Unicompartmental arthritis of the knee

The role of navigation in high tibial osteotomy: a study of 50 patients

From October 1, 2007, to October 10, 2008, we performed 50 navigated high tibial osteotomies (medial opening wedge). The mean age of the patients was 46.58 years (range, 16-70). Twenty-three osteotomies were performed in women and 27 in men. Two patients received osteotomies on both sites. Average malalignment was 6.4 degrees varus (range, 3 degrees -10.8 degrees ). Sixteen osteotomies were performed on the right side and 34 on the left side. Detailed preoperative planning was performed using the digital MediCad (Hectec GmbH, Niederviehbach, Germany) program based on the malalignment test. Navigation data were compared using full weight-bearing and intraoperative radiographs. Navigation was shown to be an excellent device for intraoperative control of the amount of correction achieved and offers additional information regarding the lateral plain, ligaments, flexion and extension.

Medial unicompartmental knee arthroplasty with Miller-Galante II prosthesis: mid-term clinical and radiographic results

AIM

The purpose of our study was to evaluate retrospectively the mid-term results of the Miller-Galante II (Zimmer, Warsaw, USA) unicondylar knee arthoplasty (UKA).

METHOD

The study included 46 patients with medial UKAs. Mean follow-up time was 7.0 years (range 2.7-13.1 years).

RESULTS

Survival rate of the prosthesis was 86.6% (95% CI 73.7-99.6) at 7 years. The mean clinical and functional Knee Society Scores had increased from 51 and 62 points preoperatively to 76 and 93 points (P < 0.001) postoperatively. Five of the 46 knees were revised because of excessive wear of the polyethylene liner, and three due to progression of the osteoarthritis in the lateral compartment of the knee.

CONCLUSION

Survival of this fixed-bearing UKA was not as good as previously reported and polyethylene wear seems to be a more common problem than previously assumed.

Comparison of minimally invasive unicompartmental knee arthroplasty with or without a navigation system

The authors investigated the hypothesis that navigation system-assisted minimally invasive unicompartmental knee arthroplasty (NA-MIS UKA) produces better short-term clinical results than MIS UKA without a navigation system. After a minimum 2-year follow-up, short-term functional results and component alignment accuracies of 31 knees that underwent NA-MIS UKA (the NA-MIS group) were compared with those of 33 knees that underwent MIS UKAs without a navigation system (the MIS group). The Hospital for Special Surgery and Western Ontario and McMaster Universities Osteoarthritis Index scores of 2 groups showed significant improvement at final follow-ups, but no significant intergroup differences were observed (P = .071 and P = .096, respectively). However, NA-MIS UKA produced more improvement in the desired mechanical axis and a lower percentage of prosthetic alignment outliers than MIS UKA.

Sports activities after lower limb osteotomy

INTRODUCTION

Active sports participation can be important in some patients with degenerative joint disease in the lower limb. We investigated whether this is possible after an osteotomy for osteoarthritis of the hip, knee and ankle joints.

SOURCES OF DATA

We performed a literature search using Medline, Cochrane, CINAHL and Google Scholar with no restriction to time period or language using the keywords: 'osteotomy and sports'. Eleven studies (all level IV evidence) satisfied our inclusion and exclusion criteria. Nine reported on high tibial osteotomies, one on periacetabular osteotomies and one on distal tibial osteotomies. The Coleman Methodology Score to assess the quality of studies showed much heterogeneity in terms of study design, patient characteristics, management methods and outcome assessment.

AREAS OF AGREEMENT

Participation in recreational sports is possible in most patients who were active in sports before lower limb osteotomy. In no study were patients able to participate in competitive sports.

AREAS OF CONTROVERSY

Intensive participation in sports after osteotomy may adversely affect outcome and lead to failures requiring re-operation.

GROWING POINTS

Patients may be able to remain active in selected sports activities after a lower limb osteotomy for osteoarthritis. More rapid progression of arthritis is however a possibility.

AREAS TIMELY FOR DEVELOPING RESEARCH

Prospective comparative studies investigating activities and sports participation in age-matched patients undergoing osteotomy or joint replacement could lead to useful conclusions. Increased activity and active sports participation may lead to progression of arthritis and earlier failure requiring additional surgery.

Unicompartmental knee arthroplasty for tricompartment osteoarthritis in octogenarians

BACKGROUND

Unicompartmental knee arthroplasty (UKA) is specifically indicated in isolated unicompartmental arthritis with competent ligaments. Recent series of UKA for unicompartmental arthritis have shown good function, persistence of pain relief, and nearly 90% survivorship at 15 years, even in knees that would perhaps not be considered good indications for UKA today. The perioperative morbidity of UKA is less than total knee arthroplasty. We present our series of 19 octogenarians with tricompartment osteoarthritis (predominant medial compartment involvement) treated with UKA as definitive surgery.

MATERIALS AND METHODS

We performed UKA on 29 knees (19 patients) average 83 years (79-94 years) of either sex from Jan 2002 to Dec 2006. All the patients had tricompartment knee osteoarthritis (with predominant medial and some patellofemoral compartment involvement).

RESULTS

The results were evaluated using the Knee Society scores and visual analogue score over an average 48-month follow-up (range, 24 to 81 months). Barring one (medial femoral condyle fracture detected on postoperative radiography), all patients achieved promised levels of satisfaction.

DISCUSSION

UKA for tricompartment knee arthritis in the young active patient entails risk of dissatisfaction and failure. We present UKA in select 'very elderly' patients with tricompartment osteoarthritis (with predominant unicompartment involvement).

Comparison of survival and cost-effectiveness between unicondylar arthroplasty and total knee arthroplasty in patients with primary osteoarthritis: a follow-up study of 50,493 knee replacements from the Finnish Arthroplasty Register

BACKGROUND AND PURPOSE

Both unicondylar arthroplasty (UKA) and total knee arthroplasty (TKA) are commonly used for the treatment of unicompartmental osteoarthritis (OA) of the knee. The long-term survivorship and cost-effectiveness of these two treatments have seldom been compared on a nationwide level, however. We therefore compared the survival of UKA with that of TKA and conducted a cost-benefit analysis comparing UKA with TKA in patients with primary OA.

PATIENTS AND METHODS

We analyzed 1,886 primary UKAs (3 designs) and 48,607 primary TKAs that had been performed for primary OA and entered in the Finnish Arthroplasty Register between 1980 and 2003 inclusive.

RESULTS

UKAs had a 60% (95% CI: 54-66) survival rate and TKAs an 80% (95% CI: 79-81) survival rate at 15 years with any revision taken as the endpoint. Overall survival of UKAs was worse than that of TKAs (p < 0.001). All 3 UKA designs had poorer overall survival than the corresponding TKA designs. In the theoretical cost-benefit analysis, the cost saved by lower implant prices and shorter hospital stay with UKA did not cover the costs of the extra revisions.

INTERPRETATION

At a nationwide level, UKA had significantly poorer long-term survival than TKA. What is more, UKA did not even have a theoretical cost benefit over TKA in our study. Based on these results, we cannot recommend widespread use of UKA in treatment of unicompartmental OA of the knee.

Revision of 33 unicompartmental knee prostheses using total knee arthroplasty: strategy and results

The purpose of this study was twofold: to evaluate the radiological and clinical results of 33 total knee arthroplasties (TKA) implanted between January 1993 and March 2005, to replace failed medial unicompartmental knee arthroplasty (UKA), and to develop a strategy to deal with bone defects in the tibial plateau. Failure was due to: tibial loosening (15 cases), femoral loosening (five cases), femoral and tibial loosening (two cases), polyethylene wear (five cases), lateral compartment osteoarthritis (two cases), patellofemoral osteoarthritis (two cases), laxity and PE dislocation (one case), and sepsis in one case. In 12 cases the tibial bone defect was filled with a metallic wedge, in seven we used an allograft (femoral head), and in one we used both. We report the results of 27 cases (five patients died and one was lost to follow-up). The mean follow-up was 73+/-41.7 months (range, 8-153) and the global IKS score was 166.72+/-21.3 points (range, 128-200). X-rays of the eight allografts showed osteointegration in all cases and no radiolucency was noted.

Yearly incidence of unicompartmental knee arthroplasty in the United States

Our purpose was to estimate the incidence of unicompartmental knee arthroplasty in the United States. Three major implant manufacturers provided data over an 8-year period from 1998 to 2005. In addition, a database from 44 hospitals was used to derive national estimates for implants manufactured by all other companies. The incidence of unicompartmental knee arthroplasty ranged from 6570 implants in 1998 to 44990 in 2005. Unicompartmental knee arthroplasty increased at an average rate of 32.5% during the study period compared with a 9.4% average increase in rate of total knee arthroplasty over the same period. Although unicompartmental arthroplasty is growing at triple the rate of total knee arthroplasty in the United States, the data suggest that unicompartmental implants currently account for less than 8% of all knee arthroplasty procedures.

The effects of hip muscle strengthening on knee load, pain, and function in people with knee osteoarthritis: a protocol for a randomised, single-blind controlled trial

Background

Lower limb strengthening exercises are an important component of the treatment for knee osteoarthritis (OA). Strengthening the hip abductor and adductor muscles may influence joint loading and/or OA-related symptoms, but no study has evaluated these hypotheses directly. The aim of this randomised, single-blind controlled trial is to determine whether hip abductor and adductor muscle strengthening can reduce knee load and improve pain and physical function in people with medial compartment knee OA.

Methods/Design

88 participants with painful, radiographically confirmed medial compartment knee OA and varus alignment will be recruited from the community and randomly allocated to a hip strengthening or control group using concealed allocation stratified by disease severity. The hip strengthening group will perform 6 exercises to strengthen the hip abductor and adductor muscles at home 5 times per week for 12 weeks. They will consult with a physiotherapist on 7 occasions to be taught the exercises and progress exercise resistance. The control group will be requested to continue with their usual care. Blinded follow up assessment will be conducted at 12 weeks after randomisation. The primary outcome measure is the change in the peak external knee adduction moment measured during walking. Questionnaires will assess changes in pain and physical function as well as overall perceived rating of change. An intention-to-treat analysis will be performed using linear regression modelling and adjusting for baseline outcome values and other demographic characteristics.

Discussion

Results from this trial will contribute to the evidence regarding the effect of hip strengthening on knee loads and symptoms in people with medial compartment knee OA. If shown to reduce the knee adduction moment, hip strengthening has the potential to slow disease progression.

Trial Registration

Australia New Zealand Clinical Trials Registry ACTR12607000001493

Unicompartmental knee arthroplasty for the treatment of unicompartmental osteoarthritis: a systematic study

Unicompartmental knee arthroplasty (UKA), total knee arthroplasty (TKA) and high tibial osteotomy (HTO) may all be used to treat unicompartmental osteoarthritis, but they are often used for different patient groups. However, there is considerable overlap in indications for all three options. The aim of this review was to assess the safety and efficacy of UKA compared with TKA and HTO in unicompartmental osteoarthritis. Studies that compared UKA with either TKA or HTO were identified and included for review. For knee function and postoperative pain, UKA appeared similar to TKA and HTO at 5 years follow up. Range of motion was better in UKA compared with TKA. Complication rates after UKA and TKA appeared similar, although deep vein thrombosis was reported more often after TKA. There were more complications after HTO than UKA. Survival of UKA prostheses was approximately 85-95%, compared with at least 90% for TKA at 10 years follow up. Survivorship for HTO appeared to be less than 85%. It was not clear whether there were more revisions after UKA than TKA, but there appeared to be fewer revisions in UKA compared with HTO. UKA is considered at least as safe as TKA and HTO. For function, UKA appears to be at least as efficacious as TKA and HTO. The survival of UKA compared with TKA and HTO cannot be determined based on the available evidence.

Unicondylar knee replacement for primary osteoarthritis: a prospective follow-up study of 1,819 patients from the Finnish Arthroplasty Register

BACKGROUND

The choice and use of unicondylar knee arthroplasty (UKA) has gone through a nation wide resurgence at the start of the 21st century in Finland. We evaluated the population-based survival of UKA in patients with primary osteoarthritis (OA) in Finland, and the factors affecting their survival.

METHOD

The Finnish Arthroplasty Register was established in 1980. During the years 1985-2003, 1,928 primary UKAs were recorded in the register; 1,819 of these were performed for primary OA. Of these 1,819 UKAs, we selected for further analysis implants that had been used in more than 100 operations during the study period. The survival rates of UKAs were analyzed using Kaplan-Meier analysis and the Cox regression model.

RESULTS

Analysis of the whole study period showed that UKAs had a 73% (95% CI: 70-76) survival rate at 10 years, with revision for any reason as the end point. Those patients who received the Oxford menisceal bearing unicondylar (n = 1145) had a survival rate of 81% (95% CI: 72-89) at 10 years. The group that received the Miller-Galante II unicondylar (n = 330) had a 79% survival rate (95% CI: 71-87) at 10 years, whereas the Duracon (n = 196) had a survival rate of 78% (95% CI: 72-84) and the PCA (n = 146) had a survival rate of 53% (95% CI: 45-60) at 10 years. The number of UKA operations in Finland has increased markedly in recent years. At the time of operation, the mean age of the patients was 65 (38-91) years. Younger patients (<or= 65 years of age) were found to have a 1.5-fold (95% CI: 1.1-2.0; p = 0.04) increased risk of revision compared to older patients (< 65 years).

INTERPRETATION

UKA is a viable option for the treatment of unicompartmental osteoarthritis of the knee. However, patients should be made aware of the lower survival of the UKAs compared with total knee arthroplasties.

Test–retest reliability of the peak knee adduction moment during walking in patients with medial compartment knee osteoarthritis

OBJECTIVE

To estimate the test-retest reliability of the peak external knee adduction moment during walking in patients with medial compartment knee osteoarthritis (OA), and to describe the interpretation of the reported values.

METHODS

A total of 31 patients diagnosed with knee OA confined primarily to the medial compartment underwent quantitative gait analyses during 2 separate test sessions at least 24 hours apart and within 1 week. The peak knee adduction moment was calculated for each patient at each session based on the mean of 5 walking trials. Reliability was estimated using the intraclass correlation coefficient (ICC(2,1)) and the standard error of measurement (SEM).

RESULTS

The mean difference in peak adduction moments between test sessions was 0.1% body weight x height (BW x ht; 95% confidence interval [95% CI] -0.1, 0.3). The point estimate for the ICC was 0.86 (95% CI 0.73, 0.96). The point estimate for the SEM was 0.36% BW x ht (95% CI 0.29, 0.48).

CONCLUSION

The ICC suggests that the peak knee adduction moment is appropriate for use when distinguishing among patients, for example, in studies of various interventions intended to decrease dynamic load on the knee medial compartment. The SEM illustrates the importance of considering measurement error and incorporating confidence levels when interpreting an individual patient's peak knee adduction moment value.

The oblique high tibial osteotomy technique without bone removal and with rigid blade plate fixation for the treatment of medial osteoarthritis of the varus knee: medium and long-term results

Several high tibial osteotomy (HTO) surgical techniques for the treatment of medial osteoarthritis of the varus knee have been reported. Their main objectives are the achievement of the precise correction that is necessary for the lower limb mechanical axis realignment and the alleviation of the medial joint space. Early or late recurrence of the varus deformity must be avoided and various methods of fixation have been proposed to obtain this. We present a method of single level oblique HTO with no bone removal and with blade plate fixation for the treatment of medial osteoarthritis of the knee. One hundred seventeen patients (136 knees) were operated using this technique during a 12.2-year period. In 4.5 years follow-up there were 73.8% satisfactory results while in 8.4 years follow-up there were 61.1% satisfactory results. There were 11 complications: five patients with deep vein thrombosis, four with superficial wound infection and two with temporary peroneal nerve dysfunction. This study presents the operative technique in details, evaluates the results and assesses the advantages and disadvantages of the method in relation to other techniques described in the literature.

Subchondral bone overgrowth in the presence of full-thickness cartilage defects in the knee

Between October 2000 and December 2003, 252 autologous chondrocyte implants were performed in 183 patients. Eighty lesions showed overgrowth of the subchondral bone plate under the chondral lesion, this was termed a "bone boss." Thirty-seven were on the medial femoral condyle (MFC), 18 on the lateral femoral condyle (LFC), 21 in the trochlea and 4 on the patella. There was a statistically significant association between the LFC and "bone boss." The lesions showing this finding were of a larger area (3.4 cm2 and 2.8 cm2 respectively, p=0.006), and had more diffuse chondral changes than lesions without. The patients with a "bone boss" had a tendency to longer duration of symptoms (85.3 months and 64.3 months respectively, p=0.089). The "bone bosses" were resected back to the level of the surrounding subchondral bone prior to implantation. Radiological and clinical follow-up showed no statistical difference between the two groups. A discussion of the possible aetiology of the "bone boss" is made.

Rehabilitation of orthopedic and rheumatologic disorders. 2. Osteoarthritis assessment, treatment, and rehabilitation

This self-directed learning module discusses a patient with knee osteoarthritis and addresses the clinical presentation, assessment, medical management, rehabilitation approaches, and surgical options. It is part of the chapter on osteoarthritis in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This chapter emphasizes the differential diagnosis, clinical diagnostic considerations, current pharmacology, orthotics, exercise interventions, and surgical procedure options for a patient with knee osteoarthritis.

OVERALL ARTICLE OBJECTIVE

To summarize diagnostic considerations and management of knee osteoarthritis.

Minimally invasive total knee arthroplasty

Currently, minimally invasive total knee arthroplasty is defined as an incision length of < 14 cm. However, the length of the incision is not the primary influence on potential postoperative benefits to the patient and should not be the only characteristic of the minimally invasive approach for knee arthroplasty. Some other factors that should also be included in this definition are: 1. The amount of soft-tissue dissection (including muscle, ligament, and capsular damage). 2. Patellar retraction or eversion. 3. Tibiofemoral dislocation. Minimally invasive surgery should not be considered to be a cosmetic procedure but rather one that addresses patients' concerns with regard to postoperative pain and slow rehabilitation. Standard total knee arthroplasties provide pain relief, but returning to activities of daily living remains a challenge for some individuals, who may take several weeks to recover. Several studies have demonstrated long-term success (at more than ten years) of standard total knee arthroplasties. However, many patients remain unsatisfied with the results of the surgery. In a study of functional limitations of patients with a Knee Society score of > or = 90 points after total knee arthroplasty, only 35% of patients stated that they had no limitations. This finding was highlighted in a study by Dickstein et al., in which one-third of the elderly patients who underwent knee replacement were unhappy with the outcome at six and twelve months postoperatively. Although many surgeons utilize objective functional scoring systems to evaluate outcome, it is likely that the criteria for a successful result of total knee arthroplasty differ between the patient and the surgeon. This was evident in a report by Bullens et al., who concluded that surgeons are more satisfied with the results of total knee arthroplasty than are their patients. Trousdale et al. showed that, in addition to concerns about long-term functional outcome, patients' major concerns were postoperative pain and the time required for recovery. Patients undergoing total knee arthroplasty have specific functional goals, such as climbing stairs, squatting, kneeling, and returning to some level of low-impact sports after surgery. Our clinical investigations demonstrated that the minimally invasive surgical approach reduces hospital stays, decreases postoperative pain, and decreases rehabilitation needs as well as enables patients to return to normal function more quickly. It is important for surgeons to take an evolutionary, rather than a revolutionary, approach when performing minimally invasive total knee arthroplasty. The surgeon should downsize incisions progressively to prevent severe damage to the quadriceps mechanism. Extensive open exposure, prolonged patellar eversion, and dislocation of the tibiofemoral joint should evolve into a vastus medialis muscle split with patellar subluxation, retraction but not dislocation of the patella, and avoidance of gross dislocation of the tibiofemoral joint. Developing the techniques of minimally invasive total knee arthroplasty may be difficult and time-consuming, but patient benefits and satisfaction should outweigh the extra effort required. These changes require well-designed clinical studies to further document their effectiveness.

Minimally invasive total knee arthroplasty: a 10-feature evolutionary approach

There should not be a revolution to MIS-TKA but rather an evolutionary approach. This includes progressively downsizing incisions and causing less damage to the quadriceps mechanism. Previously,there was an extensive open exposure prolonged patella eversion and dislocation of the tibio-femoral joint. This should be evolved into a VMO muscle split with patella subluxation, retraction but not dislocation, and no gross dislocation of the tibio-femoral joint. Although the present MIS-TKA technique can be difficult and time-consuming, the resulting patient benefits should outweigh the extra effort required. In the future, we may use bone cuts and implantation with computer navigation. Each advance, however, will require new techniques, instrumentation, implants, and careful clinical studies. Caution should be taken by surgeons to avoid revolutionary approaches with existing implants, because they harbor a risk of catastrophic failure.