Spencer and Kuhn compared three sternoclavicular joint reconstructions in cadavers: intramedullary ligament transfer, subclavius tendon reconstruction and a semitendinosus figure‑of‑eight graft.
Laboratory study of 36 fresh cadaveric specimens (donor mean age 74.9 years) at the University of Michigan.
Methods
Model
36 fresh cadaveric specimens
Mounted supine in a custom fixture on a materials testing machine
Constructs
Intramedullary ligament reconstruction
Subclavius tendon reconstruction
Semitendinosus figure‑of‑eight graft through clavicle and manubrium drill‑holes
6 specimens per technique in each direction
Loading
Intact joint: anterior and posterior subfailure translation after preloading
Reconstructed joint: anterior or posterior translation to failure
Outcome measures
Percent change in stiffness vs intact state
Peak load to failure
Key Findings
Posteriorly, the figure‑of‑eight graft lost only 3.8% of intact stiffness, vs 74.4% for the intramedullary and 82.3% for the subclavius reconstruction.
Anteriorly, the figure‑of‑eight lost 36.9% of stiffness vs 70.1% for the intramedullary technique (p = 0.004), but did not differ significantly from the subclavius technique's 56.9% (p = 0.078).
Subclavius reconstructions failed before reaching the target displacement in 4 of 6 specimens tested anteriorly and in all 6 tested posteriorly.
Most figure‑of‑eight constructs failed by fracture of the sternum or clavicle (8 specimens) rather than by tendon failure (4 specimens).
All three reconstructions were less stiff than the intact joint, both anteriorly (p = 0.013) and posteriorly (p = 0.003).
Board pearl
The figure‑of‑eight graft rebuilds both the anterior and posterior capsule because an earlier cadaver study had found the posterior capsule to be the main restraint to both anterior and posterior sternoclavicular translation.
Authors' conclusion
The figure-of-eight semitendinosus reconstruction for sternoclavicular joint instability has initial biomechanical properties that are superior to those of the intramedullary ligament reconstruction and subclavius tendon reconstruction techniques.
Spencer and Kuhn compared three sternoclavicular joint reconstructions in cadavers: intramedullary ligament transfer, subclavius tendon reconstruction and a semitendinosus figure‑of‑eight graft.
Laboratory study of 36 fresh cadaveric specimens (donor mean age 74.9 years) at the University of Michigan.
Methods
Model
36 fresh cadaveric specimens
Mounted supine in a custom fixture on a materials testing machine
Constructs
Intramedullary ligament reconstruction
Subclavius tendon reconstruction
Semitendinosus figure‑of‑eight graft through clavicle and manubrium drill‑holes
6 specimens per technique in each direction
Loading
Intact joint: anterior and posterior subfailure translation after preloading
Reconstructed joint: anterior or posterior translation to failure
Outcome measures
Percent change in stiffness vs intact state
Peak load to failure
Key Findings
Posteriorly, the figure‑of‑eight graft lost only 3.8% of intact stiffness, vs 74.4% for the intramedullary and 82.3% for the subclavius reconstruction.
Anteriorly, the figure‑of‑eight lost 36.9% of stiffness vs 70.1% for the intramedullary technique (p = 0.004), but did not differ significantly from the subclavius technique's 56.9% (p = 0.078).
Subclavius reconstructions failed before reaching the target displacement in 4 of 6 specimens tested anteriorly and in all 6 tested posteriorly.
Most figure‑of‑eight constructs failed by fracture of the sternum or clavicle (8 specimens) rather than by tendon failure (4 specimens).
All three reconstructions were less stiff than the intact joint, both anteriorly (p = 0.013) and posteriorly (p = 0.003).
Board pearl
The figure‑of‑eight graft rebuilds both the anterior and posterior capsule because an earlier cadaver study had found the posterior capsule to be the main restraint to both anterior and posterior sternoclavicular translation.
Authors' conclusion
The figure-of-eight semitendinosus reconstruction for sternoclavicular joint instability has initial biomechanical properties that are superior to those of the intramedullary ligament reconstruction and subclavius tendon reconstruction techniques.