft tissue abnormality, Magnetic Resonance Imaging of the right wrist was advised which confirmed the radiological finding and there was no evidence of infection. All the structures appear normal apart from the absence of the carpals and a hypoplastic scaphoid and radial styloid.

Patient was advised and counselled regarding imaging findings and diagnosis. He was managed with Non-Steroidal Anti inflammatory drugs, muscle strengthening exercises and was advised using wrist support while lifting weights. Active range of motion was advised to prevent development of any stiffness.

DISCUSSION

The wrist and hand are part of a complex functional unit comprising of a complex anatomy and is made up with the small, muscular ligamentous complexes held along with various bony structures to provide mechanical stability. This arrangement is helpful in providing wrist joint versatile range of motion and functions that it performs. The upper limb starts developing at around 4 weeks of life. At around 8 weeks complete outline is formed.^6,7 Thus, even before pregnancy is diagnosed, almost all the abnormalities, if any in limb are already established. Cartilaginous precursors appear at around 6 weeks of intrauterine life which undergo separation and cavitation. The first carpal bone to formed is capitate followed by scaphoid, lunate, hamate and triquetrum. The congenital abnormalities have been known to occur in less than 2% of all new-borns and out of which nearly 9-10% affect upper limb.⁷

Various upper limb deformities such as club hand, radial hemimelia, carpal arrest deformities etc. that are already documented have been classified in various classification systems. The classification system of international federation of societies for surgeries of the hand, classifies these deformities into seven groups namely failure of formation; failure of differentiation; polydactyly; overgrowth; under growth; amniotic band syndrome; generalised skeletal syndromes.^2-9

Congenital malformations of upper limb vary from a great variety of small to large skeletal abnormalities which may affect little bit of functional status of the limb to a completely disabling malformation as well as deformity of the upper limb. Carpal absence is also seen in congenital extremity malformations such as intercalary radial hemimelia.^10,11

Absence of carpal bones is also seen in hereditary multicentric Idiopathic osteolysis along with tarsal osteolysis which starts between the age of 2 to 7 years. It starts spontaneously with pain and swelling in hands and feet. The progression of the disease ceases in adolescence. Non-hereditary multicentric osteolysis with nephropathy is also associated with absence of carpal and tarsal bones along with malignant hypertension and renal failure.¹²

In this case report, it is proposed that structural anomaly is due to combination of failure of formation (for lunate and triquetrum) and undergrowth (for the hypoplastic scaphoid).

Majority of the authors have reported (Table 1) absence of scaphoid, as the most common carpal bone absence with or without any other bony involvement.^1,13-23 Only one report has documented bilateral scaphoid absence.¹⁹ Most of them managed conservatively with satisfactory outcomes. Ubeda et al have reported a case of hypoplasia of scaphoid with carpal instability in which they performed arthroscopic removal of scaphoid remnant. Patient became asymptomatic after surgery.1⁷ Panciera et al have reported a case of degenerative intercarpal arthritis with absent scaphoid and lunotriquetral coalition in 45 year old male manual worker. Capitate-lunate-hamate-triquetral arthrodesis performed using staples and Herbert screws.⁴

It has been observed from the published literature that patients are more symptomatic when scaphoid is hypoplastic as compared to its absence. Hypoplastic scaphoid is generally associated with radial styloid hypoplasia. This makes carpal tunnel shallow. Radford et al reported a case of chronic median nerve compression in a 15 year old boy with hypoplastic scaphoid and radial styloid. Carpal tunnel release was performed and intraoperatively, they found carpal tunnel to be shallower than normal.¹³ Onset of intercarpal arthritis or carpal instability seems to depend on the age and extent of manual work performed although because of very small number of patients, no conclusive evidence can be drawn. Few authors have reported isolated absence of lunate.^14,15,24

CONCLUSION

It is concluded that this combination of absence of lunate and triquetrum with hypoplastic scaphoid without any syndrome is distinct entity and this is first documented report.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: Not required

REFERENCES

1. 1. Kuz JE, Smith JM. Congenital absence of the scaphoid without other congenital abnormality: a case report. J Hand Surg Am. 1997;22:489-91.
2. 2. Mesa Rivero ME, Angulo Gutiérrez J, Lara Bullón J. Absence and hypoplasia of bones del carpo. A propósito de un caso. Rev S And Traum Ort. 2011;28:48-52.
3. 3. Van Goor H, Houpt P. Bilateral congenital hypoplasia of the carpal scaphoid bone. J Hand Surg Am. 1989;14:291- 4.
4. 4. Panciera P, Le Viet D. Intercarpal degenerative arthritis in adulthood as a late consequence of unilateral congenital aplasia of scaphoid: a case report. J Hand Surg Am. 2008;33:213-6.
5. 5. Vidal Ruiz CA, Pérez-Salazar Marina D, Calzada Vázquez-Vela C, Casta˜neda Leeder P. Most common congenital anomalies of the hand. Rev Mex Ortop Ped. 2012;14:5-11.
6. 6. Dogliotti AA. Review of the description and treatment of the most frequent congenital anomalies of the hand. Cir Plast Iberolatinoam. 2017;43(1):S97-106.
7. 7. Davison EP. Congenital hypoplasia of the carpal scaphoid bone. J Bone Jt Surg Br. 1962;44:816-27.
8. 8. Gishen K, Askari M. Congenital hand anomalies: etiology, classification, and treatment. J Craniofac Surg. 2014;25:284-94.
9. 9. Streeter GL. developmental horizons in human embryo; a review of the histogenesis of cartilage and bone. Contrib Embryol. 1949;33:149-68.
10. 10. Naranjo A, Muniain MA. Primary idiopathic osteolysis; description of a family. Ann Rhem Dis. 1992;51(9):1074-8.
11. 11. O’Rahilly R, Muller F. Developmental stages in human embryos: revised and new measurements. Cells Tissues Organs. 2010;192(2):73-84.
12. 12. Singhal R, Salim J, Walker P. Idiopathic multicentric osteolysis: a case report and literature review. Acta Orthop Belg. 2005;71(3):328-33.
13. 13. Radford PJ, Matthewson MH. Hypoplastic scaphoid- -an unusual cause of carpal tunnel syndrome. J Hand Surg Br. 1987;12(2):236-8.
14. 14. Newcomb AH, Frankenkoff J. Unilateral congenital lunate absence: a case report. Sciedu Press. 2021;7(1):1-4.
15. 15. Roche AF. Absence of lunate. Roentgenol. 1967;100:523-5.
16. 16. Mavi A, Cagman B, Congenital absence of the radius, scaphoid, trapezium, thumb and hypoplasia of the lunate. Neurosciences. 2002;7(3):201-3.
17. 17. Úbeda VG, Diego RP, Martinez JME. Chronic wrist pain. Hypoplasia of the carpal scaphoid bone. Rev Esp Cir Ortop Traumatol. 2021;65:382-85.
18. 18. Postacchini F, Ippoplito E. Isolated absence of human carpal bones. Teratology. 1975;11(3):267-71.
19. 19. Patankar H. Bilateral Congenital Aplasia of the Scaphoid. J Hand Surg. 1998;23(6):817-9.
20. 20. Srivastava KK, Kochhar VL. Congenital Absence of the Carpal Scaphoid: A Case report. JBJS. 1972;54(8):1782.
21. 21. Schick N. Congenital Absence of Carpal Scaphoid. Br Med J. 1972;3(5820):236.
22. 22. Papanikolaou P, Haddadin MA. Congenital absence of carpal scaphoid. Br Med J. 1972;2(5808):292.
23. 23. Gurav RM, Patil AB. Bilateral hand malformations with absence of carpal bones with fusion of proximal metacarpals. Clin Dysmorphol 2012;21(1):56-7.
24. 24. Kobayashi H, Kosakai Y, Usui M, Ishii S. Bilateral deficiency of ossification of the lunate bone. A case report. J Bone Joint Surg Am. 1991;73(8):1255-6.
25. 25. Eraltug U. An unusual variety of partial carpal agenesis. Int Surg. 1966;46(6):594-5.
26. 26. De Smet L. Unilateral congenital absence of the lunate and scaphoid. Genet Couns. 2005;16(4):413-5.