OPINION
ANDERSON, Justice.This dispute presents the question of whether a prior disability that does not affect an employee’s ability to secure employment may be considered when determining whether the employee is eligible for permanent-total-disability benefits under Minn.Stat. § 176.101, subd. 5(2) (2014). The Workers’ Compensation Court of Appeals (WCCA) concluded that, when determining eligibility for permanent-total-disability benefits, any disability may contribute to the employee’s permanent-partial-disability rating, regardless of whether that disability causes the employee to be unable to secure employment. We reverse and remand for proceedings consistent with this opinion.
Respondent Todd C. Allan sustained a work-related injury to his lower back on September 28, 2010, while he was employed by relator R.D. Offutt Co. The steering rod broke on Allan’s conveyor belt, which caused him to fly backwards, *33land on his back, and hit a tire with his left shoulder. An MRI revealed degenerative disc disease caused by the fall, and Allan was restricted from performing many labor-related activities. Allan was 48 years old at the time of the injury.
Allan fled a petition seeking permanent-total-disability benefits in March 2013. Based on his age at the time of the injury, Allan was required to demonstrate “at least a 17 percent permanent-partial-disability rating of the whole body” in order to qualify for permanent-total-disability benefits. Minn.Stat. § 176.101, subd. 5(2)(i). To support his petition for benefits, Allan first relied on the September 28, 2010, back injury, which is assigned a permanent-partial-disability rating of 10 percent. See Minn. R. 5223.0390, subp. 3 (2013). Allan also relied on his non-work-related complete loss of teeth, which also is assigned a 10-percent rating. See Minn. R. 5223.0320, subp. 7 (2013). Relying on these two conditions, Allan claimed a permanent-partial-disability rating of 20 percent. Offutt opposed the petition for permanent-total-disability benefits, arguing that Allan’s non-work-related loss of teeth cannot be considered in determining whether he has satisfied the 17-percent threshold in subdivision 5(2)(i).
The compensation judge concluded that Allan established a 10-percent permanent-partial-disability rating based on his September 2010 back injury. The judge did not consider Allan’s complete loss of teeth in assessing his permanent-partial-disability whole-body rating, however, because the loss of teeth was fully corrected with dentures. Allan therefore did not satisfy the 17-percent threshold, and the compensation judge denied his petition for permanent-total-disability benefits.
Allan appealed and the WCCA reversed and remanded. Allan v. RD Offutt Co., 2014 WL 4253405 (Minn. WCCA Aug. 12, 2014). It concluded that the correctable nature of Allan’s loss of teeth was irrelevant to whether that condition could contribute to his permanent-partial-disability rating. Id. at *3. Relying on its own prior decision in Metzger v. Turck, Inc., 59 Minn. Workers’ Comp. Dec. 229 (WCCA 1999) (holding that a hysterectomy that did not affect employability could nevertheless contribute to the employee’s permanent-partial-disability rating), the WCCA further concluded that Allan’s loss of teeth need not affect his employability in order to contribute. to his permanent-partial-disability rating. Allan, 2014 WL 4253405, at *3-4. Offutt and its insurer now seek review by our court.
I.
The question presented here requires interpretation of the Workers’ Compensation Act, and therefore presents a question of law that we review de novo. Alcozer v. N. Country Food Bank, 635 N.W.2d 695, 701 (Minn.2001). “Our objective in statutory interpretation is to effectuate the intent of the legislature, reading the statute as a whole.” Rohmiller v. Hart, 811 N.W.2d 585, 589 (Minn.2012) (citing Minn.Stat. § 645.16 (2014)). In doing so, we “construe words and phrases according to their plain and ordinary meaning,” and we “give effect to all of [the statute’s] provisions; ‘no word, phrase, or sentence should be deemed superfluous, void, or insignificant.’” Am. Family Ins. Gp. v. Schroedl, 616 N.W.2d 273, 277 (Minn.2000) (quoting Amaral v. Saint Cloud Hosp., 598 N.W.2d 379, 384 (Minn.1999)). “When the language of a statute is plain and unambiguous, it is assumed to manifest legislative intent and must be given effect.” Burkstrand v. Burkstrand, 632 N.W.2d 206, 210 (Minn.2001).
A.
We begin by summarizing the statutory framework for permanent-total-*34disability benefits. The Workers’ Compensation Act provides compensation for “personal injury or death of an employee arising out of and in the course of employment.” Minn. Stat. § 176.021, subd. 1 (2014); see also Minn.Stat. § 176.011, subd. 16 (2014) (“ ‘Personal injury’ means any ... physical injury arising out of and in the course of employment.... ”). Disability benefits are awarded in accordance with the duration (temporary or permanent) and severity (partial or total) of the personal injury. See Minn.Stat. § 176.101 (2014). An injury that causes permanent total disability is compensable if the employee establishes:
(1) the total and permanent loss of the sight of both eyes, the loss of both arms at the shoulder, the loss of both legs so close to the hips that no effective artificial members can be used, complete and permanent paralysis, total and permanent loss of mental faculties; or
(2) any other injury which totally and permanently incapacitates the employee from working at an occupation which brings the employee an income....
Minn.Stat. § 176.101, subd. 5. Subdivision 5(1), which contains a group of injuries that presumptively establish a permanent total disability, is not at issue here. Allan relies instead on subdivision 5(2), which requires that an employee demonstrate a permanent-partial-disability rating of 13, 15, or 17 percent, depending on the employee’s age and education at the time of the injury.1 Id., subd. 5(2)(i)-(iii).
For purposes of [subdivision 5(2)], “totally and permanently incapacitated” means that the employee’s physical disability in combination with any one of item (i), (ii), or (Hi) causes the employee to be unable to secure anything more than sporadic employment resulting in an insubstantial income. Other factors not specified in item (i), (ii), or (iii), including the employee’s age, education, training and experience, may only be considered in determining whether an employee is totally and permanently incapacitated after the employee meets the threshold criteria of item (i), (ii), or (hi).
Id., subd. 5. The meaning of this final paragraph is the subject of this appeal.
B.
We hold that Minn.Stat. § 176.101, subd. 5(2), unambiguously requires that disabilities that contribute to an employee’s permanent-partial-disability rating must affect employability. Subdivision 5(2) provides that an employee is totally and permanently incapacitated if “the employee’s physical disability in combination with [the applicable permanent-partial-disability rating] causes the employee to be unable to secure anything more than sporadic employment resulting in an insubstantial income.” We construe words and phrases “according to rules of grammar and according to their most natural and common usage.... ” ILHC of Eagan, LLC v. Cty. of Dakota, 693 N.W.2d 412, 419 (Minn.2005) (quoting Minn.Stat. § 645.08 (2014)). “Combination” is defined as “the result or product of combining” or “a union or aggregate made by combining one thing with another.” Webster’s Third New International Dictionary 452 (1976). “Cause,” in turn, means “a person, thing, fact, or condition that brings about an effect or that produces or calls forth a resultant action or state.” Id. at 356. With these definitions in mind, the *35phrase “in combination with ... causes” means that the relevant aggregate factors must cause the employee to be unable to secure employment. Thus, subdivision 5(2) necessarily contains a causal nexus between employability and the work-related injury, and between employability and the disabilities that contribute to the permanent-partial-disability rating. “When the plain meaning of a statute is clear, a court must apply its plain language.” Krueger v. Zeman Constr. Co., 781 N.W.2d 858, 867 (Minn.2010).
Our conclusion is consistent with the overall context of the statute. Subdivision 5(2) contains two references to employability, both of which must be given effect. See Schroedl, 616 N.W.2d at 277. The first clause states that the work-related injury must “totally and permanently incapacitate!;] the employee from working at an occupation which brings the employee an income.” MinmStat. § 176.101, subd. 5(2). The definition of “totally and permanently incapacitated,” in turn, contains a second reference to employability: it states that the “physical disability in combination with” the disabilities contributing to the permanent-partial-disability rating must “cause[ ] the employee to be unable to secure anything more than sporadic employment resulting in an insubstantial income.” Id. If, as Allan and the dissent contend, the disabilities that contribute to the permanent-partial-disability rating are irrelevant to the employee’s inability to secure an income, this second reference to employability would be meaningless. Put differently, any disability used to satisfy the applicable permanent-partial-disability rating must also affect employability in order to “give effect to all of [the statute’s] provisions,” Schroedl, 616 N.W.2d at 277, in particular the provision that requires a causal effect on the employee’s ability to “secure anything more than sporadic employment resulting in an insubstantial income,” Minn. Stat. § 176.101, subd. 5(2).2
In addition, our conclusion conforms with the Legislature’s consistency in tying the provision of permanent-total-disability benefits to employability. See, e.g., Holland v. Indep. Sch. Dist. No. 332, 274 Minn. 380, 384, 144 N.W.2d 49, 51-52 (1966) (holding that an employee’s “inability to engage in gainful employment supported ah award for permanent total disability”); Yureko v. Prospect Foundry Co., 262 Minn. 480, 485, 115 N.W.2d 477, 481 (1962); Unger v. Balkan Mining Co., 248 Minn. 510, 515, 80 N.W.2d 846, 849 (1957) (“[I]f the loss or partial loss of a member should result in an employee’s not being able to engage in remunerative work, he may be eligible for total permanent disability.”); Berg v. Sadler, 235 Minn. 214, 219, 50 N.W.2d 266, 270 (1951) (concluding that an employee who, due to a work-related injury, could only work in “[a]n intermittent and limited capacity” was not precluded from recovering permanent-total-disability benefits). In Yureko, for example, a work-related injury left an employee “industrially blind.” 262 Minn, at 481-82, 115 N.W.2d at 478. The employee’s eyesight was fully corrected with glasses, however, and he obtained similar employment after the injury. Id. at 482, 115 N.W.2d at 478-79. We concluded that the employee was not entitled to permanent-total-disability benefits because he did not suffer “total loss of sight of both eyes.” Id. at 485, 115 N.W.2d at 481 (citing Minn.Stat. § 176.101, subd. 5 (1961)).3 We noted, however, that *36the employee may be entitled to additional benefits if his “ability to earn later diminishes into permanent total disability.” Id. Thus, we acknowledged that the injury could warrant permanent-total-disability benefits in the future, provided that it caused an inability to secure employment.
Yureko, of course, considered a previous version of Minn.Stat. § 176.101, subd. 5, that did not require the employee to establish a permanent-partial-disability rating. See Act of May 25, 1995, ch. 231, art. 1, § 21, 1995 Minn. Laws 1977, 1990-91 (codified as amended at Minn.Stat. § 176.101, subd. 5(2) (2014)) (adding the permanent-partial-disability rating requirement for obtaining permanent-total-disability benefits). But, our case law demonstrates that we have consistently tied the award of permanent-total-disability benefits to an inability to earn an income. It is therefore not surprising that the Legislature, upon creating an additional requirement for obtaining permanent-total-disability benefits, would tie that requirement to employability as well.
II.
Relying heavily on the WCCA’s decision in Metzger v. Turck, Inc., 59 Minn. Workers’ Comp. Dec. 229 (WCCA 1999), Allan argues that subsequent amendments to the Workers’ Compensation Act render our statutory interpretation in Yureko inapplicable to the current version of Minn. Stat. § 176.101, subd. 5(2). He notes that, in 1974, the Legislature amended Minn. Stat. § 176.021, subd. 3, to distinguish permanent-partial-disability benefits from other forms of compensation. The amendment provided that “[pjermanent partial disability is payable for functional loss of use or impairment of function, permanent in nature, and payment therefore shall be separate, distinct, and in addition to payment for any other compensation.” See Act of April 12, 1974, ch. 486, § 1, 1974 Minn. Laws 1230, 1231 (codified as amended at MinmStat. § 176.021, subd. 3 (2014)); see also Tracy v. Streater/Litton Indus., 283 N.W.2d 909, 914 (Minn.1979) (“[T]he legislature has made impairment of function compensable for its own sake in the form of damages separate and distinct from wage loss.”). When the Legislature amended MinmStat. § 176.101, subd. 5 again — to add the permanent-partial-disability rating requirement to the definition of permanent total disability — it did not amend the statement in MinmStat. § 176.021, subd. 3, that permanent-partial-disability benefits are “separate” and “distinct” from other benefits under the Workers’ Compensation Act. Allan and the dissent assert that, because permanent-partial-disability benefits are “payable for functional loss” rather than for wage loss, any disability that contributes to a permanent-partial-disability rating need not separately cause or contribute to the wage loss occasioned by the work-related injury that led to the petition for benefits.
The interpretation of MinmStat. § 176.101, subd. 5(2) advanced by Allan and the dissent is unreasonable for several reasons. First, MinmStat. § 176.021, subd. 3, makes clear that only permanent-parimi-disability benefits are “payable for functional loss of use or impairment of function.” Compensation for any other disability, including permanent total disability, is contingent on the employee’s inability to earn an income. See id. (“Liability ... for disability of a temporary total, temporary partial, and permanent total nature shall be considered as a com-*37timing product and part of the employee’s inability to earn or reduction in earning capacity due to injury.... ” (emphasis added)); see also 1 Lex K. Larson, Larson’s Workers’ Compensation § 1.03[4], at 1-9 (rev. ed. 2015) (“In [workers’] compensation, unlike tort, the only injuries compensated for are those which either actually or presumptively produce disability and thereby presumably affect earning power.”). The mere fact that permanent-partial-disability benefits are unconnected to an employee’s earning capacity does not mean that an employee’s permanent-partial-disability rating is similarly untethered to an ability to earn an income, when that rating is used to determine eligibility for permanent-total-disability benefits.
Second, both Allan and the dissent ignore the primary purpose of the Workers’ Compensation Act, which is to “pay compensation in every case of personal injury or death of an employee arising out of and in the course of employment.” Minn. Stat. § 176.021, subd. 1 (emphasis added); see also 1 Larson, supra, at 1-1 (“Workers’ compensation is a mechanism for providing cash-wage benefits and medical care to victims of work-connected injuries .... ”). Allan’s proffered rule, which the dissent adopts, would require the workers’ compensation judge — when determining eligibility for permanent-total-disability benefits — to consider disabilities that are wholly unconnected to employment and for which the employee is ineligible to receive workers’ compensation. Surely the Legislature did not intend such an expansive interpretation of the Workers’ Compensation Act.
Finally, regardless of whether the provision of permanent-partial-disability benefits is tied to wage loss, the Legislature provided a different test for determining eligibility for permanent-total-disability benefits under Minn.Stat. § 176.101, subd. 5(2). That test clearly requires that any injury contributing to the employee’s permanent partial disability rating must “cause[] the employee to be unable to secure anything more than sporadic employment resulting in an insubstantial income.” Id. The Legislature gives no indication that the provision of permanent-total-disability benefits should be contingent upon mere “functional loss of use or impairment of function.” We therefore reject Allan’s argument, as well as the WCCA’s reasoning in Metzger.4
III.
We conclude that, for the purpose of determining whether an employee is eligible for permanent-total-disability benefits under Minn.Stat. ■ § 176.101, subd. 5(2), a disability that contributes to the employee’s permanent-partial-disability rating must affect the employee’s ability “to secure anything more than sporadic employment resulting in an insubstantial income.”5 Because the WCCA did not decide whether Allan’s loss of teeth affects his employability, we remand to *38that court for further proceedings consistent with this opinion.
Reversed and remanded.
. The WCCA has held that non-work-related disabilities may contribute to the permanent-partial-disability rating. Frankhauser v. Fabcon, Inc., 57 Minn. Workers’ Comp. Dec. 250-51 (WCCA), aff'd without opinion, 569 N.W.2d 533 (Minn. 1997). Relators do not challenge this holding, and therefore we decline to address it.
. Although each of the disabilities must contribute to the inability to work, none must do so independently. The inquiry is whether, considered together in whatever measure, the disabilities cause the employee to be unable to work.
. At the time we decided Yureko, Minn.Stat. § 176.101, subd. 5 (1961), provided: “The *36total and permanent loss of the sight of both eyes, ... or any other injury which totally incapacitates the employee from working at an occupation which brings him an income constitutes total disability.”
. The dissent argues that we should give special deference to the long-standing decisions of the WCCA when, as here, those decisions are accompanied by legislative silence. Because we conclude that Minn.Stat. § 176.101, subd. 5(2) is clear and unambiguous, we need not address this issue. Whatever the level of deference, if any, that should be afforded to a long-standing regulatory decision coupled with legislative silence, it cannot overcome the clear and unambiguous text of the statute. ,
. Because we reverse the decision of the WCCA, we need not decide whether the WCCA's interpretation of ' Minn.Stat. § 176.101, subd. 5, violated the Fourteenth Amendment to the U.S. Constitution or Article I, Section 2, of the Minnesota Constitution.