Abstract
Purpose
It has not been established whether changes in the length of the patellar tendon (LPT) after total knee arthroplasty (TKA) affect clinical outcomes. Therefore, this prospective cohort study aimed to evaluate changes in the LPT over time postoperatively and clarify their impact on clinical outcomes after bilateral TKA, performed with differently designed mobile-bearing (meniscal-bearing and rotating-platform) implants on contralateral knees.
Methods
51 patients who required staged bilateral mobile-bearing TKA were recruited. LPT was evaluated by measuring the Insall–Salvati ratio (ISR) preoperatively and at 1 week, 6 months, and 1, 2, and ≥ 5 years postoperatively. Hospital for Special Surgery score and range of motion were assessed at the final follow-up.
Results
Based on the ISR, there were no differences in the patterns of change between the two types of implant (n.s.). At the 6-month follow-up, the ISRs of both implants had significantly decreased (p = 0.002). Throughout the follow-up, the ISR was significantly lower (p < 0.001) for the meniscal-bearing knees than for the rotating-platform knees. After the 1-year follow-up, there were no further substantial changes in the ISR in either group. There was also no significant correlation between the ISR and clinical outcomes.
Conclusions
LPT decreased after both mobile-bearing TKAs for up to 1 year postoperatively, although the decrease was more significant for the meniscal-bearing knees than the rotating-platform knees. After 1 year postoperatively, however, these conditions had stabilized, with no further changes. Thus, LPT plays a minimal role in mid-to-long-term clinical outcomes after TKA.
Level of evidence
Therapeutic prospective study, Level II.
Similar content being viewed by others
References
Alicea J (2001) Scoring systems and their validation for the arthritic knee. In: Insall JN, Scott WN (eds) Surgery of the knee, vol 2, 3rd edn. Churchill Livingstone, New York, pp 1507–1515
Behrend H, Graulich T, Gerlach R, Spross C, Ladurner A (2018) Blackburne-Peel ratio predicts patients’ outcomes after total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc. https://doi.org/10.1007/s00167-018-5016-1
Brilhault J, Ries MD (2010) Measuring patellar height using the lateral active flexion radiograph: effect of total knee implant design. Knee 17:148–151
Buechel FF (1994) Meniscal bearing knee replacement: development, long-term results, and future technology. In: Scott WN (ed) The knee, vol 2. Mosby-Year Book, St. Louis, pp 1157–1177
Cabral F, Sousa-Pinto B, Pinto R, Torres J (2017) Patellar height after total knee arthroplasty: comparison of 3 methods. J Arthroplasty 32:552–557
Chougule SS, Stefanakis G, Stefan SC, Rudra S, Tselentakis G (2015) Effects of fat pad excision on length of the patellar tendon after total knee replacement. J Orthop 12:197–204
Davies GS, van Duren B, Shorthose M, Garfjeld Roberts P, Morley JR, Monk AP, Murray DW, Pandit HG (2016) Changes in patella tendon length over 5 years after different types of knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 24:3029–3035
Dennis DA, Kim RH, Johnson DR, Springer BD, Fehring TK, Sharma A (2011) Control-matched evaluation of painful patellar crepitus after total knee arthroplasty. Clin Orthop Relat Res 469:10–17
Ewald FC (1989) The Knee Society total knee arthroplasty roentgenographic evaluation and scoring system. Clin Orthop Relat Res 248:9–12
Flören M, Davis J, Peterson MGE, Laskin RS (2007) A mini-midvastus capsular approach with patellar displacement decrease the prevalence of patellar baja. J Arthroplasty 22(6 suppl 2):51–57
Insall JS, Salvati E (1971) Patella position in the normal knee joint. Radiology 101:101–104
Ishii Y, Noguchi H, Sato J, Yamamoto T, Takayama S, Toyabe SI (2017) Comparison of long-term clinical outcomes after bilateral mobile-bearing total knee arthroplasties using PCL-retaining and PCL-substituting implants in the same patients. Knee Surg Sports Traumatol Arthrosc 25:3711–3717
Ishii Y, Noguchi H, Takeda M, Sato J, Toyabe S (2011) Prediction of range of motion two years after mobile-bearing total knee arthroplasty—effect of retention of the posterior cruciate ligament. Knee Surg Sports Traumatol Arthrosc 19:2002–2008
Jawhar A, Sohoni S, Shah V, Scharf HP (2014) Alteration of the patellar height following total knee arthroplasty. Arch Orthop Trauma Surg 134:91–97
Koshino T, Ejima M, Okamoto R, Morii T (1990) Gradual low riding of the patella during postoperative course after total knee arthroplasty in osteoarthritis and rheumatoid arthritis. J Arthroplasty 5:323–327
Lemon M, Packham I, Narang K, Craig DM (2007) Patellar tendon length after knee arthroplasty with and without preservation of the infrapatellar fat pad. J Arthroplasty 22:574–580
Lewandowski PJ, Askew MJ, Lin DF, Hurst FW, Melby A (1997) Kinematics of posterior cruciate ligament-retaining and -sacrificing mobile bearing total knee arthroplasties. An in vitro comparison of the New Jersey LCS meniscal bearing and rotating platform prostheses. J Arthroplasty 12:777–784
Li Z, Cheng W, Sun L, Yao Y, Cao Q, Ye S, Qi L, Xu S, Wu X, Jing J (2018) Mini-subvastus versus medial parapatellar approach for total knee arthroplasty: a prospective randomized controlled study. Int Orthop 42:543–549
Meneghini RM, Ritter MA, Pierson JL, Meding JB, Berend ME, Faris PM (2006) The effect of the Insall–Salvati ratio on outcome after total knee arthroplasty. J Arthroplasty 21(6 Suppl 2):116–120
Mikashima Y, Ishii Y, Takeda M, Noguchi H, Momohara S, Banks SA (2013) Do mobile-bearing knee arthroplasty motions change with activity? Knee 20:422–425
Morberg P, Chapman-Sheath P, Morris P, Cain S, Walsh WR (2002) The function of the posterior cruciate ligament in an anteroposterior-gliding rotating platform total knee arthroplasty. J Arthroplasty 17:484–489
Pinsornsak P, Naratrikun K, Chumchuen S (2014) The effect of infrapatellar fat pad excision on complications after minimally invasive TKA: a randomized controlled trial. Clin Orthop Relat Res 472:695–701
Pritchett JW (2011) Patients prefer a bicruciate-retaining or the medial pivot total knee prosthesis. J Arthroplasty 26:224–228
Reid MJ, Booth G, Khan RJ, Janes G (2014) Patellar eversion during total knee replacement: a prospective, randomized trial. J Bone Jt Surg Am 96:207–213
Seah RB, Pang HN, Lo NN, Chong HC, Chin PL, Chia SL, Yeo SJ (2012) Evaluation of the relationship between anteroposterior translation of a posterior cruciate ligament-retaining total knee replacement and functional outcome. J Bone Jt Surg Br 94:1362–1365
Seon JK, Park SJ, Yoon TR, Lee KB, Moon ES, Song EK (2010) The effect of anteroposterior laxity on the range of movement and knee function following a cruciate-retaining total knee replacement. J Bone Jt Surg Br 92:1090–1095
Sharma V, Tsailas PG, Maheshwari AV, Ranawat AS, Ranawat CS (2008) Does patellar eversion in total knee arthroplasty cause patella baja? Clin Orthop Relat Res 466:2763–2768
Stiehl JB, Dennis DA, Komistek RD, Keblish PA (2000) In vivo kinematic comparison of posterior cruciate ligament retention or sacrifice with a mobile bearing total knee arthroplasty. Am J Knee Surg 13:13–18
van Houten AH, Heesterbeek PJ, Wymenga AB (2016) Patella position is not a determinant for anterior knee pain 10 years after balanced gap total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 24:2656–2662
Weale AE, Murray DW, Newman JH, Ackroyd CE (1999) The length of the patellar tendon after unicompartmental and total knee replacement. J Bone Jt Surg Br 81:790–795
Acknowledgements
We thank Nancy Schatken, BS, MT (ASCP), from Edanz Group (http://www.edanzediting.com/ac), for editing a draft of this manuscript.
Funding
No external funding was used.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
All authors declare that they have no conflicts of interest.
Ethical approval
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Informed consent
Informed consent was obtained from all individual participants included in the study.
Rights and permissions
About this article
Cite this article
Ishii, Y., Noguchi, H., Sato, J. et al. Insall–Salvati ratio stabilizes one year after mobile-bearing total knee arthroplasty and does not correlate with mid-to-long-term clinical outcomes. Knee Surg Sports Traumatol Arthrosc 27, 1604–1610 (2019). https://doi.org/10.1007/s00167-018-5211-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00167-018-5211-0