Daniel Dornacher1, Angela Trubrich2, Joachim Guelke3, Heiko Reichel2, Thomas Kappe2. 1. Department of Orthopedics, University of Ulm, Oberer Eselsberg 45, 89081, Ulm, Germany. daniel.dornacher@uni-ulm.de. 2. Department of Orthopedics, University of Ulm, Oberer Eselsberg 45, 89081, Ulm, Germany. 3. Department of Traumatology, Hand and Reconstructive Surgery, University of Ulm, Albert-Einstein-Allee 23, 89081, Ulm, Germany.
Abstract
PURPOSE: Regarding TT-TG in knee realignment surgery, two aspects have to be considered: first, there might be flaws in using absolute values for TT-TG, ignoring the knee size of the individual. Second, in high-grade trochlear dysplasia with a dome-shaped trochlea, measurement of TT-TG has proven to lack precision and reliability. The purpose of this examination was to establish a knee rotation angle, independent of the size of the individual knee and unaffected by a dysplastic trochlea. METHODS: A total of 114 consecutive MRI scans of knee joints were analysed by two observers, retrospectively. Of these, 59 were obtained from patients with trochlear dysplasia, and another 55 were obtained from patients presenting with a different pathology of the knee joint. Trochlear dysplasia was classified into low grade and high grade. TT-TG was measured according to the method described by Schoettle et al. In addition, a modified knee rotation angle was assessed. Interobserver reliability of the knee rotation angle and its correlation with TT-TG was calculated. RESULTS: The knee rotation angle showed good correlation with TT-TG in the readings of observer 1 and observer 2. Interobserver correlation of the parameter showed excellent values for the scans with normal trochlea, low-grade and high-grade trochlear dysplasia, respectively. All calculations were statistically significant (p < 0.05). CONCLUSION: The knee rotation angle might meet the requirements for precise diagnostics in knee realignment surgery. Unlike TT-TG, this parameter seems not to be affected by a dysplastic trochlea. In addition, the dimensionless parameter is independent of the knee size of the individual. LEVEL OF EVIDENCE: II.
PURPOSE: Regarding TT-TG in knee realignment surgery, two aspects have to be considered: first, there might be flaws in using absolute values for TT-TG, ignoring the knee size of the individual. Second, in high-grade trochlear dysplasia with a dome-shaped trochlea, measurement of TT-TG has proven to lack precision and reliability. The purpose of this examination was to establish a knee rotation angle, independent of the size of the individual knee and unaffected by a dysplastic trochlea. METHODS: A total of 114 consecutive MRI scans of knee joints were analysed by two observers, retrospectively. Of these, 59 were obtained from patients with trochlear dysplasia, and another 55 were obtained from patients presenting with a different pathology of the knee joint. Trochlear dysplasia was classified into low grade and high grade. TT-TG was measured according to the method described by Schoettle et al. In addition, a modified knee rotation angle was assessed. Interobserver reliability of the knee rotation angle and its correlation with TT-TG was calculated. RESULTS: The knee rotation angle showed good correlation with TT-TG in the readings of observer 1 and observer 2. Interobserver correlation of the parameter showed excellent values for the scans with normal trochlea, low-grade and high-grade trochlear dysplasia, respectively. All calculations were statistically significant (p < 0.05). CONCLUSION: The knee rotation angle might meet the requirements for precise diagnostics in knee realignment surgery. Unlike TT-TG, this parameter seems not to be affected by a dysplastic trochlea. In addition, the dimensionless parameter is independent of the knee size of the individual. LEVEL OF EVIDENCE: II.
Authors: Philip B Schoettle; Marco Zanetti; Burkart Seifert; Christian W A Pfirrmann; Sandro F Fucentese; Jose Romero Journal: Knee Date: 2005-07-14 Impact factor: 2.199
Authors: Gerd Diederichs; Torsten Köhlitz; Evgenios Kornaropoulos; Markus O Heller; Bernd Vollnberg; Sven Scheffler Journal: Am J Sports Med Date: 2012-11-07 Impact factor: 6.202