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Management of humeral and glenoid bone loss--associated with glenohumeral instability
DiPaola, Matthew J; Jazrawi, Laith M; Rokito, Andrew S; Kwon, Young W; Patel, Lava; Pahk, Brian; Zuckerman, Joseph D
Anterior glenohumeral instability complicated by bone loss is a challenging problem and, when severe, may require surgical treatment with bone grafting. We review our institution's experience with humeral head and glenoid bone grafting for large Hill-Sachs lesions and glenoid defects. MATERIALS AND METHODS: Patients who underwent intra-articular bone reconstruction for Hill-Sachs and large glenoid defects for anterior instability at our institution during 2002-2008 were retrospectively reviewed. Those who had undergone concomitant humeral head replacement were excluded. Six patients were identified as having undergone allograft or autograft iliac crest bone graft reconstruction of the glenoid, with four available for full follow-up (average 39 months; range, 7 to 63). Five patients were identified as having undergone humeral head allograft reconstruction and four were available for full follow-up (average 28 months; range, 11 to 40). The remaining three patients were available for telephone follow-up. American Shoulder and Elbow Society (ASES) and University of California, Los Angles (UCLA) scores were recorded and radiographs obtained. RESULTS: Average postoperative ASES and UCLA scores for glenoid bone graft patients were 91 and 33, respectively. Average postoperative ASES and UCLA scores for humeral bone graft patients were 85.3 and 28.4, respectively. Glenoid bone graft shoulders, when compared to the opposite normal side, lost an average of 3 degrees of forward flexion, 10 degrees of external rotation, and two levels of internal rotation. Humeral head bone-grafted shoulders, lost an average of 23 degrees of forward flexion, 8 degrees of external rotation, and two levels of internal rotation. No episodes of recurrent subluxation or dislocations were reported. Radiographs showed no evidence of graft resorption or hardware prominence. CONCLUSIONS: Bone grafting procedures around the shoulder for the treatment of instability provided relief from recurrent instability and good functional results
PMID: 21162700
ISSN: 1936-9727
CID: 133848
Analysis of reverse total shoulder joint forces and glenoid fixation
Kwon, Young W; Forman, Rachel E; Walker, Peter S; Zuckerman, Joseph D
Reverse total shoulder arthroplasty (rTSA) implants are intended to restore stability and function to shoulders with rotator cuff deficiency. The implant consists of a glenosphere projecting from a glenoid baseplate and articulating in a socket at the proximal end of a humeral component. Despite the demonstrated clinical efficacy, little information is available regarding the joint forces about this construct and the stability of the glenoid component against these forces. Our hypotheses were that the joint forces about the rTSA were comparable to that about a normal shoulder joint, and that the micromotion between the baseplate and the scapula against these loads would be sufficiently low to induce bone ingrowth. To investigate this, a custom testing rig was constructed to simulate active shoulder elevation in fresh-frozen shoulder specimens. The forces about the rTSA were calculated and found to include compressive and shear forces up to 0.7 and 0.4 BW, respectively. In contrast to a normal shoulder, where the joint forces peak at 90 degrees of abduction, forces about the rTSA were highest at about 60 degrees of abduction. These forces were then applied in cyclic loading conditions to the glenoid baseplate, and the micromotion of the implant relative to the bone was measured in the four quadrants of the component. For two different rTSA designs (DePuy Delta III(R) and Encore RSP(R)) and in the entire range of the fixation testing, the cyclical micromotions were always less than 62 microm. Thus, under loading conditions similar to physiological shoulder elevation, micromotion of the glenoid component was sufficiently low and within previously published limits to induce bone ingrowth
PMID: 21162705
ISSN: 1936-9727
CID: 117344
A novel method to determine suture anchor loading after rotator cuff repair--a study of two double-row techniques
Khoury, Lisa D; Kwon, Young W; Kummer, Frederick J
BACKGROUND: The addition of a lateral suture anchor fixation row to rotator cuff repairs has been shown to improve initial cuff reattachment strength and footprint area. This study evaluated the mechanical function of this lateral row by measuring suture tensions at the individual anchor sites. MATERIALS AND METHODS: Eight cadaveric shoulders underwent simulated rotator cuff repairs, using either double row or suture-bridge repair techniques. Suture tensions at each anchor were measured for several static, simulated shoulder positions relevant to postoperative patient management by specially designed instrumented anchors. RESULTS: Significantly greater suture tensions were measured at the medial anchor sites than at the lateral sites for the double-row (p < 0.001), as well as the suture-bridge constructs (p < 0.016). In the double-row technique, the lateral row sustained 21% (range, 6 to 31) of the total anchor load; whereas, in the suture-bridge technique, the lateral row sustained 33% (range, 8 to 42). Shoulder abduction from 45 degrees to 60 degrees had little effect on anchor tensions; 20 degrees internal and external rotation significantly (p = 0.032) increased loads on the anterior and posterior anchors. CONCLUSIONS: Forces are transmitted through the entire body of the tendon at its humeral fixation, loading the lateral anchors, as well as the medial row, for the two fixation techniques studied. These findings explain the higher laboratory-obtained fixation strengths of double-row techniques. The magnitude and distribution of anchor suture tensions could have important implications for postoperative positioning and activity
PMID: 20345359
ISSN: 1936-9727
CID: 120731
Snapping scapula syndrome
Lazar, Meredith A; Kwon, Young W; Rokito, Andrew S
Snapping scapula syndrome arises from either a soft-tissue or a skeletal anomaly within the scapulothoracic space that creates a cracking sound during scapulothoracic motion that patients associate with pain. Nonoperative measures consisting of supervised physical therapy, anti-inflammatory medications, and therapeutic injections are the mainstay of treatment. Open, arthroscopic, and combined operative approaches have been described for the treatment of refractory cases, with good overall outcomes in many relatively small case series. However, the optimal operative approach has yet to be determined
PMID: 19724005
ISSN: 1535-1386
CID: 101965
Management of massive and irreparable rotator cuff tears
Neri, Brian R; Chan, Keith W; Kwon, Young W
Massive rotator cuff tears pose a distinct clinical challenge for the orthopaedist. In this review, we will discuss the classification, diagnosis, and evaluation of massive rotator cuff tears before discussing various treatment options for this problem. Nonoperative treatment has had inconsistent results and proven unsuccessful for chronic symptoms while operative treatment including debridement and partial and complete repairs have had varying degrees of success. For rotator cuff tears that are deemed irreparable, treatment options are limited. The use of tendon transfers in younger patients to reconstruct rotator cuff function and restore shoulder kinematics can be useful in salvaging this difficult problem.
PMID: 19487132
ISSN: 1058-2746
CID: 566882
Open reduction and internal fixation of capitellar fractures with headless screws. Surgical technique
Ruchelsman, David E; Tejwani, Nirmal C; Kwon, Young W; Egol, Kenneth A
BACKGROUND: The outcome of operatively treated capitellar fractures has not been reported frequently. The purpose of the present study was to evaluate the clinical, radiographic, and functional outcomes following open reduction and internal fixation of capitellar fractures that were treated with a uniform surgical approach in order to further define the impact on the outcome of fracture type and concomitant lateral column osseous and/or ligamentous injuries. METHODS: A retrospective evaluation of the upper extremity database at our institution identified sixteen skeletally mature patients (mean age, 40 +/- 17 years) with a closed capitellar fracture. In all cases, an extensile lateral exposure and articular fixation with buried cannulated variable-pitch headless compression screws was performed at a mean of ten days after the injury. Clinical, radiographic, and elbow-specific outcomes, including the Mayo Elbow Performance Index, were evaluated at a mean of 27 +/- 19 months postoperatively. RESULTS: Six Type-I, two Type-III, and eight Type-IV fractures were identified with use of the Bryan and Morrey classification system. Four of five ipsilateral radial head fractures occurred in association with a Type-IV fracture. The lateral collateral ligament was intact in fifteen of the sixteen elbows. Metaphyseal comminution was observed in association with five fractures (including four Type-IV fractures and one Type-III fracture). Supplemental mini-fragment screws were used for four of eight Type-IV fractures and one of two Type-III fractures. All fractures healed, and no elbow had instability or weakness. Overall, the mean ulnohumeral motion was 123 degrees (range, 70 degrees to 150 degrees ). Fourteen of the sixteen patients achieved a functional arc of elbow motion, and all patients had full forearm rotation. The mean Mayo Elbow Performance Index score was 92 +/- 10 points, with nine excellent results, six good results, and one fair result. Patients with a Type-IV fracture had a greater magnitude of flexion contracture (p = 0.04), reduced terminal flexion (p = 0.02), and a reduced net ulnohumeral arc (p = 0.01). An ipsilateral radial head fracture did not appear to affect ulnohumeral motion or the functional outcome. CONCLUSIONS: Despite the presence of greater flexion contractures at the time of follow-up in elbows with Type-IV fractures or fractures with an ipsilateral radial head fracture, good to excellent outcomes with functional ulnohumeral motion can be achieved following internal fixation of these complex fractures. Type-IV injuries may be more common than previously thought; such fractures often are associated with metaphyseal comminution or a radial head fracture and may require supplemental fixation
PMID: 19255199
ISSN: 1535-1386
CID: 93739
Atraumatic osteonecrosis of the humeral head
Gruson, Konrad I; Kwon, Young W
While much literature has focused on the management of osteonecrosis of the femoral head, far less information is available regarding the treatment and outcomes of this disease in the proximal humerus. To a great extent, management of humeral head osteonecrosis has been inferred from studies involving the femoral head. The etiologies for this disease can be categorized most usefully as traumatic versus atraumatic. Regardless of the underlying etiology, the common pathway involves disruption of the arterial inflow or the venous outflow of the bone, with resultant osseous cell death. The general treatment strategies for humeral head osteonecrosis include nonoperative modalities for symptomatic early disease, with surgical intervention reserved for more advanced disease or those with recalcitrant pain
PMID: 19302052
ISSN: 1936-9719
CID: 99280
Tendon transfers for irreparable rotator cuff tears
Neri, Brian R; Chan, Keith W; Kwon, Young W
PMID: 19302053
ISSN: 1936-9719
CID: 99281
Proximal biceps tendon--a biomechanical analysis of the stability at the bicipital groove
Kwon, Young W; Hurd, Jason; Yeager, Keith; Ishak, Charbel; Walker, Peter S; Khan, Sami; Bosco, Joseph A 3rd; Jazrawi, Laith M
The subscapularis tendon, coracohumeral ligament, and transverse humeral ligament are all believed to contribute to biceps tendon stability within the bicipital groove. In order to examine the relative contribution of these soft tissue structures to proximal biceps tendon stability, 11 fresh frozen cadaveric shoulder specimens were prepared and mounted onto a custom jig. A three-dimensional digitizer was utilized to record biceps tendon excursion in various shoulder positions. In sequential order, these structures were then sectioned, and biceps tendon excursion was again recorded. We found that sectioning of the subscapularis tendon significantly increased biceps tendon excursion, compared to intact specimens (8.1 +/- 4.1 mm vs. 4.3 +/- 3.6 mm; p < 0.006). In contrast, isolated sectioning of the transverse humeral ligament or the coracohumeral ligament did not significantly increase biceps excursion (5.4 +/- 2.5 mm, p = 0.26; 5.6 +/- 1.3 mm, p = 0.24). When two structures were sectioned, significant excursion in the biceps tendon only occurred in specimens where the subscapularis tendon was one of the sectioned structures. The preliminary data suggest that, of the three tested soft tissue structures, the subscapularis tendon is the most important stabilizer of the proximal biceps and that clinically significant lesions of the proximal biceps tendon may be associated with a defect in the subscapularis tendon
PMID: 20001935
ISSN: 1936-9727
CID: 105972
Complications of Arthroscopic Shoulder Surgery: Miscellaneous Shoulder Conditions
Chapter by: Golant, Alexander; Kwon, Young W.
in: Complications In Knee And Soulder Surgery by Meislin, RJ; Halbrecht, J [Eds]
pp. 265-272
ISBN: 978-1-84882-202-3
CID: 5297932