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Abstract

Purpose:

The Elson technique is a rigid reconstruction method for a hypoplastic or absent sagittal band in the treatment of chronic extensor digitorum communis (EDC) tendon dislocation. We performed a modified procedure based on the Elson technique for reconstruction of the radial sagittal band in case involving the index finger. We investigated the postoperative outcomes of chronic EDC dislocation after treatment with the original and modified Elson technique.

Methods:

We examined five fingers of five patients (2 males and 3 females) with a mean age of 41 years. The chronic EDC tendon dislocation was due to an old trauma, or a spontaneous or congenital condition involving the index in two, middle in two, and ring finger in one patient. Sagittal band reconstruction was performed using the modified Elson technique for the index finger and the original technique for the other fingers. The mean duration of postoperative follow-up was 58 months. Clinical findings such as pain and discomfort at metacarpophalangeal flexion associated with the tendon dislocation, range of motion (ROM), and disabilities of the arm, shoulder and hand were evaluated. We also examined postoperative recurrence and subjective patient evaluation.

Results:

All cases achieved pain-free stability of the EDC tendon with no recurrence, and full ROM was maintained at the latest examination after surgery. The postoperative subjective evaluation by the patients was “very satisfied” in four fingers and “neutral” in one finger.

Conclusion:

We demonstrated our modified Elson technique for the treatment of chronic extensor tendon dislocation of the index finger.

Keywords

chronic dislocation extensor digitorum communis tendon index finger reconstruction sagittal band

Introduction

Dislocation of the extensor digitorum communis (EDC) tendon over the metacarpophalangeal (MCP) joints is mostly caused by disruption of the sagittal band that acts as the main lateral stabilizer,¹ although the etiology of EDC tendon dislocation remains controversial.^2
–4 Causes of EDC tendon dislocation are divided into the rheumatoid and nonrheumatoid groups,^2,5

–8 with the nonrheumatoid group further subdivided into the traumatic and nontraumatic groups with spontaneous or congenital tendon dislocations resulting from a hypoplastic or absent sagittal band.^2,8,9 The EDC tendon dislocation commonly occurs post-trauma or in the rheumatoid hand, with cases involving spontaneous or congenital conditions rare.⁵ The presenting features are pain, swelling, and impairment of active MCP joint extension, associated with “locking” or “snapping” of the extensor tendon.¹

Conservative treatment using a splint is successful for dislocations associated with fresh injuries.¹⁰ On the other hand, most cases with chronic EDC tendon dislocation do not respond to conservative treatment.^11,12 Previous studies have described a number of surgical techniques aimed at centralizing and stabilizing the EDC tendon over the MCP joint.^{9,11,13

–18} We used the Elson technique^6,18 to reconstruct the sagittal band for maintaining tendon centralization in the treatment of chronic EDC tendon subluxation or dislocation at the MCP joint. In addition, in the cases involving the index finger, we performed a modified procedure in which the tendon slip was passed under the radial lateral band instead of the deep transverse intermetacarpal ligament. The aim of this study was to investigate the postoperative outcomes of chronic nonrheumatoid EDC tendon dislocation at the MCP joint after treatment with the original and modified Elson technique.

Patients and methods

Patients

Between 2008 and 2015, five fingers of five patients with chronic nonrheumatoid ulnar dislocation of the EDC tendon were referred to our hospital. We retrospectively evaluated postoperative outcomes in those patients. All of the patients were Asian, and none showed any generalized ligamentous laxity or joint hypermobility. Patients included two males and three females with a mean age of 41 ± 17 years (mean ± SD, 22–61 years) (Table 1). All patients satisfied the following criteria: (1) the main complaint was chronic pain or impairment of finger extension due to extensor tendon dislocation; (2) they had undergone conservative treatment for more than 3 months using an extension splint failed; and (3) at least 3 months had passed since the time of injury. All of the patients had discomfort and snapping over the MCP joint of the involved finger on active extension. Three patients also complained of chronic mild pain at the site of extensor tendon dislocation on flexion of the MCP joint. The average interval from surgery to follow-up evaluation was 58 months (range, 18–83 months). The involved digit was the index finger in two, middle finger in two, and ring finger in one cases. With regard to the etiology, two patients were affected by an old trauma with a post-injury period of more than 1 year, one by spontaneous events with all dislocations occurring during daily activities, and two by congenital conditions in which the patients had been vaguely aware of snapping of the involved digits at a young age and came to complain of disabling discomfort and snapping over the involved joint in adulthood (Table 1). During surgery, it was revealed that the sagittal bands could not be directly repaired in any of the cases due to an absence of or weakly developed thin bands. Institutional review board approval and informed consent from the patients were obtained for this study. This study conforms to the Declaration of Helsinki.

Table 1.

Patients with chronic dislocation of the EDC tendon.

Case	Age (years)	Sex	Occupation	Dominant hand	Finger	Cause	Follow-up (months)
1	61	Male	Sales job	Right	R-index	Old trauma	18
2	22	Female	Nurse	Right	L-index	Congenital	70
3	25	Female	Housewife	Right	L-ring	Congenital	83
4	51	Male	Mechanic	Right	L-middle	Old trauma	60
5	47	Female	Housewife	Right	R-middle	Spontaneous	60

EDC: extensor digitorum communis.

Finger, involved digit; cause, the etiology of EDC tendon dislocation; follow-up, average interval from surgery to follow-up evaluation.

Assessment of the pre- and postoperative findings

The involved finger was pre- and postoperatively evaluated on the basis of the presenting symptoms such as pain on MCP flexion and discomfort associated with “dislocation,” “locking,” or “snapping” of the extensor tendon. We assessed pre- and postoperative range of motion (ROM) of the MCP as well as that of the proximal interphalangeal (PIP) joint at the latest assessment after surgery (18–83 months) to clarify whether the full ROM was maintained. The postoperative disabilities of the arm, shoulder, and hand (DASH) score and the recurrence of postoperative EDC tendon subluxation or dislocation on MCP joint flexion were also evaluated. The patients were asked to subjectively evaluate the surgical outcomes on a 4-point scale of “very satisfied,” “satisfied,” “neutral,” or “dissatisfied” at the latest postoperative examination. In addition, we compared the surgical outcome of the treatment with the modified Elson technique with the outcomes achieved using the original Elson technique. The sagittal band reconstruction was performed by senior surgeons (NT and KI), and postoperative evaluations were independently conducted by other surgeons (MH, YO, and KK).

Surgical technique

We used an EDC tendon slip to stabilize the dislocated extensor tendon of the index finger during treatment with the modified Elson technique. Briefly, a longitudinal incision was made over the dorsal aspect of MCP joint, and the whole extensor apparatus was exposed. A finding of EDC and extensor indicis proprius (EIP) tendon dislocation with the MCP joint in a flexed position and a lax or thin sagittal band was confirmed (Figure 1(a)). The EIP tendon was proximally divided at the distal base to form a slip consisting of half of the tendon’s full width and approximately 4 cm in length proximal to the MCP joint on the radial side (Figures 1(b) and 2(a)). This EIP tendon slip was passed under the second EDC and the first dorsal interosseous muscle tendon (Figure 1(c)) due to the anatomical absence of the deep transverse intermetacarpal ligament on the radial side. The tendon slip was laterally looped (Figure 1(d)), returned over the second EDC and EIP, passed under the EIP tendon and through the space between the EIP and second EDC tendons (Figures 1(e) and 2(b)), and then sutured on the half-slip tendon itself (Figure 1(f)). The tendon reconstruction was tensioned with the MCP joint and wrist in full extension with slight overcorrection on the ulnar drift. For cases in which the middle or ring finger was involved, we used the original Elson technique.^6,18 The EDC tendon was proximally divided at the distal base to form a slip consisting of one-third of the tendon’s full width on the radial side. The tendon slip was passed under the deep transverse intermetacarpal ligament on the radial side, laterally looped, and returned to the tendon. The tendon slip was then sutured after adjusting the tension (Figure 2(c)). Postoperatively, unlimited active ROM was allowed for extension and that for flexion limited to 60° for 3 weeks using a splint. Active ROM exercise was started to encourage full motion of the MCP joint at 3 weeks, and ROM restrictions were discontinued at 8 weeks after surgery. Postoperative treatment did not involve any formal strengthening program.

Figure 1.

Sagittal band reconstruction for EDC tendon dislocation in the left index finger using the modified Elson technique. The presence of ulnar EDC (black arrow) and EIP (white arrow) tendon dislocation with the MCP joint in a flexed position and a thin sagittal band (black arrow head) was confirmed (a). The EIP tendon was proximally divided at the distal base on the MCP joint level to form a tendon slip consisting of the radial half of the width of the EIP tendon and approximately 4 cm in length proximal to the MCP joint (white arrow) (b). The tendon slip was passed under the second EDC and the first dorsal interosseous muscle tendon (black arrow) instead of the deep transverse intermetacarpal ligament (c), and then laterally looped and returned over the tendon (d). The free end of the tendon slip (black arrow head) was passed under the EIP tendon and through the space (white arrow head) between the EIP (white arrow) and second EDC tendon (black arrow) (e). Tendon reconstruction was tensioned with the MCP joint and wrist in full extension with slight overcorrection on the ulnar drift (e), and then sutured on the half-slip (black arrow head) itself after adjusting the tension (f). EDC tendon recentralization on MCP extension and flexion was confirmed (f). EDC: extensor digitorum communis; EIP: extensor indicis proprius; MCP: metacarpophalangeal.

Figure 2.

Schema of the modified and original Elson technique. The modified Elson technique for the index finger involves the radial tendon slip of the EIP being passed under the second EDC and the first dorsal interosseous muscle tendon, laterally looped, returned over the second EDC and EIP, and then passed under the EIP tendon and through the space between the EIP and second EDC tendons (a, b). The original Elson technique for the middle finger involves the radial tendon slip of the third EDC tendon being passed under the deep transverse intermetacarpal ligament on the radial side, laterally looped, and then returned to the tendon (c). EDC: extensor digitorum communis; EIP: extensor indicis proprius.

Results

With regard to the intraoperative findings, congenital and spontaneous cases related at thin or absent radial sagittal band and the absence of junctura as anatomical anomalies. In the old trauma cases, we found only remnants of the radial sagittal band. All patients were symptom-free and the EDC tendon demonstrated pain-free stability without subluxation on MCP joint flexion, with a full ROM of the MCP, PIP, and DIP joints at about 12 weeks after surgery, which was maintained at the latest postoperative evaluation (Table 2). The average postoperative DASH score was 2.8 (0–5). With regard to the subjective evaluation by patients, four responded that they were “very satisfied” and one was “neutral” (Table 2). All patients returned to their normal occupations and function by 12 weeks after the surgery. No complications, including infection, joint stiffness, or recurrent tendon instability, were encountered although hypertrophic scarring was observed in one case.

Table 2.

Postoperative outcomes after treatment with the modified or original Elson technique.

Case	Surgery	Complication	Recurrence	Preoperative ROM (°)		Postoperative ROM (°)		DASH	Subjective evaluation
Case	Surgery	Complication	Recurrence	Ext	Flex	Ext	Flex	DASH	Subjective evaluation
1	Modify	—	—	0	70	10	80	2.1	Very satisfied
2	Modify	—	—	35	90	35	90	2.5	Very satisfied
3	Original	—	—	ND	ND	30	90	0	Very satisfied
4	Original	—	—	10	85	10	85	5	Very satisfied
5	Original	hypertrophic scar	—	20	90	20	90	4.2	neutral

ROM: range of motion; DASH: disabilities of the arm, shoulder, and hand; ext: extension; flex: flexion; ND: not determined.

Surgery, modified or original Elson technique; complication, postoperative complication; ROM, preoperative or postoperative ROM of the metacarpophalangeal joint; subjective evaluation, the patients were asked to subjectively evaluate the surgical outcomes at the latest postoperative examination.

Discussion

There are number of studies concerning the postoperative outcomes for EDC tendon dislocation treated by a variety of surgical techniques.^{6,9,11,13

–19} Several studies have reported good postoperative outcomes for dislocations associated with spontaneous or congenital causes by reconstruction of the juncturae tendini or sagittal band,^2,5,8,20, which is consistent with our results for treatment with the original and modified Elson technique. However, those studies were based on the postoperative outcomes over relatively short follow-up periods of less than 2 years. In the cases of EDC tendon dislocation resulting from congenital or spontaneous conditions, in particular, it is unclear whether reconstruction of the congenitally absent or incomplete sagittal band will allow appropriate function or lead to additional stress on the EDC tendon in long term. We, therefore, think that long-term follow-up after surgery is important for the accurate evaluation of the postoperative outcome in such cases. Thus, we believe that the present study offers new information with regard to the long outcomes of sagittal band reconstruction for chronic EDC tendon dislocation.

The Elson technique^6,18 involves rigid reconstruction for the treatment of chronic EDC tendon dislocation in pathologies characterized by a hypoplastic or absent sagittal band.^2,8,9 Previous studies demonstrated that patients treated with this technique remained symptom-free with no recurrent dislocation of the tendon or other complications,^2,18,20 similar to the postoperative outcomes in this study. We, therefore, believe that the Elson technique^6,18 is suitable for the treatment of chronic EDC tendon dislocation in the cases involving the middle, ring, or little finger resulting from an old trauma or spontaneous or congenital causes.

On the other hand, the Elson technique cannot be used for the reconstruction of ulnar EDC tendon dislocation in the index finger due to the anatomical absence of a deep transverse intermetacarpal ligament on the radial side. We, therefore, designed a modified Elson technique in which the tendon slip was passed under the first dorsal interosseous muscle tendon. There are a few previous reports regarding the surgical treatment of EDC tendon dislocation in the index finger. The sagittal band reconstruction techniques described in those reports involve the stabilization of the tendon half-slip anchored to the radial side of the capsule⁵ or looped around the radial collateral ligament,¹¹ or the plication of the radial sagittal band and wrapping of the EDC tendon using the band.¹⁹ However, most of those procedures were performed for the treatment of traumatic tendon dislocation, and postoperatively required immobilization of the involved finger in a splint for relative long period of 3 to 6 weeks.^5,11,19 In this study, we demonstrated successful postoperative outcomes of the modified Elson technique in our small case series. We, therefore, need further study based on a large number of patients to confirm that the modified Elson technique is useful for the surgical treatment of chronic EDC tendon dislocation in the index finger.

Conclusion

In conclusion, we have demonstrated at surgical approach based on modified Elson technique for chronic EDC and EIP tendon dislocation in the index finger and reported successful postoperative outcomes in our small case series.

Footnotes

Authors’ note

The manuscript contains original material. Neither the article nor any part of its essential substance, table, or figures has been or will be published elsewhere. All the named authors were actively involved in the planning, enactment, and writing up of the study.

Acknowledgment

The authors would like to thank Dr. Takuro Wada (Division of Orthopedic Surgery, Saiseikai Otaru Hospital) for his advice and invaluable contributions to this study.

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Megumi Hanaka

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