ObjectiveTo introduce and analyze the role of tibial tubercle internal rotation to treat recurrent patellar dislocation associated with trochlear dysplasia. MethodsBetween February 2007 and April 2011, 28 patients with recurrent patellar dislocation underwent tibial tubercle translocation through medial transfer, rotation and elevation of the tibial tuberosity and the medial patellofemoral ligament (MPFL) reconstruction. There were 4 males and 24 females with an average age of 21.8 years (range, 17-28 years). The disease duration ranged from 6 months to 8 years (mean, 4 years). The patients suffered from 3-10 times patellar dislocation. The result of apprehension test was positive; Lysholm score was (51.64±3.79); Kujala score was (56.89±3.79). According to Dejour classification, 11 cases were rated as type B, 14 cases as type C, and 3 cases as type D; the tibial tuberosity-trocholear distance (TT-TG) was (20.53±2.58) mm; and the patellar tilt angle (PTA) was (29.34±2.54)°. ResultsPrimary healing of incision was obtained in the others except 1 case of mild infection. Twenty-seven patients were followed up 41.8 months on average (range, 27-74 months). No recurrent dislocation was found, and the result of apprehension test was negative. The knee range of motion restored to normal totally. The postoperative Kujala score and Lysholm score were significantly improved to 88.97±3.06 and 88.95±2.98 (t=-42.005, P=0.000; t=-43.122, P=0.000) respectively. TT-TG and PTA restored to normal[(11.77±2.24) mm and (7.99±2.57)°], showing significant differences when compared with preoperative ones(t=13.032, P=0.000; t=29.533, P=0.000). ConclusionThe technique of tibial tubercle translocation and MPFL reconstruction is an effective surgical procedure for the treatment of recurrent patellar dislocation associated with trochlear dysplasia. Especially, tibial tubercle internal rotation can improve the patella stability and knee function.
ObjectiveTo investigate the effect of medial 1/3 anatomical orientation of the tibial tubercle on the rotational alignment of Gemini MK-Ⅱ tibial components in total knee arthroplasty (TKA). MethodsBetween March 2011 and December 2012, 61 cases (67 knees) of varus knee osteoarthritis underwent Gemini MK-Ⅱ knee arthroplasty, and the clinical data were retrospectively analyzed. There were 12 males and 49 females, with an average age of 67.6 years (range, 50-82 years). The body mass index ranged from 20.9 to 33.7 kg/m2 (mean, 28.2 kg/m2). Unilateral TKA was performed in 55 cases and bilateral TKA in 6 cases. The duration of knee osteoarthritis ranged from 2 to 30 years (mean, 12.1 years). According to radiographic changes, 56 knees were rated as Kellgren-Lawrence grade Ⅲ and 11 knees as grade IV. During TKA, the tibial rotational alignment was determined by medial 1/3 anatomical orientation of the tibial tubercle. The anteroposterior and lateral X-ray films and CT scan were taken to measure the tibial rotational angle (TRA) at pre-and post-operation and to analyze the relative factors for TRA by Pearson correlation analysis. ResultsAll the patients were followed up 18-41 months (mean, 20.5 months). The range of motion (ROM) significantly increased from (98.806±16.969)° preoperatively to (116.806±11.458)° at last follow-up (t=-11.760, P=0.000). The knee society score (KSS) significantly increased from 111.239±20.344 to 160.522±17.872 at last follow-up (t=-27.271, P=0.000). The anatomical tibiofemoral angle (ATFA), posterior condylar angle (PCA), and TRA were all improved after TKA, showing significant differences when compared with preoperative ones (P<0.05). Rotational malalignment was observed in 11 knees (16.42%) before TKA, and in 14 knees (20.90%) at 1 week after TKA, showing no significant difference (χ2=0.443, P=0.506). There were 8 knees (11.94%) of internal rotation (>8°) and 6 knees (8.96%) of external rotation (>8°). The postoperative tibial prosthesis TRA had no correlation with the preoperative ATFA and tibial plateau TRA, the postoperative PCA and ATFA (r=-0.174, P=0.159; r=0.220, P=0.074; r=0.237, P=0.053; r=-0.095, P=0.442). ConclusionIn patients with varus knee osteoarthritis, medial 1/3 anatomical orientation of the tibial tubercle will contribute to the development of tibial rotational malalignment when TKA is performed by using Gemini MK-Ⅱ tibial components.