Outcome Of Unicompartmental Knee Replacement Research Articles

Unicompartmental vs. total knee replacement in patients with failed high tibial osteotomy.

The influence of a previous high tibial osteotomy (HTO) on the outcome and survival of a knee arthroplasty is a debated issue. The purpose of this study is to compare subjective, radiographic, and functional outcomes of unicompartmental knee replacement (UKR) and total knee replacement (TKR) after failed open wedge HTO. 26 post-HTO UKRs (group A) with an average follow-up of 7.8years (range 2-13), and 33 post-HTO TKRs (group B) with an average follow-up of 11.2years (range 4-16) operated between 2001 and 2017, were retrospectively reviewed. Assessment included Knee Society Score (KSS), University of California at Los Angeles Activity Score (UCLA), and Western Ontario and McMaster University Osteoarthritis Index (WOMAC). Standard knee X-rays, and long-standing X-rays were performed pre-operatively and at follow-up to evaluate prosthesis survival, coronal alignment, and patellar height. Improvements regarding KSS, UCLA and WOMAC scores were noted at follow-up in both groups compared to pre-operatory status (p < 0.001). No statistically significant differences in clinical and functional postoperative scores were reported between groups (p = n.s.) at follow-up. Group B presented a more neutral mean mechanical axis of 0.5° compared to 2.7° in Group A (p < 0.001). Performing UKR after previous failed HTO is a safe and effective procedure which leads to clinical, radiological and functional outcomes comparable to TKR after HTO.

Better immediate and early postoperative outcomes of unicompartmental knee replacement comparing with total knee replacement: A matched cohort of patients with medial knee osteoarthritis

Introduction: This study compared the immediate and early postoperative outcomes of medial compartment knee osteoarthritis patients receiving unicompartmental knee replacement (UKR) with a matched cohort of total knee replacement (TKR). Methods: 26 UKR patients were matched with 26 TKR patients based on age, body mass index, pre-operative radiographic severity, range of motion (ROM), Knee Society score (KSS) and Feller patella score. Immediate postoperative outcomes were reflected by postoperative pain, blood loss, length of stay and the number of physiotherapy sessions attended. Early postoperative outcomes (ROM and KSS) were measured at 3 months and 1 year post-operatively. Results: UKR patients had less hemoglobin drop (UKR: 1.2 g/dL, TKR: 1.6 g/dL, p = 0.04), shorter length of stay (UKR: 4.3 days, TKR: 6.0 days, p &lt; 0.001) and required less physiotherapy sessions for recovery (UKR: 6.9 sessions, TKR: 9.3 sessions, p &lt; 0.05). There were no statistically significant differences in early post-operative pain score and postoperative analgesia use ( p &gt; 0.05) between the two groups. Patients receiving UKR had significantly higher post-operative KSS (UKR: 155.9, TKR: 142.4, p = 0.005) and ROM (UKR: 115.8o, TKR: 98.8o, p &lt; 0.001) at 3 months. The KSS and ROM of UKR group at 3 months was better than TKR group at 1-year follow-up. Conclusion: In patients with medial knee osteoarthritis, UKR showed less postoperative analgesic use and blood loss, shorter length of stay, shorter course of rehabilitation and faster recovery with better early KSS and ROM than TKR. Follow up is necessary for comparison in long term outcome and survivorship between the two groups.

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:1.patients ≤65 years of age with separated medial compartment osteoarthritis of knee joint, and the patients’ age is equal to or less than 65 years old,2.patients without the ligament instability.For the UKR, its inclusion criteria contained1.the osteoarthritis of knee joint, including the isolated medial compartments of knee, but no degenerative changes in lateral compartment,2.rectifiable varus deformity, and3.the patients with an intact anterior cruciate ligament.In 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).

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

PurposePosterior 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.MethodsA 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.ResultsNine 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.ConclusionThe 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 evidenceIV.

Age and Body Mass Index Has No Adverse Effect on Clinical Outcome of Unicompartmental Knee Replacement - Midterm Followup Study.

Introduction:Unicompartmental knee replacement (UKR) is well-established procedure for the anteromedial compartment of knee arthritis with intact anterior cruciate ligament. The significance of age and body mass index (BMI) is not clear in the outcomes of UKR. Our hypothesis was that age and BMI does not affect the clinical and functional outcome following fixed bearing UKR.Materials and Methods:The study cohort of 148 was selected after stringent inclusion criteria and average followup was 5.6 years (range 2–10 years). The fixed bearing Miller Galante UKR procedure was carried out on all patients.Results:In the study cohort of 175, the average age of the cohort was 61.7 years. The sample size aged ≤55 years and aged ≥55 years was 38 and 137, respectively. The mean BMI of the cohort was 29.2 kg/m2 (range: 21–38 kg/m2). The sample size of BMI ≤30 kg/m2 and BMI ≥30 kg/m2 was 117 and 58, respectively. In the cohort group, BMI ≤30 kg/m2 and BMI ≥30 kg/m2, there was no statistically significant difference in the Knee Society Score clinical scores, functional scores, and knee range of motion scores, (P > 0.05). This study infers no statistically significant difference in the clinical and functional outcome between age group ≤55 years and age ≥55 years, (P > 0.05). The failure rates of the group of BMI ≤30 kg/m2 and BMI ≥30 kg/m2 were 4.27% (5 knees) 3.44% (2 knees), respectively. The failure rates in the age group ≤55 years and group ≥55 years were 2 knees (3.44%) and 5 knees (4.27%), respectively.Conclusion:This study confirms that age and BMI does not influence the functional outcome and clinical outcome following fixed bearing UKR.

Minimally invasive unicompartmental knee replacement: Midterm clinical outcome.

ObjectiveThe purpose of this study was to explore the midterm clinical outcomes of unicompartmental knee replacement (UKR) for medial knee arthropathy through a minimally invasive approach (MIA).MethodsFrom January 2006 to June 2010, 442 consecutive patients (485 knees) were included in the study. All patients underwent MIA-UKR with the mobile bearing Oxford phrase III prosthesis. The incision was made starting 1 cm medial to the medial pole of the patella and extending distally to the tibial tubercle. Radiographic evaluations include femorotibial angle (FTA) from coronal x-rays and rectified varus deformity angle, while clinical evaluations included Knee Society Score (KSS, clinical score and function score), the Western Ontario and McMaster Universities Arthritis Index (WOMAC) osteoarthritis index and visual analog scale (VAS) for pain. Patients followed-up at 1, 3, 6, 12 months after surgery and each year thereafter.ResultsFour hundreds and two patients completed the entire follow-up, 40 patients (45 knees) were lost to follow-up. The average follow-up time was 73.0 ± 1.9 months. The mean length of the incisions was 5.0 ± 0.2 cm. The average FTA decreased from 183.6° ± 5.1° preoperatively to 174.3° ± 4.2° postoperatively, and the mean rectified varus deformity angle was 9.3° ± 1.2°. The KSS clinical score improved from 42.4 ± 2.9 to 92.9 ± 3.8, and the function score improved from 53.5 ± 3.8 to 93.5 ± 4.0. The WOMAC score improved from 47.5 ± 3.1 preoperatively to 12.3 ± 1.5 at the last evaluation. The VAS dropped from 7.8 ± 1.9 preoperatively to 1.6 ± 0.2 postoperatively. All clinical evaluations (KSS, WOMAC, VAS) were significantly different (p < 0.05) from pre and post-operative evaluations. The survival rate was 99.1% at 73 months, and the revision rate was 0.9%.ConclusionThe midterm clinical outcomes of MIA-UKR are satisfactory in a Chinese patient population, which is a good surgical option for patients with medial arthropathy of the knee. However, longer-term follow-up studies should be performed in these patients.

The influence of patellofemoral degenerative changes on the outcome of unicompartmental knee replacement (UKA)

The influence of patellofemoral degenerative changes on the outcome of unicompartmental knee replacement (UKA)

Obesity has no adverse effect on the outcome of unicompartmental knee replacement at a minimum follow-up of seven years

The significance of weight in the indications for unicompartmental knee replacement (UKR) is unclear. Our hypothesis was that weight does not affect the long-term rate of survival of UKRs. We undertook a retrospective study of 212 UKRs at a mean follow-up of 12 years (7 to 22). The patients were distributed according to body mass index (BMI; < vs ≥ 30 kg/m(2)) and weight (< vs ≥ 82 kg). Kaplan-Meier survivorship analysis was performed and ten-year survival rates were compared between the sub-groups. Multimodal regression analysis determined the impact of the various theoretical contraindications on the long-term rate of survival of UKR. The ten-year rates of survival were similar in the two weight subgroups (≥ 82 kg: 93.5% (95% confidence interval (CI) 66.5 to 96.3); < 82 kg: 92.5% (95% CI 82.5 to 94.1)) and also in the two BMI subgroups (≥ 30 kg/m(2): 92% (95% CI 82.5 to 95.3); < 30 kg/m(2): 94% (95% CI 78.4 to 95.9)). Multimodal regression analysis revealed that weight plays a part in reducing the risk of revision with a relative risk of 0.387, although this did not reach statistical significance (p = 0.662). The results relating weight and BMI to the clinical outcome were not statistically significant. Thus, this study confirms that weight does not influence the long-term rate of survival of UKR.

Does body mass index affect the outcome of unicompartmental knee replacement?

BackgroundObesity is considered to be a contraindication for unicompartmental knee replacement (UKR). The aim was to study the impact of BMI on failure rate and clinical outcome of the Oxford mobile bearing UKR. MethodTwo thousand four hundred and thirty-eight medial Oxford UKRs were studied prospectively and divided into groups: BMI<25 (n=378), BMI 25 to <30 (n=856), BMI 30 to <35 (n=712), BMI 35 to <40 (n=286), and BMI 40 to <45 (n=126) and BMI≥45 (n=80). ResultsThere was no significant difference in survival rate between groups. At a mean follow-up of 5years (range 1–12years) there was no significant difference in the Objective American Knee Society Score between groups. There was a significant (p<0.01) trend with the Oxford Knee Score (OKS) and Functional American Knee Society Scores decreasing with increasing BMI. As there was an opposite trend (p<0.01) in pre-operative OKS, the change in OKS increased with increasing BMI (p=0.048). The mean age at surgery was significantly (p<0.01) lower in patients with higher BMI. ConclusionsIncreasing BMI was not associated with an increasing failure rate. It was also not associated with a decreasing benefit from the operation. Therefore, a high BMI should not be considered a contra-indication to mobile bearing UKR. Level of evidenceIV

The effect of leg alignment on the outcome of unicompartmental knee replacement

Varus malalignment after total knee replacement is associated with a poor outcome. Our aim was to determine whether the same was true for medial unicompartmental knee replacement (UKR). The anatomical leg alignment was measured prospectively using a long-arm goniometer in 160 knees with an Oxford UKR. Patients were then grouped according to their mechanical leg alignment as neutral (5 degrees to 10 degrees of valgus), mild varus (0 degrees to 4 degrees of valgus) and marked varus (> 0 degrees of varus). The groups were compared at five years in terms of absolute and change in the Oxford Knee score, American Knee Society score and the incidence of radiolucent lines. Post-operatively, 29 (18%) patients had mild varus and 13 (8%) had marked varus. The mean American Knee Society score worsened significantly (p < 0.001) with increasing varus. This difference disappeared if a three-point deduction for each degree of malalignment was removed. No other score deteriorated with increasing varus, and the frequency of occurrence of radiolucent lines was the same in each group. We therefore conclude that after Oxford UKR, about 25% of patients have varus alignment, but that this does not compromise their clinical or radiological outcome. Following UKR the deductions for malalignment in the American Knee Society score are not justified.

The effect of alignment of the knee on the outcome of unicompartmental knee replacement.

Many authors have recommended undercorrection of the deformity when carrying out unicompartmental knee arthroplasty (UKA). The isolated effect of alignment of the knee on the outcome of UKA has, however, received little attention. We reviewed 185 UKAs at a minimum of five years after surgery. They had been carried out by a single surgeon using metal-backed tibial components in the management of arthritis of the medial compartment. We measured the tibiofemoral angle (TFA) before and at four months after operation and at the most recent assessment. The amount of correction of the TFA and any subsequent loss were recorded. While adjusting for the effects of age, weight and gender of the patients and the type and thickness of the implants, the mean correction was significantly less for those with a Marmor rating of failure (6.8 degrees) than for those rated excellent (9.2 degrees). The mean correction was also significantly less for patients with a Marmor rating of failure (6.8 degrees) than for those rated poor (11.1 degrees). The mean correction for the UKAs which were revised (6.6 degrees) was significantly less than for those not revised (9.1 degrees). Additionally, revised UKAs had a significantly higher percentage (63%) of thinner tibial implants (<8 mm) than the surviving UKAs (27%). These findings suggest that undercorrection of the TFA in UKA of the medial compartment should be avoided, particularly if a thin tibial polyethylene insert is used.

The effect of alignment of the knee on the outcome of unicompartmental knee replacement

Many authors have recommended undercorrection of the deformity when carrying out unicompartmental knee arthroplasty (UKA). The isolated effect of alignment of the knee on the outcome of UKA has, however, received little attention. We reviewed 185 UKAs at a minimum of five years after surgery. They had been carried out by a single surgeon using metal-backed tibial components in the management of arthritis of the medial compartment. We measured the tibiofemoral angle (TFA) before and at four months after operation and at the most recent assessment. The amount of correction of the TFA and any subsequent loss were recorded. While adjusting for the effects of age, weight and gender of the patients and the type and thickness of the implants, the mean correction was significantly less for those with a Marmor rating of failure (6.8°) than for those rated excellent (9.2°). The mean correction was also significantly less for patients with a Marmor rating of failure (6.8°) than for those rated poor (11.1°). The mean correction for the UKAs which were revised (6.6°) was significantly less than for those not revised (9.1°). Additionally, revised UKAs had a significantly higher percentage (63%) of thinner tibial implants (&lt; 8 mm) than the surviving UKAs (27%). These findings suggest that undercorrection of the TFA in UKA of the medial compartment should be avoided, particularly if a thin tibial polyethylene insert is used.