Anterior oblique ligament reconstruction for pediatric carpometacarpal joint instability
Click Here to Manage Email Alerts
A 10-year-old female patient with no pertinent medical or surgical history presented to the orthopedic hand surgeon 2.5 weeks after hitting the dorsal aspect of her left thumb on her desk while playing at school.
She was initially treated at an outside urgent care facility with a thumb spica splint. Radiographs of the left hand taken at the first office visit demonstrated a skeletally immature patient with dorsoradial subluxation of the first metacarpal on the trapezium (Figure 1). No associated fractures were visualized.
Despite attempts at reduction in the office, there was persistent incongruity of the first carpometacarpal (CMC) joint. Therefore, the patient was indicated for closed reduction and percutaneous pinning (CRPP) in the OR. Intraoperative fluoroscopy from the procedure demonstrated a successive and stable reduction (Figure 2). The K-wire was removed at 5 weeks postoperatively, and radiographs at 2 months postoperatively demonstrated maintained reduction (Figure 3). The patient was pain free and had returned to all activities and thus was advised to follow-up as needed.
Source: Hilary T. Campbell, MD; Michele Cerasani, MD; and Omri Ayalon, MD
She re-presented to the office at 2 years postoperatively, and was now 12 years old, with new left thumb pain and deformity after a fall onto an outstretched left hand a few days prior to presentation. On examination, she had tenderness and swelling at the base of the thumb, with flattening of the thenar arch. Her first CMC joint was unable to be passively moved, and she was neurovascularly intact. Radiographs of the left hand demonstrated a skeletally immature patient with dorsoradial subluxation of the first metacarpal on the trapezium (Figure 4). Again, no fractures were identified.
What are the next best steps in management of this patient?
See answer below.
Flexor carpi radialis tendon autograft to reconstruct the anterior oblique ligament
Due to this patient’s recurrent instability after a prior CRPP, the decision was made to perform an open ligament reconstruction to restore stability to the first CMC joint. The technique used is a modification of the one described by Richard G. Eaton, MD, and colleagues for adult patients.
Surgical technique
A 4-cm incision was made at the base of the thumb and carried ulnarly across the wrist crease. Dorsoradial branches of the superficial radial nerve were protected. The interval between the abductor polices longus (APL) and extensor pollicis brevis was used to identify the joint capsule. The capsule was noted to be patulous. An arthrotomy was made and the joint was inspected. There was no cartilage injury. The joint was directly reduced.
A transverse incision was then made approximately 2 cm proximal to the wrist crease to identify the flexor carpi radialis (FCR) tendon. A counter incision was made proximally to harvest the tendon slip. The ulnar half of the FCR was harvested. A burr was used to make a tunnel from the dorsal aspect of the base of the first metacarpal to the volar aspect. The distally based strip of FCR was then rerouted from its insertion on the second metacarpal through the drill hole from volar to dorsal. The graft was then passed deep to the APL in the first dorsal compartment, sutured to the APL and finally back on itself (Figure 5).
A 1.6-mm K-wire was placed from the first metacarpal into the second metacarpal above the level of the physis for supplemental fixation to maintain reduction. The first CMC joint capsule and skin were closed in a layered fashion. The patient was placed into a plaster thumb spica splint and discharged the same day.
Postoperative rehabilitation
The patient was immobilized in a thumb spica splint for 4 weeks. The K-wire was removed at 4 weeks postoperatively. Radiographs of the left hand at 5 weeks postoperatively demonstrated maintained reduction of the first CMC joint (Figure 6).
After a course of occupational hand therapy, the patient was able to regain full motion and strength in the thumb and has had no episodes of recurrent instability since surgery.
Discussion
The thumb CMC joint is a biconcave saddle joint. There are four articulations:
- trapezium and first metacarpal;
- trapezium and second metacarpal;
- trapeziotrapezoid; and
- scaphotrapezial.
The trapezium also has a volar groove for the FCR tendon. The CMC joint has motion in the following three planes:
- flexion-extension;
- abduction-adduction; and
- pronation-supination.
Although the saddle relationship of the joint provides some degree of stability, it relies heavily on capsular and ligamentous support for stabilization. There are four major ligaments:
- anterior oblique ligament (AOL);
- intermetacarpal;
- dorsoradial; and
- posterior oblique ligament.
The AOL, also known as the volar beak ligament, passes from the volar tubercle of the trapezium to the articular margin on the ulnar first metacarpal base. It is maximally taut with the metacarpal in flexion, abduction and supination. Cadaveric and biomechanical studies have demonstrated that both the AOL and dorsoradial ligament are the two primary stabilizers to dorsal translation of the first metacarpal.
There is no standardized treatment algorithm for CMC instability in the pediatric population. In the adult population, closed reduction with splint immobilization or CRPP are the main treatment options for acute and reducible CMC dislocations. CRPP is employed in reducible but unstable dislocations. If there is no subluxation on serial radiographs, this implies competency of the capsuloligamentous attachments, and this treatment can be a successful definitive management.
N. A. R. Watt, MA, FRCSED, and colleagues published their series of 12 patients, nine of which were treated with closed reduction and casting and the other three with CRPP. The authors found that in seven of the 12 patients, the joint was stable, and patients were asymptomatic at follow-up following early closed reduction. All seven patients underwent reduction the day of injury, six treated with casting only and one with K-wire fixation and casting. However, the five patients who underwent late reductions resulted in persistent subluxation and joint incongruency, which suggests that a delay in treatment results in capsuloligamentous attenuation. Late reductions in their series occurred between 3 and 21 days following the dislocation event. Based on these findings, they recommend ligament reconstruction in patients with either delayed presentations or chronic laxity or instability.
Other authors, however, advocate for acute ligamentous reconstruction. Peter T. Simonian, MD, and Thomas E. Trumble, MD, compared early ligamentous reconstruction using a slip of the FCR tendon as described by Eaton and colleagues to CRPP in 16 adult patients with isolated first CMC dislocations who failed closed reduction attempts. Four of the eight patients treated with CRPP alone within 2 weeks of injury required revision surgery for recurrent instability. Furthermore, they reported patients who underwent early ligamentous reconstruction had superior pain scores, range of motion (ROM), pinch strength and less degenerative changes on radiographs at 2-year follow-up.
The literature on thumb CMC joint dislocations in the pediatrics population is limited to case reports. Iulian Nusem, MD, and colleagues reported the successful case of a closed reduction and spica casting for an isolated thumb CMC joint dislocation in a 10-year-old female patient. During the period of immobilization, a CT scan confirmed no bony injury and congruency of the first CMC joint. At 2 years postoperatively, she was pain free and regained full motion.
Sokratis E. Varitimidis, MD, and colleagues performed an AOL reconstruction using a slip of the FCR (as described by Eaton and colleagues in adults) as a supplement to CMC joint pinning in an 11-year-old male patient with a reducible but unstable thumb CMC joint dislocation. At 18-month follow-up, the patient had recovered full function and the joint was stable.
More recently, Thomas G. Knoedler, MD, and colleagues reported on their success with bilateral AOL reconstructions using partial APL autograft with supplemental mini-tightrope stabilization (Arthrex) in a 14-year-old male patient with a connective tissue disorder with recurrent bilateral thumb CMC joint instability. Prior to this, the patient failed casting, CRPP and isolated mini-tightrope stabilization. Five-year follow-up demonstrated good ROM and strength, and improved QuickDASH scores.
In the case of our patient, CRPP was first pursued following injury due to the subacute nature of her initial presentation. It is important to highlight that this treatment was successful for 2 years postoperatively prior to a repeat trauma to the effected joint. Given the high likelihood of capsuloligamentous disruption in the setting of reinjury, the decision was made to proceed with ligamentous reconstruction. Whether primary AOL reconstruction at the time of the index procedure would have reduced the risk of reinjury is unknown, but at this time, there is insufficient evidence to support this more aggressive treatment approach.
Key Points:
- Acute CRPP can successfully restore CMC joint congruity and function in first-time, traumatic, reducible but unstable CMC joint dislocations in pediatric patients.
- FCR tendon extra-articular reconstruction of the AOL is a viable option for recurrent CMC joint dislocation in pediatric patients with capsuloligamentous incompetency.
- References:
- Bettinger PC, et al. J Hand Surg Am. 1999;doi:10.1053/jhsu.1999.0786.
- Eaton RG, et al. J Bone Joint Surg Am. 1973;55:1955-1666.
- Hove LM. Scand J Plast Reconstr Surg Hand Surg. 1993;27:317-319.
- Knoedler TG, et al. J Hand Surg Glob Online. 2021;doi:10.1016/j.jhsg.2021.07.001.
- Neumann DA, et al. J Orthop Sports Phys Ther. 2003;doi:10.2519/jospt.2003.33.7.386.
- Nusem I, et al. J Pediatr Orthop B. 2001;10:158-160.
- Simonian PT, et al. J Hand Surg Am. 1996;doi:10.1016/S0363-5023(96)80195-X.
- Varitimidis SE, et al. J Hand Surg Am. 1999;doi:10.1053/jhsu.1999.0505.
- Watt N, et al. J Hand Surg Br. 1987;doi:10.1016/0266-7681_87_90024-6.
- For more information:
- Omri Ayalon, MD; Hilary T. Campbell, MD; and Michele Cerasani, MD, can be reached at the division of hand surgery at New York University Langone Health in New York. Natalie Tanner, BA, can be reached at Drexel University College of Medicine in Philadelphia. Ayalon’s email: omri.ayalon@nyulangone.org. Campbell’s email: hilary.campbell@nyulangone.org. Cerasani’s email: michele.cerasani@nyulangone.org. Tanner’s email: njt52@drexel.edu.
Collapse
Read more about
Click Here to Manage Email Alerts