The radiographic predictors of symptom severity in advanced knee osteoarthritis with varus deformity

High tibial osteotomy is equally effective for varus malaligned knees with either virgin or wrecked medial meniscus: An age and gender-matched secondary analysis of a Francophone Arthroscopy Society Symposium

INTRODUCTION

Despite the growing concept of meniscal preservation, partial meniscectomy could be the definitive procedure in specific scenarios. And total meniscectomy was once before a frequent procedure, with current sequelae of degenerate knees. High tibial osteotomy (HTO) is an effective treatment for patients suffering from unicompartmental degenerative changes, and substantial deformities. However, it is yet to be answered, whether HTO is similarly effective in both post-meniscectomy knees and knees with not previously operated meniscus.

HYPOTHESIS

Outcomes of HTO is similar with or without previous history of total or subtotal meniscectomy.

METHODS

This study compared the clinical and radiological outcomes of 41 patients who received HTO and had no previous history of surgery in the ipsilateral knee (group I), and 41 age, and gender-matched patients who had meniscectomy surgery in the ipsilateral knee (group II). Preoperatively and postoperatively, all patients were clinically evaluated; the visual analogue scale scores, Tegner activity score, and the Western Ontario and Macmaster University scores were reported. Radiographically, osteoarthritis grade and pre- and postoperative parameters were reported, including hip-knee-ankle angle, femoral mechanical angle, medial proximal tibial angle, joint line convergence angle, proximal posterior tibial angle, and limb length discrepancy. Perioperative details and complications were reported.

RESULTS

A total of 82 patients were included; group I (n=41) and group II (n=41). The mean age was 51.18±8.64 (27-68) and 90.24% were male. The duration since the onset of symptoms was longer in group II vs. group I, 43.34±41.03 versus 38.07±36.11months respectively. No significant differences in the clinical evaluation between the two groups with a greater proportion of patients demonstrating moderate degenerative changes. Similar preoperative and postoperative radiographic parameters were reported, in group I, Δ HKA was 7.19±4.14 versus 7.65±3.16 in group II. Preoperative pain VAS scores were slightly higher in group II vs. group I, 79.23±26.35 vs. 76.31±24.45, respectively. However, postoperatively, the pain scores significantly improved in group I vs. group II, 22.84±3.65 vs. 41.69±17.33, respectively. Tegner activity scores and WOMAC scores were comparable between both groups preoperatively and postoperatively. Only the WOMAC function scores were better in group I when compared to group II, 26.13±25.84 versus 20.01±17.98. All patients returned to work at an average of 0.82±0.38months.

CONCLUSION

Knee preservation with high tibial osteotomy is equally effective in managing unicompartmental degenerative changes in varus malaligned knees with either no previous history of meniscal surgeries or where a meniscal sacrifice was inevitable, either with subtotal or total meniscectomy.

LEVEL OF EVIDENCE

III, retrospective case-control study.

The Effect of Lateral Wedge Insole on Gait Variability Assessed Using Wearable Sensors in Patients with Medial Compartment Knee Osteoarthritis

Background

Lateral thrust seen in people with medial compartment knee osteoarthritis can cause dynamic knee instability and poor postural control during gait cycles. A lateral wedge insole can reduce the lateral thrust and may have a favorable effect on gait variability, which in turn may indicate gait instability improves. The aim of this study was to investigate the effect of lateral wedge insole on gait variability in knee osteoarthritis patients.

Method

We involved 15 symptomatic knee osteoarthritis patients who were provided with lateral wedge insole and 13 healthy asymptomatic volunteers as the control group. The gait variability was evaluated as the coefficient of variation of stride, stance, and swing duration based on acceleration monitoring using a wearable sensor. The lateral thrust was estimated as the lateral acceleration peak on the shank sensor. These measurements were performed without lateral wedge insole (baseline), immediately with lateral wedge insole (T0) at the initial office visit and one month after intervention (T1).

Result

Our data showed that the stance duration coefficient of variation and lateral thrust at T1 in the knee osteoarthritis group, were significantly decreased compared to the baseline values and these values were identical to those in the control group.

Conclusion

The lateral wedge insole reduces dynamic knee instability and could improve gait variability in medial compartment knee osteoarthritis.

Coronal tibiofemoral subluxation in patients with osteoarthritis was corrected after total knee arthroplasty

The objective of this study was to investigate the effect of preoperative coronal tibiofemoral subluxation (CTFS) on postoperative mechanical alignment in patients undergoing total knee arthroplasty (TKA) for primary knee osteoarthritis (OA) and to investigate whether TKA can correct preoperative CTFS. We hypothesized that TKA would correct CTFS in patients with knee OA. A retrospective analysis of 102 patients with knee OA who underwent TKA was performed. The preoperative and postoperative CTFS and mechanical alignment were measured and compared. At the same time, the baseline values of CTFS and mechanical alignment in "normal" patients were measured and compared with those in the operation group. Eighty patients were eventually enrolled in the study. Mechanical alignment was corrected from 7.3 ± 5.2°, preoperatively, to 1.6 ± 2.3° postoperatively, while the tibiofemoral subluxation was corrected from 5.3 ± 2.6 mm, preoperatively, to 2.3 ± 2.7 mm postoperatively. There was no significant correlation between preoperative CTFS and gender (r = 0.03), BMI (r = -0.09), age (r = 0.05), or preoperative mechanical alignment (r = 0.09). In addition, there was no correlation between the degree of correction of CTFS and the degree of correction of overall mechanical alignment (r = 0.14). The difference between the value for CTFS in the "normal" patients and the preoperative value for arthritis cohorts were statistically significant (P = .004). However, no significant difference was appreciated between the value for CTFS in the "normal" patients and the postoperative value for TKA cohorts (P = .25). Preoperative CTFS does not affect postoperative mechanical alignment. Excellent TKA can correct preoperative CTFS in OA patients to reduce prosthesis wear and improve postoperative patient satisfaction.

Influence of preoperative coronal and sagittal tibiofemoral subluxation in knee osteoarthritis on the outcome of primary total knee arthroplasty

BACKGROUND

The effect of osteoarthritis (OA) with tibiofemoral (TF) subluxation on patients undergoing total knee arthroplasty (TKA) has been less studied, and there have been no studies on sagittal knee subluxation which is a component of a three-dimensional problem. We aim to analyze the influence of preoperative coronal and sagittal knee subluxation with OA on other radiological parameters and the functional outcome in patients undergoing TKA.

METHODS

We retrospectively reviewed the 179-consecutive primary TKA in 151 patients from January 2017 to June 2017. The radiological parameters analyzed were the mechanical tibiofemoral angle (HKA), joint line congruence angle (JLCA) and coronal tibiofemoral (CTF) subluxation in long leg films. In the lateral view, posterior tibial slope, the settlement area of the femur over the tibia and the sagittal tibiofemoral (STF) subluxation were calculated. Preoperative and postoperative knee society and knee society functional scores were documented. Multivariate regression analysis was done to determine the association of preoperative radiological parameters with coronal and sagittal TF subluxation.

RESULTS

The average follow-up was 31 months (2.6 years). 102 knees (57%) had CTF subluxation (< 5 mm) within normal range, and 77 knees (43%) had CTF subluxation. There was a direct correlation between the magnitude of CTF subluxation and poor preoperative functional scores compared with the non-subluxation group (p < 0.05). CTF subluxation was not associated with the magnitude of varus deformity as it is correlated more with mild deformity (odds ratio [OR] 10.07, 95% confidence interval [CI] 3.47-29.25) than with moderate and severe varus deformity. The degree of the joint line convergence angle was positively correlated with the amount of CTF subluxation (p = 0.003). STF subluxation had a significant correlation with the posterior slope (p < 0.001), but not with the magnitude of varus deformity (p = 0.26).

CONCLUSION

Coronal and sagittal tibiofemoral subluxation had a significant association with poor preoperative clinical scores. The degree of CTF subluxation reduces with the increasing magnitude of varus deformity and JLCA. STF subluxation was associated with the posterior tibial slope. Patients who underwent posterior stabilized TKA had excellent clinical outcomes irrespective of preoperative knee subluxation.

Correctability of the knee joint observed under a stressed state

BACKGROUND

Well-balanced postoperative knee joints are often based on subjective 'feel' of experienced surgeons rather than quantifiable references. Most alignment strategies continue to reference the bone despite the complexity in anatomical variations and presence of deformity. Categorical prescription of a singular alignment philosophy for all patients may not be appropriate. This study aims to characterize coronal alignment correctability in relation to anatomical measures to develop a mechanism for distinguishing patients for whom repeatable strategies are optimal in the form of alternative alignment techniques or advanced soft tissue balancing.

METHODS

A consecutive series of 103 pre-operative knees who underwent primary total knee arthroplasty (TKA) were analysed. Pre-operative supine computer tomography (CT) scans were segmented, with output STL bone models placed against several stressed positions determined by the TELOS SD-900 (METAX, Germany) device. Anatomical analysis using two-dimensional (2D) -3D image registration was performed. Statistical analysis was conducted for variations in anatomical morphology and regression modelling was used to determine the relationship between these measurements and correctability of a patient.

RESULTS

The mean preoperative supine hip-knee-ankle (HKA) angle was 5.1° and 2.3°, lateral distal femoral angle (LDFA) was 2.0° and 3.1°, medial proximal tibial angle (MPTA) was 3.7° and 3.0° varus for male and female, respectively. The mean laxity range was 4.3°. We found 36% of valgus patients and 55% of mild varus patients to be correctable. Supine HKA was a statistically significant predictor for correctability (P < 0.001). A statistically significant correlation between laxity and the HKA (P = 0.01) as well as LDFA angles (P = 0.01) exist for the mild varus cohort.

CONCLUSION

Relationship between HKA angle and the correctability of the knee joint to neutral in patients presenting with mild to moderate varus cannot be consistently predicted using bony anatomy. If there is a desire to avoid ligament release during TKA, careful consideration of both a patient's bony anatomy and soft tissue laxity envelope must be made prior to surgery.

Varus Knee Deformity Classification Based on Degree and Extra- or Intra-Articular Location of Coronal Deformity and Osteoarthritis Grade

BACKGROUND

Medial coronal plane malalignment, also known as varus alignment, is commonly reported in osteoarthritic knees. Although the degree of deformity provides some insight regarding the severity of the disease, it does not always reflect the potential complexity of the surgical treatment.

METHODS

This prospective observational study was conducted by analyzing the radiographs of 100 consecutive knees in patients undergoing total knee arthroplasty. For each knee, coronal alignment, expressed as the hip-knee-ankle angle, was measured on a full-leg standing radiograph and classified in 3 stages. The primary location of the varus deformity was identified as intra-articular and/or extra-articular. Additionally, knees were evaluated to assess for 10 radiographic features of varus deformity and then classified in 3 grades of osteoarthritis severity.

RESULTS

The mean (and standard deviation) preoperative varus deformity was 11° ± 6° of varus (hip-knee-ankle, 169°), as measured on standardized full-leg radiographs. Extra-articular varus deformity was observed in 14% of patients. A higher number of radiographic features of varus severity corresponded with higher degrees of deformity. Varus grade correlated strongly with stage of varus deformity. Twenty-three (100%) of 23 stage-III deformities had grade-C features; however, 13 (48%) of 27 stage-I patients also had grade-C disease.

CONCLUSIONS

One of every 7 osteoarthritis patients with varus deformity had an extra-articular deformity, and 1 of 2 of these patients had severe intra-articular disease (grade C) despite limited coronal deformity (stage I). These findings reconfirm the need for individual deformity analysis that accounts for the degree, location, and severity of the varus deformity. This insight may help to formulate an algorithmic treatment approach specific to the epiphyseal knee anatomy of the patient and according to the surgical preferences of the surgeon.

CLINICAL RELEVANCE

Knee surgeons tend to consider knees with higher degrees of coronal deformity as more technically difficult, but the present study shows that knees with less deformity can still present with severe grades of osteoarthritis inside the knee, leading to more challenging joint reconstruction.

Tibiofemoral subluxation in the coronal plane does not affect WOMAC and KOOS after total knee arthroplasty

PURPOSE

To investigate the effect of preoperative coronal tibiofemoral subluxation (CTFS) on functional outcome, prosthesis type, insert thickness and revision rates in patients who underwent total knee arthroplasty (TKA).

METHODS

A total of 224 knees of 186 patients were included. Patients were divided into two groups as either with (Group 1, 114 knees of 86 patients) or without (Group 2, 124 knees of 100 patients) coronal lateral tibiofemoral subluxation. The mean follow-up period was 71.3 ± 7.3 (range 60-84) months in group 1 and 69.4 ± 6.6 (range 61-79) months in group 2 (n.s.). Coronal tibiofemoral subluxation degree was measured in degrees on standing anteroposterior knee radiographs. Group 1 was divided into three subgroups according to amount of subluxation (< 5 mm, 6-10 mm and > 10 mm). Functional outcome was evaluated using the Western Ontario and McMaster Osteoarthritis Index (WOMAC) score and Knee Injury and Osteoarthritis Outcome Score (KOOS) preoperatively and at the last follow-up visit. Prosthesis type, insert thickness and revision rates were compared between the two groups.

RESULTS

There were no significant differences between the two groups regarding patient demographics, prosthesis type, and revision rates (n.s.). The insert thickness was found significantly higher in group 1 (p < 0.001). The preoperative and postoperative WOMAC and KOOS scores were found no significantly different between the two groups (n.s.). Among subluxation (+) subgroups, there was no significant difference in functional outcome scores and revision rates (n.s.). However, prosthesis type and insert thickness were significantly associated with the amount of subluxation (p = 0.009 and p = 0.001, respectively). There was no significant correlation between the degree of lower extremity deformity and coronal tibiofemoral amount of subluxation (n.s.).

CONCLUSION

Preoperative CTFS does not adversely affect the WOMAC score, KOOS and revision rates after TKA. In the clinical practice, surgeons should be aware of the need for a posterior cruciate stabilizing prosthesis and a thicker insert in the presence of CTFS, especially with subluxation greater than 10 mm and to consider a spared bony resection on the tibia in patients suffering from CTFS.

LEVEL OF EVIDENCE

IV.

Prevalence and Risk Factors of Osteoporosis in Chinese Postmenopausal Women Awaiting Total Knee Arthroplasty

Background

Total knee arthroplasty (TKA) complications associated with low bone quality are challenging for orthopaedic surgeons to treat, but little is known about bone quality in Chinese postmenopausal women awaiting TKA. This study investigated the incidence of osteoporosis (OP) and explored the preoperative risk factors for OP in this population.

Methods

We retrospectively reviewed the data of Chinese postmenopausal women who were indicated for TKA between May 2017 and June 2020. The bone mineral density (BMD) of the hip and lumbar spine and multiple preoperative parameters were collected and analyzed. Binary logistic regression analysis was performed to identify independent risk factors for OP in this population.

Results

A total of 204 postmenopausal women with advanced knee OA were included in the study (age: 69.7±8.5 years; body mass index [BMI]: 25.5±4.0 kg/m2). The OP prevalence among all participants was 59.8%, and the patients aged 60–80 years had a significantly lower BMD than did the age/ethnicity-adjusted population. An age ≥60 years, a BMI<25, and the presence of a varus knee deformity were independent risk factors for preoperative OP in the postmenopausal women awaiting TKA.

Conclusion

The prevalence of OP in Chinese postmenopausal women awaiting TKA is higher than that in the age/ethnicity-adjusted normal population. An age ≥60 years, a BMI<25, and the presence of a varus knee deformity are independent risk factors that can be used to predict preoperative OP in this population.

Progress in the treatment of knee osteoarthritis with high tibial osteotomy: a systematic review

BACKGROUND

High tibial osteotomy (HTO) has been used for over 60 years in clinical practice and mainly comprises two major techniques: closed wedge high tibial osteotomy (CWHTO) and open wedge high tibial osteotomy (OWHTO). However, these have been gradually replaced by total knee arthroplasty (TKA), due to inconsistent clinical results and many complications. With the concept of knee-protection and ladder treatment of osteoarthritis, as an effective minimally invasive treatment for knee osteoarthritis, HTO has once again received attention.

METHODS

A systematic literature search was conducted in PubMed, Embase, ClinicalKey, CNKI, and the China Wanfang database. The search terms relating to osteoarthritis and high tibial osteotomy were used. Studies were considered eligible if the participants were adults with knee osteoarthritis (KOA) who had undergone HTO. A total of two reviewers participated in the selection of the studies. Reviewer 1 was assigned to screen titles and abstracts, and reviewer 2 to screen full-text data. Data extraction was completed by reviewer 2, and 30% were checked by the research team. Potential conflicts were resolved through discussion. The methodological quality was assessed using a risk of bias, based on the Cochrane handbook and Newcastle-Ottawa assessment scale. The outcome indicators are (1) posterior slope of tibial plateau, (2) the height of the patella, (3) fracture in the osteotomy plane, (4) survival rate, (5) special surgery knee score (HSS), and (6) the recurrence of varus deformity of the included studies were evaluated according to the guidelines of the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) working group (Atkins et al., BMJ 328:1490, 2004).

RESULTS

Among the 18 articles included, 10 were prospective cohort studies, five were randomized controlled trial (RCT) studies, one was prospective comparative study (PCS), one was retrospective comparative study (RCS), and one was retrospective cohort. The earliest publication year was 1999, and the most recent was 2018. A total of 6555 eligible cases were included, comprised of 3351 OWHTO patients and 3204 CWHTO patients. Five RCT were assessed using risk of bias, based on the Cochrane handbook. Eleven cohort studies and two case-control studies were assessed using the Newcastle-Ottawa assessment scale. These six outcome indicators for a total of twenty-four evidence individuals were evaluated separately, among which the GRADE classification of 1, 2, and 6 was medium quality, and 3, 4, and 5 were low quality. Based on our systematic review, regardless of whether the chosen procedure was OWHTO or CWHTO, both HSS scores increased significantly as compared with the preoperative scores. Compared with CWHTO, the height of the patella and tibial posterior slope angle increased following OWHTO. Additionally, OWHTO has a better long-term survival rate and lower fracture rate, supporting OWHTO as the first treatment choice.

CONCLUSIONS

For young patients with knee osteoarthritis (KOA), high tibial osteotomy (HTO) can be considered as a treatment option to replace total knee arthroplasty (TKA) to reduce the economic burden and promote the reasonable allocation of medical resources. This study shows that compared with CWHTO, OWHTO has certain advantages in long-term survival rate and lower fracture rate, but the level of evidence is lower. In the future, we will need larger sample sizes and longer follow-up randomized controlled trials to improve our research.

The Functional Status of the ACL in Varus OA of the Knee: The Association With Varus Deformity and Coronal Tibiofemoral Subluxation

BACKGROUND

The present article analyzes the association of the functional anterior cruciate ligament (ACL) status and the overall varus deformity and coronal tibiofemoral subluxation (CTFS) in varus OA of the knee.

METHODS

One hundred consecutive knees with varus OA in 84 patients were prospectively included. Knees were divided into two groups, in accordance with the ACL status (functionally sufficient or insufficient). All included patients were potential candidates for unicompartmental knee arthroplasty with predominantly medial compartment OA. Knees with Kellgren/Lawrence ≥ grade 3 in the lateral compartment were excluded leaving 79 knees to be included in this study. Mechanical varus deformity and CTFS were evaluated on AP radiographs and valgus stress radiographs, and compared between the two groups.

RESULTS

Knees with a functionally insufficient ACL had significantly more varus deformity on hip-to-ankle AP standing radiographs (P = .001) and on valgus stress radiographs (P = .017). CTFS on AP standing radiographs was significantly higher (P = .045) in knees with a functionally insufficient ACL. Seventy-three percent (8/11) of the ACL-insufficient knees had a varus deformity of ≥10° and 64% (7/11) of ACL-insufficient knees had CTFS ≥ 6mm. By contrast, only one patient (2%, 1/41) with an insufficient ACL had< 10° varus deformity and a CTFS of < 6mm.

CONCLUSION

Functional ACL insufficiency in osteoarthritic varus knees is associated with greater varus deformity and more advanced CTFS. Seventy-three percent of ACL-insufficient knees had a varus deformity of ≥10° and 64% of ACL-insufficient knees a CTFS of ≥ 6mm. In the work-up for medial unicompartmental knee arthroplasty, functional ACL insufficiency is likely in knees with varus deformity of ≥10° and CTFS of ≥ 6mm.

Coronal tibiofemoral subluxation is a risk factor for postoperative overcorrection in high tibial osteotomy

BACKGROUND

Severe tibiofemoral (TF) subluxation > 10 mm is a contraindication for high tibial osteotomy (HTO). However, the relationship between the degree of preoperative TF subluxation at < 10 mm and postoperative radiographic/clinical outcomes remains unclear.

METHODS

Sixty-seven patients who underwent open wedge HTO with a planned postoperative mechanical femorotibial angle (mFTA) of three degrees valgus were retrospectively studied. The minimal subluxation (MIN) group included 39 patients with TF subluxation < 5 mm, while the moderate subluxation (MOD) group included 28 patients with TF subluxation of five to 10 mm. The preoperative and one-year postoperative mFTA, TF subluxation, medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), preoperative Kellgren-Lawrence (K-L) grade and varus-valgus laxity were evaluated. Clinical scores and pain visual analogue scale (VAS) were also analyzed.

RESULTS

The mean preoperative TF values in the MIN and MOD groups were 3.1±1.0 mm and 6.7±1.6 mm (mean±standard deviation, p < 0.001), respectively, with no significant difference in K-L grades. The MIN group demonstrated a significantly smaller varus preoperative mFTA (p < 0.001), larger MPTA (p = 0.011), smaller JLCA (p = 0.004), and less varus laxity (p = 0.023). Postoperative TF subluxation, MPTAs, and JLCAs did not differ significantly between the two groups, while the postoperative mFTA was significantly different (p = 0.001), with unintended overcorrection in the MOD group. No significant difference in clinical scores and VAS were observed.

CONCLUSIONS

After HTO, compared to patients with TF subluxation < 5 mm, patients with TF subluxation of five to 10 mm were more likely to demonstrate unintended valgus overcorrection on one-year postoperative radiography.

Coronal tibiofemoral subluxation is correlated to correction angle in medial opening wedge high tibial osteotomy

PURPOSE

This study aimed to analyse the change in coronal tibiofemoral (CTF) subluxation after high tibial osteotomy and to determine demographic variables associated with CTF subluxation. The change in CTF subluxation was hypothesised to be associated with the magnitude of correction of lower limb alignment and medial proximal tibial angle (MPTA).

METHODS

A total of 103 consecutive knees in 86 patients who underwent medial opening wedge high tibial osteotomy for symptomatic medial compartment knee osteoarthritis were retrospectively analysed. The normal %CTF subluxation value, which was defined as a subluxation of the proximal tibia relative to the distal femur on the lateral edge of the femorotibial joint, was determined from 60 normal knees. The association between CTF subluxation and the Knee Society Score (KSS) and radiographic parameters was examined.

RESULTS

The normal range for %CTF subluxation was defined as - 1.8 to 5.6%. Following osteotomy, Δ%CTF subluxation reduced from a mean of 4.5% (- 12.1 to - 4.6%) to 0.7% (- 6.8 to 8.2%), resulting in a decrease in lateral tibiofemoral subluxations concomitant with an increase in medial subluxations. The reduction in CTF subluxation correlated moderately with MPTA change (r = - 0.454, p < 0.001) and weakly with preoperative lower limb alignment as represented by hip-knee-ankle angle and %weight-bearing line. Multivariate regression analysis showed that ΔMPTA was a significant contributor of Δ%CTF subluxation.

CONCLUSION

Osteotomy reduced CTF subluxation, which was correlated with MPTA change. Postoperative MPTA should be considered during surgical planning, and a postoperative MPTA of approximately 93.5° may be an appropriate target to reduce CTF subluxation by obtaining normal CTF congruency.

LEVEL OF EVIDENCE

Level IV therapeutic, retrospective, cohort study.

Total knee arthroplasty in the varus knee: tips and tricks

Varus knee deformity is very common, and it can be classified according to the severity and reducibility of the deformity. Pre-operative planning is mandatory to obtain a good result. Both clinical and radiological planning should be carefully performed, particularly focused on collateral ligament deficiency. In most of the cases, a postero-stabilized implant is necessary, but in the presence of a varus thrust, a midlevel constrained (MLC) implant may be necessary. Rarely, if a severe extra-articular deformity is present, a femoral osteotomy and a high constrain implant may be necessary. In most of the cases, a standard midline approach can be performed. Soft tissue balancing is crucial, avoiding excessive releases of the medial collateral ligament (MCL). In the presence of severe deformity, more aggressive procedure such as tibial reduction osteotomy or sliding medial epicondyle osteotomy can be performed. In literature, good outcomes are reported for total knee arthroplasty (TKA) in varus deformity. In this manuscript, the available literature on TKA in varus deformity is analyzed, and the preferred surgical techniques of the authors are described.

Annual trends in knee arthroplasty and tibial osteotomy: Analysis of a national database in Japan

BACKGROUND

Various nationwide studies have reported differing annual trends in utilization of knee arthroplasty and tibial osteotomy. Using the Diagnosis Procedure Combination database in Japan, the present series examined annual trends and demographics in total knee arthroplasty (TKA), unicompartmental knee arthroplasty (UKA) and tibial osteotomy.

METHODS

All patients were identified who underwent TKA, UKA or tibial osteotomy for osteoarthritis, osteonecrosis or rheumatoid arthritis of the knee between July 2007 and March 2015.

RESULTS

A total of 170,433 cases of TKA, 13,209 cases of UKA and 8760 cases of tibial osteotomy were identified. The proportion of patients undergoing UKA rose from 4.0% in 2007 to 8.1% in 2014 (P<0.001), and that of tibial osteotomy from 2.6% in 2007 to 5.5% in 2014 (P<0.001); the proportion undergoing TKA fell from 93.4% in 2007 to 86.3% in 2014 (P<0.001). Between 2007 and 2014 the proportions of patients with osteonecrosis who underwent UKA and tibial osteotomy increased from 34.7% and 11.6% to 38.6% and 16.2%, respectively (P=0.001 for UKA and P=0.004 for tibial osteotomy). The proportions of patients with osteonecrosis undergoing UKA or tibial osteotomy were significantly greater than those with other diagnoses (P<0.001 for both).

CONCLUSIONS

The popularity of UKA and tibial osteotomy in Japan increased during the period 2007-2014 at the expense of TKA. The proportions of UKA and tibial osteotomy in patients with osteonecrosis also increased, and were larger than those in patients with other causative diseases.

Coronal tibiofemoral subluxation is not an independent risk factor for total knee arthroplasty in patients with moderate to severe varus-osteoarthritis: data from the "Osteoarthritis Initiative"

PURPOSE

Only few prognostic factors for progression of knee osteoarthritis are well established, including varus malalignment. The purpose of this study was to evaluate whether coronal tibiofemoral subluxation is a predictor for total knee arthroplasty.

METHODS

Patients from the progression subcohort of the longitudinal database "Osteoarthritis Initiative" with moderate to severe osteoarthritis and varus malalignment of greater than 3 degrees were included. Patients who underwent total knee arthroplasty were matched with patients treated conservatively. Subluxation was measured on full limb length X-rays. Cox regression analysis was performed to retrospectively evaluate subluxation as a risk factor for total knee arthroplasty and check for a possible association between subluxation and pain at the beginning of the observation period in this study.

RESULTS

A total of 215 patients were included. Cox regression demonstrated that varus malalignment increased the hazard to undergo surgery by 16% (HR 1.158, p = 0.008) while subluxation did not (HR 1.12, p = 0.11). Furthermore, subluxation was neither associated with poor WOMAC (OR 1.13, p = 0.194) nor KOOS (OR 1.11, p = 0.256) knee pain scores at the beginning of the observation period.

CONCLUSION

The results presented show that subluxation is neither an independent risk factor for total knee arthroplasty, nor for poor pain scores.

LEVEL OF EVIDENCE

III.

Younger patients have less severe radiographic disease and lower reported outcome scores than older patients undergoing total knee arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) has been successful for many younger patients, but some experience residual symptoms or dissatisfaction. We performed this study to assess the relationship between radiographic disease severity and patient demographic features on patient reported TKA outcome scores.

METHODS

We compared 100 TKAs performed for 82 patients ≤55years old with 100 gender-matched TKAs performed for 85 patients between 65 and 75years old. These study cases represented 25% and 21%, respectively, of TKAs performed between January 2006 and June 2011. Radiographic disease severity was determined from preoperative weight bearing AP and lateral radiographs. Patient reported outcome instruments (SF-12, Knee Society function, and WOMAC) were assessed for all patients within six months before surgery and postoperatively at a mean of 20months after TKA.

RESULTS

Although younger patients had less mean articular cartilage loss (p<0.01), osteoarthritis severity (p<0.01), and Kellgren-Lawrence grade (p=0.05), they reported lower preoperative scores (p<0.01) exceeding the MCID for SF-12 mental health (8.3 points), WOMAC pain (12.1 points), and WOMAC physical function (6.9 points). While substantial improvement was noted, WOMAC pain scores remained lower than those reported by older TKA patients (11.5 points, p<0.05).

CONCLUSION

Younger patients with less severe radiographic arthritis experience significant improvement with TKA, but outcome scores do not match those attained by older patients with more severe radiographic disease.

Coronal tibiofemoral subluxation in knee osteoarthritis

OBJECTIVE

To analyze knees in varying stages of osteoarthritis (OA) for the presence of coronal tibiofemoral (CTF) subluxation and to determine if CTF subluxation severity is related to knee OA worsening.

METHODS

We retrospectively evaluated CTF subluxation and limb alignment in 113 patients with different stages of knee OA who were being considered for an arthroplasty procedure. Knee OA was classified as "mild" or "severe" according to Kellgren-Lawrence scale. CTF subluxation was measured in the study groups and in 40 knees of healthy controls using software developed specifically on the basis of Iterative Closest Point mathematical algorithm.

RESULTS

Mean CTF subluxation in "mild OA" and "severe OA" groups was 3.5% (±2) and 3.5 % (±5) of the tibial plateau, respectively. For both the mild and severe OA groups, CTF subluxation was significantly increased compared to the 1.4% (±1) CTF subluxation in the control group, (p < 0.0001) and (p = 0.012), respectively. However, there was no significant difference in CTF subluxation between the mild OA and severe OA groups (p = 0.75). Limb varus malalignment in mild OA and severe OA groups was 3.6° (±2.2) and 5.3° (±2.6), respectively. Both significantly increased comparing to the 1° (±0.7) control group alignment (p < 0.0001). Varus malalignment in the severe OA group was significantly increased comparing to the mild OA group (p = 0.0003).

CONCLUSIONS

CTF subluxation is a radiographic finding related to knee OA which occurs mainly in the early stages of the osteoarthritic process and stagnates as OA progresses.

Multivariate Radiological-Based Models for the Prediction of Future Knee Pain: Data from the OAI

In this work, the potential of X-ray based multivariate prognostic models to predict the onset of chronic knee pain is presented. Using X-rays quantitative image assessments of joint-space-width (JSW) and paired semiquantitative central X-ray scores from the Osteoarthritis Initiative (OAI), a case-control study is presented. The pain assessments of the right knee at the baseline and the 60-month visits were used to screen for case/control subjects. Scores were analyzed at the time of pain incidence (T-0), the year prior incidence (T-1), and two years before pain incidence (T-2). Multivariate models were created by a cross validated elastic-net regularized generalized linear models feature selection tool. Univariate differences between cases and controls were reported by AUC, C-statistics, and ODDs ratios. Univariate analysis indicated that the medial osteophytes were significantly more prevalent in cases than controls: C-stat 0.62, 0.62, and 0.61, at T-0, T-1, and T-2, respectively. The multivariate JSW models significantly predicted pain: AUC = 0.695, 0.623, and 0.620, at T-0, T-1, and T-2, respectively. Semiquantitative multivariate models predicted paint with C-stat = 0.671, 0.648, and 0.645 at T-0, T-1, and T-2, respectively. Multivariate models derived from plain X-ray radiography assessments may be used to predict subjects that are at risk of developing knee pain.

Trends in High Tibial Osteotomy and Knee Arthroplasty Utilizations and Demographics in Korea From 2009 to 2013

We analyzed the records of 29,895 high tibial osteotomies (HTOs), 12,589 unicompartmental knee arthroplasties (UKAs) and 363,386 total knee arthroplasties (TKAs) performed from 2009 to 2013 in Korea. They were compared with the latest nationwide registry reports of seven Western countries. Over the last 5 years, in Korea, the number of HTO, UKA and TKA increased by 210%, 138%, and 18%, respectively. The largest increase was observed in 55-64 year olds in HTO and UKA, while the largest increase in TKA was in ≥75 year olds. Females commonly had a three- to seven-fold higher rate in all procedures. Worldwide, the use of HTO and UKA decreased or remained stable, whereas that of TKA increased steadily, even in younger patients.

Changes of knee joint and ankle joint orientations after high tibial osteotomy

OBJECTIVE

We sought to determine (1) whether change in the tibial plateau inclination (TPI) after high tibial osteotomy (HTO) is different from change in the knee joint line orientation (KJLO) relative to the ground; (2) whether, in varus knee OA patients before and after HTO, these radiographic measures are different from those in normal control; and (3) whether the postoperative values of the TPI and KJLO relative to the ground are associated with short term clinical outcome scores after HTO.

DESIGN

Fifty patients who underwent HTO and 75 normal controls were assessed with four radiographic measures. We compared the measures before HTO with those after HTO and with those of the normal controls, then examined associations between the postoperative radiographic measures and clinical outcome scores 1-year after HTO.

RESULTS

After HTO, TPI increased 9.0°, whereas KJLO relative to the ground only increased 4.1°, with a compensatory change of the ankle joint line orientation. However, the postoperative KJLO relative to the ground in the HTO group was significantly different from that of the normal controls (mean difference, 4.9°; P < 0.001). In the multiple regression analyses, the postoperative radiographic measures were not associated with outcome clinical scores 1 year after HTO.

CONCLUSION

After HTO the relative KJLO changed significantly less than did the anatomical geometry of the proximal tibia. Although the KJLO after the HTO was still significantly different from that of normal knees, its value did not adversely affect clinical outcome scores 1 year after HTO.

How effective is multiple needle puncturing for medial soft tissue balancing during total knee arthroplasty? A cadaveric study

We investigated the quantitative effect and risk factors for over-release during multiple needle puncturing (MNP) for medial gap balancing in varus total knee arthroplasty (TKA). Of the ten pairs of cadaveric knees, one knee from each pair was randomly assigned to undergo MNP in extension (E group), while the other knee underwent MNP in flexion (F group). The increased extension and 90° flexion gaps after every five needle punctures were measured until over-release occurred. The extension gap (< 4mm) and the 90° flexion gap (< 6mm) gradually increased in both groups. The 90° flexion gaps increased more selectively than did the extension gaps. MNP in the flexed knee, a narrow MCL, and severe osteoarthritis were associated with a smaller number of MNPs required to over-release.

Coronal tibiofemoral subluxation: a new measurement method

BACKGROUND

Coronal tibiofemoral (CTF) subluxation is a common finding in knee osteoarthritis (OA) which can be related to poor pain scores and tibial spine impingement. In this study we describe a new method for measuring CTF subluxation and present validation of the method using cadaveric knees.

METHODS

A prototype software code based on the ICP mathematical algorithm was developed to measure CTF subluxation; the code finds the rigid transformation that best aligns the articular surfaces, measures CTF subluxation and the angle between articular surfaces. For validation, three stripped fresh frozen cadaveric knee specimens were transfixed to a specially designed knee fixation device where tibiofemoral angle and CTF subluxation can be measured directly. Fluoroscopic images were obtained with the tibiofemoral joint in neutral alignment and with 5, 10 and 15 (mm) of medial and lateral subluxation. This procedure was repeated with a neutral tibiofemoral angle, 10° of varus and 10° of valgus. All images were analyzed independently by two investigators using the prototype software.

RESULTS

The interclass correlation coefficient between the two investigators for CTF subluxation and tibiofemoral angle was 0.93 and 0.99 respectively. The CTF subluxation and tibiofemoral angle measured by the software correlated to the CTF subluxation and tibiofemoral angle were defined using the knee fixation device, with Pearson product moments of 0.86 and 0.94 respectively.

CONCLUSION

Our suggested prototype software is precise, repeatable and reliable at measuring CTF subluxation and tibiofemoral angle. It may prove to be a useful tool to evaluate CTF subluxation in a clinical setting.

Causes, risk factors, and trends in failures after TKA in Korea over the past 5 years: a multicenter study

BACKGROUND

Failure after total knee arthroplasty (TKA) may be related to emerging technologies, surgical techniques, and changing patient demographics. Over the past decade, TKA use in Korea has increased substantially, and demographic trends have diverged from those of Western countries, but failure mechanisms in Korea have not been well studied.

QUESTIONS/PURPOSES

We determined the causes of failure after TKA, the risk factors for failure, and the trends in revision TKAs in Korea over the last 5 years.

METHODS

We retrospectively reviewed 634 revision TKAs and 20,234 primary TKAs performed at 19 institutes affiliated with the Kleos Korea Research Group from 2008 to 2012. We recorded the causes of failure after TKA using 11 complications from the standardized complication list of The Knee Society, patient demographics, information on index and revision of TKAs, and indications for index TKA. The influences of patient demographics and indications for index TKA on the risk of TKA failure were evaluated using multivariate regression analysis. The trends in revision procedures and demographic features of the patients undergoing revision TKA over the last 5 years were assessed.

RESULTS

The most common cumulative cause of TKA failure was infection (38%) followed by loosening (33%), wear (13%), instability (7%), and stiffness (3%). However, the incidence of infections has declined over the past 5 years, whereas that of loosening has increased and exceeds that of infection in the more recent 3 years. Young age (odds ratio [OR] per 10 years of age increase, 0.41; 95% confidence interval [CI], 0.37-0.49) and male sex (OR, 1.88; 95% CI, 1.42-2.49) were associated with an increased risk of failure. The percentage of revision TKAs in all primary and revision TKAs remained at approximately 3%, but the annual numbers of revision TKAs in the more recent 3 years increased from that of 2008 by more than 23%.

CONCLUSIONS

Despite a recent remarkable increase in TKA use and differences in demographic features, the causes and risk factors for failures in Korea were similar to those of Western countries. Infection was the most common cause of failure, but loosening has emerged as the most common cause in more recent years, which would prompt us to scrutinize the cause and solution to reduce it.

Correction of varus deformity during TKA with reduction osteotomy

BACKGROUND

Reduction osteotomy (removing the posteromedial tibial bony flare) is one step to aid in achieving deformity correction in varus arthritic knees during TKA. However, the amount of deformity correction achieved with reduction osteotomy during TKA is unclear.

QUESTIONS/PURPOSES

We therefore addressed the following questions: (1) What is the amount of deformity correction achieved with reduction osteotomy during TKA in varus knees? (2) What is the correlation of amount of deformity correction achieved to the amount of bone osteotomized and the degree of varus deformity?

METHODS

We prospectively collected and analyzed intraoperative data on the degree of varus deformity before and after reduction osteotomy (using computer navigation) and the amount of reduction osteotomy performed (using a measuring scale) in 71 primary, computer-assisted TKAs.

RESULTS

For a mean reduction osteotomy of 7.5 ± 2 mm, a mean correction of 3.5° ± 1° was achieved; a mean osteotomy of 2 mm was required (confidence interval, 1.7-2.6 mm) for every 1° correction of varus deformity. Degree of varus correction achieved correlated positively with the amount of osteotomy performed, especially in knees with preoperative varus deformity of < 15° (r = 0.77, p < 0.001) and the preosteotomy residual varus deformity correlated positively with the amount of correction achieved (r = 0.81, p < 0.001).

CONCLUSIONS

Reduction osteotomy can achieve deformity correction in a predictable 2 mm for 1° in most varus arthritic knees during TKA. Further studies are required to ascertain its effectiveness as a soft tissue-sparing step when performed early on during TKA to achieve deformity correction.

Coronal limb alignment and indications for high tibial osteotomy in patients undergoing revision ACL reconstruction

BACKGROUND

Failed ACL reconstruction frequently is accompanied by irreparable medial meniscal tear and/or visible osteoarthritis (OA) in the medial tibiofemoral joint. Thus, assessment for the presence of varus malalignment is important in caring for patients in whom revision ACL reconstruction is considered.

QUESTIONS/PURPOSES

We determined whether patients undergoing revision ACL reconstruction (1) have more frequent varus malalignment coupled with more severe degrees of medial meniscal injury and/or medial tibiofemoral OA, and (2) would meet potential indications for high tibial osteotomy more frequently than patients undergoing primary ACL reconstruction.

METHODS

We compared 58 patients undergoing revision ACL reconstruction and 116 patients undergoing primary ACL reconstruction. The mechanical tibiofemoral angle and the weight loading line (%) of the knee were measured. Additionally, radiographic degrees of OA in the tibiofemoral joints, and meniscal conditions were assessed. Then, proportions of potential candidates for high tibial osteotomy between the two groups were compared based on the following indications: (1) weight loading line less than 5%, (2) weight loading line less than 25% and medial tibiofemoral OA Kellgren-Lawrence Grade 3 or greater, or (3) weight loading line less than 25% and Kellgren-Lawrence Grade 2 medial tibiofemoral OA plus subtotal or total medial meniscectomy status.

RESULTS

The revision ACL reconstruction group had more frequent varus malalignment in terms of proportion of knees with more varus mechanical tibiofemoral angle than varus 5° (19% versus 8%, p = 0.029) and knees with weight loading line less than 25% (22% versus 9%, p = 0.011). This group also had more frequent high-grade injury of the medial meniscus (34% versus 16%, p = 0.007) and tended to have more frequent higher-grade radiographic OA at the medial tibiofemoral joint (19% versus 9%, p = 0.076). The percentage of patients meeting potential indications for high tibial osteotomy was greater in this group (14% versus 2%, p = 0.003).

CONCLUSIONS

We found that many patients undergoing revision ACL surgery may be reasonable candidates for concurrent high tibial osteotomy to address concomitant alignment and OA issues in the medial compartment. However, whether that additional intervention is offset by added risk and morbidity should be the focus of a future study, as it cannot be answered by a study of this design.

The association between radiographic severity and pre-operative function in patients undergoing primary knee replacement for osteoarthritis

OBJECTIVE

To determine the association between radiographic osteoarthritis (OA) and pre-operative function in patients undergoing primary knee replacement.

METHODS

Single centre study examining pre-operative outcomes in a consecutive series of 525 patients who underwent primary knee replacement for OA between January 2006 and December 2007. Pre-operative data included: demographics, American Society of Anaesthesiologists (ASA) status and OA in the contralateral knee. The International Knee Society (IKS) rating and Short Form-12 (SF-12) were recorded for each patient. Pre-operative radiographs were read by a single observer for Kellgren and Lawrence (K&L) grading and Osteoarthritis Research Society International (OARSI) atlas features. Multiple linear regression was used to assess the strength of associations between radiographic OA severity and function, adjusting for clinically relevant variables.

RESULTS

Lateral tibiofemoral osteophyte grade was an independent predictor of pre-operative function as determined by the functional sub-scale of the IKS in patients undergoing primary knee replacement (coefficient=2.58, p=0.033). No associations were evident between pre-operative function and modified K&L, joint space narrowing, Ahlbäck attrition and coronal plane deformity. Other statistically significant predictors of poorer pre-operative function included: advancing age, female gender, knee pain and poorer SF-12 mental component summary scores which including osteophyte grade accounted for 24.6% of the variation in functional scores, (r=0.496).

CONCLUSION

Osteophytes in the lateral compartment of the knee were associated with pre-operative function in patients with advanced knee OA. Further studies are required which examine individual radiographic features specifically in patients with advanced knee OA to determine their relationship to pre-operative pain and function.