Search

Category: Midfoot/Forefoot Introduction/Purpose: There are several treatments for hallux rigidus, including the use of a synthetic cartilage implant (SCI). Level I studies have shown success with these implants, but some patients do require conversion to arthrodesis for ongoing symptoms. The purpose of this radiographic review was to examine if baseline bone alignment, dimensions, and arthritis status are were different for patients who required conversion to arthrodesis compared to a control group with successful outcome. Methods: A radiographic review was conducted using data for from 15 hallux rigidus subjects implanted with an SCI enrolled in a during a previously concluded Level 1 clinical trial. Ten (10) Success subjects were identified as subjects those without conversion and with the lowest VAS pain levels indicating the most favorable outcome formed a success (control) group. Five (5) Conversion (study) subjects were identified as those with a conversion requiring revision to fusion and the with highest VAS scores indicating the least favorable outcome. Preoperative Weight-bearing AP and lateral radiographs from baseline visits were reviewed. Using previously validated Quantitative Motion Analysis software, two radiologists made the following measurements: first interphalangeal angle; first/second intermetatarsal angle; hallux valgus intraphalangeal angle; metatarsus adductus angle; metatarsal declination angle; first to second metatarsal length; functional ratio; and first metatarsal cortical thickness. Preoperative assessments of arthritis grade, metatarsalus primus elevatuselevation, sesamoid arthritis, and sesamoid station were also performed. Results: First metatarsal length was approximately 3% larger longer in the Conversion group compared to the Success group (85.2% vs. 82.5%). This was driven by the Conversion group having longer median normalized first metatarsal length (88.5% vs. 86.6%) and shorter median normalized second metatarsal lengths (104.0% vs. 106.3%). First metatarsal The second exception was cortical thickness was greater in the conversion group. This measurement was defined as the combined width of the medial and lateral cortices measured at the midline of the first metatarsal normalized to the full midline diameter of the first metatarsal. The median cortical thickness was almost 7% larger in the Conversion group compared to the Success group (40.1% vs. 33.2%). Nine Success subjects and 2 Conversion subjects had Grade 3 arthritis, while all other subjects had Grade 2. Three (60%) Conversion subjects and two (20%) Success subjects had evidence of metatarsus primus elevatus. Conclusion: Baseline joint alignment did not correlate with the need for conversion to arthrodesis. Conversion subjects had larger functional ratios longer first rays and greater cortical thickness. Published literature suggests smaller functional ratios result in increased second ray loading. It is possible the opposite is occurring in Conversion subjects, with longer first and shorter second metatarsal lengths resulting in increased loading of the SCI implant. The result indicates that shortening the first ray may be required to achieve a successful outcome with SCI. Success patients had a lower incidence of metatarsus primus elevatus.

Category: Ankle Arthritis Introduction/Purpose: Researchers and clinicians measuring outcomes following total ankle replacement (TAR) are challenged by the wide range of outcome measures used in the literature without consensus as to which are valid, reliable, and responsive in this population. This review identifies region- or joint-specific outcome measures used for evaluating TAR outcomes and synthesizes evidence for their measurement properties. Methods: A standard search strategy was conducted of electronic databases MEDLINE, EMBASE and CINAHL (to June 2015) to identify foot/ankle measures in use. A best evidence synthesis approach was taken to critically appraise measurement properties [COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN)] of identified measures. The review was restricted to English publications and excluded cross-cultural adaptations. Measurement properties collected from each article were coded for validity, reliability, responsiveness, or interpretability. Psychometric evidence exists for identified measures tested in non-TAR populations, but were not the focus of this review. Results: The search identified five measures to include in the best evidence synthesis, which have undergone psychometric testing in a TAR population (Foot Function Index, Ankle Osteoarthritis Scale, American Orthopaedic Foot and Ankle Society Ankle- Hindfoot Scale, Foot and Ankle Outcome Score, Self-Reported Foot and Ankle Score). Methodological quality of the studies providing psychometric evidence was assessed: (1) Validity—Two good quality studies examining different measures provide moderate evidence supporting construct validity (SEFAS; FFI, AOS, AOFAS *subjective items); (2) Reliability—two good quality studies examining different measures provide moderate evidence supporting internal consistency and test-retest reliability (FFI, AOS, AOFAS*; FAOS, SEFAS); (3) Responsiveness—one fair quality study provides limited evidence for AOFAS*, AOS, FFI; (4) Interpretability—two studies provided interpretability values (AOS, FFI, AOFAS*). Conclusion: This review offers a basis for choosing the most appropriate instrument for evaluating TAR outcomes. Numerous outcome measures were identified with evidence supporting their use in populations with various foot/ankle conditions, but none have strong evidence supporting usage in a TAR population. Outcome measures must have adequate psychometric properties in all patient groups in which they are applied. Evidence supporting or critiquing an instrument should not be based on studies with poor quality methodology, as identified by this review. Further testing in a TAR population would benefit identified measures with emphasis on adequate sample sizes, testing a priori hypotheses, and evaluating their content validity for a TAR population.

Category: Midfoot/Forefoot Introduction/Purpose: Hallux rigidus is the most common arthritic condition of the foot. A prospective, randomized, non-inferiority clinical trial of first metatarsophalangeal joint (MTPJ) hemiarthroplasty with a synthetic polyvinyl alcohol hydrogel implant, for moderate to severe hallux rigidus, demonstrated maintenance of MTPJ active dorsiflexion motion and excellent pain relief; additionally, the trial showed functional outcomes and safety equivalent to first MTPJ arthrodesis at 24 months (Baumhauer et al. 2016; FAI:37(5):457-469). Recognizing that many hemiarthroplasty and total toe implants have initially good results that deteriorate over time, the purpose of this study was to prospectively assess the safety and efficacy outcomes for the synthetic cartilage implant population and to determine if the excellent outcomes were maintained at >5 years. Methods: One hundred and fifty-two patients underwent implant hemiarthroplasty in the original trial; 14 underwent implant removal and conversion to fusion and 3 were lost to follow-up during the first 24 months, leaving 135 eligible for this study. One hundred patients were evaluated at 5+ years; 5 could not be reached for follow-up. Thirty are pending consent, follow-up, and/or data entry; their status will be available for inclusion at the conference presentation. Patients completed a pain visual analogue scale (VAS) and Foot and Ankle Ability Measure (FAAM) Sports and Activities of Daily Living (ADL) scores, preoperatively and at 2, 6, 12, 26, 52, 104 and 260 weeks postoperatively. Minimal clinically important differences are: =30% difference for pain VAS, 9 points for FAAM Sports, and 8 points for FAAM ADL. Great toe active dorsiflexion, weight-bearing radiographs, secondary procedures, and safety parameters were evaluated. Results: Of 100 synthetic cartilage implant hemiarthroplasty patients available at mean 5.8 years follow-up (SD ±0.7; range: 4.4- 7.4), 5 underwent implant removal and conversion to fusion in years 2-5 (Figure 1), and 2 underwent subsequent surgical interventions during the pivotal trial and were censored, leaving 93 patients for evaluation. Pain and function outcomes observed at 5.8 years were similar to those at 2 years (Figure 1). VAS Pain and FAAM Sports Scores were maintained or improved at 5.8 years follow-up, but these differences were not clinically significant. Joint motion was maintained at 5.8 years. No evidence of avascular necrosis, device migration or fragmentation was observed upon independent radiographic review. Eighty-six percent of patients agreed their overall well-being had improved, and 92% would have the procedure again. Conclusion: Clinical and safety outcomes of patients having undergone synthetic cartilage implant hemiarthroplasty for the surgical treatment of hallux rigidus were previously demonstrated to be non-inferior to the gold standard treatment, MTPJ fusion, at 2 years. Prospectively determined outcomes for 100/135 of these implant hemiarthroplasty patients at 5.8 years are similar to those reported at 2 years. Longer-term results demonstrate that clinical and safety outcomes for synthetic cartilage implant hemiarthroplasty are durable, and that the implant remains a viable treatment option to decrease pain, improve function and maintain motion for advanced hallux rigidus.