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The effects of soft tissue lateral release on the stability of the ligament complex of the knee
(2020)
Purpose Valgus deformity presents a particular challenge in total knee arthroplasty. This condition regularly leads to contractures of the lateral capsular ligament complex and to overstretching of the medial ligamentous complex. Reconstruction of the knee joint kinematics and anatomy often requires lateral release. However, data on how such release weakens the stability of the knee are missing in the literature. This study investigated the effects of sequential lateral release on the collateral stability of the ligament complex of the knee in vitro. Methods Ten knee prostheses were implanted in 10 healthy cadaveric knee joints using a navigation device. Soft tissue lateral release consisted of five release steps, and stiffness and stability were determined at 0, 30, 60 and 90 degrees flexion after each step. Results Soft tissue lateral release increasingly weakened the ligament complex of the lateral compartment. Because of the large muscular parts, the release of the iliotibial band and the M. popliteus had little effect on the stability of the lateral and medial compartment, but release of the lateral ligament significantly decreased the stability in the lateral compartment over the entire range of motion. Stability in the medial compartment was hardly affected. Conversely, further release of the posterolateral capsule and the posterior cruciate ligament led to the loss of stability in the lateral compartment only in deep flexion, whereas stability decreased significantly in the medial compartment. Conclusion Our study shows for the first time the association between sequential lateral release and stability of the ligamentous complex of the knee. To maintain the stability, knee surgeons should avoid releasing the entire lateral collateral ligament, which would significantly decrease stability in the lateral compartment.
Purpose To investigate the influence of sacral slope on the correlation between measurements of lumbar lordosis obtained by standing radiographs and magnetic resonance images in supine position (MRI). Little information is available on the correlation between measurements of lumbar lordosis obtained by radiographic and MR images. Most relevant studies have shown correlations for the thoracic spine, but detailed analyses on the lumbar spine are lacking. Methods MR images and standing lateral radiographs of 63 patients without actual low back pain or radiographic pathologies of the lumbar spine were analyzed. Standing radiographic measurements included the sagittal parameters pelvic incidence (PI) pelvic tilt (PT), and sacral slope (SS); MR images were used to additionally measure lumbar L1-S1 lordosis and single level lordosis. Differences between radiographic and MRI measurements were analyzed and divided into 4 subgroups of different sacral slope according to Roussouly's classification. Results Global lumbar lordosis (L1-S1) was 44.99 degrees (+/- 10 754) on radiographs and 47.91 degrees (+/- 9.170) on MRI, yielding a clinically relevant correlation (r = 0.61, p < 0.01). Measurements of single level lordosis only showed minor differences. At all levels except for L5/S1, lordosis measured by means of standing radiographs was higher than that measured by MRI. The difference in global lumbar L1-S1 lordosis was -2.9 degrees. Analysis of the Roussouly groups showed the largest difference for L1-S1 (-8.3 degrees) in group 2. In group 4, when measured on MRI, L5/S1 lordosis (25.71 degrees) was lower than L4/L5 lordosis (27.63 degrees) compared to the other groups. Conclusions Although measurements of global lumbar lordosis significantly differed between the two scanning technologies, the mean difference was just 2.9 degrees. MRI in supine position may be used for estimating global lumbar lordosis, but single level lordosis should be determined by means of standing radiographs.
A key requirement in both native knee joints and total knee arthroplasty is a stable capsular ligament complex. However, knee stability is highly individual and ranges from clinically loose to tight. So far, hardly any in vivo data on the intrinsic mechanical of the knee are available. This study investigated if stiffness of the native ligament complex may be determined in vivo using a standard knee balancer. Measurements were obtained with a commercially available knee balancer, which was initially calibrated in vitro. 5 patients underwent reconstruction of the force-displacement curves of the ligament complex. Stiffness of the medial and lateral compartments were calculated to measure the stability of the capsular ligament complex. All force-displacement curves consisted of a non-linear section at the beginning and of a linear section from about 80 N onwards. The medial compartment showed values of 28.4 ± 1.2 N/mm for minimum stiffness and of 39.9 ± 1.1 N/mm for maximum stiffness; the respective values for the lateral compartment were 19.9 ± 0.9 N/mm and 46.6 ± 0.8 N/mm. A commercially available knee balancer may be calibrated for measuring stiffness of knee ligament complex in vivo, which may contribute to a better understanding of the intrinsic mechanical behaviour of knee joints.
Introduction Because of the ongoing discussion of imageless navigation in total knee arthroplasty (TKA), its advantages and disadvantages were evaluated in a large patient cohort. Methods This retrospective analysis included 2464 patients who had undergone TKA at a high-volume university arthroplasty center between 2012 and 2017. Navigated and conventional TKA were compared regarding postoperative mechanical axis, surgery duration, complication rates, one-year postoperative patient-reported outcome measures (PROMs) (WOMAC and EQ-5D indices), and responder rates as defined by the criteria of the Outcome Measures in Rheumatology and Osteoarthritis Research Society International consensus (OMERACT-OARSI). Results Both navigated (1.8 +/- 1.6 degrees) and conventional TKA (2.1 +/- 1.6 degrees, p = 0.002) enabled the exact reconstruction of mechanical axis. Surgery duration was six minutes longer for navigated TKA than for conventional TKA (p < 0.001). Complication rates were low in both groups with comparable frequencies: neurological deficits (p = 0.39), joint infection (p = 0.42 and thromboembolic events (p = 0.03). Periprosthetic fractures occurred more frequently during conventional TKA (p = 0.001). One-year PROMs showed excellent improvement in both groups. The WOMAC index was statistically higher for navigated TKA than for conventional TKA (74.7 +/- 19.0 vs. 71.7 +/- 20.7, p = 0.014), but the increase was not clinically relevant. Both groups had a similarly high EQ-5D index (0.23 +/- 0.24 vs. 0.26 +/- 0.25, p = 0.11) and responder rate (86.5% [256/296] vs. 85.9% [981/1142], p = 0.92). Conclusion Both methods enable accurate postoperative leg alignment with low complication rates and equally successful PROMs and responder rates one year postoperatively.
Weakening of the knee ligament complex due to sequential medial release in total knee arthroplasty
(2019)
PurposeThe purpose of this study was to investigate the effects of sequential medial release on the stiffness and collateral stability of the ligament complex of the knee. Irrespective of the implantation technique used, varus deformity frequently requires release of the capsular ligament complex. Yet, no data are available on how stiffness and stability of the knee ligament complex are weakened by such release.MethodsAfter total knee arthroplasty, ten healthy Thiel-fixed knee joints were subjected to sequential medial release consisting of six release steps. After each step, stiffness and stability were determined at 0 degrees, 30 degrees, 60 degrees, and 90 degrees.ResultsSequential medial release increasingly weakened the ligament complex. In extension, release of the anteromedial tibial sleeve 4cm below the joint line already weakened the ligament complex by approximately 13%. Release 6cm below the joint line reduced stiffness and stability by 15-20% over the entire range of motion. After detachment of the medial collateral ligament, stability was only about 60% of its initial value.ConclusionOur study showed for the first time the association between medial release and stiffness and stability of the knee ligament complex. To maintain stability, vigorous detachment of the knee ligament complex should be avoided. Release of the anteromedial tibial sleeve already initiates loss of stability. The main stabiliser is the medial ligament, which should never be completely detached.Level of evidenceIV.
Postural Stability and Pedobarography After Reconstruction of Peroneus Brevis Tendon Split Lesion
(2024)
Purpose
Lesions of the peroneal tendons are frequently overseen after ankle sprain. The symptoms consist of stress-dependent pain that extends from the inframalleolar to the proximal part along the course of the peroneal tendons as well as ankle instability and soft-tissue swelling. In case of unsuccessful conservative treatment, surgical therapy is recommended. The aim of the study was to evaluate the clinical and functional outcome after open reconstruction of the peroneus brevis tendon.
Methods
13 patients were included in this retrospective study. All of them received a single reconstruction of the peroneus brevis tendon in open technique. Postoperative results were evaluated with the AOFAS score, a functional and perdobargraphic analysis as well as measuring postural stability with the Biodex balance system. The participants were matched with a healthy control group according to age, sex and BMI.
Results
The results of the AOFAS score showed significantly convincing results in all subscores postoperatively. A bilateral comparison of the postural stability showed that the affected side had become functionally similar to the healthy side. No statistical significant difference was detected concerning both one-legged and two-legged standing with the control group. Pedobarographic results revealed no difference between the affected and contralateral side, as well as between the patients and the healthy control group.
Conclusion
Open reconstruction of the peroneus brevis tendon leads to significant better postoperative results and can be recommended after unsuccessful conservative treatment as promising option.
Idiopathic scoliosis is the largest group of all forms of scoliosis in the growth phase accounting for 80-90%. A distinction is made between idiopathic infantile (0-3 years), juvenile (4-10 years) and adolescent scoliosis (>10 years), depending on the age when scoliosis appears. The treatment depends on the skeletal age, the Cobb angle and the progression behavior of scoliosis. Mild cases are treated conservatively using physiotherapy, exercises and bracing but in advanced stages scoliosis should be surgically treated. With existing growth potential various techniques, such as traditional growing rods, magnetically controlled growth rods and vertebral body tethering are available. After the end of the growth phase a fusion should be recommended for scoliosis >50 degrees.
