Range of motion correlates with patient perception of TKA outcome

Stratification of Outpatient Physical Therapy Following Total Knee Arthroplasty: Knee Arthroplasty Physical Therapy Pathways (KAPPA) Nonrandomized Controlled Trial

BACKGROUND

Outpatient physical therapy following total knee arthroplasty (TKA) is often considered crucial for an effective recovery. However, recent evidence suggests that a self-directed pathway may yield similar benefits to supervised care. Despite this, there appear to be no established criteria to determine who can successfully self-direct their rehabilitation versus those who would benefit from outpatient physical therapy. This study aimed to determine if early postoperative criteria can stratify TKA patients into a self-directed or supervised physical therapy pathway without compromising outcomes.

METHODS

Overall, 60 TKA patients were initially allocated to a self-directed, unsupervised protocol for their postoperative rehabilitation. Baseline demographics, along with functional and self-reported outcomes, were assessed preoperatively and at 2 weeks, 6 weeks, and 4 months following surgery. Patients were referred to supervised outpatient physical therapy if they met any of the following Knee Arthroplasty Physical Therapy Pathways (KAPPA) criteria: (1) knee flexion range of motion <90 degrees; (2) knee extension range of motion lacking >10 degrees; or (3) dissatisfaction with the progress of their rehabilitation.

RESULTS

At 2 weeks post-TKA, 28 participants met the KAPPA criteria for supervised physical therapy for reasons of knee flexion <90 degrees (61%), a lack of knee extension >10 degrees (36%), or not being satisfied with the progress of their recovery (3%). The remaining 32 participants continued with a self-directed rehabilitation pathway. All outcomes assessed favored the self-directed group at 2 weeks, however, after an average of 4 supervised physical therapy sessions at 4 months there were no longer any differences between the 2 groups.

CONCLUSIONS

Over half of the included participants could self-direct their rehabilitation following TKA without supervised physical therapy while also maintaining excellent clinical outcomes. For those who met KAPPA criteria at 2 weeks post-TKA, 4 supervised physical therapy sessions appeared to be beneficial when outcomes were reassessed at 4 months.

Multicenter, prospective cohort study: immediate postoperative gains in active range of motion following robotic-assisted total knee replacement compared to a propensity-matched control using manual instrumentation

BACKGROUND

Range of motion (ROM) following total knee replacement (TKR) has been associated with patient satisfaction and knee function, and is also an early indicator of a successful procedure. Robotic-assisted TKR (raTKR) is considered to reproduce more precise resections, and, as a result, may be associated with improved early patient satisfaction compared to manual TKR (mTKR). The purpose of this study was to evaluate the early postoperative active ROM (aROM) between raTKR and mTKR.

METHODS

A total of 216 mTKR patients were propensity-matched, in terms of age, gender, comorbidities, and BMI, to 216 raTKR cases. Intraoperative and immediate postoperative adverse events were collected. Knee flexion and extension aROM were measured preoperatively and at one- and three months after operation.

RESULTS

Changes in flexion aROM were significantly greater in raTKR vs. mTKR at one- (6.9°, 95% CI: 3.5, 10.4°) and three months (4.9°, 95% CI: 2.1, 7.7°). Flexion aROM was greater at three postoperative months compared to preoperative aROM only in the raTKR group, and raTKR patients had higher odds of achieving ≥ 90° of flexion at one month after operation (OR: 2.15, 95% CI: 1.16, 3.99). There were no significant differences between groups in intraoperative (P > 0.999) or postoperative adverse events.

CONCLUSIONS

Compared with mTKR, raTKR resulted  in less loss of aROM immediately after operation and a faster recovery of aROM within three months after operation.

TRIAL REGISTRATION

Clinicaltrials.gov (NCT# 03737149).

Short-term clinical outcomes of primary total knee arthroplasty with a new-type kinematic retaining implant: A comparison with preexisting cruciate retaining prosthesis

Despite the success of total knee arthroplasty (TKA), current implant designs could not consistently restore the physiological knee kinematics, especially in cruciate-retaining (CR) implants. This study aimed to investigate the short-term clinical outcomes, particularly patient satisfaction, of primary TKA employing a new-type kinematic retaining (KR) implant. We analyzed 149 cases applied the KR implant at our institutions during June 2017 to May 2019. The effectiveness of this implant design was compared with another CR one (171 cases). Both groups underwent primary TKA in the same period and all patients completed 2 years of follow-up. Perioperative changes in range of motion (ROM), Knee Score, function score, and patient satisfaction by Forgotten Joint Score-12 (FJS-12) method were evaluated. Postoperative ROM, Knee Score, and function score were significantly improved at 1 year after surgeries and maintained for another year in both KR and CR groups. The improvement rate of ROM in KR group (108.1%) was substantially higher than that in CR (104.5%), even 4% increase could have affected patients' satisfaction in a real-world setting. Regarding the patient satisfaction, such 4 items as climbing stairs, walking on a bumpy road, doing housework or gardening, and taking a walk or hiking were significantly enhanced in KR cases compared to CR. There were no loosening or revision cases and the short-term survivorships of both implants were 100%. In addition, there has been no case of obvious complications in both groups during and after surgeries. The results of the present study suggest that this novel KR prosthesis can reproduce physiological knee kinematics, recover its functions, and contribute to pain relief after TKA. TKA procedure using the KR implant should be a good surgical option to improve postoperative outcomes.

Prospective, Randomized Clinical Trial Comparing a Novel Motion-Assistive Device to Standard Physical Therapy for Initial Management of Knee Range of Motion after Primary Total Knee Arthroplasty

This prospective randomized clinical trial assessed a novel device for initial management of knee range of motion (ROM), pain, and function after total knee arthroplasty (TKA). Primary TKA patients with preoperative ROM of at least 5° to 115° were randomized to initial knee motion management: Mizzou BioJoint Flex-novel motion-assistive device with prescribed physical therapy or standard physical therapy-prescribed physical therapy. ROM, pain score, and knee injury and osteoarthritis score for joint replacement (KOOSjr) were obtained preoperatively and 2 weeks, 6 weeks, and 3 months postoperatively. Patient satisfaction for both cohorts and subjective assessments of the MBF device were assessed at 3 months. Readmissions, reoperations, and complications were assessed through 1 year. Nineteen patients were randomized to each cohort, with no significant preoperative differences in demographics, pain score, KOOSjr score, or ROM. Six SPT (31.6%) and 3 MBF (15.8%) patients failed to regain preoperative ROM (p = 0.044). One SPT (5.3%) and eight MBF (42%) patients exceeded 125° ROM (p = 0.019) by 3 months. Total ROM (p = 0.039), pain (p = 0.0068), and function (p = 0.0027) were significantly better for MBF at 3 months. MBF patients reported significantly higher satisfaction (mean, 9.4 ± 1.1 vs. 8.0 ± 1.8, respectively; p = 0.0084). One patient in each group underwent manipulation under anesthesia. No other readmissions, reoperations, or complications were reported. A novel durable medical equipment device can provide a safe and effective patient-controlled method for initial management of knee ROM, pain, and function after primary TKA with potential clinically meaningful advantages over physical therapy alone. In conjunction with physical therapy, management with this novel knee flexion device more effectively restored knee ROM and early patient function when compared with therapy alone and was associated with higher proportions of patients regaining minimum (115°) and desired (125°) levels of knee ROM and clinically meaningful differences in pain scores, knee function, and patient satisfaction. This is a Level 1, prospective trial study.

Synergistic effects of robotic surgery and IPACK nerve block on reduction of opioid consumption in total knee arthroplasty

Background

There are numerous strategies to combat postoperative analgesia and expedite recovery after total knee arthroplasty (TKA). The purpose of this study was to determine opioid consumption, length of stay, and functional outcomes after robotic versus standard TKA in the setting of various regional pain modalities.

Methods

A consecutive series of patients treated with unilateral primary robotic or standard TKA from January 2018-February 2021 were retrospectively identified. Regional pain modalities included peri-articular injection (PAI), adductor canal block (ACB), and infiltration between popliteal artery and capsule of knee (IPACK). Patient demographics, operative/perioperative variables, and postoperative function were recorded. Daily opiate consumption was calculated as morphine milligram equivalents (MME). Multivariate regression was performed to control for age, sex, and race.

Results

After review, 283 patients (177 Females; 106 Males) were included. Robotic TKA patients received IPACK + ACB (36), while standard TKA patients received either ACB (45), IPACK + ACB (167), or PAI (35). Daily inpatient opioid consumption in the standard IPACK + ACB (p = 0.02) and robotic IPACK + ACB groups (p = 0.0001) was significantly lower compared to standard ACB. When combined with IPACK block, robotic procedures synergistically lowered opiate consumption (p = 0.004) compared to standard procedures and led to earlier discharge (p = 0.003). The robotic IPACK + ACB cohort also demonstrated improved early ambulation compared to standard ACB, (p = 0.05), whereas the same benefit was not seen for patients who received IPACK during standard TKA.

Conclusions

The utilization of IPACK block decreases inpatient postoperative opioid requirements following TKA. Robotic TKA and IPACK block appeared to have a synergistic effect on opioid consumption and postoperative recovery.

Patellofemoral Arthroplasty Results in Better Time-weighted Patient-reported Outcomes After 6 Years than TKA: A Randomized Controlled Trial

BACKGROUND

In a previous study, we reported the 2-year outcomes of a parallel-group, equivalence, randomized controlled trial (RCT; blinded for the first year) comparing patellofemoral arthroplasty (PFA) and TKA for isolated patellofemoral osteoarthritis (PF-OA). We found advantages of PFA over TKA for ROM and various aspects of knee-related quality of life (QOL) as assessed by patient-reported outcomes (PROs). Register data show increases in PFA revision rates from 2 to 6 years after surgery at a time when annual TKA revision rates are decreasing, which suggests rapidly deteriorating knee function in patients who have undergone PFA. We intended to examine whether the early advantages of PFA over TKA have deteriorated in our RCT and whether revision rates differ between the implant types in our study after 6 years of follow-up.

QUESTIONS/PURPOSES

(1) Does PRO improvement during the first 6 postoperative years differ between patients who have undergone PFA and TKA? (2) Does the PRO improvement at 3, 4, 5, and 6 years differ between patients who have undergone PFA and TKA? (3) Do patients who have undergone PFA have a better ROM after 5 years than patients who have had TKA? (4) Does PFA result in more revisions or reoperations than TKA during the first 6 postoperative years?

METHODS

We considered patients who had debilitating symptoms and PF-OA as eligible for this randomized trial. Screening initially identified 204 patients as potentially eligible; 7% (15) were found not to have sufficient symptoms, 21% (43) did not have isolated PF-OA, 21% (43) declined participation, and 1% (3) were not included after the target number of 100 patients had been reached. The included 100 patients were randomized 1:1 to PFA or TKA between 2007 and 2014. Of these, 9% (9 of 100) were lost before the 6-year follow-up; there were 12% (6 of 50) and 0% (0 of 50) deaths (p = 0.02) in the PFA and TKA groups, respectively, but no deaths could be attributed to the knee condition. There were no differences in baseline parameters for patients who had PFA and TKA, such as the proportion of women in each group (78% [39 of 50] versus 76% [38 of 50]; p > 0.99), mean age (64 ± 9 years versus 65 ± 9 years; p = 0.81) or BMI (28.0 ± 4.7 kg/m 2 versus 27.8 ± 4.1 kg/m 2 ; p = 0.83). Patients were seen for five clinical follow-up visits (the latest at 5 years) and completed 10 sets of questionnaires during the first 6 postoperative years. The primary outcome was SF-36 bodily pain. Other outcomes were reoperations, revisions, ROM, and PROs (SF-36 [eight dimensions, range 0 to 100 best, minimum clinically important difference {MCID} 6 to 7], Oxford Knee Score [OKS; one dimension, range 0 to 48 best, MCID 5], and Knee Injury and Osteoarthritis Outcome Score [KOOS; five dimensions, range 0 to 100 best, MCID 8 to 10]). Average PRO improvements over the 6 years were determined by calculating the area under the curve and dividing by the observation time, thereby obtaining a time-weighted average over the entire postoperative period. PRO improvements at individual postoperative times were compared for the patients who had PFA and TKA using paired t-tests. Range of movement changes from baseline were compared using paired t-tests. Reoperation and revision rates were compared for the two randomization groups using competing risk analysis.

RESULTS

Patients who underwent PFA had a larger improvement in the SF-36 bodily pain score during the first 6 years than those who underwent TKA (35 ± 19 vs. 23 ± 17; mean difference 12 [95% CI 4 to 20]; p = 0.004), and the same was true for SF-36 physical functioning (mean difference 11 [95% CI 3 to 18]; p = 0.008), KOOS Symptoms (mean difference 12 [95% CI 5 to 20]; p = 0.002), KOOS Sport/recreation (mean difference 8 [95% CI 0 to 17]; p = 0.048), and OKS (mean difference 5 [95% CI 2 to 8]; p = 0.002). No PRO dimension had an improvement in favor of TKA. At the 6-year time point, only the SF-36 vitality score differed between the groups being in favor of PFA (17 ± 19 versus 8 ± 21; mean difference 9 [95% CI 0 to 18]; p = 0.04), whereas other PRO measures did not differ between the groups. At 5 years, ROM had decreased less from baseline for patients who underwent PFA than those who had TKA (-4° ± 14° versus -11° ± 13°; mean difference 7° [95% CI 1° to 13°]; p = 0.02), but the clinical importance of this is unknown. Revision rates did not differ between patients who had PFA and TKA at 6 years with competing risk estimates of 0.10 (95% CI 0.04 to 0.20) and 0.04 (95% CI 0.01 to 0.12; p = 0.24), respectively, and also reoperation rates were no different at 0.10 (95% CI 0.04 to 0.20) and 0.12 (95% CI 0.05 to 0.23; p = 0.71), respectively.

CONCLUSION

Our RCT results show that the 2-year outcomes did not deteriorate during the subsequent 4 years. Patients who underwent PFA had a better QOL throughout the postoperative years based on several of the knee-specific outcome instruments. When evaluated by the 6-year observations alone and without considering earlier observations, we found no consistent difference for any outcome instruments, although SF-36 vitality was better for patients who underwent PFA. These combined findings show that the early advantages of PFA determined the results by 6 years. Our findings cannot explain the rapid deterioration of results implied by the high revision rates observed in implant registers, and it is necessary to question indications for the primary procedure and subsequent revision when PFA is in general use. Our data do not suggest that there is an inherent problem with the PFA implant type as otherwise suggested by registries. The long-term balance of advantages will be determined by the long-term QOL, but based on the first 6 postoperative years and ROM, PFA is still the preferable option for severe isolated PF-OA. A possible high revision rate in the PFA group beyond 6 years may outweigh the early advantage of PFA, but only detailed analyses of long-term studies can confirm this.

LEVEL OF EVIDENCE

Level I, therapeutic study.

In vivo knee kinematics of an innovative prosthesis design

Up to 20% of patients after total knee arthroplasty (TKA) are not satisfied with the result. Several designs of new implants try to rebuild natural knee kinematics. We hypothesized that an innovative implant design leads to better results concerning femoral rollback compared to an established implant design. For this pilot study, 21 patients were examined during TKA, receiving either an innovative (ATTUNE^TM Knee System (DePuy Inc.), n = 10) or an established (PFC^TM (DePuy Inc.), n = 11) knee system. All patients underwent computer navigation. Knee kinematics was assessed after implantation. Outcome measure was anterior–posterior translation between femur and tibia. We were able to demonstrate a significantly higher femoral rollback in the innovative implant group (p < 0.001). The mean rollback of the innovative system was 11.00 mm (95%-confidence interval [CI], 10.77–11.24), of the established system 8.12 mm (95%-CI, 7.84–8.42). This study revealed a significantly increased lateral as well as medial femoral rollback of knees with the innovative prosthesis design. Our intraoperative finding needs to be confirmed using fluoroscopic or radiographic three-dimensional matching under full-weight-bearing conditions after complete recovery from surgery.

Recovery patterns in patients undergoing revision surgery of the primary knee prosthesis

Purpose

Despite good survival rates of revised knee prostheses, little is known about recovery trajectories within the first 12 months after surgery. This retrospective observational study explored recovery trajectories in terms of pain, function and quality of life in patients after revision knee arthroplasty over 12 months.

Methods

Eighty-eight revision knee arthroplasty patients rated changes in daily physical functioning using the anchor question (0: very much worsened; 7: very much improved). Patient reported outcome measures (PROMs) of pain (range 0–10), function (Oxford Knee Score) and quality of life (EQ-5D-3L) were assessed preoperatively, at 3 and 12 months postoperatively. Four recovery trajectories were identified using the anchor question at 3 and 12 months postoperatively: no improvement, late improvement, early improvement, and prolonged improvement. Repeated measures ANOVA was conducted with recovery trajectories as dependent variable and PROM assessments as independent variables.

Results

Sixty percent reported improvement in daily physical functioning at 12 months postoperatively. Age and reason for revision differed between groups. Pain, function and EQ-5D-3L differed between groups over time. Late and prolonged improvement groups improved on all PROMs at 12 months. The early improvement group did not report improvement in daily physical functioning at 12 months, while improvements in function and pain during activity were observed.

Conclusions

Different recovery trajectories seem to exist and mostly match PROMs scores over time. Not all patients may experience beneficial outcome of revision knee arthroplasty. These findings are of importance to provide appropriate information on possible recovery trajectories after revision knee arthroplasty to patients.

Level of evidence

III

Supplementary Information

The online version contains supplementary material available at 10.1186/s40634-021-00436-w.

Good Postoperative Flexion Angle Improves Knee Function and Improvement of Flexion Angle Increases Patient Satisfaction After Total Knee Arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is a well-established procedure for treating knee joint diseases. However, the postoperative range of motion (ROM) varies and is an important indicator of TKA success. Recently, patient-reported outcome measures (PROMs) and patient satisfaction have drawn attention. However, the relationship between ROM and knee function obtained by PROM and satisfaction is not well understood.

METHODS

We retrospectively reviewed the data of 375 patients who underwent 500 primary TKA procedures. We measured the ROM before and after surgery. Knee joint function was evaluated using the Knee Injury Osteoarthritis Outcome Score, a PROM, and patients were classified into good function and poor function groups. Patient satisfaction was evaluated on a 5-graded scale as overall satisfaction, and patients were divided into a satisfied or a dissatisfied group according to the obtained scores. ROM was compared between the 2 groups, then significantly different factors were analyzed using multiple logistic regression analysis. Moreover, cut-off points of ROM for obtaining good function and patient satisfaction were determined using ROC curve analysis.

RESULTS

The postoperative flexion angle had a significant effect on knee function (P < .001). The cut-off value of the postoperative flexion angle for good knee function was 120°. The improvement in flexion angle had a significant effect on patient satisfaction (P = .004). The cut-off value for the improvement in the flexion angle was 5°.

CONCLUSION

The postoperative flexion angle had a significant effect on knee function and improvement in the flexion angle had a significant effect on patient satisfaction.

Weight-bearing knee flexion angle better correlates with patient-reported outcome measures than non-weight-bearing condition in total knee arthroplasty: a three-dimensional analysis study

Background

This study aims to elucidate and compare the relationship between the knee flexion angle and patient-reported outcome measures (PROM) in both non-weight-bearing (NWB) and weight-bearing (WB) conditions.

Methods

This retrospective cohort study included 61 knees (47 patients) who underwent total knee arthroplasty. The knee flexion angle was measured by three conditions: NWB in manual goniometer, NWB in fluoroscopic three-dimensional (3D) analysis and WB in the fluoroscopic 3D analysis. The PROM was evaluated by postoperative 2011 Knee Society Score (2011 KSS) and Knee injury and Osteoarthritis Outcome Score (KOOS). Correlations between the knee flexion angle and PROM was analyzed using Spearman’s correlation coefficient. Additionally, whether the angular difference between NWB and WB correlated with the PROM or not was evaluated.

Results

The NWB knee flexion angle in a goniometer, NWB in 3D analysis, and WB in 3D analysis were 124.6° ± 8.4°, 118.0° ± 10.5°, and 109.5° ± 13.3°, respectively. The angular difference was 8.5° ± 12.8°. No PROM correlation existed in NWB using a goniometer. Moreover, significant positive correlations in 2011 KSS symptoms (r = 0.35) and 2011 KSS functional activities (r = 0.27) were noted in NWB using 3D analysis. Significant positive correlations existed in 2011 KSS symptoms (r = 0.32), 2011 KSS functional activities (r = 0.57), KOOS pain (r = 0.37), KOOS activity of daily living (ADL; r = 0.45), KOOS sports (r = 0.42), and KOOS quality of life (r = 0.36) in WB using 3D analysis. Significant negative correlations were noted in 2011 KSS functional activities (r = − 0.45), KOOS ADL (r = − 0.30), and KOOS sports (r = − 0.38) in angular difference.

Conclusions

The WB knee flexion angle better correlated with PROM compared with NWB by evaluation of 3D analysis. The larger the angular difference existed between NWB and WB, the lower the PROM score.

Early postoperative straight leg raise is associated with shorter length of stay after unilateral total knee arthroplasty

PURPOSE

Shorter length of stay (LOS) after total knee arthroplasty (TKA) is cost-effective. Straight leg raise (SLR) is a common exercise prescribed after TKA, but the significance of early postoperative SLR is unknown. The primary aim of this study is to evaluate the association between early postoperative SLR and LOS. Secondary aims are to explore associations among early postoperative SLR, time to ambulation, and time to stairs climbing and identify factors related to postoperative SLR.

METHODS

888 TKAs (888 knees, 865 patients) performed at a tertiary hospital in 2016 were included for this retrospective study. All TKAs were performed with medial parapatellar approach and tourniquet. Time to events (SLR, ambulation, stair climbing), LOS and factors influencing these events were analysed using a multivariate Poisson regression model and logistic regression.

RESULTS

Patients who performed SLR on postoperative day 1 (POD1) had shorter LOS than those who did not (adjusted Mean Ratio (aMR) = 0.846, p < 0.001), with estimated mean LOS being 3.5 days and 4.1 days, respectively. Performing SLR on POD1 was also associated with shorter time to ambulation (aMR = 0.789; p < 0.001) and stair climbing (aMR = 0.811, p < 0.001). Female gender and higher rest pain on POD1 were associated with delayed postoperative SLR.

CONCLUSION

Performing SLR on POD1 after TKA is associated with shorter LOS, time to ambulation, and time to stair climbing. Early postoperative SLR can prognosticate early recovery and discharge. Optimization of preoperative muscle strength and postoperative pain may be important in early recovery after TKA.

Angiotensin Receptor Blockers Were Not Associated With Decreased Arthrofibrosis After Total Knee Arthroplasty

Stiffness after total knee arthroplasty (TKA) remains a challenging problem. Angiotensin receptor blockers (ARBs) have been associated with decreased muscle fibrosis. The aim of this study was to evaluate whether perioperative use of ARBs was associated with a reduction in arthrofibrosis and manipulation under anesthesia (MUA) in patients undergoing primary TKA at 90 days and 1 year postoperative. In this retrospective study, the authors used a national database to evaluate patients undergoing TKA for primary osteoarthritis from 2007 to 2017. They evaluated patients with filled prescriptions for ARBs within the study time frame and the specific type of ARB and its association with arthrofibrosis and MUA. After adjusting for age, sex, a comorbidity index, and obesity, any ARB or specific ARBs were not associated with a reduction in the rate of arthrofibrosis or MUA after TKA (P≥.05). Male sex, age 55 years or older, and obesity were associated with a reduction in the rate of arthrofibrosis and MUA after TKA (P≤.05). Studies should be performed to evaluate ARBs to see whether there is a more specific role in preventing joint stiffness in certain patient subpopulations following TKA. [Orthopedics. 2021;44(2):e274-e280.].

A high degree of knee flexion after TKA promotes the ability to perform high-flexion activities and patient satisfaction in Asian population

Background

This study investigated whether achieving a higher degree of knee flexion after TKA promoted the ability to perform high-flexion activities, as well as patient satisfaction and quality of life.

Methods

Clinical data on 912 consecutive primary TKA cases involving a single high-flexion posterior stabilized fixed-bearing prosthesis were retrospectively analyzed. Demographic and clinical data were collected, including knee flexion angle, the ability to perform high-flexion activities, and patient satisfaction and quality of life.

Results

Of the cases, 619 (68%) achieved > 130° of knee flexion after TKA (high flexion group). Knee flexion angle and clinical scores showed significant annual changes, with the maximum improvement seen at 5 years and slight deterioration observed at 10 years postoperatively. In the high flexion group, more than 50% of the patients could not kneel or squat, and 35% could not stand up from on the floor. Multivariate analysis revealed that > 130° of knee flexion, the ability to perform high-flexion activities (sitting cross-legged and standing up from the floor), male gender, and bilateral TKA were significantly associated with patient satisfaction after TKA, while the ability to perform high-flexion activities (sitting cross-legged and standing up from the floor), male gender, and bilateral TKA were significantly associated with patient quality of life after TKA.

Conclusions

High knee flexion angle (> 130°) after TKA increased the ease of high-flexion activities and patient satisfaction. The ease of high-flexion activities also increased quality of life after TKA in our Asian patients, who frequently engage in these activities in daily life.

Importance of knee flexion range of motion during the acute phase after total knee arthroplasty

BACKGROUND

We investigate the association with knee flexion range of motion (ROM) during the acute phases and that at 12 months after total knee arthroplasty (TKA). We also clarified the cut-off ROM during the acute phases in predicting the goal of knee flexion ROM at 12 months.

METHODS

In this retrospective study, 193 patients with knee osteoarthritis (female:144 patients, age:73.2 ± 7.7 years) who underwent unilateral TKA at an orthopedic clinic were recruited. They underwent assessments of knee flexion ROM at 5 days, 1 month, and 12 months after TKA. The goal of knee flexion ROM at 12 months after TKA was set at 120°. Single and logistic-regression analyses were performed with the dependent variables including the outcome of the goal of knee flexion ROM at 12 months, and the independent variables included knee flexion ROM at 5 days and 1 month, separately. We calculated the cut-off ROM at 5 days and 1 month for predicting the goal of knee flexion ROM at 12 months with receiver operating curve analysis.

RESULTS

Knee flexion ROM at 5 days and 1 month were significantly associated with the goal of that at 12 months (p < 0.01). The cut-off ROM were 85° at 5 days and 105° at 1 month separately.

CONCLUSIONS

Our results suggest the importance of early improvement in knee flexion ROM after TKA, and that at 1 month postoperatively indicates the likelihood of achievement of the goal of knee flexion ROM at 12 months after TKA.

Changes in knee range of motion after large osteochondral allograft transplantations

BACKGROUND

Our study purpose was to determine if primary osteochondral allograft (OCA) transplant surgeries for large (>4 cm²) single-surface, multisurface, or bipolar articular defects in the knee would be associated with significant gains in knee range of motion (ROM) at ≥1-year follow-up when compared to preoperative ROM.

METHODS

Patients were prospectively enrolled into a dedicated registry to follow outcomes after OCA with or without meniscal allograft transplantation using Missouri Osteochondral Preservation System (MOPS)-preserved allografts. Patients were included if they had surgery to repair at least one osteochondral defect, and when at least one year of ROM data and Visual Analog Scale pain scores were available. Data on complications and reoperations, patient-reported outcome measures, compliance with rehabilitation, revisions, or failures were recorded.

RESULTS

For patients who met inclusion criteria after OCA surgery (n = 75), overall ROM increased from 127.8 ± 17 degrees preoperatively, to 130.5 ± 14 post-operatively. Non-compliance was the largest factor contributing to postoperative ROM lag or loss. Knee manipulation/lysis of adhesion rates were comparable to rates in TKA and ACL procedures (2.96-4.54% for ACL/TKA, 4% for OCAs in the present study).

CONCLUSION

Results suggest that OCA with or without meniscal allograft transplantation in the knee using high-viability grafts, advanced graft cutting and implantation techniques, and procedure-specific rehabilitation protocols can result in consistently successful outcomes in a high percentage (92%) of selected patients. Most patients (95%) can expect to regain, or improve, to "full" functional range of motion (130°) at 1 year after surgery such that highly functional activities can be performed.

LEVEL OF EVIDENCE

Cohort study; Level III.

Maximal flexion and patient outcomes after TKA, using a bicruciate-stabilizing design

INTRODUCTION

Physiological motion after total knee arthroplasty (TKA) should result in a large range of motion, which would lead to good clinical outcomes. An adjusted design of a bicruciate-stabilizing TKA was developed to reproduce physiological motion. The aim of this study was to (1) investigate the maximal knee flexion of this knee system, 1 year post-operatively; (2) determine the clinical and functional improvement and compare the outcomes between patients with and without high maximal flexion; and (3) evaluate the adverse events.

MATERIALS AND METHODS

In this prospective study, 62 patients with osteoarthritis received a bicruciate-stabilizing TKA. Maximum flexion was measured on a lateral X-ray pre- and post-operatively. Clinical and functional scores and the adverse events were reported up until 2 years after surgery.

RESULTS

Pre-operatively, the median (range) maximal flexion was 131.5 (90-153)° and 1 year post-operatively, it was 130 (82-150)°. The results for the clinical scores showed an improvement between pre-operative values and post-operative values. The Kujala score and Knee Osteoarthritis Outcome Score (KOOS) symptoms, sport and quality of life score were better in patients with high maximal flexion (≥ 125°). Ten (serious) adverse device events were reported.

CONCLUSIONS

In conclusion, the bicruciate-stabilizing TKA obtained a maximal flexion comparable to the flexion pre-operatively and resulted in good clinical and functional outcomes. Patients with high flexion ability seem to perform better on clinical and functional outcomes. Furthermore, the adjusted design of the bicruciate-stabilizing TKA reduced the number of adverse events.

LEVEL OF EVIDENCE

Prospective cohort study, Level II.

Stiffness After Total Knee Arthroplasty: Is It a Result of Spinal Deformity?

BACKGROUND

There are no studies to date analyzing the effect of spinal malalignment on outcomes of total knee arthroplasty (TKA). Knee flexion is a well-described lower extremity compensatory mechanism for maintaining sagittal balance with increasing spinal deformity. The purpose of this study was to determine whether a subset of patients with poor range of motion (ROM) after TKA have unrecognized spinal deformity, predisposing them to knee flexion contractures and stiffness.

METHODS

We retrospectively evaluated a consecutive series of patients who underwent manipulation under anesthesia (MUA) for poor ROM after TKA. Using standing full-length biplanar images, knee alignment and spinopelvic parameters were measured. Patients were stratified by pelvic incidence minus lumbar lordosis as a measure of spinal sagittal alignment with a mismatch of ≥10° defined as abnormal, and we calculated the incidence of sagittal spinal deformity.

RESULTS

Average ROM before MUA was extension 3° and flexion 83°. About 62% of patients had a pelvic incidence minus lumbar lordosis mismatch of ≥10°. In the spinal deformity group, post-MUA ROM was improved for flexion only, whereas both flexion and extension were improved in the nondeformity group.

CONCLUSION

Compensatory knee flexion because of sagittal spinal deformity may predispose to poor ROM after TKA. Patients with clinical suspicion should be worked up preoperatively and counseled accordingly.

Physical outcome measures: The role of strength and range of motion in orthopaedic research

Outcome measures are the indispensable mean through which different interventions are compared in research. The increase in volume that orthopaedic research has experienced in the last years has provided an extensive list of outcomes to choose from. Historically, attention has been focused mainly in morbidity as well as physician reported clinical outcomes, however there is a trend towards the use of patient reported outcomes. We intent to review the inherent characteristics and current applicability of two of the most representative physical outcome measures used in orthopaedics: Range of Motion (ROM) and Strength.

Diabetes mellitus does not increase the risk of knee stiffness after total knee arthroplasty: a meta-analysis of 7 studies including 246 053 cases

Purpose

Methods

Results

Conclusion

Level of evidence

Effect of insert material on forces on quadriceps, collateral ligament, and patellar tendon after rotating platform mobile-bearing total knee arthroplasty

BACKGROUND

There is a gradual increase in the number of patients for total knee arthroplasty (TKA), and TKA demonstrates reliable clinical outcomes. The orthopaedic biomaterials community continuously attempted over the past decades to improve the longevity of UHMWPE in TKA by using various improved technologies. Polyetheretherketone (PEEK) and carbon fiber reinforced-PEEK(CFR-PEEK) are suggested as potential tibial insert materials to replace UHMWPE in some applications. The aim of this study involves evaluating the biomechanical effects of UHMWPE and CFR-PEEK tibial materials on mobile-bearing TKA.

METHODS

The finite element (FE) model was obtained by conducting computed tomography and magnetic resonance imaging. The FE investigation included three types of loading conditions corresponding to the loads used in the experiments for FE model validation and model predictions under deep-knee bend loading conditions. We investigated forces on quadriceps, collateral ligament and patellar tendon with UHMWPE and CCFR-PEEK tibial insert materials under the deep-knee-bend condition.

RESULTS

Quadriceps force decreased with flexion for CFR-PEEK when compared to that for UHMWPE. A similar trend was observed in terms of the patellar tendon force. An opposite trend was observed in the collateral ligament. Medial collateral ligament force in the CFR-PEEK exceeded that in the UHMWPE, and lateral collateral ligament force in the UHMWPE exceeded that in the CFR-PEEK.

CONCLUSION

The CFR-PEEK represents an alternative insert material given its superior biomechanical effect after mobile-bearing total knee arthroplasty. However, a balance between the medial and lateral ligaments is considered as an important factor in the CFR-PEEK tibial insert due to its opposite biomechanical effect.

Mediolateral coronal laxity does not correlate with knee range of motion after total knee arthroplasty

INTRODUCTION

It remains controversial whether coronal laxity after total knee arthroplasty (TKA) is a critical factor in determining clinical outcomes such as knee range of motion (ROM). The purpose of this study was to evaluate the correlation between postoperative ROM and coronal laxity, which was defined as the angular motion from the neutral, unloaded position to the loaded position, in patients with medial knee osteoarthritis undergoing TKA.

MATERIALS AND METHODS

Preoperative and 1-year postoperative coronal laxity were assessed using radiographs by applying a force of 150 N with an arthrometer. A consecutive series of 204 knees was examined. A knee was defined as clinically "balanced" when the difference between medial and lateral laxity was 3° or less. Active ROM was measured using a goniometer. Values were expressed as median values.

RESULTS

The ROM was 105° preoperatively and 110° postoperatively, with the correlation being weak (r = 0.372, p < 0.001) between the periods. The total laxity also revealed a weak correlation (r = 0.270, p < 0.001) between the periods. Preoperative laxity was significantly larger (4° vs. 3°) on the medial side (p < 0.001) and postoperative laxity was larger (4° vs. 3°) laterally (p = 0.001). There was no significant correlation between postoperative ROM and laxity pre- and postoperatively. Additionally, there were no differences in ROM between the balanced and unbalanced groups in the pre- and postoperative periods.

CONCLUSIONS

This study indicated that mediolateral coronal laxity in patients with an osteoarthritic knee did not correlate with knee ROM after TKA when 3°-4° of laxity in the medial and lateral orientations was maintained.

Tibiofemoral conformity variation offers changed kinematics and wear performance of customized posterior-stabilized total knee arthroplasty

PURPOSE

Posterior-stabilized (PS)-total knee arthroplasty (TKA) can be applied in any of several variations in terms of the tibiofemoral conformity and post-cam mechanism. However, previous studies have not evaluated the effect of the condylar surface radii (tibiofemoral conformity) on wear in a customized PS-TKA. The present study involved evaluating the wear performance with respect to three different conformities of the tibiofemoral articular surface in a customized PS-TKA by means of a computational simulation.

METHODS

An adaptive computational simulation method was developed that conduct wear simulation for tibial insert to predict kinematics, weight loss due to wear, and wear contours to results. Wear predictions using computational simulation were performed for 5 million gait cycles with force-controlled inputs. Customized PS-TKA designs were developed and categorized as conventional conformity (CPS-TKA), medial pivot conformity (MPS-TKA), and anatomical conformity (APS-TKA). The post-cam design in the customized PS-TKA is identical. We compared the kinematics, contact mechanics, and wear performance.

RESULTS

The findings revealed that APS-TKA exhibited the highest internal tibial rotation relative to other TKA designs. Additionally, the higher contact area led to there being less contact stress although it did not directly affect the wear performance. Specifically, MPS-TKA exhibited the lowest volumetric wear.

CONCLUSIONS

The results of the present study showed that tibiofemoral articular surface conformity should be considered carefully in customized PS-TKA design. Different wear performances were observed with respect to different tibiofemoral conformities. Even though APS-TKA exhibited an inferior wear performance compared to MPS-TKA, it proved to be better in terms of kinematics so its functionality may be improved through the optimization of the tibiofemoral articular surface conformity. Additionally, it should be carefully designed since any changes may affect the post-cam mechanism.

Posterior condylar offset influences the intraoperative soft tissue balance during posterior-stabilized total knee arthroplasty

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.

Variability in static alignment and kinematics for kinematically aligned TKA

BACKGROUND

Total knee arthroplasty (TKA) significantly improves pain and restores a considerable degree of function. However, improvements are needed to increase patient satisfaction and restore kinematics to allow more physically demanding activities that active patients consider important. The aim of our study was to compare the alignment and motion of kinematically and mechanically aligned TKAs.

METHODS

A patient specific musculoskeletal computer simulation was used to compare the tibio-femoral and patello-femoral kinematics between mechanically aligned and kinematically aligned TKA in 20 patients.

RESULTS

When kinematically aligned, femoral components on average resulted in more valgus alignment to the mechanical axis and internally rotated to surgical transepicondylar axis whereas tibia component on average resulted in more varus alignment to the mechanical axis and internally rotated to tibial AP rotational axis. With kinematic alignment, tibio-femoral motion displayed greater tibial external rotation and lateral femoral flexion facet centre (FFC) translation with knee flexion than mechanical aligned TKA. At the patellofemoral joint, patella lateral shift of kinematically aligned TKA plateaued after 20 to 30° flexion while in mechanically aligned TKA it decreased continuously through the whole range of motion.

CONCLUSIONS

Kinematic alignment resulted in greater variation than mechanical alignment for all tibio-femoral and patello-femoral motion. Kinematic alignment places TKA components patient specific alignment which depends on the preoperative state of the knee resulting in greater variation in kinematics. The use of computational models has the potential to predict which alignment based on native alignment, kinematic or mechanical, could improve knee function for patient's undergoing TKA.

Kneeling and standing up from a chair as performance-based tests to evaluate knee function in the high-flexion range: a randomized controlled trial comparing a conventional and a high-flexion TKA design

Background

We compared the functional outcome between conventional and high-flexion total knee arthroplasty (TKA) using kneeling and sit-to-stand tests at 1 year post-operative. In addition, the patient’s daily functioning, pain and satisfaction were quantified using questionnaires.

Methods

We randomly assigned 56 patients to receive either a conventional or a high-flexion TKA. Primary outcomes were maximum flexion angle and maximum thigh-calf contact measured during kneeling at 1 year post operatively. Secondary outcomes were the angular knee velocity and ground reaction force ratio measured during sit-to-stand performance tests, and questionnaires.

Results

At one year post-operative, maximum knee flexion during kneeling was higher for the high-flexion TKA group (median 128.02° (range 108–146)) compared to the conventional TKA group (119.13° (range 72–135)) (p = 0.03). Maximum thigh-calf contact force was higher for the high flexion TKA group (median 17.82 N (range 2.98–114.64)) compared to the conventional TKA group (median 9.37 N (range 0.33–46.58))(p = 0.04). The sit-to-stand tests showed a significantly higher angular knee velocity in the conventional TKA group (12.12 rad/s (95%CI 0.34–23.91); p = 0.04). There were no significant differences between groups in ground reaction force ratios and patient-reported outcome scores.

Conclusion

Although no differences were found in patient-reported outcome scores, differences in performance-based tests were clearly apparent. Standing up from a chair at 90° of knee flexion appeared to be easier for the conventional group. The kneeling test revealed significantly higher weight-bearing knee flexion for the high-flex group. Hence, if kneeling is an important activity for a patient a high-flex design may be recommendable.

Trial registration

The study was retrospectively registered in ClinicalTrials.gov under identifier NCT00899041 (date of registration: May 11, 2009).

What is the Relationship Between Patients’ And Clinicians’ Reports of the Outcomes of Elective Surgery?

Objectives

To identify studies in which patients’ and clinicians’ reports of health status and complications of one of four elective operations - hip and knee replacement, varicose vein surgery and groin hernia repair - are reported, and to describe the associations that have been reported between clinicians’ and patients’ reports.

Methods

Systematic search of several bibliographic databases and review of citations of articles meeting inclusion criteria. A narrative summary of the findings was conducted.

Results

Most of the 62 studies of health status identified were for hip (23) or knee (33) disease. The literature on complications was even more limited with 12 studies of surgical site infection, one for urinary tract infection and none for lower respiratory tract infections. Procedure-specific complications were restricted to one for arthroplasties and three for hernia repair. Despite considerable variation in the findings of studies, some clear patterns emerge, albeit they are largely based on arthroplasty. Patients’ and clinicians’ views of health status generally correlate moderately (0.5-0.6) when both are reporting on the same dimension of health status. Inevitably this is confined to disability, though patients’ and clinicians’ reports of symptoms are also moderately correlated. In contrast, comparisons of different dimensions, such as patients’ reports of disability and clinicians’ reports of impairment, result in poor correlation (0.3). There is huge variation in the way postoperative complications are measured which limits the extent to which an overview can be undertaken. Despite that, moderate to strong correlations have been reported between patients’ and clinicians’ views of complications.

Conclusions

Patients’ views of their level of disability reflect clinicians’ views and can be relied upon to assess this dimension of health status. In addition, patients are the ‘gold standard’ judges of symptoms and quality of life. Given these findings, clinicians, provider managers, commissioners and politicians can be confident that patients’ reports provide an accurate indication of the outcome of elective surgery.

Increased Range of Motion Is Important for Functional Outcome and Satisfaction After Total Knee Arthroplasty in Asian Patients

BACKGROUND

Although range of motion (ROM) is considered as an important factor for good outcome after total knee arthroplasty (TKA), the association of the degree of ROM with functional outcome and patient satisfaction is debated. We, therefore, investigated whether increased ROM would affect functional outcome and patient satisfaction after TKA in Asian patients.

METHODS

We reviewed 630 patients who underwent primary TKA with minimum 2-year follow-up. Clinical outcomes were evaluated by Knee Society (KS) score, Western Ontario and McMaster Universities osteoarthritis index, and high-flexion knee score. Patient satisfaction was evaluated using a validated questionnaire. The association of ROM and change in ROM (cROM) with clinical outcomes and satisfaction were analyzed using partial correlation analysis and multiple median regression analysis.

RESULTS

All functional scores showed significant correlation with postoperative ROM (r = 0.129, P = .001 in Knee Society score; r = -0.101, P = .012 in Western Ontario and McMaster Universities osteoarthritis index; r = 0.183, P < .001 in high-flexion knee score). cROM correlated with satisfaction (r = 0.192, P = .005). Postoperative ROM and cROM were revealed as predisposing factors affecting function outcome using multivariable regression analysis. cROM was found as a predisposing factor affecting satisfaction.

CONCLUSIONS

Based on the results of this study, ROM positively associated with functional outcome and cROM positively associated with patient satisfaction after TKA. These findings suggest that increased ROM after TKA is an important factor for functional outcome and satisfaction in Asian patients.

Does a new implant design with more physiological kinematics provide better results after knee arthroplasty?

BACKGROUND

Improved knee kinematics is one of the major goals to obtain better satisfaction after total knee arthroplasty. This study examined whether a guided motion knee design improves functional outcome and satisfaction as compared to a conventional design.

METHODS

In a retrospective manner, from January 2005 to December 2008, patients with two different kinematic TKA designs were enrolled. The 150 patients were divided into two groups: guided motion group (77) with kinematic design (Journey) and control group (73) with no kinematic design (LCS). All the patients had the same surgical technique and postoperative protocols. The functional and radiographic results were interpreted with the Hospital for Special Surgery (HSS) knee score and WOMAC score.

RESULTS

After a mean follow-up of 84.2months, the guided motion group had higher mean postoperative range of motion (p=0.022), functional status in the WOMAC function subscale (p=0.002), but had higher residual pain in the WOMAC pain subscale (p=0.018 and p=0.013) and higher iliotibial band syndrome incidence (6.6% vs 0%; p=0.02). There were no significant differences in HSS score between the two groups. No differences were seen between groups in patient satisfaction in the WOMAC total score (p=0.46) and survival rate.

CONCLUSION

The guided motion design can improve functional status according to WOMAC but not to HSS knee scores. Poorer pain scores and no higher patient satisfaction were observed with this kinematic design.

Range of movement correlates with the Oxford knee score after total knee replacement: A prediction model and validation

BACKGROUND

Patient reported outcome measures are widely used in the evaluation of outcomes after Total Knee Replacement (TKR) in joint registries and large studies. The aim of this study was to assess the relationship between the Oxford knee score (OKS) and range of motion (ROM) after TKR, and to construct and validate prediction models of ROM from the measured OKS.

METHODS

Eight hundred sixty patients reviewed five years postoperatively and 273 patients reviewed nine to 10 years postoperatively completed an OKS. Of these, 808 (94%) and 226 (83%) patients, respectively, had a complete dataset (knee extension and ROM) and formed the study cohort.

RESULTS

Regression analysis demonstrated a significant correlation between the OKS and ROM (r=0.38, p<0.001) after adjusting for other confounding variables (age, sex, body mass index, and knee extension). A prediction model was constructed and validated using a second cohort of 226 patients at nine to 10 years after their TKR. Intraclass correlation demonstrated good reliability (r=0.60, 95% CI 0.47 to 0.69) between predicted and actual measured ROM for this group. However, when the OKS is used in isolation the reliability of the predicted ROM is diminished (intraclass correlation r=0.41, 95% CI 0.24 to 0.55).

CONCLUSIONS

The OKS is an independent predictor of ROM after TKR. It is also possible to predict ROM from the OKS, but the reliability of this is improved when other independent predictors such as age, gender, body mass index (BMI) and degree of knee extension are also acknowledged.

Functional versus patient-reported outcome of the bicruciate and the standard condylar-stabilizing total knee arthroplasty

INTRODUCTION

The purpose of this retrospective comparative analysis in patients undergoing primary total knee arthroplasty (TKA) was to evaluate whether different TKA implant design would influence patient-rated outcomes, functioning, and range of motion (ROM). A secondary purpose of this study was to test for relationships between the patient-rated outcomes and the passive ROM.

MATERIALS AND METHODS

Thirty-one patients who had a primary bicruciate stabilized TKA performed between May 2010 and November 2012 were retrospectively reviewed and compared with a cohort of 30 patients who had condylar-stabilizing TKA during the same period.

RESULTS

No significant differences were observed between the two groups with respect to preoperative demographic characteristics, ROM and radiographic knee alignment. At a mean follow-up of 37 months (SD 7), the Triathlon group had higher mean Knee Injury and Osteoarthritis Outcome Score (KOOS) score in all subscales and a higher Knee Society Score (KSS) score than the Journey group. This difference was statistically significant for the KOOS subscales of pain (p = 0.0099) and activities of daily living (ADL) (p = 0.0003), as well as the KSS score (p = 0.03846). The ROM was significantly higher in the Journey group when compared to the Triathlon group (p = 0.0013). No significant correlation was observed between the ROM and KOOS pain, QOL and ADL subscores and KSS score.

CONCLUSIONS

Postoperative knee ROM and patient perception of knee function after primary TKA can be affected by the different prosthetic designs. However, functionality afforded by the bicruciate TKA is not equivalent to patient satisfaction.

LEVEL OF EVIDENCE

III.

Are the Current Outcome Measurement Tools Appropriate for the Evaluation of the Knee Status in Deep Flexion Range?

We determined whether current outcome measurement tools are appropriate for the evaluation of the knee status in deep flexion range after TKA. Patients (n = 604) with more than 120° of knee flexion were evaluated by Knee Society score, WOMAC, and high flexion knee score (HFKS). The appropriateness of measurement tools was analyzed by correlation analyses and group comparisons (group 1: 120°-129°, group 2: 130°-139°, group 3: 140°-150°). HFKS showed stronger correlation with knee flexion compared with other scores. While other scores only differentiated between groups 2 and 3, HFKS could differentiate among groups 1, 2 and 3. These findings suggest that employment of proper outcome measurement tool is needed to evaluate and differentiate the knee status in deep flexion range after TKA.

Functional Results of the ROCC® Mobile Bearing Knee. 602 Cases at Midterm Follow-Up (5 to 14 Years)

We report midterm results of a prospective continuous cohort of ROCC® Total Knee Arthroplasties (TKA). Between 2001 and 2008, all primary TKA patients (n=500) received 602 ROCC saddle-shaped rotating platform TKAs. Mean follow-up was 7.5 years (5-13) (>10 years in 123 knees). 82 patients (93 knees) died; 20 patients (21 knees) were lost to follow-up. Active flexion improved from 119° (10°-150°) to 127° (90°-155°) and Knee Society knee score from 39±11 to 94±9. Two knees were reoperated for aseptic loosening: Kaplan-Meier 14-year survivorship with aseptic loosening as end-point was 99.4% (95% CI, 99.8-100). UCLA mean score increased from 3.8/10 at baseline to 7.3/10 at last FU, 91% recovering pre-disease activity, and 27% with UCLA score ≥8/10. ROCC TKA demonstrated solid midterm survivorship without activity-related complications.

LEVEL OF EVIDENCE

Therapeutic, Level IV.

Quality of life after bilateral total knee arthroplasty determined by a 3-year longitudinal evaluation using the Japanese knee osteoarthritis measure

BACKGROUND

Recently, the Japanese knee osteoarthritis measure (JKOM), a new disease-specific and patient-derived quality of life (QOL) measure, has been developed. The objectives of this study were to longitudinally evaluate QOL assessed by JKOM and objective outcomes including knee society score (KSS), range of motion (ROM), and timed up and go test (TUG) of patients who underwent bilateral total knee arthroplasties (TKAs) for osteoarthritis; to evaluate correlations between JKOM and those objective outcomes; and to test our hypothesis that increased maximum flexion leads to better JKOM.

METHODS

Forty patients with bilateral TKAs and ≥ 3-year follow-up were included. There were 35 female and 5 male patients with a mean patient age of 74 years. They were evaluated preoperatively (Pre), 5-29 months after unilateral TKA (after U), 12-21 months after bilateral TKAs (1 year after B), 24-34 months after bilateral TKAs (2 years after B), and 36-46 months after bilateral TKAs (3 years after B) using JKOM, KSS, TUG, and ROM.

RESULTS

Improvements in JKOM and TUG were statistically significant between "Pre" and "after U", and between the "after U" and "1 year after B". Improvements in the KSS function score were statistically significant between "after U" and "1 year after B" but not between "Pre" and "after U". The improvements in the JKOM scores, the KSS function score, and TUG did not increase after the 1-year follow-up but was maintained at "3 years after B". The maximum flexion value did not change among the evaluation time points. There were statistically significant correlations between JKOM with KSS and TUG but not with ROM.

CONCLUSIONS

There were statistically significant correlations between JKOM with KSS and TUG but not with ROM. Therefore, our hypothesis was false even in a Japanese population.

Variations in morphological characteristics of prostheses for total knee arthroplasty leading to kinematic differences

BACKGROUND AND PURPOSE

The aim of this study is to compare kinematics during weight-bearing deep knee-bending motion in patients after bilateral total knee arthroplasty (TKA) of two types: 1) a conventional ScorpioFlex prosthesis and 2) a contemporary redesigned non-restrictive-geometry (NRG) prosthesis installed by the same surgeon.

METHODS

We enrolled 15 patients who underwent conventional ScorpioFlex posterior-stabilised TKA in one knee and contemporary NRG TKA on the contralateral side (the same surgeon). During fluoroscopic examination, each patient performed weight-bearing deep knee bending. Motions among all components were analysed using a two- to three-dimensional registration technique.

RESULTS

The mean maximum flexion was 108° (SD 8) and 120° (SD 9) after ScorpioFlex and NRG TKAs, respectively; there were statistically significant differences between the groups. From extension to maximal flexion, the medial condyle translated by 4.8mm (SD 1.2) and 5.4mm (SD 2.4) posteriorly after ScorpioFlex TKA and NRG TKA, respectively. The lateral femoral condyle moved 8.4mm (SD 1.5) and 12.2mm (SD 2.1) posteriorly after ScorpioFlex TKA and NRG TKA, respectively. There were no significant differences in medial condyle translation between the groups except for the lateral condyle. The total amount of tibial axial rotation during extension to flexion was 5.1° (SD 1.8) after ScorpioFlex and 13.2° (SD 3.4) after NRG TKAs; there were statistically significant differences between the groups.

CONCLUSIONS

NRG resulted in much better maximum flexion, lateral condyle movement and tibial internal rotation than did ScorpioFlex TKAs. The observed kinematic differences are most likely caused by variations in the morphological characteristics of the two implants.

Geometric variable designs of cam/post mechanisms influence the kinematics of knee implants

PURPOSE

Reproducing the femoral rollback through specially designed mechanism in knee implants is required to achieve full knee function in total knee arthroplasty. Most contemporary implants use cam/post mechanism to replace the function of Posterior Cruciate Ligament. This study was aimed to determine the most appropriate cam and post designs to produce normal femoral rollback of the knee.

METHODS

Three different cams (triangle, ellipse, and circle) and three different posts (straight, convex, concave) geometries were considered in this study and were analysed using kinematic analyses. Femoral rollback did not occur until reaching 50° of knee flexion. Beyond this angle, two of the nine combinations demonstrate poor knee flexion and were eliminated from the study.

RESULTS

The combination of circle cam with concave post, straight post and convex post showed 15.6, 15.9 and 16.1 mm posterior translation of the femur, respectively. The use of ellipse cam with convex post and straight post demonstrated a 15.3 and 14.9 mm femoral rollback, whilst the combination of triangle cam with convex post and straight post showed 16.1 and 15.8 mm femoral rollback, respectively.

CONCLUSION

The present study demonstrates that the use of circle cam and convex post created the best femoral rollback effect which in turn produces the highest amount of knee flexion. The findings of the study suggest that if the design is applied for knee implants, superior knee flexion may be possible for future patients.

LEVEL OF EVIDENCE

IV.

The influence of the tibial slope on intra-operative soft tissue balance in cruciate-retaining and posterior-stabilized total knee arthroplasty

PURPOSE

This study aims to make clear the influence of the tibial slope on intra-operative soft tissue balance measurements using a tensor in cruciate-retaining and posterior-stabilized total knee arthroplasty (TKA).

METHODS

Forty patients with osteoarthritis of the knee received TKAs (20 cruciate-retaining TKAs and 20 posterior-stabilized TKA). Soft tissue balance was measured using an offset type tensor at 0, 10, 45, 90, 135 degrees of knee flexion. The tibial slopes were measured by post-operative lateral radiograph. The correlation between the tibial slope and values of soft tissue balance were assessed.

RESULTS

Joint component gap at 90° (R = 0.537, p < 0.01) and 135° (R = 0.463, p < 0.05) of flexion and joint component gap change value of 90-0° (R = 0.433, p < 0.05) showed positive correlations with tibial slope in posterior-stabilized TKA. There was no relationship between the tibial slope and the value of soft tissue balances in cruciate-retaining TKA.

CONCLUSIONS

In the present study, we confirmed that increasing the tibial slope resulted in a larger flexion gap compared to extension gap in posterior-stabilized TKA. Surgeons should be aware that increasing the tibial slope is one factor responsible for widening the flexion-extension gap difference in posterior-stabilized TKA.

Can TKA design affect the clinical outcome? Comparison between two guided-motion systems

PURPOSE

In a retrospective comparative analysis in patients undergoing primary guided-motion total knee arthroplasty (TKA), the authors have evaluated whether different TKA implant design would influence the clinical and functional outcomes.

METHODS

Between 2007 and 2009, 227 computer-assisted primary TKAs were performed in 219 consecutive patients. Patients received one of the two different fixed-bearing guided-motion TKA designs assisted by navigation surgery: the Scorpio Non-Restrictive Geometry (NRG) knee system and the Journey Bi-Cruciate Stabilized (BCS) knee systems.

RESULTS

Data were available for 180 patients (187 knees). No significant differences were observed between the two groups with respect to preoperative demographic characteristics, range of motion (ROM) and radiographic knee alignment. At a mean follow-up of 29 months, the Journey BCS group had higher mean Knee Injury and Osteoarthritis Outcome Score (KOOS) in all subscales and a greater ROM than the Scorpio NRG group. This difference was statistically significant for the KOOS subscales of pain (p = 0.007) and knee-related quality of life (p = 0.045), as well as for postoperative ROM (p = 0.018). Considering the overall complications, 1 patient of Scorpio NRG group (0.5%) and 5 in Journey BCS (2.7%) had stiffness. Anterior knee pain was reported in 4 cases of Scorpio NRG group (2.1%). In the Journey BCS group were observed 2 cases (1.1%) of frontal plane instability and 1 case (0.5%) of synovitis pain.

CONCLUSIONS

The bearing geometry and kinematic pattern of different guided-motion prosthetic designs can affect the clinical-functional outcome and complications type in primary TKA.

LEVEL OF EVIDENCE

Clinical study, Level III.

Anteroposterior translation does not correlate with knee flexion after total knee arthroplasty

BACKGROUND

Stiffness after a TKA can cause patient dissatisfaction and diminished function, therefore it is important to characterize predictors of ROM after TKA. Studies of AP translation in conscious individuals disagree whether AP translation affects maximum knee flexion angle after implantation of a highly congruent sphere and trough geometry PCL-substituting prosthesis in a TKA.

QUESTIONS/PURPOSES

We investigated whether AP translation correlated with maximum knee flexion angle (1) in patients who were awake, and (2) who were under anesthesia (to minimize the effects of voluntary muscle contraction) in a TKA with implantation of a PCL-substituting mobile-bearing prosthesis.

METHODS

AP translation was examined under both conditions in 34 primary TKAs. Measurements under anesthesia were performed when the patients were having anesthesia for a contralateral TKA. Awake measurements were made within 4 days of that anesthetic session in patients who had no residual sedative effects. The average postoperative interval for the index TKA flexion measurements was 23 months (range, 6-114 months). AP translation was evaluated at 75° flexion using an arthrometer.

RESULTS

There was no correlation between postoperative maximum knee flexion and AP translation at 75° during consciousness. There was no correlation between postoperative maximum knee flexion and AP translation under anesthesia.

CONCLUSION

AP translation at 75° flexion did not correlate with postoperative maximum knee flexion in either awake or anesthetized patients during a TKA with implantation of a posterior cruciate-substituting prosthesis.

Errors in visual estimation of flexion contractures during total knee arthroplasty

AIM: To quantify and reduce the errors in visual estimation of knee flexion contractures during total knee arthroplasty (TKA).

METHODS: This study was divided into two parts: Quantification of error and reduction of error. To quantify error, 3 orthopedic surgeons visually estimated preoperative knee flexion contractures from lateral digital images of 23 patients prior to and after surgical draping. A repeated-measure analysis of variance was used to compare the estimated angles prior to and following the placement of the surgical drapes with the true knee angle measured with a long-arm goniometer. In an effort to reduce the error of visual estimation, a dual set of inclinometers was developed to improve intra-operative measurement of knee flexion contracture during TKA. A single surgeon performed 6 knee extension measurements with the device during 146 consecutive TKA cases. Three measurements were taken with the desired tibial liner trial thickness, and 3 were taken with a trial that was 2 mm thicker. An intraclass correlation coefficient (ICC) was calculated to assess the test-retest reliability for the 3 measurements taken with the desired liner thickness, and a paired t test was used to determine if the knee extension measurements differed when a thicker tibial trial liner was placed.

RESULTS: The surgeons significantly overestimated flexion contractures in 23 TKAs prior to draping and significantly underestimated the contractures after draping (actual knee angle = 6.1°± 6.4°, pre-drape estimate = 6.9°± 6.8°, post-drape estimate = 4.3°± 6.1°, P = 0.003). Following the development and application of the measurement devices, the measurements were highly reliable (ICC = 0.98), and the device indicated that 2.7°± 2.2° of knee extension was lost with the insertion of a 2 mm thicker tibial liner. The device failed to detect a difference in knee extension angle with the insertion of the 2 mm thicker liner in 9/146 cases (6.2%).

CONCLUSION: We determined the amount of error associated with visual estimation of knee flexion contractures, and developed a simple, reliable device and method to improve feedback related to sagittal alignment during TKA.

Do patients care about higher flexion in total knee arthroplasty? A randomized, controlled, double-blinded trial

Background

Little information exists to support that patients care about flexion beyond what is needed to perform activities of daily living (ADL) after Total knee arthroplasty (TKA). The purpose of this study was to investigate if the achievement of a higher degree of knee flexion after TKA would result in a better patient perceived outcome.

Methods

The study is a randomized, double-blinded, controlled trial in which 36 patients (mean age: 67.2 yrs) undergoing one-stage bilateral TKA randomly received a standard cruciate-retaining (CR) TKA in one knee and a high-flex posterior-stabilized (PS) TKA in the contra lateral knee. At follow-up ROM, satisfaction, pain, “feel” of the knee and the abilities in daily activities were assessed.

Results

At 1-year follow-up we found an expected significantly higher degree of knee flexion of 7° in the high-flex knees (p = 0.001). The high-flex TKA’s showed a mean active flexion of 121°. In both TKA’s the median VAS pain score was 0, the median VAS satisfaction score was 9, and the median VAS score of the patient “feel” of the knee was 9 at 1-year follow-up. Further, there were no significant differences between the knees in the performance of daily activities.

Conclusions

As expected the high-flex TKA showed increased knee flexion, but no significant differences in the patient perceived outcomes were found. This suggests little relevance to the patients of the difference in knee flexion – when flexion is of this magnitude – as pain free ROM and high patient satisfaction were achieved with both TKA’s.

Trial registration

ClinicalTrials.gov: NCT00294528

Postoperative alignment and ROM affect patient satisfaction after TKA

BACKGROUND

Patient satisfaction has increasingly been recognized as an important measure after total knee arthroplasty (TKA). However, we do not know yet how and why the patients are satisfied or dissatisfied with TKA.

QUESTIONS/PURPOSES

We asked: (1) After TKA, how satisfied are patients and which activities were they able to do? (2) Are patient-derived scores related to physician-derived scores? (3) Which factors affect patient satisfaction and function?

METHODS

We retrospectively evaluated 375 patients who had undergone 500 TKAs between February 22, 2000 and December 1, 2009. We sent a questionnaire for The 2011 Knee Society Knee Scoring System to the patients. We determined the correlation of patient- and physician-derived scores and factors relating to the five questions relating to satisfaction and the 19 questions relating function. The minimum followup was 2 years (mean, 5 years; range, 2-11 years).

RESULTS

The mean score for symptoms was 19 (74%), 23 (59%) for patient satisfaction, 10 (64%) for patient expectations, and 53 (53%) for functional activities. We found a poor correlation between the patient-derived and the physician-derived scores. Old age and varus postoperative alignment negatively correlated with the satisfaction. Varus alignment and limited range of motion (ROM) negatively correlated with the expectation. Old age, rheumatoid arthritis, and limited ROM negatively correlated with the functional activities.

CONCLUSIONS

Most patients did not report symptoms, but they experienced difficulty with activities of daily living after TKA. Patient satisfaction is difficult to measure, but avoiding varus alignment and achieving better ROM appear to be important for increasing satisfaction and meeting expectations.

Outcomes of the different types of total knee arthroplasty with the identical femoral geometry

Purpose

There are controversies around the role of the posterior cruciate ligament and the effect of design modifications for high flexion in total knee arthroplasty (TKA). So, we compared the clinical outcomes of the cruciate retaining (CR), posterior stabilized (PS), and high flexion posterior stabilized (F-PS) designs in TKA with identical femoral geometry.

Materials and Methods

One hundred seventy nine knees with 3 different types of prostheses after a minimum 5-year follow-up were enrolled in this retrospective study: 45 with CR, 40 with PS and 94 with F-PS. The mean ages of these groups were 65.7, 67.2, and 67.5, and the mean durations of follow-up were 8.1, 8.0, and 6.8 years, respectively. We compared the range of motion, functional outcomes, and radiographic measurements at the 2-year follow-up and last follow-up.

Results

The maximal flexion angle was significantly lower in the CR group than the F-PS group at the 2-year follow-up. However, there was no significant difference at the last follow-up. Functional outcomes and survival rate of the three groups were similar at the last follow-up.

Conclusions

Three different types of TKAs (CR, PS and F-PS) with identical femoral geometry showed similar mid-term outcomes with regard to the range of motion, functional outcomes and survival rate.

Measured flexion following total knee arthroplasty

Postoperative flexion is an important factor in the outcome of total knee arthroplasty. Although normal activities of daily living require a minimum of 105° to 110° of flexion, patients from non-Western cultures often engage in activities such as kneeling and squatting that require higher flexion. The desire to achieve greater flexion serves as the driving force for prosthetic modifications, including high-flexion designs. Techniques used to measure knee flexion and knee position during measurement are not often described or are different depending on the examiner. The purpose of this study was to compare active (self) and passive (assisted) flexion after successful total knee arthroplasty for 5 prostheses (2 standard and 3 high-flexion) using clinical (goniometer) and radiographic (true lateral radiograph) measurement techniques by different independent examiners.At a mean follow-up of 2.7 years (range, 1-5.6 years), a total of 108 patients (144 total knee arthroplasties) had completed the study. Mean postoperative active flexion was 111° clinically and 109° radiographically for the standard designs and 114° clinically and 117° radiographically for the high-flexion designs. Adding passive flexion increased flexion to 115° clinically and 117° radiographically for the standard designs and 119° clinically and 124° radiographically for the high-flexion designs. Flexion differences between the 2 measurement techniques (active vs passive and clinically vs radiographically) were statistically significant (P<.05). These findings demonstrate the importance of describing how flexion is measured in studies and understanding how the method of measurement can affect the findings.

Improvements in knee range and symptomatic and functional behavior after knee arthroplasty based on preoperative restriction in range

Recovery of knee range and Oxford Knee Score post knee arthroplasty based on preoperative knee range is described. A total of 191 patients recruited across 5 hospitals were assessed preoperatively, at 8 weeks postoperatively and 1 year. Preoperative knee range was categorized into "low" (≤ 109), "moderate" (> 109 to ≤ 120), and "high" (> 120°) flexion and "normal" (± -5) and "restricted" (> +5°) terminal extension. Recovery was analyzed using MIXED modeling procedures. The low-flexion group gained flexion across time. The moderate-flexion and high-flexion groups lost flexion initially then recovered, but 1-year flexion remained lower than preoperative values. The restricted terminal extension group gained extension across time. The normal terminal extension group lost extension initially then recovered to preoperative values at 1 year. Recovery in Oxford score was independent of preoperative knee range limitation. Improvement in knee range postoperatively, but not self-reported behavior, is highly dependent on the initial restriction in range.

The outcome of rotating-platform total knee arthroplasty with cement at a minimum of ten years of follow-up

BACKGROUND

Durable, long-term results have been reported for patients managed with first-generation mobile-bearing total knee arthroplasty. Second-generation mobile-bearing total knee arthroplasty has been introduced to enhance instrumentation, to increase flexion, and to improve functional outcome, but, to our knowledge, no long-term results are available.

METHODS

From May 1999 to June 2000, 116 consecutive rotating-platform total knee arthroplasties were performed by the two senior authors in 112 patients with use of the LPS-Flex Mobile cemented prosthesis, which was implanted with a measured resection technique. The patella was resurfaced in every knee. The average age of the patients at the time of surgery was sixty-nine years (range, thirty-seven to eighty-five years), and seventy-seven patients (eighty knees) were women. The predominant diagnosis was osteoarthritis. The clinical and radiographic evaluation was performed with use of the Knee Society rating system. The level of activity and patient-reported functional outcome were evaluated with use of the University of California at Los Angeles (UCLA) score and the Knee injury and Osteoarthritis Outcome Score (KOOS), respectively.

RESULTS

The average duration of follow-up was 10.6 years (range, ten to 11.8 years). Three patients were lost to follow-up, and five patients died of causes unrelated to knee arthroplasty. Two knees were revised, one because of infection and one because of failure of the medial collateral ligament. Kaplan-Meier survivorship analysis showed an implant survival rate of 98.3% at ten years. For the 104 patients (108 knees) who were evaluated at a minimum of ten years, the average Knee Society knee and function scores improved from 34 to 94 points and from 55 to 88 points, respectively, at the time of the latest follow-up. There was no periprosthetic osteolysis and no evidence of implant loosening on follow-up radiographs. The average knee flexion was 117° preoperatively and 128° at the time of the latest follow-up evaluation. At the time of the latest follow-up, the KOOS quality-of-life score was significantly better for patients with >125° of flexion (p = 0.00034).

CONCLUSIONS

This study demonstrated durable clinical and radiographic results at a minimum of ten years after total knee replacement with a second-generation, cemented, rotating-platform, posterior-stabilized total knee prosthesis. According to the functional outcome results obtained in this study, we believe that this design is a valuable option for active patients undergoing total knee arthroplasty.

Greater satisfaction in older patients with a mobile-bearing compared with fixed-bearing total knee arthroplasty

A prospective, randomized, controlled, double-blind trial was performed to compare outcomes between 61 mobile- and 58 fixed-bearing primary TKAs in patients aged 70 years or older. At last follow-up, no difference was found for Knee Society score. The mobile-bearing group had greater knee flexion at 3 and 6 months, but this was similar at 2 years. The patient satisfaction was better in the mobile-bearing group than in fixed-bearing group, with respect to Knee Society functional score, Western Ontario MacMasters University score, Short-Form 12 score, and visual analog scale score. A multivariate analysis confirmed that the only independent factors predictive of postoperative quality of life were early postoperative flexion. We believe that better perception and satisfaction with mobile-bearing in older patients was due to the earlier regain of their knee flexion. Our results justify the use of mobile-bearing design in the older population.

Does greater knee flexion increase patient function and satisfaction after total knee arthroplasty?

The purpose of this study was to determine whether high flexion leads to improved benefits in patient satisfaction, perception, and function after total knee arthroplasty (TKA). Data were collected on 122 primary TKAs. Patients completed a Total Knee Function Questionnaire. Knees were classified as low (≤ 110°), mid (111°-130°), or high flexion (>130°). Correlation between knee flexion and satisfaction was not statistically significant. Increased knee flexion had a significant positive association with achievement of expectations, restoration of a "normal" knee, and functional improvement. In conclusion, although the degree of postoperative knee flexion did not affect patient satisfaction, it did influence fulfillment of expectations, functional ability, and knee perception. This suggests that increased knee flexion, particularly more than 130°, may lead to improved outcomes after TKA.

Patient perception of outcomes following failed spinal instrumentation with polyetheretherketone rods and titanium rods

STUDY DESIGN

A structured questionnaire.

OBJECTIVE

The purpose of this study was to determine whether material rod composition and its imaging characteristics can determine patient perceptions of pain, outcome, and need for revision surgery in the context of the failure of spinal instrumentation following lumbar arthrodesis.

SUMMARY OF BACKGROUND DATA

Patient perceptions of radiographic images in the context of failed spinal instrumentation may influence clinical outcomes and patient satisfaction. Due to radiolucency, failed polyetheretherketone (PEEK) rods may be perceived differently by patients than more traditional materials.

METHODS

Patients presenting primarily with chief complaints of back pain completed a 2-page, 22-question questionnaire containing 3 alternative radiographic images of failed rod instrumentation following posterolateral lumbar arthrodesis. The images represented failed rods composed of either PEEK, PEEK with a longitudinal radio-opaque marker, or traditional titanium. Statistical analysis with the Cochran Q test was performed to determine whether there were statistical differences in the responses.

RESULTS

The responses suggested a preference for the images representing PEEK instrumentation as being associated with superior clinical outcomes, the least pain, the most comfort, and the least likelihood of required revision surgery.

CONCLUSION

PEEK rods possess radiolucent properties that can alter patient perceptions of clinical outcomes when compared with images of other equally unfavorable scenarios. The significance of these patient perceptions must still be demonstrated. However, they may play an important role in clinical outcomes and patient satisfaction.