1. John Peter Smith Hospital
LONG-TERM FOLLOW UP OF METATARSAL HEAD RESURFACING IMPLANTS FOR HALLUX RIGIDUS
Chief Resident, John Peter Smith Hospital, Department of Orthopaedic Surgery, Fort Worth, Texas
Associate Professor, University of North Texas Health Science Center, John Peter Smith Hospital, Department of Orthopaedics, Fort Worth, Texas
John Peter Smith Hospital
Henry Hilario, DPM1; Brian Carpenter, DPM2; Alan Garrett, DPM2; Travis Motley, DPM2
FIGURE 1. (A)Hallux Rigidus X-ray (B) HemiCAP Implant (C) Post-Op X-ray
Introduction:
Hallux rigidus describes a painful condition that affects the great toe at the metatarsophalangeal joint (MPJ). Symptoms can include a limited dorsiflexion of the joint, painful range of motion, and proliferative bone formation. Hallux rigidus is similar to other arthritic conditions and results in a stiff and painful joint that can become progressively worse. Pain is believed to be caused by shearing forces at the arthritic joint. The attempted motion at the joint is restricted by periarticular spurring. This pain can range anywhere from occasional to severe and debilitating during any activity. Hallux rigidus can result in radiographic changes as well, including osteophyte formation, loose bodies, subchondral sclerosis, flattening of the metatarsal head and joint space narrowing1 (Fig 1a).
Treatment for hallux rigidus varies depending on disease severity, age and physical demands of the patient. There are several treatment options that have been reported in the literature. There is general agreement that cheilectomies of the MPJ or corrective osteotomies are effective at treating early and intermediate-staged hallux rigidus. Arthrodesis or arthroplasty of the MPJ is generally reserved for more severe arthritis2.
The area of controversy lies in which of the two options, arthroplasty or arthrodesis, is best for patients’ demands, activities and pain levels. Arthrodesis has been long touted as the “gold-standard” for its reliability and longevity, but is not without difficulties such as transfer metatarsalgia, shoewear limitations, malunion or nonunion3,4. In regards to arthroplasty, there are several permutations of constructs. Total arthroplasty, is comprised of various materials including silicone or metal at both sides of the joint. There is also hemiarthroplasty that addresses either the proximal phalanx or the metatarsal head.
The HemiCAP system (Arthrosurface Inc, Franklin, MA, USA) allows for resurfacing of the metatarsal head with implantation of a metallic articular cap (Fig 1b,c). The implant allows for minimal bone resection of the joint and does not interfere with the intrinsic muscle insertions of the proximal phalanx. Several studies over the past ten years have investigated hemiarthroplasty with the HemiCAP implant as an effective treatment for severe hallux rigidus. These investigations have looked at short-term and medium-term clinical results with favorable outcomes5-9.
To date, there have been no studies examining the long-term results of patients that undergo hemiarthroplasty of the metatarsal with a resurfacing implant. Previous studies have shown promising results with short and mid-term follow ups. The purpose of our retrospective study was to investigate the long-term outcomes of patients who have undergone hemiarthroplasty with the HemiCAP implant.
Methods:
Selection criteria for our study consisted of patients who underwent MPJ hemiarthroplasty with the HemiCAP implant between March 2002 and January These patients presented to the clinics of the senior authors (B.C., A.G. and T.M.) This range was selected to give us an average follow up of about ten years. Inclusion criteria included those found to have Grade II (moderate osteophytes with joint space narrowing and subchondral sclerosis) or Grade III (marked osteophytes, loss of joint space, and possible subchondral cysts) hallux rigidus according to the Hattrup and Johnson classification system10. All surgical procedures were performed by the three senior authors. Patients were assessed by the American Orthopaedic Foot & Ankle Society (AOFAS) clinical rating system for the hallux. The AOFAS system is used to evaluate the condition of the first metatarsophalangeal and interphalangeal joints 11 .
Final follow-up was conducted by the resident or attending surgeon via telephone. This included their AOFAS score and patient satisfaction survey that comprised of following questions: “Based on your experience, would you undergo this procedure again?,” “Have you needed repeat surgery to the affected toe,” and “How often do you need pain medication for your toe?”
With our inclusion criteria for this study we were also able to contact the patients included in the previous study by Carpenter et al. in 2010 that looked at AOFAS scores in the mid-term and included pre-operative AOFAS scores6. The surgery for implantation was performed as written in manufacturer’s protocol.
Table 1. Means of long-term AOFAS scores.
Table 2. Comparison of mid-term scores to long-term scores using data from Carpenter et al. study in 2010
Table 1
Mean SD
1. Pain (40)
37.8
4.7
2. Function (45)
38.6
- Activity (10)
9.3
1.3
- Footwear (10)
7.7
2.5
- MPJ Range of Motion (10)
7.1
2.7
- IPJ Range of Motion (5)
4.6
1.4
- Stability (5)
5.0
0.0
- Callous present (5)
3. Alignment (15)
14.2
2.2
TOTAL AOFAS SCORE (100)
90.6
7.6
Table 2
Mean AOFAS SD
2010 Pre-Op
30.84
11.64
2010 Mid-term
89.16
7.5
2016 Long-term
89.97
8.13
Difference between 2010 and 2016
0.81
8.65
Metatarsal head resurfacing was performed on 56 patients between 2002 and Including the bilateral cases we were able to conduct the survey on a total of 45 implants (76.3%). This was comprised of 16 males and 29 females. The average age of patients on the date of surgery was 57.4 years old (range years) with most patients’ age between 50 and 70 years old. The average follow up was months (9.6 years) with a range, months. Long-term was defined as approximately 10 years and mid-term was defined as five years.
The mean overall AOFAS score at the long-term follow up was 90.6 (SD=7.6). The most common deduction in scores was due to decreased ROM. Fifty-eight of the 59 HemiCAPs remain implanted. Two of the 59 patients have undergone repeat surgery to the same joint. The one patient that underwent elective removal of the HemiCAP for continued joint pain did relate history of chronic pain issues at final follow-up. This patient underwent fusion of the joint, with subsequent procedure for removal of painful; hardware for her joint fusion. The other patient that was reoperated on underwent resection of dorsal spurs and would repeat HemiCAP procedure if needed. With the exception of the patient that underwent the fusion, the remainder of patients stated they would undergo the procedure again if needed. When looking at pain medicine requirements, 38 patients stated they have not taken any pain medication for their toe in many years. Seven patients stated they will rarely take ibuprofen or Tylenol less than once a month for their MPJ pain. Results are summarized in Table 1.
The inclusion criteria of this study also included the patients of the study by Carpenter et al. in 2010 at the same institution. That study included 32 patients that underwent the same procedure and looked at pre-op and mid-term AOFAS scores. The mean overall AOFAS score of this subset of patients at final follow-up was (SD=8.13). By using a t-test of means from this study versus the study in 2010, the p value was greater than 0.05 showing no significant change in AOFAS scores from the mid-term follow up. Results are summarized in Table 2.
Results:
Discussion:
Surgical treatment of late-stage hallux rigidus will continue to be a subject of debate. Our results in this investigation support hemiarthroplasty of the metatarsal with the HemiCAP implant. Patients in our study had high mean AOFAS scores after long-term follow up. Our data shows no difference in scores between mid-term and long-term results. The data also supports a very low reoperation rate with no serious complications. While fusions do have a reputation as the “gold-standard,” they are not without their challenges and can lead to patient dissatisfaction. There can be limitations of shoewear, activity modifications, malunion or nonunion of the fusion site, metatarsalgia, and painful hardware. The loss of motion at the joint can be an issue for occupations with kneeling/squatting, runners, and women with high heels.
Our data also shows better outcomes than hemiarthroplasty with proximal phalanx implants. The problems with the proximal phalanx implants are well documented with stiffness, continued pain and prosthetic loosening. It is possible that the shear stress of the proximal phalanx on the pathologic metatarsal head with repeated dorsiflexion can contribute to this loosening. The HemiCAP resurfacing system focuses treatment on the metatarsal side of the joint, where the majority of the pathology of hallux rigidus resides.
One limitation of our study is that we were only able to contact 76% of the patients. With the longer-term follow up comes the increased difficulties as patients move and change address and numbers. Another limitation was that final follow-up was conducted via telephone. We found difficulty in scheduling patients to return to the clinic for personal evaluation after 10 years post-op, especially as most were doing very well without any difficulties.
In conclusion, in the surgical treatment of late-stage hallux rigidus, the metatarsal head resurfacing implant is a safe and effective treatment that has lead to excellent outcomes after long-term follow up. A
References:
Coughlin, MJ, Shurnas, MD. Hallux Valgus: Demographics, Etiology, and Radiographic Assessment. Foot Ankle Int 28.7: , 2003.
Maffulli, N., et al. Quantitative review of operative management of hallux rigidus. British medical bulletin, 98(1), pp.75-98, 2011.
Brage, ME. et al. Surgical options for salvage of end-stage hallux rigidus. Foot and ankle clinics 7.1: 49-73, 2002.
Giannini, S et al. "What's new in surgical options for hallux rigidus?."The Journal of Bone & Joint Surgery 86.suppl 2: 72-83, 2004.
Hasselman, C.T. and Shields, N., Resurfacing of the first metatarsal head in the treatment of hallux rigidus. Techniques in Foot & Ankle Surgery,7(1), pp.31-40, 2008.
Carpenter, B., Smith, J., Motley, T. and Garrett, A. Surgical treatment of hallux rigidus using a metatarsal head resurfacing implant: mid-term follow-up. Journal Foot Ankle Surg: 49(4), pp , 2010.
Kline, AJ, and Hasselman, CT. Metatarsal head resurfacing for advanced hallux rigidus. Foot & ankle international, 2013.
Erdil, Mehmet, et al. Comparison of arthrodesis, resurfacing hemiarthroplasty, and total joint replacement in the treatment of advanced hallux rigidus. J Foot Ankle Surg 52.5: , 2013.
Meric, G, et al. Short-Term Clinical Outcomes After First Metatarsal Head Resurfacing Hemiarthroplasty for Late Stage Hallux Rigidus. J Foot Ankle Surg. 54: , 2015.
Hattrup, SJ et al. Subjective results of hallux rigidus following treatment with cheilectomy. Clinical orthopaedics and related research, 226, pp , 1988.
Kitaoka, HB et al. "Clinical rating systems for the ankle-hindfoot, midfoot, hallux, and lesser toes." Foot & Ankle International 15.7 : 1994.
ACKNOLOWEDGEMENTS: We would like to thank Victor Kosmopoulos, PhD for his assistance with our statistical analysis A B C