Patterns of Compartment Involvement in End-stage Knee Osteoarthritis in a Chinese Orthopedic Center: Implications for Implant Choice

Unicompartmental knee arthroplasty vs high tibial osteotomy for knee osteoarthritis: A comparison of clinical and radiological outcomes

BACKGROUND

Unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) are well-established operative interventions in the treatment of knee osteoarthritis. However, which intervention is more beneficial to patients with knee osteoarthritis remains unknown and a topic of much debate. Simultaneously, there is a paucity of research assessing the relationship between radiographic parameters of knee joint alignment and patient-reported clinical outcomes, preoperatively and following HTO or UKA.

AIM

To compare UKAs and HTOs as interventions for medial-compartment knee osteoarthritis: Examining differences in clinical outcome and investigating the relationship of joint alignment with respect to this.

METHODS

This longitudinal observational study assessed a total of 42 patients that had undergone UKA (n = 23) and HTO (n = 19) to treat medial compartment knee osteoarthritis. Patient-reported outcome measures (PROMs) were collected to evaluate clinical outcome. These included two disease-specific (Knee Injury and Osteoarthritis Outcome Score, Oxford Knee Score) and two generic (EQ-5D-5L, Short Form-12) PROMs. The radiographic parameters of knee alignment assessed were the: Hip-knee-ankle angle, mechanical axis deviation and angle of Mikulicz line.

RESULTS

Statistical analyses demonstrated significant (P < 0.001), preoperative to postoperative, improvements in the PROM scores of both groups. There were, however, no significant inter-group differences in the postoperative PROM scores of the UKA and HTO group. Several significant correlations associated a more distolaterally angled Mikulicz line with worse knee function and overall health preoperatively (P < 0.05). Postoperatively, two clusters of significant correlations were observed between the disease-specific PROM scores and knee joint alignment parameters (hip-knee-ankle angle, mechanical axis deviation) within the HTO group; yet no such associations were observed within the UKA group.

CONCLUSION

UKAs and HTOs are both efficacious operations that provide a comparable degree of clinical benefit to patients with medial compartment knee osteoarthritis. Clinical outcome has a limited association with radiographic parameters of knee joint alignment postoperatively; however, a more distolaterally angled Mikulicz line appears associated with worse knee function/health-related quality of life preoperatively.

A proposed modification to the Kellgren and Lawrence classification for knee osteoarthritis using a compartment-specific approach

Purpose

Since Kellgren and Lawrence (KL) originally classified knee osteoarthritis, several authors have reported varying levels of reliability and a lack of uniformity in the use of this classification system. We propose several modifications to the KL classification including the use of a compartment-specific approach that we hypothesize will lead to a better understanding of knee OA while maintaining an adequate interobserver and intraobserver reliability.

Methods

We propose the addition of the lateral and skyline-view radiographs to the standard anteroposterior (AP) and lateral projections in the evaluation. Also suggest a more precise definition of the evaluated parameters; the addition of the subchondral cancellous bone as parameter of evaluation; and the assessment of medial tibiofemoral compartment (MTFC), lateral tibiofemoral compartment (LTFC) and patellofemoral compartment (PFC) separately resulting in a compartment-specific KL staging score rather than a single overall KL score. Six evaluators (two knee surgeons, two radiologists and two knee fellows) used the modified KL classification to classify 230 randomly selected knees on two separate occasions. Reliabilities were assessed by calculating Krippendorff's ⍺ coefficients.

Results

Two hundred and ten knees were included for final evaluation and analyses (53% left knees; 65% females; mean age 56 years old). Average interobserver reliability was moderate for all compartments (0.51 for the MTFC; 0.51 for the LTFC; and 0.56 for the PFC). Average intraobserver reliability was substantial for all compartments (0.63 for the MTFC; 0.65 for the LTFC; and 0.7 for the PFC). Experienced evaluators showed a higher intraobserver reliability than less-experienced evaluators.

Conclusions

A modified compartment-specific KL classification enables a practical and detailed description of knee OA involvement and demonstrates acceptable interobserver and intraobserver reliability. Level of Evidence: Level III.

Tibiofemoral Load Magnitude and Distribution During Load Carriage

Chronic exposure to high tibiofemoral joint (TFJ) contact forces can be detrimental to knee joint health. Load carriage increases TFJ contact forces, but it is unclear whether medial and lateral tibiofemoral compartments respond similarly to incremental load carriage. The purpose of our study was to compare TFJ contact forces when walking with 15% and 30% added body weight. Young healthy adults (n = 24) walked for 5 minutes with no load, 15% load, and 30% load on an instrumented treadmill. Total, medial, and lateral TFJ contact peak forces and impulses were calculated via an inverse dynamics informed musculoskeletal model. Results of 1-way repeated measures analyses of variance (α = .05) demonstrated total, medial, and lateral TFJ first peak contact forces and impulses increased significantly with increasing load. Orthogonal polynomial trends demonstrated that the 30% loading condition led to a curvilinear increase in total and lateral TFJ impulses, whereas medial first peak TFJ contact forces and impulses responded linearly to increasing load. The total and lateral compartment impulse increased disproportionally with load carriage, while the medial did not. The medial and lateral compartments responded differently to increasing load during walking, warranting further investigation because it may relate to risk of osteoarthritis.

Can isokinetic test be a supportive tool for unilateral knee arthroplasty decision?

Objectives

This study analyzed whether the isokinetic muscle strength of bilateral knee osteoarthritis patients undergoing unilateral total knee arthroplasty (TKA) is a predictor for prior surgery side.

Patients and methods

In the prospective study conducted between April 2021 and December 2021, 58 knees of 29 unilateral TKA candidates (6 males, 23 females; mean age: 66.7±7.4 years; range, 53 to 81 years) were enrolled. The patients were divided into surgical (n=29)and nonsurgical (n=29) groups. The knees of patients with bilateral knee osteoarthritis (Stage III or IV) according to the Kellgren-Lawrence (KL) scale were scheduled for unilateral TKA. An isokinetic testing system was used to assess knee flexor and extensor muscle strength (peak torque) at angular velocities of 60°/sec and 180°/sec (five cycles per velocity). The radiological (X-ray-based KL scale and magnetic resonance imaging-based quadriceps angle) and clinical findings (isokinetic test and Visual Analog Scale pain scores) in both groups were compared.

Results

The mean symptom duration was 10±5.4 years. The KL score and quadriceps angle showed no significant differences (p=0.056 and p=0.663, respectively). Isokinetic test results were in accordance with the clinical results of the surgery group. In the isokinetic evaluation, both the 60°/sec concentric extension (35.00 vs. 46.00, p=0.002) and flexion peak torque (18.00 vs. 26.00, p=0.001) values were significantly lower in the surgical group than in the nonsurgical group.

Conclusion

Isokinetic testing can be a supportive tool for assessing the prior side of TKA in patients with bilateral knee osteoarthritis. Further studies are required to support these findings.

Femoral Cartilage Thickness in Knee Osteoarthritis Patients and Healthy Adults: An Ultrasound Measurement Comparison

Background

Currently, conventional radiography is still widely used to diagnose knee osteoarthritis and assess the grade according to Kallgren and Lawrence's criteria. Ultrasound is a simple, inexpensive, noninvasive, and dynamic modality for evaluating femoral cartilage (FC) thickness. This study aims to measure the FC thickness in knee osteoarthritis (OA) patients and compare it to healthy adults using ultrasound assessment.

Methods

An observational study with a cross-sectional design was conducted at the Department of Physical Medicine and Rehabilitation of Hajj General Hospital, Surabaya, Indonesia, from May to July 2022. Participants radiologically diagnosed with OA were included in the study and assigned to the OA group. Meanwhile, healthy adults without knee symptoms were included in the control group. FC thickness was measured using ultrasound scans at three sites: medial condyle (MC), intercondylar (IC), and lateral condyle (LC) on both sides of the knee.

Results

The mean age in the OA and control groups was 61.03 ± 8.6 and 33.93 ± 14.7 years, respectively. Most participants in both groups were female. The OA group exhibited a thinner FC (1.49-1.63 mm) than the control group (1.68-1.87 mm). There was a significant difference in the mean of the right and left MC in both groups (p < 0.05) but no significant difference in the IC and LC.

Conclusion

OA patients exhibited a thinner FC than healthy adults in the control group. There was a significant difference in the mean thickness of the MC between groups.

[Research progress of failure and revision of unicompartmental knee arthroplasty]

Objective

To conclude the failure factors of unicompartmental knee arthroplasty (UKA), and summarize the research progress of revision surgery.

Methods

The literature on UKA at home and abroad in recent years was reviewed to summarize its risk factors, treatment methods, including the evaluation of bone loss, prosthesis selection, and surgical techniques.

Results

The factors inducing UKA failure mainly include improper indications, technical errors, and others. The application of digital orthopedic technology can reduce failures caused by surgical technical errors and shorten the learning curve. There are a variety of options for revision surgery after UKA failure, including polyethylene liner replacement, revision with UKA or total knee arthroplasty, with adequate preoperative evaluation prior to implementation. The biggest challenge in revision surgery is the management and reconstruction of bone defects.

Conclusion

There is a risk of failure in UKA, which needs to be treated with caution and should be determined according to the type of failure.

Image-based robot assisted bicompartmental knee arthroplasty versus total knee arthroplasty

OBJECTIVE

To evaluate the short-term clinical outcomes of image-based robot-assisted bicruciate retaining bicompartmental knee arthroplasty and compare it to robot-assisted total knee arthroplasty in the Indian population.

METHODS

Between December 2018 and November 2019, five patients (six knees) underwent robot-assisted bicompartmental knee arthroplasty (BCKA). These patients were demographically matched with five patients (six knees) who underwent robot-assisted total knee arthroplasty (TKA) during the same period. Clinical outcomes of these twelve knees were assessed in the form of knee society score (KSS) score, Oxford knee score (OKS), and forgotten joint score (FJS) after a minimum follow-up period of 25 months. The data between the two cohorts were compared and analyzed.

RESULTS

Scores obtained from both cohorts were subjected to statistical analysis. SPSS software was utilized and the Mann Whitney U-test was utilized to compare the two groups. There was no statistically significant difference found between the two groups in terms of functional outcome.

CONCLUSION

Image-based robot-assisted BCKA is a bone stock preserving and more physiological procedure which can be a promising alternative to patients presenting with isolated arthritis of only two compartments of the knee. Although long-term, larger trials are warranted to establish it as an alternative, our pilot study shows an equally favorable outcome as TKA, making it an exciting new avenue in the field of arthroplasty.

Unicompartmental Knee Arthroplasty Has Lower Infection, Conversion, and Complication Rates Compared to High Tibial Osteotomy

INTRODUCTION

 Isolated medial knee osteoarthritis can be surgically treated with either unicompartmental knee arthroplasty (UKA) or high tibial osteotomy (HTO). Proponents of UKA suggest superior survivorship, while HTO offers theoretically improved alignment and joint preservation delaying total knee arthroplasty (TKA). Therefore, we compared complications in a large population of patients undergoing UKAs or HTOs. We specifically assessed 90 days, 1 year, and 2 years: (1) periprosthetic joint infection (PJI) rates, (2) conversion to TKA rates, as well as (3) complication rates.

METHODS

 A review of an administrative claims database was used to identify patients undergoing primary UKA (n = 13,674) or HTO (n = 1,096) from January 1, 2010 to December 31, 2019. Complication rates at 90 days, 1 year, and 2 years were compared between groups using unadjusted odds ratios (ORs) with 95% confidence intervals. Subsequently, multivariate logistic regressions were performed for PJI and conversion to TKA rates.

RESULTS

 At all time points, patients who underwent UKA were associated with lower rates of infection compared with those who underwent HTOs (all OR ≤ 0.51, all p ≤ 0.010). After 1 year, patients who received UKAs were found to have lower risk of requiring a conversion to a TKA versus those who received HTOs (all OR ≤ 0.55, all p < 0.001). Complications such as dislocations, periprosthetic fractures, and surgical site infections were found at lower odds in UKA compared with HTO patients.

CONCLUSION

 This study provides large-scale analyses demonstrating that UKA is associated with lower infection rates and fewer conversions to TKA compared with patients who have undergone HTO. Dislocations, periprosthetic fractures, and surgical site infections were also found to be lower among UKA patients. However, with careful patient selection, good results and preservation of the native knee are achieved with HTOs. Therefore, UKA versus HTO may be an important discussion to have with patients in an effort to lower the incidence of postoperative infections and complications.

Safety and Efficacy of Single Condylar Knee Prosthesis When Treating Knee Single Compartment Osteoarthritis: A Prospective, Case-Randomized Controlled Study

Objective. The aim of this study is to explore the safety and efficacy of single condylar knee prosthesis when treating knee single compartment osteoarthritis by measuring the decrease of hemoglobin, total postoperative blood loss, maximum reduction of HCT, and knee joint activity. Methods. A total of 80 patients with knee joint single compartment osteoarthritis treated in our hospital from January 2020 to December 2021 were studied. They were randomly assigned to a study group (n = 40) and a control group (n = 40). The study group was treated with total knee prosthesis, while the control group was treated with simple knee prosthesis. The decrease rate of hemoglobin, the amount of bleeding, and the maximum decrease of hematocrit were compared after treatment. The range of motion of knee joint was evaluated by the Fugl-Meyer motor function scale (FM-B) and Berg balance scale (BBS). Results. The decrease of hemoglobin in the study group at 24 hours, 36 hours, and 48 hours after treatment was remarkably lower ( $P$  < 0.05). The total blood loss and the maximum reduction of hematocrit(HCT) in the study group were lower ( $P$  < 0.05). The range of motion (ROM) of the knee joint in the study group at 6 and 12 months after treatment was remarkably higher than that before treatment and remarkably higher compared to the control group ( $P$  < 0.05). The FM-B scale and BBS scale of the studied cohort at 6 and 12 months after treatment were remarkably higher than those before treatment and were remarkably higher compared to the control’s ( $P$  < 0.05). Conclusion. The unicondylar knee prosthesis is safer and more effective in the treatment of noncompartmental osteoarthritis of the knee, facilitating less trauma and perioperative blood loss and enhancing the patient’s motion and balance.

Traditional Chinese Acupressure Massage of the Quadriceps Femoris Can Relieve Flexion Pain after Undergoing Total Knee Arthroplasty

Objective

To reduce the pain of quadriceps during knee flexion after total knee arthroplasty and increase range motion of knee flexion.

Design

Three-month prospective before/after quality improvement project. Setting. Department of Bone and Joint Surgery. Participants. A total of 80 patients who met the surgical indications were admitted to the outpatient department for surgery. They were randomly grouped by computer in advance, and the patients were divided into two groups according to the time of admission, each with 40 cases. Intervention. The intervention group performed routine rehabilitation exercises and received quadriceps acupoint massages for 20 minutes twice a day for two consecutive weeks. The control group performed routine rehabilitation exercises, such as gentle quadriceps massage for 20 minutes twice a day for two consecutive weeks. Main Outcome Measures. PPT (pressure pain threshold) of quadriceps femoris/VAS (visual analog scale) of knee flexion and motion of knee flexion.

Results

The VAS score, range of motion, and tenderness threshold during flexion were significantly better in the intervention group than in the control group at 1, 2, and 4 weeks after surgery. But the VAS score, range of motion, and tenderness threshold did not significantly differ between groups at 12 weeks after surgery.

Conclusion

Acupoint massage of the quadriceps femoris can relieve early flexion pain in patients after total knee arthroplasty. The trial was registered at clinical trials.gov.

Comparison of computer-assisted navigated technology and conventional technology in unicompartmental knee arthroplasty: a meta-analysis

Background

Though unicompartmental knee arthroplasty (UKA) is a useful procedure to treat knee osteoarthritis, it remains a great controversial point as to if navigated systems are able to achieve better accuracy of limb alignment and greater clinic results. Current meta-analysis was conducted to explore if better clinical outcomes and radiographic outcomes could be acquired in the navigated system when compared with conventional procedures.

Methods

We identified studies in the online databases, including Medline, Embase, the Cochrane Library and Web of Science before May 2021. The PRISMA guidelines in this report were strictly followed. Our research was completed via Review Manager 5.4 software.

Results

Fourteen articles were included, involving 852 knees. The present meta-analysis displayed that the navigated system had remarkably improved outcomes in inliers of mechanical axis (MA) (P < 0.01), MA in the Kennedy's central zone (Zone C) (P = 0.04), inliers of the coronal femoral component (P < 0.01), inliers of the coronal tibial component (P = 0.005), inliers of the sagittal femoral component (P = 0.03), inliers of the sagittal tibial component (P = 0.002) and Range Of Motion (ROM) (P = 0.04). No significant differences were observed in Oxford Knee Score (OKS) (P = 0.15), American Knee Society Knee Score (KSS score) (P = 0.61) and postoperative complications (P = 0.73) between these 2 groups. Regarding operating time, the navigated group was 10.63 min longer in contrast to the traditional group.

Conclusion

Based on our research, the navigated system provided better radiographic outcomes and no significant difference in the risk of complications with longer surgical time than the conventional techniques. But no significant differences were found in functional outcomes. Because the included studies were small samples and short-term follow-up, high-quality RCTs with large patients and sufficient follow-up are required to identify the long-term effect of the navigated system.

Clinical and functional evaluation of bone marrow aspirate concentrate vs autologous conditioned serum in the treatment of knee osteoarthritis

BACKGROUND AND AIM

The aim of this study was to compare the efficacy of a single Bone Marrow Aspirate Concentrate (BMAC) with a cycle of 4 Autologous Conditioned Serum (ACS) injections in the treatment of early-stage knee osteoarthritis (OA).

METHODS

Two groups of 12 patients with degenerative knee OA were treated with a single BMAC injection and with a cycle of 4 ACS injections respectively. Follow-up was set at baseline (t0), one-month (t1) and six-months (t2) evaluating VAS for pain, WOMAC index and range of motion (ROM).

RESULTS

We reported a significant improvement in WOMAC after BMAC injection both at t1 (p= 0,001) as well as t2 (p< 0,001), plus a reduction of VAS values in BMAC group at six months follow-up (p = 0,024). In contrast, no significant differences in ROM between the two groups were observed.

CONCLUSIONS

Both the approaches are safe and effective in the treatment of knee OA, with a major efficacy of BMAC.

A Retrospective Chart Review of 122 Inpatients with Knee Osteoarthritis Treated with Korean Medicine: An Analysis of the Effects of Treatment

Background: Korean medicine treatment was assessed in patients with knee osteoarthritis (OA) according to subgroups of: sex, age, cause of knee OA, body mass index, hospitalization period, history, OA compartment, phenotype, and comorbidity. Methods: A retrospective review was performed of 122 inpatients who were admitted to the Hospital of Korean Medicine for Korean medicine treatment of knee pain, and were diagnosed with knee OA based on magnetic resonance imaging findings. Analysis of patient subgroups (sex, age, cause of knee OA, body mass index, hospitalization period, history, OA compartment, phenotype, and comorbidity) was carried out and treatments including acupuncture, cupping, pharmacopuncture, herbal medicine, chuna therapy, medicinal steaming therapy, manual therapy, and extracorporeal shock wave therapy were listed. The numeric rating scale (NRS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 5-level EuroQol- 5 Dimension (EQ-5D-5L) scores were measured before and after treatment to assess the effects of treatment on pain and quality of life. Results: Seventeen males and 105 females were included in this study. Most patients were in their 60s. In the total study population, NRS, WOMAC, and EQ-5D-5L scores were improved statistically significant when comparing before and after treatment. The NRS and WOMAC scores improved statistically significant in the medial, patellofemoral, medial + patellofemoral, medial + lateral + patellofemoral compartment. Conclusion: Korean medicine treatment significantly reduced pain, stiffness, and physical dysfunction, and improved the quality of life of patients with knee OA, suggesting that it may be an effective alternative to the current conservative treatments.

Does bicompartmental knee arthroplasty hold an advantage over total knee arthroplasty? Systematic review and meta-analysis

INTRODUCTION

The role of bicompartmental knee arthroplasty (BKA) in the treatment of medial patellofemoral osteoarthritis (MPFOA) has been debated by orthopaedic surgeons for years. The BKA is a cruciate ligament retaining prosthesis designed to mimic the kinematics of the native knee that requires resurfacing of only two knee compartments. In this study, we aim to assess the patient recorded outcome measures (PROMs), range of motion (ROM), perioperative morbidity, and implant revision rate in patients undergoing BKA and compare them to those undergoing total knee arthroplasty (TKA) for bicompartmental knee osteoarthritis (OA).

PATIENTS AND METHODS

We followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses Statement (PRISMA). Articles from any country and written in any language were considered. We included all randomized control trials and retrospective cohort studies examining BKA versus TKA for bicompartmental knee OA. The primary outcome measure was knee society score (KSS) at one year and the secondary outcome measures were Oxford knee score (OKS) and short-form survey (SF-)12 at six and twelve months.

RESULTS

We included five studies in our meta-analysis. In terms of OKS, KSS, and SF-12, our meta-analysis suggests better short-term results for the TKA compared with the BKA. TKA was also associated with a shorter operative time and a lower revision rate. The BKA implant did however result in marginally less intraoperative blood loss and slightly better post-operative ROM.

CONCLUSIONS

BKA did not prove to be an equivalent alternative to TKA in bicompartmental knee OA. It was associated with inferior KSS, OKS, and SF-12 at short-term follow-up and a higher revision rate.

The compartmental distribution of knee osteoarthritis - a systematic review and meta-analysis

OBJECTIVES

For a population with knee osteoarthritis (OA), determine: 1) the prevalence of single compartmental, bicompartmental and tricompartmental OA, 2) the prevalence of isolated medial tibiofemoral, lateral tibiofemoral, or patellofemoral OA, and combinations thereof.

METHODS

PubMed and Web of Science databases, and reference lists of identified studies, were searched to find studies which reported on the compartmental distribution and prevalence of knee OA. Two independent reviewers assessed studies against pre-defined inclusion criteria and prevalence data were extracted along with subject characteristics. The methodological quality of each included study was assessed. A random-effects model meta-analysis was performed for each OA category to estimate the relative prevalence of OA in the knee compartments amongst people with knee OA.

RESULTS

16 studies (3,786 knees) met the inclusion criteria. High heterogeneity was measured. Normalised for knees with OA, estimated prevalence rates (95% CI) were: single compartmental 50% (31.5-58.3%), bicompartmental 33% (23.1-37.2%) and tricompartmental only 17% (8.8-24.8%). Isolated medial tibiofemoral OA, isolated patellofemoral OA, and combined medial tibiofemoral and patellofemoral OA were more common than tricompartmental disease, occurring in 27% (15.2-31.1%), 18% (9.9-22.7%) and 23% (14.1-27.3%) of people respectively. Single/bicompartmental patterns of disease involving the lateral tibiofemoral compartment were less common, summing to 15% (8.5-18.7%).

CONCLUSION

Three-quarters of people with knee OA do not have tricompartmental disease. This is not reflected in the frequency with which partial and combined partial knee arthroplasties are currently used.

TRIAL REGISTRATION NUMBER

PROSPERO systematic review protocol (CRD42019140345).

Do Knee Osteoarthritis Patterns Affect Patient-Reported Outcomes in Total Knee Arthroplasty? Results From an International Multicenter Prospective Study With 3-Year Follow-Up

BACKGROUND

The aim of this multicenter study is to answer (1) Does patellofemoral osteoarthritis (OA) affect preoperative Knee Injury and Osteoarthritis Outcome Score (KOOS) scores in total knee arthroplasty (TKA)? and (2) Do different OA patterns affect preoperative and postoperative KOOS scores in TKA?

METHODS

This international, multicenter prospective study examined 384 TKA patients. Compartmental OA was divided into (1) medial, (2) medial + patellofemoral, (3) lateral, (4) lateral + patellofemoral, (5) medial + lateral (bicompartmental), and (6) medial + lateral + patellofemoral (tricompartmental), based on preoperative anterior-posterior and lateral ± skyline radiographs with Kellgren-Lawrence grade III-IV and joint space width <2.5 mm. KOOS was collected preoperatively, 1 year postoperatively, and 3 years postoperatively. Higher KOOS score represented better clinical state, for example, higher KOOS Pain score indicated less pain.

RESULTS

Patellofemoral OA had no effect on preoperative KOOS scores (P > .15). Compared to medial ± patellofemoral OA patients, bicompartmental/tricompartmental OA patients had less preoperative pain (KOOS Pain 7.4, P = .03) and higher daily function (KOOS-ADL [Activities of Daily Living] 7.1, P = .05), and higher 1-year postoperative daily function (KOOS-ADL 9.2, P = .03) and sports activity (KOOS Sports & Recreation Function 15.0, P = .04), while lateral ± patellofemoral OA patients had more symptoms (KOOS-Symptoms 7.0, P < .01), more pain (KOOS-Pain 7.5, P = .01), lower daily function (KOOS-ADL 9.3, P < .01), and lower quality of life (KOOS-QOL 9.0, P = .04), at 3 years postoperatively.

CONCLUSION

Patellofemoral OA does not affect medial ± lateral OA patients' preoperative KOOS scores, challenging the importance of patellofemoral OA in TKA. Lateral ± patellofemoral OA patients have lower postoperative KOOS scores than medial/more progressed compartmental OA patients, indicating that patients with less common OA patterns present with unique surgical challenges. Further development of indications for and correct timing of TKA surgery in different patient subgroups is needed.

Acceptable outcomes with unicompartmental knee replacement and PCL deficiency are achievable: a case series of nine patients

PURPOSE

Posterior cruciate ligament (PCL) deficiency is considered to be a contraindication for unicompartmental knee replacement (UKR); however, there is no evidence to support or contradict this. There are occasional circumstances where UKR in PCL deficient patients have been performed where the patient otherwise satisfies the indications for UKR. The aim of this paper is to describe the outcome of UKR in PCL deficient patients.

METHODS

A retrospective study of patients with painful medial compartment osteoarthritis and PCL deficiency treated with Oxford UKR between 2006 and 2015 was undertaken. Clinical records from a prospectively recorded database were reviewed and outcomes were assessed based on revision rate, Oxford Knee Score (OKS), American Knee Society score and Tegner Activity Score.

RESULTS

Nine patients were identified. The median age at surgery was 51 years (range 42-80) and median follow-up was 6 years (range 1-10). There was one bearing dislocation requiring open exchange. The outcome of seven patients was excellent (OKS > 41). Two patients, who were both elderly, had good outcomes (OKS 41 and 39). One patient had a poor outcome, but it is not clear if this was related to the knee as she had a learning disability and examination and radiographs of the knee were satisfactory.

CONCLUSION

The results of this small series suggest that excellent results can be achieved with UKR for selected patients with medial osteoarthritis in a PCL deficient knee that was functioning well before the osteoarthritis developed. On the basis of this a larger study should be undertaken. Until more results are available PCL deficiency should be considered a relative contra-indication to UKR.

LEVEL OF EVIDENCE

IV.

Does mobile-bearing have better flexion and axial rotation than fixed-bearing in total knee arthroplasty? A randomised controlled study based on gait

Objective

To analyse the 6 degrees of freedom of the knee and gait data of patients with medial knee osteoarthritis before and after fixed-bearing (FB) and mobile-bearing (MB) total knee arthroplasty (TKA) ​and examine the influence of TKA on gait characteristics and the difference between FB and MB prosthesis. We also sought to explore the prosthesis options available for TKA in these patients.

Methods

Thirty patients who underwent TKA at the Department of Orthopedics at our hospital from June to October 2017 were included. All patients had a lower limb mechanical axis (hip-knee-ankle angle) of less than 180° which were regarded as genu varum knees and had medial knee osteoarthritis. Patients were randomised divided into the FB group ​and the MB group according to the knee prosthesis implanted. An infrared navigation three-dimensional portable knee motion analysis system (Opti-Knee®, Shanghai Innomotion, Inc.) was used to acquire data on the 6 degrees of freedom of both knees when walking on flat ground before and after surgery (angle of tibia relative to femur parameters: flexion-extension, internal rotation–external rotation, abduction–adduction; displacement parameters: anterior–posterior, proximal–distal, medial–lateral). Postoperative follow-up efficacy was assessed using the Oxford Knee Score system.

Results

There were significant differences in the maximum values of the internal/external rotation and flexion/extension angle between patients post-TKA and the healthy population, p values were 0.007 and <0.001,respectively. The postoperative maximum values of genu varum and internal rotation in both FB [(−9.49 ​± ​5.99°), (−5.77 ​± ​3.42°), respectively] and MB [(−9.64 ​± ​4.83°), (−7.54 ​± ​4.51°), respectively] groups were lower than the preoperative ones [FB (−15.13 ​± ​6.78°), (−8.28 ​± ​4.83°); MB (−13.28 ​± ​3.98°), (−9.46 ​± ​4.99°), respectively] (p ​≤ ​0.001), while the postoperative maximum values of flexion angle and anterior displacement in both FB [(46.11 ​± ​4.14°), (0.71 ​± ​0.35 ​cm), respectively] and MB [(49.33 ​± ​3.98°), (0.75 ​± ​0.89 ​cm), respectively] groups were larger than the preoperative ones [FB (43.15 ​± ​3.77°), (0.26 ​± ​0.74 ​cm); MB (44.62 ​± ​5.92°), (0.33 ​± ​0.79°), respectively] (p ​≤ ​0.001). The postoperative range of flexion/extension angle in both FB (40.13 ​± ​4.14°) and MB (45.82 ​± ​3.76°) groups was significantly larger than the preoperative one [FB (36.17 ​± ​6.07°), MB (37.09 ​± ​3.93°), respectively] (p ​≤ ​0.001). There were also significant increases in range of anterior–posterior displacement in the FB group (0.85 ​± ​0.32 ​cm) postoperatively compared with the preoperative one (0.71 ​± ​0.92 ​cm) (p ​= ​0.016) ​and significant increases in range of medial-lateral displacement (0.64 ​± ​0.73 ​cm) in the MB group postoperatively compared with the preoperative one (0.52 ​± ​0.91 ​cm) (p ​= ​0.025). The mean flexion/extension angle of the MB group was significantly greater than the FB group after surgery in both the stance phase and the swing phase (p ​< ​0.001). There were significant differences in postoperative knee axial rotation during the gait cycle between the MB and FB groups (p ​= ​0.028) ​and that postoperative internal rotation of the tibia relative to the femur increased in the MB group. The Oxford Knee Score at the last follow-up visit about 7.5 months after surgery was 15.6 ​± ​1.3 and 15.1 ​± ​1.1 points for FB and MB groups, respectively. This difference was not significant (p ​= ​0.428).

Conclusions

TKA can make the parameters of knee gait characteristics closer to the normal population. Medial knee osteoarthritis patients who received a MB prosthesis in TKA had better joint flexion function and axial rotation than the FB one. However, there is insufficient evidence to suggest that the MB prosthesis is a better option for patients with medial knee osteoarthritis.

The translational potential of this article

To date, no consensus for prosthesis selection in TKA has been established. This study found significant differences in joint flexion/extension angle and internal/external rotation during gait post-TKA surgery in medial knee osteoarthritis patients who received different prostheses. This will provide some references for prosthesis selection for a large number of genu varum patients in clinical practice.

Anatomical Adaptation of Fibula and its Mechanism of Proximal Partial Fibulectomy Associated with Medial Compartment Knee Osteoarthritis

Objectives

To reveal the anatomical adaptation of the fibula and its relations to age and settlement of the medial tibial plateau, and to explore the mechanism of proximal partial fibulectomy in treating medial compartment knee osteoarthritis (OA).

Methods

A retrospective study was performed in the Third Hospital of Hebei Medical University. Weight‐bearing full‐leg anteroposterior (AP) radiographs of 280 adults (560 knees) obtained from 1 January 2018 to 31 October 2018 were enrolled according to our inclusion and exclusion criteria, including 157 men and 123 women, with an average age of 50.3 ± 14.8 years (range, 19–80 years). Radiographic severity of knee OA was assessed using Kellgren and Lawrence (K–L) grading. The settlement of the medial tibial plateau was evaluated using the medial proximal tibial angle (MPTA). Curvatures of the tibia and the fibula were measured as proximal tibial curvature (PTC), distal tibial curvature (DTC), proximal fibular curvature (PFC), and distal fibular curvature (DFC). Two orthopaedic surgeons performed all the radiological measurements for 30 randomly selected patients, and repeated the measurements 1 week later. Based on the satisfactory intra‐observer and inter‐observer reliabilities (ICC > 0.9), each parameter was analyzed in this study. Multivariable linear regression models were used to examine relations between radiological measurements and age.

Results

The mean MPTA, PTC, DTC, PFC, and DFC were 85.4° ± 2.8°, 176.2° ± 1.9°, 176.8° ± 1.8°, 176.8° ± 1.9°, and 177.0° ± 2.0°, respectively. Ninety‐three knees of K–L grade I were categorized as non‐knee OA, and 467 knees of K–L grades II–IV were categorized as knee OA. The MPTA, PTC, and PFC of the knee OA group were significantly smaller than those of non‐knee OA group (P < 0.05). The K–L grade of knee OA significantly increased with age (χ² = 182.169, P < 0.01). The multivariate linear regression analysis indicated that the MPTA and fibular curvatures were negatively correlated with age (the regression equation is age = 561.165–0.945 MPTA‐0.937 PFC‐0.959 DFC, P < 0.05), and the MPTA was negatively correlated with PFC (the regression equation is MPTA = 7.827 + 0.099 DFC, P < 0.05).

Conclusions

The proximal curve of the fibula increased in patients with medial compartment knee OA, and this change was positively correlated with age and settlement of the medial tibial plateau. This anatomical adaptation of the fibula was associated with greater fibular axial load and the pulling from the peroneus longus. The proximal partial fibulectomy procedure effected a receptive foot pronation to reduce KAM and rebalance the biceps‐proximal fibula–peroneus longus complex, consequently achieving medial compartment unloading.