The circumferential graft technique for treatment of multidirectional elbow instability: a comparative biomechanical evaluation.
BACKGROUND
Ligament reconstruction with a circumferential graft represents an innovative technique for treatment of multidirectional elbow instability. This biomechanical study compared the stability of the intact elbow joint with the circumferential graft technique and the conventional technique.


METHODS
Seven fresh frozen cadaveric elbows were evaluated for stability against valgus and varus/posterolateral rotatory forces (3 Nm) over the full range of motion. Primary stability was determined for intact specimens, after sectioning of the collateral ligaments, after applying the circumferential graft technique (box-loop), and after conventional collateral ligament reconstruction. Cyclic loading (1000 cycles) was performed to assess joint stability and stiffness of the native ligaments and the tendon grafts.


RESULTS
Primary stability of both reconstruction techniques was equal to the native specimens (P = .17-.91). Sectioning of the collateral ligaments significantly increased joint instability (P < .001). The reconstruction techniques provided equal stability after 1000 cycles (P = .78). Both were inferior to the intact specimens (P = .02). Cyclic loading caused a significantly lower increase in stiffness of the native ligaments compared with the tendon grafts of either reconstruction technique (P = .001-.008). Significantly better graft stiffness was retained with the circumferential graft technique compared with conventional reconstruction (P = .04).


CONCLUSIONS
Neither reconstruction technique fully reproduces the biomechanical profile of the native collateral ligaments. The circumferential graft technique seems to resist cyclic loading slightly better than the conventional reconstruction technique, yet both reconstruction techniques provide comparable stability.
Institute of Anatomy I, University of Cologne, Cologne, Germany; Center for Orthopedic and Trauma Surgery, University Medical Center, Cologne, Germany; Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany. Electronic address: michael.hackl@uk-koeln.de.
Michael
M
Hackl
Institute for Medical Engineering, University of Magdeburg, Magdeburg, Germany.
Nicolai
N
Heinze
Center for Orthopedic and Trauma Surgery, University Medical Center, Cologne, Germany; Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany.
Kilian
K
Wegmann
Center for Orthopedic and Trauma Surgery, University Medical Center, Cologne, Germany; Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany.
Sebastian
S
Lappen
Center for Orthopedic and Trauma Surgery, University Medical Center, Cologne, Germany; Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany.
Tim
T
Leschinger
Clinic for Shoulder Surgery, Bad Neustadt a.d.Saale, Germany.
Klaus Josef
KJ
Burkhart
Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany; Institute of Anatomy II, University of Cologne, Cologne, Germany.
Martin
M
Scaal
Center for Orthopedic and Trauma Surgery, University Medical Center, Cologne, Germany; Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany.
Lars Peter
LP
Müller
D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D017885:Collateral Ligaments / Q000601:surgery*; D004551:Elbow Joint / Q000601:surgery*; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000601:surgery*; D008297:Male; D019637:Orthopedic Procedures / Q000379:methods*; D013710:Tendons / Q000637:transplantation*
Box-loop ligament reconstruction; Circumferential graft technique; LUCL; UCL; biomechanical analysis; elbow instability; lateral collateral ligament; ulnar collateral ligament