Mismatch between trochlear coronal alignment of arthritic knees and currently available prosthesis: a morphological analysis of 4116 knees and 45 implant designs

Purpose: In up to a fifth of total knee replacements (TKR), surgeons are not capable of achieving good clinical and functional results. Despite comprehensive diagnostic workup, an underlying cause is not always identified in these patients. The purpose of this study is to compare native and prosthetic trochlear anatomies, to evaluate a potential source of morphologic mismatch and theoretically, of poor clinical outcomes. Methods: Native trochlear angles of 4116 knee CTs from 360 Knee Systems database of arthritic pre-operative TKR patients were evaluated. A semi-automated tridimensional analysis was performed to define the native trochlear angle in the coronal plane (NTA) among other 142 parameters. An active search was conducted to identify currently available TKR models; prosthetic trochlear orientation in the coronal plane (PTA) was extracted from the technical data provided by manufacturers. Results: The mean native trochlear angle (NTA) was 1.6° ± 6.6° (valgus) with a range from − 23.8° (varus) to 30.3°(valgus). A valgus NTA was present in 60.6% of the knees and 39.4% of them had a varus NTA. 89 TKR models were identified; trochlear details were available for 45 of them, of which 93% were designed with a valgus orientation of the prosthetic trochlear angle (PTA) and 6.9% showed a neutral (0°) PTA. Varus alignment of PTA was not present in any system. Angular numeric values for PTA were available for 34 models; these ranged from 0° to 15° of valgus, with a median value of 6.18° (SD ± 2.88°). Conclusion: This study shows a significant mismatch between native and prosthetic trochlear angles. A relevant proportion of the studied knees (41.45%) fall out of the trochlear angle range of currently available implants; representing a potential source for biomechanical imbalance. While further research is warranted to fully understand the clinical implications of the present study, manufacturers may need to take these findings into account for future implant designs. Level of evidence: Level III, retrospective cohort study

Computer-Aided Surgery-Navigated, Functional Alignment Total Knee Arthroplasty: A Surgical Technique

The decision on which technique to use to perform a total knee arthroplasty has become much more complicated over the last decade. The shortfalls of mechanical alignment and kinematic alignment has led to the development of a new alignment philosophy, functional alignment. Functional alignment uses preoperative radiographic measurements, computer-aided surgery, and intraoperative assessment of balance, to leave the patient with the most “normal” knee kinematics achievable with minimal soft-tissue release. The purpose of this surgical technique article is to describe in detail the particular technique needed to achieve these alignment objectives

Navigated functional alignment total knee arthroplasty achieves reliable, reproducible and accurate results with high patient satisfaction

Purpose: The decision on which technique to perform a total knee arthroplasty (TKA) has become more complicated over the last decade. Perceived limitations of mechanical alignment (MA) and kinematic alignment (KA) have led to the development of the functional alignment (FA) philosophy. This study aims to report the 2-year results of an initial patient cohort in terms of revision rate, PROMs and complications for Computer Aided Surgery (CAS) Navigated FA TKA. Methods: This paper reports a single surgeon’s outcomes of 165 consecutive CAS FA TKAs. The final follow-up was 24 months. Pre-operative and post-operative patient-reported outcome measures, WOMAC and KSS, and intra-operative CAS data, including alignment, kinematic curves, and gaps, are reported. Stress kinematic curves were analysed for correlation with CAS final alignment and CAS final alignment with radiographic long-leg alignment. Pre- and post-operative CPAK and knee phenotypes were recorded. Three different types of prostheses from two manufacturers were used, and outcomes were compared. Soft tissue releases, revision and complication data are also reported. Results: Mean pre-operative WOMAC was 48.8 and 1.2 at the time of the final follow-up. KSS was 48.8 and 93.7, respectively. Pre- and post-operative range of motion was 118.6° and 120.1°, respectively. Pre-operative and final kinematic curve prediction had an accuracy of 91.8%. CAS data pre-operative stress alignment and final alignment strongly correlate in extension and flexion, r = 0.926 and 0.856, p < 0.001. No statistical outcome difference was detected between the types of prostheses. 14.5% of patients required soft tissue release, with the lateral release (50%) and posterior capsule (29%) being the most common. Conclusion: CAS FA TKA in this cohort proved to be a predictable, reliable, and reproducible technique with acceptable short-term revision rates and high PROMs. FA can account for extremes in individual patient bony morphology and achieve desired gap and kinematic targets with soft tissue releases required in only 14.5% of patients. Level of evidence: IV (retrospective case series review)

Early Prosthetic Complications after Uncemented Austin Moore and Cemented Thompson Hemiarthroplasty. A Multicentre Review of 1118 Patients.

Introduction &amp; Aims For displaced intracapsular fractures of the femoral neck the most frequently employed hemiarthroplasty in Australia is the Uncemented Austin Moore (UAM) prosthesis. Despite concerns regarding the poor functional outcome and increased revision rates associated with the UAM prosthesis, apprehension about the systemic effects of PMMA acrylic cement implantation in the elderly patient continues to influence prosthesis selection. This study examines the incidence early prosthesis related complications after Uncemented Austin Moore (UAM) and Cemented Thompson (CT) hemiarthroplasty implantation for the management of femoral neck fractures

Surgical approach and early postoperative rehabilitation after computer assisted total knee arthroplasty

Computer Assisted Total Knee Arthroplasty (CA-TKA) has been demonstrated to provide more reproducible implant positioning compared to standard instrumentation, with potential benefits for prosthesis survival. When performing CA-TKA through a medial parapatellar (MPP) incision, proximal extension of the quadriceps dissection is frequently required for appropriate placement of the femoral tracking array. This study assesses early postoperative rehabilitation after CA-TKA using MPP and subvastus approaches.\ud Introduction\ud Computer Assisted Total Knee Arthroplasty (CA-TKA) has been demonstrated to provide more reproducible implant positioning compared to standard instrumentation, with potential benefits for prosthesis survival. When performing CA-TKA through a medial parapatellar (MPP) incision, proximal extension of the quadriceps dissection is frequently required for appropriate placement of the femoral tracking array. This study assesses early postoperative rehabilitation after CA-TKA using MPP and subvastus approaches.\ud Materials and Methods\ud Prospective randomized controlled trial of 70 consecutive patients undergoing TKA with the LCS Rotating Platform prosthesis. Outcome measures included preoperative knee function, intraoperative factors and postoperative rehabilitation.\ud Results\ud Duration of surgery was significantly longer when using computer navigation, however with greater experience operative times decreased. CA-TKA performed through the MPP approach was strongly associated with a greater incidence and duration of early postoperative quadriceps lag compared to CA-TKA through a subvastus approach and\ud TKA performed with standard instrumentation. No patient who had surgery performed through subvastus approach had a lag >20 degrees after 48 hours post surgery regardless of instrumentation system employed.\ud Discussion\ud This study demonstrates that CA-TKA is associated with delayed early postoperative rehabilitation when performed through the MPP approach. This observation is explained by the additional quadriceps dissection that is frequently required to place the femoral tracking array in CA-TKA. This data supports the use of a subvastus approach when performing CA-TKA due to a demonstrated quadriceps sparing effect

Closed Incision Negative Pressure Wound Therapy vs Conventional Dry Dressings After Primary Knee Arthroplasty: A Randomized Controlled Study

Background: The purpose of this study was to assess the effect of negative pressure wound therapy (NPWT) on quality of life (QoL), wound complications, and cost after primary knee arthroplasty. Methods: A prospective analysis of 33 patients undergoing primary knee arthroplasty performed by 3 surgeons in one institution. The first 12 patients (3 bilateral and 9 unilateral) had conventional dry dressings (CDD) applied and cost of dressings was assessed. The other 21 patients all underwent bilateral knee arthroplasty and had either side randomized to receiving NPWT or CDD. Cost of dressings, wound complications, and QoL were compared. Results: One patient had a reaction to the NPWT requiring readmission. Another had persistent wound drainage that required NPWT application. There were no wound issues in the remaining 31 patients. The average cost in the first 12 patients was Australian dollar $48.70 with an average of 1.5 changes on ward. In the 21 patients receiving both dressings, the average cost for CDD was less (Australian dollar$43.51 vs $396.02, P ≤ .011, effect size [ES] = 1.06). When comparing QoL factors, wound leakage (0.14 vs 0.39 P = .019, ES = 1.02), and wound protection (0.16 vs 0.33, P = .001, ES = 0.021) were better in the NPWT group. There was no other significant difference in QoL factors. The average number of changes on the ward was less for the NPWT group (1.19 vs 1.38, P = .317, ES = 1.02). Conclusion: We found no benefit in wound healing or cost with NPWT post knee arthroplasty. There was some benefit in NPWT QoL factors less wound leakage and better protection

Comparison of early postoperative rehabilitation outcome following total knee arthroplasty using different surgical approaches and instrumentation

Introduction\ud Computer Assisted Total Knee Arthroplasty (CA-TKA) has been demonstrated to provide more reproducible implant positioning compared to standard instrumentation, with potential benefits for prosthesis survival. When performing CA-TKA through a medial parapatellar (MPP) incision, proximal extension of the quadriceps dissection is frequently required for appropriate placement of the femoral tracking array. This study assesses early postoperative rehabilitation after CA-TKA using MPP and subvastus approaches.\ud \ud Materials and Methods\ud A prospective controlled trial of 70 consecutive patients undergoing TKA with the LCS Rotating Platform prosthesis was conducted with patients randomised to receive to surgery with the use of computer navigation or standard instrumentation. Medial parapatellar and subvastus approaches were employed according to surgeon preference. Outcome measures included preoperative knee function, intraoperative factors and postoperative rehabilitation. \ud \ud Results\ud Duration of surgery was significantly longer when using computer navigation, however with greater experience operative times decreased. CA-TKA performed through the MPP approach was strongly associated with a greater incidence and duration of early postoperative quadriceps lag compared to CA-TKA through a subvastus approach and TKA performed with standard instrumentation. No patient who had surgery performed through subvastus approach had a lag >20 degrees after 48 hours post surgery regardless of instrumentation system employed.\ud \ud Discussion\ud This study demonstrates that CA-TKA is associated with delayed early postoperative rehabilitation when performed through the MPP approach. This observation is explained by the additional quadriceps dissection that is frequently required to place the femoral tracking array in CA-TKA. This data supports the use of a subvastus approach when performing CA-TKA due to a demonstrated quadriceps sparing effect. \ud \ud KEY WORDS\ud \ud Knee. Arthroplasty. Approach. Computer. Rehabilitation

First observation and branching fraction measurement of the Λb0→Ds−p {\Lambda}_b^0\to {D}_s^{-}p decay

International audienceThe first observation of the ${\Lambda}_b^0\to {D}_s^{-}p$ decay is presented using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV, corresponding to a total integrated luminosity of 6 fb$^{−1}$. Using the ${\Lambda}_b^0\to {\Lambda}_c^{+}{\pi}^{-}$ decay as the normalisation mode, the branching fraction of the ${\Lambda}_b^0\to {D}_s^{-}p$ decay is measured to be $\mathcal{B}\left({\Lambda}_b^0\to {D}_s^{-}p\right)=\left(12.6\pm 0.5\pm 0.3\pm 1.2\right)\times {10}^{-6}$, where the first uncertainty is statistical, the second systematic and the third due to uncertainties in the branching fractions of the ${\Lambda}_b^0\to {\Lambda}_c^{+}{\pi}^{-}$, ${D}_s^{-}\to {K}^{-}{K}^{+}{\pi}^{-}$ and ${\Lambda}_c^{+}\to p{K}^{-}{\pi}^{+}$ decays.[graphic not available: see fulltext

Observation of the Bs0 ⁣→D∗+D∗−B^0_s\!\to D^{*+}D^{*-} decay

International audienceThe first observation of the ${B}_s^0$→ D$^{∗+}$D$^{∗−}$ decay and the measurement of its branching ratio relative to the B$^{0}$→ D$^{∗+}$D$^{∗−}$ decay are presented. The data sample used corresponds to an integrated luminosity of 9 fb$^{−1}$ of proton-proton collisions recorded by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV between 2011 and 2018. The decay is observed with more than 10 standard deviations and the time-integrated ratio of branching fractions is determined to be$\frac{\mathcal{B}\left({B}_s^0\to {D}^{\ast +}{D}^{\ast -}\right)}{\mathcal{B}\left({B}^0\to {D}^{\ast +}{D}^{\ast -}\right)}=0.269\pm 0.032\pm 0.011\pm 0.008,$where the first uncertainty is statistical, the second systematic and the third due to the uncertainty of the fragmentation fraction ratio f$_{s}$/f$_{d}$. The ${B}_s^0$→ D$^{*+}$D$^{*−}$ branching fraction is calculated to be$\mathcal{B}\left({B}_s^0\to {D}^{\ast +}{D}^{\ast -}\right)=\left(2.15\pm 0.26\pm 0.09\pm 0.06\pm 0.16\right)\times {10}^{-4},$where the fourth uncertainty is due to the B$^{0}$→ D$^{*+}$D$^{*−}$ branching fraction. These results are calculated using the average ${B}_s^0$ meson lifetime in simulation. Correction factors are reported for scenarios where either a purely heavy or a purely light ${B}_s^0$ eigenstate is considered.[graphic not available: see fulltext

Measurement of the CKM angle γγ with B±→D[K∓π±π±π∓]h± B^\pm \to D[K^\mp π^\pm π^\pm π^\mp] h^\pm decays using a binned phase-space approach

The CKM angle $\gamma$ is determined from $C\!P$-violating observables measured in ${B^\pm \to D[ K^\mp \pi^\pm\pi^\pm\pi^\mp] h^\pm}$, $(h = K,\pi)$ decays, where the measurements are performed in bins of the decay phase-space of the $D$ meson. Using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of $7, 8$ and $13\,\text{TeV}$, corresponding to a total integrated luminosity of $9\,\text{fb}^{-1}$, $\gamma$ is determined to be \begin{equation*} \gamma = \left( 54.8 \: ^{+\:6.0 }_{-\:5.8} \: ^{+\:0.6}_{-\:0.6} \: ^{+\:6.7}_{-\:4.3} \right)^\circ, \end{equation*} where the first uncertainty is statistical, the second systematic and the third from the external inputs on the coherence factors and strong phases of the $D$-meson decays.The CKM angle γ is determined from CP-violating observables measured in B$^{±}$ → D[K$^{∓}$π$^{±}$π$^{±}$π$^{∓}$]h$^{±}$, (h = K, π) decays, where the measurements are performed in bins of the decay phase-space of the D meson. Using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to a total integrated luminosity of 9 fb$^{−1}$, γ is determined to be$\gamma ={\left(54.8\begin{array}{c}+6.0\\ {}-5.8\end{array}\begin{array}{c}+0.6\\ {}-0.6\end{array}\begin{array}{c}+6.7\\ {}-4.3\end{array}\right)}^{\circ },$where the first uncertainty is statistical, the second systematic and the third from the external inputs on the coherence factors and strong phases of the D-meson decays.[graphic not available: see fulltext]The CKM angle $\gamma$ is determined from $C\!P$-violating observables measured in ${B^\pm \to D[ K^\mp \pi^\pm\pi^\pm\pi^\mp] h^\pm}$, $(h = K,\pi)$ decays, where the measurements are performed in bins of the decay phase-space of the $D$ meson. Using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of $7, 8$ and $13\,\text{TeV}$, corresponding to a total integrated luminosity of $9\,\text{fb}^{-1}$, $\gamma$ is determined to be \begin{equation*} \gamma = \left( 54.8 \: ^{+\:6.0 }_{-\:5.8} \: ^{+\:0.6}_{-\:0.6} \: ^{+\:6.7}_{-\:4.3} \right)^\circ, \end{equation*} where the first uncertainty is statistical, the second systematic and the third from the external inputs on the coherence factors and strong phases of the $D$-meson decays