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1.

Background

Coronal plane alignment is one of the contributing factors to polyethylene wear in total knee arthroplasty.

Methods

Based on 95 retrieved polyethylene inserts, wear and damage patterns were analyzed in relationship to the overall mechanical alignment and to the position of the tibial component.

Results

A progression of wear was observed with progressively mechanical varus alignment. However, there was significantly more damage in the lateral compartment in the mild and moderate varus group compared to the valgus group. No difference in damage was seen between all groups for tibial component positioning in valgus or varus.

Conclusion

Progressive wear was observed with progressively varus alignment with more damage at the lateral side. This observation is unique and might be explained by lateral condylar lift-off inducing impact and shear loading in the varus group.  相似文献   

2.

Background

The purpose of this study is to investigate whether varus-valgus laxity of cruciate-retaining (CR) total knee arthroplasty (TKA) changes between 1 year and >5 years after surgery based on postoperative limb alignment.

Methods

One hundred twenty-one varus osteoarthritic knees that underwent CR TKA were included. The minimum follow-up was 5 years. Weight-bearing full-leg radiographs were obtained postoperatively and the hip-knee-ankle (HKA) angle was measured. Knees were grouped in varus (HKA angle ≤ ?3°, 47 knees) and neutral groups (?3° < HKA angle < 3°, 70 knees). The range of motion was measured and a Hospital for Special Surgery score was obtained at the last follow-up. Varus-valgus laxity at 15° of knee flexion was measured with stress radiographs after 1 year and at the last follow-up.

Results

No knees required revision surgery. The mean knee flexion angle (121.0° vs 117.1°) and Hospital for Special Surgery score (90.3 vs 90.4) at the last follow-up were not significantly different between the varus and neutral groups. In both groups, there was no significant change in varus or valgus laxity between 1 year and at the last follow-up.

Conclusion

Postoperative residual varus limb alignment did not lead to increasing varus laxity after CR TKA in the mid-term.  相似文献   

3.

Background

Unicompartmental knee arthroplasty (UKA) is an underutilized implant for medial tibiofemoral arthritis despite proven benefits in performance and reduced complications. This is likely related to registry recorded higher revision rates compared with total knee arthroplasty. It is our feeling that better component alignment resulting from the usage of computer-assisted surgery should improve longer-term functional results and survival of UKAs.

Methods

Between August 2003 and June 2007, 265 medial UKAs were performed in 264 consecutive patients using navigation.

Results

Eighty-eight women and 176 men with an average age of 51.7 (±4.63) years were assessed for function and survival over a follow-up period of 92.6 (63-120) months (7.7 years). The final survival rate over 5 years for this cohort was 97.6% at 5 years.

Conclusion

We conclude that computer-assisted UKA, to treat medial tibiofemoral joint arthritis, produces 5-year survival rates that are comparable with total knee arthroplasty.  相似文献   

4.

Background

Increased range of motion to higher degrees of flexion following total knee arthroplasty has been postulated to increase implant damage and revision rates, even in designs modified to accommodate high flexion.

Methods

We examined posterior-stabilized and high-flexion retrieved tibial inserts to look for differences in polyethylene surface damage with light microscopy and 3D deviation with laser scanning between inserts from patients who achieved a high degree of flexion (≥120° postoperatively) and inserts from patients who did not reach a high degree of flexion.

Results

No differences were found in damage scores on the articular and backside surfaces, except for abrasion in the posterior articular regions, or in 3D deviations between patients who reached a high degree of flexion and patients who did not. These results were independent of the reason for revision.

Conclusion

In our series, reaching a high degree of flexion did not influence surface damage or 3D deviation of the polyethylene inserts.  相似文献   

5.

Background

Obtaining adequate exposure while maintaining the integrity of the extensor mechanism is crucial to the success of revision knee arthroplasty. This is particularly important in infected cases where staged procedures are necessary. While the use of a long, tibial tubercle osteotomy (TTO) is an established method to improve exposure, controversy still exists concerning complication rates and sequential use.

Methods

Forty-two TTOs were performed in revision knee arthroplasties between 2009 and 2015. Follow-up period ranged from 3 to 24 months. Twenty-four TTOs were performed for single-stage revisions, and 18 TTOs were performed for 2-stage infected revisions. In infected cases, the initial osteotomy was left unfixed between stages. Screws were used to fix the osteotomy flap in all cases.

Results

All osteotomies united with no fractures, and there were no extensor lags. Minor proximal migration was noted in 1 case, and refixation was required in another. Greater range of motion (ROM) and improved Oxford Knee Scores were achieved in the single-stage revision group. In the infected 2-stage group, sequential use did not decrease union rates, and infection was eradicated in 14 of the 16 knees (88%).

Conclusion

We conclude that TTO is a safe and reproducible procedure when exposure needs improving in revision knee arthroplasty. In 2-stage revisions, sequential osteotomies do not decrease union rates, and leaving the osteotomy unfixed after the first stage does not cause any adverse issues.  相似文献   

6.

Background

In total hip arthroplasty (THA) of hips with coxa vara, the femoral stems might be inserted in a varus alignment. To avoid varus insertion, we designed a technique, which we termed “trochantoplasty.” In this procedure, the medial half of the greater trochanter was removed during THA.

Methods

We evaluated 30 patients (31 hips) who had coxa vara deformity and underwent THA using trochantoplasty at the mean follow-up of 5 years (range, 3-9 years).

Results

All stems were inserted in the neutral position. One Vancouver type 1 periprosthetic femoral fracture occurred after a fall at postoperative 2 months. At the latest follow-up, the mean power of abductor was 4.3 (range, 3-5). Four patients had moderate limp whereas 26 patients had slight limp. The abduction at 90° flexion ranged from 15° to 45° (mean, 35°). There was no revision. All prostheses had bone-ingrown stability without any detectable wear or osteolysis. The mean Harris hip score was improved from 66.9 to 89.4 points.

Conclusion

Trochantoplasty can be used to avoid varus insertion of the femoral stem while performing THA in patients with coxa vara deformity without compromising the abductor mechanism.  相似文献   

7.

Background

The loss of anatomic references and bone stock turns unicompartmental knee arthroplasty (UKA) revision surgery difficult, and according to some authors, it is technically as challenging as a total knee arthroplasty (TKA) revision surgery.

Methods

A retrospective review of 559 Oxford medial UKA was performed between 2007 and 2013. Nineteen knees were revised to TKA for reasons other than infection, most commonly for osteoarthritis progression.

Results

The most frequent cause of failure in our series was osteoarthritis progression (10 cases, 52.63%). In 15 patients (78.95%), tibial stems were needed, and in 10 (55.5%), metallic blocks for augmentation of tibial plateau were used. Postoperative radiographic studies showed a correct implant alignment, preserving adequate joint line (24.8 mm), and patellar (1.1 mm) height (according to Insall-Salvati). After a mean follow-up of 21 months (range 6-51) mean values of 78.8 (standard deviation [SD] = 16.8) and 62.3 (SD = 19.6) were obtained for the physical and mental scores of the Knee Society Score test. In the SF-36 tests mean values of 45.2 (SD = 7.6) and 53 (SD = 5.2) were obtained for the physical and mental scores respectively. In one case, a varus/valgus instability occurred intraoperatively and it required revision with a prosthesis with higher constriction. No thromboembolic or infectious events were observed during postoperative follow-up.

Conclusion

Following a standardized technique, UKA revision surgery can be achieved with TKA in almost every case despite bone stock loss and lack of anatomic landmarks.  相似文献   

8.

Background

Stress shielding is a well-recognized complication associated with total knee arthroplasty. However, this phenomenon has not been thoroughly described. Specifically, no study to our knowledge has evaluated the radiographic impact of utilizing various tibial component compositions on tibial stress shielding.

Methods

We retrospectively reviewed 3 cohorts of 50 patients that had a preoperative varus deformity and were implanted with a titanium, cobalt chromium (CoCr), or an all polyethylene tibial implant. A radiographic comparative analysis was performed to evaluate the amount of medial tibial bone loss in each cohort. In addition, a clinical outcomes analysis was performed on the 3 cohorts.

Results

The CoCr was noted to have a statistically significant increase in medial tibial bone loss compared with the other 2 cohorts. The all polyethylene cohort had a statistically significantly higher final Knee Society Score and was associated with the least amount of stress shielding.

Conclusion

The CoCr tray is the most rigid of 3 implants that were compared in this study. Interestingly, this cohort had the highest amount of medial tibial bone loss. In addition, 1 patient in the CoCr cohort had medial soft tissue irritation which was attributed to a prominent medial tibial tray which required revision surgery to mitigate the symptoms.  相似文献   

9.

Background

The burden of revision arthroplasty surgery for infection is rising as the rate of primary arthroplasty surgery increases. Infected arthroplasty rates are now relatively low, but the sheer increase in volume is leading to considerable patient morbidity and significant increases in costs to the health care system. Single-stage revision for infection is one of the several accepted treatment options, but the indications and results are debated. This review aims to clarify the current evidence.

Methods

MEDLINE/PubMed databases were reviewed for studies that looked at single- or one-stage revision knee or hip arthroplasty for infection.

Results

There is increasing evidence that single-stage revision for infection can control infection and with decreased morbidity, mortality, and health care costs compared with a staged approach. However, the indications are still debated. Recently, there has been a determined effort to define an infected arthroplasty in a manner that will allow for standardization of reporting in the literature. The evidence supporting single stage for knee arthroplasty is catching up with the result with hip arthroplasty. High-quality data from randomized controlled trials are now pending.

Conclusion

After the gradual evolution of using the single-stage approach, with the widespread acceptance of this definition, we can now standardize comparisons across the world and move toward a refined definition of the ideal patient population for single-stage arthroplasty revision in both the hip and the knee population.  相似文献   

10.

Background

The ideal fixation for modern tibial components in total knee arthroplasty (TKA) remains controversial with uncertainty on whether cementless implants can yield equivalent outcomes to cemented fixation in early follow-up.

Methods

A series of 70 consecutive cases with reverse hybrid cementless fixation were matched to 70 cemented cases from 2008 to 2015 based on implant design and patient demographics.

Results

Cementless TKA demonstrated greater aseptic loosening (7 vs 0, P = .013) and revision surgery (10 vs 0, P = .001) than cemented fixation within 5 years of follow-up, but with no clinically significant differences in outcome scores.

Conclusion

It remains unclear whether early aseptic loosening in cementless TKA can be reduced with enhanced adjunct fixation and what proportion of early failure justifies the potential lifelong fixation through biologic ingrowth of cementless tibial components.  相似文献   

11.

Background

Associations of lateral/medial knee instability with anterior cruciate ligament (ACL) injury have not been thoroughly investigated. The purposes of this study were to investigate whether lateral/medial knee instability is associated with ACL injury, and to clarify relevant factors for lateral/medial knee instability in ACL-injured knees.

Methods

One hundred and nineteen patients with unilateral ACL-injured knees were included. Lateral/medial knee instability was assessed with varus/valgus stress X-ray examination for both injured and uninjured knees by measuring varus/valgus angle, lateral/medial joint opening, and lateral/medial joint opening index. Manual knee instability tests for ACL were evaluated to investigate associations between lateral/medial knee instability and anterior and/or rotational instabilities. Patients' backgrounds were evaluated to identify relevant factors for lateral/medial knee instability. Damage on the lateral collateral ligament (LCL) on MRI was also evaluated.

Results

All parameters regarding lateral knee instability in injured knees were significantly greater than in uninjured knees. There were significant correlations between lateral knee instability and the Lachman test as well as the pivot shift test. Patients with LCL damage had significantly greater lateral joint opening than those without LCL damage on MRI. Sensitivity of LCL damage on MRI to lateral joint opening was 100%, while its specificity was 36%. No other relevant factors were identified. In medial knee instability, there were also correlations between medial knee instability and the Lachman test/pivot shift test. However, the correlations were weak and other parameters were not significant.

Conclusions

Lateral knee instability was greater in ACL-deficient knees than in uninjured knees. Lateral knee instability was associated with ACL-related instabilities as well as LCL damage on MRI, whereas MRI had low specificity to lateral knee instability. On the other hand, the association of medial knee instability on ACL-related instability was less than that of lateral knee instability.

Levels of evidence

Level IV, case series with no comparison group.  相似文献   

12.

Background

Use of leukocyte esterase (LE) testing of synovial fluid as an adjunct to the infection workup in total joint arthroplasty patients has been advocated. The purpose of this study was to determine the false positive rate of this test.

Methods

Two hundred patients with the diagnosis of degenerative osteoarthritis undergoing a total knee arthroplasty were identified for this study. The knee joint was aspirated under sterile conditions before performing the total knee arthroplasty. The fluid was analyzed with an LE reagent strip.

Results

There were 27 bloody and 17 dry aspirations. One hundred forty-nine patients produced an aspiration that allowed for LE testing. There was 1 positive LE result. The specificity of the LE test was found to be 99.3%.

Conclusion

These data suggest the LE strip as a part of the workup for infection in a native knee should yield few false positive results.  相似文献   

13.

Background

Although venous thromboembolism is one of the leading causes of morbidity after knee arthroplasty, little data exist on the risk of deep venous thrombosis (DVT) after unicompartmental knee arthroplasty (UKA).

Methods

We prospectively enrolled 112 patients undergoing UKA to determine the incidence of DVT utilizing aspirin 325 mg twice a day (BID) for 4 weeks postoperatively as DVT prophylaxis. The data were compared with a recent randomized controlled trial of patients undergoing total knee arthroplasty utilizing aspirin and Lovenox in conjunction with pneumatic compression devices.

Results

One patient (0.9%) had an asymptomatic DVT, and none developed clinical symptoms of either DVT or pulmonary embolus. The incidence of asymptomatic and symptomatic DVT was 0.9% and 0%, respectively.

Conclusion

Our data suggest that 325 mg of aspirin BID for 4 weeks results in a very low risk of DVT for patients undergoing UKA.  相似文献   

14.

Background

Extensor mechanism disruption remains a devastating complication after total knee arthroplasty. The purpose of this study is to describe the outcomes of extensor mechanism allograft (EMA) reconstruction in a large single-center case series.

Methods

Consecutive patients with a previous total knee arthroplasty undergoing extensor mechanism reconstruction using a fresh-frozen EMA tensioned in full extension were identified retrospectively from single-center institutional database (N = 25 patients, 26 knees; mean follow-up 68 months [range 22-113 months]). The primary outcome was initial allograft failure, defined as removal of the allograft or extensor lag >30 degrees at most recent follow-up.

Results

Sixty-nine percent (18/26) of knees had retained their initial allograft reconstruction at their latest follow-up despite reoperation rates of 58% (15/26). A younger age was significantly associated with failure of the initial allograft reconstruction. Knee Society Scores increased from 101 (38 standard deviation [SD]) to 116 (40 SD) at most recent follow-up for the group as a whole (P = .4). Patients undergoing a reoperation for any cause had lower Knee Society Scores (101 [SD 38] vs 138 [SD 32], respectively; P = .04) at most recent follow-up.

Conclusion

EMA reconstruction shows adequate overall intermediate-term survival; however, reoperation rates were high and associated with worse functional outcomes.  相似文献   

15.

Background

Periprosthetic fracture following total hip arthroplasty is a significant problem faced by hip surgeons, and its management in elderly patients remains a considerable challenge.

Methods

We retrospectively reviewed 28 Vancouver B2 and B3 periprosthetic femoral fractures (PFF) treated with revision of the femoral stems by distally locked, hydroxyapatite-coated uncemented stems (Cannulok). Patients were aged 75 years or older at the time of surgery.

Results

The mean follow-up was 44.6 months (range, 24-102). The mean postoperative Oxford hip score was 30.1 (range, 10-46). The rate of fracture union was 95.8%, and the survivorship of the stem was 100% at the end of follow-up.

Conclusion

The management of PFF in elderly is associated with increased postoperative morbidity and mortality. The use of a distally locked, hydroxyapatite-coated femoral stem is a valid option for the treatment of PFF to achieve fracture union with a low rate of revision.  相似文献   

16.

Background

Radiographs are routinely used to evaluate patients postoperatively after total knee arthroplasty, but no evidence-based guidelines exist regarding their use. The purpose of this study is to quantify the use of radiographs within 2 years of primary total knee arthroplasty by one surgeon and to determine if routine studies in asymptomatic patients altered patient management.

Methods

Patients undergoing consecutive primary total knee arthroplasties between 2008 and 2010 were identified. Patients undergoing revision or additional simultaneous procedures or those with less than 6 months of radiographic follow-up were excluded. Operative and clinic notes, radiographs, and radiology reports were reviewed.

Results

A total of 263 patients were identified; each patient had an average of 13.5 ± 3.8 individual radiographs obtained in 6.5 ± 1.7 series. Twelve radiographic series were noted to have abnormal findings by either the attending surgeon or by radiology report. Three of these patients underwent reoperation directly related to the findings; 2 for deep infections and 1 for extensor mechanism disruption. All 3 patients had reported abnormal symptoms when their films were obtained. The remaining 9 abnormal radiographic findings included focal lucencies or osteolysis, asymmetric spacer wear, a healing stress fracture, an inferior patellar avulsion fracture, and heterotopic ossification. No patient had symptoms attributable to these findings when the radiographs were obtained, and in no case was the management altered based on these finding.

Conclusion

This study suggests that the observed frequency of routine postoperative radiographs in asymptomatic patients may not be necessary in the first 2 years after primary total knee arthroplasty.  相似文献   

17.

Background

The purpose of our prospective, randomized, long-term investigation is to compare the aseptic loosening rate of the femoral component of the total knee prosthesis and clinical and radiographic results of high-flexion posterior cruciate-substituting knee prosthesis or standard posterior cruciate-substituting knee prosthesis in the same patients.

Methods

There were 960 patients (mean age 71.3 years). The mean follow-up period was 13.2 years (range 10-14). The patients were assessed clinically and radiographically with rating systems of the Knee Society. Furthermore, Western Ontario and McMaster Universities Osteoarthritis questionnaire and ranges of knee motion were determined in both groups.

Results

In the high-flexion knee group, 2 knees (0.2%) had aseptic loosening of both femoral and tibial components. In the standard knee group, 2 knees (0.2%) had aseptic loosening of the femoral component only. The mean postoperative knee scores (97 vs 97 points), Western Ontario and McMaster Universities Osteoarthritis scores (19 vs 19 points), and range of knee motion (128° vs 129°) were not significantly different between the 2 groups. Two knees (0.2%) in the high-flexion knee group underwent a revision of both femoral and tibial components and 2 knees (0.2%) in the standard knee group had a revision of the femoral component only.

Conclusion

After a mean of 13.2 years of follow-up, this study did not show increased incidence of femoral component loosening in the high-flexion knee group. Furthermore, we found no significant differences between the 2 groups with regard to clinical or radiographic parameters or range of knee motion.  相似文献   

18.

Purpose

This study aimed to clarify the influence of the posterior condylar offset (PCO) on intraoperative soft tissue balance including the joint component gap and varus ligament balance measured by an offset-type tensor during posterior-stabilized (PS) total knee arthroplasty (TKA).

Methods

In this study, 35 patients with osteoarthritis of the knee underwent PS TKA. Intraoperative soft tissue balance including the joint component gap and varus/valgus ligament balance were assessed at 0°, 10°, 45°, 90°, and 135° of flexion with an offset-type tensor that could be used with the femoral component placement and patellofemoral joint reduction. The correlations between the postoperative PCO and the intraoperative soft tissue balance parameters were assessed using simple regression analysis.

Results

The joint component gap at 0° extension was inversely correlated with the PCO (R = ?0.41, p < 0.05). The joint component gap of 10°–0° was positively correlated with the PCO (R = 0.35, p < 0.05). No other soft tissue balance parameters were correlated with the PCO.

Conclusions

A larger PCO was confirmed to reduce joint component gap in extension but not always in flexion in PS TKA.  相似文献   

19.

Background

Accelerometer-based, portable navigation devices have been introduced as a less invasive and simpler technique to perform navigated surgical implantation of knee prostheses. They have been postulated to have better accuracy than conventional instruments in restoration of alignment in total knee arthroplasty.

Methods

A total of 190 patients were enrolled in this prospective, randomized controlled trial and underwent total knee arthroplasty using either the KneeAlign or conventional guides. Multiplanar alignment was evaluated with a CT imaging protocol.

Results

A total of 86.5% of portable navigation device and 82.2% of conventional group had a postoperative hip–knee angle within 3° of neutral alignment (P = .54). There was no significant difference between the 2 groups for component coronal and sagittal plane alignment. Portable navigation device did not significantly increase the time to perform the surgery.

Conclusion

Portable navigation device demonstrates accurate restoration of alignment; however, there was no statistically significant difference when compared with conventional guides.  相似文献   

20.

Background

Postoperative anemia is frequent after revision of total knee arthroplasty (TKA) with reported transfusion rates up to 83%. Despite increased efforts of reducing blood loss and enhancing fast recovery within the fast-track setup, a considerable transfusion rate is still evident. The aim of this study was therefore to evaluate the effect of a bipolar sealer on blood loss and transfusion in revision TKA.

Methods

In this single-center prospective cohort study with retrospective controls, 51 patients were enrolled in a fast-track setup for revision TKA without the use of a tourniquet. Twenty-five prospectively enrolled patients received treatment with both a bipolar sealer and electrocautery, whereas 26 patients had received treatment with a conventional electrocautery only in the retrospective group.

Results

No significant differences were found neither for calculated blood loss, with 1397 (standard deviation, ± 452) mL in the bipolar sealer group vs 1452 (SD, ± 530) mL in the control group (P = .66), nor for blood transfusion rates of 53% and 46% (P = .89), respectively. Four controls were readmitted within 90 days follow-up.

Conclusion

The use of a bipolar sealer in a TKA revision setting without the use of a tourniquet did not reduce blood loss or blood transfusion rates.  相似文献   

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