Localization of SP- and CGRP-immunopositive nerve fibers in the hip joint of patients with painful osteoarthritis and of patients with painless failed total hip arthroplasties.

Using immunohistochemical methods we determined the presence of SP- and CGRP-immunopositive nerve fibers in the hip joint of patients with femoral neck fracture (controls, group 1), painful osteoarthritis (group 2), and painless failed total hip arthroplasties (group 3). Immunoreactive nerve fibers were found in the soft tissue of the fossa acetabuli as well as in the subintimal part of the synovial layer in the hip joint capsule of groups 1 and 2. In the capsule of controls the innervation density had a median of 5.7fibers/cm(2) for CGRP-ir and 3.2fibers/cm(2) for SP-ir afferents. In the osteoarthritic group, the density significantly increased to a median of 15.6fibers/cm(2) for CGRP-ir and 8.2fibers/cm(2) for SP-ir neurons (p=0.05). Patients with failed hip arthroplasties completely lacked these neuropeptide containing afferents. Innervation density in the fossa acetabuli of osteoarthritc patients showed a median of 14.1fibers/cm(2) for CGRP-ir and 5.9fibers/cm(2) for SP-ir afferents. From these data we assume that the hip joint capsule and the soft tissue of the fossa acetabuli are important triggers of nociception. This is supported by the fact, that patients with loosened total hip arthroplasties, where we failed to detect SP- and CGRP-immunoreactive fibers, did not feel pain. The upregulation of SP- and CGRP-positive neurons in response to arthritic stages suggests a mechanism involving neuropeptides in the maintenance of a painful degenerative joint disease and in mediating noxious stimuli from the periphery. Furthermore, these findings help to explain clinical observations, such as effectiveness of local therapy to control hip pain with intraarticular injection, synovectomy and denervation procedures.

Misinterpretation of cup anteversion in total hip arthroplasty using planar radiography.

INTRODUCTION: Anteroposterior pelvic radiographs are routinely used to monitor cup orientation in total hip arthroplasty (THA). Analysis of planar radiographs leads to a certain degree of measurement error for the cup anteversion (AV). With the current study, we wanted to clarify whether planar radiography can be used for accurate evaluation of the THA position. MATERIALS AND METHODS: The postoperative orientation of pelvic implants in 42 patients was analyzed according to five documented mathematical algorithms using planar radiographs. Postoperative computed tomography (CT) pelvis scans were available for all patients. A CT-based navigation system was used to determine AV. RESULTS: The comparison showed that all five formulas presented substantial variations for the AV angle. Of these, Widmer's algorithm presented the smallest difference compared to the CT. Misinterpretation of postoperative planar radiographs is a common problem in THA. CONCLUSION: Planar radiographs are too imprecise for exact evaluation of the correct cup AV after THA. CT-based analysis may be necessary if exact values are required.

The long-term clinical sequelae of incidental durotomy in lumbar disc surgery.

STUDY DESIGN: A retrospective, long-term follow-up study. OBJECTIVES: To find out whether incidental durotomy in lumbar disc surgery is associated with long-term sequelae. SUMMARY OF BACKGROUND DATA: Incidental durotomy is a frequent complication during spinal surgery. Little is known about the clinical long-term outcome. METHODS: The study population comprised 1,280 patients who underwent standard discectomy of a lumbar disc herniation. A total of 41 patients with incidental durotomies (Group A) were compared with a control group (n = 41) (Group B) matched for age, sex, spinal level, and duration of follow-up. After a mean follow-up period of 10.2 years (Group A) or 10.3 years (Group B), the patients reported complaints, headache, and low back or leg pain. The patients' activity was assessed by means of a questionnaire concerning hindrance in daily activities, the Tegner score for general activities in daily life, and the Hannover Functional Ability Questionnaire for Measuring Back Pain-Related Functional Limitations (FFbH-R). The frequency of reoperation and the intake of analgesics were included. Furthermore, the patients' inability to work, change of profession, and retirement were registered. RESULTS: Patients with incidental durotomy had a poorer outcome after surgery. The Tegner score was significantly decreased for the group with dural tears. Furthermore, significant more patients with incidental durotomy complained about headaches after surgery. A strong tendency for worse outcome in Group A was shown in regard to reported complaints and daily activity. The patients with incidental durotomy had a tendency to more reoperations, a longer duration of inability to work, more back-pain, and functional limitations related to back-pain (FFbH-R). CONCLUSION: Our study revealed that incidental durotomy in lumbar disc surgery was associated with long-term clinical sequelae. We therefore conclude that dural tears bring about poor clinical outcome at the long-term follow-up.