Impact of increasing total knee replacement constraint within a single implant line on coronal stability: an ex vivo investigation.

INTRODUCTION: Despite the existence of diverse total knee implant designs, few data is available on the relationship between the level of implant constraint and the postoperative joint stability in the frontal plane and strain in the collateral ligaments. The current study aimed to document this relation in an ex vivo setting. MATERIALS AND METHODS: Six fresh-frozen lower limbs underwent imaging for preparation of specimen-specific surgical guides. Specimens were dissected and assessed for joint laxity using the varus-valgus stress tests at fixed knee flexion angles. A handheld dynamometer applied tensile loads at the ankle, thereby resulting in a knee abduction-adduction moment of 10 Nm. Tibiofemoral kinematics were calculated using an optical motion capture system, while extensometers attached to medial collateral (MCL) and lateral collateral ligament (LCL) measured strain. Native joint testing was followed by four TKA designs from a single implant line-cruciate retaining, posterior stabilised, varus-valgus constrained and hinged knee (HK)-and subsequent testing after each implantation. Repeated measures linear mixed-models (p < 0.05) were used to compare preoperative vs. postoperative data on frontal plane laxity and collateral ligament strain. RESULTS: Increasing implant constraint reduced frontal plane laxity across knee flexion, especially in deep flexion (r2 > 0.76), and MCL strain in extension; however, LCL strain reduction was not consistent. Frontal plane laxity increased with knee flexion angle, but similar trends were inconclusive for ligament strain. HK reduced joint laxity and ligament strain as compared to the native condition consistently across knee flexion angle, with significant reductions in flexion (p < 0.024) and extension (p < 0.001), respectively, thereby elucidating the implant design-induced joint stability. Ligament strain exhibited a strong positive correlation with varus-valgus alignment (r2 = 0.96), notwithstanding knee flexion angle or TKA implant design. CONCLUSION: The study demonstrated that increasing the constraint of a TKA resulted in lower frontal plane laxity of the knee. With implant features impacting laxity in the coronal plane, consequentially affecting strain in collateral ligaments, surgeons must consider these factors when deciding a TKA implant, especially for primary TKA. LEVEL OF EVIDENCE: V.

Prevalence, interpretation, and management of unexpected positive cultures in revision TKA: a systematic review.

PURPOSE: Unexpected positive intraoperative cultures (UPIC) found in revision total knee arthroplasty (TKA) are difficult to interpret. Management goes along with risks for both over- and undertreating a potential periprosthetic joint infection (PJI). The objective of this systematic review was to determine the prevalence of UPIC in revision TKA surgery, evaluate the diagnostic workup process and the postoperative treatment, and assess outcome regarding re-revision rates. METHODS: Evidence was gathered from Medline (PubMed) and Embase published from January 2000 until April 2021. Nine studies with data of UPIC in revision TKA and outcome after at least 2 years of follow-up were identified. RESULTS: The calculated prevalence of UPIC in aseptic knee revision surgery was 8.32%. However, the diagnostical approach differs as well as the used criteria to confirm PJI in presumed aseptic revision surgery. The work-up generally consists of a serum C-reactive protein and Erythrocyte Sedimentation Rate, joint fluid aspiration for culture and white blood cell count and formula, and radiographic imaging. Collection of intraoperative cultures is widely used, but inconsistent in sample amount and incubation time. Once a single UPIC is found, surgeons tend to treat it in different ways. Regarding re-revision rates, the weighted arithmetic mean in the included studies was 18.45% in the unsuspected PJI group compared to 2.94% in the aseptic group. There also seems to be a trend towards higher re-revision rates when a higher number of intraoperative cultures are positive. CONCLUSION: The interpretation of UPIC in revision TKA is of utmost importance since the decision whether to treat a UPIC as an unsuspected PJI has a major impact on implant survival and re-revision rate. Different criteria are used to differentiate between unsuspected PJI and contamination in true aseptic failure, and the heterogeneity amongst the included papers impedes to state a clear recommendation, integrating not only quantitative findings, but also qualitative data such as virulence of the identified microorganism. LEVEL OF EVIDENCE: Systematic review, III.

Good long-term survival and patient-reported outcomes after high tibial osteotomy for medial compartment osteoarthritis.

The lateral closing and medial opening wedge high tibial osteotomy can correct a varus malalignment of the knee caused by medial compartment osteoarthritis. These procedures have produced great short-term and mid-term results. As no systematic review has examined their long-term results yet, the goal of this article was to compare the results of all articles about lateral closing and medial opening wedge high tibial osteotomies, published after the year 2000, with a mean follow-up of more than 10 years. A systematic search of the Medline, Web of Science and Cochrane databases resulted in the inclusion of 30 articles. All these studies combined examined the results of 7087 high tibial osteotomies in a total of 6636 patients after a mean follow-up of more than 10 years. Primary outcome measures were the survival rate of the osteotomy, functional scores, patient satisfaction and pain scores. Secondary outcome measures were alignment correction and the identification of factors influencing the survival of the osteotomy. The 5-year, 10-year, 15-year and 20-year survival rates, respectively, ranged from 86 to 100%, 64-97.6%, 44-93.2% and 46-85.1%. The subjective scoring systems showed an improvement postoperatively that was maintained until final follow-up. The anatomical and mechanical tibiofemoral axis were, respectively, corrected to a mean of 7.3°-13.8° of valgus and 0.6°-4° of valgus. The results of the articles evaluating the influence of potential risk factors were contradictory. Despite the low quality of the available evidence, the lateral closing and medial opening wedge high tibial osteotomy seem to remain valid long-term treatment options for patients with painful varus malalignment caused by isolated medial compartment osteoarthritis of the knee. The available results indicate that the need for arthroplasty could be delayed for more than 15 years in the majority of patients. However, higher-quality studies are needed to confirm these findings. As a systematic review is assigned a level of evidence equivalent to the lowest level of evidence used from the analyzed manuscripts, the level of evidence of this systematic review is IV.

Can Intraoperative Intra-Articular Loads Predict Postoperative Knee Joint Laxity Following Total Knee Arthroplasty? A Cadaver Study with Smart Tibial Trays.

Ligament balancing during total knee arthroplasty (TKA) often relies on subjective surgeon experience. Although instrumented tibial trays facilitate an objective assessment of intraoperative joint balance through quantification of intra-articular joint loads, postoperative clinical assessment of joint balance relies on passive stress tests quantifying varus-valgus joint laxity. This study aimed at correlating the intraoperative and postoperative metrics used to assess joint balance while also comparing joint loads obtained during passive assessment and active functional motions. Four experienced surgical fellows were assigned a fresh-frozen lower limb each to plan and perform posterior-stabilised TKA. An instrumented tibial insert measured intraoperative intra-articular loads. Specimens were then subjected to passive flexion-extension, open-chain extension, active squatting, and varus-valgus laxity tests on a validated knee simulator. Intra-articular loads were recorded using the instrumented insert and tibiofemoral kinematics using an optical motion capture system. A negative correlation was observed between mean intraoperative intra-articular loads and corresponding mean postoperative tibial abduction angle during laxity tests (medial: R = -0.93, p = 0.02; lateral: R = -0.88, p = 0.04); however, this was not observed for each specimen. Peak intra-articular load distribution for active squatting was lateral-heavy, contrasting to the medial-heavy distribution observed in passive intraoperative measurements, for all specimens. These aspects should be given due consideration while assessing intraoperative and postoperative joint stability following TKA.

Bicruciate retaining total knee arthroplasty : results throughout history.

Approximately 20% amongst patients are dissatisfied after total knee arthroplasty (TKA). Bicruciate retaining (BCR) TKA offers superior knee kinematics and proprioception, but many surgeons abandoned its use because of complications and technical difficulties. Recently, two new BCR implant designs were introduced : Vanguard XP (Zimmer Biomet) and Journey XR (Smith&Nephew). We searched Pubmed, Limo, Embase and Cochrane, screened reference lists of eligible studies and included studies that met the inclusion criteria. We included 35 articles reporting on ten different BCR implants, including three articles presenting results of the Vanguard XP prosthesis. Unfortunately, no articles reporting on the results of the Journey XR prosthesis had been published. The BCR implants of the early 1970s showed good functional results, but a high rate of complications, mainly loosening and infections. The Townley Anatomic TKA was the first BCR implant with good clinical results, a low incidence of loosening and a high survivorship. One article of the three reporting on the Vanguard XP yielded high patient satisfaction (94%) with two revisions (1.4%). The two other articles reported three revisions (5%) after one year of follow-up and 19 revisions (13.4%) after three years of follow-up. Throughout history, the functional results of BCR TKA improved, with lessening of the complications. The short-term results of the Vanguard XP implant showed good functional results, but two out of three articles reported a high rate of loosening. Based on the results reported in this review, the use of BCR TKA is still debatable. Further high-level evidence research is necessary to assess the clinical benefit of BCR TKA.

Metal wear debris generation in primary total knee arthroplasty: is it an issue?

More durable total knee arthroplasties (TKAs) are needed, due to the rising life expectancy, the higher activity levels of patients and the growing concerns about aseptic loosening being caused by metal hypersensitivity. In response, different hypoallergenic metal coatings have been developed for TKAs. However, possible adverse effects of these different metals (cobalt-chromium-molybdenum, zirconium, titanium and tantalum) have been neglected. The aim was to summarize the local and systemic adverse effects (including metal hypersensitivity), survival ratios, patient-reported outcome measures (PROMs) and the plasma metal ion concentrations of the different TKA coatings. A literature search on PubMed and EMBASE was performed. In total, 15 studies were found eligible. Common adverse effects of TKA were infection, loosening, pain, instability and hyper- coagulation disorders. Serious adverse effects related to TKA implants were not reported. The survival ratios and patient-reported outcome measures seem to confirm these good results. In contrast with chromium and cobalt, no significant differences were reported in the nickel, molybdenum and titanium concentrations. No significant differences between the hypoallergenic and standard TKA implants were found in terms of adverse effects, survival ratios and PROMs. A causal relationship between the common adverse effects and the different metals is unlikely. Due to the heterogeneity of the TKA implants used, no firm conclusions could be made. Further research with longer follow-up studies are needed to find possible adverse effects and differences. Thus far, the hypoallergenic implants seem to perform equal to the standard implants.

Mucoid degeneration of the anterior cruciate ligament. Complete resection as equivalent treatment to partial resection.

Mucoid degeneration (MD) of the anterior cruciate ligament (ACL) is a benign knee pathology, which is often indicated for surgical treatment if symptomatic. Most authors believe that partial ACL resection is the treatment of choice in symptomatic MD of the ACL. This study concerns complete ACL resection as a treatment of mucoid degenerated ACL. Thirteen patients were treated with complete ACL resection for symptomatic MD of the ACL from 2006-2016. Symptoms included limited range of motion (ROM) and posterior knee pain. Preoperative and postoperative results of eleven patient were compared. Postoperative recovery was four weeks on average. All patients (100%, n=11) reported an improvement in pain. All patients with a preoperative limited ROM (100%, n=9) reported a return to a normal (subjective) ROM. Eight patients (72.7%, n=8) reported an improvement of knee instability, while three patients (27.3%, n=3) experienced an unchanged knee stability. All patients (100%, n=11) reported a good to very good surgery satisfaction. Preoperative and postoperative KOOS questionnaires were compared and showed improvement in all categories. Complete resection of the ACL without ACL reconstruction is a reliable treatment for symptomatic cases of mucoid degenerated ACL.

What are the determinants for return to work after primary total knee arthroplasty?

Total knee arthroplasty is increasingly performed on patients of working age, although little is known about return to work. This study aims to analyse the return to work percentage in a Belgian population and to identify underlying determinants. Data was gathered by analysing patients' files and sending a questionnaire to patients aged ≤ 62 years who underwent a total knee arthroplasty between January 2013 and December 2017 in the University Hospitals of Leuven. A total of 99 patients were included in the study and 66 patients returned to work. Significant factors included preoperative sick leave, availability of job adaptations, employment type and postoperative Knee Society Score. The return to work percentage of 67% in this Belgian population is slightly lower in comparison with similar studies in other countries. This difference could be driven by Belgium's specific insurance system or due to a lack of clear prescription guidelines for medical doctors.

Flexor Pollicis Longus Tendon Rupture After Volar Wrist Plating : Reconstruction With Palmaris Longus Interposition Graft.

Rupture of the flexor pollicis longus tendon is a rare complication after volar plating of distal radius fractures. Several surgical treatment options have been proposed but postoperative results are not well documented. The authors retrospectively studied the clinical outcome of 4 patients after flexor pollicis longus tendon reconstruction with a palmaris longus interposition graft. Minimal follow-up was 12 months. Mean active interphalangeal joint flexion (44°) and thumb opposition (Kapandji 8/10) were significantly reduced compared to the opposite side. Mean power grip (32 kg) and key pinch strength (8kg) of the operated hand were comparable to the contralateral hand. The mean Visual Analogue Scale for pain was 2.5/10. The mean DASH score was 14 points. Although flexion and opposition of the thumb did not return to normal after surgery, patients reported excellent functional results.

Comparison of immediate versus optional delayed surgical repair for treatment of acute anterior cruciate ligament injury through a parallel, multicentric, pragmatic randomized controlled trial - IODA trial.

BACKGROUND: Standard care for anterior cruciate ligament (ACL) injuries often includes surgical reconstruction of the ACL. However, two randomized controlled trials [1, 2] (RCT) concluded that conservative treatment does not result in inferior clinical outcomes compared to immediate ACL reconstruction. More research is needed to verify these results and assess whether patient-specific parameters determine if a patient would benefit from one treatment option over the other. METHODS: This is a pragmatic, multi-center RCT with two parallel groups. Patients with an acute ACL injury will be recruited from Belgian hospitals. Patients will be randomized to conservative treatment (rehabilitation + optional delayed surgery) or immediate ACL reconstruction (< 12 weeks). The primary outcome is the Knee injury and Osteoarthritis Outcome Score (KOOS) at 7 months (short term) and 1-year long term) post-injury. These following additional outcomes will be administered at 4 and 7 months (short term) and 1, 2, and 3 years post-injury (long term): patient-reported outcomes concerning knee symptoms, knee function and quality of life, functional knee tests, time to return to pre-injury activity level and return to work, structural knee joint damage and cartilage health (only at 4 months and 3 years post-injury), as well as adverse events such as re-rupture rates. Furthermore, the secondary objective is to identify (through a predictive analysis) individuals who would benefit the most from early reconstruction versus those who should rather be treated conservatively. DISCUSSION: This large RCT will assess the clinical effectiveness of both surgical and conservative treatment. In addition, it will be the first study that provides insights into which patient-specific factors predict successful outcomes after conservative treatment of ACL injuries. These results will be the first step toward early patient identification regarding treatment decisions. This is urgently needed to avoid (1) delayed surgeries and prolonged rehabilitation and (2) unnecessary surgeries. TRIAL REGISTRATION: this trial was registered on ClinicalTrials.gov (NCT05747079) on 10/02/2023.

A Simple Technique for Reconstruction of the Medial Patellofemoral Ligament With Patellar Soft-Tissue Fixation Using Synthetic Suture Tape Internal Bracing.

Recurrent patellar dislocation is most commonly treated with an isolated medial patellofemoral ligament reconstruction using autograft tissue. Harvest and fixation of these grafts have some theoretical disadvantages. With this Technical Note, we aim to describe a simple reconstruction of the medial patellofemoral ligament using high-strength suture tape with a soft-tissue fixation on the patellar side and an interference screw fixation on the femoral side, avoiding some of these possible disadvantages.

Return to Work after Primary Total Knee Arthroplasty under the Age of 65 Years: A Systematic Review.

A growing number of patients undergoing total knee arthroplasty (TKA) is at working age and need to return to work (RTW) after surgery. The aim of this systematic review is to give an overview of the literature regarding RTW after TKA and beneficial and limiting factors influencing this process. A systematic search in four electronic databases was conducted in November 2019 to identify studies describing RTW after primary TKA in patients aged 65 years or younger. Study characteristics and data on work status before and after surgery were extracted. All studies were assessed for risk of bias. Fourteen studies published between 2009 and 2019 were included in this review, accounting for a total of 3,073 patients. The percentage of patients working after TKA ranged from 36 to 89%, and the fraction of patients working before and returning to work after surgery ranged from 40 to 98%. Mean time of RTW ranged from 7.7 to 16.6 weeks. Most important factors associated with a slower or no RTW were a more physical nature of employment and preoperative absence from work. The majority of patients undergoing TKA returned to work postoperatively. However, comparison between studies is seriously hampered by the wide variation regarding the definition and timeframe used to measure the work status. Therefore, standardized outcome measures for studies investigating RTW after TKA are warranted. We identify this review as level-I evidence (systematic review of level-I and level-II studies).

Assessment of in vivo bone activity patterns in medial mobile-bearing unicompartmental knee arthroplasty : a prospective SPECT/CT study.

AIMS: Higher osteoblastic bone activity is expected in aseptic loosening and painful unicompartmental knee arthroplasty (UKA). However, insights into normal bone activity patterns after medial UKAs are lacking. The aim of this study was to identify the evolution in bone activity pattern in well-functioning medial mobile-bearing UKAs. METHODS: In total, 34 patients (13 female, 21 male; mean age 62 years (41 to 79); BMI 29.7 kg/m2 (23.6 to 42.1)) with 38 medial Oxford partial UKAs (20 left, 18 right; 19 cementless, 14 cemented, and five hybrid) were prospectively followed with sequential 99mTc-hydroxymethane diphosphonate single photon emission CT (SPECT)/CT preoperatively, and at one and two years postoperatively. Changes in mean osteoblastic activity were investigated using a tracer localization scheme with volumes of interest (VOIs), reported by normalized mean tracer values. A SPECT/CT registration platform additionally explored cortical tracer evolution in zones of interest identified by previous experimental research. RESULTS: Significant reduction of tracer activity from the preoperative situation was found in femoral and anteromedial tibial VOIs adjacent to the UKA components. Temporarily increased osteoblastic bone activity was observed in VOIs comprising the UKA keel structure at one year postoperatively compared to the preoperative activity. Persistent higher tracer uptake was found in the posterior tibial cortex at final follow-up. Multivariate analysis showed no statistical difference in osteoblastic bone activity underneath cemented or cementless components. CONCLUSION: Well-functioning medial mobile-bearing UKAs showed distinct changes in patterns of normalized bone tracer activity in the different VOIs adjacent to the prosthetic components, regardless of their type of fixation. Compared to the preoperative situation, persistent high bone activity was found underneath the keel and the posterior tibial cortex at final follow-up, with significant reduced activity only being identified in femoral and anteromedial tibial VOIs. Cite this article: Bone Joint J 2022;104-B(1):34-44.

Pilot study to investigate the feasibility of conducting a randomised controlled trial that compares Immediate versus Optional Delayed surgical repair for treatment of acute Anterior cruciate ligament injury: IODA pilot trial.

INTRODUCTION: Standard care for anterior cruciate ligament (ACL) injuries includes surgical reconstruction of the ACL. However, two randomised controlled trials (RCTs) concluded that conservative treatment does not result in inferior clinical outcomes compared with immediate ACL reconstruction. More research is needed to in the first place verify these results, and second to assess whether patient-specific parameters determine whether a patient would benefit from one treatment option over the other. However, before running a full RCT, it seems necessary to perform a pilot study that assesses the feasibility of recruiting patients with ACL for such a RCT. This is because recruitment may be challenging as many patients have strong treatment beliefs. Therefore, this pilot study will assess whether a large RCT is feasible with regard to participant recruitment, adherence to the allocated treatment arm and protocol feasibility. These pilot findings will help deciding about progressing to a future full RCT. METHODS AND ANALYSIS: This is a pragmatic, multicentre, randomised controlled pilot trial with two parallel groups. Patients with an acute ACL injury will be recruited from two Belgian hospitals. Patients will be randomised to either conservative treatment or surgical treatment. Patients will be followed-up at 3, 6 and 12 months postrandomisation. Recruitment feasibility will be evaluated by calculating the recruitment rate 4 months after the two sites have been initiated. Clear criteria for progression to a full trial are defined. Adherence to the protocol will be assessed by calculating the proportion of patients who complete the assessments. Furthermore the proportion of patients who cross-over between treatment arms during the follow-up period will be assessed. ETHICS AND DISSEMINATION: The study was approved by the ethical committees: Ethische Commissie Onderzoek UZ/KU Leuven (S62004) and Comité d'Ethique Hospitalo-Facultaire Universitaire de Liège (2020212). Results will be made available to caregivers, researchers and funder. TRIAL REGISTRATION NUMBER: This trial is registered on ClinicalTrials.gov (NCT04408690) on 29 May 2020.

Total hip arthroplasty in patients less than 40 years old with avascular necrosis of the femoral head. A 5 to 19-year follow-up study.

We evaluated 34 total hip arthroplasties (THA) for avascular necrosis of the femoral head in 26 patients who were younger than 40 years at the time of the index operation. The average age at the time of THA was 283 (17-38) years. The mean follow-up was 10.9 (5-19) years. We used 6 cemented and 28 cementless acetabular components and a cemented polished tapered stem in all hips. The mean Charnley modified Merle d' Aubigné Postel score was 8.9 points preoperatively and 16.6 points at final follow-up. Two cemented metal-backed cups were revised because of aseptic loosening at 10 years, one cemented polyethylene cup failed at 12 years and 2 more all polyethylene cups had pending failure. The metal-backed cemented cups and the all polyethylene cups had a longer follow-up than the uncemented cups. Therefore and because of the proven unfavourable long-term outcome of the cemented metal-backed Exeter cup we are not able to draw any firm conclusions regarding the preferred choice between cemented and uncemented cups in this particular group of patients. On the femoral site none of the stems had to be revised. Our results show that a cemented polished tapered femoral component has an excellent survival in primary total hip replacement in young patients with avascular necrosis of the femoral head.

Ilizarov bone transport as a treatment of congenital pseudarthrosis of the tibia: a long-term follow-up study.

PURPOSE: Most studies on congenital pseudarthrosis of the tibia (CPT) report on the short-term union rate and refracture rate but do not take into account the long-term outcome. This review includes patients treated with an Ilizarov bone transport, who all reached skeletal maturity. It describes long-term results and highlights any prognostic factors that could predict the final outcome. METHODS: The records of patients with CPT treated with an Ilizarov bone transport in our institution were retrospectively evaluated. RESULTS: A total of 12 consecutive patients were studied. The mean follow-up was 24.5 years (range 6-39 years). Primary consolidation was seen in ten patients (83 %). Half of these patients had a refracture. At final follow-up, eight patients experienced union and four remained un-united, of whom one had an amputation. CONCLUSIONS: The present data confirm a good primary healing rate. However, tibial union at final follow-up was only seen in 67 %, indicating that refracture is the main issue. United bone is often of inferior biological and mechanical quality, so lifetime protection with intramedullary devices, braces or a combination of both is recommended.