RESUMEN
BACKGROUND: Extracortical single-button (SB) inlay repair is a commonly used distal biceps tendon technique. However, complications (eg, neurovascular injury) and nonanatomic repairs have led to the development of intracortical fixation techniques. PURPOSE: To compare the biomechanical stability of extracortical SB repair with an anatomic intracortical double-button (DB) repair technique. STUDY DESIGN: Controlled laboratory study. METHODS: The distal biceps tendon was transected in 18 cadaveric elbows from 9 donors. One elbow of each donor was randomly assigned to the extracortical SB or anatomic DB group. Both groups were cyclically loaded with 60 N over 1000 cycles between 90° of flexion and full extension. The elbow was then fixed in 90° of flexion and the repair construct loaded to failure. Gap formation and construct stiffness during cyclic loading and ultimate load to failure were analyzed. RESULTS: When compared with the extracortical SB technique after 1000 cycles, the anatomic DB technique showed significantly less gap formation (mean ± SD, 2.7 ± 0.8 vs 1.5 ± 0.9 mm; P = .017) and significantly more construct stiffness (87.4 ± 32.7 vs 119.9 ± 31.6 N/mm; P = .023). Ultimate load to failure was not significantly different between the groups (277 ± 93 vs 285 ± 135 N; P = .859). The failure mode in the anatomic DB group was significantly different from that of the extracortical SB technique (P = .002) and was due to fracture avulsion of the cortical button in 7 of 9 specimens (vs none in the SB group). CONCLUSION: Our study shows that the intracortical DB technique produces equivalent or superior biomechanical performance to that of the SB technique. The DB technique may offer a clinically viable alternative to the SB repair technique. CLINICAL RELEVANCE: This study suggests, at worst, an equivalent and, at best, a superior biomechanical performance of intracortical anatomic DB footprint repair at the time of surgery. However, the mode of failure suggests that this technique should not be used in patients with poor bone quality.
Asunto(s)
Articulación del Codo , Traumatismos de los Tendones , Humanos , Codo/cirugía , Traumatismos de los Tendones/cirugía , Tendones/cirugía , Articulación del Codo/cirugía , Técnicas de Sutura , Fenómenos Biomecánicos , CadáverRESUMEN
BACKGROUND: Neer type IIB lateral clavicle fractures are inherently unstable fractures with associated disruption of the coracoclavicular (CC) ligaments. Because of the high rate of nonunion and malunion, surgical fixation is recommended; however, no consensus has been reached regarding the optimal fixation method. A new plating technique using a superior lateral locking plate with anteroposterior (AP) locking screws, resulting in orthogonal fixation in the lateral fragment, has been designed to enhance stability and reduce implant failure. The purpose of this study was to biomechanically compare 3 different clavicle plating constructs within a fresh frozen human cadaveric shoulder model. METHODS: Twenty-four fresh frozen cadaveric shoulders were randomized into 3 groups (n = 8 specimens): group 1, lateral locking plate only (Medartis Aptus Superior Lateral Plate); group 2, lateral locking plate with CC stabilization (No. 2 FiberWire); and group 3, lateral locking plate with 2 AP locking screws stabilizing the lateral fragment. All specimens were subject to cyclic loading of 70 N for 500 cycles. Data were analyzed for gap formation after cyclic loading, construct stiffness, and ultimate load to failure, defined by a marked decrease in the load displacement curve. RESULTS: After 500 cycles, there was no statistically significant difference between the 3 groups in gap formation (P = .179). No specimen (0/24) failed during cyclic loading. Ultimate load to failure was significantly higher in group 3 compared to group 1 (286 N vs. 167 N; P = .022), but not to group 2 (286 N vs. 246 N; P = .604). There were no statistically significant differences in stiffness (group 1: 504 N/mm; group 2: 564 N/mm; group 3: 512 N/mm; P = .712). Peri-implant fracture was the primary mode of failure for all 3 groups, with group 3 demonstrating the lowest rate of peri-implant fractures (group 1: 6/8; group 2: 7/8; group 3: 4/8; P = .243). CONCLUSION: Biomechanical evaluation of the clavicle plating techniques showed effective fixation across all specimens at 500 cycles. The lateral locking plate with orthogonal AP locking screw fixation in the lateral fragment demonstrated the greatest ultimate failure load, followed by the lateral locking plate with CC stabilization. This new plating technique showed compatible stiffness and gap formation when compared to conventional lateral locking plates as well as plates with CC fixation. The use of orthogonal screw fixation in the distal fragment may negate against the need for CC stabilization in these types of fractures, thus minimizing surgical dissection around the coracoid and potential complications.
Asunto(s)
Clavícula , Fracturas Óseas , Humanos , Fenómenos Biomecánicos , Placas Óseas , Cadáver , Clavícula/cirugía , Fijación Interna de Fracturas/métodos , Fracturas Óseas/cirugía , Ligamentos ArticularesRESUMEN
HYPOTHESIS: Simple transverse or short oblique olecranon fractures without articular comminution are classified as Mayo type IIA fractures and are typically treated with a tension band wire construct. Because of the high reoperation rates, frequently because of prominent hardware, all-suture tension band constructs have been introduced. It was the purpose to compare the biomechanical performance of conventional tension band wire fixation with a new all-suture tension band tape fixation for simple olecranon fractures. METHODS: Mayo type IIA olecranon fractures were created in 20 cadaveric elbows from 10 donors. One elbow of each donor was randomly assigned to the tension band wire technique (group TBW) or tension band tape (Arthrex, 1.3-mm SutureTape) technique (group TBT). Both groups were cyclically loaded with 500 N over 500 cycles, after which a uniaxial displacement was performed to evaluate load to failure. Data were analyzed for gap formation after cyclic loading, construct stiffness, and ultimate load to failure, where failure was defined as fracture gap formation greater than 4.0 mm. RESULTS: There was no significant difference in gap formation after 500 cycles between the TBW (1.8 mm ± 1.3 mm) and the TBT (1.9 mm ± 1.1 mm) groups (P = .854). The TBT showed a tendency toward greater construct stiffness compared with the TBW construct (mean difference: 142 N/mm; P = .053). Ultimate load to failure was not significantly different comparing both groups (TBW: 1138 N ± 286 N vs. TBT: 1126 N ± 272 N; P = .928). In both groups, all repairs failed because of >4.0-mm gap formation at the fracture site and none because of tension band construct breakage. CONCLUSIONS: Our study shows that the TBT technique produces equivalent or superior biomechanical performance to the TBW for simple olecranon fractures. The TBT approach reduces the risk of hardware prominence and as a result mitigates against the need for hardware removal. The TBT technique offers a clinically viable alternative to TBW.