Clinical and Radiologic Outcomes of Metatarsophalangeal Hemiarthroplasty

Clinical and Radiologic Outcomes of Metatarsophalangeal Hemiarthroplasty

Clinical and Radiologic Outcomes of Metatarsophalangeal Hemiarthroplasty: A Review of 12 Consecutive Cases
Florian Wanivenhaus, MD; Jacqueline Fust, MD; Matthias Erschbamer, MD, PhD; Andreas Schirm, MD
Orthopedics. 2018;41(1):e64-e69
Abstract
Abstract
This study examined function, pain, satisfaction, and radiologic outcomes among patients treated with first metatarsophalangeal hemiarthroplasty. Patients were invited to participate in an outcome study conducted with questionnaires on subjective and objective outcomes and clinical and radiographic follow-up. A total of 12 patients (12 feet; mean patient age, 58.8±12.3 years) agreed to participate. Mean follow-up was 22.3±19.8 months. Of these patients, 7 were satisfied with the postoperative result. The mean visual analog scale pain score decreased significantly from 7.0±2.3 preoperatively to 3.5±3.3 postoperatively (P=.024). Mean passive range of motion of the first metatarsophalangeal joint was 32°±10° preoperatively, 93°±18° intraoperatively after implantation of the prosthesis and closure of the joint capsule, and 38°±19° at final follow-up (P=.26). Mean American Orthopaedic Foot and Ankle Society forefoot score increased significantly from 47.3±14.7 preoperatively to 71.8±15.2 at last follow-up (P=.033). During the follow-up period, 6 patients underwent additional procedures: 5 therapeutic joint infiltrations and 1 arthrodesis. No patients had radiologic loosening of the implant at final follow-up. Osseous dysplastic changes at the base of the proximal phalanx were noted among 6 of 11 patients (12 total cases) at final follow-up. Although first metatarsophalangeal hemiarthroplasty provided significant pain reduction at mean follow-up of 22.3 months, range of motion of the first metatarsophalangeal joint was not restored to anticipated levels and there were high rates of patient dissatisfaction and secondary interventions. [Orthopedics. 2018; 41(1):e64–e69.]
Full Text
Abstract
This study examined function, pain, satisfaction, and radiologic outcomes among patients treated with first metatarsophalangeal hemiarthroplasty. Patients were invited to participate in an outcome study conducted with questionnaires on subjective and objective outcomes and clinical and radiographic follow-up. A total of 12 patients (12 feet; mean patient age, 58.8±12.3 years) agreed to participate. Mean follow-up was 22.3±19.8 months. Of these patients, 7 were satisfied with the postoperative result. The mean visual analog scale pain score decreased significantly from 7.0±2.3 preoperatively to 3.5±3.3 postoperatively (P=.024). Mean passive range of motion of the first metatarsophalangeal joint was 32°±10° preoperatively, 93°±18° intraoperatively after implantation of the prosthesis and closure of the joint capsule, and 38°±19° at final follow-up (P=.26). Mean American Orthopaedic Foot and Ankle Society forefoot score increased significantly from 47.3±14.7 preoperatively to 71.8±15.2 at last follow-up (P=.033). During the follow-up period, 6 patients underwent additional procedures: 5 therapeutic joint infiltrations and 1 arthrodesis. No patients had radiologic loosening of the implant at final follow-up. Osseous dysplastic changes at the base of the proximal phalanx were noted among 6 of 11 patients (12 total cases) at final follow-up. Although first metatarsophalangeal hemiarthroplasty provided significant pain reduction at mean follow-up of 22.3 months, range of motion of the first metatarsophalangeal joint was not restored to anticipated levels and there were high rates of patient dissatisfaction and secondary interventions. [Orthopedics. 2018; 41(1):e64–e69.]
Osteoarthritis of the first metatarsophalangeal joint, referred to as hallux rigidus, inhibits weight transfer and adequate first metatarsophalangeal flexion force to aid toe-off during gait. 1 Loss of first metatarsophalangeal joint motion can interfere with activities that require extensive toe motion, such as running and jumping, and may affect the choice of footwear. Arthrodesis has remained the gold standard procedure for the treatment of end-stage hallux rigidus. Driven by patient requests for reliable pain relief while preserving a mobile first metatarsophalangeal joint, several prosthetic designs have been developed.
Prosthetic designs and surgical techniques have advanced from early silicone implants that showed high rates of wear, osteolysis, and foreign body reactions. 2 However, although some current first metatarsophalangeal total joint prosthetic designs have shown good short-term clinical outcomes, they have been associated with a high rate of aseptic loosening at midterm follow-up. 3,4 Additional complications include soft tissue instability of the joint, transfer metatarsalgia, and substantial bone loss. 5 Hemiarthroplasty by means of resurfacing of the damaged articular surface of the first metatarsal head has shown promising results. 6–8 The advantage of hemiarthroplasty over total arthroplasty is the decreased amount of bone resection necessary, thus maintaining sufficient bone stock for fusion if needed. 7 The current retrospective study evaluated the authors' experience with hemiarthroplasty of the first metatarsophalangeal joint using a metatarsal head resurfacing prosthesis and compared the results with findings reported in the literature.
The objectives of this study were to (1) determine the degree of postoperative pain relief; (2) evaluate functional outcomes and patient satisfaction; (3) determine the rate of secondary interventions; and (4) analyze radiographic alignment, osseous changes in the proximal phalangeal base, and implant loosening.
Materials and Methods
The ethics committee at the study institution approved this retrospective study, and all participants provided written informed consent.
The authors identified all patients who underwent first metatarsophalangeal hemiarthroplasty at their study institution from January 2011 to February 2016. Included in the study were all patients who underwent hemiarthroplasty of the first metatarsophalangeal joint with a metatarsal head resurfacing implant (HemiCAP; Arthrosurface Inc, Franklin, Massachusetts). The indication for hemiarthroplasty of the first metatarsophalangeal joint was a painful joint with advanced arthritic changes and no response to conservative measures but without degenerative sesamoid arthritis. The authors excluded all patients who had undergone an additional procedure at the time of the first metatarsophalangeal hemiarthroplasty implantation. Data collected included the following demographic factors: sex, age, body mass index, surgical indications, and previous hallux surgery. The score on the hallux metatarsophalangeal–interphalangeal scale of the American Orthopaedic Foot and Ankle Society (AOFAS) was recorded preoperatively and at last follow-up. Patients rated their pain on a visual analog scale ranging from 0 (no pain) to 10 (maximal pain) points before surgery and at final follow-up. For all patients, passive flexion, extension, and total range of motion were measured with a standard goniometer preoperatively, intraoperatively after implantation of the prosthesis and closure of the joint capsule, at 6-week follow-up, at 3-month follow-up, and at final follow-up. All patients rated their postoperative level of athletic activity compared with their preoperative level, and all patients indicated their level of satisfaction with the procedure.
Radiologic Assessment
Radiographic assessment included standard dorsoplantar, oblique, and lateral weight-bearing radiographs obtained preoperatively and postoperatively to determine the hallux valgus angle, intermetatarsal 1–2 angle, and dorsiflexion angle of the hallux. The hallux valgus angle was defined as the intersection of the longitudinal bisection of the first metatarsal and the first proximal phalanx. The intermetatarsal 1–2 angle was defined as the intersection of the longitudinal bisection of the first and second metatarsal shafts. The dorsiflexion angle, with reference points placed at the midpoint of the proximal and distal aspects of the diaphyses of the proximal phalanx and first metatarsal, was measured on lateral radiographs. Degenerative changes in the first metatarsophalangeal joint were graded (grades I–III) as described by Hattrup and Johnson. 9 This grading system, developed for radiographic grading of hallux rigidus, is based on increasing osteophyte production, joint space narrowing, and subchondral sclerosis. 6 The bone–implant interface was classified as normal or lucent, based on the most recent postoperative standard weight-bearing radiographs. Osseous changes of the base of the proximal phalanx also were noted on postoperative radiographs.
Surgical Technique
All surgical procedures were performed by the senior author (A.S.). The patient was placed in the supine position on the operating table, with a tourniquet placed on the thigh. The tourniquet was adjusted to 300 mm Hg. Preoperatively, all patients received a second-generation cephalosporin antibiotic. The first metatarsophalangeal joint was approached through a dorsomedial skin incision. The extensor hallucis tendon was retracted laterally during the entire procedure. The lateral and medial collateral ligaments and the plantar plate were released to allow full exposure of the joint. A drill guide was used to insert a Kirschner wire into the center of the first metatarsal, in line with the midline axis of the shaft. Fluoroscopy was performed to verify that the wire was positioned adequately in the sagittal and coronal planes. A step drill was inserted over the guidewire, and the metatarsal head was drilled until the proximal shoulder of the drill was flush with the plantar articular surface of the metatarsal head. The hole was tapped, and a taper post was inserted over the guidewire until the line on the driver was flush with the plantar articular surface of the metatarsal head. The articular geometry of the metatarsal head was checked with mapping measuring guides, and the final size of the implant was determined. The appropriate implant was chosen, and the metatarsal head was resurfaced to match the shape of the implant. After the capsule was closed, range of motion of the first metatarsophalangeal joint was documented.
Patients were allowed to ambulate while wearing a stiff-soled postoperative shoe under full weight bearing for 6 weeks. They were instructed to perform passive range of motion exercises of the great toe.
Statistical Analysis
Statistical analysis was performed with R software (R Foundation for Statistical Computing, Vienna, Austria). Differences in visual analog scale score, AOFAS fore-foot score, radiographic alignment, and range of motion were determined with the Wilcoxon signed rank test. Statistical significance was defined as P