Extensor Retinaculum Reconstruction of the Distal Radioulnar Joint in Adolescents

Abstract

Background

This study characterizes the outcomes and complications of surgical reconstruction of distal radioulnar joint (DRUJ) instability using the extensor retinaculum (Herbert sling). Our hypothesis was that extensor retinaculum reconstruction is a reliable method of DRUJ stabilization in adolescents.

Methods

This was a retrospective study of pediatric patients treated surgically using the Herbert sling for DRUJ instability at a single institution. We identified 22 subjects who underwent surgery at an average of 16.2 years of age (range, 12-18 years). Medical records and available imaging were reviewed for all subjects, and patients were contacted to participate in the prospective completion of the Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) questionnaire.

Results

Preoperative symptoms were more commonly pain (95%) than feelings of DRUJ instability (45%), although 100% had instability on physical examination. Eight (36%) patients demonstrated limited supination preoperatively. Twenty-one subjects (95%) noted prior injury to that wrist, 15 of which were distal radius fractures. Surgery consisted of stabilization of the DRUJ using extensor retinaculum, in concert with other procedures to address all potential causes of wrist pain. Postoperatively, DRUJ stability was maintained in 21 of 22 subjects. Of the 12 patients who provided functional outcome scores, median QuickDASH score was 7.6 (range, 0-45).

Conclusions

Distal radioulnar joint instability in adolescents is often preceded by fracture of the distal radius. Surgeons must maintain a high level of suspicion to appropriately diagnose DRUJ instability, which is often not an isolated pathoanatomical problem. The Herbert sling technique using extensor retinaculum can successfully confer DRUJ stability in this population.

Introduction

The distal radioulnar joint (DRUJ) is a complex joint that provides a balance of stability and motion to allow the forearm to pronate and supinate. The stability of the DRUJ is provided by a combination of the bony architecture of the distal radius and ulna and the surrounding soft tissue structures which include the joint capsule, triangular fibrocartilage complex (TFCC), and surrounding muscles. ¹ The volar and dorsal radioulnar ligaments, which are components of the TFCC, have been identified as key soft tissue stabilizers to the DRUJ. ²

Injuries of the DRUJ can lead to wrist instability, resulting in pain and decreased wrist range of motion, grip strength, and function. These injuries can be secondary to a distal radius or forearm fracture and/or an injury to the soft tissues surrounding the DRUJ, including the TFCC. ³ Distal radioulnar joint instability in adolescents is a rare problem. ⁴ Patients may present with pain at the DRUJ, along with complaints of the joint popping or dislocating with activity. ⁵ In adolescents, this instability is often secondary to a traumatic injury to the wrist, sometimes sustained many years before the complaints of DRUJ instability become apparent. ⁶

The appropriate treatment for DRUJ instability is patient-specific and can be difficult to elucidate. First, it is important to distinguish whether bony malunion of the radius and/or ulna is responsible for the instability. ⁷ If malunion alone is the cause of the DRUJ instability, then corrective osteotomy is the treatment of choice. If the DRUJ instability involves soft tissue laxity, there are multiple treatment options, including immobilization and functional bracing ⁸ as well as surgical reconstruction of the DRUJ with autograft or allograft tendon weaves with or without bony procedures.^9-11 The Herbert sling technique was described by Stanley and Herbert ¹² in 1992 as a method of using extensor retinaculum to stabilize the ulnar side of the wrist when a silastic replacement of the ulnar head was performed, which has since been advocated as an isolated surgical treatment for DRUJ instability. ⁶ This technique has particular appeal in the skeletally immature patient, as reconstruction may be performed without the risk of iatrogenic physeal disturbance, which may be seen in procedures using tendon graft passed through bony tunnels.

This study aims to characterize the outcomes and complications of a stepwise algorithm for treating DRUJ instability in adolescents, with surgical reconstruction using the Herbert sling technique. Our hypothesis was that extensor retinaculum reconstruction is a reliable method of DRUJ reconstruction in the adolescent population.

Materials and Methods

Medical Record Review

This was a retrospective study of all patients treated surgically with the Herbert sling for DRUJ instability at our pediatric tertiary care center over 2 decades (1995-2015). We identified 22 patients who underwent extensor retinaculum reconstruction of the DRUJ during our study period. A review of the medical records was undertaken to determine the age, affected side, pathological associations, subjective assessment of function, and objective range of motion and function, as well as other relevant physical examination findings. The timing of surgery and complications were recorded. Preoperative and postoperative active and passive range of motion of the affected wrist (flexion/extension; pronation/supination) were recorded, as was resolution or maintenance of symptoms. For the purposes of this study, the direction of instability was recorded as the position of the ulna in relation to the radius. Therefore, “dorsal” DRUJ instability indicates that the ulna is dorsal to the radius, and “volar” DRUJ instability indicates that the ulna is volar to the radius.

Questionnaire Administration

Patients were then contacted to participate in the prospective completion of the Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) questionnaire.^13,14 The QuickDASH has 11 items that are answered on 5-point Likert scales. The overall score is reported on a scale from 0 to 100, with 100 indicating severe disability and 0 indicating no disability. The mean score for the general US population is 11. ¹⁵ All responses to questionnaires were collected and stored using REDCap (Research Electronic Data Capture) electronic data capture tools hosted at our institution. ¹⁶

Indications for Surgery

Our algorithm begins with a thorough history and physical examination to confirm the presence of DRUJ instability. Initial standard plain wrist radiographs are obtained with particular attention paid to radiographic evidence of static DRUJ subluxation or dislocation, ulnar variance, malunion of the distal radius or ulna, or the presence of an ulnar styloid nonunion. Malunions of the distal radius and/or ulna with resulting DRUJ instability are treated with corrective osteotomy; this procedure is not the subject of the current investigation. For those patients without clear deformity, nonoperative management, including bracing and occupational therapy, is generally attempted for at least 3 to 6 months. Surgical intervention is indicated for those patients with persistent symptoms despite nonoperative management. Preoperative magnetic resonance imaging can be helpful to determine whether DRUJ instability is due to TFCC tear. Distal radioulnar joint reconstruction is indicated for those with persistent intraoperative DRUJ instability after ulnar shortening osteotomy and/or TFCC repair in the same surgical setting.

Surgical Technique

The goal of surgical intervention is to address all likely causes of symptoms, with the number and type of procedures varying by patient. Ulnar shortening osteotomy is performed if there is positive ulnar variance, with the goal of correcting the patient to neutral ulnar variance. A wrist arthroscopy is performed to determine whether there is any other intracarpal pathology and to perform a TFCC repair or debridement if a TFCC tear is present. If an ulnar styloid nonunion is present, the styloid is excised or repaired depending on the size of the fragment. Finally, stability of the DRUJ is checked intraoperatively, and if instability persists, an open DRUJ reconstruction is performed using a slip of extensor retinaculum. See Figure 1 for illustration of the surgical technique. The extensor retinaculum is carefully exposed through a dorsal Bowers approach. The proximal half of the retinaculum, which is more robust and appropriately situated than the distal half, is typically selected for use in this reconstruction. We incise the retinaculum between the fourth and fifth dorsal compartments; the extensor digiti communis (EDC) tendons are retracted radially, and the extensor digiti quinti (EDQ) proprius is retracted ulnarly to expose the ulnar aspect of the distal radius. The bone on the dorsoulnar aspect of the sigmoid notch is debrided to promote a bleeding response, and suture anchors or periosteal nonabsorbable sutures are placed. The extensor retinaculum flap is based ulnarly, passed beneath the extensor carpi ulnaris (ECU) and EDQ tendons, and imbricated using the suture anchors, such that the flap is advanced radially and proximally. The retinaculum is tensioned with the ulna reduced in the sigmoid notch, usually in supination. The repair is gently tested with range of motion. Transulnar to distal radial metaphyseal smooth pin fixation is used to protect the repair, usually with 2 parallel pins proximal to DRUJ. Postoperatively, patients are immobilized in a long arm cast, generally in supination, for at least 4 weeks. Pins are removed in the office at 4 weeks, and an additional short arm used is used for 2 more weeks. Upon final cast removal, occupational therapy is begun with slow advancement of activity over the next 6 to 8 weeks. Return to most activities is allowed at 12 weeks, with a return to sports at 24 weeks.

Figure 1.

Illustration of the Herbert sling surgical technique. (a) A dorsal Bowers-type incision is used. (b) An ulnarly based flap of the proximal half of the extensor retinaculum is created. (c) The extensor digiti quinti proprius is taken out of the retinaculum and protected with a vessel loop. The extensor digiti communis and extensor carpi ulnaris tendons are left in their respective compartments. (d) The flap is advanced radially and proximally and secured to the dorsal aspect of the sigmoid notch.

Statistical Analysis

Patient, injury, operative, and outcome characteristics were summarized by frequency and percent for characteristics and by mean and standard deviation (SD) or median and range for continuous characteristics. Patient-reported outcome data (QuickDASH) were obtained for 55% (12 of 22) of the cohort. Preoperative and postoperative characteristics were compared across patients who returned the questionnaire versus those who did not.

This study was approved by our institutional review board.

Results

Medical Record Review

The average age at the time of surgery for our 22 patients was 16.2 years (range, 12-18 years). Sixty-four percent of patients were women. Twenty-one patients (95%) reported a history of previous injury to that wrist, most of which were distal radius fractures. However, only 2 of these fractures required surgical treatment, both consisting of closed reduction and pinning of distal radius fractures. Preoperatively, the vast majority of patients complained of ulnar-sided wrist pain (95%). Four patients (18%) noted clicking. Ten patients (45%) complained of feelings of instability at the DRUJ. In addition, 1 patient had a distal radius growth arrest noted preoperatively. Three patients (14%) had undergone prior attempts at surgical treatment of their symptoms. These included 2 patients who had undergone osteotomies of the radius and/or ulna and 1 patient who had undergone TFCC repair (Table 1).

Table 1.

Demographics and Injury Characteristics.

Variable
Gender (N (%))
Female	16 (64)
Male	9 (36)
Age at surgery in years (Average (range))	16.7 (12.7-22.4)
Prior wrist injury (N (%))
Distal radius fracture	17 (68)
Wrist sprain	3 (12)
Acute DRUJ dislocation	2 (8)
Radius and ulna shaft fracture	1 (4)
Duration of preoperative symptoms in months (Average (range))	9 (0.25-53)
Prior surgical treatment for DRUJ symptoms (N (%))	4 (16)
Preoperative symptoms (N (%))
Pain	24 (96)
Feeling of DRUJ instability	11 (44)
Clicking	5 (20)
Distal radius growth arrest	1 (4)
Direction of preoperative instability (N (%))
Dorsal	19 (76)
Volar	5 (20)
Unknown	1 (4)

DRUJ = distal radioulnar joint.

On preoperative physical examination, the direction of DRUJ instability was noted for 21 of our 22 patients. Of these, 16 (73%) were dorsal and 5 (23%) were volar. Eight patients had limited forearm supination preoperatively; for these patients, supination improved from a preoperative average of 49° to 85° after surgery. Interestingly, only 1 patient had limited pronation preoperatively; this patient improved from 45° of pronation preoperatively to 70° postoperatively.

All 22 patients underwent surgical reconstruction of the DRUJ with extensor retinaculum, at a median time of 9 months after onset of symptoms (range, 0.25-53 months). Most patients underwent surgery after a minimum of 4 to 6 months of symptoms; the 2 exceptions were patients who sustained an acute injury resulting in a frank DRUJ dislocation and underwent surgery after 1 week to 1 month of symptoms. Ninety-five percent of patients underwent additional procedures at the time of surgery, including wrist arthroscopy, TFCC repair, ulnar styloid excision or repair, ulnar shortening osteotomy, and ulnar epiphysiodesis (Table 2).

Table 2.

Additional Surgical Procedures Performed During DRUJ Stabilization Surgery.

Procedure	No. (%)
Wrist arthroscopy	19 (76)
TFCC repair	14 (56)
Ulnar styloid excision or repair	12 (48)
Ulnar shortening osteotomy	6 (24)
Ulna epiphysiodesis	2 (8)

DRUJ = distal radioulnar joint; TFCC = triangular fibrocartilage complex.

Postoperatively, 21 (95%) of 22 patients maintained DRUJ stability at final clinical follow-up at a median of 7 months after surgery (range, 3-64 months). One patient who initially had a well-reduced DRUJ after surgery experienced a new traumatic injury 1 year postoperatively with recurrent instability. This instability was mild and was treated nonoperatively.

No infections or nerve injuries were noted following surgery. Four patients (18%) underwent additional surgery on the wrist during our study period. One patient underwent revision of an ulnar shortening osteotomy for hardware loosening in the early postoperative period. A second patient underwent removal of hardware at 2 years following ulnar shortening osteotomy. Two patients had new symptoms in the same wrist greater than 1 year after their index procedures. One patient sustained a reinjury and underwent wrist arthroscopy and TFCC repair 15 months after index surgery. The other patient, a gymnast, developed ECU instability and underwent ECU stabilization 4 years after index surgery.

QuickDASH Questionnaire

Twelve (55%) of the 22 patients returned the self-reported QuickDASH questionnaire. There were no differences between questionnaire responders and nonresponders with respect to age (P = .16), sex (P = .22), preoperative pain (P = .38), preoperative instability (P = .70), duration of symptoms (P = .09), or prior injury (P = .09). There were also no differences detected with respect to postoperative supination (P = .22), pronation (P = .19), flexion (P = .84), extension (P = .43), rate of complication (P = .28), or the need for additional surgery (P = .78). Of those who responded to QuickDASH, all had complete symptoms modules. Eleven reported that they worked, and 7 reported that they participated in a sport or played an instrument. Seven respondents (58%) reported scores less than 10 for the QuickDASH symptoms scale, yielding an overall median score of 7.6 (range, 0-45) (Figure 2a). The median work module score was 0 (range, 0-44), and the median sports module score was 0 (range, 0-69) (Figure 2b and 2c). There were 3 patients with a symptom module score >30: 2 patients had initial relief of symptoms but sustained new injuries postoperatively, and 1 patient had persistent pain and stiffness despite a negative comprehensive postoperative workup.

Figure 2.

Histograms of QuickDASH scores for symptoms (a; n = 12), work (b; n = 11), and sports (c; n = 7) modules.

Note. QuickDASH = Quick Disabilities of the Arm, Shoulder, and Hand.

Discussion

This series describes outcomes of extensor retinaculum reconstruction in 22 adolescent patients with distal radial ulnar joint instability. This technique has been described previously ⁶ ; however, there is not a large series detailing the outcomes of this procedure in adolescents. Our current series highlights several points which are salient to the treatment of patients with these uncommon and challenging injuries. First, although the vast majority of the patients in this series had a prior wrist injury, none had residual malunion of the radius or ulna. In our practice, bony malalignment is treated with osteotomy, and those patients were not part of this investigation. For the patients with true soft tissue instability discussed here, our algorithm of correcting positive ulnar variance with an ulnar shortening osteotomy, excising ulnar styloid nonunions, repairing the TFCC when a repairable tear is present, and finally performing a DRUJ stabilization only with persistent instability in the operating room after other repairs has been successful. Our treatment algorithm has produced sufficient stability that to our knowledge no patients have needed a reoperation for recurrent instability.

Second, 15 of the 22 patients had previous distal radius fractures, only 2 of which were treated with an operation (closed reduction percutaneous pinning) at the time of injury. This suggests that some pediatric distal radius fractures have associated injury to the TFCC and/or distal radioulnar ligaments, which may lead to persistent DRUJ instability even after bony healing. As distal radius fractures are a common injury in the pediatric and adolescent population, treating surgeons should maintain their vigilance to ensure appropriate rotational alignment has been achieved with both open and closed management.

Third, we have found that symptomatic DRUJ instability often occurs as part of a multifactorial ulnar-sided wrist pain. Concomitant pathology on the ulnar aspect of the wrist, including positive ulnar variance and TFCC tears, may distract the treating physician from the underlying DRUJ instability. The mean duration of symptoms in our cohort was 13.7 months, with pain being the most common presenting symptom. While symptomatic DRUJ instability is not commonly encountered, it should be considered as part of the differential in ulnar-sided wrist pain, especially if there is a history of a previous distal radius fracture.

Many different treatments have been described for DRUJ instability. Millard et al ⁸ advocated for nonoperative treatment of DRUJ instability with a functional forearm brace after a biomechanical study in which forearm braces were found to maintain DRUJ stability in cadavers with artificially induced DRUJ instability. Manz et al reported their results in 11 patients in which a dorsal capsular imbrication was used to treat posttraumatic instability using the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire and measuring grip strength and range of motion. Three of the patients were noted to have persistent DRUJ instability after the procedure, but the authors concluded that the overall function and satisfaction with the technique were good. ¹¹ Adams et al reported their results in 16 patients in which the DRUJ was anatomically reconstructed using a tendon graft. Outcomes were determined with the DASH and Modified Mayo Wrist Score. The group found that using this technique, normal stability was restored in 12 of 16 patients, and 15 patients had an excellent or good result. ⁹ Our results compare favorably with these series, with 21 of 22 patients maintaining stability on clinical examination and overall very good QuickDASH scores among the 12 of 22 patients who completed the survey, with an overall median QuickDASH of 7.6. As noted previously, the advantage of the Herbert sling technique is the ability to reconstruct or reinforce the dorsal radioulnar ligament without passing tendon grafts through bony tunnels of the distal radius and ulna; this is particularly helpful in the skeletally immature patient, in whom physeal disturbance is to be avoided.

There are a number of limitations inherent to our study. First, it is a retrospective review with only 12 of 22 reporting prospective functional outcomes. Ideally, a prospective functional outcome study could be established to better track these patients, however, such a study design has inherent challenges given the rarity of the condition and transience of our adolescent patient population. We did not, however, find any differences between those patients who returned questionnaires and those who did not, such that we can expect the QuickDASH scores to be reasonably representative of the whole cohort. Second, the number of patients included in our study is relatively small. Given the rarity of DRUJ instability, a larger study population would likely require multi-institutional cooperation. Finally, this cohort includes patients treated by 4 different surgeons, introducing both selection and performance bias. However, we believe that the diversity of treating surgeons supports the assertion that our current treatment algorithm is generalizable to all hand surgeons.

Despite these limitations, we conclude that the Herbert sling—combined with appropriate treatment of TFCC pathology and ulnar variance—consistently improves pain, DRUJ stability, and wrist function in patients with painful and functionally limiting DRUJ instability.