We investigated the role of a functional brace worn for four months in the treatment of patients with an acute isolated tear of the posterior cruciate ligament to determine whether reduction of the posterior tibial translation during the healing period would give an improved final position of the tibia. The initial and follow-up stability was tested by Rolimeter arthrometry and radiography. The clinical outcome was evaluated using the Lysholm score, the Tegner score and the International Knee Documentation Committee scoring system at follow-up at one and two years. In all, 21 patients were studied, 21 of whom had completed one-year and 17 a two-year follow-up. The initial mean posterior sag (Rolimeter measurement) of 7.1 mm (5 to 10) was significantly reduced after 12 months to a mean of 2.3 mm (0 to 6, p <
0.001) and to a mean of 3.2 mm (2 to 7, p = 0.001) after 24 months. Radiological measurement gave similar results. The mean pre-injury Lysholm score was normal at 98 (95 to 100). At follow-up, a slight decrease in the mean values was observed to 94.0 (79 to 100, p = 0.001) at one year and 94.0 (88 to 100, p = 0.027, at two years). We concluded that the posterior cruciate ligament has an intrinsic healing capacity and, if the posteriorly translated tibia is reduced to a physiological position, it can heal with less attentuation. The applied treatment produces a good to excellent functional result.
There are several methods for evaluating stability
of the joint during total knee replacement (TKR). Activities of daily
living demand mechanical loading to the knee joint, not only in
full extension, but also in mid-flexion. The purpose of this study
was to compare the varus-valgus stability throughout flexion in
knees treated with either cruciate-retaining or posterior-stabilised
TKR, using an intra-operative navigation technique. A total of 34
knees underwent TKR with computer navigation, during which the investigator
applied a maximum varus-valgus stress to the knee while steadily
moving the leg from full extension to flexion both before and after
prosthetic implantation. The femorotibial angle was measured simultaneously
by the navigation system at every 10° throughout the range of movement.
It was found that posterior-stabilised knees had more varus-valgus
laxity than cruciate-retaining knees at all angles examined, and
the differences were statistically significant at 10° (p = 0.0093),
20° (p = 0.0098) and 30° of flexion (p = 0.0252). Cite this article:
The understanding of rotational alignment of the distal femur is essential in total knee replacement to ensure that there is correct placement of the femoral component. Many reference axes have been described, but there is still disagreement about their value and mutual angular relationship. Our aim was to validate a geometrically-defined reference axis against which the surface-derived axes could be compared in the axial plane. A total of 12 cadaver specimens underwent CT after rigid fixation of optical tracking devices to the femur and the tibia. Three-dimensional reconstructions were made to determine the anatomical surface points and geometrical references. The spatial relationships between the femur and tibia in full extension and in 90° of flexion were examined by an optical infrared tracking system. After co-ordinate transformation of the described anatomical points and geometrical references, the projection of the relevant axes in the axial plane of the femur were mathematically achieved. Inter- and intra-observer variability in the three-dimensional CT reconstructions revealed angular errors ranging from 0.16° to 1.15° for all axes except for the trochlear axis which had an interobserver error of 2°. With the knees in full extension, the femoral transverse axis, connecting the centres of the best matching spheres of the femoral condyles, almost coincided with the tibial transverse axis (mean difference −0.8°,
There are two techniques widely used to determine the rotational
alignment of the components in total knee arthroplasty (TKA); gap
balancing (GB) and measured resection (MR). Which technique is the
best remains controversial. We aimed to investigate this in a systematic
review and meta-analysis. In accordance with the methods of Cochrane, databases were searched
for all randomised controlled trials in the literature between January
1986 and June 2015 comparing radiographic and clinical outcomes
between the use of these two tecniques. Meta-analysis involved the
use of the Revman5.3 software provided by Cochrane collaboration.Aims
Materials and Methods
We have examined the relationship between the size of the flexion gap and the anterior translation of the tibia in flexion during implantation of a posterior cruciate ligament (PCL)-retaining BalanSys total knee replacement (TKR). In 91 knees, the flexion gap and anterior tibial translation were measured intra-operatively using a custom-made, flexible tensor-spacer device. The results showed that for each increase of 1 mm in the flexion gap in the tensed knee a mean anterior tibial translation of 1.25 mm (SD 0.79, 95% confidence interval 1.13 to 1.37) was produced. When implanting a PCL-retaining TKR the surgeon should be aware that the tibiofemoral contact point is related to the choice of thickness of the polyethylene insert. An additional thickness of polyethylene insert of 2 mm results in an approximate increase in tibial anterior translation of 2.5 mm while the flexed knee is distracted with a force of between 100 N and 200 N.
The success of total knee replacement (TKR) depends
on optimal soft-tissue balancing, among many other factors. The
objective of this study is to correlate post-operative anteroposterior
(AP) translation of a posterior cruciate ligament-retaining TKR
with clinical outcome at two years. In total 100 patients were divided
into three groups based on their AP translation as measured by the
KT-1000 arthrometer. Group 1 patients had AP translation <
5
mm, Group 2 had AP translation from 5 mm to 10 mm, and Group 3 had
AP translation >
10 mm. Outcome assessment included range of movement
of the knee, the presence of flexion contractures, hyperextension,
knee mechanical axes and functional outcome using the Knee Society
score, Oxford knee score and the Short-Form 36 questionnaire. At two years, patients in Group 2 reported significantly better
Oxford knee scores than the other groups (p = 0.045). A positive
correlation between range of movement and AP translation was noted,
with patients in group 3 having the greatest range of movement (mean
flexion: 117.9° (106° to 130°)) (p <
0.001). However, significantly
more patients in Group 3 developed hyperextension >
10° (p = 0.01). In this study, the best outcome for cruciate-ligament retaining
TKR was achieved in patients with an AP translation of 5 mm to 10
mm.
We evaluated the long-term outcome of isolated endoscopically-assisted posterior cruciate ligament reconstruction in 26 patients using hamstring tendon autografts after failure of conservative management. At ten years after surgery the mean International Knee Documentation Committee subjective knee score was 87 ( At ten years endoscopic reconstruction of the posterior cruciate ligament with hamstring tendon autograft is effective in reducing knee symptoms. Of the series, 22 patients underwent radiological assessment for the development of osteoarthritis using the Kellgren-Lawrence grading scale. In four patients, grade 2 changes with loss of joint space was observed and another four patients showed osteophyte formation with moderate joint space narrowing (grade 3). These findings compared favourably with non-operatively managed injuries of the posterior cruciate ligament. This procedure for symptomatic patients with posterior cruciate ligament laxity who have failed conservative management offers good results.
We evaluated the rates of survival and cause
of revision of seven different brands of cemented primary total
knee replacement (TKR) in the Norwegian Arthroplasty Register during
the years 1994 to 2009. Revision for any cause, including resurfacing
of the patella, was the primary endpoint. Specific causes of revision
were secondary outcomes. Three posterior cruciate-retaining (PCR) fixed modular-bearing
TKRs, two fixed non-modular bearing PCR TKRs and two mobile-bearing
posterior cruciate-sacrificing TKRs were investigated in a total
of 17 782 primary TKRs. The median follow-up for the implants ranged
from 1.8 to 6.9 years. Kaplan-Meier 10-year survival ranged from
89.5% to 95.3%. Cox’s relative risk (RR) was calculated relative
to the fixed modular-bearing Profix knee (the most frequently used
TKR in Norway), and ranged from 1.1 to 2.6. The risk of revision
for aseptic tibial loosening was higher in the mobile-bearing LCS
Classic (RR 6.8 (95% confidence interval (CI) 3.8 to 12.1)), the
LCS Complete (RR 7.7 (95% CI 4.1 to 14.4)), the fixed modular-bearing
Duracon (RR 4.5 (95% CI 1.8 to 11.1)) and the fixed non-modular
bearing AGC Universal TKR (RR 2.5 (95% CI 1.3 to 5.1)), compared
with the Profix. These implants (except AGC Universal) also had
an increased risk of revision for femoral loosening (RR 2.3
(95% CI 1.1 to 4.8), RR 3.7 (95% CI 1.6 to 8.9), and RR 3.4 (95%
CI 1.1 to 11.0), respectively). These results suggest that aseptic
loosening is related to design in TKR. Cite this article:
We report a retrospective analysis of the results of combined arthroscopically-assisted posterior cruciate ligament reconstruction and open reconstruction of the posterolateral corner in 19 patients with chronic (three or more months) symptomatic instability and pain in the knee. All the operations were performed between 1996 and 2003 and all the patients were assessed pre- and post-operatively by physical examination and by applying three different ligament rating scores. All also had weight-bearing radiographs, MR scans and an examination under anaesthesia and arthroscopy pre-operatively. The posterior cruciate ligament reconstruction was performed using an arthroscopically-assisted single anterolateral bundle technique and the posterolateral corner structures were reconstructed using an open Larson type of tenodesis. The mean follow up was 66.8 months (24 to 110). Pre-operatively, all the patients had a grade III posterior sag according to Clancy and demonstrated more than 20° of external rotation compared with the opposite normal knee on the Dial test. Post-operatively, seven patients (37%) had no residual posterior sag, 11 (58%) had a grade I posterior sag and one (5%) had a grade II posterior sag. In five patients (26%) there was persistent minimal posterolateral laxity. The Lysholm score improved from a mean of 41.2 (28 to 53) to 76.5 (57 to 100) (p = 0.0001) and the Tegner score from a mean of 2.6 (1 to 4) to 6.4 (4 to 9) (p = 0.0001). We conclude that while a combined reconstruction of chronic posterior cruciate ligament and posterolateral corner instability improves the function of the knee, it does not restore complete stability.
Bicruciate-stabilised total knee replacement (TKR) aims to restore normal kinematics by replicating the function of both cruciate ligaments. We performed a prospective, randomised controlled trial in which bicruciate- and posterior-stabilised TKRs were implanted in 13 and 15 osteo-arthritic knees, respectively. The mean age of the bicruciate-stabilised group was 63.9 years ( At near full extension during step-up, the bicruciate-stabilised TKR produced a higher mean PTA than the posterior-stabilised TKR, indicating that the bicruciate design at least partially restored the kinematic role of the anterior cruciate ligament. The bicruciate-stabilised TKR largely restored the pre-operative kinematics, whereas the posterior-stabilised TKR resulted in a consistently lower PTA at all activities. The PTA in the pre-operative knees was higher than in the control group during the step-up and at near full knee extension. Overall, both groups generated a more normal PTA than that seen in previous studies in high knee flexion. This suggested that both designs of TKR were more effective at replicating the kinematic role of the posterior cruciate ligament than those used in previous studies.
The aim of this prospective multicentre study
was to report the patient satisfaction after total knee replacement (TKR),
undertaken with the aid of intra-operative sensors, and to compare
these results with previous studies. A total of 135 patients undergoing
TKR were included in the study. The soft-tissue balance of each
TKR was quantified intra-operatively by the sensor, and 18 (13%)
were found to be unbalanced. A total of 113 patients (96.7%) in
the balanced group and 15 (82.1%) in the unbalanced group were satisfied
or very satisfied one year post-operatively (p = 0.043). A review of the literature identified no previous study with
a mean level of satisfaction that was greater than the reported
level of satisfaction of the balanced TKR group in this study. Ensuring
soft-tissue balance by using intra-operative sensors during TKR
may improve satisfaction. Cite this article:
Instability is a common indication for early
revision after both primary and revision total knee arthroplasty
(TKA), accounting for up to 20% in the literature. The number of
TKAs performed annually continues to climb exponentially, thus having
an effective algorithm for treatment is essential. This relies on
a thorough pre- and intra-operative assessment of the patient. The
underlying cause of the instability must be identified initially
and subsequently, the surgeon must be able to balance the flexion
and extension gaps and be comfortable using a variety of constrained
implants. This review describes the assessment of the unstable TKA, and
the authors’ preferred form of treatment for these difficult cases
where the source of instability is often multifactorial. Cite this article:
Animal studies have shown that implanted anterior cruciate ligament (ACL) grafts initially undergo a process of revascularisation prior to remodelling, ultimately increasing mechanical strength. We investigated whether minimal debridement of the intercondylar notch and the residual stump of the ruptured ACL leads to earlier revascularisation in ACL reconstruction in humans. We undertook a randomised controlled clinical trial in which 49 patients underwent ACL reconstruction using autologous four-strand hamstring tendon grafts. Randomised by the use of sealed envelopes, 25 patients had a conventional clearance of the intercondylar notch and 24 had a minimal debridement method. Three patients were excluded from the study. All patients underwent MR scanning postoperatively at 2, 6 and 12 months, together with clinical assessment using a KT-1000 arthrometer and International Knee Documentation Committee (IKDC) evaluation. All observations were made by investigators blinded to the surgical technique. Signal intensity was measured in 4 mm diameter regions of interest along the ACL graft and the mid-substance of the posterior cruciate ligament. Our results indicate that minimal debridement leads to earlier revascularisation within the mid-substance of the ACL graft at two months (paired
We performed a prospective, randomised trial of 44 patients to compare the functional outcomes of a posterior-cruciate-ligament-retaining and posterior-cruciate-ligament-substituting total knee arthroplasty, and to gain a better understanding of the At follow-up at five years, no statistically significant differences were found in the clinical outcome measurements for either design. The prevalence of radiolucent lines and the survivorship were the same. In a subgroup of 15 knees, additional image-intensifier analysis in the horizontal and sagittal planes was performed during step-up and lunge activity. Our analysis revealed striking differences. Lunge activity showed a mean posterior displacement of both medial and lateral tibiofemoral contact areas (roll-back) which was greater and more consistent in the cruciate-substituting than in the cruciate-retaining group (medial p <
0.0001, lateral p = 0.011). The amount of posterior displacement could predict the maximum flexion which could be achieved (p = 0.018). Forward displacement of the tibiofemoral contact area in flexion during stair activity was seen more in the cruciate-retaining than in the cruciate-substituting group. This was attributed mainly to insufficiency of the posterior cruciate ligament and partially to that of the anterior cruciate ligament. We concluded that, despite similar clinical outcomes, there are significant kinematic differences between cruciate-retaining and cruciate-substituting arthroplasties.
We retrospectively reviewed the hospital records of 68 patients who had been referred with an injury to the posterolateral corner of the knee to a specialist knee surgeon between 2005 and 2009. These injuries were diagnosed based on a combination of clinical testing and imaging and arthroscopy when available. In all, 51 patients (75%) presented within 24 hours of their injury with a mean presentation at eight days (0 to 20) after the injury. A total of 63 patients (93%) had instability of the knee at presentation. There was a mean delay to the diagnosis of injury to the posterolateral corner of 30 months (0 to 420) from the time of injury. In all, the injuries in 49 patients (72%) were not identified at the time of the initial presentation, with the injury to the posterolateral corner only recognised in those patients who had severe multiple ligamentous injuries. The correct diagnosis, including injury to the posterolateral corner, had only been made in 34 patients (50%) at time of referral to a specialist knee clinic. MRI correctly identified 14 of 15 injuries when performed acutely (within 12 weeks of injury), but this was the case in only four of 15 patients in whom it was performed more than 12 weeks after the injury. Our study highlights a need for greater diligence in the examination and investigation of acute ligamentous injuries at the knee with symptoms of instability, in order to avoid failure to identify the true extent of the injury at the time when anatomical repair is most straightforward.
Abnormal sagittal kinematics after total knee replacement (TKR) can adversely affect functional outcome. Two important determinants of knee kinematics are component geometry and the presence or absence of a posterior-stabilising mechanism (cam-post). We investigated the influence of these variables by comparing the kinematics of a TKR with a polyradial femur with a single radius design, both with and without a cam-post mechanism. We assessed 55 patients, subdivided into four groups, who had undergone a TKR one year earlier by using an established fluoroscopy protocol in order to examine their kinematics
Coronal plane fractures of the posterior femoral
condyle, also known as Hoffa fractures, are rare. Lateral fractures are
three times more common than medial fractures, although the reason
for this is not clear. The exact mechanism of injury is likely to
be a vertical shear force on the posterior femoral condyle with
varying degrees of knee flexion. These fractures are commonly associated
with high-energy trauma and are a diagnostic and surgical challenge. Hoffa
fractures are often associated with inter- or supracondylar distal
femoral fractures and CT scans are useful in delineating the coronal
shear component, which can easily be missed. There are few recommendations
in the literature regarding the surgical approach and methods of
fixation that may be used for this injury. Non-operative treatment
has been associated with poor outcomes. The goals of treatment are
anatomical reduction of the articular surface with rigid, stable
fixation to allow early mobilisation in order to restore function.
A surgical approach that allows access to the posterior aspect of
the femoral condyle is described and the use of postero-anterior
lag screws with or without an additional buttress plate for fixation
of these difficult fractures. Cite this article:
Injury to the common peroneal nerve was present in 14 of 55 patients (25%) with dislocation of the knee. All underwent ligament reconstruction. The most common presenting direction of the dislocation was anterior or anteromedial with associated disruption of both cruciate ligaments and the posterolateral structures of the knee. Palsy of the common peroneal nerve was present in 14 of 34 (41%) of these patients. Complete rupture of the nerve was seen in four patients and a lesion in continuity in ten. Three patients with lesions in continuity, but with less than 7 cm of the nerve involved, had complete recovery within six to 18 months. In the remaining seven with more extensive lesions, two regained no motor function, and one had only MRC grade-2 function. Four patients regained some weak dorsiflexion or eversion (MRC grade 3 or 4). Some sensory recovery occurred in all seven of these patients, but was incomplete. In summary, complete recovery occurred in three (21%) and partial recovery of useful motor function in four (29%). In the other seven (50%) no useful motor or sensory function returned.
This retrospective study evaluated the midterm clinical and radiographic outcomes of a second-generation total knee replacement system. In a multicentre consecutive series of 1512 patients, 1970 knees were treated with the PFC Sigma knee system (Depuy, Warsaw, Indiana). The patients were reviewed for functional outcome, and underwent independent radiographic evaluation at a mean follow-up of 7.3 years (5 to 10). A total of 40 knees (2%) required revision, 17 (0.9%) for infection. The incidence of osteolysis was 2.2%. The ten-year survival with revision for any cause other than infection as the endpoint was 97.2% (95% CI 95.4 to 99.1). The PFC Sigma knee system appears to provide excellent results in the medium term.