1887

The shoulder

image of The shoulder
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Abstract

This chapter discusses a range of congenital/developmental and acquired causes of shoulder lameness. Includes . : Craniomedial approach to the shoulder; Craniolateral approach to the shoulder; Caudolateral approach to the shoulder; Caudolateral arthrotomy for osteochondritis dissecans of the humeral head; Arthroscopy of the shoulder joint; Lateral shoulder stabilization; Medial shoulder stabilization – imbrication of the subscapularis muscle; Medial shoulder stabilization – placement of a medial collateral prosthesis; Tenotomy or tenodesis of the biceps brachii tendon of origin.

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Figures

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18.1 Surgical anatomy of the shoulder. (a) Osseous structures in the dog, lateral aspect. (b) Osseous structures in the cat, lateral aspect. (c) Ligaments and nerves of the shoulder joint, lateral aspect in the dog. (d) Ligaments of the shoulder joint, medial aspect in the dog. (e) Superficial muscles over the lateral aspect of the shoulder in the dog. (f) Deep muscles over the lateral aspect of the shoulder in the dog. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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18.2 Congenital shoulder luxation. Mediolateral radiograph of the shoulder of a 3-month-old Jack Russell Terrier with medial luxation. There is deformity of the articular surfaces, making the joint inherently unstable. Orthogonal views are advised but the direction of luxation – medial or lateral – is usually evident on examination.
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18.3 Shoulder dysplasia. Mediolateral radiograph of the left shoulder of a 3-year-old Bassett Hound that showed intermittent lameness associated with shoulder pain. The glenoid appears shallow and the humeral head flattened.
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18.4 Radiographic appearance of shoulder osteochondritis dissecans (OCD). (a) Mediolateral radiograph of the shoulder of a 5-month-old Bernese Mountain Dog. A subchondral defect is clearly present in the caudal humeral head, with a sclerotic margin. (b) Mediolateral radiograph of the shoulder of an 11-month-old Border Collie. The caudal humeral head appears flattened and a mineralized flap is evident in the caudal joint space. (c) Multiplanar CT reconstructions of an 11-month-old crossbreed dog with shoulder OCD. A large subchondral defect (thick arrows) in the humeral head and mineralized intra-articular detached flap fragments (thin arrows) are visible. (Courtesy of Gordon Brown)
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18.5 (a) Mediolateral arthrogram of a Great Dane with shoulder osteochondritis dissecans (OCD). A low dose of contrast medium is required, otherwise the articular surface of interest becomes obliterated; with such a low dose the tendon sheath of the biceps brachii is often poorly filled. (b) A low-dose normal arthrogram for comparison. Note the intact cartilage line over the humeral head.
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18.6 Arthroscopic view of an osteochondritis dissecans (OCD) lesion of the humeral head. (Arrows indicate the OCD cleavage site.)
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18.7 Arthroscopic view of a mildly displaced incomplete ossification of the caudal glenoid (arrowed).
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18.8 Acquired shoulder luxation. (ai) Mediolateral and (aii) craniocaudal radiographs of the shoulder of a 2-year-old Yorkshire Terrier with lateral luxation as a result of being attacked by another dog. Note the apparently normal appearance of the joint in the mediolateral view. (bi) Mediolateral and (bii) craniocaudal radiographs of the shoulder of a 12-year-old Shetland Sheepdog, showing medial luxation resulting from the dog being ‘extracted’ from under an armchair. (a, Courtesy of ARS Barr)
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18.9 Application of a Velpeau sling for the treatment of medial shoulder luxation. (a) The bandage is used to hold the distal humerus adducted against the chest wall. (b) Cotton wool is placed around the antebrachium for padding. (c) The entire limb is enclosed in the bandage, including the cranial aspect, so that the dog does not step out of the sling. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission. (Redrawn after the )
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18.10 Application of a non-weight-bearing sling for the treatment of lateral shoulder luxation. (a–b) The distal limb is flexed and the antebrachium bandaged to the body. (c) The entire limb is enclosed in the bandage, including the cranial aspect, so that the dog does not step out of the sling. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission. (Redrawn after the )
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18.11 Mediolateral postoperative radiograph of a 9-year-old Toy Poodle following placement of a transarticular pin to stabilize a medial subluxation after revision surgery to replace a collateral prosthesis. The first prosthesis had failed after 2 weeks. The pin was left for 4 weeks and the shoulder remained stable.
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18.12 Patients with contracture of the infraspinatus muscle may adopt this typical posture when sitting. The elbow is held adducted with the distal limb externally rotated. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission. (Redrawn after the )
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18.13 (a) Sagittal plane PD-weighted and (b) T2*GRE MR images and (c) caudocranial radiograph of a 4-year-old Labrador Retriever with lameness due to infraspinatus tendonopathy. There is dystrophic mineralization present within the tendon (arrowed). Identifying small areas of soft tissue mineralization may be difficult on MRI and it is easier to identify on the radiograph. (Courtesy of Torrington Orthopaedics)
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18.14 Bicipital tenosynovitis. (a) Mediolateral radiograph of a 12-year-old Border Collie with thoracic limb lameness associated with pain on shoulder extension or direct pressure applied over the biceps tendon. There is new bone deposition superimposed on the greater tubercle. (b) A tangential view shows osteophytes medial to the greater tubercle. (c) Mediolateral arthrogram (post injection of 6 ml of contrast medium) of a shoulder of a 7-year-old Airedale that was showing similar signs to the dog in (a). There is poor filling of the bicipital tendon sheath. (d) A normal arthrogram for comparison. (e) Ultrasound image showing a thickened biceps tendon of mixed heterogenous echogenicity (black arrow) surrounded by increased fluid (the black surrounding ring). The white arrow indicates the cranial aspect of the greater tubercle. (e, Courtesy of Gareth Arthurs and Marie-Aude Genain)
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18.15 Arthroscopic view of the biceps tendon (black arrow) showing severe synovial hyperaemia at the proximal end of the tendon and of the craniomedial joint capsule (white arrows).
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18.16 Avulsion of the biceps brachii tendon. (a) Mediolateral radiograph of the shoulder of a 4-year-old Irish Setter that developed acute onset thoracic limb lameness. The biceps brachii tendon had avulsed from the scapular tuberosity, from which a small fragment of bone has also been avulsed. (b) Arthroscopic view of an avulsed biceps tendon. (c) Arthroscopic view of a partial biceps tendon avulsion in a 7-year-old Bernese Mountain Dog. (c, Courtesy of Simon Gilbert)
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18.17 Mediolateral arthrogram of a 4-year-old Border Collie, showing leakage of contrast agent from the distal margin of the biceps tendon sheath, possibly indicating rupture.
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18.18 Medial displacement of the biceps brachii tendon of origin. (a) Intraoperative image after medial placement of two stabilizing screws. The biceps tendon is indicated by the arrow and is positioned lateral to the screws. (b) Postoperative radiograph following relocation of the tendon in the intertubercular groove and stabilization with two 4.0 mm partially threaded cancellous screws. (Courtesy of Malcolm McKee)
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18.19 (a) Mediolateral radiograph of a 9-year-old German Shepherd Dog showing mineralization over the cranial aspect of the greater tubercle in the vicinity of the supraspinatus tendon of insertion. There is also mineralization further caudally, which could involve the intertubercular groove. (b) Transverse CT image at the level of the greater tubercle showing mineralization craniomedial to the greater tubercle, consistent with supraspinatus tendon mineralization. (c) Fat-saturated three-dimensional fast spoiled gradient-echo sequence (3D-WATSC) MR image of supraspinatus mineralization (arrowed) in a dog. (di–ii) PD-weighted fat-saturated MR images of non-mineralized supraspinatus tendinopathy showing increased signal in the supraspinatus muscle tendon on the medial aspect of the greater tubercle insertion and slight medial displacement of the biceps tendon with some flattening. (Courtesy of Gordon Brown)
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18.20 (a) Mediolateral and (b) craniocaudal radiographs, showing mineralization within the infraspinatus bursa. (Courtesy of WM McKee)
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18.21 Medial shoulder instability: arthroscopic views. (a) Normal medial glenohumeral ligament (arrowed). (b) Normal medial glenohumeral ligament (arrowed) and subscapularis tendon with partial tearing (arrowhead).
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18.22 Lateral shoulder instability: arthroscopic views. (a) Normal lateral glenohumeral ligament. (b) Ruptured lateral glenohumeral ligament (arrowed).
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18.23 (a) Mediolateral postoperative radiograph of a 6-year-old Dobermann treated for chronic recurrent septic arthritis of the glenohumeral joint by arthrodesis. (b–c) Following arthrodesis, mobility through the omothoracic junction allows a good range of motion through the distal limb to compensate for loss of movement in the scapulohumeral joint. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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18.24 Patient positioning for a mediolateral view of the shoulder. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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18.25 (a) Mediolateral and (b) mediolateral slightly pronated views of the shoulder. The flattening and adjacent fine mineralized flap on the caudal aspect of the humeral head are not apparent on the original image, but mild pronation skylines the lesion more effectively.
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18.26 Patient positioning for a caudocranial view of the shoulder. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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18.27 Patient positioning for a cranioproximal–craniodistal view of the shoulder.
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18.28 Patient positioning for CT examination of the shoulder.
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18.29 CT arthrograms of the shoulder of a dog. The biceps tendon (BT) can be seen within the tendon sheath, as well as the medial glenohumeral (MGH) and lateral glenohumeral (LGH) ligaments.
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18.30 Ultrasound image of the shoulder of a dog showing the linear fibres of the biceps tendon (BT) originating from the supraglenoid tubercle (SGT) and passing over the proximal humerus (H).
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18.31 Transverse T1-weighted MR image (postarthrogram) of the shoulder of a dog, showing the biceps tendon (BT), infraspinatus tendon (IST) and supraspinatus tendon (SST).
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18.32 Craniomedial approach to the shoulder. (a) With the dog in dorsal recumbency, the limb is drawn caudally and the incision made over the craniomedial aspect of the joint. (b) The fascia is incised to allow retraction of the brachiocephalicus muscle. (c) The superficial and deep pectoral muscles are released from their insertion on the humerus. (d) Retraction of the pectoral muscles exposes the biceps brachii tendon of origin. (e) Exposure of the more proximal part of the tendon can be improved by osteotomy of the greater tubercle. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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18.33 Craniolateral approach to the shoulder. (a) With the dog in lateral recumbency a skin incision is made from about a third to halfway up the scapular spine to the distal limit of the deltoid tuberosity, passing cranial to the acromion process. (b) An incision is made in the deep brachial fascia. The length of the incision is dictated by which structures are required to be exposed. Craniolateral approach to the shoulder. (c) Retraction of the acromial head of the deltoid muscle caudally exposes the insertions of the supraspinatus, infraspinatus and teres minor muscles, which can be incised and reflected to expose the lateral glenohumeral ligament and capsule. (d) Tenotomy of the acromial head of the deltoid muscle or osteotomy of the acromion process allows reflection of the deltoid muscle for improved exposure of the lateral aspect of the joint. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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18.34 If an acromion osteotomy has been performed, closure will include reattachment of the process with (a) wire sutures or (b) a pin and tension-band technique. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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18.35 Caudolateral approach to the shoulder. (a) With the dog in lateral recumbency a skin incision is made from midway down the scapular spine to the distal limit of the deltoid tuberosity, passing caudal to the acromion process. (b) The fascia overlying the deltoid muscle is incised over the division between the scapular and acromial heads of the muscle, which can be seen or palpated; the omobrachial vein normally forms the distal limit of this incision, and where the division meets the scapular spine forms the proximal limit. (c) Using blunt dissection the two heads of the deltoid muscle are then separated to the same limits as in (b). Caudolateral approach to the shoulder. (d) Cranial retraction of the acromial head and caudal retraction of the scapular head of the deltoid muscle exposes the teres minor muscle and the neurovascular bundle over the caudal joint capsule. (e) Undermining the neurovascular bundle with blunt dissection will allow it to move caudally, providing ready access to the caudal joint capsule, which is then incised to expose the caudal humeral head. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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18.36 Caudolateral approach to the shoulder achieved by separating between the scapular head of the deltoid muscle and lateral head of the triceps muscle. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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18.37 Surgical treatment of osteochondritis dissecans (OCD). (a) Landmarks for the incision. The circle marks the acromion and the dotted line the incision, which starts about halfway down the scapular spine and ends towards the distal extremity of the deltoid tuberosity. (b) Subcutaneous tissue is dissected and retracted to expose the fascia over the deltoid muscle. (c) An incision is made through the fascia over the division between the acromial and scapular heads of the deltoid muscle, which are then separated and retracted to expose the teres minor muscle and the neurovascular complex over the caudal joint capsule (compare with Figure 18.35d ). (d) The muscular branch of the axillary nerve and the caudal circumflex humeral vessels are then dissected from the joint capsule and are carefully retracted (if they do not ‘fall away’ on their own) while the teres minor muscle is retracted cranially. (e) The capsule is incised to expose the humeral head (compare with Figure 18.35e ). (f) Inward rotation of the shoulder is usually required to bring an OCD lesion into view; a Hohmann retractor (blunt) has been placed here for clarity but if such an instrument is used to explore the lesion, care should be taken to try to remove the cartilage flap first, otherwise the retractor may push it off into the medial joint space from where retrieval can prove difficult. (g) A probe is used to elevate the cartilage flap and prise it away from its medial attachments, preferably while the lateral edge is held firmly with forceps. (h) The cartilage flap is removed, preferably in one piece. (i) The defect on the humeral head is then examined to ensure that all the margins are clear of detached cartilage; any granulation tissue or fibrocartilage is left on the floor of the defect but any eburnated subchondral bone may be foraged in an attempt to improve vascularization and encourage the formation of fibrocartilage.
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18.38 Arthroscopy of the shoulder joint. (a) Skeleton model demonstrating the portals for a lateral shoulder arthroscopy. (b) Cadaver with lateral shoulder arthroscopy portals marked. (c) Arthroscope . A = arthroscope/camera portal; E = egress portal; I = instrument portal. (a, Reproduced from the )
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18.39 Lateral stabilization of the shoulder joint. (a) The caudal aspect of the scapular spine can be accessed by osteotomy of the acromion process, but separation of the two heads of the deltoid muscle will usually suffice; osteotomy is shown here for clarity. Lateral stabilization of the shoulder joint. (b) A lateral prosthesis of braided polyester or monofilament leader line is passed through a tunnel created in the distal scapular spine and a second tunnel drilled in the greater tubercle or (c) is anchored around or through an implant (bone screw with spiked washer, suture screw, tissue anchor) placed in the greater tubercle close to the insertion of the teres minor muscle. (d) Postoperative mediolateral radiograph of the shoulder of 3-year-old Border Collie treated for lateral luxation. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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18.40 Lateral shoulder stabilization including modification to combine lateral and medial stabilization. (a) The scapular neck and proximal humerus are exposed as shown in Figure 18.33 . (b) Transverse tunnels are created in the scapular neck and humerus close to the insertion of the teres minor muscle. A prosthesis of braided nylon or leader line is passed through these tunnels. (c) After repair of any available joint capsule, the prosthesis is tightened so the joint is stable but not restricted in range of motion, and tied (or crimped). (d) Position of the prosthesis. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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18.41 (a) Identification of the subscapularis muscle tendon of insertion (arrowed), supraspinatus muscle (white asterisk) and greater tubercle (black asterisk). (b) Placement of the horizontal mattress suture through the tendon of the subscapularis muscle.
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18.42 Medial stabilization of the shoulder joint. (a) Retraction of the pectoral muscle exposes the biceps brachii tendon of origin. (Note this is an extension of the technique shown in Figure 18.32d .) (b) Incisions are made in the coracobrachialis (*) and subscapularis (+) tendons to expose the joint capsule and glenohumeral ligament. Exposure can be helped by placement of Gelpi retractors or using a small Hohmann retractor caudal to the scapula and a second one under the supraspinatus muscle, passing cranial to the scapula. (c) Suture screws or tissue anchors are then introduced at the points of origin and insertion of the medial glenohumeral ligament, and two separate sutures of braided polyester or monofilament leader line are used to replace both the cranial and caudal components of the ligament. (Note that these are simplified drawings showing schematic examples of the surgical procedure. Certain anatomical features have been omitted for clarity.) Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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18.43 The biceps brachii tendon of origin is exposed by way of a craniomedial approach. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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18.44 Methods of achieving biceps tenodesis. (a) A ligament staple is used to secure the tendon to the proximal humerus; the tendon is then incised from the scapular tuberosity, folded over the staple and sutured to itself. (b) A bone screw and spiked washer are used to secure the tendon to the proximal humerus before or after it is incised from the scapular tuberosity. Drawn by S.J. Elmhurst BA Hons (www.livingart.org.uk) and reproduced with her permission.
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