Difference in knee rotation between total and unicompartmental knee arthroplasties during stair climbing.

PURPOSE: The purpose of this study was to compare knee kinematics during stair walking in patients with simultaneous total knee arthroplasty (TKA) and unicompartmental knee arthroplasties (UKA). It was hypothesized that UKA would reproduce more normalized knee kinematics than TKA during stair ascent and descent. METHODS: Six patients who received UKA in one knee and TKA in the other knee were included in the study. For this study, a four-step staircase was assembled with two force platforms being positioned at the centre of the second and third steps. Each patient was attached with 16 reflective markers at both lower extremities and was asked to perform five roundtrip trials of stair climbing. Kinematic parameters including stance duration, knee angle, vertical ground reaction force (GRF), joint reaction force, and moments were obtained and analysed using a10-camera motion system (VICON, Oxford, UK). Nonparametric Friedman test was used to compare the results between two arthroplasty methods and between stair ascent and descent. RESULTS: Compared to TKA, UKA knees exhibited significantly greater degree of rotation in transverse planes (5.0 degrees during ascent and 6.0 degrees during descent on average), but showed no difference in terms of the other parameters. When comparing the results during stair ascent with descent, overall greater knee angle, vertical GRF, joint reaction force, and moment were observed during stair descent. CONCLUSIONS: Both UKA and TKA knees have shown overall similar knee kinematics, though UKA knee may allow greater degree of rotation freedom, which resembles normal knee kinematics during stair walking.

Massive lumbar disc herniation with complete dural sac stenosis.

BACKGROUND: Large lumbar disc herniation (LDH) has been reported to have a greater tendency to resolve in clinical and pathomorphological evolutions. However, various definitions of large LDH have been used without validation, and the clinical symptoms of large LDH have not been fully elucidated. We conducted a retrospective analysis to determine the clinical characteristics and treatment outcome of massive LDH with complete dural sac stenosis. MATERIALS AND METHODS: We retrospectively reviewed 33 cases of LDH with complete dural sac stenosis on magnetic resonance imaging. Complete dural sac stenosis was defined as no recognizable rootlet and cerebrospinal fluid signal on T2-weighed axial MR images. The clinical outcome parameters included back pain, leg pain, Oswestry disability index (ODI), and neurological dysfunction. The paired t-test and Wilcoxon's signed rank test were used to compare serial changes in back pain, leg pain and neurological dysfunction. RESULTS: Mean duration of followup was 66 months (range 24 - 108 months). There were 24 male and 9 female. The mean age was 37 years (range 20 - 53 years). At presentation, mean visual analogue scales for back pain and leg pain were 75.3 ± 19.1 (range 12 - 100) and 80.2 ± 14.6 (range 0 -100), respectively. Mean ODI was 67.1 ± 18.8 (range 26 - 88). Neurological dysfunction was found in 9 patients (27.3%), and the bowel/bladder dysfunction was found in 2 patients (3.1%). Conservative treatment was performed in 21 patients (63.6%) with satisfactory results. Seven patients underwent decompressive surgery, and 5 underwent posterolateral fusion. CONCLUSIONS: A massive LDH with complete dural sac stenosis was found to be associated with severe back and leg pain at presentation, however surgical treatment can be deferred unless significant neurological symptoms occur.

Is the anterior tibial artery safe during ankle arthroscopy?: anatomic analysis of the anterior tibial artery at the ankle joint by magnetic resonance imaging.

BACKGROUND: Pseudoaneurysm of the anterior tibial artery (ATA) after ankle arthroscopy is an uncommon complication but can cause unexpected consequences. However, its contributing factor is not fully understood. HYPOTHESIS: Anatomic factors, such as ATA variations and the distance between the ATA and joint capsule, may contribute to the occurrence of pseudoaneurysm. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: The magnetic resonance images and medical records of 358 ankle cases were analyzed. According to locations of the ATA in relation to the peroneus tertius (PT) and the extensor digitorum longus (EDL) tendon on axial magnetic resonance imaging, patients were classified as type 1 (safe type), type 2 (increased risk type), or type 3 (high-risk type). In addition, distances between the anterior joint capsule and the ATA were measured to evaluate the thickness of the anterior fat pad, which contains the ATA and anterior compartment tendons. RESULTS: In 336 cases (93.8%), the ATA was located medial to the EDL (type 1, safe). In 7 cases (2.0%), the ATA was located lateral to the EDL and PT tendon (type 2, increased risk); and in 15 cases (4.2%), the branching artery was observed lateral to the EDL and PT tendon and the ATA was in the normal position (type 3, high risk). The mean distance between the anterior joint capsule and the ATA was 2.3 ± 1.1 mm. CONCLUSION: In 22 (6.2%) of the 358 cases, the ATA and its branches were located near the anterolateral ankle portal, which introduces the risk of vascular damage during arthroscopic surgery. Furthermore, the mean distance between the ATA and the joint capsule was only 2.3 ± 1.1 mm, and thus the ATA is very close to the anterior working space of the ankle joint. Careful preoperative evaluation and an intra-articular procedure may reduce the risk of vascular complications attributable to ankle arthroscopy.

Evaluation of transtibial double-bundle posterior cruciate ligament reconstruction using a single-sling method with a tibialis anterior allograft.

BACKGROUND: The authors devised a double-bundle posterior cruciate ligament reconstruction technique in combination with a single-sling method. However, the double-bundle technique needs more simplicity and a decreased possibility of failure. HYPOTHESIS: A novel surgical technique of transtibial double-bundle posterior cruciate ligament reconstruction using a single-sling method with a tibialis anterior allograft, previously introduced, produces satisfactory results. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Twenty-one patients who underwent double-bundle transtibial isolated posterior cruciate ligament reconstruction using a single-sling method between July 2003 and September 2007 were enrolled in this study. The exclusion criteria applied were (1) a multiligamentous injury, (2) posterior cruciate ligament reconstruction previously performed using another technique, and (3) the presence of any additional injury capable of affecting knee stability. The Lysholm and International Knee Documentation Committee (IKDC) knee scales were used for the clinical outcome evaluation. Stability was evaluated using a KT-2000 arthrometer. The evaluation was performed by comparing preoperative and last follow-up results. RESULTS: Nineteen men and 2 women were enrolled, with a mean follow-up of 49.2 months (range, 25-73 months). The mean Lysholm score was 53 ± 5.3 (range, 34-68) preoperatively and improved to 83.5 ± 13 (range, 61-97) at the last follow-up after surgery (P < .001). The IKDC score also improved from preoperative (0 A, 0 B, 7 C, 14 D) to final follow-up (8 A, 9 B, 3 C, 1 D; P < .001). Mean side-to-side difference in posterior translation, measured using the KT-2000 arthrometer, was 13.5 ± 1.2 mm preoperatively and 3.4 ± 0.8 mm at last follow-up evaluations (mean 51.7 months postoperatively). CONCLUSION: After follow-up for longer than 24 months, the transtibial double-bundle posterior cruciate ligament reconstruction with a single sling was found to produce satisfactory clinical and stability results, which indicates that the described technique should be viewed as a viable alternative.