Aims. This study aims to evaluate a new home medical
Mid-level constraint designs for total knee arthroplasty (TKA) are intended to reduce coronal plane laxity. Our aims were to compare kinematics and ligament forces of the Zimmer Biomet Persona posterior-stabilized (PS) and mid-level designs in the coronal, sagittal, and axial planes under loads simulating clinical exams of the knee in a cadaver model. We performed TKA on eight cadaveric knees and loaded them using a robotic manipulator. We tested both PS and mid-level designs under loads simulating clinical exams via applied varus and valgus moments, internal-external (IE) rotation moments, and anteroposterior forces at 0°, 30°, and 90° of flexion. We measured the resulting tibiofemoral angulations and translations. We also quantified the forces carried by the medial and lateral collateral ligaments (MCL/LCL) via serial sectioning of these structures and use of the principle of superposition.Aims
Methods
Outcomes of current operative treatments for arthrofibrosis after total knee arthroplasty (TKA) are not consistently positive or predictable. Pharmacological in vivo studies have focused mostly on prevention of arthrofibrosis. This study used a rabbit model to evaluate intra-articular (IA) effects of celecoxib in treating contracted knees alone, or in combination with capsular release. A total of 24 rabbits underwent contracture-forming surgery with knee immobilization followed by remobilization surgery at eight weeks. At remobilization, one cohort underwent capsular release (n = 12), while the other cohort did not (n = 12). Both groups were divided into two subcohorts (n = 6 each) – one receiving IA injections of celecoxib, and the other receiving injections of vehicle solution (injections every day for two weeks after remobilization). Passive extension angle (PEA) was assessed in live rabbits at 10, 16, and 24 weeks, and disarticulated limbs were analyzed for capsular stiffness at 24 weeks.Aims
Methods
Disruption of the extensor mechanism in total
knee arthroplasty may occur by tubercle avulsion, patellar or quadriceps
tendon rupture, or patella fracture, and whether occurring intra-operatively
or post-operatively can be difficult to manage and is associated
with a significant rate of failure and associated complications.
This surgery is frequently performed in compromised tissues, and
repairs must frequently be protected with cerclage wiring and/or
augmentation with local tendon (semi-tendinosis, gracilis) which
may also be used to treat soft-tissue loss in the face of chronic
disruption. Quadriceps rupture may be treated with conservative
therapy if the patient retains active extension. Component loosening
or loss of active extension of 20° or greater are clear indications
for surgical treatment of patellar fracture. Acute patellar tendon
disruption may be treated by primary repair. Chronic extensor failure
is often complicated by tissue loss and retraction can be treated
with medial gastrocnemius flaps, achilles tendon allografts, and
complete extensor mechanism allografts. Attention to fixing the
graft in full extension is mandatory to prevent severe extensor
lag as the graft
The aims of this study were to evaluate wear on the surface of cobalt-chromium (CoCr) femoral components used in total knee arthroplasty (TKA) and compare the wear of these components with that of ceramic femoral components. Optical profilometry was used to evaluate surface roughness and to examine the features created by the wear process in a knee wear simulator. We developed a method of measuring surface changes on five CoCr femoral components and quantifying the loss of material from the articular surface during the wear process. We also examined the articular surface of three ceramic femoral components from a previous test for evidence of surface damage, and compared it with that of CoCr components.Aims
Methods
Robotic-assisted total knee arthroplasty (RA-TKA) has been introduced to provide accurate bone cuts and help achieve the target knee alignment, along with symmetric gap balancing. The purpose of this study was to determine if any early clinical benefits could be realized following TKA using robotic-assisted technology. In all, 140 consecutive patients undergoing RA-TKA and 127 consecutive patients undergoing conventional TKA with minimum six-week follow-up were reviewed. Differences in visual analogue scores (VAS) for pain at rest and with activity, postoperative opiate usage, and length of stay (LOS) between the RA-TKA and conventional TKA groups were compared.Aims
Methods
The results of kinematic total knee arthroplasty (KTKA) have been reported in terms of limb and component alignment parameters but not in terms of gap laxities and differentials. In kinematic alignment (KA), balance should reflect the asymmetrical balance of the normal knee, not the classic rectangular flexion and extension gaps sought with gap-balanced mechanical axis total knee arthroplasty (MATKA). This paper aims to address the following questions: 1) what factors determine coronal joint congruence as measured on standing radiographs?; 2) is flexion gap asymmetry produced with KA?; 3) does lateral flexion gap laxity affect outcomes?; 4) is lateral flexion gap laxity associated with lateral extension gap laxity?; and 5) can consistent ligament balance be produced without releases? A total of 192 KTKAs completed by a single surgeon using a computer-assisted technique were followed for a mean of 3.5 years (2 to 5). There were 116 male patients (60%) and 76 female patients (40%) with a mean age of 65 years (48 to 88). Outcome measures included intraoperative gap laxity measurements and component positions, as well as joint angles from postoperative three-foot standing radiographs. Patient-reported outcome measures (PROMs) were analyzed in terms of alignment and balance: EuroQol (EQ)-5D visual analogue scale (VAS), Knee Injury and Osteoarthritis Outcome Score (KOOS), KOOS Joint Replacement (JR), and Oxford Knee Score (OKS).Aims
Patients and Methods
To compare the effect of femoral bone tunnel configuration on tendon-bone healing in an anterior cruciate ligament (ACL) reconstruction animal model. Anterior cruciate ligament reconstruction using the plantaris tendon as graft material was performed on both knees of 24 rabbits (48 knees) to mimic ACL reconstruction by two different suspensory fixation devices for graft fixation. For the adjustable fixation device model (Socket group; group S), a 5 mm deep socket was created in the lateral femoral condyle (LFC) of the right knee. For the fixed-loop model (Tunnel group; group T), a femoral tunnel penetrating the LFC was created in the left knee. Animals were sacrificed at four and eight weeks after surgery for histological evaluation and biomechanical testing.Objectives
Methods
In patients undergoing medial opening wedge high tibial osteotomy
(MOWHTO), soft tissue opening on the medial side of the knee is
difficult to predict. When the load bearing axis is corrected beyond
a certain point, the knee joint tilts open on the medial side. We
therefore hypothesised that there is a tipping point and defined
this as the coronal hypomochlion. In this prospective study of 150 navigated MOWHTOs (144 consecutive
patients), data were collected before surgery and at three months
post-operatively. In order to calculate the hypomochlion, we compared
the respective changes to the joint line convergence angle (JLCA)
with the post-operative axis of the leg. The change to the medial proximal
tibial angle accounts for only about 80% of the change to the femorotibial
angle; 20% of the correction can therefore be attributed to non-osseous,
soft-tissue changes.Aims
Patients and Methods
The term mid-flexion instability has entered
the orthopaedic literature as a concept, but has not been confirmed
as a distinct clinical entity. The term is used freely, sometimes
as a synonym for flexion instability. However, the terms need to
be clearly separated. A cadaver study published in 1990 associated
joint line elevation with decreased stability at many angles of
flexion, but that model was not typical of clinical scenarios. The
literature is considered and it is proposed that the more common
entity of an uncorrected flexion contracture after a measured resection arthroplasty
technique is more likely to produce clinical findings that suggest
instability mid-flexion. It is proposed that the clinical scenario encountered is generalised
instability, with the appearance of stability in full extension
from tight posterior structures. This paper seeks to clarify whether mid-flexion instability exists
as an entity distinct from other commonly recognised forms of instability. Cite this article:
The aim of this consensus was to develop a definition of post-operative
fibrosis of the knee. An international panel of experts took part in a formal consensus
process composed of a discussion phase and three Delphi rounds.Aims
Patients and Methods
The purpose of this study was to report the experience of dynamic
intraligamentary stabilisation (DIS) using the Ligamys device for
the treatment of acute ruptures of the anterior cruciate ligament
(ACL). Between March 2011 and April 2012, 50 patients (34 men and 16
women) with an acute rupture of the ACL underwent primary repair
using this device. The mean age of the patients was 30 years (18
to 50). Patients were evaluated for laxity, stability, range of
movement (ROM), Tegner, Lysholm, International Knee Documentation Committee
(IKDC) and visual analogue scale (VAS) scores over a follow-up period
of two years.Aims
Patients and Methods
To examine the rates of hamstring graft salvage with arthroscopic
debridement of infected anterior cruciate ligament (ACL) reconstruction
as reported in the literature and discuss functional outcomes. A search was performed without language restriction on PubMed,
EMBASE, Ovid, CINAHL and Cochrane Register of Controlled Trials
(CENTRAL) databases from their inception to April 2015. We identified
147 infected hamstring grafts across 16 included studies. Meta-analysis
was performed using a random-effects model to estimate the overall
graft salvage rate, incorporating two different definitions of graft
salvage.Aims
Materials and Methods
Seven stiff total knee arthroplasties are presented
to illustrate the roles of: 1) manipulation under general anesthesia;
2) multiple concurrent diagnoses in addition to stiffness; 3) extra-articular
pathology; 4) pain as part of the stiffness triad (pain and limits
to flexion or extension); 5) component internal rotation; 6) multifactorial
etiology; and 7) surgical exposure in this challenging clinical
problem.
Our aim was to assess the use of intra-operative fluoroscopy
in the assessment of the position of the tibial tunnel during reconstruction
of the anterior cruciate ligament (ACL). Between January and June 2009 a total of 31 arthroscopic hamstring
ACL reconstructions were performed. Intra-operative fluoroscopy
was introduced (when available) to verify the position of the guidewire
before tunnel reaming. It was only available for use in 20 cases,
due to other demands on the radiology department. The tourniquet
times were compared between the two groups and all cases where radiological
images lead to re-positioning of the guide wire were recorded. The
secondary outcome involved assessing the tibial interference screw
position measured on post-operative radiographs and comparing with
the known tunnel position as shown on intra-operative fluoroscopic
images.Objectives
Methods
Total knee replacement (TKR) smart tibial trials
have load-bearing sensors which will show quantitative compartment
pressure values and femoral-tibial tracking patterns. Without smart
trials, surgeons rely on feel and visual estimation of imbalance
to determine if the knee is optimally balanced. Corrective soft-tissue
releases are performed with minimal feedback as to what and how
much should be released. The smart tibial trials demonstrate graphically
where and how much imbalance is present, so that incremental releases
can be performed. The smart tibial trials now also incorporate accelerometers
which demonstrate the axial alignment. This now allows the surgeon
the option to perform a slight recut of the tibia or femur to provide
soft-tissue balance without performing soft-tissue releases. Using
a smart tibial trial to assist with soft-tissue releases or bone
re-cuts, improved patient outcomes have been demonstrated at one
year in a multicentre study of 135 patients (135 knees). Cite this article:
We used immediate post-operative The bending angles in the sagittal and axial planes were significantly
greater but the coronal-bending angle was significantly less in
the transtibial group than in the anteromedial portal and outside-in
groups (p <
0.001 each). The mean length of the femoral tunnel
in all three planes was significantly greater in the transtibial
group than the anteromedial portal and outside-in groups (p <
0.001 each), but all mean tunnel lengths in the three groups exceeded
30 mm. The only significant difference was the coronal graft- bending
angle in the anteromedial portal and outside-in groups (23.5° Compared with the transtibial technique, the anteromedial portal
and outside-in techniques may reduce the graft-bending stress at
the opening of the femoral tunnel. Despite the femoral tunnel length
being shorter in the anteromedial portal and outside-in techniques
than in the transtibial technique, a femoral tunnel length of more than
30 mm in the anteromedial portal and outside-in techniques may be
sufficient for the graft to heal. Cite this article:
The potential harm to the growth plate following reconstruction of the anterior cruciate ligament in skeletally-immature patients is well documented, but we are not aware of literature on the subject of the fate of the graft itself. We have reviewed five adolescent males who underwent reconstruction of the ligament with four-strand hamstring grafts using MR images taken at a mean of 34.6 months (18 to 58) from the time of operation. The changes in dimension of the graft were measured and compared with those taken at the original operation. No growth arrest was seen on radiological or clinical measurement of leg-length discrepancy, nor was there any soft-tissue contracture. All the patients regained their pre-injury level of activity, including elite-level sport in three. The patients grew by a mean of 17.3 cm (14 to 24). The diameter of the grafts did not change despite large increases in length (mean 42%; 33% to 57%). Most of the gain in length was on the femoral side. Large changes in the length of the grafts were seen. There is a considerable increase in the size of the graft, so some neogenesis must occur; the graft must grow.
Smart trials are total knee tibial trial liners
with load bearing and alignment sensors that will graphically show quantitative
compartment load-bearing forces and component track patterns. These
values will demonstrate asymmetrical ligament balancing and misalignments
with the medial retinaculum temporarily closed. Currently surgeons
use feel and visual estimation of imbalance to assess soft-tissue
balancing and tracking with the medial retinaculum open, which results
in lower medial compartment loads and a wider anteroposterior tibial
tracking pattern. The sensor trial will aid the total knee replacement
surgeon in performing soft-tissue balancing by providing quantitative
visual feedback of changes in forces while performing the releases
incrementally. Initial experience using a smart tibial trial is
presented.
We investigated whether an asymmetric extension
gap seen on routine post-operative radiographs after primary total
knee replacement (TKR) is associated with pain at three, six, 12
and 24 months’ follow-up. On radiographs of 277 patients after primary
TKR we measured the distance between the tibial tray and the femoral
condyle on both the medial and lateral sides. A difference was defined
as an asymmetric extension gap. We considered three groups (no asymmetric
gap, medial-opening and lateral-opening gap) and calculated the
associations with the Western Ontario and McMaster Universities
osteoarthritis index pain scores over time. Those with an asymmetric extension gap of ≥ 1.5 mm had a significant
association with pain scores at three months’ follow-up; patients
with a medial-opening extension gap reported more pain and patients
with a lateral-opening extension gap reported less pain (p = 0.036).
This effect was still significant at six months (p = 0.044), but had
lost significance by 12 months (p = 0.924). When adjusting for multiple
cofounders the improvement in pain was more pronounced in patients
with a lateral-opening extension gap than in those with a medial-opening extension
gap at three (p = 0.037) and six months’ (p = 0.027) follow-up. Cite this article:
