肘部产生的肌肉微撕裂伤可能是导致出现外侧和内上髁炎症状的病理过程。[3]Milz S, Tischer T, Buettner A, et al. Molecular composition and pathology of entheses on the medial and lateral epicondyles of the humerus: a structural basis for epicondylitis. Ann Rheum Dis. 2004;63:1015-1021.http://ard.bmj.com/content/63/9/1015.longhttp://www.ncbi.nlm.nih.gov/pubmed/15308511?tool=bestpractice.com在外上髁炎中,病损常发于桡侧腕短伸肌起源处,但是也可能源于指总伸肌或桡侧腕长伸肌腱。[4]Jobe FW, Ciccotti MG. Lateral and medial epicondylitis of the elbow. J Am Acad Orthop Surg. 1994;2:1-8.http://www.ncbi.nlm.nih.gov/pubmed/10708988?tool=bestpractice.com[5]Bunata RE, Brown DS, Capelo R. Anatomic factors related to the cause of tennis elbow. J Bone Joint Surg Am. 2007;89:1955-1963.http://www.ncbi.nlm.nih.gov/pubmed/17768192?tool=bestpractice.com
[Figure caption and citation for the preceding image starts]: 同一患者接受冠状位 MRI 和轴位 MRI,显示桡侧腕短伸肌的信号高由加利福尼亚州圣地亚哥海军医学中心的 Daniel J. Solomon 提供;经许可后使用 [Citation ends].在内上髁炎中,病损可能发于旋前圆肌、桡侧腕屈肌、掌长肌、指浅屈肌和尺侧腕屈肌。[6]Rosenberg N, Soudry M, Stahl S. Comparison of two methods for the evaluation of treatment in medial epicondylitis: pain estimation vs grip strength measurements. Arch Orthop Trauma Surg. 2004;124:363-365.http://www.ncbi.nlm.nih.gov/pubmed/15108009?tool=bestpractice.com[7]Descatha A, Leclerc A, Chastang JF, et al; The Study Group on Repetitive Work. Medial epicondylitis in occupational settings: prevalence, incidence and associated risk factors. J Occup Environ Med. 2003;45:993-1001.http://www.ncbi.nlm.nih.gov/pubmed/14506342?tool=bestpractice.com
[Figure caption and citation for the preceding image starts]: 难治性内上髁炎手术:在实施椭圆形切口后,提起退行性肌腱的剥离部位以切除该部位由加利福尼亚州圣地亚哥海军医学中心的 Brian Fitzgerald 医生提供;经许可后使用 [Citation ends].一般认为,肌肉微断裂是肘部所受反复外翻力所致,导致在源发部位受到应力和肌肉损伤。[16]Ciccotti MC, Schwartz MA, Ciccotti MG. Diagnosis and treatment of medial epicondylitis of the elbow. Clin Sports Med. 2004;23:693-705.http://www.ncbi.nlm.nih.gov/pubmed/15474230?tool=bestpractice.com[19]Bauer JA, Murray RD. Electromyographic patterns of individuals suffering from lateral tennis elbow. J Electromyogr Kinesiol. 1999;9:245-252.http://www.ncbi.nlm.nih.gov/pubmed/10437977?tool=bestpractice.com
还有人提出桡肱关节中突出的滑膜皱襞可能起到机械刺激物的作用,从而引发外上髁炎。[20]Tsuji H, Wada T, Oda T, et al. Arthroscopic, macroscopic, and microscopic anatomy of the synovial fold of the elbow joint in correlation with the common extensor origin. Arthroscopy. 2008;24:34-38.http://www.ncbi.nlm.nih.gov/pubmed/18182199?tool=bestpractice.com[21]Ruch DS, Papadonikolakis A, Campolattaro RM. The posterolateral plica: a cause of refractory lateral elbow pain. J Shoulder Elbow Surg. 2006;15:367-370.http://www.ncbi.nlm.nih.gov/pubmed/16679240?tool=bestpractice.com
组织学研究和能量多普勒超声最近已确认外上髁近端和远端血供较少的部位。[22]Bales CP, Placzek JD, Malone KJ, et al. Microvascular supply of the lateral epicondyle and common extensor origin. J Shoulder Elbow Surg. 2007;16:497-501.http://www.ncbi.nlm.nih.gov/pubmed/17254813?tool=bestpractice.com[23]du Toit C, Stieler M, Saunders R, et al. Diagnostic accuracy of Power-Doppler ultrasound in patients with chronic tennis elbow. Br J Sports Med. 2008;42:572-576.http://www.ncbi.nlm.nih.gov/pubmed/18308874?tool=bestpractice.com 这些血供过少的部位与前臂伸肌总腱中具有高风险微撕裂的区域紧密相关,有可能使该组织更易受损。
损伤后,受损肌腱的特征为水肿,伴有正常平行走向的胶原纤维的撕裂。[12]Tuite MJ, Kijowski R. Sports-related injuries of the elbow: an approach to MRI interpretation. Clin Sports Med. 2006;25:387-408.http://www.ncbi.nlm.nih.gov/pubmed/16798134?tool=bestpractice.com
[Figure caption and citation for the preceding image starts]: 难治性内上髁炎手术:退行性肌腱部位上放置的探头显示肌腱正常外观丧失由加利福尼亚州圣地亚哥海军医学中心的 Brian Fitzgerald 医生提供;经许可后使用 [Citation ends].也有报道称,在上髁炎组织中会发生纤维母细胞和血管肉芽(称作血管纤维母细胞增生)侵袭。[24]Nirschl RP, Pettrone FA. Tennis elbow. The surgical treatment of lateral epicondylitis. J Bone Joint Surg Am. 1979;61:832-839.http://www.ncbi.nlm.nih.gov/pubmed/479229?tool=bestpractice.com[25]Kraushaar BS, Nirschl RP. Tendinosis of the elbow (tennis elbow): clinical features and findings of histological, immunohistochemical, and electron microscopy studies. J Bone Joint Surg Am. 1999;81:259-278.http://www.ncbi.nlm.nih.gov/pubmed/10073590?tool=bestpractice.com 在进一步的组织学评估中,外上髁炎患者的伸肌总腱的肌腱存在钙化替代造成肌腱细胞丧失的情况,表明在损伤后发生了组织重构。[26]Chard MD, Cawston TE, Riley GP, et al. Rotator cuff degeneration and lateral epicondylitis: a comparative histological study. Ann Rheum Dis. 1994;53:30-34.http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1005239/pdf/annrheumd00489-0037.pdfhttp://www.ncbi.nlm.nih.gov/pubmed/8311552?tool=bestpractice.com