The Disproportionate Increase of the Intraoperative Flexion and Extension Gap Space after Posterior Cruciate Ligament Resection in Total Knee Arthroplasty

Purpose: Maintaining gap balance is critical for total knee arthroplasty (TKA). This study aimed to elucidate if the extension–flexion gaps would be changed with posterior cruciate ligament (PCL) intact (PI) and PCL resection (PR) during TKA. The flexion gaps were measured using two methods, open-(Fo) and closed-chain position (Fc), based on the definition of kinetic chain position, respectively. Methods: This retrospective study enrolled a total of 33 patients who underwent posterior-stabilized (PS) TKA for symptomatic advanced osteoarthritis of knees. After bone cuts were completed, the extension–flexion gaps before and after PCL resection during TKA were measured using a calibrated tensioning device set at a 100 Nm distraction force. To further differentiate the effect of thigh weight on the 90° flexion gap, two varied methods of examination, either in closed chain (Fc) or open chain (Fo) were performed. Results: The increases in the 90° knee flexion gap after PCL resection were measured by both methods, i.e., ΔFc (PR-Fc—PI-Fc): 2.04 ± 2.06 mm, p < 0.001; and mean ΔFo (PR-Fo—PI-Fo): 1.64 ± 1.36 mm, p < 0.001. However, there were no differences between ΔFc and ΔFo before and after PCL resection. A greater amount of flexion gap was identified in open chain than in closed chain after PCL resection, and the PR-Fo and PR-Fc were 14.36 ± 3.13 and 11.40 ± 3.47 (p < 0.001), respectively. Conclusions: The resection of PCL during TKA distinctly increased the flexion gap, but not the extension gap. This disproportionate increase of the gap will cause a gap balance mismatch. The tensioning maneuver in open-chain was more effective to detect the gap differences than in closed-chain before and after PCL resection during TKA.

A STUDY TO COMPARE FIXED BEARING AND MOBILE BEARING TOTAL KNEE ARTHROPLASTY IN TERTIARY MEDICAL CENTRE, MUMBAI

Intro- For TKA, there are two types of bearing designs: xed-bearing and mobile-bearing. Round femoral components articulate with a relatively at tibial articular surface in a xed-bearing knee design. Because the insert does not hinder the natural movements of the femoral component, the mobile-bearing (MB) TKA design is thought to allow more exibility of motion than the xed-bearing (FB) variety. Aim and objective: To compare xed bearing and mobile bearing total knee arthroplasty. Material and methods:This study is a prospective type of study done at Seth GS medical college Mumbai, Department of Orthopaedics during August 2019 to June 2021 on patients undergoing total knee arthroplasty. Patients who were to undergo total knee arthroplasty were invited to take part in the study. This study, done on them was explained in detail to them. An informed consent was obtained. Patients fullling the inclusion criteria were listed. Result: Range of motion achieved after mobile arthroplasty was 123.62±2.94 and in xed arthroplasty it was 121.96±2.74. Pain after last follow up in mobile arthroplasty was 48.83±0.62 and for xed arthroplasty was 47.39±0.86. Flexion gap after last follow up in mobile arthroplasty was 24.13±0.45 and in xed was 24.02±0.45. Stability was almost similar in both mobile and xed arthroplasty. Conclusions: there is no signicant difference between xed arthroplasty and mobile arthroplasty as far as Range of motion, Pain ,Flexion gap. Stability was almost similar in both mobile and xed arthroplasty.

The Impact of Intraoperative Gap Difference Between Extension and Flexion on Perception of Joint Function After Total Knee Arthroplasty: a Comparative Retrospective Study

Background: The argument presupposes that intra-operative soft tissue balance is associated with patient-reported outcome measures after total knee arthroplasty (TKA). Our aim was to assess the association between the extension-to-flexion gap and patients’ reported perception of knee joint function.Methods: This was a retrospective study of 60 cases of primary cruciate-retaining TKAs performed for the treatment of medial-compartment knee osteoarthritis, at a mean follow-up of 2.6 (range, 2.0–5.2) years. Knee perception was evaluated by asking patients whether they considered their knee joint as “natural” (grade I) or “artificial”, with or without restrictions (grades II–V). The following factors were compared between the two groups: age, sex, and the extension-to-flexion gap difference. A multiple logistic regression analysis was used to identify predictive factors of an artificial knee joint perception. A receiver operating characteristic curve analysis was used to identify cut-off values of predictive factors. Result: Compared to a natural knee joint perception (26 knees, 43%), an artificial perception (34 knees, 57%) was associated with a smaller gap difference at the distraction force of 20 lbf (p < .001), 30 lbf (p = .022), and 40 lbf (p = .038), a lower EuroQol 5-Dimension score (p = .029), and self-reported joint health (Knee injury and Osteoarthritis Outcome Score-Joint Replacement [KOOS-JR], p = .032). A gap difference <1.0 mm was a predictive of an artificial perception (odds ratio, 1.63; 95% confidence interval, 1.33–4.54; p < .001). A cut-off gap difference of 0.99 mm at 20 lbf predicted an artificial perception with a sensitivity of 81.5% and a specificity of 87.9%. Post-operative satisfaction (p < .001), KOOS-JR (p < .001), patient’s joint perception (p = .006), pain (p = .015), and EuroQol 5-Dimension (p = .032) differed between the two groups when the gap difference threshold was set to 1.0 mm.Conclusion: Careful balancing of soft tissue during TKA to achieve an extension-to-flexion gap ≥ 1.0 mm can improve patients’ perception of knee joint function and quality of life.

The Influence of the Posterior Slope Angle and Posterior Condylar Offset in Posterior-Stabilized Total Knee Arthroplasty Was Analyzed From the Way of Constructing Flexion Gap

IntroductionThe purpose of this study was to compare the effects of two ways of establishing the flexion gap on the flexion angle and flexion-extension motion after posterior-stabilized （PS） prosthesis. A way for the posterior slope angle（PSA）and posterior condylar offset（PCO）were greater than preoperative, another for less than preoperative.Materials and MethodsThey are grouped according to the way flexion gaps are constructed. Data from 28 total knee arthroplasty（TKA）patients treated with propensity score match (PSM) were included. The difference of flexion angle and flexion-extension motion between the two groups was compared, and the influence of PCO and PSA on the flexion angle in the two ways was analyzed.ResultsPostoperative flexion degree of the two groups was 115.50±14.64° and 112.29±10.64° (P =0.553), and there was no statistical significance. Postoperative flexion-extension motion grade data of the decrease group was better than that of the increased group (P =0.031). Postoperative flexion angle was negatively correlated with PCO change in the increase group (r²=0.574 b '=-0.758 p=0.002).ConclusionsIncreasing the PSA and PCO to construct flexion gaps in PS TKA will cause problems with flexion-extension movements. It may be more reasonable to avoid excessive PSA and select appropriate PCO to reconstruct the flexion gap in PS prosthetic.

Accuracy of total knee arthroplasty using the modified gap technique based on the bone gap: an evaluation of the bone gap with a distal femoral trial component

Background In total knee arthroplasty (TKA) using the modified gap technique, the soft-tissue balance is measured after osteotomy of the distal femur and proximal tibia (conventional bone gap). However, after osteotomy, the flexion gap size during 90° knee flexion may be larger than that observed after implantation. The tension of the lateral compartment during 90° flexion may also be reduced after osteotomy of the distal femur. We manufactured a distal femoral trial component to reproduce the condition after implantation and prior to posterior condyle osteotomy. This study aimed to evaluate the effect of the trial component on the flexion gap. Methods This prospective study included 21 consecutive patients aged 78 years with medial osteoarthritis who underwent cruciate-retaining TKA between February 2017 and March 2018. The postoperative flexion gap size and inclination during 90° flexion were compared between cases with and without the trial component. Results The mean joint gap size with the trial component (13.4 ± 0.80 mm) was significantly smaller than that without the trial component (14.7 ± 0.84 mm). The mean gap inclination angle with the trial component (3.7° ± 0.62°) was significantly smaller than that without the trial component (5.5° ± 0.78°). Conclusions In the present study, the joint gap size and medial tension were significantly reduced after the trial component had been set. Accurate measurement of the soft-tissue balance is an important factor in the modified gap technique, and this method using a distal femoral trial component can offer better outcomes than those achieved with conventional methods.

Short- to mid-term outcomes of computer navigation assisted total knee arthroplasty using adjusted mechanical alignment compared to mechanical alignment

Purpose To evaluate efficacy of navigation-assisted total knee arthroplasty (TKA) achieved using adjusted mechanical alignment (aMA) and mechanical alignment (MA) technique. Methods The authors performed a retrospective study enrolled a single-center series of patients who underwent navigation-assisted TKA with aMA (n = 77) and with MA (n = 61) technique. The demographic data was recorded. Functional scores including Hospital for Special Surgery score, Western Ontario and McMaster Universities Osteoarthritis Index score and Forgotten Joint Score-12 were evaluated. In addition, the parameter of resection and soft tissue balance as well as radiographic evaluation was measured and compared between groups. Results The HSS score at 1-month and 6-months postoperatively were significant higher using aMA compared to MA. The postoperative coronal alignment was made with a mean of 1.11° more varus/valgus in the aMA group compared to MA. The femoral prosthesis was positioned in a mean of 2.29° more varus/valgus using aMA compared to MA. The medial extension gap was significantly tighter in the MA group. In addition, the femoral prosthesis in the aMA group was positioned in a mean of 0.77° more external rotation than the MA group. The lateral flexion gap was wider in the aMA group with a mean of 0.71 mm more laxity. Conclusions Both aMA and MA technique in TKA obtained good clinical outcomes. Notably, aMA-TKA grant superior functional scores at 1-month and 6-months follow-up, might due to the preservation of mild constitutional frontal deformity with less release of soft tissue and a biomimetic wider lateral flexion gap was remained.