Abstract
Background:
Capsular interposition arthroplasty is a joint- and motion-sparing procedure that has been shown as an effective alternative to fusion. This study aimed to evaluate patient function and satisfaction after long-term follow-up.
Methods:
Sixty-four patients were treated with capsular interposition arthroplasty for hallux rigidus by the senior author performed between February 1998 and July 2011. Twenty-two patients could not be reached for follow-up and were thus excluded from the analysis. Therefore, 42 remaining patients were evaluated using the visual analog scale (VAS), Foot Function Index (FFI), Short Form 12 (SF-12), and patient satisfaction scores. The mean follow-up was 11.3 (range, 4-16) years.
Results:
The mean VAS for pain was 7.9 preoperatively and 1.8 postoperatively (P = .003). The mean preoperative SF-12 physical score was 42.0 vs 64.2 postoperatively (P = .02). The mean preoperative SF-12 mental score was 50.7, while the postoperative SF-12 mental score was 54.6 (P = .01). The total FFI score also significantly improved, with a preoperative value of 98.3 and a postoperative mean score of 49.6 (P = .001). The mean patient satisfaction score was 7.4 of 10. Overall, 39 of 42 patients (92.9%) stated they would have the surgery again. Four of the 42 patients (9.5%) required conversion to hallux metatarsophalangeal fusion at a mean of 6.1 years after the index procedure secondary to pain, but no other complications were reported.
Conclusion:
Capsular interposition arthroplasty was a safe and effective treatment for severe hallux rigidus. These longer term results demonstrate a high level of patient satisfaction.
Level of Evidence:
Level IV, retrospective case series.
Keywords
Arthritis or impingement of the first metatarsophalangeal (MTP) joint, also known as hallux rigidus, is a painful condition that can have a significant impact on quality of life. Hallux rigidus often presents with reduced range of motion at the MTP joint, especially in dorsiflexion. The severity of the condition is established through clinical and radiographic evaluation. 6 Initial treatment options include nonoperative management such as using rigid insoles/turf toe plates, nonsteroidal anti-inflammatory drugs (NSAIDs), intra-articular steroid injections, and activity modification. 14 If nonoperative modalities fail, surgery may be considered. There is extensive literature documenting successful treatment with dorsal cheilectomy of the metatarsal head with or without a Moberg osteotomy for early stages of the disease process.7,8,17,19 Advanced stages require more extensive procedures, such as resection arthroplasty, MTP fusion, interposition arthroplasty, total joint replacement, or, more recently, synthetic cartilage replacement.2,4,6,9,18,19 However, sacrificing range of motion of the hallux MTP joint is not always well accepted by patients, particularly those who are more physically active and who require range of motion such as dancers, athletes, and those who practice yoga.
The use of interposition arthroplasty of the first MTP joint was introduced several years ago as an alternative to joint-sacrificing procedures. Hamilton et al, 11 in one of the earliest reports of the procedure, described a standard dorsal cheilectomy with resection of the dorsal one-third of the metatarsal head, less than one-fourth resection of the proximal phalanx, and subsequent interposition of the extensor digitorum brevis tendon and the hypertrophied dorsal capsule into the joint, secured by suturing to the plantar plate. Subsequent studies have modified this technique by interposing human dermal collagen matrix or medial capsule rather than the dorsal capsule.3,10,12 Recently, a large retrospective case series by Aynardi et al 1 demonstrated promising results for interposition arthroplasty using either dermal matrix or capsule. Prior to this recent study, most studies were performed on relatively small cohorts with short- or medium-term follow-up.5,13,15,16,20,21,22,23
The aim of the present study was to retrospectively assess longer term outcome of hallux interposition arthroplasty performed by the senior author.
Methods
Inclusion criteria included patients affected by Coughlin and Shurnas grades 3 and 4 osteoarthritis of the hallux MTP joint that failed at least 6 months of nonoperative treatment. 6 Exclusion criteria included follow-up of less than 3 years, previous surgeries of the hallux MTP joint, diabetes, and rheumatoid arthritis.
The authors identified 64 patients treated with interposition arthroplasty for hallux rigidus performed between February 1998 and July 2011 by the senior author. Patients completed questionnaires through either email or mail. Twenty-two patients did not respond to the questionnaires or could not be contacted by phone or mail. Therefore, a total of 42 patients were included in this retrospective review. There were 34 women (81%) and 8 men (19%). Mean age at surgery was 64 years (range, 51-82 years). The mean follow-up was 11.3 years (range, 4-16 years). All charts were reviewed to collect preoperative scores, including the visual analog scale (VAS) for pain, the Short Form 12 (SF-12), and the Foot Function Index (FFI). At final follow-up, all patients were once again asked to submit VAS, SF-12, and FFI surveys, as well as rating their satisfaction with the procedure (1 being not satisfied at all and 10 being extremely satisfied), whether they would have the procedure again (yes/no), and whether further hallux surgery had been necessary due to insufficient resolution of symptoms. The Student t test was used to compare the findings for the preoperative and postoperative pain and outcome scores with a P value of .05 considered significant. SPSS was used for statistical analysis (SPSS, Inc, an IBM Company, Chicago, IL).
Operative Technique
The incision was made dorsally and the extensor hallucis brevis tendon was then retracted and a transverse cut was made in the periosteum, capsule, and extensor brevis tendon 2 cm proximal to the metatarsophalangeal joint.
This entire soft tissue flap was raised in a U-shape, with a distal base that remained attached to the base of the proximal phalanx. The soft tissue was slightly elevated off the base of the proximal phalanx and then retracted distally to facilitate exposure for the phalangeal cut. The attachment of the flexor hallucis brevis was maintained by resecting less than 8 mm of bone on the plantar surface of the proximal phalanx. In addition, the cut was angled dorsally by 10 degrees so as to maintain a slightly elevated position of the hallux off the floor. The metatarsal head was cut with a saw, with the cuts contoured to maintain a circular shape of the head. Depending on the extent of arthrosis, 4 to 6 mm of bone was removed from the dorsal metatarsal head (Figure 1).
(A) Retraction of extensor hallucis longus tendon to expose the soft tissue flap with outline of area used for interposition. (B) Remove approximately 4 to 6 mm of the dorsal metatarsal head, and resect the base of the proximal phalanx at a slight angle to remove a dorsally based wedge of bone, without disrupting the distal insertion of the plantar plate. (C) Interposition of the soft tissue flap by passing sutures through the flap and drill holes and tying dorsally over the metatarsal bone.
Two 1.8-mm K-wire holes were drilled into the distal metatarsal head in an oblique fashion, roughly 1 cm proximal to the joint. These drill holes were obliquely oriented from dorsolateral to plantarmedial and dorsomedial to plantarlateral. We then used a 2-0 nonabsorbable suture to capture the flap. We then pulled the sutures through the K-wire holes from plantar to dorsal. The flap was then appropriately tensioned and the sutures were tied over the dorsal surface of the metatarsal head. The skin was closed in layers (Figures 2-5).
Preoperative anteroposterior radiograph of the right foot.
Preoperative lateral radiograph of the right foot.
Postoperative anteroposterior radiograph of the right foot.
Postoperative lateral radiograph of the right foot.
Postoperative Protocol
The postoperative protocol included early passive range-of-motion exercise. Patients were allowed to bear weight immediately in a flat postoperative shoe, and after 1 week they started with a program to maintain and improve the range of motion. The operative sandal was worn for 4 weeks but not longer.
Results
The mean VAS for pain was 7.9 (range, 6-10) preoperatively and 1.8 (range, 0-6) postoperatively (P = .003). The mean preoperative SF-12 physical score was 42.0 (range, 26-60) vs 64.2 postoperatively (range, 34-81) (P = .02). The mean preoperative SF-12 mental score was 50.7 (range, 35-65), while the postoperative SF-12 mental score was 54.6 (range, 42-69) (P = .01). The total FFI score also significantly improved, with a preoperative value of 98.3 (range, 49-130) and a postoperative mean score of 49.6 (range, 17-105) (P = .001).
Patient satisfaction was also reported, with a mean score of 7.4 (range, 3-10). Overall, 39 of 42 patients (92.9%) stated they would have the surgery again. Four of the 42 patients (9.5%) required conversion to hallux MTP fusion at a mean of 6.1 years (range, 4-9 years) after the index procedure secondary to pain. There were no other complications reported (Table 1).
Mean Preoperative and Postoperative Outcome Scores Using the VAS, SF-12, and Revised FFI Scores.
Abbreviations: FFI-A, Foot Function Index—Activity Limitations; FFI-D, Foot Function Index—Difficulty; FFI-P, Foot Function Index—Pain; FFI-S, Foot Function Index—Stiffness; FFI-SI, Foot Function Index—Social Issues; SF-12, Short Form 12; VAS, visual analog scale.
Discussion
Hallux interposition arthroplasty represents a joint-sparing procedure that minimally sacrifices bone stock. In the present study, statistically significant improvement was observed for all functional scores. At a mean of 6.1 years, only 9.5% of patients required conversion to fusion. Previous studies have had similarly excellent results in functional outcome scores. Johnson and McCormick 13 reported a significantly better postoperative American Orthopaedic Foot & Ankle Society (AOFAS) score compared with hallux MTP arthrodesis in their cohort of 10 patients. Mroczek and Miller 20 described a similar technique and stated excellent results, although anecdotally.
Berlet et al 3 described a modified Keller arthroplasty in 9 patients using a human dermal collagen matrix. The patients demonstrated improved pain scores postoperatively, as well as good alignment and function. The same authors published a 5-year follow-up study on 6 of the 9 original patients demonstrating continued excellent AOFAS scores, without any subsequent need for revision MTP fusion.3,12
Hahn et al 10 described a modification of capsular interposition arthroplasty using the medial capsule rather than the dorsal capsule and the extensor hallucis brevis tendon. They investigated a cohort of 22 patients with severe hallux rigidus at a mean of 24 months. The authors observed excellent postoperative AOFAS MTP–interphalangeal (IP) and SF-36 scores.
Most recently, Aynardi et al 1 conducted a large retrospective case series analyzing 133 patients. They used either a modified oblique Keller interposition arthroplasty or allograft in the form of acellular dermal matrix. The authors did not find any difference between these 2 different treatments. This group found similarly significant decreases in VAS and FFI scoring. The authors reported a failure rate of 3.8%, and their average time to failure was 8.8 months. Our cohort had a slightly higher rate of revision surgery, but our time to failure was much greater. In addition, their group reported several complications not seen in our cohort, such as infection (1.5%), cock-up deformity of the first MTP joint (4.5%), and metatarsalgia of the second or third MTP joint (17.3%). The use of a dermal acellular matrix may be advantageous in patients who lack a thick capsule, but it is associated with increased cost. Overall, both of our cohorts demonstrated promising results and further strengthened the case for interposition arthroplasty in treating severe stages of hallux rigidus.
Limitations of this study include the lack of final follow-up radiographs, the lack of a control group, and the retrospective nature of the study. In addition, we did not compare preoperative and postoperative range of motion of the first MTP joint. We also had 34.4% of patients who did not respond to our survey. This could be due to a number of issues, related to the long-term and retrospective nature of the study. In some cases, patients were not contacted for over 15 years since their surgery. It is possible that many patients may have changed their contact information since surgery. Also, patients who were dissatisfied with their care may have changed surgeons or simply declined to respond. This could have resulted in the high attrition rate and possible underreporting of complications.
In conclusion, to our knowledge, this study represents the longest mean follow-up for a cohort of patients treated with hallux interposition arthroplasty for end-stage osteoarthritis. Although this study had a high attrition rate, it demonstrates that interposition arthroplasty could provide long-term improvement in symptoms associated with grade 3 and 4 hallux rigidus.
Footnotes
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. ICMJE forms for all authors are available online.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
References
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