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Background: The restoration of knee rotational stability after anatomic double-bundle anterior cruciate ligament (ACL) reconstruction has been demonstrated in the cadaveric model and with passive stress tests on humans but not yet with dynamic functional biomechanical tests performed by human participants. Purpose: To prospectively investigate the range of tibial rotation of ACL-deficient and ACL-reconstructed knees during a pivoting task. The authors hypothesized that there would be a significant increase in tibial internal rotation in the ACL-deficient knee compared with the contralateral knee and that the increased rotation would return to normal after anatomic double-bundle ACL reconstruction. Study Design: Case series; Level of evidence, 4. Methods: Ten men with unilateral ACL injury performed a high-demand jump-landing and pivoting task before and after ACL reconstruction with mean follow-up of 11 months. The range of tibial rotation of the injured, reconstructed, and intact knees during the pivoting movement was measured by an optical motion analysis system. Paired t tests were performed to investigate any significant difference between the 2 limbs preoperatively and postoperatively and within the injured limb before and after the surgical treatment. Statistical significance was set at P < .05. Results: The range of tibial rotation was higher in the ACL-deficient knee (12.6° ± 4.5°) than in the intact knee (7.9° ± 3.1°) preoperatively ( P < .05). The increased rotation was reduced in the reconstructed knee (8.9° ± 3.0°) after ACL reconstruction versus the intact knee postoperatively (8.2° ± 2.6°) ( P < .05). There was no significant difference in the tibial rotation between the intact knee and the reconstructed knee postoperatively ( P > .05). Conclusion: As assessed with a dynamic functional pivoting movement, the anatomic double-bundle ACL reconstruction successfully restores knee rotational stability from an impaired level.

The effectiveness of arthroscopic repair of type II superior labrum anterior–posterior lesion (SLAP) was unclear as previous studies examined this treatment with patients of combined types of SLAP lesions. To address this research gap, we evaluated the clinical and functional outcomes of arthroscopic repair for 16 patients (mean = 24.2, SD = 6.5) with clinical evidence of isolated type II SLAP lesion. After having arthroscopic stabilizations with Bioknotless suture anchors (Mitek), the patients were offered post-operative rehabilitation programs (e.g., physiotherapy) for 6 months. The symptoms of SLAP lesion and the functions of the shoulder were assessed pre-operatively and 28-month post-operatively by O’Brien test, Speed test, Yergason test, and University of California at Los Angeles rating for pain and function of the shoulder. Wilcoxon Signed Ranks test and McNemar test were employed to analyze the difference between assessment in pre-operation and post-operation phases. The result showed that patients’ shoulder functions improved (UCLA Shoulder Score), and symptoms of SLAP lesion reduced (O’Brien test, Speed test, and Yergason test) significantly (P < 0.05). Time for returning to play with pre-injury level was in average 9.4 months (range 4–24), and no complication or recurrence was detected. We concluded that arthroscopic repair is an effective operation of type II SLAP lesion with good clinical and functional outcomes; however, athletes with high demand of overhead throwing activities are likely to take longer duration of rehabilitation to attain full recovery.

This study presented a method to estimate the complete ground reaction forces from pressure insoles in walking. Five male subjects performed 10 walking trials in a laboratory. The complete ground reaction forces were collected during a right foot stride by a force plate at 1000 Hz. Simultaneous plantar pressure data were collected at 100 Hz by a pressure insole system with 99 sensors covering the whole plantar area. Stepwise linear regressions were performed to individually reconstruct the complete ground reaction forces in three directions from the 99 individual pressure data until redundancy among the predictors occurred. An additional linear regression was performed to reconstruct the vertical ground reaction force by the sum of the value of the 99 pressure sensors. Five other subjects performed the same walking test for validation. Estimated ground reaction forces in three directions were calculated with the developed regression models, and were compared with the real data recorded from force plate. Accuracy was represented by the correlation coefficient and the root mean square error. Results showed very good correlation in anterior-posterior (0.928) and vertical (0.989) directions, and reasonable correlation in medial-lateral direction (0.719). The root mean square error was about 12%, 5% and 28% of the peak recorded value. Future studies should aim to generalize the methods or to establish specific methods to other subjects, patients, motions, footwear and floor conditions. The method gives an extra option to study an estimation of the complete ground reaction forces in any environment without the constraints from the number and location of force plates.

Gout or pseudogout, caused by deposition of crystals, rarely affects the spine. We report 4 cases with gout or pseudogout in the lumbar spine. Two had cauda equina syndrome and another 2 had spinal stenosis. To avoid unnecessary surgery, this should be considered in the differential diagnosis when treating patients with histories of gout or pseudogout for spinal problems.

Two patients with Hoffa fracture of the knee, both suffering from poliomyelitis are reported. Both had unicondylar coronal plane fracture of the medial femoral condyle. The patients were treated with open reduction and screw fixation. Due to poor screw purchase, reoperation was necessary in one patient. The results were satisfactory in both patients.

Introduction With evolutions in surgical techniques, minimally invasive surgical (MIS) repair with Achillon applicator has been introduced. However, there is still a lack of literature to investigate into the clinical merits of MIS over open surgery. This study aims to investigate the correlation between clinical outcome, gait analysis and biomechanical properties comparing both surgical methods. Materials and methods A single centre retrospective review on all the consecutive operated patients between January 2004 and December 2008 was performed. Twenty-six patients (19 male and 7 female; age 40.4 ± 9.2 years) had experienced a complete Achilles tendon rupture with operative repair. Nineteen of the patients, 10 MIS versus 9 open repairs (13 men with a mean age of 40.54 ± 10.43 (range 23-62 yrs) and 6 women with a mean age of 45.33 ± 7.71 (range 35-57 yrs) were further invited to attend a thorough clinical assessment using Holz's scale and biomechanical evaluation at a mean of 25.3 months after operation. This study utilized the Cybex II isokinetic dynamometer to assess the isokinetic peak force of plantar-flexion and dorsiflexion of both ankles. The patients were also invited to return to our Gait Laboratory for analysis. The eight-infrared camera motion capture system (VICON, UK) was utilized for the acquisition of kinematic variables. Their anthropometric data was measured according to the Davis and coworkers' standard. Results The mean operative time and length of hospital stay were shorter in the MIS group. The operative time was 54.55 ± 15.15 minutes versus 68.80 ± 18.23 minutes of the MIS group and Open group respectively (p = 0.045), whereas length of stay was 3.36 ± 1.21 days versus 6.40 ± 3.70 days respectively (p = 0.039). There is statistically significant decrease (p = 0.005) in incision length in MIS group than the open surgery group, 3.23 ± 1.10 cm versus 9.64 ± 2.55 cm respectively. Both groups attained similar Holz's scores, 11.70 ± 0.95 versus 12.0 ± 1.50 respectively (p = 0.262). The mean percentage stance time of the injured leg for MIS patient was 58.44% while the mean percentage stance time of the injured leg for patients with open repair was 56.57%. T-test has shown there were no significance differences between the results of the two groups of patients. The loss of peak torque and total work done with respect to the injured side were similar between the MIS and open group. Discussion and conclusion MIS using Achillon method can achieve smaller incisions, shorter operative time and hospital stay. There is no statistical significance difference in clinical outcome, the stance time to strike time ratio and biomechanical properties on the leg receiving Achilles tendon repair using MIS method and open surgery.

This study investigated the ankle inversion and inversion velocity between various common motions in sports and simulated sprain motion, in order to provide a threshold for ankle sprain risk identification. The experiment was composed of two parts: firstly, ten male subjects wore a pair of sport shoes and performed ten trials of running, cutting, jump-landing and stepping-down motions. Secondly, five subjects performed five trials of simulated sprain motion by a supination sprain simulator. The motions were analyzed by an eight-camera motion capture system at 120 Hz. A force plate was employed to record the vertical ground reaction force and locate the foot strike time for common sporting motions. Ankle inversion and inversion velocity were calculated by a standard lower extremity biomechanics calculation procedure. Profiles of vertical ground reaction force, ankle inversion angle and ankle inversion velocity were obtained. Results suggested that the ankle was kept in an everted position during the stance. The maximum ankle inversion velocity ranged from 22.5 to 85.1 degrees/s and 114.0 to 202.5 degrees/s for the four tested motions and simulated sprain motion respectively. Together with the ankle inversion velocity reported in the injury case (623 degrees/s), a threshold of ankle inversion velocity of 300 degrees/s was suggested for the identification of ankle sprain. The information obtained in this study can serve as a basis for the development of an active protection apparatus for reducing ankle sprain injury.

Study Design A retrospective study was conducted to study the post operative upper limb palsy after laminoplasty for cervical myelopathy. Objective To identify a reliable and simple preoperative radiological parameter in predicting the risk of post operative upper limb palsy. Background Post operative upper limb palsy is one of the causes of patient dissatisfaction after surgery. There had been no simple, standard preoperative radiological parameters reliably predict the occurrence of this problem. Materials and methods Seventy-four patients received posterior cervical decompression from 1998 to 2008. Medical record and preoperative radiological information were evaluated. Clinical presentations of the palsy were described. The relationship between the occurrence of palsy and different preoperative radiological information is analyzed. Results Eighteen patients (24.3%) presented with post operative upper limb palsy. Majority of patients presented with dysesthesia (17/18) and with deficit of the C5 segment (17/18). Ten patients presented with pure dysesthesia and 8 patients presented with mixed motor-sensory deficit and dysesthesia. Multilevel involvement was exclusively presented in patients with motor weakness. A longer duration of symptom (16.7 Vs 57.2 days) was noticed in patients in the motor deficit group. Average Pavlov ratio less then 0.65 (P = 0.027, Odds Ratio = 3.68) and compression at the C3/4 in preoperative MRI image (P = 0.025, Odds Ratio = 6) were significant risk factors for development of this problem. Conclusion Post operative upper limb palsy is not uncommon and thorough preoperative explanation is important. There is a spectrum of clinical presentation and patients with multi-level involvement and motor deficit are associated with poorer prognosis. Average Pavlov ratio < 0.65 and compression at C3/4 segment on preoperative MRI image are simple and reliable preoperative predictor for the development of this problem.

Local anesthesia for knee arthroscopy is a well documented procedure with diagnostic and therapeutic role. Numerous therapeutic procedures including partial menisectomy, meniscus repair, abrasion chondroplasy, synovectomy, loose body removal can be performed safely and comfortably. Appropriate case selection, anesthetic strategy and technical expertise are the key to smooth and successful surgery.

This study presents a free-fall mechanical supination sprain simulator for evaluating the ankle joint kinematics during a simulated ankle supination sprain injury. The device allows the foot to be in an anatomical position before the sudden motion, and also allows different degrees of supination, or a combination of inversion and plantarflexion. Five subjects performed simulated supination sprain trials in five different supination angles. Ankle motion was captured by a motion analysis system, and the ankle kinematics were reported in plantarflexion/dorsiflexion, inversion/eversion and internal/external rotation planes. Results showed that all sprain motions were not pure single-plane motions but were accompanied by motion in other two planes, therefore, different degrees of supination were achieved. The presented sprain simulator allows a more comprehensive study of the kinematics of ankle sprain when compared with some previous laboratory research designs.

Background Excessive pronation (or eversion) at ankle joint in heel-toe running correlated with lower extremity overuse injuries. Orthotics and inserts are often prescribed to limit the pronation range to tackle the problem. Previous studies revealed that the effect is product-specific. This study investigated the effect of medial arch-heel support in inserts on reducing ankle eversion in standing, walking and running. Methods Thirteen pronators and 13 normal subjects participated in standing, walking and running trials in each of the following conditions: (1) barefoot, and shod condition with insert with (2) no, (3) low, (4) medium, and (5) high medial arch-heel support. Motions were captured and processed by an eight-camera motion capture system. Maximum ankle eversion was calculated by incorporating the raw coordinates of 15 anatomical positions to a self-compiled Matlab program with kinematics equations. Analysis of variance with repeated measures with post-hoc Tukey pairwise comparisons was performed on the data among the five walking conditions and the five running conditions separately. Results Results showed that the inserts with medial arch-heel support were effective in dynamics trials but not static trials. In walking, they successfully reduced the maximum eversion by 2.1 degrees in normal subjects and by 2.5–3.0 degrees in pronators. In running, the insert with low medial arch support significantly reduced maximum eversion angle by 3.6 and 3.1 degrees in normal subjects and pronators respectively. Conclusion Medial arch-heel support in inserts is effective in reducing ankle eversion in walking and running, but not in standing. In walking, there is a trend to bring the over-pronated feet of the pronators back to the normal eversion range. In running, it shows an effect to restore normal eversion range in 84% of the pronators.