Current concepts in the management Radial Longitudinal Deficiency

Abstracts

Radial longitudinal deficiency represents a spectrum of musculoskeletal hypoplasia and dysplasia affecting the upper limb involving mainly the radial aspect of the forearm, wrist, and hand and not infrequently the proximal arm. 2/3rd of the patients with this condition suffer from an associated medical or musculoskeletal disorder and 1/3rd of them show features of a well-known syndrome with systemic manifestations. Hence it is mandatory to do a detailed clinical, radiological and laboratory evaluation which should also include genetic counselling and assessment. Its management has evolved greatly since the beginning of last century. The vast variations developed for the treatment only reflects on the persisting controversy on the ideal treatment which still eludes the medical fraternity. Current treatment options for wrist deformities include radialization or centralization with or without distraction which unfortunately has often shown poor outcomes with high rates of recurrence and poor growth of ulna leading some workers to suggest alternative techniques, which include microsurgical reconstruction using the proximal fibula and the second toe. The management of the associated hypoplastic thumb has been encouraging with recent improvements in classifications and increased options for milder deformities. The article reviews the management options available for this common condition with respect to the recent developments in literature

1. Introduction

Radial longitudinal deficiency (RLD) is the commonest longitudinal deficiency in the upper limb and is represented by dysplasia and hypoplasia of varying degree involving the radial half structures of the limb.^1,2 Its frequency has been reported in the range from 1 in 5000 to 1 in 50,000 births.^1,2 The severity varies from involvement of the arm, radial aspect of the forearm, wrist, and hand to that of a mild hypoplasia of the thumb.1, 2, 3 1/3rd of them are isolated deformities and a majority of them result from sporadic mutations.^1,2 2/3rd of the affected patients suffer from an associated medical or musculoskeletal deficiency and 1/3rd of them show features of a well-known syndrome with atypical inheritance pattern (Table 1).2, 3, 4, 5 As the severity increases, the relation with an associated condition also increases. In this regard, it is extremely important for a hand surgeon to perform a detailed evaluation in liaison with a paediatrician and look for systemic manifestation.

Table 1.

Common Syndromic manifestations in Radial Longitudinal deficency⁴.

Syndrome	Inheritance	Clinical feature
TAR: Thrombocytopenia-absent radius syndrome	Autosomal recessive	Hypomegakaryocytic thrombocytopenia (reduced number of megakaryocytes, leading to a reduced number of platelets) and bilateral absence of the radii with presence of normal thumbs. Additional disorder: cow-milk allergy, anomalies of the kidney, heart, or lower limbs
VACTERL: Vertebral anomalies, anal atresia, cardiac abnormalities, tracheoesophageal fistula, renal anomalies, and limb anomalies	Sporadic1/Autosomal recessive/complex/	Absent or hypoplastic thumbs, syndactyly, polydactyly and radial dysplasia. Other associations: hydrocephalus
Holt-Oram syndrome	Autosomal dominant	Heart and limb phenotype vary greatly. hypoplastic,or triphalangeal thumb, Radial deficiency, ulnar deficiency
Fanconi anemia	Autosomal recessive/X-linked	Aplastic anemia, which usually presents during mid-childhood. Radial longitudinal deficiency, pigmentary changes in the skin, renal defects, Risk of acute myelogenous leukemia, solid tumors of the head, neck, breast, liver, esophagus, and vulva

1.1. Evaluation

1.1.1. Systemic manifestations assessment

Apart from the deformity affecting the extremity for which the parents often seek the opinion of an orthopaedic surgeon, the systemic manifestations may have a significant bearing on the management. Unless a detailed investigation is done, the asymptomatic features may often be missed (Table 1). It is imperative to do a comprehensive systemic and musculoskeletal clinical examination.1, 2, 3, 4, 5 A complete blood picture including platelet count and peripheral smear, ultrasound of abdomen, 2D echocardiogram along with radiographs of the spine form the part of a mandatory investigations. A chromosomal challenge test has been advocated for diagnosing an associated Fanconi anemia.^1,3, This is important as systemic manifestations like aplastic anaemia may unfold only after three years of age.It is also strongly recommended to refer a newly diagnosed child and its parents for genetic counselling for evaluation of syndromes and associated conditions.^1,3,6 An accurate diagnosis is vital for a family in order to evaluate the risk of recurrence for future conception.⁴ Recent developments in prenatal ultrasound diagnosis of upper limb anomalies and associated syndromes have shown an accuracy of as high as 70–100%.⁷ This gives a unique advantage and opportunity for a detailed counselling and discussion on the child’s diagnosis and prognosis.⁷ Parents can often make a shared decision with help of different specialists for treatable anomalies and for termination of pregnancy in case of an untreatable associated syndrome.⁷

1.1.2. Upper limb assessment

A detailed clinical evaluation of the upper limb is done including that for digital hypoplasia, wrist angulation, forearm and arm length, range of movement at elbow, forearm, wrist, thumb and other digits. Full length radiographs of the arm, elbow, forearm, wrist and hand are taken and compared with the contralateral upper limb. This is vital as the classification and management is dependent on the radiographic findings (Table 2). Stiffness of the elbow in extension is frequently encountered which is due to an absent or deficient biceps, brachialis and brachioradialis.^8,9 It is extremely important to restore passive range of movement at elbow with serial plaster and splinting before any surgical procedure as it has been reported not to improve after centralization.^8,9 Radiographs of foot is helpful in evaluation of for free vascularized metatarsophalangeal joint transfer for Villki’s procedure for the wrist deformity.¹⁰ The authors use the foot radiographs for assessment of the length for non-vascularized toe phalanx transfer in hypoplasic thumb deformities. MRI evaluation may be helpful in assessing the anatomy of the wrist particularly for microsurgical reconstruction but is not done routinely.¹⁰

Table 2.

Modified Bayne and Klug Classification of Radial Longitudinal Deficiency based on James et al. and Goldfarb et al.12, 13, 14.

Type	Thumb	Carpus	Distal Radius	Proximal Radius	Humerus
N	Hypoplastic or absent	Normal
0		Absence, hypoplasia, or coalition	Normal	Normal, radioulnar synostosis, or congenital dislocation of the radial head	Normal
1			>2 mm shorter than the ulna (Short Radius)	Normal, radioulnar synostosis, or congenital dislocation of the radial head
2			Hypoplasia (Hypoplastic radius)
3			Physis absent	Variable hypoplasia (Partially absent radius)
4			Absent (Absent radius)
5					Absent proximal humerus

1.1.3. Classification

Heikel classified the deformity into three types based on the severity of the defect in the radius.¹¹ This involved the mildest variant being hypoplasia followed by partial aplasia and the most severe form being total aplasia of radius.¹¹ This classification was further refined in to four types by Bayne and Klug based on the status of the proximal and distal radius physis.¹² James et al. further expanded the spectrum as ‘Radial Longitudinal Deficiency’ (RLD) and added hypoplastic thumb and other radial defects like congenital radio-ulnar synostosis and radial head dislocation.¹³ Goldfarb further introduced another fifth type of a more severe variant which involved deficiency of proximal humerus in addition to the variant of absent radius (Table 2).^3,14

1.2. Treatment

The deformity results in both aesthetic and functional deficits in the child.1, 2, 3, 4, 5^,11, 12, 13, 14 In severe cases the unsightly deviation of hand along with shortening of the limb significantly decreases the working space of the hand.^1,2 The aim of treatment is to correct this radial deviation and align the hand in the axis of forearm at a stable wrist, preserve motion and ensure continuing growth of the ulnar physis.² Kotwal et al. have shown the benefits of surgery in type 3 and 4 variants recently in a large series by comparing surgical with nonsurgical treatment.¹⁵ They showed that surgical correction improved wrist alignment and range of motion in digits.¹⁵ the only relative contr-indication for surgery is the presence of a stiff elbow where a surgical correction may jeopardise hand function. There is universal agreement on the initial treatment in all types of RLD. Non-operative treatment is begun at birth consisting of soft-tissue stretching and splinting which is continued until the time of corrective surgery.¹

1.2.1. Type 0-2

Type 0, 1, or mild type 2 deformities will need only a stretching and splinting program (Fig. 1, Fig. 2). There is no consensus on the treatment radial deviation deformity in the presence of adequate length of radius.⁶ Type 0 may have radial deviation deformity in addition for which a soft tissue release on the radial side with tendon transfer to the ulnar side and K-wire joint stabilisation have been advocated.¹⁶ Type 1 and 2 have more recently been treated by release of the tight radial soft tissues, tendon transfer along with radial lengthening.^17,18 Lengthening by means of uniplanar or ring fixator have been described.^17,18 Lengthening of radius is required to prevent recurrence of the radial deviation deformity.¹⁷ Takagi reported on the treatment of Type 1 and 2 RLD with radial bone lengthening and temporary external fixation between the ulna and the metacarpals.¹⁷ All cases in their series demonstrated a better range of motion and acceptable healing of the radius with no loss of correction during the follow-up.¹⁷

Fig. 1.

Radiographs showing features of a short Radius (Type 1 and 2).

Fig. 2.

Correction of deformity by soft tissue release(A) and splinting(B) in type 2 deformity

1.2.2. Type 3-4

Centralization:The traditional procedure involves Centralization in which the radially deviated carpal bones are brought over the distal ulna and aligned in the axis of the forearm.^1,2,5,6,8,9 The radial half musculoskeletal elements are hypoplastic and fibrotic (Fig. 3).^5,8,9 This includes a tight radial wrist extensors and flexors, absent or hypoplastic radial side carpal bones, joint capsule apart from the partially or completely absent radius bone.^8,9 Quite often the tight fibrous side structures are represented by a mass referred as the radial anlage (Fig. 3).¹⁹ A soft tissue release of the tight radial side hypoplastic structures including this radial anlage is also done if the wrist cannot be reduced passively onto the ulnar head (Fig. 3).^1,5,6,8,9 The bowing of the ulna if more than 30⁰ is corrected by an osteotomy at the diaphysis.¹² The correction is protected by an ulnocarpal pin in the line of third metacarpal.¹² The principle of the centralization, has undergone vast modifications since Sayre first described it in 1893.² Heikel and Lamb have described extensive reviews on the treatment options in vogue in the first six decades of the 20th century.^9,11 Two landmark articles were published by Lamb in the 70s describing the technique and results showed remarkable improvement in deformity.^8,9 In series of 117 limbs (68 patients) the average preoperative radial deviation improved from 78° to 22° in an average of five year follow up.⁹ A major drawback of the procedure was it resulted in a shortened forearm as it involved creating a notch in the carpus and placing the ulnar head in that space.^8,9 Besides the author did not inform on the movement available across the wrist and long term correction was often accompanied by spontaneous ulnocarpal fusion.^9,20 Other workers have advocated a non-notched centralization along with tendon transfers to prevent shortening and recurrence of deformity (Fig. 4).^12,21 Sestero et al. have reported that notched centralizations attained 48%, non - notched centralizations attain 58% of normal ulnar length when compared with 64% in a non-surgically treated patients.²²

Fig. 3.

Important structures to be released on the radial side of the wrist. A: Note. the presence of Radial anlage (black arrow). B) Note the presence of median nerve (yellow arrow). C) Note the exposure of the tight radial wrist extensor (red arrow – also present in B).

Fig. 4.

A: Showing the release of the tight structures on the radial side with the distal Ulna exposed after release ready for non-notched centralization. B: The ECU. has kept ready for advancement and the radial wrist extensors for transfer to the ECU. C: After correction of the deformity. D: showing the position of the k-wire close to the 3rd metacarpal.

A major hindrance to achieve alignment of the wrist is the presence of tight radial anlage and other tight soft tissues which often does not yield to surgical release or plaster cast application.¹⁸ Kessler introduced the concept of soft tissue distraction before centralization in 1989.²³ This technique brought in a significant advantage in that the gradual stretching facilitated translation of carpus distally over the end of the ulna and decreasing the risk of pressure induced distal ulnar physeal injury (Fig. 5).²³ It allowed for a balanced centralization obviating the need for notching procedures with a better preservation of wrist motion.²³ Distraction is done at a rate of 0.5–1 mm/day until the optimum position of the wrist is achieved.^6,18 The limb is maintained in the fixator for further 3–4 weeks after which a formal centralization is done.^6,18 However recent reports have not shown expected results with distraction as recurrence rates remains high.^23,24 Claire Manske et al. have observed that distraction facilitated centralization, however, it failed to prevent recurrence of deformity and was associated with a worse position when compared with subjects treated with centralization alone.²³ Skin incisions for centralization was also evolved from longitudinal incision. Different techniques have been described to bring redundant skin from the ulnar side of the wrist to the radial side which include designs by Buck-Gramko, Manske, Watson and Tonkin.⁶ All require excision of excess ulnar skin with stretching or release of the tight radial skin. Evans bi-lobed flap and a dorsal rotation flap described by van Heest have recently become more popular (Fig. 6).^1,2,6

Fig. 5.

Showing a unilateral fixator (A) for distraction and the corresponding radiographs (B).

Fig. 6.

Showing the design of the Evans bilobed incision for centralization. A: deformity, B: Incision design with the 2 lobes A and B to be transposed to the radial side. B is transposed to the site of A and A is transposed to the radial side defect. C and D: Shows the result after transposition and wound closure.

Long term results with more than 20 years follow up have shown modest results in objective assessment with centralization.^20,25 Goldfarb et al. has observed that the disability is mild, however, hand functions remains markedly abnormal and objective improvement in scores do not correlate with improved upper-extremity function.²⁵

2. Radialization

Buck-Gramcko introduced the concept of Radialization in 1985.^5,19 The term is used since the head of the ulna is placed not at the centre of carpal bones but rather at the radial side.⁵ Radial placement of the ulnar head and transfer of radial wrist muscles creates a lever arm to the ulnar side which is longer and more powerful.⁵ Since no carpal bones have to be excised, the mobility is also better.⁵ Although he showed satisfactory long-term results in his original series of radialization, objective measures were not reported.^19,24 In a subsequent publication he further advocated preoperative distraction to take away pressure on the head of ulna.^5,26 The procedure involves division of all fasciae on the radial side of the wrist and the joint Capsule (Fig. 3).⁵ The insertions of the radial wrist flexor and extensor muscles are released and the ulnar head is mobilized to be brought under the radial carpal bones.^5,19 The position is secured by a K- wire across the joint into the base of the second meta-carpal (Fig. 7).^5,19 The detached muscles are transferred end to side to the shortened extensor carpi ulnaris tendon.⁵

Fig. 7.

Note the position of the K- wire in radialization in Lateral (A) and PA views (B). Overcorrection has been achieved after release of the radial soft tissues and the pin is passed through the 2nd metacarpal.

The benefit of radialization was shown by Bhat et al. in a study involving 14 patients with type 4 RLD with a follow up ranging from 5 to 19 years (Fig. 8).²⁷ Objective assessment and subjective scoring for functional and cosmetic outcomes were done.²⁷ They showed the length of the affected ulna to be 56% of normal. The distal ulna hypertrophied to 97% of the opposite distal radius.²⁷ The median loss of correction of hand-forearm angle was 9⁰.²⁷ All hands improved on the assessment scores demonstrating the benefit of radialization. However, the authors suggested the need for secondary procedures for long-term maintenance of wrist alignment and hand function.²⁷ Geck et al. did a survivorship analysis with an end point of revision surgery for recurrence in 29 RLD limbs treated with either radialization or centralization.²⁸ 1/3rd of their patients presented with recurrence that was subsequently treated by revision centralization.²⁸ In their opinion, recurrence was associated with age less than 12 months at index procedure and immediate postoperative radial deviation position.²⁸ They suggest that the incidence of deformity recurrence can be reduced by a more ulnar translation and angulation of the wrist as a means of reducing the radial lever arm.²⁸

Fig. 8.

Note the functional results of radialization after 15 years of follow up. satisfactory wrist dorsiflexion (A), finger extension (B) and flexion (C), stability of wrist (D) has been achieved.

In another series of 21 hands with an average follow up of five years undergoing distraction with radialization, Thatte et al. demonstrated an average length of the ulna to be 72% of the normal at final follow up.²⁹ They also reported an improvement in angle of radial deviation of 64.8⁰.²⁹ However, other workers have not been able to demonstrate the benefits of distraction with radialization and have shown a higher recurrence rates.²⁴ Dana et al. did a retrospective study in eight children with Type 3 or 4 RLD who underwent preliminary soft tissue distraction followed by radialization.²⁴ The Hand Forearm Angle (HFA) which was pre-operatively 61⁰, improved to 12⁰ post-operatively, but deteriorated to 44⁰ at an average follow up of 2.6 years.²⁴

In a systematic review and meta-analysis involving 12 studies on correction of “Wrist Deformity” in radial dysplasia Murphy et al. demonstrated that there was low-quality evidence for soft-tissue distraction and centralization or radialization as the best option for correction of the hand-forearm angle in children with radial dysplasia.³⁰

3. Microsurgical epiphyseal transfer

Vilkki reported novel technique for the treatment of Bayne type III and IV radial deficiency using the second metatarsal phalangeal (MTP) joint as a vascularized graft to create a new radial column within the wrist.^31,32 The metatarsal and proximal phalanx of the second toe are transferred to the forearm to create a Y-shaped distal ulna with the potential for growth at both limbs of the “Y”.³² They presented their long-term follow-up study in Bayne type III and IV RLD of 19 wrists in 18 patients, with a mean follow-up of 11 years.³¹ The total active wrist motion averaged 83⁰. Overall ulnar growth was 67% of the contralateral side.³¹ In a more recent update they reported a modification of their procedure for type 3 hands in which a two bone forearm is created using the proximal toe metacarpal to reconstruct the entire radius.^33,34

According to the authors, this modified Vilkki procedure has the potential to correct the pathoanatomy and achieve a balanced growth with prono-supination.^33,34 Similarly Yang et al. have described a vascularized proximal fibular epiphyseal transfer based on the inferior genicular vessels for type 3 deformities.³⁵ They achieved an average correction of 28⁰ in the hand forearm angle with the forearm length being 67.9% of the normal side.³⁵ The range of wrist motion had improved to 55% of the opposite side.³⁵

Although promising, both the techniques are technically demanding and require training for microsurgical skills.

4. Lengthening of limb

Lengthening of the forearm bones in type 4 and radius in type 3 and ulna in type 3 is an attractive option to improve the working space of the hand. There has been multiple reports of small series in single digit in the recent past.¹⁸ Average length gain of 4–7 cm which is around 50–75% of total length of ulna can be expected (Fig. 9).^18,36, 37, 38, 39 However none of the reports show features of improved function of the upper limb.¹⁸ The entire process is prolonged and fraught with complications encountered invariably which include stiffness, recurrence of deformity, pin tract infections, delayed union and pain.^{6,18,36,38,39} Matsuno had reported about the need for multiple stages to achieve adequate lengthening, however in a more recent report by Yoshida et al. they showed remarkable growth retardation of the bone after lengthening, particularly after the second stage.^38,39 They recommend deferring the second stage of lengthening until the skeletal maturity.³⁹

Fig. 9.

Showing the site of osteotomy and distractor A). Note the final follow up (B and C) Showing 7 cm of lengthening. The wrist had a flexion contracture in spite of a stabilising pin at wrist as shown in A.

5. Ulnocarpal fusion

This is a salvage procedure for severe, recurrent deformity or in late presentations.⁴⁰ Pike et al. studied 12 wrists treated with ulnocarpal epiphyseal arthrodesis for recurrent radial angulation.⁴⁰ At subsequent follow up, the wrists were stable at an average of 11° of flexion and 20° of radial angulation.⁴⁰ All patients showed improvement in appearance and function. Contrary to the suggestion that arthrodesis in immature patients could result in physeal injury and further shortening, the authors showed no disturbance in extremity growth in skeletally immature extremities when the epiphysis preserving steps were carefully followed.⁴⁰ Similarly, in skeletally mature patients, Rayan reported on two patients with recurrent deformity who underwent ulnocarpal arthrodesis with improvement in both appearance and function.⁴¹

6. New directions

The recurrence of deformity still remains a major challenge for most surgeons. Quite often this is seen within the first year of correction and this had been attributed to the tight tendon transfers.²⁴ Bhat et al. have suggested that there is a mismatch of hypoplastic soft tissue structures and skeletal length in the forearm.⁴² Deviation to the radial side increases due to tight soft tissues resulting in bowing of the ulna. The persistence of the hypoplastic structure on the radial side act as a deforming lever which may not be sufficiently countered by the tendon transfers.42 Shaving of the ulnar head or carpal bones to decrease the stress of the deforming lever may lead to ulnocarpal fusion and stiffness.⁴² They have suggested a new technique of metaphyseal ulnar cuff osteotomy during radialization (Fig. 10).⁴²

Fig. 10.

Showing the steps of Ulnar cuff osteotomy. Note the site of osteotomy at the ulnar metaphysis. B: Note the overlap between carpus and the ulnar head. It has been measured to be 1 cm. C: Note overlap has been corrected by 1 cm resection of the segment of Ulna. D: Radiographs showing the site of osteotomy of the Ulna and the correction of deformity.

After soft tissue release, the overlap between carpus and ulnar head is shortened at the metaphysis in the form of a subperiosteal cuff along with additional tendon balancing (Fig. 10). This results in shortening of the ulna, but it helps in reducing the residual tightness on the radial side decreasing the deforming force of the lever.⁴² This procedure has shown promising results helping in a sustained correction in the initial vital growth period without damaging the epiphysis (Fig. 11). In the case reported by Bhat et al. the HFA correction and Hand Forearm Position (HFP) was maintained at two years of follow up.⁴² Another concept has been proposed by Vuillerman et al. where a formal centralization is not done.^43,44 The authors have suggested that centralization results in growth disturbance and additional ulnar growth retardation.^43,44 In their opinion based on literature evidence, maintenance of range of motion in the upper limb was more important for activity and self-perceived disability in RLD than wrist angulation.43, 44, 45, 46 Their procedure involves soft tissue release with bilobed flaps.^43,44 Bilobed volar or dorsal flaps are raised and all tight fascial bands and aberrant tendons are released with or without tendons transfers to the ulnar side.^35,36 No attempt is made to enter the ulnocarpal joint or dissect near the ulnar physis to avoid physeal injury.^43,44 A K-wire is inserted from the ulnar metadiaphysis to the carpus avoiding the physis in the corrected position. At 4 weeks the wire is removed and a splinting program is started. At a mean follow-up of 9.2 years, they have shown the average final radial deviation angle of 64⁰ compared with 88⁰ preoperatively at wrist.^43,44 The average active wrist flexion-extension arc was maintained at 73⁰ along with a preserved ulnar growth similar to pre-operative values.⁴⁴

Fig. 11.

Showing the results of cuff osteotomy. The correction of deformity is maintained at 2 years of follow up.

6.1. Type N

Type N generally refers to Hypoplastic thumb and will require reconstruction procedure according to the severity of grading and classification (Fig. 12, Fig. 13, Fig. 14).⁴⁶ (Table 3)

Fig. 12.

A: Showing the Abductor digiti minimi (Huber’s) transfer for opponensplasty. B: Showing the Flexor digitorum superficialis transfer (Lister’s) for. opponensplasty and Ulnar collateral ligament reconstruction at metacarpophalangeal joint.

Fig. 13.

Showing the option of non-vascularized toe phalanx transfer (C, D, E) for type 3a hypoplastic thumb (A and B). F: At 2 years follow up the toe phalanx continues to grow providing a stable thumb.

Fig. 14.

Showing results of pollicization for a floating thumb (inset).

Table 3.

Modified Blauth classification (Tonkin et al.⁴⁶) and treatment options for Hypoplastic thumb.

Grade	Clinical manifestations	Treatment
1	Narrow, small (near normal) Minimal underdevelopment Stable Mild intrinsic hypoplasia	Reassurance
2A	Narrow, small Adduction contracture Uniaxial Ulnar Collateral ligament (UCL) Metacarpophalangeal (MP) joint instability Poorly developed thenar muscles Extrinsic anomalies not demanding reconstruction	First web space release and local flap, Imbrication of UCL of MP joint, Opponensplasty (Huber’s (Abductor Digiti Minimi) (Fig. 12), Lister’s (Flexor Digitorum Superficialis (FDS)),
2B	As for 2A plus bi-axial/global MP joint instability and/or extrinsic anomalies requiring reconstruction	First web space release and local flap, Imbrication of UCL, Opponensplasty (Lister’s (FDS), if global instability at MP joint – to consider chondrodesis, extrinsic tendon transfer for Flexor Pollicis Longus/Extensor Pollicis Longus
2C	As for 2B plus inadequate Carpometacarpal (CMC) joint	As for 2B – CMC joint stabilisation with tendon graft, Pollicization (Fig. 14)
3A	Aplasia proximal 1/3 thumb MC (absent CMC joint) Severe underdevelopment Unstable Extensive intrinsic and extrinsic musculotendinous deficiencies	First web space release and local/regional flap, Imbrication of UCL or its reconstruction Opponensplasty (Lister’s (FDS), if global instability at MP joint – to consider chondrodesis, to consider toe phalanx transfer for metacarpal (Fig. 13), Pollicization
3B	As for 3A but with aplasia proximal 2/3 thumb Metacarpal (absent CMC joint)
4	Absent Metacarpal (Pouce flottant)	Pollicization
5	Absent thumb Note increasing underdevelopment	Pollicization

7. Conclusion

The ideal treatment for RLD and its multiple variants remains a popular and challenging topic of discussion among surgeons. The best treatment option still remains elusive as new techniques continues to evolve while standard techniques continues to be more rigorously tested by patient reported outcome scores. Comparisons of treatment options in the future should shed more light on this unsolved problem.

CRediT authorship contribution statement

Anil K. Bhat: Conceptualization, Formal analysis, Project administration, Resources, Supervision, Validation, Visualization, Writing - review & editing. A.M. Acharya: Data curation, Formal analysis, Resources, Software, Supervision, Validation, Visualization, Writing - original draft, Writing - review & editing.

Declaration of competing interest

None declared.