Arthroscopic Knot Removal for Failed Superior Labrum Anterior-Posterior Repair Secondary to Knot-Induced Pain

Background: Studies on failed superior labrum anterior-posterior (SLAP) repair are increasing. However, the number of reports on treatment options for failed SLAP repair remains quite low, and the clinical results vary between different study groups. Purpose: To describe the clinical presentation of failed SLAP repair due to knot-induced pain and evaluate the efficacy of arthroscopic knot removal. Study Design: Case series; Level of evidence, 4. Methods: The authors retrospectively reviewed records of 11 patients (mean age, 24.6 ± 8.6 years; range, 17-43 years) with stable, healed SLAP lesions with knot-induced pain after arthroscopic fixation of unstable type II SLAP lesions. All patients demonstrated a positive compression-rotation test before knot removal. The mean follow-up duration after knot removal was 48.0 ± 37.4 months (range, 24-156 months). The mean duration between primary fixation and knot removal was 21.2 ± 14.7 months (range, 8-56 months). Results: Sharp pain (100%) and clicking (64%) were the most common symptoms. The knot was positioned on the glenoid side in 5 patients and the labral side in 6 patients. The knots on the glenoid side had associated humeral head cartilage damage. The mean University of California at Los Angeles score significantly improved from 15.2 points to 31.7 points after knot removal ( P = .003) Additionally, the mean Constant score greatly improved from a mean of 56.5 points to 89.8 points ( P = .003). At a mean of 3 weeks after surgery, we observed dramatic pain relief. Six weeks after surgery, the compression-rotation test was negative in all patients. Conclusion: The most common symptom of knot-induced pain after SLAP repair was persistent sharp pain followed by clicking. The knot appears to be a cause of pain in failed SLAP repairs, and arthroscopic knot removal can provide dramatic pain relief and significant improvement of clinical outcomes.

Smooth Surface Interpolation With Multiple Patches

This paper addresses the problem of interpolating point data with multiple patches. The specific issue addressed in this paper is the continuity between the patches used for interpolation. The procedure described in this paper maintains continuity by introducing an intermediate patch between the two patches used for interpolating the point data. This patch is formed by several Bezier patches that maintain continuity with the corresponding Bezier patches obtained by repeated knot insertion in the two interpolating patches. The blending Bezier patches are then converted to a blending B-spline patch by knot removal. It is shown that C1 continuity is obtained across the junction between each interpolating patch and the blending patch. The continuity, across each blending patch and the interpolation performance in the blending patch is also discussed. The paper presents results, of implementation on some typical surfaces.