Conscious neurosensory mapping of the internal structures of the human knee without intraarticular anesthesia.

The conscious neurosensory characteristics of the internal components of the human knee were documented by instrumented arthroscopic palpation without intraarticular anesthesia. With only local anesthesia injected at the portal sites, the first author (SFD) had both knees inspected arthroscopically. Subjectively, he graded the sensation from no sensation (0) to severe pain (4), with a modifier of either accurate spatial localization (A) or poor spatial localization (B). The nature of the intraarticular sensation was variable, ranging from 0 on the patellar articular cartilage to 4A on the anterior synovium, fat pad, and joint capsule. The sensation arising from the cruciate ligaments ranged from 1 to 2B in the midportion, and from 3 to 4B at the insertion sites. The sensation from the meniscal cartilages ranged from 1B on the inner rim to 3B near the capsular margin. Innervation of most intraarticular components of the knee is probably crucial for tissue homeostasis. Failure of current intraarticular soft tissue reconstructions of the knee may be due, in part, to the lack of neurosensory restoration. Research studies of the knee designed to delineate factors that restore neurosensory characteristics of the musculoskeletal system may lead to techniques that result in true restoration of joint homeostasis and function.