Does Posterior Cruciate Ligament Retention or Sacrifice in Total Knee Replacement Affect Proprioception? A Systematic Review

Can pain be improved with retention of the posterior cruciate ligament during total knee arthroplasty?

PURPOSE

The purpose of the current study was to determine if differences exist between cruciate-retaining (CR) and posterior-stabilized (PS) implant articulations for total knee arthroplasty (TKA) with regards to early post-operative pain.

METHODS

We retrospectively reviewed patients who underwent primary TKA, with the same TKA implant design, at our institution between January 2018 and July 2021. Patients were stratified based on whether they received a CR or non-constrained PS (PSnC) articulation and propensity score matched in a 1:1 ratio. A sub-analysis matching patient who received a constrained PS implant (PSC) to those undergoing CR TKA and PSnC TKA was also carried out. Opioid dosages were converted to morphine milligram equivalents (MME).

RESULTS

616 patients after CR TKA were matched 1:1 to 616 patients with a PSnC implant. There were no significant differences between demographic variables. There were no statistically significant differences in opioid usage measured by MME on post-operative day (POD) 0 (p = 0.171), POD1 (p = 0.839), POD2 (p = 0.307), or POD3 (p = 0.138); VAS pain scores (p = 0.175); or 90-day readmission rate for pain (p = 0.654). A sub-analysis of CR versus PSC TKA demonstrated no significant differences in opioid usage on POD0 (p = 0.765), POD1 (p = 0.747), POD2 (p = 0.564), POD3 (p = 0.309); VAS pain scores (p = 0.293); and 90-day readmission rate for pain (p > 0.9).

CONCLUSION

Our analysis demonstrated no significant difference in post-operative VAS pain scores and MME usage based on implant. The results suggest that neither the type of articulation or constraint used for primary TKA has a significant impact on immediate post-operative pain and opioid consumption.

LEVEL III EVIDENCE

Retrospective Cohort Study.

No difference in patient-reported outcomes with cruciate-retaining, anterior-stabilized, and posterior-stabilized total knee arthroplasty designs

Aims

This study compared patient-reported outcomes of three total knee arthroplasty (TKA) designs from one manufacturer: one cruciate-retaining (CR) design, and two cruciate-sacrificing designs, anterior-stabilized (AS) and posterior-stabilized (PS).

Methods

Patients scheduled for primary TKA were included in a single-centre, prospective, three-armed, blinded randomized trial (n = 216; 72 per group). After intraoperative confirmation of posterior cruciate ligament (PCL) integrity, patients were randomly allocated to receive a CR, AS, or PS design from the same TKA system. Insertion of an AS or PS design required PCL resection. The primary outcome was the mean score of all five subscales of the Knee injury and Osteoarthritis Outcome Score (KOOS) at two-year follow-up. Secondary outcomes included all KOOS subscales, Oxford Knee Score, EuroQol five-dimension health questionnaire, EuroQol visual analogue scale, range of motion (ROM), and willingness to undergo the operation again. Patient satisfaction was also assessed.

Results

Patients reported similar levels of pain, function, satisfaction, and general health regardless of the prosthetic design they received. Mean maximal flexion (129° (95% confidence interval (CI) 127° to 131°) was greater in the PS group than in the CR (120° (95% CI 121° to 124°)) and AS groups (122° (95% CI 120° to 124°)).

Conclusion

Despite differences in design and constraint, CR, AS, and PS designs from a single TKA system resulted in no differences in patient-reported outcomes at two-year follow-up. PS patients had statistically better ROM, but the clinical significance of this finding is unclear.

The effectiveness of cruciate-retaining versus posterior-stabilized designs on extensor mechanism function and knee function in patients after simultaneous bilateral total knee arthroplasty: A two-year retrospective follow-up study

INTRODUCTION

The importance of the posterior-cruciate ligament in knee functionality is known; however, the effect of preserving the posterior-cruciate ligament in total knee arthroplasty (TKA) on extensor mechanism function and knee function is not clear. We aimed to compare extensor mechanism function and knee function between patients operated with the cruciate-retaining and posterior-stabilized designs for simultaneous bilateral TKA.

HYPOTHESIS

Patients operated with the cruciate-retaining design would produce better outcomes than those operated with the posterior-stabilized design.

MATERIALS AND METHODS

A total of 104 patients were divided into two groups as the cruciate-retaining (n=52) and posterior-stabilized (n=52) groups. The groups were compared for extensor mechanism function (chair-rise test) and knee function (Hospital for Special Surgery [HSS] knee score). The follow-up points were six weeks, three months, six months, one year and two years.

RESULTS

No statistically significant effect on chair-rise performance of the group-by-time interaction (χ2 [5, n=104]=5.32, p=.37) or of group (χ2 [1, n=104]=1.69, p=.19). In the HSS knee score, the group-by-time interaction was statistically significant (F [5.510]=6.24, p<.001). A statistically significant difference of 7.4 points in favor of the posterior-stabilized group was found at six weeks (p=.002). No statistically significant differences were found between the groups at the other follow-up points.

DISCUSSION

The cruciate-retaining and posterior-stabilized designs have similar outcomes with regard to extensor mechanism function and knee function in the long-term period in patients who underwent simultaneous bilateral TKA. In the short-term period, the posterior-stabilized design shows better knee function than the cruciate-retaining design.

LEVEL OF EVIDENCE

III; a retrospective study.

Comparison of physical function, proprioception, muscle strength, postural balance, and walking in older women with and without total knee arthroplasty

The benefit of total knee arthroplasty (TKA) is that it alleviates pain caused by osteoarthritis; however, other postoperative effects on physical function are unclear. This study aimed to investigate the differences in physical function, proprioception, muscle strength, postural balance, and walking in older women with and without TKA. A total of 36 participants were included in this study; the TKA group comprised older women who underwent TKA (n = 18) and the non TKA group comprised older women who did not undergo TKA (n = 18). All the participants were evaluated for physical function, proprioception, muscle strength, postural balance, and walking. The outcome measures were compared between the 2 groups using an independent t test. Correlations were assessed using Pearson correlation coefficients. Participants in the TKA group had significantly reduced physical function, postural balance, and walking ability compared with those in the non TKA group (P < .05). In the TKA group, physical function was statistically correlated with proprioception, postural balance, and walking (P < .05); in particular, it had a strong correlation with proprioception (R > .60). In the non TKA group, postural balance was significantly associated with muscle strength and walking (P < .05). In particular, it was strongly correlated with walking (R > .90). This study demonstrated that older women undergoing TKA need to actively perform interventions to improve physical function, postural balance, and walking compared with older women with osteoarthritis.

Relationship Between Mechanoreceptors in the Posterior Cruciate Ligament and Patient Age or Osteoarthritis Severity

Background

Mechanoreceptors in the posterior cruciate ligament (PCL) can produce proprioception, which is an important reason why patients choose cruciate-retaining total knee arthroplasty (TKA). The number of mechanoreceptors in the PCL of patients with knee osteoarthritis (OA) is unknown.

Purpose

To provide a theoretical basis for estimating the number of mechanoreceptors in the PCL by evaluating the relationship between this number and patient age or OA severity.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

An overall 28 PCLs from patients with knee OA were collected at the time of TKA and grouped according to patient age (group A, 60-69 years [n = 8]; group B, 70-79 years [n = 12]; group C, ≥80 years [n = 8]) and OA based on Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score (group I, ≤80 [n = 8]; group II, 81-120 [n = 10]; group III, >120 [n = 10]). Hematoxylin and eosin and S-100 immunohistochemical staining were performed on the slices near the tibial attachment of the PCL, and the number of mechanoreceptors in each slice was counted. Multifactor analysis of variance was used to evaluate the relationship between the number of mechanoreceptors and patient age or WOMAC score.

Results

The number of mechanoreceptors (mean ± SD) in groups A, B, and C was 24.00 ± 15.19, 30.92 ± 11.41, and 23.38 ± 11.39, respectively, with no significant between-group differences. The number of mechanoreceptors in groups I, II, and III was 43.50 ± 4.99, 25.00 ± 5.27, and 15.20 ± 5.61, with significant differences between groups I and II, groups I and III, and groups II and III (P < .001 for all).

Conclusion

In patients with knee OA, age had no significant effect on mechanoreceptor count, but the number of mechanoreceptors in the PCL decreased significantly with higher (worse) WOMAC score. These findings suggest that in patients of any age with high WOMAC scores, there may be little value as it relates to knee proprioception in performing a PCL-retaining TKA.

Supervised versus unsupervised rehabilitation following total knee arthroplasty: A systematic review and meta-analysis

BACKGROUND

Outcomes after total knee arthroplasty (TKA) are strongly influenced by the adequacy of rehabilitation and the consequent functional recovery. The economic impact of rehabilitation it is not negligible. Inpatient rehabilitation can be 5 to 26 times more expensive than the home-based rehabilitation. This topic is extremely relevant as the COVID-19 pandemic has highlighted the importance of unsupervised rehabilitation in orthopedic surgery. The aim of this review and meta-analysis is to investigate the scientific evidence regarding the comparison between supervised and unsupervised rehabilitation following TKA.

MATERIALS AND METHODS

Following PRISMA guideline, a comprehensive search of PubMed, Cochrane and Scopus databases using combinations of keywords and MeSH descriptors: "total "Knee replacement," "Arthroplasty", "Rehabilitation" was performed from inception to December 2021. All relevant articles were retrieved, and their bibliographies were searched for further relevant references. Only English written randomized controlled trials comparing supervised and unsupervised rehabilitation following TKA were included in this systematic review. The outcomes considered were long-term pain, physical function, knee flexion and extension ROM, 6 minute walking test (6MWT) and timed up and go test (TUG).

RESULTS

11 studies (2.181 patients in total) were included in this systematic review. The long-term pain outcome showed no significant differences (Std. Mean Difference [SMD] = 0.00, 95 % confidence interval [CI] -0.16, 0.017) between the supervised (n = 397) and unsupervised (n = 255). Physical function showed no significant differences among the two groups (mean difference [MD] = 0.84, 95 % CI = -1.82, 3.50). Non-significant differences were also found for knee ROM flexion (mean difference [MD] = -0.46, 95 % CI = -2.95, 2.04) and for knee extension (mean difference [MD] = 0.54, 95 % CI = -0.89, 1.97). At the 52-week follow-up, the unsupervised group showed significant better results in 6MWT (mean difference [MD] = -26.10, 95 % CI = -47.62, -4.59) and in Timed up and go test (mean difference [MD] = 1.33, 95 % CI = 0.50, 2.15).

CONCLUSION

This systematic review did not show a significant clinical difference in improving pain, function, and mobility outcomes after TKA between supervised PT and unsupervised PT. Therefore, it would appear that supervised rehabilitation did not had additional benefits compared to unsupervised rehabilitation.

No Significant Differences in Clinical and Radiographic Outcomes between PCL Retained or Sacrificed Kinematic Aligned Medial Pivot Total Knee Arthroplasty in Varus Knee

In the last decades, several surgical techniques, such as medial pivot (MP) philosophy and kinematic alignment (KA), have been introduced in total knee arthroplasty (TKA) to improve patients’ outcomes. This retrospective study aims to evaluate the clinical, radiographic, and functional results of PCL preservation or sacrifice in KA MP-TKA. A consecutive series of 147 patients older than 60, with a minimum follow-up of two years, were treated with TKA for severe primary knee osteoarthritis (OA) at the Department of Orthopedics and Traumatology between 1 January 2019, and 1 July 2020. After excluding those not meeting the inclusion criteria, 64 patients were included in the study analysis. Regarding radiographic outcomes, no statistically significant difference was observed between patients with preserved or sacrificed PCL (p > 0.05). A slight improvement in Knee Society Score (KSS), knee and function score, and FJS was observed for the PCL-preserved group, although this superiority tendency was not statistically significant (p > 0.05). PCL-preserved MA MP-TKA reported a statistically significant result in only two questions on the FJS questionnaire (p < 0.05). A slight, non-statistically significant improvement in active ROM was found in the PCL-sacrificed group (p > 0.05). No interventions or revisions were reported in this case series for all treated patients at the final follow-up. No significant differences were described in clinical, radiographic, and functional outcomes in preserved or sacrificed PCL KA MP-TKA. Although not significant, a slight trend toward better clinical outcomes was reported in PCL-preserved KA MP-TKA.

A comparison of balance and fall risk in patients with unilateral and bilateral total knee arthroplasty

BACKGROUND

Static or dynamic postural control cannot be fully restored in patients with knee osteoarthritis, even after total knee arthroplasty (TKA), which may contribute to an increased risk of falls in the elderly.

OBJECTIVE

To evaluate balance and the fall risk before and after TKA in patients with bilateral knee osteoarthritis. Secondary outcomes were patient-reported and performance-based activity limitations.

METHODS

A total of 45 patients were separated into two groups as unilateral TKA (UTKA, n= 24) and bilateral TKA (BTKA, n= 21) groups. All the patients received standard postoperative physical therapy for 3 months. Balance and fall risk (Biodex Balance System SD), patient-reported and performance-based functionality (WOMAC, 30-second chair-stand test, 9-step stair climbing test and 40-meter fast-paced walk test) and Short Form-12 (SF-12) were evaluated at preoperatively, and at 3 months postoperatively.

RESULTS

There was no difference between the groups in postoperative fall risk and balance (p> 0.05). The BTKA group obtained better results in the sit-to-stand test and SF-12 physical dimension (p< 0.05).

CONCLUSIONS

UTKA and BTKA interventions and the standard postoperative rehabilitation were seen to improve balance and quality of life, and reduce the fall risk, patient-reported and performance-based activity limitations. However, despite improvements in balance, the risk of falling persists.

Anterior and Posterior Cruciate Ligaments Mechanoreceptors: A Review of Basic Science

Proprioception is a specialized sensory modality encompassing the movement of the joint and its position in space, and it involves the conversion of mechanical deformation of tissues into neural signals. Mechanoreceptors are specialized nerve structures able to transmit mechanical deformation through electrical signals to dorsal root ganglion sensory neurons and are abundant in the muscles, tendons and ligaments of the knee joint. They are believed to play an important role in knee proprioception and dynamic knee stability. Proprioception should always be taken into consideration for successful reconstruction of the cruciate-deficient knee and for pain and function management in the arthritic knee. Advances in histological methods of detection are numerous and continue to highlight the presence and role of mechanoreceptors after ligament reconstruction, depending on choice of graft. In this review, we present the current knowledge of anterior and posterior cruciate ligaments and grafts mechanoreceptors, and their role in proprioception of knee joint, focusing on each type of mechanoreceptors.