The medial gap is a reliable indicator for intraoperative soft tissue balancing in posterior-stabilized total knee arthroplasty

Seito, Naoki; Suzuki, Kôji; Mikami, Sadayoshi; Uchida, Jun; Hara, Noriyuki

doi:10.1016/j.knee.2021.01.013

Cited by 6 publications

(2 citation statements)

References 38 publications

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“…Since the accuracy of the bone cut is increasing owing to the development of the navigation and robot systems [15], such inter‐surgeon difference may have significant clinical relevance in robotic‐assisted TKAs. Because the medial flexion gap is a reliable indicator of soft‐tissue balancing and is associated with patient satisfaction and patient‐reported subjective scores after TKA [1, 16, 19], manual stress measurements in navigation and robot systems must be improved [4, 21, 22].…”

Section: Discussionmentioning

confidence: 99%

Joint gap produced by manual stress is dependent on the surgeon’s experience and is smaller in flexion in robotic-assisted total knee arthroplasty

Sohmiya

Matsumoto

Nakamura

et al. 2022

Knee Surg Sports Traumatol Arthrosc

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PurposeThis study aimed to retrospectively investigate (1) the reproducibility of gap measurements by manual stress using the Z‐shaped retractor depending on the surgeon’s experience with this maneuver and (2) the consistency of the gap distraction force produced by manual stress throughout the range of motion (ROM) in the robotic‐assisted total knee arthroplasty (TKA). It was hypothesized that the joint gap produced by manual stress is not reproducible depending on the surgeon’s experience, and the distraction force applied by manual stress throughout the ROM is not constant. MethodsMedial and lateral joint gaps were obtained throughout the ROM by manual stress or a tensioner by two surgeons with different levels of experience in robotic‐assisted TKA. The association between the differences in gap measurement by the two surgeons and the preoperative radiographic parameters, including the hip‐knee‐ankle (HKA) angle and absolute and relative varus/valgus laxities were analyzed. ResultsThe experienced surgeon produced significantly greater gaps than the inexperienced surgeon from 0° to 100° flexion, with a mean difference of 0.35 ± 0.12 mm in the medial gap (p < 0.0001), and from 10° to 120° flexion with a mean difference of 0.57 ± 0.13 mm in the lateral gap (p < 0.0001). The tensioner produced a significantly greater medial gap from 70° to 110° flexion with a mean difference of 0.32 ± 0.01 mm in the medial gap (p < 0.0001) and from 0° to 110° flexion with a mean difference of 1.12 ± 0.26 mm in the lateral gap (p < 0.0001). The differences in gap distance by manual stress between experienced and inexperienced surgeons were moderately correlated with the HKA angle in the lateral gap (r = 0.40, p = 0.01). The gap differences due to manual stress and a tensioner showed moderate negative correlation with the HKA angle in the medial gap (r = − 0.50, p = 0.001) and weak negative correlation with the absolute valgus laxity in the lateral gap (r = − 0.35, p = 0.03). ConclusionsThe joint distraction force by manual stress may differ depending on the surgeon’s experience and tended to be smaller in deep flexion; therefore, the flexion gap may be underestimated. Surgeons should determine implant positioning considering gap balance by manual stress, taking into account these characteristics of the manual stress maneuver. Level of evidenceLevel III, retrospective cohort study.

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Section: Discussionmentioning

confidence: 99%

Joint gap produced by manual stress is dependent on the surgeon’s experience and is smaller in flexion in robotic-assisted total knee arthroplasty

Sohmiya

Matsumoto

Nakamura

et al. 2022

Knee Surg Sports Traumatol Arthrosc

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“…However, these tools do not account for the magnitude of forces applied by the surgeon during gap assessment; thus, interpretation of these outputs may be confounded by variations in applied load. Tensor devices that distract the knee in extension and flexion have the advantage of controlling the distraction force [23,31]. However, these devices do not replicate how surgeons examine the knee intraoperatively [23,35].…”

Section: Introductionmentioning

confidence: 99%

Arthroplasty Surgeons Differ in Their Intraoperative Soft Tissue Assessments: A Study in Human Cadavers to Quantify Surgical Decision-making in TKA

Elmasry

Sculco

Kahlenberg

et al. 2022

Clin Orthop Relat Res

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Background In TKA, soft tissue balancing is assessed through manual intraoperative trialing. This assessment is a physical examination via manually applied forces at the ankle, generating varus and valgus moments at the knee while the surgeon visualizes the lateral and medial gaps at the joint line. Based on this examination, important surgical decisions are made that influence knee stability, such as

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Intraoperative lateral laxity greater than 4° is associated with inferior functional improvement in posterior‐stabilised total knee arthroplasty

Inokuchi,

Muratsu,

Kamenaga

et al. 2024

Knee surg. sports traumatol. arthrosc.

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PurposeThe study aimed to determine the impact of intraoperative lateral laxity at extension on clinical and functional outcomes 1 year after posterior‐stabilised total knee arthroplasty (PS‐TKA).MethodsIn total, 91 varus‐type osteoarthritic knees that underwent PS‐TKA using the medial preservation gap technique were included. After the femoral trial component placement and patellofemoral joint reduction, the soft‐tissue balance was assessed using an offset‐type tensor with a 40‐lb joint‐distraction force. Patients were divided into the following three groups according to the intraoperative lateral laxity at extension (i.e., varus ligament balance) using the mean ± 1 standard deviation: Groups A, ≤0°; B, 0–4°; and C, >4°. The 2011 Knee Society Score (KSS) and 3‐m timed up‐and‐go test (TUG) time 1‐year postoperatively, and their improvements were compared among the groups.ResultsWhile significant improvements were observed in all subscales of the 2011 KSS and TUG post‐TKA (p < 0.05), the improvement of functional activities and TUG time were significantly lower in Group C than in Group B (p < 0.05). However, no significant differences were observed in symptom improvement, patient satisfaction or patient expectation scores among the groups.ConclusionAn excessive lateral laxity (varus angle) >4° at extension was associated with lower improvement in functional ability 1‐year postoperatively. Therefore, excessive intraoperative lateral laxity should be avoided in PS‐TKA.Level of EvidenceLevel IV.

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The medial gap is a reliable indicator for intraoperative soft tissue balancing in posterior-stabilized total knee arthroplasty

Cited by 6 publications

References 38 publications

Joint gap produced by manual stress is dependent on the surgeon’s experience and is smaller in flexion in robotic-assisted total knee arthroplasty

Joint gap produced by manual stress is dependent on the surgeon’s experience and is smaller in flexion in robotic-assisted total knee arthroplasty

Arthroplasty Surgeons Differ in Their Intraoperative Soft Tissue Assessments: A Study in Human Cadavers to Quantify Surgical Decision-making in TKA

Intraoperative lateral laxity greater than 4° is associated with inferior functional improvement in posterior‐stabilised total knee arthroplasty

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