Long-term results of modified ligament reconstruction and tendon interposition for thumb basal joint arthritis

Abstract

Background:

Thumb basal joint arthritis is a common, disabling condition of the hand. Ligament reconstruction and tendon interposition (LRTI) is one of the more common surgical solutions. We performed a retrospective study to evaluate long-term radiological and clinical outcomes of modified LRTI procedures in treating thumb basal joint arthritis.

Methods:

A total of 91 hands (84 patients) with full chart records were enrolled in this study. The average age was 65.4 years, and the mean follow-up was 11.7 years (range, 1-21.6 years). We evaluated pain, joint stability, power-grip and key pinch strength, and thumb radial abduction angle as the functional outcomes, and measured the height of the trapezial space as the radiographic result.

Results:

There were 66 and 23 hands with excellent and good results, respectively. The diminution of the trapezial space was 4.2 mm in the stage III group and 5.2 mm in the stage IV group. Power-grip and key pinch strength, and thumb radial abduction angle were better in those with stage III than in those with stage IV arthritis. Sixty-eight hands were followed up >5 years, and of them, 66 showed excellent or good results.

Conclusion:

With good and durable surgical outcomes, the modified LRTI procedure could be a good treatment for thumb basal joint arthritis.

1. INTRODUCTION

Thumb basal joint (first carpometacarpal joint) arthritis is a common disabling condition, with a 10% lifetime prevalence.¹ It affects women over 45 years of age mostly, and approximately one-third of postmenopausal women.² Patients with mild arthritis respond well to conservative treatment. Surgical intervention is usually indicated in advanced stages and in those with failed conservative treatment. Several surgical techniques have been described, but no single surgical procedure has been proven to be superior to any other.³ Ligament reconstruction and tendon interposition (LRTI) is the most commonly used technique, and was first described by Burton and Pellegrini in 1986.⁴ This procedure combines the concept of volar ligament reconstruction proposed by Eaton and Littler and space interposition arthroplasty, as described by Froimson.⁵ We modified the procedures with a flexor carpi radialis (FCR) reloop around the insertion as an additional suspension, and reported the long-term outcomes of this modified LRTI procedure in treating thumb basal arthritis.

2. METHODS

The present study was conducted as a retrospective study of chart data, and informed consent was waived due to its retrospective nature. The degenerative condition of the basal joints were assessed radiologically using the Eaton and Littler staging system.^5,6 Between 1982 and 2004, 94 patients with 102 cases of thumb basal joint arthritis, stage III to IV, who underwent modified LRTI procedures, were evaluated. All the surgeries were performed by a single surgeon, who was classified as level 4 (a highly experienced specialist), according to Tang’s grading.⁷ Patients with bilateral basal joints involvement underwent operation at different times for each side, with at least 1 year in between.

2.1. Surgical techniques

We modified Burton’s ligament reconstruction and interposition arthroplasty.³ Based on the technique described by Wagner, we made a 2 to 3-cm skin incision. The encountered dorsal cutaneous branch of the radial nerve and the radial artery had to be protected. A longitudinal capsulotomy was performed just volar to the abductor pollicis longus (APL) tendon focus on the trapezium. The trapezium was excised with a rongeur after subperiosteally dissecting all soft tissue attachments to it. Care should be taken not to damage the FCR volarly. Also, any possibly impinged osteophyte on the base of the first and second metacarpal and on the trapezoid should be checked and removed, if necessary.

Then, the ulnar half-tendon slip of the FCR tendon was cut at the musculotendinous junction at the level of the mid-forearm, and the half-tendon slip was dissected and retracted with multiple transverse incisions on the volar forearm. The tendinous strip was passed into the trapezial space and dissected distally to the FCR insertion, as a distally-based tendon graft. With pronation of the thumb, a bony tunnel was made from 5 mm distally and ulno-dorsally to the APL tendon insertion to the articular surface of the thumb metacarpal base. The tunnel was enlarged with progressively larger gouges at both orifices. The harvested FCR tendon strip was passed through the tunnel and weaved with the APL tendon. Gentle traction was applied with the thumb in a neutral position, and the trapezial space was rechecked by fluoroscope. The tendon graft was tightened and fixed with 4-0 polypropylene (Prolene). The FCR tendon graft was passed back to the residual native FCR tendon closest to its insertion and fixed with 4-0 Prolene under tension. The residual FCR tendon graft was weaved and interposed into the trapezial space (Fig. 1). The thumb metacarpal was transfixed to the scaphoid with a 1.6-mm K-wire. The incised capsule of the trapezial space was repaired and then the skin was closed. A forearm-based thumb spica splint was applied.

Fig. 1.

Illustrations of modified ligament reconstruction and tendon interposition (LRTI) procedures: A, The distal-based half flexor carpi radialis tendon graft was passed through the bony tunnel of the first metacarpal base and fixed to the abductor pollicis longus tendon with suture. B, The tendon graft was routed back to loop its insertion and fixed with sutures, as a double suspensory ligament reconstruction. C, The remaining flexor carpi radialis graft was sewn into the trapezial space for interposition arthroplasty.

2.2. Postoperative follow-up and assessment

The stitches were removed 10 to 14 days after operation. The K-wire and thumb spica splint were removed 4 weeks after surgery, and then active range of motion exercises for the thumb were started. The thumb spica splint was used at night for an additional 4 weeks. Muscle strengthening and thumb motion exercises were started at 8 weeks after the operation.

Postoperative follow-up for each patient was arranged once every 2 weeks in the first month and once every month for two more months. Then, follow-up every 6 months was arranged. Additional visits were scheduled, if indicated. The radiographs were taken at every follow-up. All patients were evaluated by a project investigator, who was not involved in the treatment of the patients.

We evaluated the surgical outcomes in terms of subjective pain, clinical measurements, and radiographic findings. The frequency of pain was scaled as no pain, minimal, occasional, and frequent pain. Clinical measurements included power-grip strength, key pinch strength, and radial thumb abduction angle. Grip strength was evaluated using a Jamar dynamometer (Sammons Preston, Bolingbrook, IL, USA) set to the second position. A Jamar pinch gauge (Sammons Preston, Bolingbrook, IL, USA) was used to test key pinch by pressing the gauge between the pads of the thumb and the radial side of the index finger. The injured and uninjured hands were both tested three times, and the highest was taken. For the radiographic evaluation, we measured the change in height of the trapezial space (the distance between the distal articular surface of the scaphoid and the proximal articular surface of the first metacarpal) on routine anteroposterior views.⁸ The outcomes were grouped into one of the four categories, including excellent, good, fair, and poor, based on pain, joint stability, and key pinch strength. The worst of these three parameters was chosen for classifying (Table 1).

Table 1.

Grading of the outcomes

3. RESULTS

Ninety-one hands (84 patients: 52 female, 32 male) with full chart records and an average follow-up of 11.7 years (1-21.6 years) were included. The average age of the included patients at the time of surgery was 65.4 years (range, 48-84 years). Forty-two hands were graded as Eaton stage III basal joint arthritis and 49 hands as stage IV.

According to the functional classification in Table 1, 66 and 23 hands had excellent and good results, respectively (Tables 2 and 3). For most of the patients, they were satisfied with the pain relief. The average power-grip and key pinch strength were 32.4 Kg and 6.9 Kg, which equaled 97.5% and 93.3% of the contralateral hands, respectively. The average thumb radial abduction angle was 69.8°, which was 88.9% of the contralateral hands (Table 4). The mean diminution of the height of the trapezial space was 4.7 mm, with 4.2 mm (range, 1-8 mm) in the stage III group and 5.2 mm (range, 2-9 mm) in the stage IV group.

Table 2.

Functional results related to the osteoarthritic stages

Table 3.

Functional results related to different age

Table 4.

Clinical outcomes relative to osteoarthritic stages and percentage of the contralateral side

There were 68 hands had a follow-up period of more than 5 years, which was as many of 75% in our cases, with an average of 15.8 years (range, 5.2-21.6 years). Among them, 45 (66.2%) hands were reported to have had excellent results and 21 (30.9%) had good results.

There were no complications except superficial wound infection, which occurred in two hands (two patients). Both were cured after oral antibiotics treatment.

4. DISCUSSION

Arthritis of the basal joint is a common problem, particularly in postmenopausal females. Regarding gender distribution in our studies, there were more male patients than female patients enrolled. This might be due to the fact that a large percentage of the patients at our hospital were male veterans.

Trapeziectomy with an LRTI procedure provides stability for the first metacarpal through tendon grafting as ligament suspension, and creates a new joint in the trapezial space by tendon graft interpositioning.⁹ This is a more reasonable way of joint reconstruction than fusing the joint, and the reconstructed joint was reported to have better functional outcomes than basal joint arthrodesis.¹⁰ Our study showed similar good pain relief and functional outcomes to other studies.^9,11 But, our results provided more evidence of good outcomes over time.

Some other modified LRTI methods have been proposed, including those that choose different tendons, proceed through a bone tunnel or not, use sutures or an anchor method, or even hematoma distraction arthroplasty, and the short-term results were all good.^12–18 Ours is an easy method of modifying the traditional LRTI⁴ with a looping enforcement for ligament reconstruction and metacarpal suspension. Also, the looped tendon can serve as a part of the interposition. Long-term results with this modified LRTI procedure have been promising.

Some of the other surgical treatments, such as prosthesis arthroplasty, partial trapeziectomy with hematoma distraction arthroplasty or tendon interposition, would be good solutions for basal joint arthritis with a need to preserve the scaphotrapezial joint. But, if there are degenerative changes in the scaphotrapezial joint, the functional results will be compromised. In situations in which there is a concern about scaphotrapezial problems, LRTI could be a choice.

There has been no correlation between proximal metacarpal migration and pinch strength.^19,20 In our study, the decrease in height was similar to or even less than that reported in other studies,^16,21–24 and we could not find a correlation between decreased trapezial height and pinch/grip strength. Also, height did not correlate with functional staging, age, and severity of arthritis. Many factors that cannot be controlled in a retrospective study, mainly the work-characteristic and follow-up duration, would be of a large variety and may well have led to nonsignificant results. From the study results, we can see that the LRTI procedure would work well on its own, without too much concern about further proximal migration of the first metacarpal. We cannot compare our decreased height results with those of other reports to show a significant difference due to the different study designs, but we believe the additional simple looping procedure would be at least of no harm to the results and may possibly improve the results, compared to direct interposition with a long residual FCR tendon graft.

Patients with stage III arthritis had better power-grip strength, key pinch, and thumb abduction angle than patients with stage IV arthritis (Table 4). The radiologic results for patients with stage III arthritis also showed less height diminishment of the trapezial space than for patients with stage IV. Correlation analysis would be not appropriate in this study because of its retrospective nature and the long-term review, and that many important variables could not be included. But, we can see a trend in which stage III patients seem to have less trapezial space height diminishment and better surgical results. A greater severity of arthritis would lead to more long-term weakened functioning and more ligaments or tendon attenuation. It would be possible that patients with stage IV arthritis would have some decreased functional recovery from the greater and longer weakened status and have more trapezial space height diminishment, as the ligaments and tendons around the joint could be attenuated. But the functional outcomes were both good and satisfactory in stage III and IV arthritis patients after the modified LRTI procedures.

Only two patients had fair surgical results, and both of them were older than 80 years. Both of them had only 1 mm of proximal metacarpal migration in the final follow-up. Their poor results were related to pain and insufficient key pinch strength. This could be due to the period of immobilization, which would lead to stiffness and weakness, and that the older patients could have had more limited ability and less motivation for rehabilitation. Therefore, a more conservative or less invasive procedure with early rehabilitation would be a more suitable treatment strategy for these patients.^18,25,26

All of the patients aged between 40 and 80 years with advanced basal joint arthritis had excellent or good functional results. Trapeziometacarpal arthrodesis would be a choice for young patients, since better strength recovery could be expected.²⁷ But, the fused joint would lead to less motion of the thumb, and it was reported to have had more complications and less functional improvement.^28–30 Spekreijse et al reported that trapeziectomy with LRTI can achieve better pain reduction and functional outcome than trapeziometacarpal arthrodesis in women over 40 years with stages II to III basal joint osteoarthritis.¹⁰ So, we believe that the LRTI procedure could be a good and durable solution for patients with a wide range of age and who have advanced basal joint arthritis.

Our study had some limitations and mainly was due to the retrospective nature. Also, the sample size may not be large enough to reach conclusions with sufficient statistical power.

In conclusion, the modified LRTI procedure could achieve good stability and functional outcomes in treating thumb basal joint arthritis, even in young patients. The procedure yielded durable results and the complication rate was low.