Screws or Sutures? A Pediatric Cadaveric Study of Tibial Spine Fracture Repairs

Abstract

Background: Tibial spine fractures are common in the pediatric population because of the biomechanical properties of children’s subchondral epiphyseal bone. Most studies in porcine or adult human bone suggest that suture fixation performs better than screw fixation, but these tissues may be poor surrogates for pediatric bone. No previous study has evaluated fixation methods in human pediatric knees. Purpose: To quantify the biomechanical properties of 2-screw and 2-suture repair of tibial spine fracture in human pediatric knees. Study Design: Controlled laboratory study. Methods: Cadaveric specimens were randomly assigned to either 2-screw or 2-suture fixation. A standardized Meyers-Mckeever type 3 tibial spine fracture was induced. Screw-fixation fractures were reduced with two 4.0-mm cannulated screws and washers. Suture-fixation fractures were reduced by passing 2 No. 2 FiberWire sutures through the fracture fragment and the base of the anterior cruciate ligament. Sutures were secured through bony tunnels over a 1-cm tibial cortical bridge. Each specimen was mounted at 30° of flexion. A cyclic loading protocol was applied to each specimen, followed by a load-to-failure test. Outcome measures were ultimate failure load, stiffness, and fixation elongation. Results: Twelve matched pediatric cadaveric knees were tested. Repair groups had identical mean (8.3 years) and median (8.5 years) ages and an identical number of samples of each laterality. Ultimate failure load did not significantly differ between screw (mean ± SD, 143.52 ± 41.9 7 N) and suture (135.35 ± 47.94 N) fixations ( P = .760). Screws demonstrated increased stiffness and decreased elongation, although neither result was statistically significant at the .05 level (21.79 vs 13.83 N/mm and 5.02 vs 8.46 mm; P = .076 and P = .069, respectively). Conclusion: Screw fixation and suture fixation of tibial spine fractures in human pediatric tissue were biomechanically comparable. Clinical Relevance: Suture fixations are not biomechanically superior to screw fixations in pediatric bone. Pediatric bone fails at lower loads, and in different modes, compared with adult cadaveric bone and porcine bone. Further investigation into optimal repair is warranted, including techniques that may reduce suture pullout and “cheese-wiring” through softer pediatric bone. This study provides new biomechanical data regarding the properties of different fixation types in pediatric tibial spine fractures to inform clinical management of these injuries.

Clinical and Functional Outcomes of Suture Versus Headless Screw Fixation for Tibial Eminence Fractures in Children

“…In a biomechanical meta-analysis, no significant difference was found between suture and screw fixations in terms of stiffness and displacement after cyclic testing in adults. 33 In the only biomechanical study conducted for children, Johnstone et al 10 recently showed that suture and screw fixations of TEFs in pediatric human cadavers were biomechanically similar. Additionally, those authors found that pediatric bone fails at lower loads compared with adult cadaveric bone and porcine bone.…”

“…Additionally, those authors found that pediatric bone fails at lower loads compared with adult cadaveric bone and porcine bone. 10 Given the low ultimate failure loads observed for both suture and screw fixation methods in pediatric specimens, the postoperative rehabilitation program for children should differ from that in adults. In the present study, a full extension knee brace was used, with no knee movement allowed for 2 weeks postoperatively, and weightbearing was restricted until the end of the fourth postoperative week.…”

“…14,21,32 Senekovic and Balazic 22 found that SF was biomechanically more reliable than screw fixation, whereas Tsukada et al 29 showed that screw fixation was biomechanically superior to SF. However, Mahar et al 16 and Johnstone et al 10 found no significant biomechanical difference between suture and screw fixation in TEF treatment. Clinical studies comparing suture and screw fixation for TEF have consistently revealed no significant difference in clinical or radiographic outcomes.…”

Arthroscopic fixation techniques for tibial eminence fractures in pediatric patients: a review

“…However, the above study specimens were not representative of the characteristics of children's skeleton, Johnstone et al ( 38 ) matched the age and side of 12 knees from 6 children's cadavers, and divided them into a double screw group and the suture group, in which the double screw group was fixed with two 4 mm × 35 mm partially threaded cannulated screws, and the suture group was fixed with two No. 2 FiberWire sutures through the anterior 1/3 and posterior 1/3 of the cruciate ligament, and then pulled through the bone tunnels on the medial and lateral side of the fracture fragment to be knotted and fixed outside the joint.…”

The modified suture-bridge technique for treating avulsion fracture of minors tibial eminence of anterior cruciate ligament: a retrospective study

“…The arthroscopic reduction and internal fixation techniques can use a variety of fixation methods, such as metal screws [ 10 ], sutures [ 11 – 13 ], and suture anchors [ 14 ]. Of these methods, most biomechanical studies of porcine or human bone show that suture fixation is superior to screw fixation [ 15 ]. Although there are various biochemical comparative studies of arthroscopic tibial eminence fracture fixation methods, the best choice of technique remains controversial [ 16 – 19 ].…”