Introduction Cruciate ligament ruptures and shoulder dislocations are often caused by trauma, but predisposing intrinsic factors might also influence the risk. Collagen type V is widely distributed in tissues and helps regulate the diameters of fibrils of the abundant collagen type I. Mutations in its genes have been identified which can result in connective tissue fragility, particularly in skin and joints.

The aim of this study was to localise collagen V in skin, hamstring tendons and shoulder capsules of patients following sports injuries.

Patients and methods Localisation of collagen V was studied by immunohistochemical staining of paraffin embedded sections of skin, tendons and capsules of patients attending for shoulder stabilisation for recurrent instability or primary anterior cruciate ligament (ACL) reconstruction between November 2008 and July 2009.

Results 40 patients were studied, 25 undergoing primary ACL reconstruction and 15 undergoing shoulder stabilisation. The mean age of patients was 26 years. 34 patients (85%) were male and 6 female (15%). Most common sport played was football in 13 patients (32%) followed by rugby in 10 (25%) and skiing in 5 (12%).

Skin epidermis stained negative but dermal papilla, papillary and reticular dermis, blood vessels, sweat glands, sebaceous glands and arrector pilli stained positive to varying degrees for collagen V. Synovial surface of the capsule, blood vessels and extracellular matrix stained positive to varying degrees. Tendon sheath, collagen fibres, blood vessels and interfascicular connective tissue stained positive to varying degrees, but skeletal muscle was negative for collagen V.

Discussion We looked at the expression and distribution of collagen V in skin, tendons and capsules of patients undergoing shoulder stabilisation or ACL reconstruction following sports injuries. There may be a link in the distribution of collagen V and strength of tissues, which can predispose individuals to injuries while playing sports and can also affect healing process. Further studies are needed to study this link.