Introduction: High tibial osteotomy is considered as alternative treatment for the unicompartmental arthritis of the varus knee. Low tibial osteotomy due to delayed union is avoided. Corticotomy and the use of external fixation system for stabilization and progressive correction of the axis offers all the osteotomie’s advantages, and, furthermore, reduces the bone healing time. Material and Method: Fifty-seven patients, aged 49–76 y. (mean age 63.2 y.) with unicompartmental arthritis of the knee were treated, using the above technique. In all the cases arthroscopy was firstly performed to examine the knee joint. The mean time of external fixation presevation was six weeks. Folllow-up examination ranged from 6 months to ten years (mean time 6 y.). Since, the second postoperative day partial weight bearing was permitted. Patient’s hospitalization was 3 days. Postoperative correction of the axis was 1° per day, for 12–15 days. Results: Regarding the pain and the range of motion the results are excellent in 49/57 patients. Loss of full knee extension was presented in one patient. Lateral knee instability and pain were presented in 3 patients. One patient was submitted in total knee arthroplasty two years after the osteotomy. Delayed-union of the osteotomy was presented in 4 patients that were fully healed, while non-union was presented in one patient. Two patients presented peroneal nerve neurapraxia, that were fully healed. Conclusion: Conclusively, knee osteotomy with the use of external fixation system and progressive correction of the axis is a reliable method for the treatment of the unicompartmental arthritis of the knee. It permits the early weight bearing of the limb and offers very good results regarding pain and range of motion

The accurate assessment of compartmental involvement in degenerative arthritis of the knee is important when planning operative treatment. Standard radiographic techniques often fail to define the degree of involvement of the less affected tibiofemoral compartment. The use of stress radiography in the preoperative assessment of 30 knees with degenerative arthritis is described and the radiographic findings correlated with the changes found at arthrotomy

1. High tibial osteotomy-above the tibial tubercle-gives good results in elderly patients disabled by arthritis of the knee. 2. A technique of operation is described in which fixation is secured by four pins gripped in compression clamps. 3. No other fixation is needed, and knee movements and walking are encouraged within a few days of operation. 4. The early results warrant further trial of the method

Background: Osteoarthritis (OA) is a common phenomena in the population. About 80% of the patients more than 55 years of age have reontgenographic signs of OA, while 25% have clinical signs. Eventually OA leads to joint destruction, which may necessitate joint replacement. Aims: Our goal was to evaluate the synovial reaction in 10 patients who suffered from arthritis and thus underwent total knee replacement operation. Methods: Ten patients with arthritis of the knee joint (8 with OA and 2 with rheumatoid arthritis (RA) who underwent total knee replacement were evaluated. Age ranged between 66 and 79 years (mean 71 years). A control group consisted of 6 cadaver knees (mean age 31 years) with no previous history of knee problems. All the patients in the research group were graded functionally for their knee score by the system of Hospital for Special Surgery Functional Score. Additional plain X-ray score on a three point scale was performed. During surgery macroscopic changes on the articular surface of all three compartments were recorded on a four point scale. Synovial specimens were taken from each compartment for microscopic examination. Results: In the research group the average knee score was 54. The macroscopic changes were found predominantly in the medial compartment. No correlation was found between microscopic and histological changes in the synovia. However, a statistically significant correlation between radiological changes in the medial and lateral compartments and macroscopic changes was noted. In the OA patients the ratio of T to B cells was 60% in favor of the B cells, in contrast to RA which was 75% in favor of T cells. In the control group the common find-ing was a thickened sub-synovial fat layer in the patello-femoral (PF) compartment. Conclusions: Inflammatory reaction in the synovia is graded by the lymphocytic infiltration into the synovia. In OA this is usually mild. However, the predominant reaction is fibrosis. There is no correlation between this fibrotic reaction and overt radiological or macroscopic findings. The thick subsynovial fat layer found in the PF compartment in the control group has not been described previously in the literature and should be the focus of further investigations

Introduction. The authors performed a short term prospective study of unicompartmental knee replacement (UKR) associated to patella-femoral arthroplasty (PFA) for the treatment of bicompartmental symptomatic knee arthritis. At the latest follow-up all the implants were matched to a similar computer assisted Total Knee Replacements (CAS-TKR) group implanted for the same indications. Hypothesis of the study was that this bicompartimental implants could achieve comparable outcomes to TKR with a more conservative surgery and a higher joint function. Materials and Methods. 19 cases of anteriomedial (12) or anterolateral (7) arthritis in 19 stable knees were prospectively involved in the study. All the knees underwent to a selective reconstruction using simultaneously both UKR and PFR using the same surgical technique. All bicompartmental implants were performed by the same surgeon. Surgical time, hospital staying and all intra and post operative complications were registered. At a minimum follow-up of 20 months, every single case was marched to a similar case where had been implanted a computer assisted cruciate retaining TKR. Criteria of matching were: sex, age, pre-operative range of motion and arthritis grade. In both the groups all the cases were assessed clinically using WOMAC, KKS and GIUM scores. All the knees were radiologically investigated using the same radiological protocol. Results. Intra operatively we did not registered any complication. No revision in both groups. The mean surgical time was 86 minutes (range: 78–121) in UKR+PFR group and 81 minutes (range: 71–112) in CAS-TKR group. There were no statistical significant differences in the hospital stay. No statistically significant difference was seen for the Knee Society, Functional and GIUM scores between the 2 groups. Statistically significant better WOMAC Function/Stiffness indexes were registered for the UKR+PFR group. CAS-TKR implants achieved a statistically better aligned mechanical axes. Conclusions. The results of this prospective short term prospective study suggest that UKR+PFR implant is a viable option for bicompartmental anteromedial arthritis at least as well as TKR but maintaining an higher level of function

The aim of this study was to assess the effect of injecting genetically engineered chondrocytes expressing transforming growth factor beta 1 (TGF-β1) into the knees of patients with osteoarthritis. We assessed the resultant function, pain and quality of life.

A total of 54 patients (20 men, 34 women) who had a mean age of 58 years (50 to 66) were blinded and randomised (1:1) to receive a single injection of the active treatment or a placebo. We assessed post-treatment function, pain severity, physical function, quality of life and the incidence of treatment-associated adverse events. Patients were followed at four, 12 and 24 weeks after injection.

At final follow-up the treatment group had a significantly greater improvement in the mean International Knee Documentation Committee score than the placebo group (16 points; -18 to 49, vs 8 points; -4 to 37, respectively; p = 0.03). The treatment group also had a significantly improved mean visual analogue score at final follow-up (-25; -85 to 34, vs -11 points; -51 to 25, respectively; p = 0.032). Both cohorts showed an improvement in Western Ontario and McMaster Osteoarthritis Index and Knee Injury and Osteoarthritis Outcome Scores, but these differences were not statistically significant. One patient had an anaphylactic reaction to the preservation medium, but recovered within 24 hours. All other adverse events were localised and resolved without further action.

This technique may result in improved clinical outcomes, with the aim of slowing the degenerative process, leading to improvements in pain and function. However, imaging and direct observational studies are needed to verify cartilage regeneration. Nevertheless, this study provided a sufficient basis to proceed to further clinical testing.

Cite this article: Bone Joint J 2015;97-B:924–32.

One hundred and forty eight meniscus allografts transplanted in one hundred and forty patients between 1988 and 2000 were reviewed. The indication for surgery included disabling knee pain, refractory to conservative treatment, objective symptoms of compartmental crepitus, pain on valgus/varus stress and osteoarthritis documented on arthroscopy following prior total meniscectomy. Knee mal-alignment and instability were also documented. Patients with varus alignment and medial OA, as well as valgus alignment with lateral OA, underwent re-alignment to unload the compartment for allograft transplantation. Patients with anterior cruciate deficiency, underwent ACL reconstruction at the time of allograft transplantation.

The purpose of this paper is to show the benefit of meniscus transplantation in osteoarthritis of the knee.

At a mean follow-up of six years (range two to fourteen), one hundred and twenty-five out of one hundred and forty-eight knees received good to excellent results.

Meniscus allograft transplantation can restore function in patients with arthritis secondary to prior total meniscectomy. The transplantation of a biological load-bearing structure has given reliable long term results, when used in well selected cases.

Forty six patients received an isolated meniscus allograft with forty-one receiving good to excellent results. Eleven received a medial or lateral meniscus allograft with an ACL reconstruction and nine obtained good to excellent results. Seventy five knees received a meniscal allograft in combination with an osteotomy to correct for pre-operative deformity, with sixty-four attaining good to excellent results. The remaining twenty-two knees underwent valgus high tibial osteotomy, meniscus allograft and ACL repair, with nineteen achieving good to excellent results.

Outcome was assessed subjectively and functionally using a modified Lysholm socre and objectively by clinical examination. The Tegner activity scale was used to compare pre and post- operative function. Second look arthroscopy was performed on the first ten transplanted meniscus to assess healing and graft integrity.

We describe a case of septic arthritis of the knee in which the diagnosis of tuberculosis was masked by an initial culture growth of Staphylococcus aureus. This led to a delay in diagnosis and an adverse outcome. In the appropriate clinical setting, we suggest that the index of suspicion for skeletal tuberculosis be raised in developed countries in order to avoid diagnostic delay, by requesting cultures for acid-fast bacilli and synovial biopsies at arthroscopy. Moreover, antituberculosis therapy should be started whilst awaiting the results of culture if the clinical history and biopsies are strongly suggestive of the diagnosis.

Introduction: Meniscus allograft transplantation can restore function in patients with arthritis secondary to prior total meniscectomy. The transplantation of a biological load-bearing structure in young patients has given reliable long-term results, when used in well-selected cases.

Method: One hundred and forty-eight meniscus allografts transplanted in l40 patients between 1988 and 2000 were reviewed. The indication for surgery included disabling knee pain, refractory to conservative treatment, objective symptoms of compartmental crepitus, pain on valgus/varus stress and osteoarthritis documented on arthroscopy following prior total meniscectomy. Knee mal-alignment and instability were also documented. Patients with varus alignment and medial OA, as well as valgus alignment with lateral OA, underwent re-alignment to unload the compartment for allograft transplantation. Patients with anterior cruciate deficiency, underwent ACL reconstruction at the time of allograft transplantation.

Results: At a mean follow-up of six years (range two to 14). One hundred and twenty-five received a good to excellent result. Forty-six patients received an isolated meniscus allograft, with 41 receiving good to excellent results. Eleven received a medial or lateral meniscus allograft with an ACL reconstruction and nine obtained good to excellent results. Seventy-five knees received a meniscal allograft in combination with either a valgus high tibial osteotomy, varus high tibial osteotomy or varus distal femoral osteotomy to correct for pre-operative deformity with l26 attaining good to excellent results. The remaining 22 knees underwent valgus high tibial osteotomy, meniscal allograft and ACL repair with 19 receiving good to excellent results.

Outcome was assessed subjectively and functionally using a modified Lysholm score and objectively by clinical examination of stress pain and joint crepitus. The Tegner activity scale comparing pre- and post-operative function was applied. Second-look arthroscopy was performed on the first l0 transplanted meniscii to assess healing and integrity of the transplantation graft.

The most frequent complication was a traumatic posterior horn tear in l3 knees.

1. The technique of the intra-articular surgery employed by the late Mr K. H. Pridie for osteoarthritis of the knee is described.

2. The results of sixty-two operations in sixty patients are analysed. The results in forty-eight knees (77 per cent) were pleasing to the patient. Forty knees (64 per cent) were rated as good at review.

3. The operation is most suitable for relatively active healthy people whose disability warrants a comparatively painful operation and lengthy rehabilitation.

4. The operation was most successful for relieving pain and improving stability. Functional improvement was less.

5. Results were remarkably permanent. The knees showed little tendency towards further deterioration.

6. Most of the bad results were associated with removal of the patella. A possible technical reason for this has been discussed.

A prospective, randomised, controlled trial compared two different techniques of high tibial osteotomy with a lateral closing wedge or a medial opening wedge, stabilised by a Puddu plate. The clinical outcome and radiological results were examined at one year.

The primary outcome measure was the achievement of an overcorrection of valgus of 4°. Secondary outcome measures were the severity of pain (visual analogue scale), knee function (Hospital for Special Surgery score), and walking distance.

Between January 2001 and April 2004, 92 patients were randomised to one or other of the techniques. At follow-up at one year the post-operative hip-knee-ankle angle was 3.4° (± 3.6° sd) valgus after a closing wedge and 1.3° (± 4.7° sd) of valgus after an opening wedge. The adjusted mean difference of 2.1° was significant (p = 0.02). The deviation from 4° of valgus alignment was 2.7° (± 2.4° sd) in the closing wedge and 4.0° (± 3.6° sd) in the opening-wedge groups. The adjusted mean difference of 1.67° was also significant (p = 0.01).

The severity of pain, knee score and walking ability improved in both groups, but the difference was not significant.

Because of pain, the staples required removal in 11 (23%) patients in the closing-wedge group and a Puddu plate was removed in 27 (60%) patients in the opening-wedge group. This difference was significant (p < 0.001).

We conclude that closing-wedge osteotomy achieves a more accurate correction with less morbidity, although both techniques had improved the function of the knee at one year after the procedure.

Arthritic knees, for the purpose of surgical correction during arthroplasty, are generally thought to be either varus knees or valgus knees and soft tissue releases are done in accordance with the same concept. This view is dependent on the clinical deformity in extended knee and the plain AP radiograph of the extended knee. This concept is now challenged by the observations from our study of the arthritic knee kinematics using computer aided navigation when performing total knee replacement arthroplasty. We performed 283 total knee replacements with computer aided navigation. Imageless navigation was used with Stryker and Orthopilot systems. Bone trackers were fixed to the bones and through real time infrared communication the data was collected. The knee kinematics were recorded before and at the end of surgery. This included measurement of biomechanical axis with the knee extended and then gradually flexed. The effect of flexion on the coronal alignment was recorded real time on the computer. The results were then analysed and compared with plain radiographic deformity on long leg films.

Majority of the knees did not behave in a true varus or valgus fashion. We classified the deformity into different groups depending on the behavior of the knee in coronal plane as it moves from extension to flexion. 2 degree was taken as minimum deviation to signify change, as the knee bends from full extension to flexion. The classification system is as follows

Neutral

Deformity - Varus/Valgus to start with in extension

Gp1

Deformity remains the same as the knee flexes

Gp2

Decreasing deformity but does not reach neutral in flexion

Gp3

Decreasing deformity and crosses to opposite (Varus to valgus or valgus to varus) deformity in flexion

Gp4

Deformity first increases and then decreases but does not reach neutral

Traditional releases of medial or lateral structures without realising the true picture of what happens when the knee is flexed, may not be correct. From our study it is clear that not all arthritic varus or valgus knees behave in the same way. Some of the releases we perform conventionally may not be required or need to be modified depending on the knee kinematics.

Abstract. Introduction. This study compared biomechanical and functional parameters of a total knee arthroplasty (TKA) implant (Cemented Zimmer Hi-Flex) against healthy older adults to determine whether knee biomechanics was restored in this patient population. Methodology. Patients with a primary TKA and healthy adults >55 years old with no musculoskeletal deficits or arthritis participated. Bilateral knee range of motion (RoM) was assessed with a goniometer, then gait patterns were analysed with a 3D motion-capture system. An arthrometer then quantified anterior-posterior laxity of each knee. Statistical analyses were performed in SPSS (α=0.05; required sample size: n=21 per group). Results. 25 knees were replaced in 21 patients. Nine presented with fixed flexion deformities (FFD) (13.3±5.6°). FFDs were abolished intraoperatively, and the average flexion increased from 124.8±9.1° to 130.9±5.8°. At 9.6±3.2 years postoperatively, the patients achieved poorer RoM than healthy controls (n=23); p<0.0001. These differences were due to limited flexion in the knee. Patients also failed to achieve the same degree of flexion as controls bilaterally during gait. No differences were observed during mid-flexion; a state that has been associated with instability (p=0.614). There were no differences between groups in knee laxity. Conclusion. Patients in this study had similar gait patterns to healthy older adults during mid-flexion, and were no more likely to exhibit anterior-posterior translation of the knee >7mm; a known risk factor of instability. However, the flexion range was poorer. This led to bilateral pathological knee flexion patterns during gait. Further research should identify the cause of these limitations

Introduction and Objective. Malunion after trauma can lead to coronal plane malalignment in the lower limb. The mechanical hypothesis suggests that this alters the load distribution in the knee joint and that that this increased load may predispose to compartmental arthritis. This is generally accepted in the orthopaedic community and serves as the basis guiding deformity correction after malunion as well as congenital or insidious onset malalignment. Much of the literature surrounding the contribution of lower limb alignment to arthritis comes from cohort studies of incident osteoarthritis. There has been a causation dilemma perpetuated in a number of studies - suggesting malalignment does not contribute to, but is instead a consequence of, compartmental arthritis. In this investigation the relationship between compartmental (medial or lateral) arthritis and coronal plane malalignment (varus or valgus) in patients with post traumatic unilateral limb deformity was examined. This represents a specific niche cohort of patients in which worsened compartmental knee arthritis after extra-articular injury must rationally be attributed to malalignment. Materials and Methods. The picture archiving system was searched to identify all 1160 long leg x ray films available at a major metropolitan trauma center over a 12-year period. Images were screened for inclusion and exclusion criteria, namely patients >10 years after traumatic long bone fracture without contralateral injury or arthroplasty to give 39 cases. Alignment was measured according to established surgical standards on long leg films by 3 independent reviewers, and arthritis scores Osteoarthritis Research Society International (OARSI) and Kellegren-Lawrence (KL) were recorded independently for each compartment of both knees. Malalignment was defined conservatively as mechanical axis deviation outside of 0–20 mm medial from centre of the knee, to give 27 patients. Comparison of mean compartmental arthritis score was performed for patients with varus and valgus malalignment, using Analysis of Variance and linear regression. Results. In knees with varus malalignment there was a greater mean arthritis score in the medial compartment compared to the contralateral knee, with OARSI scores 5.69 vs 3.86 (0.32, 3.35 95% CI; p<0.05) and KL 2.92 vs 1.92 (0.38, 1.62; p<0.005). There was a similar trend in valgus knees for the lateral compartment OARSI 2.98 vs 1.84 (CI −0.16, 2.42; p=0.1) and KL 1.76 vs 1.31 (CI −0.12, 1.01; p=0.17), but the evidence was not conclusive. OARSI arthritis score was significantly associated with absolute MAD (0.7/10mm MAD, p<0.0005) and Time (0.6/decade, p=0.01) in a linear regression model. Conclusions. Malalignment in the coronal plane is correlated with worsened arthritis scores in the medial compartment for varus deformity and may similarly result in worsened lateral compartment arthritis in valgus knees. These findings support the mechanical hypothesis that arthritis may be related to altered stress distribution at the knee, larger studies may provide further conclusive evidence

MOXIMED KineSpring® Knee Implant System is an Orthopaedic device designed for younger or highly active patients with osteoarthritis. The device is placed under the skin, is attached to the tibia and femur, and contains springs which help limit some of the forces that are transmitted through the knee during activities such as walking or running and thereby relieve pain that may be experienced by patients with early arthritis of the knee. The aim of this study is to determine the long term safety and efficacy of the KineSpring knee implant system. This is a prospective case series involving two centres in Glasgow. 29 patients (mean age of 45.1 years and range 18-65 years) were recruited into the study between 2011 and 2016. The Primary outcome measure was Oxford knee score (OKS) at 2, 5 and 10 years post-operatively. Secondary outcome measures include device related complications and survival, patient reported functional outcome measures, patient satisfaction, pain levels and change in radiographic classification of osteoarthritis. At 2-year follow-up, 7 implants were removed (74.1% survival). Complications include deep infection, requiring removal in 1 patient, 2 implant failures requiring removal and one spring breakage. In comparison to pre-operative measures there was an improvement in the pain (3.58 vs. 5.20, p=0.02), stiffness (4.16 vs. 4.47, p=0.6) and OKS (32.4 vs. 36.9, p=0.03). The KineSpring improves overall pain, stiffness and functional outcome at 2 years following surgery, however there was a high rate of removal and further long-term follow up analysis is required regarding its effectiveness

Introduction. Our purpose is to analyze the true costs associated with preoperative CT scans performed for robotic assisted TKA planning and also to determine the value of a formal radiologist reading of these studies. Methods. We reviewed 194 CT scans of 176 sequential patients who underwent primary RTKA by a single surgeon at a suburban teaching hospital. CT radiology reports were reviewed for the presence of incidental findings that might result in change of care to the patient. Actual payments for technical and professional components of the CT scans were retrieved for 170 of the 176 patients. Any patient payments for the CT scan were also recorded. Results. In no CT scan report was there any findings other than arthritis in the knee and nothing was identified that lead to a recommendation for any additional testing. The mean total payment for a preoperative CT scan was $253 (range 0 – 912). The mean technical payment was $206 (range 0 – 856). The mean professional component paid was $48 (range 0 – 66). On average patients personally paid $56 (range 0 – 618). In 99/170 cases (58 %), the patients made no payment. For the remaining 71 patients the mean payment made was $134 (range 10 – 618). Discussion and Conclusion. No CT scan identified any clinical problem other than arthritis – this suggests that the professional component cost of this specific CT scan could be eliminated without harm to patients. The cost of the CT scan – mean <$300 – is low and a minimal part of the total overall cost of a primary TKA. Patients understand the value of the CT scan - preoperative advanced imaging helps ensure a precise and accurate intraoperative experience – and they are willing to pay for any of their costs related to this preoperative test. For figures, tables, or references, please contact authors directly

Introduction. Total knee arthroplasty (TKA) is an effective surgical intervention, which alleviates pain and improves function and health-related quality of life in patients with end-stage arthritis of the knee joint. With improvements in anesthesia, general health care, and surgical techniques, this procedure has become widely accepted for use in very elderly patients. However, many elderly patients tend to have compromised function and low reserve capabilities of organs and are therefore likely to develop various complications during the perioperative period. Thus, elderly patients often hesitate to undergo simultaneous bilateral TKA (SBTKA). Our purpose was to report the short-term results and clinical complications of octogenarians undergoing SBTKA. Materials and Methods. Between 2015 and 2016 all patients greater than 80years of age who underwent SBTKA by a single surgeon were retrospectively evaluated demographics, comorbidity, complications, and 30days mortality following SBTKA. Arthroplasty was performed sequentially under general anesthesia by one team led by primary surgeon. After the first knee, the patient's cardiopulmonary status was assessed by anesthesiology to determine whether or not to begin the second side. Cardiopulmonary decompensation, such as significant shifts in heart rate, oxygen saturation or blood pressure, was not showed. Then the second procedure was undertaken. Inclusion criteria of this study was underlying diseases were osteoarthritis. Exclusion criteria were (1) previous knee surgery; (2) underlying diseases were osteonecrosis, rheumatoid arthritis, fracture, and others. Fifty-seven patients with an average age of 82.7years were identified. The results of these procedures were retrospectively compared with those of patients greater than 80years of age of 89 patients unilateral TKA (UTKA) that had been performed by the same surgeon. Results. The study groups did not differ significantly with regard to age, gender, or body mass index. The mean age was 82.7years with a mean body mass index of 25.8 for the SBTKA group, compared with 84.0years with a mean body mass index of 24.9 for the UBTKA group. The length of hospital stay was longer in SBTKA groups. There was no serious complication. No deaths, no pulmonary embolisms and no nerve paralysis occurred within 30days in both groups. There was one wound problem in SBTKA group, compared 10 wound problem in UBTKA group; this difference was significant. Three deliriums occurred in SBTKA group, compared 13 deliriums in UBTKA group; this difference was significant. Minor complications included urinary tract infection, decubitus ulcer, transfusion reaction and ileus were noted seven in SBTKA group, compared in 11 UBTKA group; this difference was not significant. Conclusions. Complications and mortality are not higher for SBTKA compared to UTKA, SBTKA can be a safe and effective option for octogenarians

Aims. We aimed to describe the epidemiological, biological, and bacteriological characteristics of osteoarticular infections (OAIs) caused by Kingella kingae. Methods. The medical charts of all children presenting with OAIs to our institution over a 13-year period (January 2007 to December 2019) were reviewed. Among these patients, we extracted those which presented an OAI caused by K. kingae and their epidemiological data, biological results, and bacteriological aetiologies were assessed. Results. K. kingae was the main reported microorganism in our paediatric population, being responsible for 48.7% of OAIs confirmed bacteriologically. K. kingae affects primarily children aged between six months and 48 months. The highest prevalence of OAI caused by K. kingae was between seven months and 24 months old. After the patients were 27 months old, its incidence decreased significantly. The incidence though of infection throughout the year showed no significant differences. Three-quarters of patients with an OAI caused by K. kingae were afebrile at hospital admission, 11% had elevated WBCs, and 61.2% had abnormal CRPs, whereas the ESR was increased in 75%, constituting the most significant predictor of an OAI. On MRI, we noted 53% of arthritis affecting mostly the knee and 31% of osteomyelitis located primarily in the foot. Conclusion. K. kingae should be recognized currently as the primary pathogen causing OAI in children younger than 48 months old. Diagnosis of an OAI caused by K. kingae is not always obvious, since this infection may occur with a mild-to-moderate clinical and biological inflammatory response. Extensive use of nucleic acid amplification assays improved the detection of fastidious pathogens and has increased the observed incidence of OAI, especially in children aged between six months and 48 months. We propose the incorporation of polymerase chain reaction assays into modern diagnostic algorithms for OAIs to better identify the bacteriological aetiology of OAIs. Cite this article: Bone Joint J 2021;103-B(3):578–583

Introduction. Although total knee replacement became a widespread procedure for the purpose of knee reconstruction, osteotomies around the knee were regularly performed. Total knee arthroplasty should be performed for advanced arthritis of the knee. With the advent of biplanar open wedge high tibial osteotomy (HTO) combined with locking plate fixation, HTO has been expanded and its surgical outcome has been improved in recent years. However, post-operative joint-line obliquity has been raised as a concern with this procedure, which may affect the outcome especially in the knees with severe varus deformity. Hence the purpose of this study is to analyze the compression and shear stresses in the knee cartilage with joint line obliquity after HTO. Methods. Using a three-dimensional computer aided design software, the digital knee model with soft tissues was developed. The geometrical bone data used in this study were derived from commercially available human bone digital anatomy media (3972 and 3976, Pacific Research Laboratories, Inc., WA, USA). The three-dimensional knee model was transferred to finite element model. Material properties of the soft tissues and bones were derived from previous studies. The loading condition was adjusted to the load during a single-leg stance of the gait cycle, which resulted in an axial compressive load of 1200 N. Two different conditions were subjected to the analysis: normal alignment and joint-line obliquity after HTO. For the normal alignment, a static force of 1200 N was applied along the mechanical axis. For the joint-line obliquity models, a single force of 1200 N was applied rotating force directions in the frontal plane from the normal direction by 2.5º, 5º, 7.5º, and 10º, respectively. Results. The maximum values of the axial stresses in the cartilages for the normal condition showed almost same values in medial and lateral compartments. In the joint-line obliquity models, the maximum axial stress values in the medial compartment did not exhibit substantial change up to the level of 7.5º obliquity, while a rise in maximum stress value was observed for the model with 10º obliquity. The shear stress showed a different tendency. In the joint-line obliquity models, a steep rise of laterally directed shear stress in the medial compartment was observed for models with obliquity of 5º or more. Discussion. The shear stress in the medial cartilage increased to almost twice as high as the normal knee level for the joint- line obliquity model with an inclination of 5º. The maximum shear stress values increased in accordance with the obliquity angle. The elevated stress could be deleterious to the cartilage. In such large amount of correction by tibial osteotomy leads to unfavorable mechanical environment in the knee. For those severe situations, double-level osteotomy, which retains anatomical knee joint line by simultaneous femoral and tibial osteotomies, should be considered to correct the joint-line obliquity