Knee biomechanics and contralateral knee osteoarthritis progression after total knee arthroplasty

BackgroundDespite the success rate of Total Knee Arthroplasty (TKA), many patients undergo contralateral TKA. It is possible that altered gait mechanics after unilateral TKA play a role in the progression of contralateral OA progression.Research questionThe purpose of this study was to identify biomechanical predictors of radiographic OA progression in the contralateral (non-surgical) knee after unilateral (primary/initial) TKA. In addition, this study quantified for patients who had contralateral OA progression.MethodsBiomechanical outcomes were collected 6–24 months after unilateral primary TKA and were used to predict changes in contralateral OA severity at follow-up. Participants were divided into “Progressor” and “Non-Progressor” groups based on changes in Kellgren-Lawrence (KL) OA grade and Joint Space Width (JSW) between baseline and follow-up testing sessions. Biomechanical factors during walking were peak knee adduction moment, knee flexion/extension excursions, knee angle at initial foot contact, and peak knee flexion/extension. Multiple independent t-tests were used to examine the magnitude of differences in biomechanical variables between the groups. Logistic regression was used to examine the association between the biomechanical predictors and change in KL scores and JSW.ResultsThe mean time between surgery and follow-up x-rays was 8.8 (2.4) years. Of 40 participants, 62.5–78% had contralateral radiographic knee OA progression by follow-up. There were no significant differences in the biomechanical variables between groups. For the regression analysis, none of the biomechanical variables were found to be predictors for contralateral OA progression.SignificanceAlthough abnormal biomechanics are known risk factors for primary knee OA, it is possible that the mechanisms that result in OA progression of the contralateral limb are different than primary knee OA progression. Future work should evaluate other objective measures of OA progression and determine if cumulative measures of joint loading are related to OA worsening.     

Anterior cruciate ligament reconstruction after unicompartmental knee arthroplasty

Purpose  

ACL deficiency may cause abnormal knee kinematics and is associated with a tenfold increase in surgical failures after unicompartmental knee arthroplasty, such as aseptic loosening of the tibial compartment and medial bearing instability. The current investigators hypothesized that in a knee with UKA, single-bundle ACL reconstruction would restore tibiofemoral translation to levels similar to those of the intact ACL.     

Pain after knee arthroplasty: an unresolved issue

Purpose

Despite the recent advances in the understanding of pain mechanisms and the introduction of new drugs and new techniques in the postoperative management, pain after total knee arthroplasty (TKA) is still an unresolved issue. It affects the quality of life and rehabilitation of an important percentage of patients undergoing TKA. The aim of this narrative review was to give an overview on pain mechanisms and multimodal pain management.

Methods

A review of all peer-reviewed articles on pain after knee arthroplasty was performed by two reviewers. Recent articles on incisional pain mechanisms were included because of their importance in the understanding of postsurgical pain. Search was performed in Pubmed, Cochrane and Google Scholar data bases.

Results

Postsurgical pain mechanisms are based on both local and systemic inflammatory reactions. Peri-operative pain management starts with the anaesthetic technique and resides on a multimodal analgesia regimen. New concepts, drugs and techniques have shown their efficacy in reducing the severity of acute postoperative pain and the risk of developing chronic pain after TKA.

Conclusion

This narrative review offers a clear overview of pain mechanism after knee arthroplasty and an understanding on how multimodal pain management can reduce the intensity and duration of pain after knee arthroplasty.

Level of evidence

IV.     

Knee flexion after total knee arthroplasty reduces blood loss

Purpose

Extensive blood loss after total knee arthroplasty (TKA) may be a potential problem since it leads to anaemia, increased need for transfusion and prolonged hospitalization. Aim of this study was to investigate the effects of postoperative knee flexion after TKA on blood loss and the need for transfusion.

Methods

One hundred consecutive patients undergoing primary TKA from 2012 to 2013 were randomizely divided into two groups. In one group, the knee was extended for the first 6 h after surgery, whereas in the other was flexed at 90° for the same time. Two doses of endovenous tranexamic acid were administered in all subjects. Patients were homogeneous for all the possible confounding factors.

Results

Calculated blood loss was 846 ± 197 (ml) in the flexion group and 1,242 ± 228 (ml) in the extension group (p < 0.05). Drop of haemoglobin levels at 24 h in the study group and the control group was 1.9 ± 0.8 (g/dl) and 3.0 ± 0.5 (g/dl), respectively (p < 0.01). Drop of haematocrit at 24 h was 4.5 ± 0.2 (%) in the flexion group and 6.7 ± 0.3 (%) in the extension group (p < 0.05). Blood transfusion was necessary in 5 patients in the control group and was not necessary in any patient of the study group. Average knee flexion at day 7 was 105° ± 4° in the flexion group and 98° ± 7° in the extension group.

Conclusion

Knee flexion at 90° after TKA, associated with the intraoperative use of tranexamic, acid is an effective method to reduce blood loss and the need for blood transfusion. The routine use of the present protocol is effective in reducing social costs and length of hospitalization of TKA procedures.

Level of evidence

Prospective comparative study, Level I.     

Knee arthroplasty for spontaneous osteonecrosis of the knee: unicompartimental vs bicompartimental knee arthroplasty

Spontaneous osteonecrosis of the knee (SON) is an osteonecrosis that mainly affects the medial femoral condyle. In endstage SON, knee arthroplasty is the therapy of choice. Because of the unicompartimental nature of the knee, unicondylar knee arthroplasty is considered an ideal implant for treatment of this condition. The purpose of this study was to prove that the long-term results of unicondylar implants are better than the results of bicondylar implants for the treatment of SON. All patients treated for SON between 1984 and 2000 have been recorded. Two groups were formed according to the implant used. In all patients the preoperative radiograph was analyzed according to stage and size of the osteonecrotic lesion and the osteoarthritic changes. Postoperatively, the Knee Society Score and the radiograph were recorded. Thirty-nine patients were included in this study, of which 23 patients were treated by a unicondylar implant and 16 by a bicondylar implant. On a short-term basis, unicondylar implants had better clinical results; however, on a long-term basis bicondylar implants were better. In comparison, only unicondylar implants had to be revised. Radiolucency lines were mainly observed in patients with unicondylar impants and large areas of osteonecrosis. Our long-term results suggest that patients with SON are better treated by bicondylar implants. The reasons for the higher failure rate for unicondylar implants are poor bone stock and secondary arthritic changes.     

Anterior Knee Pain in a 29-Year-Old Woman

A group of experts from the University of California, San Diego, School of Medicine, met to discuss a case. This case conference is part of a series featuring a variety of sports medicine topics.     

Translation and validation of the Dutch version of the International Knee Documentation Committee Subjective Knee Form

BACKGROUND: For knee-related surgery, there is a great demand for internationally useable subjective scoring systems. Before such measurements can be used, they should be translated and validated for the population they are used on. For the Dutch population, only the Western Ontario and McMaster Universities Osteoarthritis Index and Oxford 12 Questionnaire have been validated. However, these scores can only be used regarding osteoarthritis of the knee. In 2001, the International Knee Documentation Committee presented the Subjective Knee Form, which is a knee-specific rather than a disease-specific questionnaire. STUDY DESIGN: Cohort study (diagnosis/symptom prevalence); Level of evidence, 2. METHODS: The authors describe the translation procedure and validation of the Dutch Subjective Knee Form. After a forward-backward translation protocol, the reliability, validity, and content validity were tested. The responses of 145 consecutive knee patients on 2 questionnaires containing the Short Form-36, Western Ontario and McMaster Universities Osteoarthritis Index, Oxford 12 Questionnaire score, a visual analog scale, and the Dutch International Knee Documentation Committee Subjective Knee Form were used. Reliability was tested by measuring the test-retest reliability and internal consistency. Validity was tested by correlating the questionnaire to the other outcome measurements, and content validity was tested by measuring the floor and ceiling effects. RESULTS: The reliability proved excellent with an intraclass coefficient of 0.96 for test-retest. Internal consistency was strong (Cronbach alpha, .92). The construct, convergent, and divergent validities were good. The content validity was good; no floor or ceiling effect occurred. CONCLUSION: The validation procedure shows that the Dutch International Knee Documentation Committee Subjective Knee Form is an excellent evaluation instrument for Dutch patients with knee-related injuries.     

Toe-out angle changes after total knee arthroplasty in patients with varus knee osteoarthritis

Purpose

Toeing-out is a commonly proposed kinematic variable that has been suggested to reduce external knee adduction moment. Analyses of the toe-out angle after total knee arthroplasty (TKA) are useful for obtaining a proper understanding of the abnormal gait caused by varus knee osteoarthritis (OA), as well as performing rehabilitation after arthroplasty. Changes in the toe-out angle after arthroplasty have not yet been defined or analysed.

Methods

The study population consisted of 32 knees in 32 patients with varus knee OA who underwent TKA. The femorotibial angle was evaluated on standing anteroposterior radiographs before and after arthroplasty. The subjects underwent three-dimensional motion capture analyses to measure gait parameters (walking speed, cadence, stride length, step length, step width and the relative length of the single-limb support (SLS) percentage of one gait cycle) and the maximal hip adduction angle in the stance phase, the trunk lean angle in the coronal plane and the toe-out angle before and 4 weeks after arthroplasty.

Results

The femorotibial angle on the side of arthroplasty improved after surgery. Among the measured gait parameters, only the SLS percentage increased significantly. The hip adduction angle and toe-out angle on the side of arthroplasty increased significantly after surgery.

Conclusions

The knee alignment and hip adduction angle in the coronal plane and SLS phase were normalized after arthroplasty. The increase in the toe-out angle after arthroplasty may be attributable to the restoration of a normal knee alignment. These findings contribute to obtaining a proper understanding of the abnormal gait caused by varus knee OA and are useful for orthopaedic surgeons and rehabilitation therapists when treating patients after arthroplasty.

Level of evidence

Prospective study, Level II.     

Arthrodesis of the knee after failed infected total knee arthroplasty

Infection after total knee arthroplasty (TKA) can be a challenging and difficult problem to treat. In selected patients, knee arthrodesis is a well-recognized salvage procedure after infected TKA. The authors retrospectively reviewed their experience with this treatment option, presenting 20 patients (8 women, 12 men), performed between 1990 and 2002. The average age was 67 years (range: 47–81 years) and the mean number of previous surgical procedures was 6 (range: 4–11 procedures). There were multiple indications for knee arthrodesis, including extensive bone or soft tissue loss, poor bone stock, and recurring infections. One-stage fusion was done in 7 knees while, on the other 13, arthrodesis was performed as two-stage fusions. The average clinical follow-up was 4.5 years (range: 2–11 years). 18 of the 20 patients were interviewed and graded using the Visual Analogue Scale (VAS) for pain, the Short Form-36 Health Survey (SF-36), and the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire that has knee-related quality of life items. According to the VAS, the mean intensity was 3.4 points. 6 (33%) of the patients had no difficulty with the knee and 9 (50%) of them had mild or moderate difficulty. The SF-36 scores were similar to those for normative data for patients after TKA, with only the social functioning, role emotional, and physical functioning scores being lower and the role physical and social functioning scores being higher. Three of 20 fusions failed, whereas two knees became non-infected non-unions. In one, the knee infection persisted and required above-knee amputation. The two-stage arthrodesis gave the most predictable rate of fusion. Persistent infection and extensive bone stock losses led to failure even under the best circumstances. In our opinion, arthrodesis of the knee is a satisfactory salvage procedure following a failed TKA, and can provide reliable expectation for a stable, painless extremity for high-functioning patients who are able to walk.     

Clinical and functional results after the rehabilitation period in minimally-invasive unicondylar knee arthroplasty patients

The objective of the present study was to analyze the clinical and functional outcome after minimally-invasive implantation of a Repicci-type unicompartmental sledge prosthesis . In 29 patients with primary unicompartmental knee osteoarthritis, 29 replacements of the medial compartment and four of the lateral compartment were performed using the minimally-invasive technique with the metal-backed and the all-polyethylene versions of the Repicci sledge prosthesis. Electromyography (EMG) of standardized locations was measured with the MyoSystem 2000 and analyzed with Myoresearch software. Gait analysis was performed with a six-camera motion analysis system and force platforms. Established clinical and quality of life (SF-36) scores were used to compare patients with 11 healthy age-matched individuals. The Repicci sledge prosthesis led postoperatively to functional results that were in the range of healthy joints, and superior to sledge prostheses of a different design. Gait and balance parameters were comparable to the control group, whilst electromyographically lower amplitudes were found in the patients than the controls and in the operated legs as compared to the non-operated legs. Many parameters of quality of life and activity were comparable to age-matched healthy individuals, and quality of life was superior to total knee replacement. When implanted using a minimally-invasive technique and with suitable patient selection, the Repicci sledge led to functional results comparable to those of healthy joints and gait parameters comparable to those of healthy individuals. The level of evidence is Level III, retrospective cohort study.     

Depressed patients feel more pain in the short term after total knee arthroplasty

Purpose

The hypothesis of this study was that depressive patients feel more pain in the immediate TKA postoperative period in comparison with non-depressed patients.

Methods

The diagnosis of depression was made with the Geriatric Depression Scale Short Form. The Visual Analogic Score (VAS) was registered each 8 h during the first 3 days. The mean and maximum VAS and the number of analgesic rescues required in this period were calculated in 803 consecutive TKAs. The Knee Society Score (KSS), the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC), and the Short Form-36 (SF-36) scores were obtained preoperatively and at the 1-year follow-up.

Results

Forty-eight (6%) of these patients were considered depressed. The results obtained in the depressed patients and non-depressed were, respectively, mean VAS (2.0 vs 1.0, p?=?0.00), maximum VAS (5.3 vs 1.6, p?=?0.00), and number of rescues needed (4.4 vs 1.8, p?=?0.00). Although depressed patients scored worse in the functional and quality of life scores in the preoperative period, the improvement obtained (1-year outcomes minus preoperative outcomes) in the different scores was similar in both groups with the exception of the mental domain of the SF-36, which improved further in depressed patients (p?=?0.00).

Conclusion

Depressed patients feel more pain in the immediate postoperative period. However, the improvement obtained in functional and referred quality of life scores is similar to non-depressed patients.

Level of evidence

II.

     

Expectation, satisfaction and clinical outcome of patients after total knee arthroplasty

Purpose  

There is a well-known difference between patients expectation, satisfaction and the measured clinical outcome in total knee arthroplasty (TKA). It has been hypothesized that higher expectation prior to surgery and higher satisfaction will show better clinical outcome according to well-established scoring systems, frequently used for assessment after TKA.     

Anterior knee laxity in skiers before and after racing

Nineteen top-level local skiers were measured for anterior knee laxity using a commercial knee laxity testing device, the Medmetric knee arthrometer model KT-1000. There were 7 women and 12 men; their average age was 27.1 years, with the ages ranging from 22 to 36 years. Six recreational skiers, 4 women and 2 men (average age 26.6 years), were measured before and after two periods of free skiing for 2 h each for control. According to statistical analysis, anterior knee laxity significantly increased after racing activity. The post-race measurement of anterior laxities showed that 2 of the skiers had a ruptured anterior cruciate ligament (ACL). The histological findings regarding the ruptured ACL revealed waving of the collagen fiber and remodeled ACL collagen fiber. We suspect that the excessive stress on the knee caused by quadriceps contraction may weaken the ligamentous tensile property.     

全膝关节置换术中髌骨置换对骨性关节炎患者早期疗效及膝前痛的影响

目的：探讨全膝关节置换术中是否进行髌骨置换对骨性关节炎患者的临床疗效及术后疼痛的影响。方法笔者采用随机数字表法将骨科2011年5月～2013年7月收治的93例行人工全膝关节置换术患者分为髌骨置换组43例和未置换组50例,比较两组患者治疗前与治疗后不同时间的相关指标变化差异。结果术前髌骨置换组与非置换组的膝关节KSS（美国膝关节协会）评分、Feller评分差异不显著（ P＞0．05）;术后第3、6、12个月髌骨置换组膝关节KSS评分、Feller评分显著高于非置换组（P＜0．05）;术前髌骨置换组与非置换组的膝关节视觉模拟评分（VAS）差异不显著（P＞0．05）;术后第3、6、12个月髌骨置换组膝关节VAS评分显著低于非置换组（P＜0．05）;两组患者术前、术后的胫股角,髌韧带比值,关节活动度ROM屈、伸值在两组间比较差异均不显著（ P＞0．05）;术后第12个月两组患者的胫股角、髌韧带比值,关节活动度ROM屈、伸值较治疗前均显著好转（ P＜0．05）。结论全膝关节置换术中进行髌骨置换对改善膝关节功能评分、髌骨评分、术后疼痛评分均有显著的效果。     

加速康复外科理念在膝关节置换术围术期应用

目的评价加速康复(ERAS)外科理念在膝关节置换术围术期的应用疗效。方法收集2015年1月至2016年1月收治的因膝关节骨性关节炎行膝关节置换术的82例患者,随机分为ERAS组(n=40)和常规组(n=42),比较两组围手术期疗效。结果患者82例随访1个月。所有患者切口均一期愈合,术后12 d拆线。ERAS组术中出血量、输血量均明显少于常规组,差异有统计学意义(P<0.05)。两组手术时间比较,差异无统计学意义(P>0.05)。ERAS组术后住院(8.0±3.4)d,明显低于常规组的(11.5±3.6)d,两组平均住院日比较,差异有统计学意义(P<0.05)。两组均未发生切口并发症。两组深静脉血栓、泌尿系统感染并发症发生率比较,差异无统计学意义(P>0.05)。比较术后12 d和术后1个月的膝关节KSS评分,ERAS组膝关节KSS评分优于常规组,差异有统计学意义(P<0.05)。结论 ERAS外科理论在膝关节置换围术期的应用能明显缩短术后住院时间和住院费用,可以促进患者膝关节功能的康复,值得推广和应用。     

胫骨骨折患者髌上与髌下入路髓内钉内固定术后膝前疼痛情况对比分析

目的对比观察胫骨骨折患者髌上入路与髌下入路髓内钉内固定术后的膝前疼痛程度。方法选取2018年12月至2020年2月郑州人民医院收治的98例拟行髓内钉内固定术治疗的胫骨骨折患者作为研究对象,按照随机数表法将其随机分为观察组(49例)和对照组(49例)。观察组患者采用髌上入路髓内钉内固定术治疗,对照组患者采用髌下入路髓内钉内固定术治疗,对比观察两组患者阿伯丁负重试验-膝关节(AWT-K)评分和视觉模拟评分法(VAS)评分。结果术后6个月,观察组患者在30、45、60s时的AWT-K评分均明显高于对照组(t=2.047、4.754、7.000,P=0.043、P<0.001、P<0.001);术后12个月,观察组患者在15、30、45、60 s时的AWT-K评分均明显高于对照组(t=4.030、4.556、9.134、11.050,P均<0.001);术后6、12个月,观察组患者VAS评分均明显低于对照组(t=4.567、12.600,P均<0.001)。结论与髌下入路髓内钉内固定术相比,髌上入路髓内钉内固定术可明显减轻胫骨骨折患者术后膝前疼痛程度,提高膝关节承重能力。     

Changes in patellar alignment after total knee arthroplasty

Although the results of total knee arthroplasty continue to improve, problems related to the patellofemoral joint remain significant. This study examined the factors affecting patellar alignment after total knee arthroplasty and subsequent changes in 56 knees during a postoperative period of 5.3 years. None of the knees examined displayed any clinical complications of the patellofemoral joint; no revision surgeries were necessary, with acceptable patellar alignment on average. The patellar resection angle had a strong influence on patellar alignment. Thinning of the patellar remnant on the medial side can increase postoperative lateral tilt, which leads to a need for lateral retinacular release. Although the changes in patellar alignment were minimal, the tendency that postoperative varus alignment resulted in patellar lateral tilt was observed. As postoperative femorotibial misalignment can lead to patellofemoral problems after total knee arthroplasty, surgeons need to pay scrupulous attention to femorotibial alignment and proper patellar preparation to decrease patellofemoral complications.