Skip to main content
Download PDF

The active knee extension after extensor mechanism reconstruction using allograft is not influenced by “early mobilization”: a systematic review and meta-analysis

Journal of Orthopaedic Surgery and Research volume 17, Article number: 153 (2022) Cite this article

Abstract

Background

Postoperative rehabilitation after extensor mechanism reconstruction (EMR) with allograft following total knee arthroplasty (TKA) is not standardized. This meta-analysis aimed to evaluate the effectiveness of early and late knee mobilization after EMR. The range of motion (ROM) and extensor lag in both groups were also assessed as the secondary endpoint.

Methods

Following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines, a systematic review of the literature was performed, including studies dealing with the use of allograft for EMR following TKA. Failure was defined as the persistence of extensor lag > 20°. Coleman Methodology Score and Methodological Index for Non-Randomized Studies (MINORS) score were used to assess the quality of studies included. The failure rate was set as the primary outcome in early (4 weeks) and late (8 weeks) mobilization groups after EMR with allograft. Secondary outcomes were postoperative extensor lag and ROM.

Results

Twelve articles (129 knees) were finally selected for this meta-analysis. Late and early knee mobilization was described in five and seven studies, respectively. No difference was noted between both groups' failure rates (11/84 vs. 4/38, respectively; p = 0.69). The mean extensor lag at last follow-up was 9.1° ± 8.6 in the early mobilization group, and 6.5° ± 6.1 in the late mobilization group is not significantly different (p > 0.05). The mean postoperative knee flexion was 107.6° ± 6.5 and 104.8° ± 7 in the early and late mobilization group, respectively.

Conclusion

While immobilization after EMR in TKA is mandatory to allow tissue healing, early knee mobilization after four weeks can be recommended with no additional risk of failure and increased extensor lag compared to a late mobilization protocol.

Level of evidence

IV, therapeutic study.

Registration

PROSPERO (International Prospective Register of Systematic Reviews): CRD42019141574.

- Introduction

Extensor mechanism (EM) rupture during total knee arthroplasty (TKA) is a serious complication occurring in 0.1–2.5% procedures [1,2,3]. It may lead to a loss of active knee extension with an inability to perform straight-leg raise, which is often followed by a secondary reduction in the range of motion (ROM) complicated by knee instability, chronic pain, and recurrent falls. In turn, the limited knee function may significantly impact and reduce the overall quality of life [4, 5]. Although several surgical techniques have been proposed to approach EM rupture, there is no consensus on the gold standard for EM reconstruction (EMR) [6,7,8,9]. Therefore, the choice of surgical treatment depends on several factors, including the nature and chronicity of disruption, location of the failure, presence or absence of functional loss, general health status, and surgeon expertise [10]. According to the literature, the use of allografts to fill large defects during EMR [7,8,9, 11] has been proven to be effective, mainly due to the inherent mechanical strength of allografts and possibility of representing a fibrous scaffold which can subsequently be colonised by the host tissue. In fact, retrieval studies after EMR have shown incorporation of the host tissue into the allograft, providing insights into the effectiveness of this technique from a biological standpoint [12,13,14,15].

In clinical practice, a 4-week immobilisation period in extension of the knee is mandatory after EMR to allow wound and tissue healing. Weight-bearing restrictions may vary from non-weight bearing to partial weight-bearing, depending on the type of reconstruction performed and the patients’ related factors. The principles introduced by Nazarian and Booth, who first standardised the technique, are universally adopted and have allowed to improve the outcomes compared to previous procedures [16]. Among them, we emphasise the immobilisation of the knee in extension using a cast for 6 weeks, followed by flexion exercises with a 30° increase every 2 weeks, use of an articulated splint for an additional 6 to 12 weeks, and no pulley therapy or work against resistance for the first 6–12 months after removal of the cast. However, it has been argued that immobilisation of the knee for 4 or 8 weeks could generate post-operative stiffness with adherence and arthrofibrosis [17, 18]. Therefore, other authors have proposed early rehabilitation after 4 weeks, but there is no evidence of superiority of a protocol over another.

In this context, we performed a meta-analysis to evaluate the effectiveness of early mobilisation after EMR with allografts. Knee postoperative flexion and extensor lag in the early and late mobilisation groups were also evaluated.

- Materials and methods

- Registration

The protocol was registered online at the International Prospective Register of Systematic Reviews (PROSPERO; CRD42019141574) [19] before commencing the review.

Allografts

The EM was reconstructed using two primary forms of allografts—Achilles tendon with attached calcaneal bone block and complete EM allograft comprising the proximal tibia, the patellar tendon, the patella, and several centimetres of the quadriceps tendon.

Searches

Electronic databases, such as MEDLINE, Scopus, Embase, Web of Science, and Cochrane, were searched for studies investigating EMR in patients who underwent primary or revision TKA. The Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) methodology [20] was employed. A combination of the following keywords was used for article search: ‘Extensor mechanism’ AND ‘Allograft’ And ‘total knee arthroplasty’. The inclusion criteria were not limited to English language literature and specific publication dates. The reference lists of selected articles were searched for additional articles that were not identified in the database search.

Study inclusion and exclusion criteria

Longitudinal studies (retrospective and prospective) and randomised controlled trials evaluating patients treated with allografts and concomitant TKA or revision TKA for EM rupture were included. Case reports, expert opinions, prior systematic reviews, letters to the editor, studies that did not include patients undergoing TKA, studies that included different treatment techniques (such as other allografts, synthetic mesh, or autograft), studies in which the postoperative treatment protocol was not specified, and non-human studies such as in vitro studies and cadaveric studies were excluded.

Study quality assessment

The methodological quality of the included studies was assessed using the Coleman Methodology Score (CMS) and the Methodological Index for Non-Randomized Studies (MINORS) score [21, 22]. Two authors independently determined the CMS and MINORS score. The final scores were obtained through consensus. The CMS was computed by summation of 10 criteria (study size, follow-up period, number of procedures, study type, diagnostic certainty, description of surgical technique, rehabilitation and compliance, outcome criteria, outcome assessment, and selection process), leading to a total possible score of 100. Thus, the CMS ranged from 0 to 100. A higher score was associated with a lower probability that outcomes were caused by chance, bias, or confounding factors. MINORS score is a valid tool designed to assess the methodological quality of non-randomised surgical studies. The maximum MINORS scores for non-comparative and comparative studies were 16 and 24, respectively.

Data extraction strategy

Initially, the titles and abstracts of the studies were screened by two independent reviewers. Full text was obtained for articles whose abstracts meet the inclusion criteria or those without any uncertainty. Then, each study was assessed based on the inclusion criteria by two independent reviewers, and any disagreement regarding inclusion of a particular study was resolved by evaluation of the article by the senior author. Relevant data were extracted from each study. Data on participant demographics, sample size, type of allograft used, site of injury, type of rehabilitation protocol, failure outcomes, and clinical and functional outcomes were recorded.

Rehabilitation protocol

The included patients were divided into two groups based on the rehabilitation protocol adopted. In the first group (early mobilisation), passive and active knee mobilisation was initiated at the end of week 4, followed by a weekly increase of 15°–30° until week 12. In the second group (late mobilisation), mobilisation of the knee was performed 8 weeks after surgical repair, with a weekly increase until week 12. In both groups, a cast or splint was used, and weight-bearing and isometric exercises of the quadriceps were allowed (partially or based on tolerance).

Data synthesis and presentation

The ‘failure rate’ was defined as the percentage of patients presenting a deficit of active knee extension (extensor lag) > 20°. The failure rate, with a 95% confidence interval (CI), was the primary outcome of the rehabilitation protocol after EMR with an allograft. The secondary outcomes were the ROM and extensor lag recorded at the last follow-up. Heterogeneity between studies was tested using the I2 statistic (0–40% = not relevant, 30–60% = moderate, 50–90% = substantial, and 75–100% = considerable). The primary outcome was pooled using random-effects models to determine the effect of interstudy heterogeneity. The chi-square test was used to analyze the significant cross-sectional differences between the two groups for the primary outcome. The two-sample t-test was used to analyze significant differences between the two groups for secondary outcomes. We used Open Meta Analyst (Centre for Evidence Synthesis, RI, USA) and SPSS version 23 (SPSS, Chicago, IL, USA) for all statistical analyses. Statistical significance was set at p ≤ 0.05.

Results

Review statistics

The PRISMA checklist is shown in Fig. 1. A total of 551 potentially relevant studies were identified through a computer search and manual screening of reference lists. After screening the titles and abstracts, the full texts of 50 articles were evaluated. A total of 38 studies were excluded after detailed assessment. The remaining 12 articles were included in the meta-analysis [23,24,25,26,27,28,29,30,31,32,33,34]. Table 1 summarises the characteristics of the included studies. A total of 126 patients (129 knees; weighted mean age, 68.1 ± 4 years) who underwent EMR with an allograft were identified. Among 120 patients, 83 (69%) were women. The weighted mean follow-up period was 3.4 ± 1.2 years.

Fig. 1
figure 1

PRISMA flow chart diagram: search strategy

Full size image
Table 1 Basic Information of the Studies Included in the Systematic review
Full size table

Study quality assessment

The CMS and MINORS score for the included studies are shown in Table 1.

Quantitative synthesis/meta-analysis

All studies included in our meta-analysis clearly described the rehabilitation protocol after the surgical procedure in terms of duration of knee immobilisation in full extension, type (active or passive) and timing of knee mobilisation, and weight-bearing status after the surgical procedure. They all evaluated functional outcomes (extensor lag and range of motion) at the last follow-up (Table 2).

Table 2 Knee mobilization and clinical outcomes
Full size table

Seven studies (84 knees) reported the failure rate of EMR after early mobilisation (4 weeks) in 11 cases, with a pooled failure rate of 10.3% (95% CI 3.1–17.5) and a non-significant interstudy heterogeneity (I2 = 22.96%; p = 0.254; Fig. 2). No difference was observed in the failure rate between early and late mobilisation (11/84 vs. 4/38; p = 0.69).

Fig. 2
figure 2

Early mobilization failure rate: forest plot describing the failure rate in case of early mobilization

Full size image

Five studies (45 knees) reported the failure rate of EMR after late mobilisation (8 weeks). Failure of EMR was reported in 11 cases, and the corresponding pooled failure rate was 28% (95% CI 5.9–61.6), with a high heterogeneity between the included studies (I2 = 94.2%; p < 0.001). After exclusion of the outlier study by Leopold et al., the pooled failure rate decreased to 7.7% (95% CI 0.2–15.5), and the interstudy heterogeneity became nonsignificant (I2 = 0%; p = 0.512; Fig. 3).

Fig. 3
figure 3

Late mobilization failure rate: forest plot describing the failure rate in case of late mobilization

Full size image

The weighted mean extensor lag at the last follow-up was 6.5° ± 6.1° and 9.1° ± 8.6° for late and early mobilisation, respectively. No differences in extensor lag were noted between the two groups (p = 0.575).

Based on the available data, the postoperative weighted mean knee flexion was not significantly different between the two groups, but early mobilisation was associated with higher knee flexion at the longest follow-up than late mobilisation (107.6° ± 6.5° vs. 104.8° ± 7°; p = 0.495).

With regard to complications, in the early mobilisation group, we found four re-ruptures and five infections, while in the late mobilisation group, we found four re-ruptures and two infections, with no statistically significant difference between the two groups (p = 0.778 for re-ruptures and p = 0.515 for infections).

- Discussion

Although EMR using allografts has the potential to improve EM function, augment host tissue, maintain ROM, and decrease dependence on walking aids, the postoperative rehabilitation protocol has not been standardised.

Immobilisation of the knee in full extension for a period of 4–8 weeks has been recommended for several reasons. First, the use of allografts requires immobilisation of the knee after surgery to promote healing of superficial and deep tissue and osteointegration of the graft in a weakened host tissue [12, 35]. Second, wound healing is an important parameter to be considered after this type of surgery, and early mobilisation of the knee during the initial post-operative days could stress superficial and deep tissues and consequently induce wound complications, especially in patients undergoing revision surgery [36,37,38].

However, prolonged post-operative immobilisation could also result in excessive scarring, with arthrofibrosis and joint stiffness [17]. Therefore, many surgeons have described an ‘early’ post-operative knee mobilisation after a 4-week period, promoting stretching of the muscle fibres with elongation of sarcomeres and a higher chance of recovering greater muscular strength at follow-up [39]. Nevertheless, early mobilisation could also stretch the tendon fibres of allografts, with a risk of elongation of the tendon and an incomplete return to its original length, especially in elderly patients [40].

This meta-analysis showed that early knee mobilisation was not associated with an increased risk of an extensor lag > 20°, with a failure rate of 10.3% and 7.7% in the early and late mobilisation groups, respectively. Therefore, our results suggest that early mobilisation does not negatively impact active knee extension at follow-up. Notably, in this study, we arbitrarily decided to exclude the study by Leopold et al. from the early mobilisation group; it described treatment failure in all six patients treated with EMA allografts [29]. The authors obtained mediocre outcomes with marked residual deficiencies in active knee extension mainly due to inadequate allograft tension, which allowed a flexion of approximately 60°.

The results of this study are in line with those presented by Boettner et al., who described the beginning of passive knee flexion through the application of continuous passive motion the day after the surgery or as soon as the soft tissue allowed [24]. The authors did not report any failures at follow-up.

Based on available data, the post-operative rehabilitation regimen does not influence extensor lag and ROM at follow-up, although early mobilisation has been reported to be associated with a greater knee flexion range at follow-up; therefore, late knee mobilisation after EMR with an allograft seems unnecessary.

The strengths and potential limitations of this study must be acknowledged. To the best of our knowledge, this is the first meta-analysis to evaluate the effectiveness of early mobilisation after EMR with an allograft in terms of failure rate, post-operative extensor lag, and knee flexion. First, this meta-analysis was performed on level II or level IV small case series. Second, the lack of standardisation between studies regarding the site of rupture, surgical technique, type of fixation, and postoperative protocols may have contributed to the heterogeneity of results between studies. This limitation prevented us from drawing a solid conclusion regarding the best postoperative rehabilitation protocol.

- Conclusion

In conclusion, immobilisation after EMR is mandatory to allow tissue healing, but knee mobilisation after 4 weeks can be performed without a higher risk of failure and increased extensor lag compared to mobilisation after 8 weeks. However, early mobilisation is associated with a greater knee flexion range at follow-up.

Availability of data and materials

Not applicable.

Abbreviations

ROM:

Range of motion

TKA:

Total knee arthroplasty

EM:

Extensor mechanism

ATA:

Achilles tendon allograft

EMA:

Extensor mechanism allograft

CMS:

Coleman Methodology Score

MINORS:

Methodological Index for Non-randomized Studies

CPM:

Continuous passive motion

References

  1. Lynch AF, Rorabeck CH, Bourne RB. Extensor mechanism complications following total knee arthroplasty. J Arthroplasty. 1987;2:135–40. https://doi.org/10.1016/s0883-5403(87)80020-7.

    Article  CAS  PubMed  Google Scholar 

  2. Papalia R, Vasta S, D’Adamio S, et al. Complications involving the extensor mechanism after total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc. 2015. https://doi.org/10.1007/s00167-014-3189-9.

    Article  PubMed  Google Scholar 

  3. Rand JA, Morrey BF, Bryan RS. Patellar tendon rupture after total knee arthroplasty. Clin Orthop Relat Res. 1989;244:233–8.

    Article  Google Scholar 

  4. Schoderbek RJJ, Brown TE, Mulhall KJ, et al. Extensor mechanism disruption after total knee arthroplasty. Clin Orthop Relat Res. 2006;446:176–85. https://doi.org/10.1097/01.blo.0000218726.06473.26.

    Article  PubMed  Google Scholar 

  5. Ellanti P, Moriarity A, Wainberg N, Ni Fhoghlu C, McCarthy T. Association between patella spurs and quadriceps tendon ruptures. MLTJ. https://doi.org/10.11138/mltj/2015.5.2.088

  6. Ellanti P, Moriarity A, Nagle M, McCarthy T. Outcomes after quadriceps tendon repair in patients over 80 years of age. MLTJ, 224–7. https://doi.org/10.11138/mltj/2016.6.2.224 (Corÿdon Hochheim M, Bartels EM, Vestergård Iversen J. Quadriceps Tendon rupture. Anchor or transosseous suture? A systematic review MLTJ, 356–62. https://doi.org/10.32098/mltj.03.2019.09)

  7. Bonnin M, Lustig S, Huten D. Extensor tendon ruptures after total knee arthroplasty. Orthop Traumatol Surg Res. 2016;102(1 Suppl):S21-31. https://doi.org/10.1016/j.otsr.2015.06.025.

    Article  CAS  PubMed  Google Scholar 

  8. Maffulli N, Spiezia F, La Verde L, et al. The management of extensor mechanism disruption after total knee arthroplasty: a systematic review. Sports Med Arthrosc. 2017;25:41–50. https://doi.org/10.1097/JSA.0000000000000139.

    Article  PubMed  Google Scholar 

  9. Schliemann B, Grüneweller N, Yao D, et al. Biomechanical evaluation of different surgical techniques for treating patellar tendon ruptures. Int Orthop. 2016;40:1717–23. https://doi.org/10.1007/s00264-015-3003-4.

    Article  PubMed  Google Scholar 

  10. Complex ruptures of the quadriceps tendon: a systematic review of surgical procedures and outcomes. Oliva F, Marsilio E, Migliorini F, Maffulli N. J Orthop Surg Res. 2021 Sep 4;16(1):547. doi: https://doi.org/10.1186/s13018-021-02696-9

  11. Vajapey SP, Blackwell RE, Maki AJ, Miller TL. Treatment of Extensor tendon disruption after total knee arthroplasty: a systematic review. J Arthroplasty. 2019;34:1279–86. https://doi.org/10.1016/j.arth.2019.02.046.

    Article  PubMed  Google Scholar 

  12. Burnett RSJ, Fornasier VL, Haydon CM, et al. Retrieval of a well-functioning extensor mechanism allograft from a total knee arthroplasty. Clinical and histological findings. J Bone Joint Surg Br 2004;86:986–990. https://doi.org/10.1302/0301-620x.86b7.15182]. Even though EM allografts have considerable mechanical and biological properties, the post-operative rehabilitation protocol is not standardized

  13. Serino J, Mohamadi A, Orman S, et al. Comparison of adverse events and postoperative mobilization following knee extensor mechanism rupture repair: a systematic review and network meta-analysis. Injury. 2017;48:2793–9. https://doi.org/10.1016/j.injury.2017.10.013.

    Article  PubMed  Google Scholar 

  14. Diaz-Ledezma C, Orozco FR, Delasotta LA, et al. Extensor mechanism reconstruction with achilles tendon allograft in TKA: results of an abbreviate rehabilitation protocol. J Arthroplasty. 2014;29:1211–5. https://doi.org/10.1016/j.arth.2013.12.020.

    Article  PubMed  Google Scholar 

  15. Busfield BT, Ries MD. Whole patellar allograft for total knee arthroplasty after previous patellectomy. Clin Orthop Relat Res. 2006;450:145–9. https://doi.org/10.1097/01.blo.0000223980.44455.21.

    Article  PubMed  Google Scholar 

  16. Nazarian DG, Booth REJ. Extensor mechanism allografts in total knee arthroplasty. Clin Orthop Relat Res. 1999;367:123–9.

    Article  Google Scholar 

  17. Cheuy VA, Foran JRH, Paxton RJ, et al. Arthrofibrosis associated with total knee arthroplasty. J Arthroplasty. 2017;32:2604–11. https://doi.org/10.1016/j.arth.2017.02.005.

    Article  PubMed  Google Scholar 

  18. González Della Valle A, Leali A, Haas S. Etiology and surgical interventions for stiff total knee replacements. HSS J. 2007;3:182–9. https://doi.org/10.1007/s11420-007-9053-4.

    Article  PubMed  PubMed Central  Google Scholar 

  19. Balato G, De Franco C, de Matteo VBA. Extensor mechanism reconstruction using allograft in total knee arthroplasty: a systematic review and meta-analysis. PROSPERO CRD42019141574

  20. Liberati A, Altman DG, Tetzlaff J, et al. The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration. J Clin Epidemiol. 2009;62:e1-34. https://doi.org/10.1016/j.jclinepi.2009.06.006.

    Article  PubMed  Google Scholar 

  21. Slim K, Nini E, Forestier D, et al. Methodological index for non-randomized studies (minors): development and validation of a new instrument. ANZ J Surg. 2003;73:712–6. https://doi.org/10.1046/j.1445-2197.2003.02748.x.

    Article  PubMed  Google Scholar 

  22. Coleman BD, Khan KM, Maffulli N, et al. Studies of surgical outcome after patellar tendinopathy: clinical significance of methodological deficiencies and guidelines for future studies. Victorian Institute of Sport Tendon Study Group. Scand J Med Sci Sports. 2000;10:2–11. https://doi.org/10.1034/j.1600-0838.2000.010001002.x.

    Article  CAS  PubMed  Google Scholar 

  23. Ares O, Lozano LM, Medrano-Nájera C, et al. New modified Achilles tendon allograft for treatment of chronic patellar tendon ruptures following total knee arthroplasty. Arch Orthop Trauma Surg. 2014;134:713–7. https://doi.org/10.1007/s00402-014-1951-6.

    Article  PubMed  Google Scholar 

  24. Boettner F, Bou MJ. Achilles tendon allograft for augmentation of the Hanssen patellar bone grafting. Knee Surg Sports Traumatol Arthrosc. 2015;23:1035–8. https://doi.org/10.1007/s00167-014-2845-4.

    Article  PubMed  Google Scholar 

  25. Burnett RSJ, Berger RA, Paprosky WG, et al. Extensor mechanism allograft reconstruction after total knee arthroplasty. A comparison of two techniques. J Bone Joint Surg Am. 2004;86:2694–9. https://doi.org/10.2106/00004623-200412000-00016.

    Article  PubMed  Google Scholar 

  26. Crossett LS, Sinha RK, Sechriest VF, Rubash HE. Reconstruction of a ruptured patellar tendon with achilles tendon allograft following total knee arthroplasty. J Bone Joint Surg Am. 2002;84:1354–61. https://doi.org/10.2106/00004623-200208000-00010.

    Article  PubMed  Google Scholar 

  27. Burnett RSJ, Butler RA, Barrack RL. Extensor mechanism allograft reconstruction in TKA at a mean of 56 months. Clin Orthop Relat Res. 2006;452:159–65. https://doi.org/10.1097/01.blo.0000238818.25530.2b.

    Article  CAS  PubMed  Google Scholar 

  28. Emerson RHJ, Head WC, Malinin TI. Extensor mechanism reconstruction with an allograft after total knee arthroplasty. Clin Orthop Relat Res. 1994;303:79–85.

    Article  Google Scholar 

  29. Leopold SS, Greidanus N, Paprosky WG, et al. High rate of failure of allograft reconstruction of the extensor mechanism after total knee arthroplasty. J Bone Joint Surg Am. 1999;81:1574–9. https://doi.org/10.2106/00004623-199911000-00009.

    Article  CAS  PubMed  Google Scholar 

  30. Lim CT, Amanatullah DF, Huddleston JI 3rd, et al. Reconstruction of disrupted extensor mechanism after total knee arthroplasty. J Arthroplasty. 2017;32:3134–40. https://doi.org/10.1016/j.arth.2017.05.005.

    Article  CAS  PubMed  Google Scholar 

  31. Malhotra R, Garg B, Logani V, Bhan S. Management of extensor mechanism deficit as a consequence of patellar tendon loss in total knee arthroplasty: a new surgical technique. J Arthroplasty. 2008;23:1146–51. https://doi.org/10.1016/j.arth.2007.08.011.

    Article  PubMed  Google Scholar 

  32. Rajgopal A, Vasdev A, Dahiya V. Patellar tendon reconstruction in total knee arthroplasty: a new technique. J Knee Surg. 2015;28:483–8. https://doi.org/10.1055/s-0034-1390332.

    Article  PubMed  Google Scholar 

  33. Wise BT, Erens G, Pour AE, et al. Long-term results of extensor mechanism reconstruction using Achilles tendon allograft after total knee arthroplasty. Int Orthop. 2018;42:2367–73. https://doi.org/10.1007/s00264-018-3848-4.

    Article  PubMed  Google Scholar 

  34. Wood TJ, Leighton J, Backstein DJ, et al. Synthetic graft compared with allograft reconstruction for extensor mechanism disruption in total knee arthroplasty: A Multicenter Cohort Study. J Am Acad Orthop Surg. 2019;27:451–7. https://doi.org/10.5435/JAAOS-D-18-00393.

    Article  PubMed  Google Scholar 

  35. Lamberti A, Balato G, Summa PP, et al. Surgical options for chronic patellar tendon rupture in total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc. 2018;26:1429–35. https://doi.org/10.1007/s00167-016-4370-0.

    Article  PubMed  Google Scholar 

  36. Garbedian S, Sternheim A, Backstein D. Wound healing problems in total knee arthroplasty. Orthopedics. 2011;34:e516–8. https://doi.org/10.3928/01477447-20110714-42.

    Article  PubMed  Google Scholar 

  37. Johnson DP, Eastwood DM, Bader DL. Biomechanical factors in wound healing following knee arthroplasty. J Med Eng Technol. 1991;15:8–14. https://doi.org/10.3109/03091909109015442.

    Article  CAS  PubMed  Google Scholar 

  38. Scuderi GR. Avoiding postoperative wound complications in total joint arthroplasty. J Arthroplasty. 2018;33:3109–12. https://doi.org/10.1016/j.arth.2018.01.025.

    Article  PubMed  Google Scholar 

  39. Opplert J, Babault N. Acute effects of dynamic stretching on muscle flexibility and performance: an analysis of the current literature. Sports Med. 2018;48:299–325. https://doi.org/10.1007/s40279-017-0797-9.

    Article  PubMed  Google Scholar 

  40. Lavagnino M, Bedi A, Walsh CP, et al. Tendon contraction after cyclic elongation is an age-dependent phenomenon. in vitro and in vivo comparisons. Am J Sports Med. 2014;42:1471–7. https://doi.org/10.1177/0363546514526691.

    Article  PubMed  Google Scholar 

Download references

Acknowledgements

We thank Prof. Dr. Massimo Mariconda (University Federico II of Naples) for helping us in statistical analysis and in the drafting of the manuscript.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Author information

Authors and Affiliations

  1. Department of Public Health, Orthopedic Unit, “Federico II” University, Via Sergio Pansini, 5 80130, Naples, Italy

    Cristiano De Franco, Vincenzo de Matteo, Marco Lenzi, Ernesto Marano, Enrico Festa, Alessio Bernasconi, Francesco Smeraglia & Giovanni Balato

Authors
  1. Cristiano De Franco
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Vincenzo de Matteo
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Marco Lenzi
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Ernesto Marano
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Enrico Festa
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Alessio Bernasconi
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Francesco Smeraglia
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Giovanni Balato
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

ML and AB screened the studies and selected the data. AB and FS evaluated the quality of the studies. GB, CDF wrote the manuscript. EM, EF and VdM corrected the whole paper. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Giovanni Balato.

Ethics declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

No author is involved in conflict of interest. No author has received any funding.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and Permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

De Franco, C., de Matteo, V., Lenzi, M. et al. The active knee extension after extensor mechanism reconstruction using allograft is not influenced by “early mobilization”: a systematic review and meta-analysis. J Orthop Surg Res 17, 153 (2022). https://doi.org/10.1186/s13018-022-03049-w

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1186/s13018-022-03049-w

Keywords

Journal of Orthopaedic Surgery and Research

ISSN: 1749-799X