American Knee Society Function Scores Research Articles

The effects on joint functions of biplanar distal tubercle open-wedge high tibial osteotomy: A prospective study.

Distal tubercle biplanar open-wedge high tibial osteotomy (DT-BOWHTO) is a method frequently applied in the treatment of knee joint medial osteoarthritis. The aim of this study was to evaluate the radiological, clinical, and functional results of patients at 5 years after DT-BOWHTO surgery. The study included a total of 41 patients who underwent DT-BOWHTO, comprising 19 (46.3%) males and 22 (53.7%) females with a mean age of 55.54 ± 4.17 (45-63) years and mean follow-up of 66.76 ± 6.29 (60-81) months. Statistical comparisons were made of the preoperative and postoperative body mass index (BMI), modified Insall-Salvati index, Blackburn-Peel index, Kelgren-Lawrence classification (KLC), tibial slope angle, American Knee Society Functional Score (AKSFS), Clinical American Knee Society Score (CAKSS), visual analog scale (VAS) pain score, Tegner Functional Activity Score (TFAS), total corrected angular measurements (TCA), and the tibio-femoral varus angle. Compared to the preoperative values, no statistically significant difference was determined in the postoperative modified Insall-Salvati index, Blackburn-Peel index, and tibial slope angle values (P > .05), and a statistically significant difference was determined in the BMI, AKSFS, CAKSS, VAS, KLC, tibio-femoral varus angle, and TFAS values (P ≤ .001). When the preoperative and postoperative BMI values were compared in 3 groups of normal, overweight, and obese, there was found to be a statistically significant difference (P = .014). No significant correlation was determined between the BMI values and the VAS and KLC values (P > .05). No significant correlation was determined between the total corrected angular and the preoperative and postoperative pain, and clinical and functional knee scores (VAS, AKSFS, CAKSS, TFAS) (P > .05). DT-BOWHTO was seen to provide extremely good 5-year results in the knee clinical findings, pain severity, and functional results. As the patella height and tibial slope angle were not changed, this did not cause the development of osteoarthritis in the patellofemoral and tibiofemoral joints. Grafting and fixation of the tibial tubercle with additional screws in the application of DT-BOWHTO were not seen to make any additional contribution to the healing of the osteotomy line. There was no relationship between increased BMI, reduced pain, and increase in knee functions in patients who underwent DT-BOWHTO.

The impact of preoperative MRI-detected lateral meniscal intra-substance signal abnormalities on mid-term functional outcomes following mobile-bearing unicompartmental knee arthroplasty.

There is a dilemma as to whether the presence of degenerative changes of lateral meniscus is a contraindication to medial unicompartmental knee arthroplasty (UKA). Therefore, the purpose of this study is to assess the influence of preoperative MRI-detected lateral meniscal intra-substance signal abnormalities on mid-term functional outcomes following mobile-bearing UKA. We performed a retrospective review of the record on a consecutive series of patients who have undergone mobile-bearing medial UKA from September 2020 to June 2023. The mean duration of follow-up was 2.34 years. All records were collected from case system. MRI assessment of lateral meniscus was performed with the use of the Stoller's classification system. Patients were categorized into two groups (grade 0 and ≥ grade 1). Patient-reported outcomes were assessed with the use of the American Knee Society functional Score (AKSS-F), American Knee Society Objective Score (AKSS-O), and Oxford Knee Score (OKS) preoperatively and at latest follow-up. Furthermore, range of motion (ROM) and hip-knee-ankle angle (HKA) were measured in preoperative and postoperative periods. A total of 92 patients (101 knees) were included in our study. No differences in AKSS-F, AKSS-O, OKS, HKA, or ROM were found between those who showed normal or abnormal signal change of lateral meniscus preoperatively (P < 0.05). Furthermore, there were also no significant differences between two groups concerning AKSS-F, AKSS-O, OKS, HKA, or ROM at latest postoperative follow-up (P < 0.05). Age and duration of disease were independent predictors of low postoperative AKSS-F and AKSS-O (P < 0.05). Nevertheless, ROM was an independent predictor of high postoperative AKKS-O (P < 0.05). Age and female were independent predictors of high postoperative OKS (P < 0.05). The presence of preoperative MRI-detected lateral meniscal degenerative changes did not affect mid-term functional outcomes in patients who underwent mobile-bearing medial UKA. On the basis of the results of the current study, we believe that the presence of degenerative changes of lateral meniscus is acceptable in mobile-bearing medial UKA.

Clinical Outcomes of Unicompartmental Knee Arthroplasty in Patients with Full-versus Partial-Thickness Cartilage Loss: A Systematic Review and Meta-Analysis.

The objective of the study was to compare postoperative patient-reported outcomes and reoperation rates following unicompartmental knee arthroplasty (UKA) between patients with full-thickness cartilage loss (FTCL) and partial-thickness cartilage loss (PTCL). Multiple databases, including PubMed, Embase, Cochrane Library, and CNKI, were searched until October 2019 for studies comparing the Oxford Knee Score (OKS), American Knee Society (AKS) score, and reoperation rates between patients with FTCL and PTCL following UKA. Data analysis was performed using Review Manager software. A total of 613 UKA cases from 5 retrospective cohort studies were included. The mean difference in postoperative OKSs was significantly higher by 2.92 in FTCL group than in PTCL group (95% confidence interval [CI] = -5.29 to -0.55; P = 0.02). Improvement in OKS was significantly higher by 2.69 in FTCL group than in PTCL group (95% CI = -4.79 to -0.60; P = 0.01). However, the differences in OKSs were not clinically significant. The mean difference in AKS knee scores was similar between the 2 groups (95% CI = -9.14 to -3.34; P = 0.36), whereas the pooled mean difference in AKS function scores was higher by 5.63 in FTCL group than in PTCL group (95% CI = -9.27 to -1.98; P = 0.002), which was clinically relevant. The reoperation rates were statistically higher in PTCL group than in FTCL group (odds ratio = 2.24; 95% CI = 1.15 to 4.38; P = 0.02). Patients with FTCL achieved superior postoperative patient-reported outcomes and lower reoperation rates following UKA compared with those with PTCL. Thus, we believe this procedure should only be applied to end-stage medial osteoarthritis of the knee joint.

Difference Between Screw Cement Filling and Adequate Osteotomy With Thick Liner for Primary Total Knee Arthroplasty in Patients With Rand IIb Tibial Defects

BackgroundThe effectiveness of 2 treatment options, screw-cement fill, and adequate osteotomy with a thick liner, in treating patients with Rand IIb tibial defects (tibial plateau defects to a depth of 5 to 10 millimeters) in primary total knee arthroplasty (TKA) has not yet been demonstrated. Therefore, we performed a retrospective study to evaluate the differences between these 2 treatments. MethodsWe retrospectively analyzed patients who underwent primary TKA for Rand IIb tibial plateau defects from 2015 to 2020 from a department database. Patients were categorized into the screw-cement and thick liner groups based on the different options used to repair tibial defects. We evaluated Knee Society Score, range of motion (ROM), Insall-Salvati index (ISI), and Forgotten Joint Score (FJS) in both groups. We also compared differences in prosthesis survival, stiffness, myasthenia, and joint clicking between the 2 groups at mean 2 years postoperatively (range, 2 to 2.3). A power analysis was performed on the number of cases in the cohort. ResultsPostoperative femur-tibia mechanical axis (FTMA) correction was significantly higher in the screw-cement group than in the thick-liner group: 18.8 (±5.6°) versus 15.4 (±5.9°) (P < .01); At mean 2 years after surgery, the American Knee Society Functional Score improvement values were higher in the thick-liner group than in the screw-cement group: 36.3 (±12.4) versus 42.4 (±16.4) (P = .05). Postoperative ISI scores were 0.95 (±0.12) points in the screw-cement group and 0.89 (±0.13) points in the-thick liner group (P = .03). There were no statistically significant differences in the Knee Society Clinical Score, ROM, FJS, stiffness, myasthenia, joint clicking, and revision rate. ConclusionThe results of this study showed no significant difference in clinical outcomes between the 2 reconstruction strategies of the screw cement fill technique and the adequate osteotomy and thick liner technique for Rand IIb tibial plateau defects. However, in patients who have FTMA deformities greater than 20° or in younger patients who need to preserve bone volume, we recommend the screw cement filling technique to ensure stable postoperative results and to prepare these patients for possible later surgery.

Comparison of computer-assisted navigated technology and conventional technology in high tibial osteotomy (HTO): a meta-analysis

Background Though some studies have reported navigated high tibial osteotomy (HTO) is a useful procedure to correct knee deformity. There is still great controversy whether navigated HTO can achieve better accuracy of limb alignment and greater clinical outcomes. Current meta-analysis was conducted to investigate whether better radiographic outcomes and clinical outcomes could be acquired in navigated HTO compared with the conventional procedure. Method We conducted a literature search in the electronic databases, including Medline, Embase, the Cochrane Library, and Web of Science. We identified studies published before August 2020. We also checked the references of the related articles for any relevant studies. We strictly followed the Preferred Reporting Items for Systematics reviews and Meta-Analysis (PRISMA) guidelines in this review. This research was performed using Review Manager 5.4 software. Results Fourteen articles were included, involving 1399 knees. Our meta-analysis indicated that patients undergoing navigated HTO had significantly better outcomes in outliers of aimed limb alignment (RD=−0.24, 95% CI: =−0.34 to −0.13, p < 0.01), outliers of aimed tibial posterior slope (TPS) (RD=−0.41, 95% CI: −0.51 to −0.30, p < 0.01), Range of Motion (ROM) (MD = 6.37, 95%CI: 0.83–11.91, p = 0.02), and American knee society knee score (AKS knee score) (MD = 3.88, 95%CI: 1.37–6.39, p = 0.002). No significant differences were found in Lysholm score (MD = 1.30, 95%CI: −0.31 to 2.90, p = 0.11), American knee society function score (AKS function score) (RD = 1.42, 95%CI: −0.15 to 2.99, p = 0.08), complications (RD=−0.01, 95% CI: = −0.05 to 0.04, p = 0.77), delayed union (RD=−0.01, 95% CI: = −0.02 to 0.03, p = 0.59), and reoperation (RD = 0, 95% CI: −0.09 to 0.10, p = 0.98) between the two groups. The operation time in the navigated group was 15.46 min longer than in the conventional group. Conclusion Navigated HTO provided more accurate and reproducible radiographic outcomes in the correction of the malalignment than conventional techniques, and there is no difference in the risk of complications compared with conventional HTO. However, it is unclear whether navigation HTO can achieve better clinical results. More randomized controlled trials (RCTs) with high quality, large sample size, and sufficient follow-up period are required.

Comparison of Clinical Outcomes for Patients Treated With Gradually Reducing Radius Versus Single-Radius Total Knee Arthroplasty Systems.

The choice of implant used for primary total knee arthroplasty (TKA) may have an impact on clinical outcomes. Clinical outcomes after TKA with gradually reducing radius implants (group G) vs single-radius implants (group S) were evaluated among Asian patients. This study included 541 patients (754 knees) in group G and 187 patients (275 knees) in group S. Range of motion (ROM), flexion contracture, American Knee Society Knee and American Knee Society Function scores (KSKS and KSFS, respectively), and mechanical and anatomic tibiofemoral angles (MTFA and ATFA, respectively) were evaluated with electronic medical records. In univariate analysis, improvements in ROM, KSKS, and KSFS were significantly better in group G compared with group S at 1-year follow-up. Multivariable analyses showed greater ROM (4.52°, P=.002), decreased flexion contracture (-2.80°, P=.011), and improved KSKS (15.57, P<.001) at 1 year for group G vs group S. No significant differences in KSFS, MTFA, or ATFA were observed. Implant-related complications and radiologic loosening were not identified in either group at 2-year follow-up. The TKA implants with a gradually reducing radius showed greater 1-year improvements in ROM, flexion contracture, KSKS, and similar implant-related safety outcomes compared with a single-radius system. [Orthopedics. 2022;45(6):367-372.].

Influence of patellar denervation on anterior knee pain and knee function following total knee replacement: a systematic review and meta-analysis.

Previous studies have reached mixed results regarding the effects of patellar denervation with electrocautery (PD) on total knee replacement (TKR). This systematic review and meta-analysis aimed to summarize all available literatures to investigate the influence of PD on postoperative anterior knee pain (AKP) and knee function after TKR. Electronic databases, including PubMed, Cochrane Library and Embase, were searched from their inception to March 2021. Randomized controlled trials (RCT) and quasi-randomized controlled trials (quasi-RCT) comparing PD and non-patellar denervation (NPD) in TKR were selected, and the Cochrane risk of bias tool was used to assess the quality of included trials. AKP prevalence was defined as the primary outcome. A total of 12 RCTs and one quasi-RCT enrolled 1895 knees proved eligible. PD knees had significantly lower AKP prevalence than NPD knees (odds ratio [OR]=0.54; 95% confidence intervals [95% CI], 0.36-0.81; p=0.003). There was no difference between PD and NPD in terms of visual analogue scale for knee pain and range of motion, American knee society knee score, American knee society function score, patellar feller score, Oxford knee score for knee function. The results of subgroup analysis based on follow-up duration and patella resurfacing were in accordance with the results. PD knees were not associated with a higher risk of complication or revision. PD can significantly reduce the AKP prevalence following TKR without increasing the risk of complication and revision. Although the pain relief effect of PD may not be associated with improved knee function after TKR, this procedure is preferred in both patella resurfacing and patella non-resurfacing TKR.

Minimally invasive lateral unicompartmental knee replacement: Early results from an independent center using the Oxford fixed lateral prosthesis

PurposeThe aim of the present study was to assess clinical outcome as well as short-term survivorship of fixed-bearing lateral unicompartmental knee replacement (UKR) from a non-designer centre using the Oxford Fixed Lateral prosthesis. MethodsThis single-centre retrospective cohort study reports the short-term results of 51 consecutive patients (52 knees) after fixed-bearing lateral UKR with a minimum follow-up of one year. Survivorship analysis was performed with different endpoints and clinical outcome was measured using the Oxford Knee Score (OKS), objective American Knee Society Score (AKSS-O), range-of-motion (ROM), visual analog scale for pain (VAS), Tegner activity score and UCLA score. ResultsThere was no revision surgery, defined as exchange of at least one of the components resulting in a survival rate of 100% at two years. Three patients required further surgical treatment resulting in a survival rate of 94.2% (95% confidence interval (CI): 83.2–98.1%) with the endpoint ‘any reoperation’. Outcome scores, VAS and ROM showed a statistically significant improvement at final follow-up (P < .001). The OKS improved from 26.4 ± 6.9 (12–41) preoperatively to 39.7 ± 8.4 (15–48), the AKSS-O from 54.3 ± 15.3 (18–90) to 82.2 ± 15.6 (40–100), the American Knee Society Functional Score from 56.4 ± 21.3 (10–100) to 83.1 ± 20.2 (five to 100) and the ROM from 123.5 ± 13.5 (90–140) to 134 ± 10.3 (95–150). ConclusionEarly results of fixed-bearing lateral UKR using the Oxford-Fixed-Lateral prosthesis were encouraging with a significant improvement in pain and knee function as well as an excellent survivorship of 100% at a mean follow-up of two years. Further follow-up is necessary to evaluate the long-term effectiveness of this device and the surgical technique. Level of EvidenceLevel IV, retrospective cohort study.

Does the Surgeon-reported Outcome Correlate with Patient-reported Outcome after Total Knee Arthroplasty? A Cohort Study.

Background:Total knee arthroplasty (TKA) has been proved to be a successful and cost-effective treatment for improving pain and function in patients with knee arthritis. Total knee arthroplasty (TKA) is one of the most common orthopaedic surgeries performed worldwide and advancement in surgical techniques and prosthetic designs have improved the patient outcomes. However, concerns and priorities of patients and surgeons relating to joint replacement may differ.Materials and Methods:306 TKAs in 223 patients were evaluated for functional outcome using surgeon reported American Knee Society Knee Score (KS)/Functional Score (FS) and patient-reported Oxford Knee Score (OKS). We have also assessed the correlation between FS and OKS at midterm follow up.Results:The mean preoperative KS, FS, and OKS in 223 patients were 42.76, 42.4, and 38.84 and the midterm mean KS, FS, and OKS were 84.29, 73.40, and 30.26, respectively. There was a statistically significant improvement in the KS, FS, and OKS at midterm follow up in Category A (CAT A) (bilateral TKA or unilateral with asymptomatic contralateral knee), CAT B (unilateral TKA with symptomatic other knee) and CAT C (inflammatory arthritis). Overall, the correlation between the midterm FS and OKS was fair. However, in CAT A and CAT B, there was no significant correlation between FS and OKS, but CAT C had a strong correlation. There was a statistically significant improvement in the KS, FS, and OKS when midterm follow up scores were compared with preoperative scores. However, no significant correlation between the American knee society FS and OKS in osteoarthritic patients at midterm follow up signifies acceptable outcome may vary between patients and physicians.Conclusion:All patients should be counseled preoperatively to assess their expectations and sensitize them to information regarding the expected functional outcome following TKA in their cultural context.

Evidence-Based Indications for Mobile-Bearing Unicompartmental Knee Arthroplasty in a Consecutive Cohort of Thousand Knees

BackgroundThe indications for unicompartmental knee arthroplasty remain controversial. Previously recommended contraindications include the following: age under 60 years, weight 180 lb (82 kg) or over, patients undertaking heavy labor, chondrocalcinosis, and exposed bone in the patellofemoral joint. This study explores whether these contraindications are valid in mobile-bearing unicompartmental knee arthroplasty. MethodsUsing a prospective series of 1000 consecutive medial unicompartmental knee arthroplasties in which the reported contraindications were not applied, the functional outcome and survival in patients with or without contraindications were compared. ResultsOf the 1000 consecutive unicompartmental knee arthroplasties (818 patients), 68% (678 knees) would be considered contraindicated based on published contraindications. At a mean follow-up of 10 years (5-17), there was no difference in American Knee Society (AKS) Objective Scores (P = .05) or Oxford Knee Score (P = .08) between groups. However, knees with contraindications had significantly (P = .02) fewer poor outcomes and significantly better AKS Functional Scores (P < .001) and Tegner Activity Scores (P < .001). At 15 years, no difference in implant survival (P = .33) was observed. The 3% of unicompartmental knee arthroplasties performed in young men (age <60) weighing 180 lb or over with high activity levels, who have been reported to have poor outcomes after fixed-bearing unicompartmental knee arthroplasty, had significantly better AKS Functional Scores (P < .001), Oxford Knee Score (P = .01), and Tegner Activity Score (P < .001) at 10 years. No difference in AKS Objective Scores (P = .54) at 10 years or implant survival at 15 years (P = .75) was seen. ConclusionThis large case series provides evidence that patients with the previously reported contraindications do as well as, or even better than, those without contraindications. Therefore these contraindications should not apply to mobile-bearing unicompartmental knee arthroplasty.

How often is the office visit needed? Predicting total knee arthroplasty revision risk using pain/function scores.

BackgroundMost patients have favorable outcomes after primary total knee arthroplasty (TKA). Well-validated methods to predict the risk of poor outcomes have not been developed or implemented. Several patients have annual clinic visits despite well-funcitoning TKA, as a routine practice, to detect early failure requiring revision surgery. It is not known whether assessment of pain and function can be used as a predictive tool for early failure and revision to guide practice. Our objective was to determine whether pain and function can predict revision after TKA.MethodsWe retrospectively studied data from a large prospectively gathered TKA registry to examine changes in outcome scores for primary TKAs undergoing revision compared to those not requiring revision to determine the factors that are predictive for revision.ResultsOf the 1,012 patients, 721 had had a single-sided primary TKA and had American Knee Society (AKS) Scores for three or more visits. 46 patients underwent revision, 23 acutely (fracture, traumatic component failure or acute infection) and 23 for latent causes (late implant loosening, progressive osteolysis, or pain and indolent infection). Mean age was 70 years for the non-revision patients, and 64 years for those revised. Both AKS Clinical and AKS Function Scores for non-revised patients were higher than in revision patients, higher in acute revision compared to latent revision patients. Significant predictors of revision surgery were preoperative, 3- and 15-month postoperative AKS Clinical Scores and 3-month AKS Function Scores. At 15-month post-TKA, a patient with a low calculated probability of revision, 32 % or less, was unlikely to require revision surgery with a negative predictive value of 99 %.ConclusionTime dependent interval evaluation post-TKA with the AKS outcome scores may provide the ability to assign risk of revision to patients at the 15-month follow-up visit. If these findings can be replicated using a patient-reported measure, a virtual follow-up with patient-reported outcomes and X-ray review may be an alternative to clinic visit for patients doing well.Electronic supplementary materialThe online version of this article (doi:10.1186/s12913-016-1669-y) contains supplementary material, which is available to authorized users.

Effect of Joint Line Elevation after Posterior-stabilized and Cruciate-retaining Total Knee Arthroplasty on Clinical Function and Kinematics.

Background:Joint line (JL) is a very important factor for total knee arthroplasty (TKA) to restore. The objective of this study was to evaluate the early clinical and kinematic results of TKAs with posterior-stabilized (PS) or cruciate retaining (CR) implants in which the JL was elevated postoperatively.Methods:Data were collected from patients who underwent TKA in our department between April 2011 and April 2014. The patients were divided into two groups based on the prosthesis they received (PS or CR). At 1-year postoperatively, clinical outcomes were evaluated by the American Knee Society (AKS) knee score, AKS function score, and patella score. In vivo kinematic analysis after TKA was performed on all patients and a previously validated three-dimensional to two-dimensional image registration technique was used to obtain the kinematic data. Anteroposterior (AP) translation of the medial and lateral femoral condyles, and axial rotation relative to the tibial plateau, were analyzed. The data were assessed using the Mann–Whitney test.Results:At time of follow-up, there were differences in the AKS knee scores (P = 0.005), AKS function scores (P = 0.025), patella scores (P = 0.015), and postoperative range of motions (P = 0.004) between the PS group and the CR group. In the PS group, the magnitude of AP translation for the medial and lateral condyle was 4.9 ± 3.0 mm and 12.8 ± 3.3 mm, respectively. Axial rotation of the tibial component relative to the femoral component was 12.9 ± 4.5°. In the CR group, the magnitude of AP translation for the medial and lateral condyle was 4.3 ± 3.5 mm and 7.9 ± 4.2 mm, respectively. The axial rotation was 6.7 ± 5.9°. There were statistically different between PS group and CR group in kinematics postoperatively.Conclusion:Our results demonstrate that postoperative JL elevation had more adverse effects on the clinical and kinematic outcomes of CR TKAs than PS TKAs.

Severe arthritis predicts greater improvements in function following total knee arthroplasty.

Although excellent outcomes are routinely reported following total knee replacement, up to 20% of patients remain dissatisfied. The aim of this study was to determine whether pre-operative radiographic classification was associated with functional outcomes following surgery. A retrospective review of a prospective arthroplasty database identified 256 patients that fulfilled the inclusion criteria over an 18-month period. Baseline demographic data on all patients were collected prospectively. All pre-operative radiographs were assessed using the Kellgren and Lawrence (K&L) classification system. Patients were prospectively assessed using the American Knee Society Score pre-operatively and at 1, 3 and 5years post-surgery. An association was found between the pre-operative radiographic severity of arthritis and the pre-operative American Knee Society Knee (AKSK) scores, with worsening radiographic grade corresponding to worsening AKSK scores (p=0.020). There was an association between K&L classification and improvement in AKSK scores from pre-operative to 1year (p=0.003) and 3years (p=0.04), with K&L grades 3 and 4 demonstrating the most significant improvements. On multivariate regression analysis, K&L classification was the only significant predictor of improvement in AKSK at 1year (p=0.009). No correlation was found between K&L grade and the American Knee Society Functional Scores at any stage. The results of this study may help to improve satisfaction rates in total knee replacement by targeting treatment. Patients can be counselled that although radiographic severity of arthritic changes can predict knee-specific functional improvement, the extent of their global functional improvement cannot. IV.

Function of the extensor mechanism of the knee after using the 'patellar-loop technique' to reconstruct the patellar tendon when replacing the proximal tibia for tumour.

The aim of this study was to analyse the gait pattern, muscle force and functional outcome of patients who had undergone replacement of the proximal tibia for tumour and alloplastic reconstruction of the extensor mechanism using the patellar-loop technique. Between February 1998 and December 2009, we carried out wide local excision of a primary sarcoma of the proximal tibia, proximal tibial replacement and reconstruction of the extensor mechanism using the patellar-loop technique in 18 patients. Of these, nine were available for evaluation after a mean of 11.6 years (0.5 to 21.6). The strength of the knee extensors was measured using an Isobex machine and gait analysis was undertaken in our gait assessment laboratory. Functional outcome was assessed using the American Knee Society (AKS) and Musculoskeletal Tumor Society (MSTS) scores. The gait pattern of the patients differed in ground contact time, flexion heel strike, maximal flexion loading response and total sagittal plane excursion. The mean maximum active flexion was 91° (30° to 110°). The overall mean extensor lag was 1° (0° to 5°). The mean extensor muscle strength was 25.8% (8.3% to 90.3%) of that in the non-operated leg (p < 0.001). The mean functional scores were 68.7% (43.4% to 83.3%) (MSTS) and 71.1 (30 to 90) (AKS functional score). In summary, the results show that reconstruction of the extensor mechanism using this technique gives good biomechanical and functional results. The patients' gait pattern is close to normal, except for a somewhat stiff knee gait pattern. The strength of the extensor mechanism is reduced, but sufficient for walking.

Longer hospital stay, more complications, and increased mortality but substantially improved function after knee replacement in older patients

Background and purpose — Total knee replacement (TKR) is being increasingly performed in elderly patients, yet there is little information on specific requirements and complication rates encountered by this group. We assessed whether elderly patients undergoing TKR had different length of stay, requirements, complication rates, and functional outcomes compared to younger counterparts.Patients and methods — We analyzed prospectively gathered data on 3,144 consecutive primary TKRs (in 2,092 patients aged less than 75 years, 694 patients aged between 75 and 80 years, and 358 patients aged over 80 years at the time of surgery).Results — Incidence of blood transfusion, urinary catheterization, postoperative confusion, cardiac arrhythmia, and 1-year mortality increased with age, even after adjusting for confounding factors, whereas the incidences of chest infection and mortality at 1 month were highest in those aged 75–80. Rates of thromboembolism, prosthetic infection, and revision were similar in the 3 age groups. All groups showed similar substantial improvements in American Knee Society (AKS) knee scores, which were maintained at 5 years. Older patients had smaller improvements in AKS function score, which deteriorated between 3 and 5 years postoperatively, in contrast to the younger group.Interpretation — Elderly people stand to gain considerably from TKR, particularly in terms of pain relief, and they should not be denied surgery based solely on age. However, they should be warned that they can expect a longer length of stay, a higher requirement for blood transfusion and/or urinary catheterization, and more medical complications postoperatively. Mortality was also higher in the older age groups. The risks have been quantified to assist in perioperative counselling, informed consent, and healthcare planning.

Does Electric Stimulation of the Vastus Medialis Muscle Influence Rehabilitation After Total Knee Replacement?

Patients with knee osteoarthritis present with reduced quadriceps muscle strength, which is partially responsible for impaired function and disability. Although total knee replacement (TKR) is an effective surgical procedure, residual muscle weakness is not usually addressed and may persist for years postoperatively. This article reports the results of a prospective, randomized, controlled trial evaluating the effect of electric muscle stimulation of the vastus medialis on the speed and effort of walking, quality of life, and knee performance in patients undergoing TKR. Seventy patients who underwent TKR were randomly divided into 2 groups. Patients in group A received electric muscle stimulation and standard physiotherapy for 6 weeks, while patients in group B received physiotherapy only. All patients were assessed with both subjective and objective clinical scales preoperatively and at 6, 12, and 52 weeks postoperatively. Patients in group A demonstrated a statistically significant increase in walking speed, Oxford Knee Score, and American Knee Society function score compared to those in group B at 6 weeks (P=.003, .001, and .001, respectively) and at 12 weeks (all P=.001). A statistically significant increase in the SF-36 physical component summary score was observed at 6, 12, and 52 weeks (all P=.001). Three patients found the sensation of the electrical stimulation uncomfortable and abandoned its use. No skin reactions and surgical site infections were observed. Electrical stimulation of the vastus medialis muscle in addition to conventional physiotherapy improves functional recovery and early rehabilitation after TKR.

Minimally invasive Oxford phase 3 unicompartmental knee replacement

This prospective study describes the outcome of the first 1000 phase 3 Oxford medial unicompartmental knee replacements (UKRs) implanted using a minimally invasive surgical approach for the recommended indications by two surgeons and followed up independently. The mean follow-up was 5.6 years (1 to 11) with 547 knees having a minimum follow-up of five years. At five years their mean Oxford knee score was 41.3 (sd 7.2), the mean American Knee Society Objective Score 86.4 (sd 13.4), mean American Knee Society Functional Score 86.1 (sd 16.6), mean Tegner activity score 2.8 (sd 1.1). For the entire cohort, the mean maximum flexion was 130° at the time of final review. The incidence of implant-related re-operations was 2.9%; of these 29 re-operations two were revisions requiring revision knee replacement components with stems and wedges, 17 were conversions to a primary total knee replacement, six were open reductions for dislocation of the bearing, three were secondary lateral UKRs and one was revision of a tibial component. The most common reason for further surgical intervention was progression of arthritis in the lateral compartment (0.9%), followed by dislocation of the bearing (0.6%) and revision for unexplained pain (0.6%). If all implant-related re-operations are considered failures, the ten-year survival rate was 96% (95% confidence interval, 92.5 to 99.5). If only revisions requiring revision components are considered failures the ten-year survival rate is 99.8% (confidence interval 99 to 100). This is the largest published series of UKRs implanted through a minimally invasive surgical approach and with ten-year survival data. The survival rates are similar to those obtained with a standard open approach whereas the function is better. This demonstrates the effectiveness and safety of a minimally invasive surgical approach for implanting the Oxford UKR.

The Avon patellofemoral joint replacement

We present a prospective review of the two-year functional outcome of 37 Avon patellofemoral joint replacements carried out in 29 patients with a mean age of 66 years (30 to 82) between October 2002 and March 2007. No patients were lost to follow-up. This is the first independent assessment of this prosthesis using both subjective and objective analysis of outcome. At two years the median Oxford knee score was 39 (interquartile range 32 to 44), the median American Knee Society objective score was 95 (interquartile range 90 to 100), the median American Knee Society functional score was 85 (interquartile range 60 to 100), and the median Melbourne Knee score was 28 (interquartile range 21 to 30). Two patients underwent further surgery. Only one patient reported an unsatisfactory outcome. We conclude that the promising early results observed by the designing centre are reproducible and provide further support for the role of patellofemoral joint replacement.