Abstract
The majority of studies reporting sensitivity and specificity data for imaging modalities and physical examination tests for long head of biceps (LHB) tendon pathology use arthroscopy as the gold standard. However, there is little published data to validate this as an appropriate benchmark. The aim of this study was to determine the maximum length of the LHB tendon that can be seen at glenohumeral arthroscopy and whether it allows adequate visualisation of common sites of pathology.
Seven female cadaveric specimens were studied. Mean age was 74 years (range 44–96 years). Each specimen underwent arthroscopy in lateral decubitus (LD) and beach chair (BC) positions. The LBH-tendon was tagged with a suture placed with a spinal needle marking the intra-articular length and the maximum excursions achieved using a hook and a grasper in both LD and BC positions. T-tests were used to compare data.
The mean intra-articular and extra-articular lengths of the tendon were 23.9 mm and 82.3 mm respectively. The mean length of tendon that could be visualised by pulling it into the joint with a hook was significantly less than with a grasper (LD: hook 29.9 mm, grasper 33.9 mm, mean difference 4 mm, p=0.0032. BC: hook 32.7 mm, grasper 37.6 mm, mean difference 4.9 mm, p=0.0001). Using the BC position allowed visualisation of a significantly greater length than the LD position when using either a hook (mean difference 2.86 mm, p=0.0327) or a grasper (mean difference 3.7 mm, p=0.0077). The mean length of the extra-articular part of the tendon visualised using a hook was 6 mm in LD and 8.9 mm in BC. The maximum length of the extra-articular portion visualised using this technique was 14 mm (17%).
Pulling the tendon into the joint with a hook does not allow adequate visualisation of common distal sites of pathology in either LD or BC. Although the BC position allows a significantly greater proportion of the tendon to be visualised this represents a numerically small value and is not likely to be clinically significant. The use of a grasper also allowed greater excursion but results in iatrogenic tendon injury which precludes its use. The reported incidence of pathology in Denard zone C (distal to subscapularis) is 80% and in our study it was not possible to evaluate this zone even by using a grasper or maximum manual force to increase excursion. This is consistent with the extremely high rate of missed diagnoses reported in the literature. Surgeons should be aware that the technique of pulling the LHB-tendon into the joint is inadequate for visualising distal pathology and results in a high rate of missed diagnoses. Furthermore, efforts to achieve greater excursion by “optimum” limb positioning intra-operatively do not confer an important clinical advantage and are probably unnecessary.
