The posterior ridge of the greater tuberosity of the humerus: a suitable landmark for the posterior approach to the shoulder joint?

BACKGROUND: The purpose of this study was to evaluate the posterior ridge of the greater tuberosity, a palpable prominence during surgery, as a landmark for the posterior approach to the glenohumeral joint. METHODS: Twenty-five human cadaveric shoulders were dissected. In 5 cases, a full-thickness rotator cuff tear was present. The posterior surgical anatomy was defined, and the distance from the ridge to the interval between the infraspinatus (IS) and teres minor (TM) muscle, the distance from the ridge to the inferior border of the glenoid (IBG), and the distance between the IS-TM interval and the IBG were determined. RESULTS: In all specimens, a prominent ridge on the posterior greater tuberosity lateral to the articular margin could be identified. The IS-TM interval was located, on average, 3 mm proximal to this ridge. The IS-TM interval corresponded to a point 5 mm proximal to the IBG. In all shoulders, the ridge was located, on average, 8 mm proximal to the IBG. The plane of the IS-TM interval showed a vertically oblique direction. CONCLUSION: The posterior ridge of the greater tuberosity is a suitable landmark to locate the internervous plane between the IS and TM and should not be crossed distally. Unlike other landmarks, the ridge moves with the humeral head, making it is less dependent on the patient's size, sex, and arm position and the quality of the rotator cuff. The ridge is always located proximal to the insertion of the TM and IBG.

Limitations of the Vastus Lateralis Muscle as a Substitute for Lost Abductor Muscle Function: An Anatomical Study.

Abductor insufficiency after hip arthroplasty resulting from an impaired gluteus medius and minimus remains an unsolved problem in orthopaedic surgery. The vastus lateralis (VL) was described as a functional substitute for abductor insufficiency in 2004. We carried out a macrodissection of twelve cadaveric hemipelvises to investigate the innervation of the VL and adjacent muscles to assess the extent the VL can be safely transferred. Results showed that direct muscle branches to proximal portions of the VL are too short to allow a significant shift; the shift may be as small as 13 mm. Nerves that supply the VL also extend to the vastus intermedius. This innervation pattern makes it impossible to shift the VL significantly without damaging branches to both.

Distal extension of the direct anterior approach to the hip poses risk to neurovascular structures: an anatomical study.

BACKGROUND: The anterior approach to the hip gained popularity for total hip arthroplasty in recent years. Distal extension of the anterior approach, sometimes needed intraoperatively, potentially endangers neurovascular structures to the quadriceps. The aim of this study was to determine the anatomical structures placed at risk by distal extension of the anterior approach to the hip. METHODS: Seventeen cadaveric hemipelves from twelve human specimens were dissected. The femoral nerve and its branches and the vessels arising from the lateral femoral circumflex artery were assessed in relation to the distal extension of the anterior approach. The damage caused by the introduction of a cerclage cable passer was also investigated. RESULTS: The area immediately distal to the intertrochanteric line is a common entry point for several nerve branches and is a useful distal landmark for surgeons to use to protect important neurovascular structures. The distal extension of the anterior approach compromises the nerve supply to the anterolateral portions of the quadriceps. Introduction of a cerclage cable passer through the anterior access also jeopardizes nerve branches to the vastus lateralis, lateral parts of the vastus intermedius, and branches of the lateral femoral circumflex artery. CONCLUSIONS: Distal extension of the direct anterior approach to the hip is challenging to accomplish without neurovascular injury to anterolateral parts of the quadriceps muscle group. In addition, important neurovascular structures are endangered with the introduction of a cable passer through the anterior approach. CLINICAL RELEVANCE: Distal extension of the direct anterior approach to the hip beyond the intertrochanteric line may compromise neurovascular structures supplying the quadriceps muscle.