Mobile-bearing unicompartmental knee arthroplasty in old-aged patients demonstrates superior short-term clinical outcomes to open-wedge high tibial osteotomy in middle-aged patients with advanced isolated medial osteoarthritis

Simultaneous bilateral open wedge high tibial osteotomy versus simultaneous bilateral unicompartmental knee arthroplasty in the treatment of bilateral medial knee osteoarthritis: a retrospective study of an average three-year follow-up

OBJECTIVE

There is growing evidence that simultaneous bilateral open wedge high tibial osteotomy(SBOWHTO) and simultaneous bilateral unicompartmental knee arthroplasty(SBUKA) is an effective surgical treatment for bilateral medial knee osteoarthritis (MKOA). However, which intervention is more beneficial for bilateral MKOA patients remains unknown. Therefore, the aim of this study was to compare the effectiveness of these two strategies through early clinical outcomes, complication rates, and prosthetic survival.

METHODS

The clinical data of 60 patients with bilateral MKOA admitted to the Affiliated Hospital of Qingdao University from January 2018 to December 2022 were retrospectively analyzed, and they were divided into SBOWHTO group (n = 28) and SBUKA group (n = 32) according to different treatment methods. Clinical relevant indexes, Hospital for Special Surgery (HSS) score, Knee Society Knee (KSS) score, range of motion(ROM), postoperative complications and prosthetic survival rate were compared between the two groups.

RESULTS

Patients in the SBOWHTO group were followed up for 27 to 50 months, with an average of (37.18 ± 6.84) months. Patients in the SBUKA group were followed up for 24 to 59 months, with an average of (39.38 ± 9.74) months. There were no significant differences in postoperative KSS, HSS and ROM between SBOWHTO group and SBUKA group (p > 0.05). There was no significant difference in complication rate between the two groups (p = 0.721). There was no significant difference in prosthetic survival rate (p = 0.622) and prosthetic survival curve (χ2 = 0.546, p = 0.46) between the two groups.

CONCLUSIONS

This study compared early clinical outcomes, complication rates, and prosthesis retention rates after SBOWHTO and SBUKA, and found that the early clinical benefits of SBOWHTO and SBUKA were comparable in patients with bilateral MKOA.

High survivorship rate and good clinical outcomes after high tibial osteotomy in patients with radiological advanced medial knee osteoarthritis: a systematic review

INTRODUCTION

The role of valgus producing high tibial osteotomy (HTO) for the treatment of advanced knee osteoarthritis (OA) is still controversial. The aim of the current systematic review was to assess survivorship and patient-reported outcomes (PROMs) of high tibial osteotomy in patients with radiological advanced medial knee OA.

METHODS

A systematic search of PubMed, Cochrane and EMBASE database was performed in July 2023 in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines. Inclusion and exclusion criteria were applied to identify studies investigating the survivorship rate and PROMs of valgus-producing high tibial osteotomy in patients with advanced knee OA at x-ray assessment in the medial compartment at minimum-two-years follow up. Advanced radiological OA was defined as Kellgren Lawrence (K-L) ≥ 3 or Ahlbäch ≥ 2. Survivorship was defined as percentage of patients free of total knee arthroplasty (TKA) at follow-up. Clinical interpretation of provided PROMs were performed according to minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) target values reported in literature. Survivorship data and PROMs scores were extracted, and studies were stratified based on selected study features. The quality of included studies was assessed with modified Coleman score.

RESULTS

A total of 18 studies, totalling 1296 knees with a mean age between 46.9 and 67 years old, were included. Average survivorship was of 74.6% (range 60 - 98.1%) at 10-years follow up. The subjective scoring systems showed good results according to MCID and PASS, and postoperative improvements were partially maintained until final follow-up.

CONCLUSION

HTO is worth considering as treatment choice even in patients affected by radiological advanced medial knee osteoarthritis. Long term survivorship and good patient reported clinical outcomes could be expected in this population.

LEVEL OF EVIDENCE

IV; systematic review of level III-IV studies.

Effects of high tibial osteotomy compared with unicondylar knee arthroplasty on the surgical site wound infection and pain in patients with medial knee osteoarthritis

This study aims to comprehensively compare the effects of unicondylar knee arthroplasty (UKA) and high tibial osteotomy (HTO) on wound infection and pain in patients with medial knee osteoarthritis. A computerized search was conducted in Embase, PubMed, Google Scholar, China National Knowledge Infrastructure, Cochrane Library and Wanfang databases, from database inception to October 2023, for studies comparing UKA and HTO for medial knee osteoarthritis. Studies selection, data extraction and study quality evaluation were independently conducted by two researchers. Stata 17.0 software was employed for data analysis. Overall, 10 studies involving 870 patients with medial knee osteoarthritis were included. It was found that the UKA group had significantly lower wound visual analogue scale scores compared to the HTO group (SMD = -0.53, 95%CI: -0.87 to -0.20, p < 0.001). The incidence of wound infection in the UKA group was higher than in the HTO group (OR = 1.92, 95%CI: 0.65-5.69, p = 0.240), and the incidence of complications was lower (OR = 0.89, 95%CI: 0.52-1.54, p = 0.684), though these differences were not statistically significant. This study indicates that UKA is effective in alleviating postoperative wound pain in medial knee osteoarthritis. However, the rates of postoperative wound infection and complications are comparable to those of HTO. Clinicians should consider factors such as patient age and disease severity in making individualized treatment decisions.

Low central sensitisation inventory score is associated with better post-operative outcomes of osteotomy around the knee

PURPOSE

The purpose of this study was to investigate the potential association between central sensitisation inventory (CSI) scores and post-operative patient-reported outcomes (PROs) in patients underwent osteotomy around the knee (OAK), with a CSI cut-off score specific for knee osteoarthritis.

METHODS

CSI scores were collected from 173 patients who underwent OAK, along with their knee injury and osteoarthritis outcome score (KOOS) and pain numeric rating scale (NRS) scores. Patients were divided into high-CSI score group and low-CSI score group with a cut-off score of 17. Multivariate linear regression was performed to test the association between CSI scores and post-operative outcomes. Pre-surgery KOOS and NRS scores and the rate of attainment of minimal clinically important difference (MCID) of KOOS scores was analysed as secondary outcomes.

RESULTS

Low-CSI score group had significantly higher post-operative KOOS scores and lower pain NRS scores compared to the high-CSI score group (< p = 0.01) after adjusting for confounding factors. For pre-operative scores, only the KOOS-Symptom score was significantly different between the groups (64.7 ± 20.1 when CSI < 17 vs.55.1 ± 19.7 when CSI ≥ 17; p = 0.008). The low-CSI score group had significantly higher MCID achievement rates of KOOS-Pain, Symptom, and ADL than the high-CSI score group (86% vs. 68%; 74% vs. 55%; 86% vs. 67%, respectively; P < 0.05).

CONCLUSIONS

This study established an association between post-operative CSI scores ≥ 17 and poorer outcomes following OAK, highlighting the potential value of the CSI in identifying patients in need of more comprehensive peri-operative pain management.

LEVEL OF EVIDENCE

Level III. Retrospective comparative study.

Research on the Influence of the Allogeneic Bone Graft in Postoperative Recovery After MOWHTO: A Retrospective Study

Purpose

To compare the effects of an allogeneic bone graft and a non-filled bone graft on the rate of osteotomy gap union in medial opening wedge high tibial osteotomy (MOWHTO) with an opening width less than 10 mm.

Methods

A total of 65 patients undergoing MOWHTO between January 2018 and December 2020 were enrolled in this retrospective study. The patients were divided into two groups: the allograft group (MOWHTO with allogeneic bone grafting, 30 patients) and the non-filling group (MOWHTO without bone void fillers, 35 patients). The clinical outcomes, including the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC), Lysholm score, and post-operative complications, were compared. The radiographic evaluation included changes in hip-knee-ankle angle (HKA), medial proximal tibial angle (MPTA), femorotibial angle (FTA), and weight-bearing line ratio (WBLR) at pre-operation, at two-day post-operation, and the last follow-up. Radiographs were obtained at three, six and twelve months post-surgery, and at the time of the last follow-up to assess the fill area of the osteotomy gap. The union rate of the osteotomy gap was calculated and compared, and risk factors that may affect the rate of osteotomy gap union were also discussed.

Results

The rate of osteotomy gap union at 3 and 6 months after the operation in the allograft group was significantly higher compared with the non-filling group (all P<0.05), while no significant difference was found after the 1-year post-operative and at the last follow-up. Also, the WOMAC and Lysholm scores of the allograft group were significantly higher than those of the non-filling group (all P<0.05), and there was no significant difference between the two groups at the last follow-up.

Conclusion

Filling the gaps with the allograft bones may accelerate the union of osteotomy gap, improve clinical outcomes, and have important implications for patient rehabilitation in the early post-operative course. Bone grafting did not affect the final rate of osteotomy gap union and the clinical score of patients.

Unicompartmental knee arthroplasty is associated with lower pain levels but inferior range of motion, compared with high tibial osteotomy: a systematic overview of meta-analyses

Background

The purpose of this study was to overview the findings of reported meta-analyses on unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO).

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analysis 2020 (PRISMA 2020) guidelines were followed. Two independent reviewers conducted a literature search of PubMed, Embase, the Web of Science, and the Cochrane Database of Systematic Reviews for meta-analyses comparing UKA and HTO that were published prior to September 2021. Literature screening, data extraction, and article quality appraisal were performed according to the study protocol registered online at PROSPERO (CRD42021279152).

Results

A total of 10 meta-analyses were identified, and different studies reported different results. Five of the seven meta-analyses showed that the proportion of subjects with excellent or good functional results was higher for UKA than for HTO. All three meta-analyses showed that UKA was associated with lower pain levels, and all six of the studies that included an analysis of range of motion (ROM) reported that UKA was inferior to HTO. Four of the eight meta-analyses found that total complication rates were lower for UKA. Only 3 of the 10 meta-analyses found that UKA had lower revision rates. Moreover, in the subgroup analysis, the revision and complication rates of UKA were similar to those of opening-wedge HTO but much lower than those of closing-wedge HTO.

Conclusions

Compared to HTO, UKA was associated with lower pain levels but inferior postoperative ROM. The results were inconclusive regarding whether UKA yielded better knee function scores and lower revision or complication rates than HTO. Accurate identification of indications and appropriate patient selection are essential for treating individuals with OA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-03319-7.

Unicompartmental knee arthroplasty is superior to high tibial osteotomy for the treatment of medial unicompartmental osteoarthritis: A systematic review and meta-analysis

BACKGROUND

Unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) are widely used for the treatment of medial unicompartmental knee osteoarthritis (OA). However, the best approach remains controversial. This study aimed to present a systematic review and a meta-analysis to directly compare the clinical outcomes between HTO and UKA. We hypothesized that the clinical outcomes after UKA and HTO would be similar.

METHODS

Electronic databases (Web of Science, PubMed, Embase, CENTRAL, and Biosis Preview) were searched for related studies published before November 30, 2021. Retrospective and prospective studies that directly compared the postoperative outcomes between UKA and HTO were included. Odds ratio (ORs) and 95% confidence interval (CIs) for complications, revision to total knee arthroplasty (TKA), and weighted mean difference (MD) and 95% CIs in range of motion (ROM), pain, walking speed and function score were evaluated. Two reviewers independently assessed the quality of the studies. Subgroup and sensitivity analyses were performed to explore the heterogeneity.

RESULTS

Twenty-three retrospective and 6 prospective studies were included. A total of 3004 patients (3084 knees) were evaluated for comparison. Complications (OR, 4.88, 95% CI: 2.92-6.86) were significantly greater in the HTO group than in the UKA group. Postoperative function scores including Lysholm score (MD, -2.78, 95% CI: -5.37 to -0.18) and Hospital for Special Surgery (HSS) score (MD, -2.80, 95% CI: -5.39 to -0.20) were significantly lower in the HTO group than the UKA group. The postoperative ROM was similar between HTO and mobile-bearing UKA (MD, -3.78, 95% CI: -15.78 to 8.22). However, no significant differences were observed between the HTO and UKA group in terms of postoperative pain, walking speed, and revision to TKA.

CONCLUSIONS

UKA is superior to HTO in minimizing complications and enhancing postoperative function scores. Mobile-bearing UKA has a similar ROM compared with HTO. Both HTO and UKA provide satisfactory clinical outcomes in terms of walking speed, relieving pain, and revision to TKA. UKA appears to be more suitable for the elderly, and both mobile-bearing UKA and HTO are viable surgical options for younger active individuals.

A comparative study of 21,194 UKAs and 49,270 HTOs for the risk of unanticipated events in mid-age patients from the national claims data in South Korea

Background

Both high tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA) are well-established treatments for medial knee osteoarthritis (OA). However, over the past 20 years, results of comparisons of long-term survival rates and outcomes have remained controversial. Furthermore, in patients at the boundary age, from 50 to 70 years, considering age as a treatment indication, selecting a surgical method is difficult. Therefore, we aimed to investigate conversion rates to total knee arthroplasty (TKA) and perioperative adverse outcomes between the two surgical methods in mid-age patients.

Methods

We extracted data from the Korean National Health Insurance claims database. A total of 70,464 patients aged between 50 and 70 years, considered as mid-age patients were included in the final study population. We used a multivariable Cox proportional hazard regression model, adjusting for potential confounders such as age, sex, insurance type, region of residence, hospital type, comorbidities, and the Charlson comorbidity Index (CCI).

Results

Of the 70,464 patients, 21,194 were treated with UKA and 49,270 were treated with HTO. HTO showed a higher risk of revision than UKA at five, and 10 years and during the whole observation period. The incidence of deep vein thromboembolism, and surgical site infection was significantly higher in UKA than in HTO.

Conclusions

It is important to choose an appropriate surgical method considering that UKA has better results in terms of long-term survival rates but may have a higher incidence of various complications.

Patellofemoral Osteoarthritis Progresses After Medial Open-Wedge High Tibial Osteotomy: A Systematic Review

PURPOSE

To investigate the progression of patellofemoral (PF) osteoarthritis (OA) after medial open-wedge high tibial osteotomy (OWHTO) and whether PF OA progression has an influence on clinical outcomes.

METHODS

According to the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA), EMBASE, PubMed, and Cochrane Library were searched in June 2020 for English-language studies that presented data on PF OA or cartilage degeneration before and after OWHTO. Descriptive statistics are presented.

RESULTS

Twenty studies comprising 1,173 patients were included. The mean age was 57.1 years (range 18-84) with 826 (70.4%) female. The mean follow-up was 27.1 months (range 7-144). Ten studies reported the trochlear International Cartilage Research Society (ICRS) scores, with each of these studies reporting a greater proportion of patients with grades 2-4 OA postoperatively compared with preoperatively (relative risk = 1.19-2.76, I² = 1.9%). Similarly, 7 studies reported patellar ICRS scores and found a greater proportion with grades 2-4 OA postoperatively (relative risk = 1.08-2.44, I² = 0%). Four studies assessed PF Kellgren-Lawrence grade, each of which reported a greater proportion of patients with grades 2-4 OA postoperatively (relative risk = 1.25-21.0, I² = 31%). The PF OA assessments were heterogenous, and studies using classifications except the ICRS score or Kellgren-Lawrence grade were not included in statistical analysis. Fifteen studies assessed patellar height; 10 studies reported significant decrease in patellar height after OWHTO. Only 3 studies reported clinical outcomes for patients with and without PF OA progression. Outcome reporting was variable across these studies, and a relationship between PF OA progression and clinical outcome could not be definitively determined.

CONCLUSIONS

Patients appear to have progression of PF OA after medial OWHTO. However, there are currently insufficient studies with inconsistent measurements of outcomes to make meaningful conclusions regarding the impact of PF OA on clinical outcomes.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III-IV studies.

Evaluation of the "Minimal Clinically Important Difference" (MCID) of the KOOS, KSS and SF-12 scores after open-wedge high tibial osteotomy

PURPOSE

Defining a Minimal Clinically Important Difference (MCID) value for Patient-Reported Outcome Measures (PROMs) is crucial for determining the effectiveness of a procedure and calculating the sample size for trial planning. The purpose of this study was to determine the MCID of several PROMs (Knee injury and Osteoarthritis Outcome Score (KOOS), Knee Society Score (KSS) and the SF-12) in patients who underwent medial opening-wedge High-Tibial Osteotomy (owHTO) with Patient-Specific Cutting Guides (PSCGs), using anchor-based methods.

METHODS

Patients undergoing isolated medial owHTO with PSCGs between January 2013 and January 2017 were enrolled in this single-center, prospective, observational study. Three outcome scores were collected pre-operatively and at the 2 years follow-up evaluation: KOOS, KSS and SF-12. The MCIDs were calculated using anchor-based method: at 2 years postoperatively: "Compared with before surgery, how would you rate operated joint now?" The responses were recorded using a five-point scale. Patients who answered "about the same" or "somewhat worse" were classified into the no change group, while those who answered "somewhat better" were classified into the minimal change group. A receiver operating characteristic (ROC) curve was used to define the cutoff point that best discriminated between the minimal change and no change groups for each PROMs RESULTS: 196 patients were included, 75 (somewhat better) and 24 patients (about the same and somewhat worse) were, respectively, assigned to the "no change" and "minimal change" groups. There was no significant difference between the two groups in terms of baseline characteristics and postoperative complications. At 24 months follow-up all the PROMs (KOOS, KSS and SF-12) were significantly better for the "minimal change" group compared to the "no change" group. MCID was 15.4 for KOOS pain, 15.1 for KOOS symptoms, 17 for KOOS ADL, 11.2 for KOOS sports/recreation, 16.5 for KOOS QQL, 3 for KSS symptoms, 5.6 for KSS activity, 7.2 for SF-12 physical component and 6.3 for PCS mental component.

CONCLUSION

This study determined the MCIDs of common used PROMs in patients undergoing owHTO.

LEVEL OF EVIDENCE

Prospective Cohort Study, Level II.

Unicompartmental knee replacement and high tibial osteotomy for medial unicompartmental knee osteoarthritis: A comparative study protocol

BACKGROUND

Many clinical studies have been published in the literature to compare the outcomes of unicompartmental knee replacement (UKR) and high tibial osteotomy (HTO), but reached different conclusions. Therefore, the relative merits and demerits of these 2 procedures remain under debate. The purpose of the present protocol was to design a retrospective comparative study to further investigate the clinical effectiveness of HTO compared to UKR in the medial unicompartmental osteoarthritis of knee patients.

METHODS

This is an observational retrospective research, which prospectively collected the data from several surgeons in our center and utilized the above 2 methods to treat the unicompartmental osteoarthritis of knee. In our single hospital, we reviewed unicompartmental knee osteoarthritis patients treated using UKR or HTO from June 2016 to February 2018. For the HTO, its criteria included:For the UKR, its inclusion criteria containedIn our cohorts, the clinical investigations of the knee were composed of the objective parameters, which were recorded and then documented through utilizing the Function Score and Orthopedic American Knee Society Knee Score. The extra clinical findings evaluated involved operative time, postoperative requirements of blood transfusion, possible postoperative complications, as well as the range of motion.

CONCLUSION AND DISCUSSION

The results of this study will provide clinical evidence on appropriate surgical treatment for patients with medial unicompartmental knee osteoarthritis.

TRIAL REGISTRATION

This study protocol was registered in Research Registry (researchregistry6152).

Opening wedge high tibial osteotomy allows better outcomes than unicompartmental knee arthroplasty in patients expecting to return to impact sports

PURPOSE

Prior studies have compared unicompartmental knee arthroplasty (UKA) with high tibial osteotomy (HTO) suggesting that both procedures had good functional outcomes. But none had established the superiority of one of the two procedures for patients with high expectation including return to impact sport. The aim of this study was to compare functional outcomes and ability to return to impact sport of active patients defined with a pre-arthritis University of California and Los Angeles activity (UCLA) score > 8, after UKA or HTO procedures.

METHODS

A retrospective review of patients with a pre-arthritis UCLA score > 8 operated between January 2014 and September 2017 has identified 91 patients with open-wedge HTO and 117 patients with UKA. A matching process based on age (± 3 years) and gender allowed to include 50 patients in each group for comparative analysis. Patient reported outcomes included Knee Osteoarthritis Outcomes Score (KOOS), UCLA Score, Knee Society Score (KSS) and time to return to sport or previous professional activities at 3, 6, 12 and 24 months following surgery.

RESULTS

Mean time to return to sport activities or previous professional activities were significantly lower for the HTO group than for UKA group [respectively, 4.9 ± 2.2 months for HTO group vs 5.8 ± 6.2 months for UKA group (p = 0.006) and 3 ± 3 months for HTO group vs 4 ± 3 months for UKA group (p = 0.006)]. At 24-month follow-up, UCLA score, KOOS Sports Sub-score and KSS activity score were significantly higher for HTO group than for UKA group (Δ: 2 CI 95% (1.3-2.5 points) p < 0.0001, (Δ: 10.9 CI 95% (2.9-18.9 points) p = 0.04 and Δ: 7.8 CI 95% (2.4-13.4 points) p = 0.006, respectively) and 31 patients (62%) were practicing impact sport in the HTO group versus 14 (28%) in the UKA group (odd-ratio 4.2 CI 95% (1.8-9.7) p < 0.0001).

CONCLUSION

HTO offers statistically significant quicker return to sport activities and previous professional activities with a higher rate of patients able to practice impact activity (62% for HTO vs 28% for UKA) and better sports related functional scores at two years after surgery compared to UKA.

LEVEL OF EVIDENCE

III retrospective case-control study.

The risk factors for early conversion to total knee arthroplasty after high tibial osteotomy

The primary aim was to identify potential risk factors for early conversion to total knee arthroplasty (TKA) in patients with high tibial osteotomy (HTO) surgery. A retrospective study was conducted and 240 patients received HTO surgery between January 2008 and January 2014 were included in this study. The associations between different clinical factors and HTO survivorship were analyzed. A logistic regression analysis was performed to detect independent risk factors for HTO survivorship. The cut-off value, sensitivity and specificity of these independent factors were calculated by receiver operating characteristic (ROC) curve. In this study, thirty-five (14.6%) patients were early conversion to TKA within a 5-year follow-up. These results indicated that age, body mass index (BMI), preoperative Kellgren-Lawrence (K-L) grade and preoperative visual analogue scale (VAS) score were potential risk factors for HTO survivorship. The cut-off values of those factors were 60 years, 25.35 kg/m2, 2 and 5, respectively. The combination of age, BMI, preoperative K-L grade and preoperative VAS score has the highest predictive value for HTO survivorship (AUC = 0.896, P < 0.001). Based on the present study, the five-year HTO survivorship for the treatment of medial compartment osteoarthritis of the knee was approximately 85.4%. We identified age >60 years, BMI >25.35 kg/m2, preoperative K-L grade >2 and preoperative VAS score >5 as independent risk factors for early conversion to TKA in patients with HTO surgery, and those factors combined had the highest predictive value for predicting early conversion to TKA.

Long-term outcomes of unicompartmental knee arthroplasty in patients requiring high flexion: an average 10-year follow-up study

INTRODUCTION

To evaluate the long-term survival of unicompartmental knee arthroplasty (UKA) in the Asian population and assess differences in clinical outcomes between mobile- and fixed-bearing UKA.

MATERIALS AND METHODS

Among 111 cases of UKA that were performed by 1 surgeon from January 2002 to December 2009, we retrospectively reviewed 96 cases (36 mobile-bearing, 62 fixed-bearing) for this study. We examined cause of revision or failure, type of reoperation/revision, and duration from the surgery date to the revision upon reviewing the medical record. Survival analysis was conducted using the Kaplan-Meier method. Functional outcomes were evaluated based on range of motion and patient-reported outcome (PRO) measures (Knee Injury and Osteoarthritis Outcome Score) for cases with at least 8 years of follow-up (average, 10.2 years).

RESULTS

Overall, the 10-year survival was 88% [95% confidence interval (CI) 0.81-0.95], and the estimated mean survival time was 13.4 years (95% CI 12.5-14.2). In a comparison of survival between the mobile- and fixed-bearing groups, the former had a 10-year survival of 85% (95% CI, 0.72-0.97) and an estimated mean survival time of 13.5 years (95% CI 12.2-14.7) and the latter had a 10-year survival of 90% (95% CI 0.82-0.99) and an estimated mean survival time of 13.4 years (95% CI 12.3-14.4). Thus, there was no significant difference in survival between the two groups (log-rank test, p = 0.718). In addition, no significant difference in functional outcomes was observed between the two groups (p > 0.05 for all).

CONCLUSIONS

UKA performed in the Asian population showed a relatively good functional outcome and survival rate at an average 10-year follow-up. No difference in survival and PROs was observed according to the bearing type. Although the present study demonstrated a good survival rate, similar to that in other Western studies, further studies investigating the impact of the Asian lifestyle on the long-term survival of UKA is necessary.

The patient results and satisfaction of knee arthroplasty in a validated grading system

INTRODUCTION

The validated Knee Osteoarthritis Grading System (KOGS) was implemented and clinical results were compared with patient satisfaction data and implant survivorship in a multi-centre study with surgeons familiar with unicompartmental knee arthroplasty (UKA), patellofemoral arthroplasty (PFA) and total knee arthroplasty (TKA). This is also the first study to evaluate the prevalence of UKA and TKA in consecutive osteoarthritis (OA) knee arthroplasties assessed by this system..

METHOD

A consecutive cohort of knees was gathered at three different institutions as categorized by KOGS and surgically treated with the recommended implant unless clinical reasons or patient preference precluded such an option. One thousand one hundred seventy-seven consecutive knees were evaluated including 311 TKA (26%), 695 medial UKA (59%), 154 lateral UKA (13%) and 17 PFA (2%) and the results of the categories evaluated with the Oxford Knee Score (OKS) and the complications reflected in the different categories.

RESULTS

The failure rate of the UKA (3.5%) or TKA (1.6%) is not higher than accepted results in the literature and the difference in complications is negligible between the UKA (72%) and TKA (26%) cohorts. Revision of a UKA to a TKA as an endpoint was 0.58% with ipsilateral progression at 0.8% over a period of five to 84 months (mean follow-up of 36 months) despite the 'excessive' proportion of UKA in this cohort. The Oxford Score improvement is significant in TKA and UKA and contributes to the acceptable outcomes (The OKS for TKA improved from 20 pre-operatively to 36 post-operatively and the UKA improved from 22 pre-operatively to 39 post-operatively).

CONCLUSION

KOGS achieves acceptable early survival and functional results when implemented and is a suitable tool for identifying the preferred implant as was validated.

Safety of simultaneous versus staged bilateral opening-wedge high tibial osteotomy with locked plate and immediate weight bearing

PURPOSE

With advances in technology and particularly locked screws, patients with high tibial osteotomy (HTO) are frequently allowed full weight bearing for a  unilateral procedure. We are aware of no reports comparing the safety of a simultaneous bilateral HTO with staged bilateral HTO. The purpose of this study was to retrospectively compare these two strategies.

MATERIAL AND METHODS

Ninety patients were treated with bilateral HTO surgery for osteoarthritis from 2009 to 2013; they had opening-wedge HTO and fixed with the same plate fixation and locked screws. A comparison of the outcomes after simultaneous bilateral HTO (35 patients) and after sequential staged bilateral HTO (55 patients) was performed. We considered four measures of medical safety: hypotension, serious intra-operative adverse event, heterologous blood transfusion, and thrombophlebitis. We considered also four measures of orthopaedic safety: infection, patient's inability to walk full weight bearing, changes in correction, and nonunion.

RESULTS

For the same duration of operation, the duration of anaesthesia and the time in the operating room were 35% longer for patients having a staged bilateral HTO. Blood loss was higher in patients undergoing simultaneous bilateral HTO compared with those who underwent a staged bilateral HTO. For patients undergoing simultaneous bilateral HTO, thrombophlebitis frequency and length of anticoagulation were lower than the sum of each event in the staged bilateral HTO. The patients with simultaneous bilateral HTO had a longer total period of time for crutches than patients with staged bilateral HTO. Patients in the simultaneous bilateral cohort did not develop an infection within one year as patients in the planned-stage cohort. The simultaneous bilateral cohort had a lower rate of delayed union than the planned-stage cohort did.

CONCLUSION

On the basis of this analysis, simultaneous bilateral HTO is a reasonable treatment option. Individuals who undergo staged bilateral HTO face the risk of complications twice, in addition to two hospitalizations. Patients who undergo simultaneous bilateral HTO have a higher risk of blood transfusion.

The forgotten joint score in total and unicompartmental knee arthroplasty: a prospective cohort study

PURPOSE

The purpose of this study was to assess whether unicompartmental knee arthroplasty (UKA) results in better patient-reported and clinical outcome than total knee arthroplasty (TKA). The study hypothesis was UKA yields better patient-reported and clinical outcomes than TKA.

METHODS

Our prospective cohort study compared patients who underwent medial UKA or TKA from February 2014 through June 2015. Forgotten Joint Score (FJS), the short form of the Knee Injury and Osteoarthritis Outcome Score (KOOS PS), EuroQOL Five Dimensions Questionnaire (EQ-5D), and the Knee Society Score (KSS) were completed at two weeks, six weeks, three months, six months, and one year post-operatively. The KOOS PS, EQ-5D, and the KSS were also documented pre-operatively.

RESULTS

Fifty-seven patients (57 knees) were allocated to the UKA group and 62 patients (62 knees) to the TKA group. At baseline, no statistically significant differences were observed between groups regarding patient demographics and pre-operative scores. Except for FJS at 2 weeks (p = 0.326), all postoperative scores revealed significant differences as early as two weeks and up to 12 months (p < 0.05).

CONCLUSIONS

Our findings suggest UKA patients are less aware of their joint replacements than TKA patients for medial osteoarthritis of the knee. UKA conserves more soft tissue and bone than TKA, which may be the reason for the differences observed.

Long-term survival is similar between closed-wedge high tibial osteotomy and unicompartmental knee arthroplasty in patients with similar demographics

PURPOSE

Long-term clinical and radiographic results and survival rates were compared between closed-wedge high tibial osteotomy (HTOs) and fixed-bearing unicompartmental knee arthroplasty (UKA) in patients with similar demographics.

METHODS

Sixty HTOs and 50 UKAs completed between 1992 and 1998 were retrospectively reviewed. There were no significant differences in pre-operative demographics. The mean follow-up period was 10.7 ± 5.7 years for HTO and 12.0 ± 7.1 years for UKA (n.s.). The Knee Society knee and function scores, WOMAC, and range of motion (ROM) were investigated. The mechanical axis and femorotibial angle were evaluated. Kaplan-Meier survival analysis was performed (failure: revision to TKA) and the failure modes were investigated.

RESULTS

Most of the clinical and radiographic results were not different at the last follow-up, except ROM; ROM was 135.3° ± 12.3° in HTO and 126.8° ± 13.3° in UKA (p = 0.005). The 5-, 10-, 15-, and 20-year survival rates were 100%, 91.0%, 63.4%, and 48.3% for closed-wedge HTO, respectively, and 90.5%, 87.1%, 70.8%, and 66.4% for UKA (n.s.). The survival rate was higher than that for UKA until 12 years post-operatively but was higher in UKAs thereafter, following a remarkable decrease in HTO. The most common failure mode was degenerative osteoarthritic progression of medial compartment in HTO and femoral component loosening in UKA.

CONCLUSIONS

Long-term survival did not differ significantly between closed-wedge HTO and fixed-bearing UKA in patients with similar pre-operative demographics and knee conditions. The difference in post-operative ROM and failure mode should be considered when selecting a procedure.

LEVEL OF EVIDENCE

III.