Management of Iatrogenic Medial Collateral Ligament Injury in Primary Total Knee Arthroplasty: A Systematic Review

Abstract

Objectives:

The medial collateral ligament (MCL) injury is one of the possible complications of primary total knee arthroplasty (TKA), which can lead to coronal-plane instability that requires surgical revision. Injured MCL can result in joint instability and polyethylene wear. Different strategies have been proposed for MCL reconstruction based on the location of the injury. However, there is a lack of clarity regarding the optimal method for handling an iatrogenic MCL injury throughout a TKA.

Methods:

A PRISMA flow diagram was used to guide the systematic literature review. An extensive search was conducted in PubMed, Embase, Scopus, Web of Science, and Google Scholar. Newcastle Ottawa scale checklist was used to assess the methodological quality of the articles.

Results:

A total of 19 qualitative studies, including non-cadaveric patients with MCL injury during TKA, were identified after analyzing the full text of the articles. All included studies were either retrospective, observational cohort or case series. A total of 486 patients were studied to gather information on the methods used to repair the MCL and their results. Most injuries arose in the tibial attachment, which surgeons mostly realized during the final stages of surgery. Used techniques can be categorized into three main groups: Primary repair, Repair with augmentation, and changing prosthesis characteristics.

Conclusion:

This systematic review demonstrated that the most popular management of iatrogenic MCL injury was using suture anchors, staples, screws and washers, and more constrained prostheses. The proper method should be decided considering the site of the MCL injury.

Introduction

Iatrogenic injury of the medial collateral ligament (MCL) during primary total knee arthroplasty (TKA) can lead to coronal-plane instability, which may require revision TKA if left untreated.^1-5 The incidence of iatrogenic MCL injuries ranges from 0.77 to 2.7% in TKA patients (2.4), and it may reach 8% among obese patients.⁵ An injured MCL can result in knee instability, which can accelerate the polyethylene wear. Additionally, a lack of MCL leads to pain and decreased postoperative function of the knee.^3,6,7

Iatrogenic MCL injury occurs at various sites, such as mid-substance,⁶ tibial insertion,^8,9 and femoral insertion.¹⁰ There are two main categories of risk factors for iatrogenic MCL injury during TKA: patient-related factors and surgeon-related factors. The patient-related factors such as severe varus deformities, associated sagittal deformities such as fixed flexion deformities, knee stiffness, osteoporosis, and obesity are associated with an increased risk of MCL injuries.¹¹ There are also surgeon-related factors such as hyper-flexing the knees during the exposure, failing to remove tenting medial osteophytes beneath the MCL, not protecting the MCL while handling the oscillating sawblade, incorrectly balanced MCLs, insertion of thick trial meniscus components, retraction in hyperflexion, and forceful extension increase the risk of intraoperative MCL injury.^4,12

There is still ongoing debate surrounding the most effective approach for handling intraoperative MCL injury. The treatment options could be categorized into three main groups ranging from 1) primary repair, including using suture or staple only,^2,13,14 fixing with screws and washer construct,¹³ or using suture anchors,¹² 2) repair with augmentation using autograft⁶ or synthetic ligament,¹⁵ or meniscus transfer,¹⁶ 3) changing prosthesis characteristic such as thicker polyethylene insert,^12,17 or conversion to the constrained prosthesis.^3,12 Although various approaches exist for managing iatrogenic MCL injuries in TKA, there is still no agreement on the best approach when it comes to the site of injury. As such, this study aimed to assess all possible techniques that can be utilized in this context.

Materials and Methods

In accordance with PRISMA (18), articles were screened against eligibility criteria prior to performing the systematic review. In this study, the researchers identified patients who experienced an intraoperative iatrogenic MCL injury while undergoing primary TKA using data obtained from the existing literature. During these primary TKA, the MCL was injured intraoperatively as an inadvertent intraoperative event. Observational studies were considered retrospectively and prospectively since randomized trials were not anticipated. To find non-cadaveric original articles across a wide range of databases without limiting language, a search strategy was developed. An assessment of the quality scores of included studies was done using the Newcastle-Ottawa Scale.

Search Strategy

The following keywords were used during the period from conception to March 2023 by an independent investigator (AM) to search PubMed, Embase, Scopus, Web of Science, and Google Scholar: ("knee arthroplasty" OR "knee replacement" OR "TKA") AND ("MCL" OR "medial collateral ligament" OR "collateral ligament") as well as MeSH terms.

Eligibility and Study Selection

We included all studies investigating the iatrogenic MCL injury during TKA in any language. Exclusion criteria were 1) case reports, 2) reviews (narrative, systematic, or meta-analyses), 3) cadaveric studies, 4) animal studies, 5) consensus statements and guidelines, 6) editorial notes, letters, and conference abstracts, 7) studies with insufficient data. Two independent authors (AP and SA) reviewed every report.

Results

The flowchart for this systematic review can be found in [Figure 1]. We used PubMed, Scopus, Embase, Web of Science, and Google Scholar in the initial search. A total of 2,132 articles were found during the initial search, including 381 articles from PubMed, 820 from Scopus, 427 from Embase, 382 from Web of Science, and 122 from Google Scholar. A total of 1,145 articles were removed by Endnote software as duplicate articles. Due to inappropriate study types and inappropriate study participants, 927 out of 987 reports were excluded as a result of the title and abstract screening and application of the exclusion criteria. Upon evaluating the full text of the studies, 19 qualitative studies were identified. A summary of the study and patients' characteristics is shown in [Table 1]. An evaluation was conducted on 19 retrospective studies, including 486 patients. [Table 2] contains more details about the information that we went over and selected from the articles. Iatrogenic MCL injuries occur at three sites: tibial insertion, femoral insertion, and mid-substance. As shown in [Table 3], in most studies, most injuries arise in the tibial attachment, which surgeons may realize during the final stages of surgery. The most popular techniques were primary repair and augmentation, suture anchors, staples, screws and washers, and more constrained prostheses.

Figure 1.

Study selection based on the Preferred Reporting Items for Systematic Reviews (PRISMA) 2018 statement

Table 1.

Characteristics of the included studies

Male/Female, %	Age (y),Mean or Range	Follow-up Period (months)	No. of Cases	Study Design, Patient Enrollment	Study Period	Country	Year	Lead Author
4/96	67 (59–74)	24	43	Prospective, consecutive	January 2003 to December 2015	China	2022	Jin et al.9
14.28/85.75	67.3±6.6	24	14	Prospective, consecutive	January 2016 to 2018	China	2021	Liu et al.21
21.42/78.58	72.6±3.9	24	14	Prospective, consecutive	January 2009 to December 2016	China	2021	Li et al.22
18/82	64.2 ± 5.64	24	11	Prospective, consecutive	January 2014 to November 2019	China	2020	Sun et al.16
17.1/82.9	65.22 ± 7.97	24	41	Prospective, consecutive	January 2011 to December 2015	India	2020	Rajkumar et al.10
5.6/94.4	68±5	24	35	Prospective, consecutive	2007 to 2017	Iran	2020	Motiffard et al.23
14.28/85.75	63.6 (49–79)	15.6	14	Prospective, consecutive	March 2018 and March 2019	China	2020	Ni et al.25
30.3/69.7	63.6 (8.95)	24	33	Prospective, consecutive	2005 to 2015	USA	2019	White et al.20
NA	71.4±7.8	24	65	Prospective, consecutive	January 2003 to June 2014	South Korea	2019	Jin et al.24
0/100	67.4 ± 6.0	24	53	Prospective, consecutive	January 2001 to February 2006	South Korea	2018	Choi et al.8
23.52/76.48	63.0±4.2	24	17	Prospective, consecutive	2007 to 2013	China	2017	Wang et al.26
13/87	66.5 ± 9.7	24	23	Prospective, consecutive	January 2003 and December 2009	USA	2016	Siqueira et al.4
18.18/81.82	64.3 (55-77)	24	11	Prospective, consecutive	March 2009 to May 2014	China	2016	Cao et al.27
15.55/84.45	85.22	24	45	Prospective, consecutive	1991 to 2009	USA	2016	Bohl et al.13
NA	64 (43-85)	12 ± 5	11	Prospective, consecutive	January 2003 and November 2012 a	USA	2014	Shahi et al.15
NA	64.8	12	10	Prospective, consecutive	2005 to 2012	Romania	2013	Dragosloveanu et al.12
NA	58	NA	9	NA	5 years	USA	2012	Stephens et al.14
48.64/51.36	60	24	37	Prospective, consecutive	1998 to 2004	USA	2010	Lee et al.3
28.57/71.43	63 (47-86)	45	14	Prospective, consecutive	June 1991 to June 1997	USA	2001	Leopold et al.2

Table 2.

Newcastle-Ottawa scale of the included studies

Total	Exposure	Comparability	Selection
7	★★	★★	★★★		Sun et al.16
7	★★	★★	★★★		Jin et al.9
7	★★	★★	★★★		Rajkumar et al.10
7	★★	★★	★★★		Motiffard et al.23
7	★★	★★	★★★		Liu et al.21
7	★★	★★	★★★		Li et al.22
7	★★	★★	★★★		Ni et al.25
7	★★	★★	★★★		White et al.20
7	★★	★★	★★★		Jin et al.24
7	★★	★★	★★★		Choi et al.8
7	★★	★★	★★★		Wang et al.26
7	★★	★★	★★★		Siqueira et al.4
7	★★	★★	★★★		Cao et al.27
7	★★	★★	★★★		Bohl et al.13
7	★★	★★	★★★		Shahi et al.15
7	★★	★★	★★★		Dragosloveanu et al.12
7	★★	★★	★★★		Stephens et al.14
7	★★	★★	★★★		Lee et al.3
6	★★	★	★★★		Leopold et al.2

Table 3.

Details of the included studies

Lead author	Year	Method of repair	No. of patients	Site of injury	Phase of injury	KSS**	KSF***	No. of revisions
Jin9	2022	Suture anchor	43	tibial attachment	final stage of surgery	NA*	86_3 ± 8.1	0
Liu21	2021	Suture anchor	14	tibial attachment	final stage of surgery	87.6 ± 2.7	NA*	1
Li	2021	Suture anchor	14	9 mid-substance 5 femoral attachment	NA*	93.3±4.7	NA*	NA*
Sum.16	2020	Aaugmentation of medial meniscus transfer_	11	tibial attachment	final stage of surgery	95 ± 4.47	91.8± 7.5	0
Rajkumar10	2020	Screw and washer construct	41	femoral attachment	final stage of surgery	80 to 90	80 to 95	0
Motiffard23	2020	Suture	35	mid-substance	trial reduction or in the final stages of surgery	81 ± 17	61 ± 13	3
Ni25	2020	Screw and rectangular spiked washer	14	femoral attachment	final stage of surgery	NA*	NA*	0
White20	2019	Staple	33	tibial attachment	NA*	NA*	NA*	0
Jin (a)24	2019	Suture anchor	36	tibial attachment	final stage of surgery	86.4 ± 7.2	NA*	0
Jin(b)24	2019	Staple	29	tibial attachment	final stage of surgery	88.3 ± 7.5	NA*	0
Choi8	2017	Suture anchor	40	tibial attachment	final stage of surgery	23.3 to 92.7	69.9± 8.4	3
Wang26	2017	MCL reconstruction without a constrained	17	12 mid-substance, 5 femoral attachment	final stage of surgery	NA*	84.7± 5.9	0
Siqueira4	2016	Unconstrained with repair	10	NA*	NA*	79.2 ± 21.6	78.1 ± 22	0
Siqueira4	2016	Constrained with repair	3	NA*	NA*	50 ± 36	51.7 ± 20.8	0
Siqueira4	2016	Constrained	8	NA*	NA*	91.1 ± 10.5	59.3 ± 20.3	0
Cao27	2016	Semitendinosus and gracilis tendon	11	tibial attachment	final stage of surgery	89.82 ± 3.76	89.54 ± 3.50	0
Bohl13	2016	Femur avulsion was repaired using suture with a screw-and-washer construct of the avulsions tibia avulsion, 4 with suture alone, 9 with suture anchors, and 7 with suture with a screw-and-washer construct A cruciate-retaining prosthesis was used in 35 total knee arthroplasties, and a posterior stabilized prosthesis was used in 10	45	24 mid-substance, 20 tibial attachment 1 femoral attachment	final stage of surgery	NA*	NA*	5
Shahi15	2014	Synthetic ligament	11	tibial attachment	final stage of surgery	76to 100	NA*	0
Dragosloveanu12	2013	7 suture anchor 3 constrained tibial	10	7 mid-substance 3 tibial attachment	final stage of surgery	87.71	NA*	1
Stephens14	2012	Primary repair	9	mid-substance	NA*	NA*	73.3	0
Lee3	2010	Increased constraint	37	28 mid-substance, 9 tibial attachment	final stage of surgery	NA*	83	3
Leopold2	2001	Primary repair	14	mid-substance	NA*	93	NA*	0

*Not applicable, **Knee Society Score (KSS), ***Knee Functional Score (KFS)

Discussion

Injury to MCL during TKA is often unrecognized and rarely discussed. Due to its iatrogenic nature, prospective controlled studies were not found in the search. Based on the included studies site of injury and phase of detection could be possible influential factors for choosing the best repair techniques. Although sex, age, body mass index, and being a professional athlete may be influential factors, they were not mentioned in studies. Knee instability, accelerated wear, loosening, and revision surgery may result from unrecognized MCL injury.^18,19

1) Primary Repair:

Mid-substance disruption of the MCL can be treated with primary repair and postoperative bracing.²

A.Staple or Suture Only

A study conducted by White et al.²⁰ found that using staples to repair iatrogenic MCL injuries in tibial insertion had better functional outcomes and satisfaction compared to those who underwent revision TKA for instability and those who underwent TKA without MCl injury. However, 19.2% of patients with the staple repair were found to have instability.

B. Suture Anchor

For repairing iatrogenic injuries, Jin et al.⁹, Liu et al.²¹, Li et al.²² and Motififard et al.²³ used suture anchors. The study conducted by Jin et al. involved an injury to the tibial attachment site, whereas Motififard's involved an injury to the mid-substance. As reported in the study by Jin et al., the results after two years of follow-up in the injury group were similar to those in the control group without iatrogenic injury of MCL.

In the study carried out by Motififard et al., however, results were not satisfactory, and 15% of the repairing group had instability. Choi et al. also reported an identical survival rate for the patient and control groups after 13 years.⁸

Nevertheless, in the research by Jin et al. (2019)²⁴ which the suture anchor and staple groups were compared in MCL injury at tibial insertion, no difference was observed regarding the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and Knee Society Score (KSS). Furthermore, no statistically significant difference in stability was found between the suture anchor and staple groups.

C) Screw and Washer

In studies by Ni et al.²⁵ and Rajkumar et al.,¹⁰ it was demonstrated that femoral bony MCL avulsions during TKA could be repaired using screw and washer constructs. As a result, the excellent clinical and radiological outcomes achieved through this approach obviated the necessity for augmenting constraints. One or two K-wires were used to hold the avulsed fragment and attach the MCL in place. Depending on the fragment size, a cancellous screw with a washer of 3.5 mm was inserted when the knee was in 30 degrees of flexion.

2) Augmentation with Autograft

a. Autograft (Semitendinosus or Gracilis)

An augmentation with autograft of the semitendinosus tendon was used in the study by Wang et al.²⁶ for primary double-bundle MCL reconstruction without constrained components. In 12 cases, the MCL injury was midsection, while in five cases, it was avulsed from the femur metaphysis. The authors demonstrated that TKA without a constrained implant produces excellent results when repairing MCL injuries. In the study by Cao et al.,²⁷ which used both semitendinosus and gracilis tendon in MCL injuries at the joint level, the same result was shown. According to their latest follow-up, both groups had comparable KSS and functional scores.

b. Synthetic Grafts

The mid-substance MCL injuries in the study by Shahi et al.¹⁵ occurred due to direct injury from either an oscillating saw blade or sharp instruments used for medial subperiosteal lifting. The MCL was exposed during the procedure, and a synthetic ligament (NeoligamentsTM, Xiros Company, Leeds, UK) was utilized. This synthetic ligament is constructed with parallel longitudinal polyester fibers, forming an open mesh scaffold structure that facilitates tissue growth. To secure the synthetic ligament to the tibia, nonabsorbable sutures were employed to suture the graft onto the medial aspect, commencing proximally from the medial epicondyle. Additionally, the femoral and tibial attachments were sutured using deep interrupted sutures to the periosteum.

c. Meniscus Transfer

A medial meniscus transfer is another effective method. In the study by Sun,¹⁶ this method was used for the first time for iatrogenic MCL injury in tibial attachment, and it showed excellent results in clinical outcomes of the injury group and the KSS and knee functional score (KSF).

3) Changing Prosthesis Characteristics

a. Thicker Polyethylene

During the study by Koo,¹⁷ thicker polyethylene was inserted to achieve balance and stability in the mediolateral soft tissue at 0°, 30°, and 90° of knee flexion following the detection of the intraoperative MCL injury from the tibial attachment site. It was generally recommended to use a 2-mm to 4-mm thicker polyethylene insert compared to the initial one to stabilize the knee joint and allow some degree of lateral tightness. Standing anteroposterior radiography showed almost 4° more valgus in the tibiofemoral angle in the MCL-off knees than the MCL-intact side. However, there were no complaints of knee instability in daily activities.

b. Conversion to the Constrained Prosthesis

Conversion into constrained prostheses is the most popular strategy. As this method was used in a study performed by Lee,³ patients with increased constraint (TCIII; DePuy) had similar scores to those without ligament injuries during TKA. Among the MCL disruptions observed, 28 cases were characterized by transection of the ligament, while nine cases involved avulsion of the collateral ligament from the tibial metaphysis. Four patients were revised for instability among the seven who did not receive more constrained prostheses.

Otherwise, in a study conducted by Siqueira,⁴ treatment of the MCL injury was determined by the surgeon and consisted of using an unconstrained implant with (n=10) or without (n=2) primary ligament repair, a constrained implant with (n=3) or without (n=8) ligament repair. One patient had an avulsion from the tibial metaphysis, while the other 22 patients had mid-substance injuries. Baseline KSS varied among the four treatment groups, but postoperative KSS

scores showed no significant differences. Preoperative and postoperative KFS did not differ among the treatment groups. The difference between preoperative and postoperative KSS scores was significant, but not for KFS scores. When comparing preoperative KSS scores and the difference between pre-and postoperative KSS scores, pairwise comparisons between the groups revealed no statistically significant differences.

The mentioned techniques demonstrated various outcomes in different studies. These variations could be due to different patient demographics, surgeons, and follow-up methods. However, one of the main determinants was the site of injury. As mentioned, most of the studies evaluate MCL avulsion from tibial insertion. Primary repairs, staples, suture anchors, augmentation with autograft, and changing prosthesis characteristics were used for these patients. In contrast to tibial insertion injuries, fewer studies reported femoral insertion injuries, but the Screw and washer technique has shown a proper outcome for these patients. In addition, primary repair and augmentation with autografts are preferred in mid-substance injuries.

Conclusion

Suture anchors, staples, screws and washers, and more constrained prostheses were the most common techniques of iatrogenic MCL injury management reported in the literature. However, the decision over the optimal strategy to manage the MCL injury during TKA should be made considering the site of the MCL injury.