2wu.qxd 2/10/04 11:19 AM Page 199 FEATURE ARTICLE The Influence of Iliotibial Tract on Patellar Tracking Chi-Chuan Wu, MD* Chun-Hsiung Shih, MD† Abstract Thirty patients with 49 snapping hips and patellar Significant improvements in the congruence angle and malalignment underwent surgical release of the iliotibial lateral patellofemoral angle were noted on Merchant tract contracture over the trochanteric area. Minimal fol- radiograph for all knees (PϽ.01). On CT, at 20° and 45° low-up was 2 years (average 4.6 years, range: 2-9 years). knee bending, all congruence, lateral patellofemoral, and Eight patients underwent computed tomography (CT) patellar tilt angles significantly improved postoperatively preoperatively and 1 month postoperatively to investigate in 8 knees (PϽ.01). Iliotibial tract affects patellar tracking the patellar location in the patellofemoral articulation with and dominates lateral patellar supporting structures. knee bending at 0°, 20°, 45°, 60°, and 90°. Anterior knee pain is common in orthope- patellar supporting structures have not yet examined regardless of the presence or dics and patellar malalignment is a com- been defined. absence of snapping hip.22,24,25 The clini- mon disorder that causes this pain.1-10 The Snapping hip, an uncommon disorder, cal features of patellofemoral pain syn- cause of patellar malalignment has been is caused by iliotibial tract contracture drome included aggravated anterior knee investigated and predisposing factors (external type).20-23 Snapping hip usually pain during stair climbing, knee soreness include an abnormal patellofemoral artic- is diagnosed because of discomfort or after prolonged sitting, and positive ulation, abnormal lower extremity align- snapping in the upper thigh. The senior grinding tenderness in the patellofemoral ment, and abnormal patellar supporting author (C.-C.W.) created a hypothesis that joint.7,19,26-28 When external snapping hip structures.11-13 Patellar tracking is most iliotibial tract contracture may cause was combined in the ipsilateral knee, commonly affected by abnormal patellar external snapping hip and patellar anteroposterior (AP) pelvic, AP and lat- supporting structures.11-13 malalignment. Therefore, treatment of eral knee, and Merchant tangential view Patellar malalignment usually occurs such a contracture could concomitantly radiographs were obtained.24 as lateral tilting or lateral patellar sublux- correct both disorders. If so, the impor- Patients who had both clinical disor- ation, which is due to weakened medial tance of the iliotibial tract related to patel- ders, malaligned patella on the Merchant soft tissues or tight lateral soft tissues lar tracking could be assessed. view, and normal patellofemoral articula- around the patella.7,14,15 Iliotibial tract also To test this hypothesis, a prospective tion and lower extremity alignment on affects patellar tracking.1,16-19 However, study was performed. A pilot clinical plain radiograph were candidates for sur- its role and importance regarding lateral study investigated the validity of the con- gical release of the iliotibial tract contrac- cept and computed tomography (CT) ture. Patients who had patellofemoral was supplemented to test the hypothesis. pain syndrome and snapping hip but no From the *Department of Orthopedics, Chang malaligned patellae on the Merchant Gung Memorial Hospital, Chang Gung Institute of Technology, Taoyuan; and the †Department of MATERIALS AND METHODS radiograph were excluded due to the Orthopedics, Kang Ning General Hospital, Pilot Study inability to objectively evaluate the Taipei, Taiwan. From February 1993 to July 2000, improvement quantitatively. This study was supported by the National all consecutive patients (aged Ͻ40 The 7-year pilot study included 37 Science Council (NSC 88-2314-B-182A-062), years) who presented to the senior patients and 60 hips. Average patient age Executive Yuan, China. Reprint requests: Chi-Chuan Wu, MD, Dept of author’s (C.-C.W.) orthopedic out- was 28 years (range: 21-35 years) with a Orthopedics, Chang Gung Memorial Hospital, 5 patient department due to patello- 1:2 male to female ratio. Twenty-three Fu-Hsin St, 333, Kweishan, Taoyuan, Taiwan. femoral pain syndrome were routinely patients had bilateral disorders and 14 www.orthobluejournal.com 199 2wu.qxd 2/10/04 11:19 AM Page 200 ORTHOPEDICS FEBRUARY 2004 VOL 27 NO 2 unilateral. Duration of anterior knee graphs were recorded. Quadriceps angle, and patellar tilt angle was evalu- pain was intermittent for several months strengthening and hamstring stretching ated using two-tailed paired Student’s t to several years. Conservative treatment exercises were encouraged. test. PϽ.05 was considered statistically did not improve pain. Trochanteric area Knee function was evaluated using significant. soreness was noted in 22 hips, with sev- Micheli’s grading and four grades were The correlation of lateral patello- eral months’ to several years’ intermit- divided. A satisfactory result included femoral angle and patellar tilt angle tent duration. an excellent or good outcome.18 Patellar was evaluated using Pearson correla- No abnormal patellofemoral articula- tracking was evaluated by congruence tion coefficient (r). tions or lower extremity malalignments angle and lateral patellofemoral angle. were noted in these patients. Twenty-six RESULTS knees had lateral patellar subluxation Computed Tomography Study Pilot Study and 34 knees had simple lateral patellar From August 1998 to July 2000, all Thirty patients with 49 knees under- tilting. In this study, patellar malalign- consecutive new patients were exam- went minimum 2-year follow-up (aver- ment was defined as lateral patellar sub- ined with CT (HiSpeed Advantage; GE age, 4.6 years; range: 2-9 years). Knee luxation with an abnormal congruence Medical Systems, Milwaukee, Wis) function improved in 41 knees (P=.001). angle (Ͼ0°)29,30 and lateral patellar tilt- over the upper, middle, and lower Seven patients could not be contacted. ing with a normal congruence angle but patella with knee bending at 0°, 20°, Congruence angle improved from abnormal lateral patellofemoral angle 45°, 60°, and 90°. 8°Ϯ9.6° to 1.6°Ϯ7.8° (P=.004). Lateral (Ͻ0°).18,31,32 Eight patients were included in this patellofemoral angle improved from study. Average patient age was 29 years Ϫ1.3°Ϯ5.8° to 7.5°Ϯ4.9° (PϽ.001) Operative Technique (range: 22-34 years) with a 1:2 male to (Figure 1). Under spinal anesthesia, patients female ratio. All patients had bilateral No wound infection or other compli- were placed in the supine position with disorders, and no abnormal patello- cations were noted. the affected hip elevated. With the hip in femoral articulation or lower extremity full flexion and adduction, a 2-cm skin malalignment was noted. Computed Tomography Study incision was made longitudinally along Computed tomography was obtained All 8 patients (16 knees) underwent the posterior border of the femur, just preoperatively and 1 month postopera- CT. Preoperatively, patellae were later- distal to the greater trochanter. The skin tively. Further CT could not be obtained ally subluxed (congruence angle Ͼ0°) was extracted and the underlying fascia due to monetary expense. Consequently, with 0°, 20°, or 45° knee bending (Table was exposed. The fascia was transverse- only a Merchant radiograph was regular- 1). However, because the femoral artic- ly dissected with a scalpel from the pos- ly taken at follow-up. Daily activity was ular surface was partly blurred, patellar terior toward the anterior aspect of the not restricted postoperatively. location could not be measured with 60° thigh. The hip was gradually extended, Patellar location in the patello- or 90° knee bending. allowing the contracted fascia to slide femoral articulation was investigated. One month postoperatively, patellar backward. Dissection continued until all The best (clearest) of three scans over subluxation was not significantly snapping resolved. different levels of the patella was cho- improved with 0° knee bending. With index finger palpation, only sen. In addition to the congruence and However, significant improvement was involved contracted soft tissues were lateral patellofemoral angles, patellar noted with 20° and 45° knee bending released. Contracted soft tissues that did tilt angle also was measured. Patellar (PϽ.01), and the laterally subluxed not contribute to the snapping hip were lateral subluxation was determined by patellae had been reduced to normal preserved without release. The hip was congruence angle and patellar lateral location (Figure 2). tested in adduction-flexion to adduc- tilting, lateral patellofemoral, or patel- With 0° knee bending, lateral patello- tion-extension and back and forth to lar tilt angles (Ͻ8°).30 femoral angle and patellar tilt angle was ensure complete release. After hemo- positive pre- and postoperatively. The stasis was achieved, the wound was Statistical Analysis improvement was not significantly sig- closed with absorbable sutures. A closed In the pilot study, knee function nificant. drain was inserted according to the improvement was evaluated using With 20° knee bending, lateral amount of bleeding.25 Fisher’s exact test and change of con- patellofemoral angle was negative pre- Postoperatively, patients were permit- gruence angle and lateral patello- operatively and improved postopera- ted to ambulate without aids as early as femoral angle was evaluated using two- tively (PϽ.01). Patellar tilt angle was possible. Daily activity was increased