PERSONALISED KNEE REPLACEMENT
What is the current status of conventional knee replacement surgery?
Total knee replacements are one of the commonly done orthopaedic procedures. Studies have shown that the have excellent long-term survivorship. However, multiple studies have shown that about 20% of the patients still are not happy with their knee replacements (i.e., 1 in 5 patients). The functional outcome and patient satisfaction following knee replacements are not as good as hip replacements. This has not changed significantly despite various improvements in implant designs and techniques like computer assisted surgery. While there are multiple reasons for less satisfactory outcome, it is being increasingly recognised that one of the problems may be that the gold standard neutral mechanical alignment technique (even if done accurately) may not be the correct target for several patients.
While aiming for the same alignment target for every patient may make the surgical procedures reproducible within the margin of human error, it probably means that even if the correct universal target of mechanical alignment is achieved perfectly during surgery, it may not be the correct target for that patient resulting in poor outcome despite good looking x-rays. If the alignment target is personalised, the knee replacement may feel more natural and potentially may result in better functional outcome. Essentially, the aim of personalised alignment knee replacement is to recreate the knee joint to pre-arthritic anatomy is the hope that we could reduce the proportion of dissatisfied patients. There are recent reports indication that functional outcome following personalised alignment technique may be better than conventional technique.
Mr. Ganapathi has been using the Personalised alignment concept for doing knee replacements since 2020 (using 3D mould technique initially and now using Robotic Assistance). In his personal experience the requirement for soft tissue release has decreased and patients seem to recover faster.
Personalised Alignment & 3D moulds
Personalised Alignment Concept
References:
1.Patient-reported outcomes after total hip and knee arthroplasty: comparison of midterm results
J Arthroplasty. 2009 Feb;24(2):210-6.
Vikki Wylde 1, Ashley W Blom, Sarah L Whitehouse, Adrian H Taylor, Giles T Pattison, Gordon C Bannister
Abstract: The aim of this study was to compare the midterm functional outcomes of total knee arthroplasty (TKA) and total hip arthroplasty (THA). A cross-sectional postal audit survey of all consecutive patients who had a primary joint replacement at one orthopedic center 5 to 8 years ago was conducted. Participants completed an Oxford hip score or Oxford knee score, which are self-report measures of functional ability. Completed questionnaires were returned from 1112 THA patients and 613 TKA patients, giving a response rate of 72%. The median Oxford knee score of 26 was significantly worse than the median Oxford hip score of 19 (P < .001). In conclusion, TKA patients experience a significantly poorer functional outcome than THA patients 5 to 8 years postoperatively.
2.Comparison of hip and knee arthroplasty outcomes at early and intermediate follow-up
Orthopedics. 2009 Mar;32(3):168.
Seamus O’Brien 1, Damien Bennett, Emer Doran, David E Beverland
Abstract: A common perception among clinicians and patients is that recovery is similar following total hip arthroplasty (THA) and total knee arthroplasty (TKA). Improvement in the outcomes of 337 THAs and 256 TKAs implanted by the same surgeon between April 2003 and November 2005 were compared. Improvement was measured using changes in Oxford hip and knee scores measured preoperatively, at first follow-up, and 1 year postoperatively for each patient. Improvements between preoperative review and first follow-up and between preoperative review and 1-year postoperative follow-up were significantly greater for THA compared to TKA patients. Improvements between first postoperative follow-up and 1-year postoperative follow-up were not significantly different between THA and TKA patients. Although THA patients displayed a significantly worse score preoperatively, they displayed a significantly better score at both first follow-up and 1-year postoperative follow-up. While both procedures improve postoperative pain and physical function, as measured by the Oxford score, improvements measured relative to preoperative levels were significantly smaller for TKA compared to THA patients. Despite recent advances in knee arthroplasty surgery, a significant proportion of TKA patients achieve relatively poor outcome scores postoperatively. This study shows that pain and function improve less and more slowly in the early and intermediate postoperative periods for knee compared to hip arthroplasty patients.
3.Patient satisfaction following total knee arthroplasty using restricted kinematic alignment
Bone Joint J. 2021 Jun;103-B (6 Supple A):59-66.
Sarag Abhari 1, Thomas M Hsing 1 2, Max M Malkani 3, Austin F Smith 1, Langan S Smith 4, Michael A Mont 5, Arthur L Malkani 1
Abstract
Aims: Alternative alignment concepts, including kinematic and restricted kinematic, have been introduced to help improve clinical outcomes following total knee arthroplasty (TKA). The purpose of this study was to evaluate the clinical results, along with patient satisfaction, following TKA using the concept of restricted kinematic alignment.
Methods: A total of 121 consecutive TKAs performed between 11 February 2018 to 11 June 2019 with preoperative varus deformity were reviewed at minimum one-year follow-up. Three knees were excluded due to severe preoperative varus deformity greater than 15°, and a further three due to requiring revision surgery, leaving 109 patients and 115 knees to undergo primary TKA using the concept of restricted kinematic alignment with advanced technology. Patients were stratified into three groups based on the preoperative limb varus deformity: Group A with 1° to 5° varus (43 knees); Group B between 6° and 10° varus (56 knees); and Group C with varus greater than 10° (16 knees). This study group was compared with a matched cohort of 115 TKAs and 115 patients using a neutral mechanical alignment target with manual instruments performed from 24 October 2016 to 14 January 2019.
Results: Mean overall patient satisfaction for the entire cohort was 4.7 (SE 0.1) on a 5-point Likert scale, with 93% being either very satisfied or satisfied compared with a Likert of 4.3 and patient satisfaction of 81% in the mechanical alignment group (p < 0.001 and p < 0.006 respectively). At mean follow-up of 17 months (11 to 27), the mean overall Likert, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, Western Ontario and McMaster Universities Osteoarthritis Index, Forgotten Joint Score, and Knee Society Knee and Function Scores were significantly better in the kinematic group than in the neutral mechanical alignment group. The most common complication in both groups was contracture requiring manipulation under anaesthesia, involving seven knees (6.1%) in the kinematic group and nine knees (7.8%) in the mechanical alignment group.
Conclusion: With the advent of advanced technology, and the ability to obtain accurate bone cuts, the target limb alignment, and soft-tissue balance within millimetres, using a restricted kinematic alignment concept demonstrated excellent patient satisfaction following primary TKA. Longer-term analysis is required as to the durability of this method.
Meta-Analysis
4.Kinematic alignment versus mechanical alignment in primary total knee arthroplasty: an updated meta-analysis of randomized controlled trials
J Orthop Surg Res. 2022 Apr 4;17(1):201.
Binfeng Liu 1 2 3, Chengyao Feng 1 3, Chao Tu 4 5
Abstract
Background: The purpose of this study was to perform an updated meta-analysis to compare the outcomes of kinematic alignment (KA) and mechanical alignment (MA) in patients undergoing total knee arthroplasty.
Methods: PubMed, EMBASE, Web of Science, Google Scholar, and the Cochrane Library were systematically searched. Eligible randomized controlled trials regarding the clinical outcomes of patients undergoing total knee arthroplasty with KA and MA were included for the analysis.
Results: A total of 1112 participants were included in this study, including 559 participants with KA and 553 patients with MA. This study revealed that the Western Ontario and McMaster Universities Osteoarthritis Index, Knee Society Score (knee and combined), and knee flexion range were better in the patients with kinematic alignment than in the mechanical alignment. In terms of radiological results, the femoral knee angle, mechanical medial proximal tibial angle, and joint line orientation angle were significantly different between the two techniques. Perioperatively, the walk distance before discharge was longer in the KA group than in the MA group. In contrast, other functional outcomes, radiological results, perioperative outcomes, and postoperative complication rates were similar in both the kinematic and mechanical alignment groups.
Conclusions: The KA technique achieved better functional outcomes than the mechanical technique in terms of KSS (knee and combined), WOMAC scores, and knee flexion range.