ABSTRACT
BACKGROUND: Ex vivo studies have established that arrow fixation of meniscal tears is inferior to vertical sutures and is dependent on arrow length, although the influence of tear location is not known. HYPOTHESIS: Arrow length and tear location influence the mechanical properties of meniscal arrows. STUDY DESIGN: Controlled laboratory study. METHODS: A longitudinal incision was created either 2 mm or 7 mm from the periphery in 70 bovine medial menisci. Each was repaired with a meniscal arrow (10, 13, or 16 mm) or a single vertical suture and subjected to load-to-failure testing and video-graphic analysis. RESULTS: Mode of failure (P <.0001), maximum force (P <.0001), stiffness (P <.01), 2-mm gap force (P <.03), and ultimate gap formation (P <.002) were all directly related to arrow length. Sixteen-mm arrows and suture exhibited similar, superior mechanical properties. Tear location significantly influenced properties of 10-mm and 16-mm but not 13-mm arrows. Ten-millimeter arrows displayed the worst performance. CONCLUSIONS: Mechanical properties of meniscal arrows depend on tear location and arrow length. CLINICAL RELEVANCE: Sixteen-millimeter arrows are a possible alternative to suture for repair of central tears. Thirteen-millimeter arrows may be effective for central and peripheral tears. Ten-millimeter arrows should not be used.
Subject(s)
Absorbable Implants , Menisci, Tibial/surgery , Analysis of Variance , Animals , Biomechanical Phenomena , Cattle , Chi-Square Distribution , Equipment Failure Analysis , In Vitro Techniques , Stress, Mechanical , Suture TechniquesABSTRACT
BACKGROUND: Surgical treatment of ankle fractures in patients with diabetes mellitus is associated with a high complication rate. Diabetic patients with peripheral neuropathy are a particularly difficult group to treat because of their inability to sense deep infection, repeat trauma, and wound complications. The purpose of this study was to evaluate a protocol that included transarticular fixation and prolonged, protected weightbearing in the treatment of unstable ankle fractures in diabetic patients with peripheral neuropathy and loss of protective sensibility. METHODS: The authors retrospectively reviewed the records of 15 patients with diabetes mellitus, unstable ankle fractures (AO classification 44B), and loss of protective sensibility confirmed via testing with a 5.07 Semmes-Weinstein monofilament. Retrograde transcalcaneal-talar-tibial fixation using large Steinmann pins or screws in conjunction with standard techniques of open reduction and internal fixation was used. The postoperative treatment protocol included: 1) short leg, total contact casting and nonweightbearing status for 12 weeks; 2) removal of the intramedullary implants between 12 and 16 weeks; 3) application of a walker boot or short leg cast with partial weightbearing for an additional 12 weeks; and 4) transition to a custom-molded ankle-foot orthosis (AFO) or custom total-contact inserts in appropriate diabetic footwear. RESULTS: The major complication rate for all fractures was 25% (4/16) and for closed fractures was 23% (3/13). These are lower than previously reported rates between 30% (3/10) and 43% (9/21) for diabetic patients with and without neuropathy. The amputation rate for all fractures was 13% (2/16) and for closed fractures alone was 8% (1/13). These are similar to previously reported rates of 10% (2/10) to 20% (2/21). There were no deaths or Charcot malunions in this series. The combination of transarticular fixation and prolonged, protected weightbearing provided 13 of 15 patients with a stable ankle for weightbearing. CONCLUSION: Although these fractures remain a treatment challenge, this study presents a successful, multidisciplinary protocol for treatment of unstable ankle fractures in the most challenging group of diabetic patients - those with loss of protective sensibility.
