There are over ½ million total knee replacement (TKR) procedures performed each year in the United States and is projected to increase to over 3.48 million by 2030. Concurrent with the increase in TKR procedures is a trend of younger patients receiving knee implants (under the age of 65). These younger patients are known to have a 5% lower implant survival rate at 8 years post-op compared to older patients (65+ years), and they are also known to live more active lifestyles that place higher demands on the durability and functional performance of the TKR device. Conventional TKR designs increase articular conformity to increase stability, but these articular constraints decrease patient range of knee motion, often limiting key measures of femoral rollback, A/P motion, and deep knee flexion. Without this articular constraint however, many patients report TKR “instability” during activities such as walking and stair descent, which can significantly impede confidence of movement. Therefore, there is a need for a TKR system that can offer enhanced stability while also maintaining active ranges of motion. A novel knee arthroplasty system has been designed that uses synthetic ligament systems that can be surgically replaced, to provide ligamentous stability and natural motion to increase the functional performance of the implant. A computational anatomical model (AnyBody) was developed that incorporated ligaments into an existing Journey II TKR. Ligaments were modeled and given biomechanical properties from literature. Simulated A/P drawer tests and knee flexion were analyzed for 2,916 possible cruciate ligament location and length combinations to determine the effects on the A/P stability of the TKR. A physical model was then constructed, and the design was verified by performing 110 N A/P drawer tests under 710 N of simulated body weight.Introduction
Materials and Methods
There are over one-half million total knee replacement (TKR) procedures performed each year in the United States and is projected to increase to over 3.48 million by 2030. Concurrent with the increase in TKR procedures is a trend of younger patients receiving knee implants (under the age of 65). These younger patients are known to have a 5% lower implant survival rate at 8 years post-op compared to older patients (65+ years), and they are also known to live more active lifestyles that place higher demands on the durability and functional performance of the TKR device. Conventional TKR designs increase articular conformity to increase stability, but these articular constraints decrease patient range of knee motion, often limiting key measures of femoral rollback, A/P motion, and deep knee flexion. Without this articular constraint however, many patients report TKR “instability” during activities such as walking and stair descent, which can significantly impede confidence of movement. Therefore there is a need for a TKR system that can offer enhanced stability while also maintaining active ranges of motion. A novel knee arthroplasty system was designed that uses synthetic ligament systems that can be surgically replaced, to provide ligamentous stability and natural motion to increase the functional performance of the implant. Using an anatomical knee model from the AnyBody software, a computational model that incorporated ligaments into an existing Journey II TKR was developed. Using the software ligaments were modeled and given biomechanical properties developed from equations from literature. Simulated A/P drawer tests and knee flexion test were analyzed for 2,916 possible cruciate ligament location and length combinations to determine the effects on the A/P stability of the TKR. A physical model was constructed, and the design was verified by performing 110 N A/P drawer tests under 710 N of simulated body weight.Introduction
Materials and Methods
We aimed to examine the characteristics of deep venous flow in
the leg in a cast and the effects of a wearable neuromuscular stimulator
(geko; FirstKind Ltd) and also to explore the participants’ tolerance
of the stimulator. This is an open-label physiological study on ten healthy volunteers.
Duplex ultrasonography of the superficial femoral vein measured
normal flow and cross-sectional area in the standing and supine
positions (with the lower limb initially horizontal and then elevated).
Flow measurements were repeated during activation of the geko stimulator
placed over the peroneal nerve. The process was repeated after the
application of a below-knee cast. Participants evaluated discomfort
using a questionnaire (verbal rating score) and a scoring index
(visual analogue scale).Objectives
Methods
The aim of this study was to perform a comprehensive evaluation of the changes in function from pre- to post-surgery in total and unilateral knee arthroplasty (UKA/TKA) patients. Twenty healthy (age 62.4 ±5.9, 11 male), 14 UKA (age 60.9 ±10.1, 8 male) and 17 TKA (age 67.2 ±8.1, 9 male) patients were studied. KA patients were assessed four weeks pre- and six months post-operation. Measures of perceived pain and function were collected using Oxford Knee Score (OKS) questionnaire. Tests of objective function included joint range of motion (RoM), ultrasound imaging, and 3-D motion analysis/inverse modelling from gait and sit-stand. An optimal set of variables was used to classify KA function using the Cardiff DST method. Pre-KA and healthy individuals were accurately classified (96%). Post-operation questionnaire measures of function improved for both UKA and TKA groups. However, observed measures of RoM, muscle atrophy and gait had only limited gains. This resulted in 57% of UKA and only 27% of TKA patients being classified as healthy post-operation. The results of this study show that 6 months post-surgery UKA patients had higher function than TKA. Using statistical approaches to combine functional assessments has provided an accurate platform to classify function and estimate changes from pre- to post-surgery. The clinical application of this tool requires further investigation and comparison to commonly used clinical techniques.
We systematically reviewed all the evidence published
in the English language on proximal interphalangeal joint (PIPJ)
replacement, to determine its effectiveness on the function of the
hand and the associated post-operative complications. Original studies were selected if they reported clinical outcome
with a minimum of one year’s follow-up. Quality was assessed using
the Cowley systematic review criteria modified for finger-joint
replacements. Of 319 articles identified, only five were adequately
reported according to our quality criteria; there were no randomised
controlled trials. PIPJ replacements had a substantial effect size
on hand pain of -23.2 (95% confidence interval (CI) -27.3 to -19.1)
and grip strength 1.2 (95% CI -10.7 to 13.1), and a small effect
on range of movement 0.2 (95% CI -0.4 to 0.8). A dorsal approach
was most successful. Post-operative loosening occurred in 10% (95%
CI 3 to 30) of ceramic and 12.5% (95% CI 7 to 21) of pyrocarbon
replacements. Post-operative complications occurred in 27.8% (95%
CI 20 to 37). We conclude that the effectiveness of PIPJ replacement has not
been established. Small observational case studies and short-term
follow-up, together with insufficient reporting of patient data,
functional outcomes and complications, limit the value of current
evidence. We recommend that a defined core set of patients, surgical and
outcome data for this intervention be routinely and systematically
collected within the framework of a joint registry.
Anterior Cruciate Ligament Reconstruction is a commonly performed orthopaedic operation. The use of a four-strand semitendinosus and gracilis hamstring graft (STG) is a well established method of reconstruction to restore knee stability. To assess the ten year subjective knee function and activity level following STG anterior cruciate ligament reconstruction.Background
Aim
Anterior cruciate ligament (ACL) reconstruction is a commonly performed operation. A variety of graft options are used with the most popular being bone-patellar-tendon-bone and hamstring autograft. There has been an increase in the popularity of hamstring autograft over the past decade. The aim of the study was to assess the ten year subjective knee function and activity level following four-strand semitendinosis and gracilis (STG) anterior cruciate ligament reconstruction. 86 patients underwent anterior cruciate reconstruction by two knee surgeons over a 12 month period (January 1999 to December 1999). 80 patients meet the inclusion criteria of arthroscopic ACL reconstruction. The same surgical technique was used by both surgeons involving four-strand STG autograft, single femoral and tibial tunnels and aperture graft fixation with the Round headed Cannulated Interference (RCI) screw. Patient evaluation was by completion of a Lysholm Knee Score and Tegner Activity Level Scale at a minimum of ten years from reconstructive surgery. This was by initial postal questionnaire and subsequent telephone follow-up. 80 patients underwent anterior cruciate reconstruction with average age 30.9 years (15 to 58 years). There was a 77.5% (62 patients) response at ten years to the questionnaire. The median Lysholm Knee Score at ten years was 94 (52 to 100). The median activity level had decreased from 9 to 5 at ten years according to the Tegner Activity Scale. 73% of patients reported a good or excellent outcome on the Lysholm score. The group of patients was further divided into those that required meniscal surgery and those that did not. The patients that did not require meniscal surgery had a median Lysholm score of 94 and those that required meniscal surgery had a similar median Lysholm score of 92.5. However it was noted that 8 patients required medial and lateral partial menisectomies at the time of original reconstruction. This group of patients had a median Lysholm Knee Score of 83.5 and Tegner Activity Scale of 4 at ten years following reconstruction. 17 of the 62 patients (27.4%) required re-operation because of further knee symptoms, with 4 patients requiring revision of the anterior cruciate following re-rupture. In conclusion anterior cruciate ligament reconstruction with four-strand STG hamstring autograft provides a reliable method of restoring knee function, with a 6% revision rate for re-rupture at ten years. Combined partial medial and lateral menisectomy at the time of the initial reconstruction is a poor prognostic indicator of function at ten years.
