While mechanical alignment (MA) is the traditional technique in total knee arthroplasty (TKA), its potential for altering constitutional alignment remains poorly understood. This study aimed to quantify unintentional changes to constitutional coronal alignment and joint line obliquity (JLO) resulting from MA. A retrospective cohort study was undertaken of 700 primary MA TKAs (643 patients) performed between 2014 and 2017. Lateral distal femoral and medial proximal tibial angles were measured pre- and postoperatively to calculate the arithmetic hip-knee-ankle angle (aHKA), JLO, and Coronal Plane Alignment of the Knee (CPAK) phenotypes. The primary outcome was the magnitude and direction of aHKA, JLO, and CPAK alterations.Aims
Methods
Intraoperative pressure sensors allow surgeons to quantify soft-tissue balance during total knee arthroplasty (TKA). The aim of this study was to determine whether using sensors to achieve soft-tissue balance was more effective than manual balancing in improving outcomes in TKA. A multicentre randomized trial compared the outcomes of sensor balancing (SB) with manual balancing (MB) in 250 patients (285 TKAs). The primary outcome measure was the mean difference in the four Knee injury and Osteoarthritis Outcome Score subscales (ΔKOOS4) in the two groups, comparing the preoperative and two-year scores. Secondary outcomes included intraoperative balance data, additional patient-reported outcome measures (PROMs), and functional measures.Aims
Methods
It is unknown whether gap laxities measured in robotic arm-assisted total knee arthroplasty (TKA) correlate to load sensor measurements. The aim of this study was to determine whether symmetry of the maximum medial and lateral gaps in extension and flexion was predictive of knee balance in extension and flexion respectively using different maximum thresholds of intercompartmental load difference (ICLD) to define balance. A prospective cohort study of 165 patients undergoing functionally-aligned TKA was performed (176 TKAs). With trial components in situ, medial and lateral extension and flexion gaps were measured using robotic navigation while applying valgus and varus forces. The ICLD between medial and lateral compartments was measured in extension and flexion with the load sensor. The null hypothesis was that stressed gap symmetry would not correlate directly with sensor-defined soft tissue balance.Aims
Methods
It is unknown whether kinematic alignment (KA) objectively improves knee balance in total knee arthroplasty (TKA), despite this being the biomechanical rationale for its use. This study aimed to determine whether restoring the constitutional alignment using a restrictive KA protocol resulted in better quantitative knee balance than mechanical alignment (MA). We conducted a randomized superiority trial comparing patients undergoing TKA assigned to KA within a restrictive safe zone or MA. Optimal knee balance was defined as an intercompartmental pressure difference (ICPD) of 15 psi or less using a pressure sensor. The primary endpoint was the mean intraoperative ICPD at 10° of flexion prior to knee balancing. Secondary outcomes included balance at 45° and 90°, requirements for balancing procedures, and presence of tibiofemoral lift-off.Aims
Methods
We report ten-year clinical and radiological
follow-up data for the Sigma Press Fit Condylar total knee replacement system
(Sigma PFC TKR). Between October 1998 and October 1999 a total of
235 consecutive PFC Sigma TKRs were carried out in 203 patients.
Patients were seen at a specialist nurse-led clinic seven to ten
days before admission and at six and 18 months, three, five and
eight to ten years after surgery. Data were recorded prospectively
at each clinic visit. Radiographs were obtained at the five- and
eight- to ten-year follow-up appointments. Of the 203 patients,
147 (171 knees) were alive at ten years and 12 were lost to follow-up.
A total of eight knees (3.4%) were revised, five for infection and
three to change the polyethylene insert. The survival at ten years
with an endpoint of revision for any reason was 95.9%, and with
an endpoint of revision for aseptic failure was 98.7%. The mean
American Knee Society Score (AKSS) was 79 (10 to 99) at eight to
ten years, compared with 31 (2 to 62) pre-operatively. Of 109 knee
with radiographs reviewed, 47 knees had radiolucent lines but none
showed evidence of loosening. Cite this article:
We report the ten-year survival of a cemented
total knee replacement (TKR) in patients aged <
55 years at the
time of surgery, and compare the functional outcome with that of
patients aged >
55 years. The data were collected prospectively
and analysed using Kaplan-Meier survival statistics, with revision
for any reason, or death, as the endpoint. A total of 203 patients
aged <
55 years were identified. Four had moved out of the area
and were excluded, leaving a total of 221 TKRs in 199 patients for
analysis (101 men and 98 women, mean age 50.6 years (28 to 55));
171 patients had osteoarthritis and 28 had inflammatory arthritis.
Four patients required revision and four died. The ten-year survival
using revision as the endpoint was 98.2% (95% confidence interval
94.6 to 99.4). Based on the Oxford knee scores at five and ten years,
the rate of dissatisfaction was 18% and 21%, respectively. This
was no worse in the patients aged <
55 years than in patients
aged >
55 years. These results demonstrate that the cemented PFC Sigma knee has
an excellent survival rate in patients aged <
55 ten years post-operatively,
with clinical outcomes similar to those of an older group. We conclude
that TKR should not be withheld from patients on the basis of age.
We have examined the differences in clinical outcome of total knee replacement (TKR) with and without patellar resurfacing in a prospective, randomised study of 181 osteoarthritic knees in 142 patients using the Profix total knee system which has a femoral component with features considered to be anatomical and a domed patellar implant. The procedures were carried out between February 1998 and November 2002. A total of 159 TKRs in 142 patients were available for review at a mean of four years (3 to 7). The patients and the clinical evaluator were blinded in this prospective study. Evaluation was undertaken annually by an independent observer using the knee pain scale and the Knee Society clinical rating system. Specific evaluation of anterior knee pain, stair-climbing and rising from a seated to a standing position was also undertaken. No benefit was shown of TKR with patellar resurfacing over that without resurfacing with respect to any of the measured outcomes. In 22 of 73 knees (30.1%) with and 18 of 86 knees (20.9%) without patellar resurfacing there was some degree of anterior knee pain (p = 0.183). No revisions related to the patellofemoral joint were performed in either group. Only one TKR in each group underwent a re-operation related to the patellofemoral joint. A significant association between knee flexion contracture and anterior knee pain was observed in those knees with patellar resurfacing (p = 0.006).
Compartment syndrome is a rare complication of total knee arthroplasty that requires early recognition and prompt decompression in order to prevent long-term disability. We have found only one previous case report in the literature. We present a series of seven cases from four hospitals and five surgeons. Six of the cases resulted in the loss of at least one compartment, and one resulted in amputation. Four of the cases resulted in legal action. We suggest that important risk factors contributing to the development of this condition include complex surgery, soft-tissue compromise, previous surgery, and possibly vascular disease. Delay in the diagnosis and hence delay in decompression was common in our series, and in five cases appeared to be related to the use of a postoperative epidural infusion for pain relief. The presence of associated neurological compromise may have also been a significant factor in the delay to diagnosis in two cases.
