Muscle torque in total knee arthroplasty: comparison of subvastus and midvastus approaches


The subvastus and midvastus approaches are two of the most commonly performed quadriceps preserving approaches for total knee arthroplasty (TKA), which can hasten functional recovery and rehabilitation. However, there has not been sufficient investigation with respect to a quantitative comparison between the two approaches in terms of muscle strength. To compare outcomes with respect to muscle strength between these two approaches, quadriceps and hamstring muscle torques of 20 patients who underwent primary TKA with the subvastus (SV) approach and 10 patients who received the midvastus (MV) approach were measured after surgery. The median age of patients in the SV group (68 years, range 53–77 years) was significantly different that the median age of patients in the MV group (61 years, range 50–73 years) (P = 0.0141). There was no significant difference in patient weight, height, or postoperative duration before muscle testing between the SV and MV groups. There were no significant differences in peak muscle torque or hamstring/quadriceps (H/Q) ratio between the groups. We thus conclude peak muscle torque and H/Q ratios were not statistically different with the SV or MV approach, therefore functional outcome is comparable.

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  1. 1.

    Berth A, Urbach D, Neumann W, Awiszus F (2007) Strength and voluntary activation of quadriceps femoris muscle in total knee arthroplasty with midvastus and subvastus approach. J Arthroplasty 22:83–88

    Article  PubMed  Google Scholar 

  2. 2.

    Boyd AD Jr, Ewald FC, Thomas WH, Poss R, Sledge CB (1993) Long-term complications after total knee arthroplasty with or without resurfacing of the patella. J Bone Joint Surg Am 75:674–681

    PubMed  Google Scholar 

  3. 3.

    Callaghan M, Babu V, Ellis D, Samarji R (2009) Electromyographic comparison of the mid-vastus and sub-vastus approaches to total knee arthroplasty. Curr Orthop Pract 20:442–447

    Article  Google Scholar 

  4. 4.

    Chang CH, Chen KH, Yang RS, Liu TK (2002) Muscle torques in total knee arthroplasty with subvastus and parapatellar approaches. Clin Orthop Relat Res 98:189–195

    Article  Google Scholar 

  5. 5.

    Dalury DF, Snow RG, Adams MJ (2008) Electromyographic evaluation of the midvastus approach. J Arthroplasty 23:136–140

    Article  PubMed  Google Scholar 

  6. 6.

    de Haan A, Gerrits KHL, de Ruiter CJ (2009) Counterpoint: the interpolated twitch does not provide a valid measure of the voluntary activation of muscle. J Appl Physiol 107:355–357

    Article  PubMed  Google Scholar 

  7. 7.

    Floren M, Davis J, Peterson MGE, Laskin RS (2007) A mini-midvastus capsular approach with patellar displacement decreases the prevalence of patella baja. J Arthroplasty 22:51–57

    Article  PubMed  Google Scholar 

  8. 8.

    Haas SB, Manitta MA, Burdick P (2006) Minimally invasive total knee arthroplasty: the mini midvastus approach. Clin Orthop Relat Res 452:112–116

    Article  PubMed  Google Scholar 

  9. 9.

    In Y, Kim JM, Choi NY, Kim SJ (2007) Large thigh girth is a relative contraindication for the subvastus approach in primary total knee arthroplasty. J Arthroplasty 22:569–573

    Article  PubMed  Google Scholar 

  10. 10.

    Laskin RS (2007) Surgical exposure for total knee arthroplasty. For everything there is a season. J Anthroplasty 22:12–14

    Article  Google Scholar 

  11. 11.

    Lin HT, Hsu AT, Chang JH, Chien CS, Chang GL (2008) Comparison of EMG activity between maximal manual muscle testing and cybex maximal isometric testing of the quadriceps femoris. J Formos Med Assoc 107:175–180

    Article  PubMed  Google Scholar 

  12. 12.

    Pagnano MW, Meneghini RM (2006) Minimally invasive total knee arthroplasty with an optimized subvastus approach. J Arthroplasty 21(4 Suppl 1):22–26

    Article  PubMed  Google Scholar 

  13. 13.

    Rand JA (1994) The patellofemoral joint in total knee arthroplasty. J Bone Joint Surg Am 76:612–620

    CAS  PubMed  Google Scholar 

  14. 14.

    Schroer WC, Diesfeld PJ, Reedy ME, LeMarr AR (2007) Evaluation of complications associated with 600 mini-subvastus total knee arthroplasties. J Bone Joint Surg Am 89:76–81

    Article  PubMed  Google Scholar 

  15. 15.

    Schroer WC, Diesfeld PJ, Reedy ME, LeMarr AR (2008) Mini-subvastus approach for total knee arthroplasty. J Arthroplasty 23:19–25

    Article  PubMed  Google Scholar 

  16. 16.

    Seyler TM, Bonutti PM, Ulrich SD, Fatscher T, Marker DR, Mont MA (2007) Minimally invasive lateral approach to total knee arthroplasty. J Arthroplasty 22:21–26

    Article  PubMed  Google Scholar 

  17. 17.

    Silva M, Shepherd EF, Jackson WO, Pratt JA, McClung CD, Schmalzried TP (2003) Knee strength after total knee arthroplasty. J Arthroplasty 18:605–611

    Article  PubMed  Google Scholar 

  18. 18.

    Taylor JL (2009) Point: the interpolated twitch does/does not provide a valid measure of the voluntary activation of muscle. J Appl Physiol 107:354–355

    Article  PubMed  Google Scholar 

  19. 19.

    Tria AJ (2000) Surgical principles of total knee replacement: incisions, extensor mechanism, ligament balancing. In: Pellicci PM, Tria AJ, Garvin KL (eds) Orthopaedic knowledge update hip and knee reconstruction, 2nd edn. American Academy of Orthopaedic Surgeons, IL, pp 281–282

    Google Scholar 

  20. 20.

    Tsauo JY, Li WC, Yang RS (2006) Functional outcomes after endoprosthetic knee reconstruction following resection of osteosarcoma near the knee. Disabil Rehabil 28:61–66

    Article  PubMed  Google Scholar 

  21. 21.

    Weinrauch P, Myers N, Wilkinson M, Dodsworth J, Fitzpatrick P, Whitehouse S (2006) Comparison of early postoperative rehabilitation outcome following total knee arthroplasty using different surgical approaches and instrumentation. J Orthop Surg 14:47–52

    CAS  Google Scholar 

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We thank Far Eastern Memorial Hospital for its financial support (FEMH-910030) and National Taiwan University Hospital for providing the Cybex 350 Dynamometer. The authors also thank Dr. Jyh-Lurn Chang, Seattle, USA and Dr. Yuan-Ming Hsu, Taipei, Taiwan, for editing the manuscript.

Conflict of interest statement

The authors have no conflicts of interest. The manuscript has not been presented in any meetings or publications.

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Correspondence to Sheng-Mou Hou.

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Chang, CH., Yang, RS., Chen, KH. et al. Muscle torque in total knee arthroplasty: comparison of subvastus and midvastus approaches. Knee Surg Sports Traumatol Arthrosc 18, 934–938 (2010).

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  • Midvastus approach
  • Muscle torque
  • Total knee replacement
  • Subvastus approach