Introduction: There is controversy regarding the effectiveness of PRC for bone healing. A possible explanation is the different bone graft substitutes (BGSs) used with PRC. Here we investigated the effect of combining different BGSs with PRC on hBMSCs differentiation and growth factor release from the BGS/PRC composites.

Method: hBMSCs, DBM and allograft were prepared from femoral heads donated by patients undergoing total hip replacement. Growth factor release (TGF-â, VEGF, PDGF-AB, BMP-2) was measured by ELISA. The effect of PRC on hBMSC differentiation was determined by ALP activity and mineralisation. PRC was produced using the CAPTION device (S& N) from 10 healthy volunteers.

Results: Combining PRC with BGSs increased hBMSC proliferation (p< 0.05) and decreased ALP activity (p< 0.05) compared to DBM or â-TCP (GenOS, S& N) alone, but had no effect on allograft following 3 and 5 days treatment. After 21 days PRC enhanced mineralisation compared to all BGSs alone (16%–56%). Compared to PRC alone addition of DBM and allograft increased proliferation (p< 0.05), decreased ALP activity (p< 0.005) and decreased mineralisation (p< 0.005). TGF-â, VEGF and BMP-2 release from PRC was unaffected when combined with DBM but PDGF-AB release was reduced by 50%.

Conclusions: Combining PRC with the majority of BGSs enhanced cell proliferation and decreased osteoblastic differentiation at early time points but increased total mineralisation compared to the BGSs alone. However, compared to PRC alone combining DBM or allograft with PRC reduced mineralisation. One potential explanation for the effects of combining PRC with DBM is altered growth factor release profiles compared to the components alone.

We dissected 105 cadaveric shoulders to study the origin of the tendon of the long head of biceps, and examined histologically the interrelationship between the tendon, the supraglenoid tubercle and the superior labrum of the glenoid. In all specimens approximately 50% of the biceps tendon arose directly from the superior glenoid labrum with the remainder attached to the supraglenoid tubercle. The main labral origin was from the posterior labrum in more than half of the specimens, and in a quarter this was the only labral attachment. On the basis of the biceps attachment to the anterior or posterior labrum, we distinguished four types of origin. These normal anatomical variations are significant for arthroscopic diagnosis and may help to explain the various patterns of injury seen in partial or complete detachment of the tendon, the labrum or both.